From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 19EE61EABC3; Tue, 15 Oct 2024 11:45:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728992744; cv=none; b=L4dYgFcqklbI9tNPeiwm6VsOKRBDREt2WBctV5C++3cTfX1p0ew6eFl/Q3VI/oWF/k/F0JlK1iADUY4v8/Stnz07y0o22ErEm34e9q6MYREJBd6BBbx/a4skPSSAMphdu114SWCxAvfQhcrmyzle7jaxZUh6xH9tQ+B9z6y7bGY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728992744; c=relaxed/simple; bh=Vm7mqtZ5lMCfDsFDdZoRkelZMpcjd0daPBOII1h0Ueg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fSpHbJlK4R0uuSOUr/zzxBEMyviboeqs1sG9MERaFvStSOxbilu7JEG49o8/mtG5aQrhF9lt1PlyV/5AbODCObCn1BJNX1vl6uTXn+zbekVITG1jItm1UYE/WyuhIc9ns/6vzM0BBm8luXWunaSNakE8LaxH+LfbSESz/6D1wDM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PEWcWPkD; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="PEWcWPkD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75F8FC4CEC6; Tue, 15 Oct 2024 11:45:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1728992743; bh=Vm7mqtZ5lMCfDsFDdZoRkelZMpcjd0daPBOII1h0Ueg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PEWcWPkDC35aYzfxpMgxw7nTk9N4l1aNJoZYC4np0EjaqczUxUhqJ3W3IRhuEs7rq GcqbBgQQtF7vFjYsPPDxXy3An/bF9phQ/1yczM+FIvKFxC3eDiC1QqKIMxMdb2eWDv XccFhpGtvjI5ZQ+AOegz6rDm7JwQAS3xAmggqNOs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiawei Ye , Casey Schaufler , Sasha Levin Subject: [PATCH 5.15 204/691] smackfs: Use rcu_assign_pointer() to ensure safe assignment in smk_set_cipso Date: Tue, 15 Oct 2024 13:22:32 +0200 Message-ID: <20241015112448.456305697@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241015112440.309539031@linuxfoundation.org> References: <20241015112440.309539031@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiawei Ye [ Upstream commit 2749749afa071f8a0e405605de9da615e771a7ce ] In the `smk_set_cipso` function, the `skp->smk_netlabel.attr.mls.cat` field is directly assigned to a new value without using the appropriate RCU pointer assignment functions. According to RCU usage rules, this is illegal and can lead to unpredictable behavior, including data inconsistencies and impossible-to-diagnose memory corruption issues. This possible bug was identified using a static analysis tool developed by myself, specifically designed to detect RCU-related issues. To address this, the assignment is now done using rcu_assign_pointer(), which ensures that the pointer assignment is done safely, with the necessary memory barriers and synchronization. This change prevents potential RCU dereference issues by ensuring that the `cat` field is safely updated while still adhering to RCU's requirements. Fixes: 0817534ff9ea ("smackfs: Fix use-after-free in netlbl_catmap_walk()") Signed-off-by: Jiawei Ye Signed-off-by: Casey Schaufler Signed-off-by: Sasha Levin --- security/smack/smackfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c index 27fd7744e0fc0..f6961a8895296 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -920,7 +920,7 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf, rc = smk_netlbl_mls(maplevel, mapcatset, &ncats, SMK_CIPSOLEN); if (rc >= 0) { old_cat = skp->smk_netlabel.attr.mls.cat; - skp->smk_netlabel.attr.mls.cat = ncats.attr.mls.cat; + rcu_assign_pointer(skp->smk_netlabel.attr.mls.cat, ncats.attr.mls.cat); skp->smk_netlabel.attr.mls.lvl = ncats.attr.mls.lvl; synchronize_rcu(); netlbl_catmap_free(old_cat); -- 2.43.0