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Subject[PATCH cleanups/resubmit 4/4] crypto/rng: ensure that the RNG is ready before using
Date
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>
---
This is the same as v4/v5.

crypto/rng.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/crypto/rng.c b/crypto/rng.c
index f46dac5288b9..e042437e64b4 100644
--- a/crypto/rng.c
+++ b/crypto/rng.c
@@ -48,12 +48,14 @@ 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;
}
--
2.13.0
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