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=1793829010; b=ltsSzT8qlKTSflngH8W7WzxuRaxOBBWWm49cbXczgK6A0bAdgpUKanVAeF6ZAQsqiSBx ak/EeJ8MtTcVaDstkjQ87BH8oj+6wJsZ/3lxHdHtHV3iFzqY3DJMvFtXjrQR+nF5KPW5L K7UJUAwnD7zsFiLqPCWMqIgfz7YQScPGReQVmAovu02/rc2gRxiZT+fsZ4IRfAA6kmqN1 C9Txwl0bP+AGIOpsvktcAXqVFgtnoZa+M0yygmP9bvQU9Mb0IEW8hfgDl6IkMx9euLsTR SqUfF6gL/Tyzn9RuuQuFQ/+pV4gjV9qhD6/blMK4dUzUXoc7sb+KMGgy5LWNoGkl9Bg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793829010; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=cX14CIww+a5jymhaGwEHBLJYZOKC6tXHUhn2OPVcEek=; b=4aThOqfnr8Q0LjUJCisygQT59LNamLNB2uDqf99o9H5PiMZvCgZ9GtHI9GIq8Ni8NbKJ iGdOweOFgh2ij4n1nmFQLMFMtuwbVYqylVs+EqmzNiwEBpWYm9RFXKn3/B4HUdaLCjqiw DwJxZkSRaD9o6qDId+vReWyt7Xfp2f1vuTKtXZ0tW8j1XyP4tYcREoXsOcqIYqL4vqANj +n+PJx1hfKE3QGkmjKeu+hcPxBMyf1xZc9tXgDoxDq0+GIWcbLongqw0USM+bashDZ0Oh E+JO8h5Qc4nCkIwVuA8sD3Giu+6XlJl+jjUVtQJeDuN3N1/SfNwiRCIJHDCtb38agaQ== 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=vKbjaQuv; 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 9E27F607F2BA; Wed, 4 Nov 2026 21:50:10 +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=vKbjaQuv Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3EC8A1F000C1; Wed, 4 Nov 2026 21:50:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793829010; bh=cX14CIww+a5jymhaGwEHBLJYZOKC6tXHUhn2OPVcEek=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=vKbjaQuvkgbmM9ACwioBLaSZwoVTO6rhnkqM8b+qecNPtcTs5teNpL2sqTsLrQElD 9P6rFjq9ivVLAJERvJVh3qeOI05yTfP5il9Oqhv71eKy7OAtLFJYiTAbkz/Fv0QTMv QhoKAV9+2CUwcuqHvjbzNDJrXU7ctMsGMfEAxsyU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Diego Oliva , David Howells , Paulo Alcantara Subject: [PATCH 7.3 385/547] smb: client: reject FIND data areas that run past the received response Date: Wed, 4 Nov 2026 16:09:29 -0500 Message-ID: <20261104211049.234800822@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211038.406938024@linuxfoundation.org> References: <20261104211038.406938024@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Diego Oliva commit 29bd6773187cb5c1bbbdf90d677c6add7d58af26 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- fs/smb/client/cifssmb.c | 31 +++++++++++++++++++++++++------ 1 file changed, 25 insertions(+), 6 deletions(-) --- a/fs/smb/client/cifssmb.c +++ b/fs/smb/client/cifssmb.c @@ -4418,8 +4418,9 @@ CIFSFindFirst(const unsigned int xid, st /* 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; @@ -4538,11 +4539,19 @@ findFirstRetry: 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)); @@ -4575,8 +4584,9 @@ int CIFSFindNext(const unsigned int xid, { 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; @@ -4660,13 +4670,22 @@ int CIFSFindNext(const unsigned int xid, 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);