From patchwork Tue Dec 6 15:02:33 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Xu X-Patchwork-Id: 13066054 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E3F7C352A1 for ; Tue, 6 Dec 2022 15:07:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234673AbiLFPHj (ORCPT ); Tue, 6 Dec 2022 10:07:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60546 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234859AbiLFPGv (ORCPT ); Tue, 6 Dec 2022 10:06:51 -0500 Received: from mail-pj1-x102a.google.com (mail-pj1-x102a.google.com [IPv6:2607:f8b0:4864:20::102a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 135DB2F03F for ; Tue, 6 Dec 2022 07:03:11 -0800 (PST) Received: by mail-pj1-x102a.google.com with SMTP id fa4-20020a17090af0c400b002198d1328a0so1747871pjb.0 for ; Tue, 06 Dec 2022 07:03:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=RP30KXKl/PR6YPpKgU+DDNG5UwR2kZxBVDTlEl1cNxU=; b=HPjs8mheLAahBm8OUAn4PnD0Mw9299JNdm/Ya3WP81eG9XgGqqNUb1NxHROe4uAzpa pxH4GbCDjdsUHJZFXJDWpAGkq0hfWPstAQ4vbO8Nd7CmrtGPKaiK0LCfcK9X8GCoRloL pYH55QtHDsWGwxU98YexyagX1ikk0x6JAHEyM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=RP30KXKl/PR6YPpKgU+DDNG5UwR2kZxBVDTlEl1cNxU=; b=HJGtm4wAm5MI10elh+rxpFH3+L3Kf3XSJzjZd+urJLfxPvttrxMn5h84xsGnRriOq0 Yhp0Rac1Lish3yI63Tzn1v0A/0hIc+kCSmPtE32HkMg0S93wahIwZGTkWp7r8tmussqo FpuaRIYI3RbpqrU9AXBEiF4kQUOqOBSElagtPmhVB5zEMyPB82LbwcOReuDsoqWKgK6Y 9ga5Nzh2KkY+r8kMhwWCsidQZT9QrVok+i997rwogIuaRIMHCefKMLQtCcOdRe9kEJNP VVNNiX0x3rIxnrfsTkgJC8y2AdX+ftcbeso6bbleb9QxV2qE+S8hacavCFlnwRsp7JIk IdSw== X-Gm-Message-State: ANoB5pk6yBVDDLw4Y9kkU0Kp8jn1fM1HfqDZb3Y5I3nbTqgbQilrsVBQ XwYJFPlAvw1fUNmOvdy0Y81BjQ== X-Google-Smtp-Source: AA0mqf6IKN3LZHIUjL7BHnLwCPmED6KHQZ9tjiZ4ffklorTZcvYizCxxLPNGz7/31lHRh1As5QqOWA== X-Received: by 2002:a17:90a:13c4:b0:219:e3de:53e3 with SMTP id s4-20020a17090a13c400b00219e3de53e3mr7665466pjf.87.1670338978111; Tue, 06 Dec 2022 07:02:58 -0800 (PST) Received: from jeffxud.c.googlers.com.com (30.202.168.34.bc.googleusercontent.com. [34.168.202.30]) by smtp.gmail.com with ESMTPSA id 62-20020a621441000000b00575bab45644sm3343019pfu.61.2022.12.06.07.02.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Dec 2022 07:02:57 -0800 (PST) From: jeffxu@chromium.org To: skhan@linuxfoundation.org, keescook@chromium.org Cc: akpm@linux-foundation.org, dmitry.torokhov@gmail.com, dverkamp@chromium.org, hughd@google.com, jeffxu@google.com, jorgelo@chromium.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, jannh@google.com, linux-hardening@vger.kernel.org, Jeff Xu , kernel test robot Subject: [PATCH v4 6/6] mm/memfd: security hook for memfd_create Date: Tue, 6 Dec 2022 15:02:33 +0000 Message-Id: <20221206150233.1963717-7-jeffxu@google.com> X-Mailer: git-send-email 2.39.0.rc0.267.gcb52ba06e7-goog In-Reply-To: <20221206150233.1963717-1-jeffxu@google.com> References: <20221206150233.1963717-1-jeffxu@google.