From patchwork Wed Sep 15 16:49:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Moore X-Patchwork-Id: 12496861 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BAFC0C43219 for ; Wed, 15 Sep 2021 16:49:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A6CB761242 for ; Wed, 15 Sep 2021 16:49:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229594AbhIOQuu (ORCPT ); Wed, 15 Sep 2021 12:50:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36420 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229882AbhIOQuq (ORCPT ); Wed, 15 Sep 2021 12:50:46 -0400 Received: from mail-qk1-x72d.google.com (mail-qk1-x72d.google.com [IPv6:2607:f8b0:4864:20::72d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B52AAC061766 for ; Wed, 15 Sep 2021 09:49:27 -0700 (PDT) Received: by mail-qk1-x72d.google.com with SMTP id t4so4110697qkb.9 for ; Wed, 15 Sep 2021 09:49:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=paul-moore-com.20150623.gappssmtp.com; s=20150623; h=subject:from:to:date:message-id:in-reply-to:references:user-agent :mime-version:content-transfer-encoding; bh=8YWBwc8uGURi99B99vwd2XzI3RwHX+SBu+1nlNcEp0s=; b=gwpSc+sqmGFD+7Rsw5ir/MUYxl2xHh50iwfRpgeexsO2MC2QxDT85IvfP9I7UPNF9P /dPDmio5IkwlHcUX2Nd8XhiITJYVU9sYtQF/JYIBCKGCmrM0dBkCOvgAtVTnwfLYPY9/ rprML4FUAOY06MTnGtzt0GkzQSoPV0HV78ZBO+XvRQ8iUV4VxM+lK++6CND6nZ5LZaHv giaTdEBZG7npY50Quf9r3MEmbgUO3DcSGfrwDH5Bq7bajJwq4jDFKVsl/cs79GgQFfhX LWlbez7P46Dh84dPzT4vgklljf9lyL92UowljwiAmDB6ZqtVLl0txw6zuHAiSLrtmo5m ZyNQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:from:to:date:message-id:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=8YWBwc8uGURi99B99vwd2XzI3RwHX+SBu+1nlNcEp0s=; b=MwjDhWvkMgxmIR0Ib1ODcNlhMHo1armvQJHon9w9qYqvz0r0nmY7jhJpq4hlHY03Q3 Dwxik+sDdru13yjnd/ZCP3fvpKJ5OxLtF9LF36oDHa6KywZV3qpjabT8Az5MEGT7f1DG nuX82+kgpdT4v0vhFACmsPfAoQYMoSnIYmXYPFnQxT8dW41jRq5cr3jR853hFXyjqVoD cjbvU05tYocRNn0Sa6m4oVzXZ+tdsXawbZeo3DX06ugaZYRESntIUOLVNNfcKbR6jRDQ II+O6TNlHgurAFSRxV9sfrdiTKTP0r8/62lHbC5rVE3yv0Whvy6BSLn1e31DGT0qTwhJ hrCA== X-Gm-Message-State: AOAM533eTpZ1KlcyIRAFCFkjfKDGoQpNDLKg5JoX5dJ9KN4tCdEFJKXn ne1CIaeod3wDeyBuJ8vdueblC3eGjuba X-Google-Smtp-Source: ABdhPJw7Op73H/5ylV88OdiIwTFRD0SHdDT0xIZ6LtpwdhTY4Jdqissl4uJTOcqq3JZy2Tv2wPon3Q== X-Received: by 2002:a05:620a:11a9:: with SMTP id c9mr61961qkk.89.1631724566417; Wed, 15 Sep 2021 09:49:26 -0700 (PDT) Received: from localhost (pool-96-237-52-188.bstnma.fios.verizon.net. [96.237.52.188]) by smtp.gmail.com with ESMTPSA id 9sm266579qtz.83.2021.09.15.09.49.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Sep 2021 09:49:25 -0700 (PDT) Subject: [PATCH v4 1/8] audit: prepare audit_context for use in calling contexts beyond syscalls From: Paul Moore To: linux-security-module@vger.kernel.org, selinux@vger.kernel.org, linux-audit@redhat.com, io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jens Axboe , Pavel Begunkov , Kumar Kartikeya Dwivedi Date: Wed, 15 Sep 2021 12:49:25 -0400 Message-ID: <163172456530.88001.13707423554814526028.stgit@olly> In-Reply-To: <163172413301.88001.16054830862146685573.stgit@olly> References: <163172413301.88001.16054830862146685573.stgit@olly> User-Agent: StGit/1.1 MIME-Version: 1.0 Precedence: bulk List-ID: This patch cleans up some of our audit_context handling by abstracting out the reset and return code fixup handling to dedicated functions. Not only does this help make things easier to read and inspect, it allows for easier reuse by future patches. We also convert the simple audit_context->in_syscall flag into an enum which can be used to by future patches to indicate a calling context other than the syscall context. Thanks to Richard Guy Briggs for review and feedback. Acked-by: Richard Guy Briggs Signed-off-by: Paul Moore --- v4: - fix some spelling errors in the comments v3: - removed work-in-progress warning from the description v2: - no change v1: - initial draft --- kernel/audit.h | 5 + kernel/auditsc.c | 256 ++++++++++++++++++++++++++++++++++-------------------- 2 files changed, 167 insertions(+), 94 deletions(-) diff --git a/kernel/audit.h b/kernel/audit.h index d6a2c899a8db..13abc48de0bd 100644 --- a/kernel/audit.h +++ b/kernel/audit.h @@ -100,7 +100,10 @@ struct audit_proctitle { /* The per-task audit context. */ struct audit_context { int dummy; /* must be the first element */ - int in_syscall; /* 1 if task is in a syscall */ + enum { + AUDIT_CTX_UNUSED, /* audit_context is currently unused */ + AUDIT_CTX_SYSCALL, /* in use by syscall */ + } context; enum audit_state state, current_state; unsigned int serial; /* serial number for record */ int major; /* syscall number */ diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 8dd73a64f921..f3d309b05c2d 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -915,10 +915,80 @@ static inline void audit_free_aux(struct audit_context *context) context->aux = aux->next; kfree(aux); } + context->aux = NULL; while ((aux = context->aux_pids)) { context->aux_pids = aux->next; kfree(aux); } + context->aux_pids = NULL; +} + +/** + * audit_reset_context - reset a audit_context structure + * @ctx: the audit_context to reset + * + * All fields in the audit_context will be reset to an initial state, all + * references held by fields will be dropped, and private memory will be + * released. When this function returns the audit_context will be suitable + * for reuse, so long as the passed context is not NULL or a dummy context. + */ +static void audit_reset_context(struct audit_context *ctx) +{ + if (!ctx) + return; + + /* if ctx is non-null, reset the "ctx->state" regardless */ + ctx->context = AUDIT_CTX_UNUSED; + if (ctx->dummy) + return; + + /* + * NOTE: It shouldn't matter in what order we release the fields, so + * release them in the order in which they appear in the struct; + * this gives us some hope of quickly making sure we are + * resetting the audit_context properly. + * + * Other things worth mentioning: + * - we don't reset "dummy" + * - we don't reset "state", we do reset "current_state" + * - we preserve "filterkey" if "state" is AUDIT_STATE_RECORD + * - much of this is likely overkill, but play it safe for now + * - we really need to work on improving the audit_context struct + */ + + ctx->current_state = ctx->state; + ctx->serial = 0; + ctx->major = 0; + ctx->ctime = (struct timespec64){ .tv_sec = 0, .tv_nsec = 0 }; + memset(ctx->argv, 0, sizeof(ctx->argv)); + ctx->return_code = 0; + ctx->prio = (ctx->state == AUDIT_STATE_RECORD ? ~0ULL : 0); + ctx->return_valid = AUDITSC_INVALID; + audit_free_names(ctx); + if (ctx->state != AUDIT_STATE_RECORD) { + kfree(ctx->filterkey); + ctx->filterkey = NULL; + } + audit_free_aux(ctx); + kfree(ctx->sockaddr); + ctx->sockaddr = NULL; + ctx->sockaddr_len = 0; + ctx->pid = ctx->ppid = 0; + ctx->uid = ctx->euid = ctx->suid = ctx->fsuid = KUIDT_INIT(0); + ctx->gid = ctx->egid = ctx->sgid = ctx->fsgid = KGIDT_INIT(0); + ctx->personality = 0; + ctx->arch = 0; + ctx->target_pid = 0; + ctx->target_auid = ctx->target_uid = KUIDT_INIT(0); + ctx->target_sessionid = 0; + ctx->target_sid = 0; + ctx->target_comm[0] = '\0'; + unroll_tree_refs(ctx, NULL, 0); + WARN_ON(!list_empty(&ctx->killed_trees)); + ctx->type = 0; + audit_free_module(ctx); + ctx->fds[0] = -1; + audit_proctitle_free(ctx); } static inline struct audit_context *audit_alloc_context(enum audit_state state) @@ -928,6 +998,7 @@ static inline struct audit_context *audit_alloc_context(enum audit_state state) context = kzalloc(sizeof(*context), GFP_KERNEL); if (!context) return NULL; + context->context = AUDIT_CTX_UNUSED; context->state = state; context->prio = state == AUDIT_STATE_RECORD ? ~0ULL : 0; INIT_LIST_HEAD(&context->killed_trees); @@ -953,7 +1024,7 @@ int audit_alloc(struct task_struct *tsk) char *key = NULL; if (likely(!audit_ever_enabled)) - return 0; /* Return if not auditing. */ + return 0; state = audit_filter_task(tsk, &key); if (state == AUDIT_STATE_DISABLED) { @@ -975,14 +1046,10 @@ int audit_alloc(struct task_struct *tsk) static inline void audit_free_context(struct audit_context *context) { - audit_free_module(context); - audit_free_names(context); - unroll_tree_refs(context, NULL, 0); + /* resetting is extra work, but it is likely just noise */ + audit_reset_context(context); free_tree_refs(context); - audit_free_aux(context); kfree(context->filterkey); - kfree(context->sockaddr); - audit_proctitle_free(context); kfree(context); } @@ -1489,29 +1556,35 @@ static void audit_log_exit(void) context->personality = current->personality; - ab = audit_log_start(context, GFP_KERNEL, AUDIT_SYSCALL); - if (!ab) - return; /* audit_panic has been called */ - audit_log_format(ab, "arch=%x syscall=%d", - context->arch, context->major); - if (context->personality != PER_LINUX) - audit_log_format(ab, " per=%lx", context->personality); - if (context->return_valid != AUDITSC_INVALID) - audit_log_format(ab, " success=%s exit=%ld", - (context->return_valid==AUDITSC_SUCCESS)?"yes":"no", - context->return_code); - - audit_log_format(ab, - " a0=%lx a1=%lx a2=%lx a3=%lx items=%d", - context->argv[0], - context->argv[1], - context->argv[2], - context->argv[3], - context->name_count); - - audit_log_task_info(ab); - audit_log_key(ab, context->filterkey); - audit_log_end(ab); + switch (context->context) { + case AUDIT_CTX_SYSCALL: + ab = audit_log_start(context, GFP_KERNEL, AUDIT_SYSCALL); + if (!ab) + return; + audit_log_format(ab, "arch=%x syscall=%d", + context->arch, context->major); + if (context->personality != PER_LINUX) + audit_log_format(ab, " per=%lx", context->personality); + if (context->return_valid != AUDITSC_INVALID) + audit_log_format(ab, " success=%s exit=%ld", + (context->return_valid == AUDITSC_SUCCESS ? + "yes" : "no"), + context->return_code); + audit_log_format(ab, + " a0=%lx a1=%lx a2=%lx a3=%lx items=%d", + context->argv[0], + context->argv[1], + context->argv[2], + context->argv[3], + context->name_count); + audit_log_task_info(ab); + audit_log_key(ab, context->filterkey); + audit_log_end(ab); + break; + default: + BUG(); + break; + } for (aux = context->aux; aux; aux = aux->next) { @@ -1602,14 +1675,15 @@ static void audit_log_exit(void) audit_log_name(context, n, NULL, i++, &call_panic); } - audit_log_proctitle(); + if (context->context == AUDIT_CTX_SYSCALL) + audit_log_proctitle(); /* Send end of event record to help user space know we are finished */ ab = audit_log_start(context, GFP_KERNEL, AUDIT_EOE); if (ab) audit_log_end(ab); if (call_panic) - audit_panic("error converting sid to string"); + audit_panic("error in audit_log_exit()"); } /** @@ -1625,6 +1699,7 @@ void __audit_free(struct task_struct *tsk) if (!context) return; + /* this may generate CONFIG_CHANGE records */ if (!list_empty(&context->killed_trees)) audit_kill_trees(context); @@ -1633,7 +1708,8 @@ void __audit_free(struct task_struct *tsk) * random task_struct that doesn't doesn't have any meaningful data we * need to log via audit_log_exit(). */ - if (tsk == current && !context->dummy && context->in_syscall) { + if (tsk == current && !context->dummy && + context->context == AUDIT_CTX_SYSCALL) { context->return_valid = AUDITSC_INVALID; context->return_code = 0; @@ -1647,6 +1723,34 @@ void __audit_free(struct task_struct *tsk) audit_free_context(context); } +/** + * audit_return_fixup - fixup the return codes in the audit_context + * @ctx: the audit_context + * @success: true/false value to indicate if the operation succeeded or not + * @code: operation return code + * + * We need to fixup the return code in the audit logs if the actual return + * codes are later going to be fixed by the arch specific signal handlers. + */ +static void audit_return_fixup(struct audit_context *ctx, + int success, long code) +{ + /* + * This is actually a test for: + * (rc == ERESTARTSYS ) || (rc == ERESTARTNOINTR) || + * (rc == ERESTARTNOHAND) || (rc == ERESTART_RESTARTBLOCK) + * + * but is faster than a bunch of || + */ + if (unlikely(code <= -ERESTARTSYS) && + (code >= -ERESTART_RESTARTBLOCK) && + (code != -ENOIOCTLCMD)) + ctx->return_code = -EINTR; + else + ctx->return_code = code; + ctx->return_valid = (success ? AUDITSC_SUCCESS : AUDITSC_FAILURE); +} + /** * __audit_syscall_entry - fill in an audit record at syscall entry * @major: major syscall type (function) @@ -1672,7 +1776,12 @@ void __audit_syscall_entry(int major, unsigned long a1, unsigned long a2, if (!audit_enabled || !context) return; - BUG_ON(context->in_syscall || context->name_count); + WARN_ON(context->context != AUDIT_CTX_UNUSED); + WARN_ON(context->name_count); + if (context->context != AUDIT_CTX_UNUSED || context->name_count) { + audit_panic("unrecoverable error in audit_syscall_entry()"); + return; + } state = context->state; if (state == AUDIT_STATE_DISABLED) @@ -1691,10 +1800,8 @@ void __audit_syscall_entry(int major, unsigned long a1, unsigned long a2, context->argv[1] = a2; context->argv[2] = a3; context->argv[3] = a4; - context->serial = 0; - context->in_syscall = 1; + context->context = AUDIT_CTX_SYSCALL; context->current_state = state; - context->ppid = 0; ktime_get_coarse_real_ts64(&context->ctime); } @@ -1711,63 +1818,27 @@ void __audit_syscall_entry(int major, unsigned long a1, unsigned long a2, */ void __audit_syscall_exit(int success, long return_code) { - struct audit_context *context; + struct audit_context *context = audit_context(); - context = audit_context(); - if (!context) - return; + if (!context || context->dummy || + context->context != AUDIT_CTX_SYSCALL) + goto out; + /* this may generate CONFIG_CHANGE records */ if (!list_empty(&context->killed_trees)) audit_kill_trees(context); - if (!context->dummy && context->in_syscall) { - if (success) - context->return_valid = AUDITSC_SUCCESS; - else - context->return_valid = AUDITSC_FAILURE; - - /* - * we need to fix up the return code in the audit logs if the - * actual return codes are later going to be fixed up by the - * arch specific signal handlers - * - * This is actually a test for: - * (rc == ERESTARTSYS ) || (rc == ERESTARTNOINTR) || - * (rc == ERESTARTNOHAND) || (rc == ERESTART_RESTARTBLOCK) - * - * but is faster than a bunch of || - */ - if (unlikely(return_code <= -ERESTARTSYS) && - (return_code >= -ERESTART_RESTARTBLOCK) && - (return_code != -ENOIOCTLCMD)) - context->return_code = -EINTR; - else - context->return_code = return_code; - - audit_filter_syscall(current, context); - audit_filter_inodes(current, context); - if (context->current_state == AUDIT_STATE_RECORD) - audit_log_exit(); - } + /* run through both filters to ensure we set the filterkey properly */ + audit_filter_syscall(current, context); + audit_filter_inodes(current, context); + if (context->current_state < AUDIT_STATE_RECORD) + goto out; - context->in_syscall = 0; - context->prio = context->state == AUDIT_STATE_RECORD ? ~0ULL : 0; + audit_return_fixup(context, success, return_code); + audit_log_exit(); - audit_free_module(context); - audit_free_names(context); - unroll_tree_refs(context, NULL, 0); - audit_free_aux(context); - context->aux = NULL; - context->aux_pids = NULL; - context->target_pid = 0; - context->target_sid = 0; - context->sockaddr_len = 0; - context->type = 0; - context->fds[0] = -1; - if (context->state != AUDIT_STATE_RECORD) { - kfree(context->filterkey); - context->filterkey = NULL; - } +out: + audit_reset_context(context); } static inline void handle_one(const struct inode *inode) @@ -1919,7 +1990,7 @@ void __audit_getname(struct filename *name) struct audit_context *context = audit_context(); struct audit_names *n; - if (!context->in_syscall) + if (context->context == AUDIT_CTX_UNUSED) return; n = audit_alloc_name(context, AUDIT_TYPE_UNKNOWN); @@ -1991,7 +2062,7 @@ void __audit_inode(struct filename *name, const struct dentry *dentry, struct list_head *list = &audit_filter_list[AUDIT_FILTER_FS]; int i; - if (!context->in_syscall) + if (context->context == AUDIT_CTX_UNUSED) return; rcu_read_lock(); @@ -2109,7 +2180,7 @@ void __audit_inode_child(struct inode *parent, struct list_head *list = &audit_filter_list[AUDIT_FILTER_FS]; int i; - if (!context->in_syscall) + if (context->context == AUDIT_CTX_UNUSED) return; rcu_read_lock(); @@ -2208,7 +2279,7 @@ EXPORT_SYMBOL_GPL(__audit_inode_child); int auditsc_get_stamp(struct audit_context *ctx, struct timespec64 *t, unsigned int *serial) { - if (!ctx->in_syscall) + if (ctx->context == AUDIT_CTX_UNUSED) return 0; if (!ctx->serial) ctx->serial = audit_serial(); @@ -2706,8 +2777,7 @@ void audit_seccomp_actions_logged(const char *names, const char *old_names, struct list_head *audit_killed_trees(void) { struct audit_context *ctx = audit_context(); - - if (likely(!ctx || !ctx->in_syscall)) + if (likely(!ctx || ctx->context == AUDIT_CTX_UNUSED)) return NULL; return &ctx->killed_trees; } From patchwork Wed Sep 15 16:49:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Moore X-Patchwork-Id: 12496863 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 098D5C43217 for ; Wed, 15 Sep 2021 16:49:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E81516124D for ; Wed, 15 Sep 2021 16:49:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229730AbhIOQu4 (ORCPT ); Wed, 15 Sep 2021 12:50:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229854AbhIOQux (ORCPT ); Wed, 15 Sep 2021 12:50:53 -0400 Received: from mail-qv1-xf2a.google.com (mail-qv1-xf2a.google.com [IPv6:2607:f8b0:4864:20::f2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E1B8FC061766 for ; Wed, 15 Sep 2021 09:49:33 -0700 (PDT) Received: by mail-qv1-xf2a.google.com with SMTP id w8so2321946qvt.0 for ; Wed, 15 Sep 2021 09:49:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=paul-moore-com.20150623.gappssmtp.com; s=20150623; h=subject:from:to:date:message-id:in-reply-to:references:user-agent :mime-version:content-transfer-encoding; bh=xbkucCrzx5rZDNih56zZM/KKK95ZBnmgKvPNE6CF0sU=; b=fMaw7nCrZHl+rXdq7ad8nll6+Efc18lr7i9Pb+ZmfPbdVO0lPcEFU1kepB2K2cJ8Rd EicJqJcmsZooOkW+wHDCIEjLi+rcgGfUwEWOBPr3TIZrKrjLPXaK6kNFzbHlxjhxi2Jp QcBiPNxVw+V/dQoZYUNkBJKBQf++FIPsBIuQiJE2jY8bbyjxEZWALybI701GHMAMTM7p Urv2p2Pgtrz+xMFeA1Gp+ROiK0wB7JzIG+VByjQP3LvsFojSVLn/8Y6fXPGF4D6zSFIy nb0h2WfLa/kr5yMdsccspYr8UYeJuQOAoEkV1aEEV+K0tTkm+hfsn72vbFZcy+LZM9wL oQUA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:from:to:date:message-id:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=xbkucCrzx5rZDNih56zZM/KKK95ZBnmgKvPNE6CF0sU=; b=iHHS7NqW+wTZALBa5F4EgBZZ4VHUuwMyr/NSACV5U1/YGYhSt/y2GNa0qEPohaX7wx 0nmsbjrIalPBhuC/ghhRi08cDiWkJGGKiTOxdjacPQMJuHonO7JInCNzZZCz+Fy7jyir VjdSbc+AMyYCg7nhrdVXDeGEpXEJ/H/KBOevDgpFk1oPbdgdDt8opKsGbyTizk3yAOvm bR8xiPpznc6j7pYXVxExBxeTQRwNJlSDoJFzXCeDaFqAsiAdX9uVChVQ1502K2epq+R5 a1SjIjLpfERG8CoBlWSYaF4XFqwGqWeqYEh+bmxXONERS25rcYO+TBrWj6AYmewg+BDi /xog== X-Gm-Message-State: AOAM5318kK1Vm9HdBpRiwUQ9DfcSEUThH662WzZYowJMIck1K8mnjNHa I50JKY4NsceUG0jUV97+Mh4Eo/apPAHh X-Google-Smtp-Source: ABdhPJyBi2ruCJwGONrPq2+rY/9N84c137b7q3sZEdLPymBZnZK1F+UhFlYHnnliM9SDidpxHRoCrA== X-Received: by 2002:a0c:ab12:: with SMTP id h18mr606151qvb.55.1631724572566; Wed, 15 Sep 2021 09:49:32 -0700 (PDT) Received: from localhost (pool-96-237-52-188.bstnma.fios.verizon.net. [96.237.52.188]) by smtp.gmail.com with ESMTPSA id c28sm356578qkl.69.2021.09.15.09.49.