From ccd9888f14a8019c0bbdeeae758aba1f58693712 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Sun, 5 Nov 2017 18:30:46 -0800 Subject: 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: c9839143ebbf ("crypto: qat - Add DH support") Cc: # v4.8+ Signed-off-by: Eric Biggers Reviewed-by: Tudor Ambarus Signed-off-by: Herbert Xu --- crypto/dh_helper.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'crypto/dh_helper.c') diff --git a/crypto/dh_helper.c b/crypto/dh_helper.c index 788a9e572918..24fdb2ecaa85 100644 --- a/crypto/dh_helper.c +++ b/crypto/dh_helper.c @@ -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 */ -- cgit v1.2.3-55-g7522