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authorEric Biggers <ebiggers@google.com>2018-07-28 01:36:11 +0300
committerHerbert Xu <herbert@gondor.apana.org.au>2018-08-03 13:06:06 +0300
commitd6e43798b3d9cb8c59e1fccfaeec7cb396dc0699 (patch)
tree555f72d96ffaceafe726c15b10f529eed89bf54b
parent35f7d5225ffcbf1b759f641aec1735e3a89b1914 (diff)
downloadlinux-d6e43798b3d9cb8c59e1fccfaeec7cb396dc0699.tar.xz
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 <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
-rw-r--r--crypto/dh_helper.c30
1 files 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, &params->key_size,
+ sizeof(params->key_size));
+ ptr = dh_pack_data(ptr, end, &params->p_size, sizeof(params->p_size));
+ ptr = dh_pack_data(ptr, end, &params->q_size, sizeof(params->q_size));
+ ptr = dh_pack_data(ptr, end, &params->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, &params->key_size, sizeof(params->key_size));
- ptr = dh_pack_data(ptr, &params->p_size, sizeof(params->p_size));
- ptr = dh_pack_data(ptr, &params->q_size, sizeof(params->q_size));
- ptr = dh_pack_data(ptr, &params->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);