FAILED: patch "[PATCH] smb: client: fix missing iov bounds check in" failed to apply to 6.1-stable tree

The patch below does not apply to the 6.1-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 <[email protected]>.

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-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x b09d092eb24ad0110f16a9b7c1ed5d2a0c1733dc
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026092244-scalded-wanting-c9bc@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b09d092eb24ad0110f16a9b7c1ed5d2a0c1733dc Mon Sep 17 00:00:00 2001
From: Frank Sorenson <[email protected]>
Date: Wed, 16 Sep 2026 16:33:58 -0500
Subject: [PATCH] smb: client: fix missing iov bounds check in
parse_posix_sids()

In parse_posix_sids(), sidsbuf_end is calculated using the server-supplied out_len without being validated against the actual length of the received iov (iov_len).

If a server provides an inflated out_len, sidsbuf_end will point past the end of the iov. This defeats the bounds guards in posix_info_sid_size(), allowing out-of-bounds reads into adjacent kernel memory.

Fix this by rejecting responses where the calculated sidsbuf_end would exceed the received iov boundaries or cause pointer wraparound.

index 96063e355186..13fe8e3b48f3 100644
@@ -77,6 +77,17 @@ static int parse_posix_sids(struct cifs_open_info_data *data,
 
 	sidsbuf = (u8 *)qi + le16_to_cpu(qi->OutputBufferOffset) + qi_len;
 	sidsbuf_end = sidsbuf + out_len - qi_len;
+	if (sidsbuf_end < sidsbuf) {
+		cifs_dbg(VFS, "%s: server-supplied out_len %u caused pointer wraparound\n",
+			 __func__, out_len);
+		return -EINVAL;
+	}
+	if (sidsbuf_end > (u8 *)rsp_iov->iov_base + rsp_iov->iov_len) {
+		cifs_dbg(VFS, "%s: server-supplied out_len %u overruns iov by %td bytes\n",
+			 __func__, out_len,
+			 sidsbuf_end - ((u8 *)rsp_iov->iov_base + rsp_iov->iov_len));
+		return -EINVAL;
+	}
 
 	owner_len = posix_info_sid_size(sidsbuf, sidsbuf_end);
 	if (owner_len == -1)