[PATCH 4.15 049/128] crypto: ecc - Fix NULL pointer deref. on no default_rng

Greg Kroah-Hartman
2018-03-16T15:23:10Z

From: Pierre <pinaraf@pinaraf.info>

[ Upstream commit 4c0e22c90510308433272d7ba281b1eb4eda8209 ]

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 <pinaraf@pinaraf.info>
Reviewed-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
crypto/ecc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/crypto/ecc.c
+++ b/crypto/ecc.c
@@ -964,7 +964,7 @@ int ecc_gen_privkey(unsigned int curve_i
* 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();