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Sep 2021 09:49:32 -0700 (PDT) Subject: [PATCH v4 2/8] audit,io_uring,io-wq: add some basic audit support to io_uring From: Paul Moore To: linux-security-module@vger.kernel.org, selinux@vger.kernel.org, linux-audit@redhat.com, io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jens Axboe , Pavel Begunkov , Kumar Kartikeya Dwivedi Date: Wed, 15 Sep 2021 12:49:31 -0400 Message-ID: <163172457152.88001.12700049763432531651.stgit@olly> In-Reply-To: <163172413301.88001.16054830862146685573.stgit@olly> References: <163172413301.88001.16054830862146685573.stgit@olly> User-Agent: StGit/1.1 MIME-Version: 1.0 Precedence: bulk List-ID: This patch adds basic auditing to io_uring operations, regardless of their context. This is accomplished by allocating audit_context structures for the io-wq worker and io_uring SQPOLL kernel threads as well as explicitly auditing the io_uring operations in io_issue_sqe(). Individual io_uring operations can bypass auditing through the "audit_skip" field in the struct io_op_def definition for the operation; although great care must be taken so that security relevant io_uring operations do not bypass auditing; please contact the audit mailing list (see the MAINTAINERS file) with any questions. The io_uring operations are audited using a new AUDIT_URINGOP record, an example is shown below: type=UNKNOWN[1336] msg=audit(1630523381.288:260): uring_op=19 success=yes exit=0 items=0 ppid=853 pid=1204 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null) AUID="root" UID="root" GID="root" EUID="root" SUID="root" FSUID="root" EGID="root" SGID="root" FSGID="root" Thanks to Richard Guy Briggs for review and feedback. Signed-off-by: Paul Moore --- v4: - removed some work-in-progress comments - removed the auid logging in audit_log_uring() v3: - removed work-in-progress warning from the description v2: - added dummy funcs for audit_uring_{entry,exit}() - replaced opcode checks in io_issue_sqe() with audit_skip checks - moved fastpath checks into audit_uring_{entry,exit}() - audit_log_uring() uses GFP_ATOMIC - don't record the arch in __audit_uring_entry() v1: - initial draft --- fs/io-wq.c | 4 + fs/io_uring.c | 55 +++++++++++++-- include/linux/audit.h | 26 +++++++ include/uapi/linux/audit.h | 1 kernel/audit.h | 2 + kernel/auditsc.c | 166 ++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 248 insertions(+), 6 deletions(-) diff --git a/fs/io-wq.c b/fs/io-wq.c index 6c55362c1f99..dac5c5961c9d 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "io-wq.h" @@ -562,6 +563,8 @@ static int io_wqe_worker(void *data) snprintf(buf, sizeof(buf), "iou-wrk-%d", wq->task->pid); set_task_comm(current, buf); + audit_alloc_kernel(current); + while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) { long ret; @@ -601,6 +604,7 @@ static int io_wqe_worker(void *data) io_worker_handle_work(worker); } + audit_free(current); io_worker_exit(worker); return 0; } diff --git a/fs/io_uring.c b/fs/io_uring.c index 16fb7436043c..388754b24785 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -79,6 +79,7 @@ #include #include #include +#include #define CREATE_TRACE_POINTS #include @@ -917,6 +918,8 @@ struct io_op_def { unsigned needs_async_setup : 1; /* should block plug */ unsigned plug : 1; + /* skip auditing */ + unsigned audit_skip : 1; /* size of async data needed, if any */ unsigned short async_size; }; @@ -930,6 +933,7 @@ static const struct io_op_def io_op_defs[] = { .buffer_select = 1, .needs_async_setup = 1, .plug = 1, + .audit_skip = 1, .async_size = sizeof(struct io_async_rw), }, [IORING_OP_WRITEV] = { @@ -939,16 +943,19 @@ static const struct io_op_def io_op_defs[] = { .pollout = 1, .needs_async_setup = 1, .plug = 1, + .audit_skip = 1, .async_size = sizeof(struct io_async_rw), }, [IORING_OP_FSYNC] = { .needs_file = 1, + .audit_skip = 1, }, [IORING_OP_READ_FIXED] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .plug = 1, + .audit_skip = 1, .async_size = sizeof(struct io_async_rw), }, [IORING_OP_WRITE_FIXED] = { @@ -957,15 +964,20 @@ static const struct io_op_def io_op_defs[] = { .unbound_nonreg_file = 1, .pollout = 1, .plug = 1, + .audit_skip = 1, .async_size = sizeof(struct io_async_rw), }, [IORING_OP_POLL_ADD] = { .needs_file = 1, .unbound_nonreg_file = 1, + .audit_skip = 1, + }, + [IORING_OP_POLL_REMOVE] = { + .audit_skip = 1, }, - [IORING_OP_POLL_REMOVE] = {}, [IORING_OP_SYNC_FILE_RANGE] = { .needs_file = 1, + .audit_skip = 1, }, [IORING_OP_SENDMSG] = { .needs_file = 1, @@ -983,18 +995,23 @@ static const struct io_op_def io_op_defs[] = { .async_size = sizeof(struct io_async_msghdr), }, [IORING_OP_TIMEOUT] = { + .audit_skip = 1, .async_size = sizeof(struct io_timeout_data), }, [IORING_OP_TIMEOUT_REMOVE] = { /* used by timeout updates' prep() */ + .audit_skip = 1, }, [IORING_OP_ACCEPT] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, }, - [IORING_OP_ASYNC_CANCEL] = {}, + [IORING_OP_ASYNC_CANCEL] = { + .audit_skip = 1, + }, [IORING_OP_LINK_TIMEOUT] = { + .audit_skip = 1, .async_size = sizeof(struct io_timeout_data), }, [IORING_OP_CONNECT] = { @@ -1009,14 +1026,19 @@ static const struct io_op_def io_op_defs[] = { }, [IORING_OP_OPENAT] = {}, [IORING_OP_CLOSE] = {}, - [IORING_OP_FILES_UPDATE] = {}, - [IORING_OP_STATX] = {}, + [IORING_OP_FILES_UPDATE] = { + .audit_skip = 1, + }, + [IORING_OP_STATX] = { + .audit_skip = 1, + }, [IORING_OP_READ] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .buffer_select = 1, .plug = 1, + .audit_skip = 1, .async_size = sizeof(struct io_async_rw), }, [IORING_OP_WRITE] = { @@ -1025,39 +1047,50 @@ static const struct io_op_def io_op_defs[] = { .unbound_nonreg_file = 1, .pollout = 1, .plug = 1, + .audit_skip = 1, .async_size = sizeof(struct io_async_rw), }, [IORING_OP_FADVISE] = { .needs_file = 1, + .audit_skip = 1, }, [IORING_OP_MADVISE] = {}, [IORING_OP_SEND] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollout = 1, + .audit_skip = 1, }, [IORING_OP_RECV] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .buffer_select = 1, + .audit_skip = 1, }, [IORING_OP_OPENAT2] = { }, [IORING_OP_EPOLL_CTL] = { .unbound_nonreg_file = 1, + .audit_skip = 1, }, [IORING_OP_SPLICE] = { .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, + .audit_skip = 1, + }, + [IORING_OP_PROVIDE_BUFFERS] = { + .audit_skip = 1, + }, + [IORING_OP_REMOVE_BUFFERS] = { + .audit_skip = 1, }, - [IORING_OP_PROVIDE_BUFFERS] = {}, - [IORING_OP_REMOVE_BUFFERS] = {}, [IORING_OP_TEE] = { .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, + .audit_skip = 1, }, [IORING_OP_SHUTDOWN] = { .needs_file = 1, @@ -6591,6 +6624,9 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags) if ((req->flags & REQ_F_CREDS) && req->creds != current_cred()) creds = override_creds(req->creds); + if (!io_op_defs[req->opcode].audit_skip) + audit_uring_entry(req->opcode); + switch (req->opcode) { case IORING_OP_NOP: ret = io_nop(req, issue_flags); @@ -6706,6 +6742,9 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags) break; } + if (!io_op_defs[req->opcode].audit_skip) + audit_uring_exit(!ret, ret); + if (creds) revert_creds(creds); if (ret) @@ -7360,6 +7399,8 @@ static int io_sq_thread(void *data) set_cpus_allowed_ptr(current, cpu_online_mask); current->flags |= PF_NO_SETAFFINITY; + audit_alloc_kernel(current); + mutex_lock(&sqd->lock); while (1) { bool cap_entries, sqt_spin = false; @@ -7425,6 +7466,8 @@ static int io_sq_thread(void *data) io_run_task_work(); mutex_unlock(&sqd->lock); + audit_free(current); + complete(&sqd->exited); do_exit(0); } diff --git a/include/linux/audit.h b/include/linux/audit.h index 82b7c1116a85..d656a06dd909 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -286,7 +286,10 @@ static inline int audit_signal_info(int sig, struct task_struct *t) /* These are defined in auditsc.c */ /* Public API */ extern int audit_alloc(struct task_struct *task); +extern int audit_alloc_kernel(struct task_struct *task); extern void __audit_free(struct task_struct *task); +extern void __audit_uring_entry(u8 op); +extern void __audit_uring_exit(int success, long code); extern void __audit_syscall_entry(int major, unsigned long a0, unsigned long a1, unsigned long a2, unsigned long a3); extern void __audit_syscall_exit(int ret_success, long ret_value); @@ -323,6 +326,21 @@ static inline void audit_free(struct task_struct *task) if (unlikely(task->audit_context)) __audit_free(task); } +static inline void audit_uring_entry(u8 op) +{ + /* + * We intentionally check audit_context() before audit_enabled as most + * Linux systems (as of ~2021) rely on systemd which forces audit to + * be enabled regardless of the user's audit configuration. + */ + if (unlikely(audit_context() && audit_enabled)) + __audit_uring_entry(op); +} +static inline void audit_uring_exit(int success, long code) +{ + if (unlikely(!audit_dummy_context())) + __audit_uring_exit(success, code); +} static inline void audit_syscall_entry(int major, unsigned long a0, unsigned long a1, unsigned long a2, unsigned long a3) @@ -554,8 +572,16 @@ static inline int audit_alloc(struct task_struct *task) { return 0; } +static inline int audit_alloc_kernel(struct task_struct *task) +{ + return 0; +} static inline void audit_free(struct task_struct *task) { } +static inline void audit_uring_entry(u8 op) +{ } +static inline void audit_uring_exit(int success, long code) +{ } static inline void audit_syscall_entry(int major, unsigned long a0, unsigned long a1, unsigned long a2, unsigned long a3) diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h index daa481729e9b..a1997697c8b1 100644 --- a/include/uapi/linux/audit.h +++ b/include/uapi/linux/audit.h @@ -118,6 +118,7 @@ #define AUDIT_TIME_ADJNTPVAL 1333 /* NTP value adjustment */ #define AUDIT_BPF 1334 /* BPF subsystem */ #define AUDIT_EVENT_LISTENER 1335 /* Task joined multicast read socket */ +#define AUDIT_URINGOP 1336 /* io_uring operation */ #define AUDIT_AVC 1400 /* SE Linux avc denial or grant */ #define AUDIT_SELINUX_ERR 1401 /* Internal SE Linux Errors */ diff --git a/kernel/audit.h b/kernel/audit.h index 13abc48de0bd..d1161e3b83e2 100644 --- a/kernel/audit.h +++ b/kernel/audit.h @@ -103,10 +103,12 @@ struct audit_context { enum { AUDIT_CTX_UNUSED, /* audit_context is currently unused */ AUDIT_CTX_SYSCALL, /* in use by syscall */ + AUDIT_CTX_URING, /* in use by io_uring */ } context; enum audit_state state, current_state; unsigned int serial; /* serial number for record */ int major; /* syscall number */ + int uring_op; /* uring operation */ struct timespec64 ctime; /* time of syscall entry */ unsigned long argv[4]; /* syscall arguments */ long return_code;/* syscall return code */ diff --git a/kernel/auditsc.c b/kernel/auditsc.c index f3d309b05c2d..6dda448fb826 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -959,6 +959,7 @@ static void audit_reset_context(struct audit_context *ctx) ctx->current_state = ctx->state; ctx->serial = 0; ctx->major = 0; + ctx->uring_op = 0; ctx->ctime = (struct timespec64){ .tv_sec = 0, .tv_nsec = 0 }; memset(ctx->argv, 0, sizeof(ctx->argv)); ctx->return_code = 0; @@ -1044,6 +1045,31 @@ int audit_alloc(struct task_struct *tsk) return 0; } +/** + * audit_alloc_kernel - allocate an audit_context for a kernel task + * @tsk: the kernel task + * + * Similar to the audit_alloc() function, but intended for kernel private + * threads. Returns zero on success, negative values on failure. + */ +int audit_alloc_kernel(struct task_struct *tsk) +{ + /* + * At the moment we are just going to call into audit_alloc() to + * simplify the code, but there two things to keep in mind with this + * approach: + * + * 1. Filtering internal kernel tasks is a bit laughable in almost all + * cases, but there is at least one case where there is a benefit: + * the '-a task,never' case allows the admin to effectively disable + * task auditing at runtime. + * + * 2. The {set,clear}_task_syscall_work() ops likely have zero effect + * on these internal kernel tasks, but they probably don't hurt either. + */ + return audit_alloc(tsk); +} + static inline void audit_free_context(struct audit_context *context) { /* resetting is extra work, but it is likely just noise */ @@ -1546,6 +1572,44 @@ static void audit_log_proctitle(void) audit_log_end(ab); } +/** + * audit_log_uring - generate a AUDIT_URINGOP record + * @ctx: the audit context + */ +static void audit_log_uring(struct audit_context *ctx) +{ + struct audit_buffer *ab; + const struct cred *cred; + + ab = audit_log_start(ctx, GFP_ATOMIC, AUDIT_URINGOP); + if (!ab) + return; + cred = current_cred(); + audit_log_format(ab, "uring_op=%d", ctx->uring_op); + if (ctx->return_valid != AUDITSC_INVALID) + audit_log_format(ab, " success=%s exit=%ld", + (ctx->return_valid == AUDITSC_SUCCESS ? + "yes" : "no"), + ctx->return_code); + audit_log_format(ab, + " items=%d" + " ppid=%d pid=%d uid=%u gid=%u euid=%u suid=%u" + " fsuid=%u egid=%u sgid=%u fsgid=%u", + ctx->name_count, + task_ppid_nr(current), task_tgid_nr(current), + from_kuid(&init_user_ns, cred->uid), + from_kgid(&init_user_ns, cred->gid), + from_kuid(&init_user_ns, cred->euid), + from_kuid(&init_user_ns, cred->suid), + from_kuid(&init_user_ns, cred->fsuid), + from_kgid(&init_user_ns, cred->egid), + from_kgid(&init_user_ns, cred->sgid), + from_kgid(&init_user_ns, cred->fsgid)); + audit_log_task_context(ab); + audit_log_key(ab, ctx->filterkey); + audit_log_end(ab); +} + static void audit_log_exit(void) { int i, call_panic = 0; @@ -1581,6 +1645,9 @@ static void audit_log_exit(void) audit_log_key(ab, context->filterkey); audit_log_end(ab); break; + case AUDIT_CTX_URING: + audit_log_uring(context); + break; default: BUG(); break; @@ -1751,6 +1818,105 @@ static void audit_return_fixup(struct audit_context *ctx, ctx->return_valid = (success ? AUDITSC_SUCCESS : AUDITSC_FAILURE); } +/** + * __audit_uring_entry - prepare the kernel task's audit context for io_uring + * @op: the io_uring opcode + * + * This is similar to audit_syscall_entry() but is intended for use by io_uring + * operations. This function should only ever be called from + * audit_uring_entry() as we rely on the audit context checking present in that + * function. + */ +void __audit_uring_entry(u8 op) +{ + struct audit_context *ctx = audit_context(); + + if (ctx->state == AUDIT_STATE_DISABLED) + return; + + /* + * NOTE: It's possible that we can be called from the process' context + * before it returns to userspace, and before audit_syscall_exit() + * is called. In this case there is not much to do, just record + * the io_uring details and return. + */ + ctx->uring_op = op; + if (ctx->context == AUDIT_CTX_SYSCALL) + return; + + ctx->dummy = !audit_n_rules; + if (!ctx->dummy && ctx->state == AUDIT_STATE_BUILD) + ctx->prio = 0; + + ctx->context = AUDIT_CTX_URING; + ctx->current_state = ctx->state; + ktime_get_coarse_real_ts64(&ctx->ctime); +} + +/** + * __audit_uring_exit - wrap up the kernel task's audit context after io_uring + * @success: true/false value to indicate if the operation succeeded or not + * @code: operation return code + * + * This is similar to audit_syscall_exit() but is intended for use by io_uring + * operations. This function should only ever be called from + * audit_uring_exit() as we rely on the audit context checking present in that + * function. + */ +void __audit_uring_exit(int success, long code) +{ + struct audit_context *ctx = audit_context(); + + /* + * TODO: At some point we will likely want to filter on io_uring ops + * and other things similar to what we do for syscalls, but that + * is something for another day; just record what we can here. + */ + + if (ctx->context == AUDIT_CTX_SYSCALL) { + /* + * NOTE: See the note in __audit_uring_entry() about the case + * where we may be called from process context before we + * return to userspace via audit_syscall_exit(). In this + * case we simply emit a URINGOP record and bail, the + * normal syscall exit handling will take care of + * everything else. + * It is also worth mentioning that when we are called, + * the current process creds may differ from the creds + * used during the normal syscall processing; keep that + * in mind if/when we move the record generation code. + */ + + /* + * We need to filter on the syscall info here to decide if we + * should emit a URINGOP record. I know it seems odd but this + * solves the problem where users have a filter to block *all* + * syscall records in the "exit" filter; we want to preserve + * the behavior here. + */ + audit_filter_syscall(current, ctx); + audit_filter_inodes(current, ctx); + if (ctx->current_state != AUDIT_STATE_RECORD) + return; + + audit_log_uring(ctx); + return; + } + + /* this may generate CONFIG_CHANGE records */ + if (!list_empty(&ctx->killed_trees)) + audit_kill_trees(ctx); + + audit_filter_inodes(current, ctx); + if (ctx->current_state != AUDIT_STATE_RECORD) + goto out; + audit_return_fixup(ctx, success, code); + audit_log_exit(); + +out: + audit_reset_context(ctx); +} + /** * __audit_syscall_entry - fill in an audit record at syscall entry * @major: major syscall type (function) From patchwork Wed Sep 15 16:49:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Moore X-Patchwork-Id: 12496865 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CF17EC433EF for ; Wed, 15 Sep 2021 16:49:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B95B4610E9 for ; Wed, 15 Sep 2021 16:49:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229489AbhIOQvC (ORCPT ); Wed, 15 Sep 2021 12:51:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36488 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230030AbhIOQu7 (ORCPT ); Wed, 15 Sep 2021 12:50:59 -0400 Received: from mail-qk1-x729.google.com (mail-qk1-x729.google.com [IPv6:2607:f8b0:4864:20::729]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C88BC061767 for ; Wed, 15 Sep 2021 09:49:40 -0700 (PDT) Received: by mail-qk1-x729.google.com with SMTP id 22so4161146qkg.2 for ; Wed, 15 Sep 2021 09:49:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=paul-moore-com.20150623.gappssmtp.com; s=20150623; h=subject:from:to:date:message-id:in-reply-to:references:user-agent :mime-version:content-transfer-encoding; bh=WRpSFXwugVJ8UJTyRzjrpsRt+omqQhBN40RZHAMdMWg=; b=YFT5bLDYtu/N6jz/ZLAgJxZYxIoJAxV8bwBT8c95fe89PYxrogbySQNd1UvgWXoTo7 ljr9sbz4tzyOkD1tpQACsJzylaizP2GNrNGP8wtIwtoXfwGv43buD4+TGALjojVMCyVr WB95C9JwgLZV48xVqvuQRIlBzbLH9TJDyHediY54eOiKJTHbQoL0IN+kCTG51dmQ6MUP WSrTrYVvZrn/XnUWom9ECjQjfGc/rAcIlCCVN19QRCkwxjKuqy+QCt8+jGZhQKFZZnl2 9Ep3EOHR0EjlZR50cuehSNfSevC5p5GlhwRCQYx+1HjJu4qu0wbXElB3QvlJ4QZOKLiQ 9hvQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:from:to:date:message-id:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=WRpSFXwugVJ8UJTyRzjrpsRt+omqQhBN40RZHAMdMWg=; b=ed0BKjkSZYiRqdd2bH533s52eexbJloT0he8UuZWMvQsc2nSZblxFWqCVXTNUvFJtV g1OwGMoDCGa4Ody7BRFplaItpQScsEr7HMw+fXOReQx4ov9JJ6/jMTdnRl9/BN/8acZP yCH9kCpVXvjuTkwTSGUpMXuMmZZ2JpZO4oPDpCHjQ/AxohOz+KHQeJ/ZjmIRUjONitdE ygKws4DegA72FonrO9EzxxRlfjdCYiyep5CxEMB0A3+ZrVhJegWqhEcpRhqoiaYGMr7/ aI65JpW43lIpD/d31+BnaSHa366cT3x3NuVjwjYyPDRvZgGsGmDUzTWFkrVE6lhHN8Bs PNBQ== X-Gm-Message-State: AOAM5321vTAqNcpNk+UKvJAUETfVC0UEeNfoi1phjz66OCBGIl3qX4Ta p/GBNbWuOWlCp3TAql7Mi1rHE3XsLxnB X-Google-Smtp-Source: ABdhPJzalZf+bJ7CI7N5NPv8PiOiHGdrjocaNEZEftoIUvoOjtE3QTLYZObi+fc3gAP5fAWYKT3e+w== X-Received: by 2002:a05:620a:159a:: with SMTP id d26mr861371qkk.399.1631724578758; Wed, 15 Sep 2021 09:49:38 -0700 (PDT) Received: from localhost (pool-96-237-52-188.bstnma.fios.verizon.net. [96.237.52.188]) by smtp.gmail.com with ESMTPSA id w20sm310746qtj.72.2021.09.15.09.49.