FAILED: patch "[PATCH] smb: server: Fix extension string in" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-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-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 8e7d178d06e8937454b6d2f2811fa6a15656a214
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025081253-lapping-empathic-d0ae@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 8e7d178d06e8937454b6d2f2811fa6a15656a214 Mon Sep 17 00:00:00 2001
From: Thorsten Blum <[email protected]>
Date: Wed, 6 Aug 2025 03:03:49 +0200
Subject: [PATCH] smb: server: Fix extension string in
ksmbd_extract_shortname()

In ksmbd_extract_shortname(), strscpy() is incorrectly called with the length of the source string (excluding the NUL terminator) rather than the size of the destination buffer. This results in "__" being copied to 'extension' rather than "___" (two underscores instead of three).

Use the destination buffer size instead to ensure that the string "___" (three underscores) is copied correctly.

index 425c756bcfb8..b23203a1c286 100644
@@ -515,7 +515,7 @@ int ksmbd_extract_shortname(struct ksmbd_conn *conn, const char *longname,
 
 	p = strrchr(longname, '.');
 	if (p == longname) { /*name starts with a dot*/
-		strscpy(extension, "___", strlen("___"));
+		strscpy(extension, "___", sizeof(extension));
 	} else {
 		if (p) {
 			p++;