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 8C1C218787A; Sat, 17 Oct 2026 16:49:19 +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=1792255760; cv=none; b=SBV2SxatcNItGMcwdKWdEyjAiVR30WtaN15hc0+1KjKB6cUGYxZ9ScvudGrAm5eyL7YxF3ZFyOeg/wHkCztaA2U4o8TH4Q9c3K0miCXoiq6VOH7a35F4Vt6qY7/h9NKFnwmwSUKTYXqUblEplmqT22mpEDS4zqfrpyWah+oGqEs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792255760; c=relaxed/simple; bh=04OiL7Skt3UtSOcPrNR1HaEidnqnc43ODrlL3strWik=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=U0WA7hNUCt4285bXeAf7BMyCI8XuHPnr4iJBsJMpclNEXSXijUy1xDMa/0la//b7wibPgpPYYAn/72DQu4hphHYWqzamLhQ1OM46y+6HtZ8r3EZaFqBtNEKNq+hNAKqgD4a5uP3BuIqitmRbAZ0aDZPLTFmSY1Wm1u7wgS0Wpck= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PZsD6gh+; 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="PZsD6gh+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D91C61F000C4; Sat, 17 Oct 2026 16:49:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792255759; bh=LaAhrH9UetlHisZ0fVN5dO5HYvI4XshAdpENymLOT4I=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=PZsD6gh+n3FjwUmMxMfNS+99IJWa99bTklHKmhqNAq622m2rIGP003tT7qjO6De53 AsNqgDV+dVLBt4dKGxy+hakZMjk1qpxgJXMyLvvDRfbJXH3JVkOlRC1l9BLL71YzvX fRVbMj5k64h2kUUeqdT83g/ucsQO6OB+0+bZjtc8= 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 , Sasha Levin Subject: [PATCH 6.6 0013/1674] smb: client: fix OOB read/write from unvalidated DataOffset in coalesce_t2() Date: Sat, 17 Oct 2026 17:38:05 +0200 Message-ID: <20261017160431.481808351@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160431.119607952@linuxfoundation.org> References: <20261017160431.119607952@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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Frank Sorenson [ Upstream commit 6343c1da561962688f203362d80d6a3bfa39fa1b ] 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 [ transplanted the bounds validation to coalesce_t2() in smb1ops.c due to code relocation ] Signed-off-by: Sasha Levin --- fs/smb/client/smb1ops.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/fs/smb/client/smb1ops.c b/fs/smb/client/smb1ops.c index 6acadfcbadc8e..ef71c0eb8704a 100644 --- a/fs/smb/client/smb1ops.c +++ b/fs/smb/client/smb1ops.c @@ -325,12 +325,31 @@ coalesce_t2(char *second_buf, struct smb_hdr *target_hdr) 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) { -- 2.53.0