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Sep 2021 09:49:38 -0700 (PDT) Subject: [PATCH v4 3/8] audit: add filtering for io_uring records From: Paul Moore To: linux-security-module@vger.kernel.org, selinux@vger.kernel.org, linux-audit@redhat.com, io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jens Axboe , Pavel Begunkov , Kumar Kartikeya Dwivedi Date: Wed, 15 Sep 2021 12:49:37 -0400 Message-ID: <163172457764.88001.5016839648172573823.stgit@olly> In-Reply-To: <163172413301.88001.16054830862146685573.stgit@olly> References: <163172413301.88001.16054830862146685573.stgit@olly> User-Agent: StGit/1.1 MIME-Version: 1.0 Precedence: bulk List-ID: This patch adds basic audit io_uring filtering, using as much of the existing audit filtering infrastructure as possible. In order to do this we reuse the audit filter rule's syscall mask for the io_uring operation and we create a new filter for io_uring operations as AUDIT_FILTER_URING_EXIT/audit_filter_list[7]. Thanks to Richard Guy Briggs for his review, feedback, and work on the corresponding audit userspace changes. Signed-off-by: Paul Moore Acked-by: Richard Guy Briggs --- v4: - no change v3: - removed work-in-progress warning from the description v2: - incorporate feedback from Richard v1: - initial draft --- include/uapi/linux/audit.h | 3 +- kernel/audit_tree.c | 3 +- kernel/audit_watch.c | 3 +- kernel/auditfilter.c | 15 +++++++++-- kernel/auditsc.c | 61 ++++++++++++++++++++++++++++++++++---------- 5 files changed, 65 insertions(+), 20 deletions(-) diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h index a1997697c8b1..ecf1edd2affa 100644 --- a/include/uapi/linux/audit.h +++ b/include/uapi/linux/audit.h @@ -167,8 +167,9 @@ #define AUDIT_FILTER_EXCLUDE 0x05 /* Apply rule before record creation */ #define AUDIT_FILTER_TYPE AUDIT_FILTER_EXCLUDE /* obsolete misleading naming */ #define AUDIT_FILTER_FS 0x06 /* Apply rule at __audit_inode_child */ +#define AUDIT_FILTER_URING_EXIT 0x07 /* Apply rule at io_uring op exit */ -#define AUDIT_NR_FILTERS 7 +#define AUDIT_NR_FILTERS 8 #define AUDIT_FILTER_PREPEND 0x10 /* Prepend to front of list */ diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c index 2cd7b5694422..338c53a961c5 100644 --- a/kernel/audit_tree.c +++ b/kernel/audit_tree.c @@ -726,7 +726,8 @@ int audit_make_tree(struct audit_krule *rule, char *pathname, u32 op) { if (pathname[0] != '/' || - rule->listnr != AUDIT_FILTER_EXIT || + (rule->listnr != AUDIT_FILTER_EXIT && + rule->listnr != AUDIT_FILTER_URING_EXIT) || op != Audit_equal || rule->inode_f || rule->watch || rule->tree) return -EINVAL; diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c index 2acf7ca49154..698b62b4a2ec 100644 --- a/kernel/audit_watch.c +++ b/kernel/audit_watch.c @@ -183,7 +183,8 @@ int audit_to_watch(struct audit_krule *krule, char *path, int len, u32 op) return -EOPNOTSUPP; if (path[0] != '/' || path[len-1] == '/' || - krule->listnr != AUDIT_FILTER_EXIT || + (krule->listnr != AUDIT_FILTER_EXIT && + krule->listnr != AUDIT_FILTER_URING_EXIT) || op != Audit_equal || krule->inode_f || krule->watch || krule->tree) return -EINVAL; diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c index db2c6b59dfc3..d75acb014ccd 100644 --- a/kernel/auditfilter.c +++ b/kernel/auditfilter.c @@ -44,7 +44,8 @@ struct list_head audit_filter_list[AUDIT_NR_FILTERS] = { LIST_HEAD_INIT(audit_filter_list[4]), LIST_HEAD_INIT(audit_filter_list[5]), LIST_HEAD_INIT(audit_filter_list[6]), -#if AUDIT_NR_FILTERS != 7 + LIST_HEAD_INIT(audit_filter_list[7]), +#if AUDIT_NR_FILTERS != 8 #error Fix audit_filter_list initialiser #endif }; @@ -56,6 +57,7 @@ static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = { LIST_HEAD_INIT(audit_rules_list[4]), LIST_HEAD_INIT(audit_rules_list[5]), LIST_HEAD_INIT(audit_rules_list[6]), + LIST_HEAD_INIT(audit_rules_list[7]), }; DEFINE_MUTEX(audit_filter_mutex); @@ -151,7 +153,8 @@ char *audit_unpack_string(void **bufp, size_t *remain, size_t len) static inline int audit_to_inode(struct audit_krule *krule, struct audit_field *f) { - if (krule->listnr != AUDIT_FILTER_EXIT || + if ((krule->listnr != AUDIT_FILTER_EXIT && + krule->listnr != AUDIT_FILTER_URING_EXIT) || krule->inode_f || krule->watch || krule->tree || (f->op != Audit_equal && f->op != Audit_not_equal)) return -EINVAL; @@ -248,6 +251,7 @@ static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data * pr_err("AUDIT_FILTER_ENTRY is deprecated\n"); goto exit_err; case AUDIT_FILTER_EXIT: + case AUDIT_FILTER_URING_EXIT: case AUDIT_FILTER_TASK: #endif case AUDIT_FILTER_USER: @@ -332,6 +336,10 @@ static int audit_field_valid(struct audit_entry *entry, struct audit_field *f) if (entry->rule.listnr != AUDIT_FILTER_FS) return -EINVAL; break; + case AUDIT_PERM: + if (entry->rule.listnr == AUDIT_FILTER_URING_EXIT) + return -EINVAL; + break; } switch (entry->rule.listnr) { @@ -980,7 +988,8 @@ static inline int audit_add_rule(struct audit_entry *entry) } entry->rule.prio = ~0ULL; - if (entry->rule.listnr == AUDIT_FILTER_EXIT) { + if (entry->rule.listnr == AUDIT_FILTER_EXIT || + entry->rule.listnr == AUDIT_FILTER_URING_EXIT) { if (entry->rule.flags & AUDIT_FILTER_PREPEND) entry->rule.prio = ++prio_high; else diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 6dda448fb826..7c66a9fea5e6 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -805,6 +805,35 @@ static int audit_in_mask(const struct audit_krule *rule, unsigned long val) return rule->mask[word] & bit; } +/** + * audit_filter_uring - apply filters to an io_uring operation + * @tsk: associated task + * @ctx: audit context + */ +static void audit_filter_uring(struct task_struct *tsk, + struct audit_context *ctx) +{ + struct audit_entry *e; + enum audit_state state; + + if (auditd_test_task(tsk)) + return; + + rcu_read_lock(); + list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_URING_EXIT], + list) { + if (audit_in_mask(&e->rule, ctx->uring_op) && + audit_filter_rules(tsk, &e->rule, ctx, NULL, &state, + false)) { + rcu_read_unlock(); + ctx->current_state = state; + return; + } + } + rcu_read_unlock(); + return; +} + /* At syscall exit time, this filter is called if the audit_state is * not low enough that auditing cannot take place, but is also not * high enough that we already know we have to write an audit record @@ -1757,7 +1786,7 @@ static void audit_log_exit(void) * __audit_free - free a per-task audit context * @tsk: task whose audit context block to free * - * Called from copy_process and do_exit + * Called from copy_process, do_exit, and the io_uring code */ void __audit_free(struct task_struct *tsk) { @@ -1775,15 +1804,21 @@ void __audit_free(struct task_struct *tsk) * random task_struct that doesn't doesn't have any meaningful data we * need to log via audit_log_exit(). */ - if (tsk == current && !context->dummy && - context->context == AUDIT_CTX_SYSCALL) { + if (tsk == current && !context->dummy) { context->return_valid = AUDITSC_INVALID; context->return_code = 0; - - audit_filter_syscall(tsk, context); - audit_filter_inodes(tsk, context); - if (context->current_state == AUDIT_STATE_RECORD) - audit_log_exit(); + if (context->context == AUDIT_CTX_SYSCALL) { + audit_filter_syscall(tsk, context); + audit_filter_inodes(tsk, context); + if (context->current_state == AUDIT_STATE_RECORD) + audit_log_exit(); + } else if (context->context == AUDIT_CTX_URING) { + /* TODO: verify this case is real and valid */ + audit_filter_uring(tsk, context); + audit_filter_inodes(tsk, context); + if (context->current_state == AUDIT_STATE_RECORD) + audit_log_uring(context); + } } audit_set_context(tsk, NULL); @@ -1867,12 +1902,6 @@ void __audit_uring_exit(int success, long code) { struct audit_context *ctx = audit_context(); - /* - * TODO: At some point we will likely want to filter on io_uring ops - * and other things similar to what we do for syscalls, but that - * is something for another day; just record what we can here. - */ - if (ctx->context == AUDIT_CTX_SYSCALL) { /* * NOTE: See the note in __audit_uring_entry() about the case @@ -1895,6 +1924,8 @@ void __audit_uring_exit(int success, long code) * the behavior here. */ audit_filter_syscall(current, ctx); + if (ctx->current_state != AUDIT_STATE_RECORD) + audit_filter_uring(current, ctx); audit_filter_inodes(current, ctx); if (ctx->current_state != AUDIT_STATE_RECORD) return; @@ -1907,6 +1938,8 @@ void __audit_uring_exit(int success, long code) if (!list_empty(&ctx->killed_trees)) audit_kill_trees(ctx); + /* run through both filters to ensure we set the filterkey properly */ + audit_filter_uring(current, ctx); audit_filter_inodes(current, ctx); if (ctx->current_state != AUDIT_STATE_RECORD) goto out; From patchwork Wed Sep 15 16:49:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Paul Moore X-Patchwork-Id: 12496867 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE4DFC433FE for ; Wed, 15 Sep 2021 16:49:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B587A6113E for ; Wed, 15 Sep 2021 16:49:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229812AbhIOQvI (ORCPT ); Wed, 15 Sep 2021 12:51:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36532 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229702AbhIOQvF (ORCPT ); Wed, 15 Sep 2021 12:51:05 -0400 Received: from mail-qv1-xf2a.google.com (mail-qv1-xf2a.google.com [IPv6:2607:f8b0:4864:20::f2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 21503C061767 for ; Wed, 15 Sep 2021 09:49:46 -0700 (PDT) Received: by mail-qv1-xf2a.google.com with SMTP id di6so2294222qvb.1 for ; Wed, 15 Sep 2021 09:49:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=paul-moore-com.20150623.gappssmtp.com; s=20150623; h=subject:from:to:date:message-id:in-reply-to:references:user-agent :mime-version:content-transfer-encoding; bh=Y1TkJrYx+ov8z66ALV7f2Sg5s1JjZX16Pw/yL09jGtA=; b=MOUBXl8jVr3QXSJbfF+JqSmSkyrC2sjFL9Mgn1PEPX2Ucq9xMq7Ym6t9beKr3oLpUC t8gjfU+RE6wjzifXOKbYF/LaSZCRbnIiYcQC0FAOmqnMJRQhBO9+OapXZnpgDmOy/80n jQ+0wm+8FccsibXplvv+t5+ew0QksmeyH2Co7yzsUtnM6PPwOdb0+HLGW2Xu9uMWmdCM jZsG9Rdul9sLY1XUby2wOGkDCIRpcP2KW1dE7Tyh1XXcoRT1V8ukuinqYkSDbVoS786m lgFvCGlVL/HN/tQcxv5Pm6Nwf6B0mpgkuUble2HHmKTK2bjB1UuyZQ+KpbCFaCrnl2r+ QdIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:from:to:date:message-id:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=Y1TkJrYx+ov8z66ALV7f2Sg5s1JjZX16Pw/yL09jGtA=; b=F7NPEWXo5pBCxcX9SuSdwDIbmzU/lhBBjffxKnB6gpdv2w7biBgidqjCUcY7gUmctl u8r2Q/bc6Tjpc/r2M+rg7i4o/k6Iqzn/r4yjAUfeA131Z2i4fzo6+9MYxdTLMU8gAhZd yx0a+P5XeV4R63y/MekgVLdOcYcIxS7ye9kCkZD8/q+vJ25PrgTDTSqMaBGfbKu2o5S3 SWZo7cJnKfhpER/nmUPLyxRESAXz+F6ICfymugeYTj14ENhVRrs0x+GV3jT+/LKHeA+n W6GZCF042OfmFLC5YY9lEIX+DilsiRFCEf3Q/9hcfS3x4aYORNehU85yftgXpiGzPFGR maVQ== X-Gm-Message-State: AOAM532iqGqF004F2NIxF3UUIds6H6D4De5LJtaoBZVhzu6UnYK699uQ Z0KBNNljhBeQn9VCdn3xlyXGI8xnn1K9 X-Google-Smtp-Source: ABdhPJzkEEdLdy0cmCrWtOnT2Cl0+J/Y8K0llmm4G08TjUGg5mP2ZlZheVR6JwnNE/XlH+vcZDoLOg== X-Received: by 2002:ad4:54ce:: with SMTP id j14mr653905qvx.32.1631724584929; Wed, 15 Sep 2021 09:49:44 -0700 (PDT) Received: from localhost (pool-96-237-52-188.bstnma.fios.verizon.net. [96.237.52.188]) by smtp.gmail.com with ESMTPSA id g12sm268749qtq.92.2021.09.15.09.49.