FAILED: patch "[PATCH] smb: client: Fix next buffer leak in" failed to apply to 5.15-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.15-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 <stable@vger.kernel.org>.

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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 1c6267a1d5cf4c73b656f8181b310cbbb3e4767b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026071454-probe-applicant-d9c0@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

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

From 1c6267a1d5cf4c73b656f8181b310cbbb3e4767b Mon Sep 17 00:00:00 2001
From: Haoxiang Li <haoxiang_li2024@163.com>
Date: Tue, 23 Jun 2026 09:45:38 +0800
Subject: [PATCH] smb: client: Fix next buffer leak in
 receive_encrypted_standard()

receive_encrypted_standard() allocates next_buffer before checking
whether the number of compound PDUs already reached MAX_COMPOUND. If
the limit check fails, the function returns immediately and the newly
allocated next_buffer is not assigned to server->smallbuf/server->bigbuf,
making it leaked.

Move the MAX_COMPOUND check before allocating next_buffer.

Fixes: b24df3e30cbf ("cifs: update receive_encrypted_standard to handle compounded responses")
Cc: stable@vger.kernel.org
Signed-off-by: Haoxiang Li <haoxiang_li2024@163.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index 2964f461fc84..c862a98e52df 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -5111,6 +5111,12 @@ receive_encrypted_standard(struct TCP_Server_Info *server,
 one_more:
 	shdr = (struct smb2_hdr *)buf;
 	next_cmd = le32_to_cpu(shdr->NextCommand);
+
+	if (*num_mids >= MAX_COMPOUND) {
+		cifs_server_dbg(VFS, "too many PDUs in compound\n");
+		return -1;
+	}
+
 	if (next_cmd) {
 		if (WARN_ON_ONCE(next_cmd > pdu_length))
 			return -1;
@@ -5134,10 +5140,6 @@ receive_encrypted_standard(struct TCP_Server_Info *server,
 		mid_entry->resp_buf_size = server->pdu_size;
 	}
 
-	if (*num_mids >= MAX_COMPOUND) {
-		cifs_server_dbg(VFS, "too many PDUs in compound\n");
-		return -1;
-	}
 	bufs[*num_mids] = buf;
 	mids[(*num_mids)++] = mid_entry;