From d6e43798b3d9cb8c59e1fccfaeec7cb396dc0699 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Fri, 27 Jul 2018 15:36:11 -0700 Subject: crypto: dh - make crypto_dh_encode_key() make robust Make it return -EINVAL if crypto_dh_key_len() is incorrect rather than overflowing the buffer. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu --- crypto/dh_helper.c | 30 ++++++++++++++++-------------- 1 file changed, 16 insertions(+), 14 deletions(-) diff --git a/crypto/dh_helper.c b/crypto/dh_helper.c index db9b2d9c58f0..edacda5f6a4d 100644 --- a/crypto/dh_helper.c +++ b/crypto/dh_helper.c @@ -16,8 +16,10 @@ #define DH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + 4 * sizeof(int)) -static inline u8 *dh_pack_data(void *dst, const void *src, size_t size) +static inline u8 *dh_pack_data(u8 *dst, u8 *end, const void *src, size_t size) { + if (!dst || size > end - dst) + return NULL; memcpy(dst, src, size); return dst + size; } @@ -42,27 +44,27 @@ EXPORT_SYMBOL_GPL(crypto_dh_key_len); int crypto_dh_encode_key(char *buf, unsigned int len, const struct dh *params) { u8 *ptr = buf; + u8 * const end = ptr + len; struct kpp_secret secret = { .type = CRYPTO_KPP_SECRET_TYPE_DH, .len = len }; - if (unlikely(!buf)) + if (unlikely(!len)) return -EINVAL; - if (len != crypto_dh_key_len(params)) + ptr = dh_pack_data(ptr, end, &secret, sizeof(secret)); + ptr = dh_pack_data(ptr, end, ¶ms->key_size, + sizeof(params->key_size)); + ptr = dh_pack_data(ptr, end, ¶ms->p_size, sizeof(params->p_size)); + ptr = dh_pack_data(ptr, end, ¶ms->q_size, sizeof(params->q_size)); + ptr = dh_pack_data(ptr, end, ¶ms->g_size, sizeof(params->g_size)); + ptr = dh_pack_data(ptr, end, params->key, params->key_size); + ptr = dh_pack_data(ptr, end, params->p, params->p_size); + ptr = dh_pack_data(ptr, end, params->q, params->q_size); + ptr = dh_pack_data(ptr, end, params->g, params->g_size); + if (ptr != end) return -EINVAL; - - ptr = dh_pack_data(ptr, &secret, sizeof(secret)); - ptr = dh_pack_data(ptr, ¶ms->key_size, sizeof(params->key_size)); - ptr = dh_pack_data(ptr, ¶ms->p_size, sizeof(params->p_size)); - ptr = dh_pack_data(ptr, ¶ms->q_size, sizeof(params->q_size)); - ptr = dh_pack_data(ptr, ¶ms->g_size, sizeof(params->g_size)); - ptr = dh_pack_data(ptr, params->key, params->key_size); - ptr = dh_pack_data(ptr, params->p, params->p_size); - ptr = dh_pack_data(ptr, params->q, params->q_size); - dh_pack_data(ptr, params->g, params->g_size); - return 0; } EXPORT_SYMBOL_GPL(crypto_dh_encode_key); -- cgit v1.2.3