FAILED: patch "[PATCH] ksmbd: Prevent integer overflow in calculation of deadtime" 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 a93ff742820f75bf8bb3fcf21d9f25ca6eb3d4c6
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025042134-thriving-decimeter-0201@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

From a93ff742820f75bf8bb3fcf21d9f25ca6eb3d4c6 Mon Sep 17 00:00:00 2001
From: Denis Arefev <arefev@swemel.ru>
Date: Wed, 9 Apr 2025 12:04:49 +0300
Subject: [PATCH] ksmbd: Prevent integer overflow in calculation of deadtime

The user can set any value for 'deadtime'. This affects the arithmetic
expression 'req->deadtime * SMB_ECHO_INTERVAL', which is subject to
overflow. The added check makes the server behavior more predictable.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 0626e6641f6b ("cifsd: add server handler for central processing and tranport layers")
Cc: stable@vger.kernel.org
Signed-off-by: Denis Arefev <arefev@swemel.ru>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/smb/server/transport_ipc.c b/fs/smb/server/transport_ipc.c
index 3f185ae60dc5..2a3e2b0ce557 100644
--- a/fs/smb/server/transport_ipc.c
+++ b/fs/smb/server/transport_ipc.c
@@ -310,7 +310,11 @@ static int ipc_server_config_on_startup(struct ksmbd_startup_request *req)
 	server_conf.signing = req->signing;
 	server_conf.tcp_port = req->tcp_port;
 	server_conf.ipc_timeout = req->ipc_timeout * HZ;
-	server_conf.deadtime = req->deadtime * SMB_ECHO_INTERVAL;
+	if (check_mul_overflow(req->deadtime, SMB_ECHO_INTERVAL,
+					&server_conf.deadtime)) {
+		ret = -EINVAL;
+		goto out;
+	}
 	server_conf.share_fake_fscaps = req->share_fake_fscaps;
 	ksmbd_init_domain(req->sub_auth);
 
@@ -337,6 +341,7 @@ static int ipc_server_config_on_startup(struct ksmbd_startup_request *req)
 	server_conf.bind_interfaces_only = req->bind_interfaces_only;
 	ret |= ksmbd_tcp_set_interfaces(KSMBD_STARTUP_CONFIG_INTERFACES(req),
 					req->ifc_list_sz);
+out:
 	if (ret) {
 		pr_err("Server configuration error: %s %s %s\n",
 		       req->netbios_name, req->server_string,