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org From: Jeff Xu The new security_memfd_create allows lsm to check flags of memfd_create. The security by default system (such as chromeos) can use this to implement system wide lsm to allow only non-executable memfd being created. Signed-off-by: Jeff Xu Reported-by: kernel test robot --- include/linux/lsm_hook_defs.h | 1 + include/linux/lsm_hooks.h | 4 ++++ include/linux/security.h | 6 ++++++ mm/memfd.c | 5 +++++ security/security.c | 13 +++++++++++++ 5 files changed, 29 insertions(+) diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index ec119da1d89b..fd40840927c8 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -164,6 +164,7 @@ LSM_HOOK(int, 0, file_alloc_security, struct file *file) LSM_HOOK(void, LSM_RET_VOID, file_free_security, struct file *file) LSM_HOOK(int, 0, file_ioctl, struct file *file, unsigned int cmd, unsigned long arg) +LSM_HOOK(int, 0, memfd_create, char *name, unsigned int flags) LSM_HOOK(int, 0, mmap_addr, unsigned long addr) LSM_HOOK(int, 0, mmap_file, struct file *file, unsigned long reqprot, unsigned long prot, unsigned long flags) diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 4ec80b96c22e..5a18a6552278 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -543,6 +543,10 @@ * simple integer value. When @arg represents a user space pointer, it * should never be used by the security module. * Return 0 if permission is granted. + * @memfd_create: + * @name is the name of memfd file. + * @flags is the flags used in memfd_create. + * Return 0 if permission is granted. * @mmap_addr : * Check permissions for a mmap operation at @addr. * @addr contains virtual address that will be used for the operation. diff --git a/include/linux/security.h b/include/linux/security.h index ca1b7109c0db..5b87a780822a 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -384,6 +384,7 @@ int security_file_permission(struct file *file, int mask); int security_file_alloc(struct file *file); void security_file_free(struct file *file); int security_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg); +int security_memfd_create(char *name, unsigned int flags); int security_mmap_file(struct file *file, unsigned long prot, unsigned long flags); int security_mmap_addr(unsigned long addr); @@ -963,6 +964,11 @@ static inline int security_file_ioctl(struct file *file, unsigned int cmd, return 0; } +static inline int security_memfd_create(char *name, unsigned int flags) +{ + return 0; +} + static inline int security_mmap_file(struct file *file, unsigned long prot, unsigned long flags) { diff --git a/mm/memfd.c b/mm/memfd.c index 92f0a5765f7c..f04ed5f0474f 100644 --- a/mm/memfd.c +++ b/mm/memfd.c @@ -356,6 +356,11 @@ SYSCALL_DEFINE2(memfd_create, goto err_name; } + /* security hook for memfd_create */ + error = security_memfd_create(name, flags); + if (error) + return error; + if (flags & MFD_HUGETLB) { file = hugetlb_file_setup(name, 0, VM_NORESERVE, HUGETLB_ANONHUGE_INODE, diff --git a/security/security.c b/security/security.c index 79d82cb6e469..5c018e080923 100644 --- a/security/security.c +++ b/security/security.c @@ -1010,6 +1010,19 @@ int security_sb_clone_mnt_opts(const struct super_block *oldsb, } EXPORT_SYMBOL(security_sb_clone_mnt_opts); +int security_add_mnt_opt(const char *option, const char *val, int len, + void **mnt_opts) +{ + return call_int_hook(sb_add_mnt_opt, -EINVAL, + option, val, len, mnt_opts); +} +EXPORT_SYMBOL(security_add_mnt_opt); + +int security_memfd_create(char *name, unsigned int flags) +{ + return call_int_hook(memfd_create, 0, name, flags); +} + int security_move_mount(const struct path *from_path, const struct path *to_path) { return call_int_hook(move_mount, 0, from_path, to_path);