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Sep 2021 09:49:44 -0700 (PDT) Subject: [PATCH v4 4/8] fs: add anon_inode_getfile_secure() similar to anon_inode_getfd_secure() From: Paul Moore To: linux-security-module@vger.kernel.org, selinux@vger.kernel.org, linux-audit@redhat.com, io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jens Axboe , Pavel Begunkov , Kumar Kartikeya Dwivedi Date: Wed, 15 Sep 2021 12:49:43 -0400 Message-ID: <163172458385.88001.9452390680679491195.stgit@olly> In-Reply-To: <163172413301.88001.16054830862146685573.stgit@olly> References: <163172413301.88001.16054830862146685573.stgit@olly> User-Agent: StGit/1.1 MIME-Version: 1.0 Precedence: bulk List-ID: Extending the secure anonymous inode support to other subsystems requires that we have a secure anon_inode_getfile() variant in addition to the existing secure anon_inode_getfd() variant. Thankfully we can reuse the existing __anon_inode_getfile() function and just wrap it with the proper arguments. Acked-by: Mickaël Salaün Signed-off-by: Paul Moore --- v4: - no change v3: - no change v2: - no change v1: - initial draft --- fs/anon_inodes.c | 29 +++++++++++++++++++++++++++++ include/linux/anon_inodes.h | 4 ++++ 2 files changed, 33 insertions(+) diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c index a280156138ed..e0c3e33c4177 100644 --- a/fs/anon_inodes.c +++ b/fs/anon_inodes.c @@ -148,6 +148,35 @@ struct file *anon_inode_getfile(const char *name, } EXPORT_SYMBOL_GPL(anon_inode_getfile); +/** + * anon_inode_getfile_secure - Like anon_inode_getfile(), but creates a new + * !S_PRIVATE anon inode rather than reuse the + * singleton anon inode and calls the + * inode_init_security_anon() LSM hook. This + * allows for both the inode to have its own + * security context and for the LSM to enforce + * policy on the inode's creation. + * + * @name: [in] name of the "class" of the new file + * @fops: [in] file operations for the new file + * @priv: [in] private data for the new file (will be file's private_data) + * @flags: [in] flags + * @context_inode: + * [in] the logical relationship with the new inode (optional) + * + * The LSM may use @context_inode in inode_init_security_anon(), but a + * reference to it is not held. Returns the newly created file* or an error + * pointer. See the anon_inode_getfile() documentation for more information. + */ +struct file *anon_inode_getfile_secure(const char *name, + const struct file_operations *fops, + void *priv, int flags, + const struct inode *context_inode) +{ + return __anon_inode_getfile(name, fops, priv, flags, + context_inode, true); +} + static int __anon_inode_getfd(const char *name, const struct file_operations *fops, void *priv, int flags, diff --git a/include/linux/anon_inodes.h b/include/linux/anon_inodes.h index 71881a2b6f78..5deaddbd7927 100644 --- a/include/linux/anon_inodes.h +++ b/include/linux/anon_inodes.h @@ -15,6 +15,10 @@ struct inode; struct file *anon_inode_getfile(const char *name, const struct file_operations *fops, void *priv, int flags); +struct file *anon_inode_getfile_secure(const char *name, + const struct file_operations *fops, + void *priv, int flags, + const struct inode *context_inode); int anon_inode_getfd(const char *name, const struct file_operations *fops, void *priv, int flags); int anon_inode_getfd_secure(const char *name, From patchwork Wed Sep 15 16:49:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Moore X-Patchwork-Id: 12496869 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A66FDC4332F for ; Wed, 15 Sep 2021 16:49:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9226261244 for ; Wed, 15 Sep 2021 16:49:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229702AbhIOQvL (ORCPT ); Wed, 15 Sep 2021 12:51:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36564 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230016AbhIOQvL (ORCPT ); Wed, 15 Sep 2021 12:51:11 -0400 Received: from mail-qv1-xf30.google.com (mail-qv1-xf30.google.com [IPv6:2607:f8b0:4864:20::f30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 44645C061766 for ; Wed, 15 Sep 2021 09:49:52 -0700 (PDT) Received: by mail-qv1-xf30.google.com with SMTP id 62so2253874qvb.11 for ; Wed, 15 Sep 2021 09:49:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=paul-moore-com.20150623.gappssmtp.com; s=20150623; h=subject:from:to:date:message-id:in-reply-to:references:user-agent :mime-version:content-transfer-encoding; bh=osh6NDovzw+ZlXVVDOUZQCSNWZPxEeXF/7ss3wLmtKA=; b=Kv3Vj3lzxRAZJd4JPCmdm40i8ty++ilePqyolEIaYhWs/o1fsLgK9efzsYW3QiD44f dms6SjJGKaaKHs5OrsE76GSk9SUZrOJOg2mfde7/vQWKTyEz//5FOYazl86x/k86H2C6 pzSGsuPJS5TY7ow0hCZY8At/mH1zfcz9x2lMbZZv0wNu4qOMGmSvlpuS9syvXWZ5LXaQ B45Xuz4AEHia38q0cLJVHdWqua3pPkdy/WV5G73xpcRw10OAj3hTWZsZruIDq3lw2LcJ bcsQhdDmLYW2sDUkqGKpMu6lvkXH8yTosOklEuX7aKMxuwyUPplAbFpqOH6/IyvPuTOJ b2eQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:from:to:date:message-id:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=osh6NDovzw+ZlXVVDOUZQCSNWZPxEeXF/7ss3wLmtKA=; b=KCePFk9gG5/GvdB6dumQe64zPPS/tGON72OOd1xxXnaznaN4IhQ8sx1gn17edYn4PU trGU4vYBgcaFo38VGfQESRmIAk/SFwilwRx+xQR9PVMApEwUWW3hDifStbVMx3Iem35p L548Qg0PhBu0CikCknj1f4IdxwJsHFt5zjQg/VOcmCVMEfGJLS3hunhNap/whFoWZTtl mLfTOJwYC55RkyHt09LH3UI2fxdP7ofjjBNrc0PwN/V0/f8lqjpCr6S7rFkDclKP78TU iVoZSVyZKIFDuBO5gYNKLOQYdGHb2YuL/80AWcTN8PPzXQ8dACp0a7QTyXWzJ2p0NJnD WrUQ== X-Gm-Message-State: AOAM532qgjoyT8roolOLu5ltzCtPNaJpyuvsGFBkSNPr9ohxgpNnel1x NS2MdlJ3YTs7i/3lJ2c51S23EcHsGSx2 X-Google-Smtp-Source: ABdhPJyL+cxrJfyT+g4h6UtkmldJivzlVA9vPqio5LiheuUJzccqirZH/QPK9x2hW9PO0FHnZb0Duw== X-Received: by 2002:a05:6214:11f0:: with SMTP id e16mr650335qvu.30.1631724591078; Wed, 15 Sep 2021 09:49:51 -0700 (PDT) Received: from localhost (pool-96-237-52-188.bstnma.fios.verizon.net. [96.237.52.188]) by smtp.gmail.com with ESMTPSA id h9sm390273qkl.4.2021.09.15.09.49.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Sep 2021 09:49:50 -0700 (PDT) Subject: [PATCH v4 5/8] io_uring: convert io_uring to the secure anon inode interface From: Paul Moore To: linux-security-module@vger.kernel.org, selinux@vger.kernel.org, linux-audit@redhat.com, io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jens Axboe , Pavel Begunkov , Kumar Kartikeya Dwivedi Date: Wed, 15 Sep 2021 12:49:50 -0400 Message-ID: <163172459001.88001.17463922586800990358.stgit@olly> In-Reply-To: <163172413301.88001.16054830862146685573.stgit@olly> References: <163172413301.88001.16054830862146685573.stgit@olly> User-Agent: StGit/1.1 MIME-Version: 1.0 Precedence: bulk List-ID: Converting io_uring's anonymous inode to the secure anon inode API enables LSMs to enforce policy on the io_uring anonymous inodes if they chose to do so. This is an important first step towards providing the necessary mechanisms so that LSMs can apply security policy to io_uring operations. Signed-off-by: Paul Moore --- v4: - no change v3: - no change v2: - no change v1: - initial draft --- fs/io_uring.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 388754b24785..56cc9aba0d01 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -10155,8 +10155,8 @@ static struct file *io_uring_get_file(struct io_ring_ctx *ctx) return ERR_PTR(ret); #endif - file = anon_inode_getfile("[io_uring]", &io_uring_fops, ctx, - O_RDWR | O_CLOEXEC); + file = anon_inode_getfile_secure("[io_uring]", &io_uring_fops, ctx, + O_RDWR | O_CLOEXEC, NULL); #if defined(CONFIG_UNIX) if (IS_ERR(file)) { sock_release(ctx->ring_sock); From patchwork Wed Sep 15 16:49:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Moore X-Patchwork-Id: 12496871 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D8AD0C43219 for ; Wed, 15 Sep 2021 16:49:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C30C1610E9 for ; Wed, 15 Sep 2021 16:49:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230361AbhIOQvS (ORCPT ); Wed, 15 Sep 2021 12:51:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36604 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230264AbhIOQvR (ORCPT ); Wed, 15 Sep 2021 12:51:17 -0400 Received: from mail-qt1-x832.google.com (mail-qt1-x832.google.com [IPv6:2607:f8b0:4864:20::832]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6BEA6C061766 for ; Wed, 15 Sep 2021 09:49:58 -0700 (PDT) Received: by mail-qt1-x832.google.com with SMTP id s32so2864858qtc.12 for ; Wed, 15 Sep 2021 09:49:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=paul-moore-com.20150623.gappssmtp.com; s=20150623; h=subject:from:to:date:message-id:in-reply-to:references:user-agent :mime-version:content-transfer-encoding; bh=ICAM6mKHGGedHsxpsbavLoCbX1CIysyavsIH2Q+N0Do=; b=KKF14JOkrMrQgNum+nBeUR/4lPbLyAGCyUz8uvN64BHpfDHhpdKb75itIdh7iz0u5W yy0vBoP38CXT8ebj9sARJYQcTaG2aHHvlfDtCFgzZnYAWNIb+7Q108a7ebdBZDFmR5wm DWfHYRW/s1dz7O2P99j5kYeG/F/QvtVB1M2OQb4DEHbVcMmAeh5gAIjKXBrSqQfm8baq gUxfW2T7TeKDhBeQPUyhGLpcdUt5nXSPhqrj4rMRFmim1QF+1Hl2EKGj51B0Gro94V3G +RSL60y6hTMdpg59rqvhAL5XU0I93HiUe/LxGaNivNfbCqrPorEnZZsvUK2M4R22Pav5 6Wsg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:from:to:date:message-id:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=ICAM6mKHGGedHsxpsbavLoCbX1CIysyavsIH2Q+N0Do=; b=XtjPZzU6L/ykoYYdcdNzZ/bk3PwalgWxoDr578WPI+dY4p451wbxITBK3EJOREuKJR MPWbHMBYaF5FjF+4Vr5ZT9LU2qsISN/qHWaOUfKmJLjcsHwHqjtw+PHGsb7BrgovjgTY 4nAIZv6a8X/aZCRa8R5/z3sY2Jfkj1Vn+QAtEMjPDODpANxuf8+CPsjm/1PgdzGnOXPw HEgn5fd7ZmtTWimtuiwHC8mQFeHTeHR5CezNJgU7h0cYG7cbuv24hrTc+ALwUhftIEm2 PzGNq1OxjISSEPNfyPIJhm68Kq4UDt1LvaseOYFladqr0fwg6AMeMOj+WL0XwQu86EpQ SWag== X-Gm-Message-State: AOAM533RbiHVXgLaIgw648roHJlYJOkIWGanhyAQEiGerIcbh1VQ78av 9TPUnKpMtI7Ak1b1pv7zZgGp6unV9nPr X-Google-Smtp-Source: ABdhPJyhq6uYSCuyukRnCV8KXX6viIqp20hFzF32qPgkImdooiMPdvSk1VaBXD5ejImpgMFtWIgfYA== X-Received: by 2002:ac8:5c95:: with SMTP id r21mr788423qta.57.1631724597210; Wed, 15 Sep 2021 09:49:57 -0700 (PDT) Received: from localhost (pool-96-237-52-188.bstnma.fios.verizon.net. [96.237.52.188]) by smtp.gmail.com with ESMTPSA id x21sm365217qkf.76.2021.09.15.09.49.