From patchwork Sat Sep 28 21:59:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Pali_Roh=C3=A1r?= X-Patchwork-Id: 13814759 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 0B1D1187347; Sat, 28 Sep 2024 22:00:47 +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=1727560848; cv=none; b=BQ5v49ceOM8iTwRmwCvnG4pF7TO8d0Y0bQ0Jvkqyb0TWtAjwZvJzO16yKzDRPkMfyV/xOkSceEK4eTEu7S+7gsd5QeweLsROF2vX46W1UV4/5vT3TQ6QGVt1P1H1YQHgTtIyskirwrZ22upnoc55h2ui2VaGWOqSJIP7gf4sFO0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727560848; c=relaxed/simple; bh=Nqkkzjy+oFOwXzYUoBJUIL1MmPuVBHIvi/pv18rAyK0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=oMJc0mf9UsPY6vbT5EbqKW7PF+/zXUGfFeYoDXe90hjkVRss7t7ZOD1tohqYp5y8JSdwc/L02JcVMgadU6BnGcdGyPGsB+4rQ3muQHSvHzIwysvVLvcmPXl+T9geL41SdK3s5cBHdohTf0Pbf3+bHZhIyss3c7dEJg1Sh4vspH0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cksvZ6JC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cksvZ6JC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A32E8C4CED0; Sat, 28 Sep 2024 22:00:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727560847; bh=Nqkkzjy+oFOwXzYUoBJUIL1MmPuVBHIvi/pv18rAyK0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cksvZ6JCi5VSD4a7dMInohSiPPyy0WI4KbyeJWJ0sheXwEQCyuKjuV6WT2+4RwOy8 S4MoyMnT5rZ+0K7rt8y/nOvzAOXyPaYXHl3F2WUTVhhj+809lSNF9bI5WQ2fn+vCW6 z8p9cb5URZdiFSCclJBWL2qKO/em1Q8fk9xYYxz565pq/lB1RYHX88287tSUaE7SBu 5AZkYLtmDxCWmhMkNUol1kEINleTnObQpBlibQMij+knFlbPHALcPBDhPxIg2zHUnr KayKqvgXUUSxc6bHLvI3RXx/Px5FDZtg6cEITuUzBNcJQjwNilApDTYAA6X4+Oxolc 2n8TrShDFvn5w== Received: by pali.im (Postfix) id 9A42AC7D; Sun, 29 Sep 2024 00:00:41 +0200 (CEST) From: =?utf-8?q?Pali_Roh=C3=A1r?= To: Steve French , Paulo Alcantara , Ronnie Sahlberg Cc: linux-cifs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 7/8] cifs: Validate content of NFS reparse point buffer Date: Sat, 28 Sep 2024 23:59:47 +0200 Message-Id: <20240928215948.4494-8-pali@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20240928215948.4494-1-pali@kernel.org> References: <20240928215948.4494-1-pali@kernel.org> Precedence: bulk X-Mailing-List: linux-cifs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Symlink target location stored in DataBuffer is encoded in UTF-16. So check that symlink DataBuffer length is non-zero and even number. And check that DataBuffer does not contain UTF-16 null codepoint because Linux cannot process symlink with null byte. DataBuffer for char and block devices is 8 bytes long as it contains two 32-bit numbers (major and minor). Add check for this. DataBuffer buffer for sockets and fifos zero-length. Add checks for this. Signed-off-by: Pali Rohár --- fs/smb/client/reparse.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/fs/smb/client/reparse.c b/fs/smb/client/reparse.c index e3cf7ae516cb..35e8f2e18530 100644 --- a/fs/smb/client/reparse.c +++ b/fs/smb/client/reparse.c @@ -330,6 +330,18 @@ static int parse_reparse_posix(struct reparse_posix_data *buf, switch ((type = le64_to_cpu(buf->InodeType))) { case NFS_SPECFILE_LNK: + if (len == 0 || (len % 2)) { + cifs_dbg(VFS, "srv returned malformed nfs symlink buffer\n"); + return -EIO; + } + /* + * Check that buffer does not contain UTF-16 null codepoint + * because Linux cannot process symlink with null byte. + */ + if (UniStrnlen((wchar_t *)buf->DataBuffer, len/2) != len/2) { + cifs_dbg(VFS, "srv returned null byte in nfs symlink target location\n"); + return -EIO; + } data->symlink_target = cifs_strndup_from_utf16(buf->DataBuffer, len, true, cifs_sb->local_nls); @@ -340,8 +352,19 @@ static int parse_reparse_posix(struct reparse_posix_data *buf, break; case NFS_SPECFILE_CHR: case NFS_SPECFILE_BLK: + /* DataBuffer for block and char devices contains two 32-bit numbers */ + if (len != 8) { + cifs_dbg(VFS, "srv returned malformed nfs buffer for type: 0x%llx\n", type); + return -EIO; + } + break; case NFS_SPECFILE_FIFO: case NFS_SPECFILE_SOCK: + /* DataBuffer for fifos and sockets is empty */ + if (len != 0) { + cifs_dbg(VFS, "srv returned malformed nfs buffer for type: 0x%llx\n", type); + return -EIO; + } break; default: cifs_dbg(VFS, "%s: unhandled inode type: 0x%llx\n",