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=1793817241; b=cS5GAjTXdls1ub+shzoAMH8ohjuLpNijoqh/hvhMcM9bsPeQ/GehCpMk96nmNDPJfCoO lByuYbvgiY+EyhaOeI1xg3CgmertKB46t3k/cllvxgTlhkSgzlKo485X6lqVeyv69ROI3 gauy2gcIe2ZFBx/l0cPE7xu0KVPJoAYnFjZPf70gLV1okI7k+d7dyRglPFV2sS0h1eUgs AGvAMMG/G/MjS7hLocgx/f91+5IMA91dCvXbT6TDADz001M2oZEfQ5nqWFl8U09Tr+nKt No2vfEbDsBuAVmQlil4TlJPssvehdydLJeSp3ihjKofXK2Cn7qjbJfWds6Sd4eaO/zQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793817241; h=Received:DKIM-Signature:Subject:To:Cc:From:Date:Message-ID: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=h/jVu1zd1v4b5xHYdVMgO0uA9PXzsFcMGdsnWjm3pg0=; b=yV/l+20x6e0UgmbdLfwO4o4mTmw22P+B76WHRFfW+2nwECcMSvEsaS1BRmThopO+yMnm QiXDEUaxfDlpeZA5LDLWV17BMZuwuyC5m/Et8tylfndhx71xXXnJjBgrrz9xV0+12dcJG xCP9FKj8C4D6V44kZA3Z9SuQJ4Mbw8yT2CITPF9qomnPMqcQJLLob3lHnlOlI3LAbYP1h aMCPwQJ07iR9aDoSOoIfGVaPJ+YeFuRRmK5vwZO45TCoVvfSldsnmK1Faq+ds3R30SqMh 4GyoPNE82qusRuVOwfFCFtEM31tK8p9tvswac1Y/H8ao4sfB4CiStOT//UFnzMNulVw== 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=sG0NWy8U; 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 D0F3D606A31B for ; Wed, 4 Nov 2026 18:34:00 +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=sG0NWy8U Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6EDEB1F000C1; Wed, 4 Nov 2026 18:34:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793817240; bh=h/jVu1zd1v4b5xHYdVMgO0uA9PXzsFcMGdsnWjm3pg0=; h=Subject:To:Cc:From:Date; b=sG0NWy8UlgIn15sleUAJrtZ9l+OHS0yougCP0mUgTbLPnanmu7dU/AGM/W/CJtiwM sdqjgQy/6IVy0wxQumruYhSOIjNtg7msz8Gc7zKXaMAb8LNIfR6JOnPu//He2DKZXI Q3O/GkMq80EJc54JzG6ytk1r+kkL60WI2tUV4Nfk= Subject: FAILED: patch "[PATCH] smb: client: reject FIND data areas that run past the" failed to apply to 6.6-stable tree To: diego@bynar.io,dhowells@redhat.com,pc@manguebit.org Cc: From: Date: Wed, 04 Nov 2026 13:33:57 -0500 Message-ID: <2026110457-pulsate-oil-dbd1@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 6.6-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-6.6.y git checkout FETCH_HEAD git cherry-pick -x 29bd6773187cb5c1bbbdf90d677c6add7d58af26 # git commit -s git send-email --to '' --in-reply-to '2026110457-pulsate-oil-dbd1@gregkh' --subject-prefix 'PATCH 6.6.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);