Thread (6 messages) 6 messages, 3 authors, 2017-12-20
STALE3203d

[PATCH] Fix NULL pointer deref. on no default_rng

From: Pierre Ducroquet <hidden>
Date: 2017-11-12 14:31:39
Subsystem: asymmetric keys - ecdsa, crypto api, the rest · Maintainers: Lukas Wunner, Ignat Korchagin, Herbert Xu, "David S. Miller", Linus Torvalds

If crypto_get_default_rng returns an error, the
function ecc_gen_privkey should return an error.
Instead, it currently tries to use the default_rng
nevertheless, thus creating a kernel panic with a
NULL pointer dereference.
Returning the error directly, as was supposedly
intended when looking at the code, fixes this.

Signed-off-by: Pierre Ducroquet <redacted>
---
 crypto/ecc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/crypto/ecc.c b/crypto/ecc.c
index 633a9bcdc574..18f32f2a5e1c 100644
--- a/crypto/ecc.c
+++ b/crypto/ecc.c
@@ -964,7 +964,7 @@ int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits, u64 *privkey)
 	 * DRBG with a security strength of 256.
 	 */
 	if (crypto_get_default_rng())
-		err = -EFAULT;
+		return -EFAULT;
 
 	err = crypto_rng_get_bytes(crypto_default_rng, (u8 *)priv, nbytes);
 	crypto_put_default_rng();
-- 
2.15.0
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