From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793817239; b=H6gSHmRrMiyOSqVbs3vgYaW4J0DIw58/IzrhVmwG//QhyAuLK2+Da/ZUOZQXK/8X0/0B G0puN3A4Y7yYM6KAFnvQt+YrGnqdZ0F9u4/5FWSul6sZClcMc+zbdIe51tf4jnMVwtBRz 72s3uREca2Vde/y1erw0VTMznYr6IpkuCFYDwq7rm/7ImmxKhl09yZU+iJEMOP+0Qz7lD KLhAW25vdKleeiLDIyuCOS2H04hI9AKvOaXbMqw/NO6CVgqK6i1x175DCm1glWPy7bdky 7o6RYdI5BjjTm1el8IVHfil55tji8n/ucz9jnIyXFvU7jswBHZeNE1FIlYI7bzvjY7w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793817239; h=Received:DKIM-Signature:Subject:To:Cc:From:Date:Message-ID: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=jhzmn3+iWiZEm6lodzCMn5g48S7/asW6vMtfRqjd3Pc=; b=BOIKiI+hn7z2xyCgqCO09yedKcO3dbQ0q0hOW2lbblMlL0/AnP6MoX4xqVLY+m5nGBRG Le9MJ9sYr8+efXQEsbzTpEyVL+NELuDnkptnJOASFoRkTDk9GVYkFaMomzT7auzEfZ5v0 kM0QN83u0uyOOwvMuSVIzwP7I5XT9gQldbzFh/+5OrWqRDwT9Ue6/v2eEyi+zqtxrF4T0 ciTNT5vBITkXSdSG3crENKwQyZLfXcapTZCVm/fjgne4rKCSuwNTO5uu0rds0DE7SUitT 7ATYYpLeEfvki4FLO/Igx55GMWTh1HpTiKbCy8JiFllCdqqHqfTJIuYq0xrsq4USanA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=qtBnFq4L; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 365BC606A326 for ; Wed, 4 Nov 2026 18:33:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=qtBnFq4L Received: by smtp.kernel.org (Postfix) with ESMTPSA id C0E311F000C1; Wed, 4 Nov 2026 18:33:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793817239; bh=jhzmn3+iWiZEm6lodzCMn5g48S7/asW6vMtfRqjd3Pc=; h=Subject:To:Cc:From:Date; b=qtBnFq4LY9qKwb+XGDeNj6wVr3qS10V3tBQVpwIUWD3ZR8DWZm14xzskBZ/IITqym c0dbPRoOaMn06lHWUQj7j591wr5sI57oTwJfGEDBBLeuzpgsjkMLTI9fh3t/Swg7VH zC8S4zr7638IwieOyUBCsvopF3BbVVnqE2NUC+WY= Subject: FAILED: patch "[PATCH] smb: client: reject FIND data areas that run past the" failed to apply to 6.12-stable tree To: diego@bynar.io,dhowells@redhat.com,pc@manguebit.org Cc: From: Date: Wed, 04 Nov 2026 13:33:56 -0500 Message-ID: <2026110456-awry-fastness-1fdf@gregkh> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x 29bd6773187cb5c1bbbdf90d677c6add7d58af26 # git commit -s git send-email --to '' --in-reply-to '2026110456-awry-fastness-1fdf@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 29bd6773187cb5c1bbbdf90d677c6add7d58af26 Mon Sep 17 00:00:00 2001 From: Diego Oliva Date: Tue, 29 Sep 2026 10:16:34 +0100 Subject: [PATCH] smb: client: reject FIND data areas that run past the received response CIFSFindFirst() and CIFSFindNext() take the directory entries of a TRANS2_FIND_FIRST2 or TRANS2_FIND_NEXT2 response from DataOffset for DataCount bytes. validate_t2() bounds DataOffset at 1024 and ParameterCount + DataCount by the byte count, and nothing compares DataOffset + DataCount with the number of bytes SendReceive() copied into the buffer. smb_init() places the request and the response in the same cifs_request allocation and cifs_buf_get() clears only the start of it, so a short response whose data area extends past its end has srch_entries_start point at bytes of the request that was just sent, or at whatever the allocation held before, and those bytes are parsed as directory entries. cifs_readdir() and find_cifs_entry() walk the entries with nxt_dir_entry(), which checks every entry but the first of a response against the end of the SMB; cifs_query_path_info() and cifs_backup_query_path_info() read the first entry with no check at all. Those reads stay inside the allocation, but what they return is not part of the response. The last entry, which LastNameOffset locates relative to the data area, is bounded against the received response by an earlier patch of this series, as is every entry that cifs_fill_dirent() parses; the walk itself and the two query