From: Pierre <pinaraf@pinaraf.info>
Date: Sun, 12 Nov 2017 14:24:32 +0000 (+0100)
Subject: crypto: ecc - Fix NULL pointer deref. on no default_rng
X-Git-Tag: Ubuntu-4.15.0-14.15~527
X-Git-Url: https://git.proxmox.com/?p=mirror_ubuntu-bionic-kernel.git;a=commitdiff_plain;h=2341559f4d5ec3b5d009313e8a865759199eada2

crypto: ecc - Fix NULL pointer deref. on no default_rng


BugLink: http://bugs.launchpad.net/bugs/1756978

[ 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>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
---

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();