Re: [PATCH] crypto/rng: ensure that the RNG is ready before using

[Herbert Xu]

On Sun, Jul 16, 2017 at 07:22:06PM +0200, Jason A. Donenfeld wrote:
> Otherwise, we might be seeding the RNG using bad randomness, which is
> dangerous. The one use of this function from within the kernel -- not
> from userspace -- is being removed (keys/big_key), so that call site
> isn't relevant in assessing this.
> 
> Cc: Herbert Xu 
> Signed-off-by: Jason A. Donenfeld 

Patch applied.  Thanks.
-- 
Email: Herbert Xu 
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

[PATCH] crypto/rng: ensure that the RNG is ready before using

[Jason A. Donenfeld]

Otherwise, we might be seeding the RNG using bad randomness, which is
dangerous. The one use of this function from within the kernel -- not
from userspace -- is being removed (keys/big_key), so that call site
isn't relevant in assessing this.

Cc: Herbert Xu 
Signed-off-by: Jason A. Donenfeld 
---
 crypto/rng.c | 6 --
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/crypto/rng.c b/crypto/rng.c
index 5e8469244960..b4a618668161 100644
--- a/crypto/rng.c
+++ b/crypto/rng.c
@@ -43,12 +43,14 @@ int crypto_rng_reset(struct crypto_rng *tfm, const u8 
*seed, unsigned int slen)
if (!buf)
return -ENOMEM;
 
-   get_random_bytes(buf, slen);
+   err = get_random_bytes_wait(buf, slen);
+   if (err)
+   goto out;
seed = buf;
}
 
err = crypto_rng_alg(tfm)->seed(tfm, seed, slen);
-
+out:
kzfree(buf);
return err;
 }
-- 
2.13.3