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authorAndrew Lutomirski <luto@kernel.org>2016-10-17 10:06:27 -0700
committerHerbert Xu <herbert@gondor.apana.org.au>2016-10-19 11:20:21 +0800
commit6d4952d9d9d4dc2bb9c0255d95a09405a1e958f7 (patch)
treede7c243da39513abf015bca7993dff3245467729 /drivers/char/hw_random/core.c
parent1001354ca34179f3db924eb66672442a173147dc (diff)
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/hw_random/core.c')
-rw-r--r--drivers/char/hw_random/core.c6
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)