From 973c39115cb308b6b1fe64b4f342996f3eef06d0 Mon Sep 17 00:00:00 2001
From: Joe Perches <joe@perches.com>
Date: Wed, 16 Sep 2020 13:40:40 -0700
Subject: [PATCH] drivers core: Remove strcat uses around sysfs_emit and neaten
Git-commit: 973c39115cb308b6b1fe64b4f342996f3eef06d0
Patch-mainline: v5.10-rc1
References: bsc#1200598 CVE-2022-20166

strcat is no longer necessary for sysfs_emit and sysfs_emit_at uses.

Convert the strcat uses to sysfs_emit calls and neaten other block
uses of direct returns to use an intermediate const char *.

Signed-off-by: Joe Perches <joe@perches.com>
Link: https://lore.kernel.org/r/5d606519698ce4c8f1203a2b35797d8254c6050a.1600285923.git.joe@perches.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Petr Mladek <pmladek@suse.com>

[ pmladek@suse.com: Removed changes where the buffer could never overflow. ]
---
 drivers/base/memory.c |   13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -396,6 +396,7 @@ static ssize_t show_valid_zones(struct d
 	unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
 	unsigned long valid_start_pfn, valid_end_pfn;
 	bool append = false;
+	int len = 0;
 	int nid;
 
 	/*
@@ -416,25 +416,25 @@ static ssize_t show_valid_zones(struct d
 					  &valid_start_pfn, &valid_end_pfn))
 			return sysfs_emit(buf, "none\n");
 		start_pfn = valid_start_pfn;
-		strcat(buf, page_zone(pfn_to_page(start_pfn))->name);
+		len += sysfs_emit_at(buf, len, "%s", page_zone(pfn_to_page(start_pfn))->name);
 		goto out;
 	}
 
 	nid = mem->nid;
 	if (allow_online_pfn_range(nid, start_pfn, nr_pages, MMOP_ONLINE_KERNEL)) {
-		strcat(buf, default_zone_for_pfn(nid, start_pfn, nr_pages)->name);
+		len += sysfs_emit_at(buf, len, "%s", default_zone_for_pfn(nid, start_pfn, nr_pages)->name);
 		append = true;
 	}
 
 	if (allow_online_pfn_range(nid, start_pfn, nr_pages, MMOP_ONLINE_MOVABLE)) {
 		if (append)
-			strcat(buf, " ");
-		strcat(buf, NODE_DATA(nid)->node_zones[ZONE_MOVABLE].name);
+			len += sysfs_emit_at(buf, len, " ");
+		len += sysfs_emit_at(buf, len, "%s", NODE_DATA(nid)->node_zones[ZONE_MOVABLE].name);
 	}
 out:
-	strcat(buf, "\n");
+	len += sysfs_emit_at(buf, len, "\n");
 
-	return strlen(buf);
+	return len;
 }
 static DEVICE_ATTR(valid_zones, 0444, show_valid_zones, NULL);
 #endif