From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 9 Apr 2020 15:04:26 +0200
Subject: efi/cper: Use scnprintf() for avoiding potential buffer overflow
Patch-mainline: v5.7-rc2
Git-commit: b450b30b97010e5c68ab522c6f6c54ef76bd0683
References: jsc#SLE-16407

Since snprintf() returns the would-be-output size instead of the
actual output size, the succeeding calls may go beyond the given
buffer limit.  Fix it by replacing with scnprintf().

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200311072145.5001-1-tiwai@suse.de
Link: https://lore.kernel.org/r/20200409130434.6736-2-ardb@kernel.org
Acked-by: Lee, Chun-Yi <jlee@suse.com>
---
 drivers/firmware/efi/cper.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/firmware/efi/cper.c
+++ b/drivers/firmware/efi/cper.c
@@ -101,7 +101,7 @@ void cper_print_bits(const char *pfx, un
 		if (!len)
 			len = snprintf(buf, sizeof(buf), "%s%s", pfx, str);
 		else
-			len += snprintf(buf+len, sizeof(buf)-len, ", %s", str);
+			len += scnprintf(buf+len, sizeof(buf)-len, ", %s", str);
 	}
 	if (len)
 		printk("%s\n", buf);