[PATCH 01/14] crypto: drbg - Don't use uninitialized stack data

[Eric Biggers <ebiggers@kernel.org>]

If jitterentropy fails, then uninitialized stack data is mixed into the
DRBG.  While theoretically okay, this is undefined behavior and isn't
allowed by KMSAN.  Fix it by zero-initializing the buffer.

Fixes: 97f2650e5040 ("crypto: drbg - always seeded with SP800-90B compliant noise source")
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 crypto/drbg.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crypto/drbg.c b/crypto/drbg.c
index d66c7211d6bb0..e057b00e74f5b 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -230,7 +230,7 @@ static int drbg_seed(struct drbg_state *drbg, const u8 *pers, size_t pers_len,
 	__must_hold(&drbg->drbg_mutex)
 {
 	int ret;
-	u8 entropy_buf[(32 + 16) * 2];
+	u8 entropy_buf[(32 + 16) * 2] = {};
 	size_t entropylen;
 	const u8 *entropy;
 
-- 
2.56.0