drivers/leds/leds-lp5521.c: fix potential buffer overflow

The code doesn't check first sscanf() return value.  If first sscanf()
failed then c contains some garbage.  It might lead to reading
uninitialised stack data in the second sscanf() call.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/leds/leds-lp5521.c b/drivers/leds/leds-lp5521.c
index 33facd0c45d1..e881a75dc39d 100644
--- a/drivers/leds/leds-lp5521.c
+++ b/drivers/leds/leds-lp5521.c
@@ -373,6 +373,8 @@ static int lp5521_do_store_load(struct lp5521_engine *engine,
         while ((offset < len - 1) && (i < LP5521_PROGRAM_LENGTH)) {
                 /* separate sscanfs because length is working only for %s */
                 ret = sscanf(buf + offset, "%2s%n ", c, &nrchars);
+                if (ret != 2)
+                        goto fail;
                 ret = sscanf(c, "%2x", &cmd);
                 if (ret != 1)
                         goto fail;