From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C4F5B3AFB1C; Fri, 4 Sep 2026 05:15:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788498940; cv=none; b=eTuGyi8siAAapuborOgpgdT8rVG6KLqzSp8KFd1gUk4SCrRBgh7BEx2NrPuZ+Q1IfmeBRB7XpRgSyrLFvqprONzemkFzNLLQg/QE+oMEWNLuBOaoWkaOLORrMaYZHLBlZ1UBg921R64vPngmF+HICu0A17UiufX3/Fq+VU1f81k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788498940; c=relaxed/simple; bh=tIrGtPvaxoP4cQeGHR2hWQrWxhdL8vURS3slTXcx/2U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IbQ/iFvPAvcmd+2dT0v9kivrmt8FIU6MASyk3ArkMttzNFmeAPBLm1gzhkIZTPVQhbaWg060VlIdj4iTTwMLGSvZr3JCqvf7l1frkQ5cZRQSv0Mgi22hQtifG2dzkwBsKTH9EkbLfXYW+5TNapFp+RpIG+2pbtHjOTg9z8QcnQM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=G05DC5LV; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="G05DC5LV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DDE3A1F00A3D; Fri, 4 Sep 2026 05:15:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788498939; bh=GlkjhbG8AJth7BXCb7oGKAzbF9vgBssNl3YvzHHFYgY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=G05DC5LV1Ou6YeuDQbHXGswbRUJBIUblL7jti7qgAaoh+Q7Vo12PTIasm4pmHPspF 0gxhWLHfUSZRC9ui7LiaM1RWeMamuUbFIeryNtB8VGB0XebISyUeqrIz3uqXGAIg4n 3pe4fH0wsc+wqx2EZu7fDvaYTyQR5ryAy335zPQ0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Shen Yongchao , Frank Sorenson , Namjae Jeon , Paulo Alcantara Subject: [PATCH 7.2 241/713] smb: client: fix OOB read/write from unvalidated DataOffset in coalesce_t2() Date: Fri, 4 Sep 2026 06:53:29 +0200 Message-ID: <20260904045809.233058711@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045803.810145556@linuxfoundation.org> References: <20260904045803.810145556@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Frank Sorenson commit 6343c1da561962688f203362d80d6a3bfa39fa1b upstream. coalesce_t2() computes data pointers directly from server-supplied DataOffset fields with no validation against buffer bounds: data_area_of_tgt = (char *)&pSMBt->hdr.Protocol + get_unaligned_le16(&pSMBt->t2_rsp.DataOffset); data_area_of_src = (char *)&pSMBs->hdr.Protocol + get_unaligned_le16(&pSMBs->t2_rsp.DataOffset); data_area_of_tgt += total_in_tgt; ... memcpy(data_area_of_tgt, data_area_of_src, total_in_src); A small DataOffset can push a pointer below the actual byte area, overwriting header fields; a large one can push it past the buffer end, causing out-of-bounds heap reads (source) or writes (target). The BCC overflow guard does not prevent this: BCC reflects how much data is present, while DataOffset controls where in the buffer it starts. The "validate target area" comment present since the function was first written in 2005 was a placeholder that was never implemented. Add lower- and upper-bound checks for both data pointers before the memcpy, and before any target header fields are modified. Fixes: e4eb295d38b5 ("[PATCH] cifs: Handle multiple response transact2 part 1 of 2") Cc: stable@vger.kernel.org Reported-by: Shen Yongchao Signed-off-by: Frank Sorenson Signed-off-by: Namjae Jeon Signed-off-by: Paulo Alcantara Signed-off-by: Greg Kroah-Hartman --- fs/smb/client/smb1transport.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) --- a/fs/smb/client/smb1transport.c +++ b/fs/smb/client/smb1transport.c @@ -375,12 +375,31 @@ coalesce_t2(char *second_buf, struct smb data_area_of_tgt = (char *)&pSMBt->hdr.Protocol + get_unaligned_le16(&pSMBt->t2_rsp.DataOffset); - /* validate target area */ data_area_of_src = (char *)&pSMBs->hdr.Protocol + get_unaligned_le16(&pSMBs->t2_rsp.DataOffset); data_area_of_tgt += total_in_tgt; + /* + * DataOffset fields are server-supplied and not validated against + * buffer bounds; check both data pointers before mutating the + * target header. + */ + if (data_area_of_tgt < (char *)target_hdr + + sizeof(struct smb_t2_rsp) + sizeof(__le16) || + data_area_of_tgt + total_in_src > + (char *)target_hdr + CIFSMaxBufSize + MAX_CIFS_HDR_SIZE) { + cifs_dbg(VFS, "%s: target data area out of bounds\n", __func__); + return -EPROTO; + } + if (data_area_of_src < second_buf + + sizeof(struct smb_t2_rsp) + sizeof(__le16) || + data_area_of_src + total_in_src > + second_buf + smbCalcSize((struct smb_hdr *)second_buf)) { + cifs_dbg(VFS, "%s: secondary data area out of bounds\n", __func__); + return -EPROTO; + } + total_in_tgt += total_in_src; /* is the result too big for the field? */ if (total_in_tgt > USHRT_MAX) {