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 A3B478F75 for ; Sun, 16 Jul 2023 20:18:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 25692C433C9; Sun, 16 Jul 2023 20:18:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689538688; bh=FKwkdh2mokyMTOLw2JfdnLXiIOww9tEyAmodkPwuKrA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=trsOu/cdJTLFsUKp/Lnow/r6d9CSApxNcFEbWC64XzHL35Ld+ekHndhy1xNOmM4rN upJBuA0G9+N/JYfDy7PeHhJ+ND/pVuUWmWo1h9dN6KFvLV/UByY3J8ULuJ16Z3hcIx /H7N17nTF9btbG+RpP2Df3Tpm39wu5HQYao2+mLM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Paulo Alcantara (SUSE)" , Shyam Prasad N , Steve French , Sasha Levin Subject: [PATCH 6.4 541/800] cifs: prevent use-after-free by freeing the cfile later Date: Sun, 16 Jul 2023 21:46:34 +0200 Message-ID: <20230716195001.658058775@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230716194949.099592437@linuxfoundation.org> References: <20230716194949.099592437@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Shyam Prasad N [ Upstream commit 33f736187d08f6bc822117629f263b97d3df4165 ] In smb2_compound_op we have a possible use-after-free which can cause hard to debug problems later on. This was revealed during stress testing with KASAN enabled kernel. Fixing it by moving the cfile free call to a few lines below, after the usage. Fixes: 76894f3e2f71 ("cifs: improve symlink handling for smb2+") Reviewed-by: Paulo Alcantara (SUSE) Signed-off-by: Shyam Prasad N Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/smb/client/smb2inode.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/smb/client/smb2inode.c b/fs/smb/client/smb2inode.c index 163a03298430d..7e3ac4cb4efa6 100644 --- a/fs/smb/client/smb2inode.c +++ b/fs/smb/client/smb2inode.c @@ -398,9 +398,6 @@ static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon, rsp_iov); finished: - if (cfile) - cifsFileInfo_put(cfile); - SMB2_open_free(&rqst[0]); if (rc == -EREMCHG) { pr_warn_once("server share %s deleted\n", tcon->tree_name); @@ -529,6 +526,9 @@ static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon, break; } + if (cfile) + cifsFileInfo_put(cfile); + if (rc && err_iov && err_buftype) { memcpy(err_iov, rsp_iov, 3 * sizeof(*err_iov)); memcpy(err_buftype, resp_buftype, 3 * sizeof(*err_buftype)); -- 2.39.2