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Sep 2021 09:49:56 -0700 (PDT) Subject: [PATCH v4 6/8] lsm,io_uring: add LSM hooks to io_uring From: Paul Moore To: linux-security-module@vger.kernel.org, selinux@vger.kernel.org, linux-audit@redhat.com, io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jens Axboe , Pavel Begunkov , Kumar Kartikeya Dwivedi Date: Wed, 15 Sep 2021 12:49:56 -0400 Message-ID: <163172459614.88001.11338111737517016751.stgit@olly> In-Reply-To: <163172413301.88001.16054830862146685573.stgit@olly> References: <163172413301.88001.16054830862146685573.stgit@olly> User-Agent: StGit/1.1 MIME-Version: 1.0 Precedence: bulk List-ID: A full expalantion of io_uring is beyond the scope of this commit description, but in summary it is an asynchronous I/O mechanism which allows for I/O requests and the resulting data to be queued in memory mapped "rings" which are shared between the kernel and userspace. Optionally, io_uring offers the ability for applications to spawn kernel threads to dequeue I/O requests from the ring and submit the requests in the kernel, helping to minimize the syscall overhead. Rings are accessed in userspace by memory mapping a file descriptor provided by the io_uring_setup(2), and can be shared between applications as one might do with any open file descriptor. Finally, process credentials can be registered with a given ring and any process with access to that ring can submit I/O requests using any of the registered credentials. While the io_uring functionality is widely recognized as offering a vastly improved, and high performing asynchronous I/O mechanism, its ability to allow processes to submit I/O requests with credentials other than its own presents a challenge to LSMs. When a process creates a new io_uring ring the ring's credentials are inhertied from the calling process; if this ring is shared with another process operating with different credentials there is the potential to bypass the LSMs security policy. Similarly, registering credentials with a given ring allows any process with access to that ring to submit I/O requests with those credentials. In an effort to allow LSMs to apply security policy to io_uring I/O operations, this patch adds two new LSM hooks. These hooks, in conjunction with the LSM anonymous inode support previously submitted, allow an LSM to apply access control policy to the sharing of io_uring rings as well as any io_uring credential changes requested by a process. The new LSM hooks are described below: * int security_uring_override_creds(cred) Controls if the current task, executing an io_uring operation, is allowed to override it's credentials with @cred. In cases where the current task is a user application, the current credentials will be those of the user application. In cases where the current task is a kernel thread servicing io_uring requests the current credentials will be those of the io_uring ring (inherited from the process that created the ring). * int security_uring_sqpoll(void) Controls if the current task is allowed to create an io_uring polling thread (IORING_SETUP_SQPOLL). Without a SQPOLL thread in the kernel processes must submit I/O requests via io_uring_enter(2) which allows us to compare any requested credential changes against the application making the request. With a SQPOLL thread, we can no longer compare requested credential changes against the application making the request, the comparison is made against the ring's credentials. Signed-off-by: Paul Moore --- v4: - no change v3: - removed work-in-progress warning from the description v2: - no change v1: - initial draft --- fs/io_uring.c | 10 ++++++++++ include/linux/lsm_hook_defs.h | 5 +++++ include/linux/lsm_hooks.h | 13 +++++++++++++ include/linux/security.h | 16 ++++++++++++++++ security/security.c | 12 ++++++++++++ 5 files changed, 56 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index 56cc9aba0d01..f89d00af3a67 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -80,6 +80,7 @@ #include #include #include +#include #define CREATE_TRACE_POINTS #include @@ -7070,6 +7071,11 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, if (!req->creds) return -EINVAL; get_cred(req->creds); + ret = security_uring_override_creds(req->creds); + if (ret) { + put_cred(req->creds); + return ret; + } req->flags |= REQ_F_CREDS; } state = &ctx->submit_state; @@ -8566,6 +8572,10 @@ static int io_sq_offload_create(struct io_ring_ctx *ctx, struct io_sq_data *sqd; bool attached; + ret = security_uring_sqpoll(); + if (ret) + return ret; + sqd = io_get_sq_data(p, &attached); if (IS_ERR(sqd)) { ret = PTR_ERR(sqd); diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 2adeea44c0d5..b3c525353769 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -402,3 +402,8 @@ LSM_HOOK(void, LSM_RET_VOID, perf_event_free, struct perf_event *event) LSM_HOOK(int, 0, perf_event_read, struct perf_event *event) LSM_HOOK(int, 0, perf_event_write, struct perf_event *event) #endif /* CONFIG_PERF_EVENTS */ + +#ifdef CONFIG_IO_URING +LSM_HOOK(int, 0, uring_override_creds, const struct cred *new) +LSM_HOOK(int, 0, uring_sqpoll, void) +#endif /* CONFIG_IO_URING */ diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 5c4c5c0602cb..0eb0ae95c4c4 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -1557,6 +1557,19 @@ * Read perf_event security info if allowed. * @perf_event_write: * Write perf_event security info if allowed. + * + * Security hooks for io_uring + * + * @uring_override_creds: + * Check if the current task, executing an io_uring operation, is allowed + * to override it's credentials with @new. + * + * @new: the new creds to use + * + * @uring_sqpoll: + * Check whether the current task is allowed to spawn a io_uring polling + * thread (IORING_SETUP_SQPOLL). + * */ union security_list_options { #define LSM_HOOK(RET, DEFAULT, NAME, ...) RET (*NAME)(__VA_ARGS__); diff --git a/include/linux/security.h b/include/linux/security.h index 5b7288521300..7979b9629a42 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -2038,4 +2038,20 @@ static inline int security_perf_event_write(struct perf_event *event) #endif /* CONFIG_SECURITY */ #endif /* CONFIG_PERF_EVENTS */ +#ifdef CONFIG_IO_URING +#ifdef CONFIG_SECURITY +extern int security_uring_override_creds(const struct cred *new); +extern int security_uring_sqpoll(void); +#else +static inline int security_uring_override_creds(const struct cred *new) +{ + return 0; +} +static inline int security_uring_sqpoll(void) +{ + return 0; +} +#endif /* CONFIG_SECURITY */ +#endif /* CONFIG_IO_URING */ + #endif /* ! __LINUX_SECURITY_H */ diff --git a/security/security.c b/security/security.c index 9ffa9e9c5c55..c49a2c0cc1c1 100644 --- a/security/security.c +++ b/security/security.c @@ -2625,3 +2625,15 @@ int security_perf_event_write(struct perf_event *event) return call_int_hook(perf_event_write, 0, event); } #endif /* CONFIG_PERF_EVENTS */ + +#ifdef CONFIG_IO_URING +int security_uring_override_creds(const struct cred *new) +{ + return call_int_hook(uring_override_creds, 0, new); +} + +int security_uring_sqpoll(void) +{ + return call_int_hook(uring_sqpoll, 0); +} +#endif /* CONFIG_IO_URING */ From patchwork Wed Sep 15 16:50:02 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Moore X-Patchwork-Id: 12496873 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A8125C43219 for ; Wed, 15 Sep 2021 16:50:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9603261247 for ; Wed, 15 Sep 2021 16:50:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230377AbhIOQv1 (ORCPT ); Wed, 15 Sep 2021 12:51:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36654 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230439AbhIOQv0 (ORCPT ); Wed, 15 Sep 2021 12:51:26 -0400 Received: from mail-qt1-x835.google.com (mail-qt1-x835.google.com [IPv6:2607:f8b0:4864:20::835]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 97A63C0613D8 for ; Wed, 15 Sep 2021 09:50:04 -0700 (PDT) Received: by mail-qt1-x835.google.com with SMTP id u4so2921484qta.2 for ; Wed, 15 Sep 2021 09:50:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=paul-moore-com.20150623.gappssmtp.com; s=20150623; h=subject:from:to:date:message-id:in-reply-to:references:user-agent :mime-version:content-transfer-encoding; bh=pFXyiSy5mSijsi+vyJp9AB0dIFK/hLMP5evPgimL4oI=; b=nT//ASu3kjB1yTgZVaPmiOOsJv/sdzgDl247t8dcGM0kHoePlSQ8SAPszJGV9J9iwg 3G5vFa5H7CmK9wz87ZXOgKP+vMKwGBanH517h8eyTtpkrGSeOo5krQYZt4n3FZ87OB9N SwXyQ4pRQMNIppPyKfsGqsKPsS9fDxyg1UWFf0XoToUTYMlGYWkGqCIemk8tXTGTtH5m fv/3BzJuf7jYr1Oxb47jEgZxCn7WZ6pqIovl2Tdk67i5w0Z6UwyFQPU3XPGPrhr/zcS4 Uv1N2WZTW1fvnBEphMbAQbCGTRiy0kBOYNgq4R6eWs8X+8nejdluBa73mgV7JbwZbN30 I2lw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:from:to:date:message-id:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=pFXyiSy5mSijsi+vyJp9AB0dIFK/hLMP5evPgimL4oI=; b=Wjr2HLMEoSqoA4VPThcw3wm558LVMh5YDEAi7QminD80LKwEWwlDqeJlicGDesPZpA le2q+bkEOHruDG9r/+64jEipojhRvQvga+AxVRYbb7+V6uXaoSkpuE9dURmJp3WZM4HV 2/x84cILRdrOcrKCAfbE1OvHL3okVPgoiUtek/rgE+rGYbiZODldPtQUAud4G7VwIw4+ p/9kWaIoVFmMQGz8g5BYrxicbcDxD510uZNxyZpmI+nwQGZbZFsV0G1UKmFxUkYHU5YN rAezeMBfuRQ0hKgq9EqmNShbhflflwlyF/EoZV3dXnoVqnrlOuzHdGXFFRvaasG7szc/ JVnQ== X-Gm-Message-State: AOAM532u6ifqJSGq73j9GkcAO8OI5raBtCDKPX7DZfVLhDQMXPwdDzNu Cx5WMhSesdVUpeyUyTwRCCw4aTH1ixKX X-Google-Smtp-Source: ABdhPJwxHpFS9FikZ0JUIYc0mk4r4o/AVbyPloTv5KlWztD4/Z4Jcgb2HFB09rgl94uVExhd3nfILQ== X-Received: by 2002:ac8:7285:: with SMTP id v5mr801915qto.300.1631724603382; Wed, 15 Sep 2021 09:50:03 -0700 (PDT) Received: from localhost (pool-96-237-52-188.bstnma.fios.verizon.net. [96.237.52.188]) by smtp.gmail.com with ESMTPSA id t3sm377604qkg.2.2021.09.15.09.50.