Commit c2176f00 authored Jul 16, 2017 by Jason A. Donenfeld Committed by Herbert Xu Jul 28, 2017

crypto: rng - ensure that the RNG is ready before using



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 <herbert@gondor.apana.org.au>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

parent 8a1012d3

crypto/rng.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -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;
		}

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