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 102E61D5AD7; Wed, 6 Nov 2024 12:10:03 +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=1730895004; cv=none; b=rsDiXjrNm/vWYzzTBH9IHKkhy73AAHrfnjtOvc8aOh9GaQ+pKVK3d7KUm/eZ7NarK62wNyb8fFntD19EtIwQ/dDiGQVqGGx+1+ikLZISRH4mGhQlwNxvXfUqoTrUbD/v6VqspjmLVRh/Jv3uHZ1bL0K+rVYWokPzuHhoR51vMTM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730895004; c=relaxed/simple; bh=kKaBlDNOL9KaYaIFD5igVamhepso3nOpXfhPBlGCDDg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=K5PsH+OAEHddvwpBCFa4Dwl0m+G5mWWSUoMv4FOwneWqzDT0QYmb2mGPyh7piqXqsVvH/Fz1KJHyO3oRf8+myEhHfr5NvIy9tCd/VGVKvQF4AdJtvIxYIaUZFGqvAEPzBYgdCJmlV7e49MZjhJuraLxsWpGlLbP+aw6T7caaZIA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2khePoRT; 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="2khePoRT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E70AC4CECD; Wed, 6 Nov 2024 12:10:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1730895003; bh=kKaBlDNOL9KaYaIFD5igVamhepso3nOpXfhPBlGCDDg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2khePoRTb0LivHV4OlsssE3cbAJSrEOukEFJFwmtkeH+1e2mpegegl8qcTcaeEiNX o6YxOf53SdVaLvk8hnjmlPbGWjCiFQDKCyBIT6l7QwBvHe9uN+bseMid0lnusUkYm/ UitbERUhnBKntM7kmg5NG2haZ5JMgvm54CSaDu5A= 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 4.19 072/350] smackfs: Use rcu_assign_pointer() to ensure safe assignment in smk_set_cipso Date: Wed, 6 Nov 2024 13:00:00 +0100 Message-ID: <20241106120322.675878702@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241106120320.865793091@linuxfoundation.org> References: <20241106120320.865793091@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 4.19-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 61e734baa332a..83dbfa26a6518 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -948,7 +948,7 @@ 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