[PATCH 1/9] efi/cper: Use scnprintf() for avoiding potential buffer overflow

Ard Biesheuvel
2020-04-09T13:05:00Z

From: Takashi Iwai <tiwai@suse.de>

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>
Link: https://lore.kernel.org/r/20200311072145.5001-1-tiwai@suse.de
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
drivers/firmware/efi/cper.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
index b1af0de2e100..9d2512913d25 100644
--- a/drivers/firmware/efi/cper.c
+++ b/drivers/firmware/efi/cper.c
@@ -101,7 +101,7 @@ void cper_print_bits(const char *pfx, unsigned int bits,
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);
--
2.17.1