functions are not. SMB1 is not negotiated by default; reaching this code requires an explicit vers=1.0 mount. Reject a response whose data area extends past the received length, with the -EINVAL that validate_t2() returns for the other malformed transaction responses. cifs_query_path_info() and cifs_backup_query_path_info() still read a whole entry from a data area that may be smaller than one; that is not changed here. A conforming server is not affected. The data block of a transaction response is part of the SMB, so DataOffset + DataCount cannot exceed the smbCalcSize() bytes that SendReceive() copies; coalesce_t2() appends each secondary response to the data area and adds its length to both DataCount and the byte count, which keeps that relation. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Assisted-by: Bynario AI Signed-off-by: Diego Oliva Reviewed-by: David Howells Signed-off-by: Paulo Alcantara diff --git a/fs/smb/client/cifssmb.c b/fs/smb/client/cifssmb.c index d8b1740b50fa..bb71fed940a5 100644 --- a/fs/smb/client/cifssmb.c +++ b/fs/smb/client/cifssmb.c @@ -4410,8 +4410,9 @@ CIFSFindFirst(const unsigned int xid, struct cifs_tcon *tcon, /* level 257 SMB_ */ TRANSACTION2_FFIRST_REQ *pSMB = NULL; TRANSACTION2_FFIRST_RSP *pSMBr = NULL; - T2_FFIRST_RSP_PARMS *parms; + unsigned int data_off, data_count; struct nls_table *nls_codepage; + T2_FFIRST_RSP_PARMS *parms; unsigned int in_len, lnoff; __u16 params, byte_count; int bytes_returned = 0; @@ -4530,11 +4531,19 @@ CIFSFindFirst(const unsigned int xid, struct cifs_tcon *tcon, return rc; } + data_off = le16_to_cpu(pSMBr->t2.DataOffset); + data_count = le16_to_cpu(pSMBr->t2.DataCount); + if (data_off + data_count > (unsigned int)bytes_returned) { + cifs_dbg(VFS, "%s: data area offset %u count %u past response length %d\n", + __func__, data_off, data_count, bytes_returned); + cifs_buf_release(pSMB); + return -EINVAL; + } + psrch_inf->unicode = !!(pSMBr->hdr.Flags2 & SMBFLG2_UNICODE); psrch_inf->ntwrk_buf_start = (char *)pSMBr; psrch_inf->smallBuf = false; - psrch_inf->srch_entries_start = (char *)&pSMBr->hdr.Protocol + - le16_to_cpu(pSMBr->t2.DataOffset); + psrch_inf->srch_entries_start = (char *)&pSMBr->hdr.Protocol + data_off; parms = (T2_FFIRST_RSP_PARMS *)((char *)&pSMBr->hdr.Protocol + le16_to_cpu(pSMBr->t2.ParameterOffset)); @@ -4567,8 +4576,9 @@ int CIFSFindNext(const unsigned int xid, struct cifs_tcon *tcon, { TRANSACTION2_FNEXT_REQ *pSMB = NULL; TRANSACTION2_FNEXT_RSP *pSMBr = NULL; - T2_FNEXT_RSP_PARMS *parms; + unsigned int data_off, data_count; unsigned int name_len, in_len; + T2_FNEXT_RSP_PARMS *parms; unsigned int lnoff; __u16 params, byte_count; char *response_data; @@ -4652,13 +4662,22 @@ int CIFSFindNext(const unsigned int xid, struct cifs_tcon *tcon, cifs_buf_release(pSMB); return rc; } + + data_off = le16_to_cpu(pSMBr->t2.DataOffset); + data_count = le16_to_cpu(pSMBr->t2.DataCount); + if (data_off + data_count > (unsigned int)bytes_returned) { + cifs_dbg(VFS, "%s: data area offset %u count %u past response length %d\n", + __func__, data_off, data_count, bytes_returned); + cifs_buf_release(pSMB); + return -EINVAL; + } + /* BB fixme add lock for file (srch_info) struct here */ psrch_inf->unicode = !!(pSMBr->hdr.Flags2 & SMBFLG2_UNICODE); response_data = (char *)&pSMBr->hdr.Protocol + le16_to_cpu(pSMBr->t2.ParameterOffset); parms = (T2_FNEXT_RSP_PARMS *)response_data; - response_data = (char *)&pSMBr->hdr.Protocol + - le16_to_cpu(pSMBr->t2.DataOffset); + response_data = (char *)&pSMBr->hdr.Protocol + data_off; if (psrch_inf->smallBuf) cifs_small_buf_release(psrch_inf->ntwrk_buf_start);