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Sep 2021 09:50:02 -0700 (PDT) Subject: [PATCH v4 7/8] selinux: add support for the io_uring access controls From: Paul Moore To: linux-security-module@vger.kernel.org, selinux@vger.kernel.org, linux-audit@redhat.com, io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jens Axboe , Pavel Begunkov , Kumar Kartikeya Dwivedi Date: Wed, 15 Sep 2021 12:50:02 -0400 Message-ID: <163172460230.88001.3182498346819815467.stgit@olly> In-Reply-To: <163172413301.88001.16054830862146685573.stgit@olly> References: <163172413301.88001.16054830862146685573.stgit@olly> User-Agent: StGit/1.1 MIME-Version: 1.0 Precedence: bulk List-ID: This patch implements two new io_uring access controls, specifically support for controlling the io_uring "personalities" and IORING_SETUP_SQPOLL. Controlling the sharing of io_urings themselves is handled via the normal file/inode labeling and sharing mechanisms. The io_uring { override_creds } permission restricts which domains the subject domain can use to override it's own credentials. Granting a domain the io_uring { override_creds } permission allows it to impersonate another domain in io_uring operations. The io_uring { sqpoll } permission restricts which domains can create asynchronous io_uring polling threads. This is important from a security perspective as operations queued by this asynchronous thread inherit the credentials of the thread creator by default; if an io_uring is shared across process/domain boundaries this could result in one domain impersonating another. Controlling the creation of sqpoll threads, and the sharing of io_urings across processes, allow policy authors to restrict the ability of one domain to impersonate another via io_uring. As a quick summary, this patch adds a new object class with two permissions: io_uring { override_creds sqpoll } These permissions can be seen in the two simple policy statements below: allow domA_t domB_t : io_uring { override_creds }; allow domA_t self : io_uring { sqpoll }; Signed-off-by: Paul Moore --- v4: - no change v3: - removed work-in-progress warning from the description v2: - made the selinux_uring_* funcs static - removed the debugging code v1: - initial draft --- security/selinux/hooks.c | 34 ++++++++++++++++++++++++++++++++++ security/selinux/include/classmap.h | 2 ++ 2 files changed, 36 insertions(+) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 6517f221d52c..012e8504ed9e 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -7111,6 +7111,35 @@ static int selinux_perf_event_write(struct perf_event *event) } #endif +#ifdef CONFIG_IO_URING +/** + * selinux_uring_override_creds - check the requested cred override + * @new: the target creds + * + * Check to see if the current task is allowed to override it's credentials + * to service an io_uring operation. + */ +static int selinux_uring_override_creds(const struct cred *new) +{ + return avc_has_perm(&selinux_state, current_sid(), cred_sid(new), + SECCLASS_IO_URING, IO_URING__OVERRIDE_CREDS, NULL); +} + +/** + * selinux_uring_sqpoll - check if a io_uring polling thread can be created + * + * Check to see if the current task is allowed to create a new io_uring + * kernel polling thread. + */ +static int selinux_uring_sqpoll(void) +{ + int sid = current_sid(); + + return avc_has_perm(&selinux_state, sid, sid, + SECCLASS_IO_URING, IO_URING__SQPOLL, NULL); +} +#endif /* CONFIG_IO_URING */ + /* * IMPORTANT NOTE: When adding new hooks, please be careful to keep this order: * 1. any hooks that don't belong to (2.) or (3.) below, @@ -7349,6 +7378,11 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(perf_event_write, selinux_perf_event_write), #endif +#ifdef CONFIG_IO_URING + LSM_HOOK_INIT(uring_override_creds, selinux_uring_override_creds), + LSM_HOOK_INIT(uring_sqpoll, selinux_uring_sqpoll), +#endif + LSM_HOOK_INIT(locked_down, selinux_lockdown), /* diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h index 084757ff4390..698ccfdaf82d 100644 --- a/security/selinux/include/classmap.h +++ b/security/selinux/include/classmap.h @@ -254,6 +254,8 @@ struct security_class_mapping secclass_map[] = { { "integrity", "confidentiality", NULL } }, { "anon_inode", { COMMON_FILE_PERMS, NULL } }, + { "io_uring", + { "override_creds", "sqpoll", NULL } }, { NULL } }; From patchwork Wed Sep 15 16:50:08 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Moore X-Patchwork-Id: 12496875 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1BC9EC433EF for ; Wed, 15 Sep 2021 16:50:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 04DE66121F for ; Wed, 15 Sep 2021 16:50:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230470AbhIOQvc (ORCPT ); Wed, 15 Sep 2021 12:51:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36680 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230443AbhIOQva (ORCPT ); Wed, 15 Sep 2021 12:51:30 -0400 Received: from mail-qv1-xf35.google.com (mail-qv1-xf35.google.com [IPv6:2607:f8b0:4864:20::f35]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 121F1C061767 for ; Wed, 15 Sep 2021 09:50:11 -0700 (PDT) Received: by mail-qv1-xf35.google.com with SMTP id w8so2323246qvt.0 for ; Wed, 15 Sep 2021 09:50:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=paul-moore-com.20150623.gappssmtp.com; s=20150623; h=subject:from:to:date:message-id:in-reply-to:references:user-agent :mime-version:content-transfer-encoding; bh=znV6h22uLT4tju8GfDCyoAJth/iE5nhq2gX552Nh+J8=; b=yR4M9FMq5YkZZZnLVBGoHE8n/L7LBcuRYu45AIK6rpu6q86Bt8q97V42UpmZakk9Hk qy1Abyuha691Im0rYc9EK/tOxPEZ+1p++dVyuU49SBOnF3DsCPgp/ECkkaOcSk9hOYg9 uZwNWDENAneb/b3kwwfPpFtKTclqgTySmd7avIWwSBqFJauyZ+YBc6bH4I/Gmz4clP5w UOG2/ZoGWt1ti8+ruNUFKiGZJPPEEa2XjAF0DA2xVI/cJ3BaH4r06uP8JDKIZQ63Cap9 ayT/rIEu7My8B35KdwQFfy0AsExXY/vMA5Y0BemiwrEF4O/6W75CvXEWvQeBY3Bhk5kO rFyQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:from:to:date:message-id:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=znV6h22uLT4tju8GfDCyoAJth/iE5nhq2gX552Nh+J8=; b=kikBUKJw82YVlqOf22Ci/h61IAAkOwmCDcOMbAGMVQGR7tQgvdjxa0fYK1ZU9SFQ1f PpsERstgdN01WCeaDJgx9A+sG9wgCc9Z3Cv57s69aMpeN63yInMr+C+jiZz7HyF0fkKv XsUifYcGb3m8luoW8Z1HURYXj/f2gziiuGI0AyNUx+EtxCEZkMbY36aiDy8xERHqh2u9 Or5UbP5BmPfUv2ilZLO7NSEqhLOTUspYUE626rAgrkz7prUhtPwQeIWKm0T16d8FTu5/ q1ALzMin5/s3D/QAHPxaQWDnBA6bonngjkAHhSXeNk6OP2IHotg8SfofECcsEHy5k8Sf GxiA== X-Gm-Message-State: AOAM531jKr0Wp0mafZl4UHJEX7WbQFi/MqMwbwET+IhYJRWMUtKpsZ4u oNK8Jp0+655+yMHovQD8TJztCteoQgEv X-Google-Smtp-Source: ABdhPJx75T0dQPzt4WSic6uHD74Uop3/gZqSo+/ev3KVEiS5rzNOA3M5qoWYDRrYR2z4q+uilRE4LA== X-Received: by 2002:a05:6214:1394:: with SMTP id g20mr812980qvz.21.1631724609746; Wed, 15 Sep 2021 09:50:09 -0700 (PDT) Received: from localhost (pool-96-237-52-188.bstnma.fios.verizon.net. [96.237.52.188]) by smtp.gmail.com with ESMTPSA id w20sm377308qkj.116.2021.09.15.09.50.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Sep 2021 09:50:09 -0700 (PDT) Subject: [PATCH v4 8/8] Smack: Brutalist io_uring support From: Paul Moore To: linux-security-module@vger.kernel.org, selinux@vger.kernel.org, linux-audit@redhat.com, io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jens Axboe , Pavel Begunkov , Kumar Kartikeya Dwivedi Date: Wed, 15 Sep 2021 12:50:08 -0400 Message-ID: <163172460848.88001.15344229885190060624.stgit@olly> In-Reply-To: <163172413301.88001.16054830862146685573.stgit@olly> References: <163172413301.88001.16054830862146685573.stgit@olly> User-Agent: StGit/1.1 MIME-Version: 1.0 Precedence: bulk List-ID: From: Casey Schaufler Add Smack privilege checks for io_uring. Use CAP_MAC_OVERRIDE for the override_creds case and CAP_MAC_ADMIN for creating a polling thread. These choices are based on conjecture regarding the intent of the surrounding code. Signed-off-by: Casey Schaufler [PM: make the smack_uring_* funcs static, remove debug code] Signed-off-by: Paul Moore --- v4: - updated subject line v3: - removed debug code v2: - made the smack_uring_* funcs static v1: - initial draft --- security/smack/smack_lsm.c | 46 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index cacbe7518519..f90ab1efeb6d 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -4691,6 +4691,48 @@ static int smack_dentry_create_files_as(struct dentry *dentry, int mode, return 0; } +#ifdef CONFIG_IO_URING +/** + * smack_uring_override_creds - Is io_uring cred override allowed? + * @new: the target creds + * + * Check to see if the current task is allowed to override it's credentials + * to service an io_uring operation. + */ +static int smack_uring_override_creds(const struct cred *new) +{ + struct task_smack *tsp = smack_cred(current_cred()); + struct task_smack *nsp = smack_cred(new); + + /* + * Allow the degenerate case where the new Smack value is + * the same as the current Smack value. + */ + if (tsp->smk_task == nsp->smk_task) + return 0; + + if (smack_privileged_cred(CAP_MAC_OVERRIDE, current_cred())) + return 0; + + return -EPERM; +} + +/** + * smack_uring_sqpoll - check if a io_uring polling thread can be created + * + * Check to see if the current task is allowed to create a new io_uring + * kernel polling thread. + */ +static int smack_uring_sqpoll(void) +{ + if (smack_privileged_cred(CAP_MAC_ADMIN, current_cred())) + return 0; + + return -EPERM; +} + +#endif /* CONFIG_IO_URING */ + struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = { .lbs_cred = sizeof(struct task_smack), .lbs_file = sizeof(struct smack_known *), @@ -4843,6 +4885,10 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(inode_copy_up, smack_inode_copy_up), LSM_HOOK_INIT(inode_copy_up_xattr, smack_inode_copy_up_xattr), LSM_HOOK_INIT(dentry_create_files_as, smack_dentry_create_files_as), +#ifdef CONFIG_IO_URING + LSM_HOOK_INIT(uring_override_creds, smack_uring_override_creds), + LSM_HOOK_INIT(uring_sqpoll, smack_uring_sqpoll), +#endif };