Commit ccd9888f authored Nov 05, 2017 by Eric Biggers Committed by Herbert Xu Nov 10, 2017

crypto: dh - Don't permit 'key' or 'g' size longer than 'p'



The "qat-dh" DH implementation assumes that 'key' and 'g' can be copied
into a buffer with size 'p_size'.  However it was never checked that
that was actually the case, which most likely allowed users to cause a
buffer underflow via KEYCTL_DH_COMPUTE.

Fix this by updating crypto_dh_decode_key() to verify this precondition
for all DH implementations.

Fixes: c9839143 ("crypto: qat - Add DH support")
Cc: <stable@vger.kernel.org> # v4.8+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

parent 199512b1

crypto/dh_helper.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -83,6 +83,14 @@ int crypto_dh_decode_key(const char buf, unsigned int len, struct dh params)
		if (secret.len != crypto_dh_key_len(params))
		return -EINVAL;

		/*
		* Don't permit the buffer for 'key' or 'g' to be larger than 'p', since
		* some drivers assume otherwise.
		*/
		if (params->key_size > params->p_size \|\|
		params->g_size > params->p_size)
		return -EINVAL;

		/* Don't allocate memory. Set pointers to data within
		* the given buffer
		*/