From patchwork Fri May 21 21:50:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Moore X-Patchwork-Id: 12273835 X-Patchwork-Delegate: paul@paul-moore.com 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=ham 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 94B5DC04FF3 for ; Fri, 21 May 2021 21:50:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7943D613EA for ; Fri, 21 May 2021 21:50:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229921AbhEUVwD (ORCPT ); Fri, 21 May 2021 17:52:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57122 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229915AbhEUVwD (ORCPT ); Fri, 21 May 2021 17:52:03 -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 90A3EC0613CE for ; Fri, 21 May 2021 14:50:39 -0700 (PDT) Received: by mail-qk1-x72d.google.com with SMTP id v8so21349761qkv.1 for ; Fri, 21 May 2021 14:50:39 -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=yVODgsBH3pwJySxgTtmB98vfatsbGIZ28oW0IWdkpT0=; b=y0fBY74DDWd7J2Q4LAZ8Tc+S4IeIm0ggxMFDvuLxRMwxE4pBi5YQBOJb0yVHgNCjw/ 6nXTDhdi237ivx9OpFxTaSt/2w0iOl5KaPuinDGmWlVHyOd7eh+AjdQCE6TfppiXA1qw LiqA51F2Iji/7K4YBZqYJ6Jp3NMKsLAP/zlozfNFomva6gAUX0B3D0Rj7BviOlZga5fz qRdiUDzGr928A7t5cuzs8jxkLCfqqLd8UOFcH0J8HKrsYx4tgSDOcPII0hN8iO4TXTrm Vdoi2lzlO1NwBXvypm8t69RMAW+j40GzHN4PFkD789xwDPx0IIrJSlbaKk8KCBY7Iodj VKKQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:date:message-id:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=yVODgsBH3pwJySxgTtmB98vfatsbGIZ28oW0IWdkpT0=; b=HjZ2utoOotbX1C8MmXz4JCG6k4Hx6gN0Poo9aIgTk5nk7C4t7zVgwk+uC0llbQbdiG B4R8DB4X0bcBXXobS4D91/869lIlCkjx0Q9rR6xleHCzdBCqE008RCyb36syv50vfjBE 8MKZTzxIN8upYBzTLJ++1bEJ6K1KNJHgujhO1ThSrKamIs6v1LmPzaeHgHS7+nyz09kT UiWOvuTv9uVjWLwnZt1cWPFaxLcXaMF4ldjeX5Rb2/kwq5JjEsXgXIcbvrzQu8i4IEPQ AESn4UFg+dTWQnNUu/salzSjNMDgTUJ8xlcLk5AFPmjh4d460kKk88IgFKf4uOJBR3KH DPrw== X-Gm-Message-State: AOAM533yOn7S3aD4+fCQTD1vQnxOmKc4nThu35DYbrZ3PA62eJWnLJXv OGmE8J5Ov6lv6jRFcGASUCsN X-Google-Smtp-Source: ABdhPJy8CbcdNgRZ+79GQ7zlutlj5Jo5vuvLZxS0af1cMkIKs15miDkHS/LPNWRaK6XS5ozPHjj0Fg== X-Received: by 2002:a37:ac0d:: with SMTP id e13mr11837998qkm.426.1621633838636; Fri, 21 May 2021 14:50:38 -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 h8sm4914383qtp.46.2021.05.21.14.50.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 May 2021 14:50:38 -0700 (PDT) Subject: [RFC PATCH 9/9] Smack: Brutalist io_uring support with debug 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, Kumar Kartikeya Dwivedi , Jens Axboe , Alexander Viro Date: Fri, 21 May 2021 17:50:37 -0400 Message-ID: <162163383761.8379.7421085717625472402.stgit@sifl> In-Reply-To: <162163367115.8379.8459012634106035341.stgit@sifl> References: <162163367115.8379.8459012634106035341.stgit@sifl> User-Agent: StGit/1.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org 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 Signed-off-by: Paul Moore --- security/smack/smack_lsm.c | 64 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 223a6da0e6dc..f6423c0096e9 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -4691,6 +4691,66 @@ 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. + */ +int smack_uring_override_creds(const struct cred *new) +{ + struct task_smack *tsp = smack_cred(current_cred()); + struct task_smack *nsp = smack_cred(new); + +#if 1 + if (tsp->smk_task == nsp->smk_task) + pr_info("%s: Smack matches %s\n", __func__, + tsp->smk_task->smk_known); + else + pr_info("%s: Smack override check %s to %s\n", __func__, + tsp->smk_task->smk_known, nsp->smk_task->smk_known); +#endif + /* + * 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 1 + pr_info("%s: Smack sqpoll %s\n", __func__, + smack_privileged_cred(CAP_MAC_OVERRIDE, current_cred()) ? + "ok by Smack" : "disallowed (No CAP_MAC_OVERRIDE)"); +#endif + 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. + */ +int smack_uring_sqpoll(void) +{ +#if 1 + pr_info("%s: Smack new ring %s\n", __func__, + smack_privileged_cred(CAP_MAC_ADMIN, current_cred()) ? + "ok by Smack" : "disallowed (No CAP_MAC_ADMIN)"); +#endif + 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 +4903,10 @@ 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 };