FAILED: patch "[PATCH] ksmbd: fix out-of-bound read in smb2_write" 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 5fe7f7b78290638806211046a99f031ff26164e1
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023062136-xbox-tidal-465b@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

From 5fe7f7b78290638806211046a99f031ff26164e1 Mon Sep 17 00:00:00 2001
From: Namjae Jeon <linkinjeon@kernel.org>
Date: Thu, 15 Jun 2023 22:04:40 +0900
Subject: [PATCH] ksmbd: fix out-of-bound read in smb2_write

ksmbd_smb2_check_message doesn't validate hdr->NextCommand. If
->NextCommand is bigger than Offset + Length of smb2 write, It will
allow oversized smb2 write length. It will cause OOB read in smb2_write.

Cc: stable@vger.kernel.org
Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-21164
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/smb/server/smb2misc.c b/fs/smb/server/smb2misc.c
index 57749f41b991..33b7e6c4ceff 100644
--- a/fs/smb/server/smb2misc.c
+++ b/fs/smb/server/smb2misc.c
@@ -351,10 +351,16 @@ int ksmbd_smb2_check_message(struct ksmbd_work *work)
 	int command;
 	__u32 clc_len;  /* calculated length */
 	__u32 len = get_rfc1002_len(work->request_buf);
-	__u32 req_struct_size;
+	__u32 req_struct_size, next_cmd = le32_to_cpu(hdr->NextCommand);
 
-	if (le32_to_cpu(hdr->NextCommand) > 0)
-		len = le32_to_cpu(hdr->NextCommand);
+	if ((u64)work->next_smb2_rcv_hdr_off + next_cmd > len) {
+		pr_err("next command(%u) offset exceeds smb msg size\n",
+				next_cmd);
+		return 1;
+	}
+
+	if (next_cmd > 0)
+		len = next_cmd;
 	else if (work->next_smb2_rcv_hdr_off)
 		len -= work->next_smb2_rcv_hdr_off;