diff options
| author | Andrew Lutomirski <luto@kernel.org> | 2016-10-17 10:06:27 -0700 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2017-02-23 03:54:17 +0000 |
| commit | 2cd8816eccf2fb56d19d0e8751e451eb980815f3 (patch) | |
| tree | 7e2f548858949d2fc322518934e0e5b8d15b46e7 | |
| parent | 91dd2474f37e9e1dcd4c0c9c51891fc50edbad8c (diff) | |
hwrng: core - Don't use a stack buffer in add_early_randomness()
commit 6d4952d9d9d4dc2bb9c0255d95a09405a1e958f7 upstream.
hw_random carefully avoids using a stack buffer except in
add_early_randomness(). This causes a crash in virtio_rng if
CONFIG_VMAP_STACK=y.
Reported-by: Matt Mullins <mmullins@mmlx.us>
Tested-by: Matt Mullins <mmullins@mmlx.us>
Fixes: d3cc7996473a ("hwrng: fetch randomness only after device init")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | drivers/char/hw_random/core.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index 2a451b14b3cc..d456303f4625 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -65,12 +65,12 @@ static size_t rng_buffer_size(void) static void add_early_randomness(struct hwrng *rng) { - unsigned char bytes[16]; int bytes_read; + size_t size = min_t(size_t, 16, rng_buffer_size()); - bytes_read = rng_get_data(rng, bytes, sizeof(bytes), 1); + bytes_read = rng_get_data(rng, rng_buffer, size, 1); if (bytes_read > 0) - add_device_randomness(bytes, bytes_read); + add_device_randomness(rng_buffer, bytes_read); } static inline int hwrng_init(struct hwrng *rng) |