More forceful clearing of stack memory with keys

gcc 8.3.0 was apparently clever enough to optimize away the previously
used os_memset() to explicitly clear a stack buffer that contains keys
when that clearing happened just before returning from the function.
Since memset_s() is not exactly portable (or commonly available yet..),
use a less robust mechanism that is still pretty likely to prevent
current compilers from optimizing the explicit clearing of the memory
away.

Signed-off-by: Jouni Malinen <j@w1.fi>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/crypto/sha1-internal.c b/src/crypto/sha1-internal.c
index a491707..ffa04df 100644
--- a/src/crypto/sha1-internal.c
+++ b/src/crypto/sha1-internal.c
@@ -224,7 +224,7 @@ void SHA1Transform(u32 state[5], const unsigned char buffer[64])
 	/* Wipe variables */
 	a = b = c = d = e = 0;
 #ifdef SHA1HANDSOFF
-	os_memset(block, 0, 64);
+	forced_memzero(block, 64);
 #endif
 }
 
@@ -300,7 +300,7 @@ void SHA1Final(unsigned char digest[20], SHA1_CTX* context)
 	os_memset(context->buffer, 0, 64);
 	os_memset(context->state, 0, 20);
 	os_memset(context->count, 0, 8);
-	os_memset(finalcount, 0, 8);
+	forced_memzero(finalcount, sizeof(finalcount));
 }
 
 /* ===== end - public domain SHA1 implementation ===== */