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| author |   Andrew Lutomirski <luto@kernel.org> | 2016-10-17 10:06:27 -0700 |
|---|---|---|
| committer |   Herbert Xu <herbert@gondor.apana.org.au> | 2016-10-19 11:20:21 +0800 |
| commit | 6d4952d9d9d4dc2bb9c0255d95a09405a1e958f7 (patch) | |
| tree | de7c243da39513abf015bca7993dff3245467729 /drivers/char | |
| parent | Linux 4.9-rc1 (diff) | |
| download | linux-dev-6d4952d9d9d4dc2bb9c0255d95a09405a1e958f7.tar.xz linux-dev-6d4952d9d9d4dc2bb9c0255d95a09405a1e958f7.zip | |
hwrng: core - Don't use a stack buffer in add_early_randomness()
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>
Diffstat (limited to 'drivers/char')
| -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 482794526e8c..d2d2c89de5b4 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -84,14 +84,14 @@ 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()); mutex_lock(&reading_mutex); - bytes_read = rng_get_data(rng, bytes, sizeof(bytes), 1); + bytes_read = rng_get_data(rng, rng_buffer, size, 1); mutex_unlock(&reading_mutex); if (bytes_read > 0) - add_device_randomness(bytes, bytes_read); + add_device_randomness(rng_buffer, bytes_read); } static inline void cleanup_rng(struct kref *kref) |