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Commit 6d4952d9 authored by Andrew Lutomirski's avatar Andrew Lutomirski Committed by Herbert Xu
Browse files

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: default avatarMatt Mullins <mmullins@mmlx.us>
Tested-by: default avatarMatt Mullins <mmullins@mmlx.us>
Fixes: d3cc7996 ("hwrng: fetch randomness only after device init")
Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 1001354c

drivers/char/hw_random/core.c

+3 −3
Original line number Diff line number Diff line
@@ -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)