From: Eric Biggers <[email protected]> It was forgotten to increase DH_KPP_SECRET_MIN_SIZE to include 'q_size', causing an out-of-bounds write of 4 bytes in crypto_dh_encode_key(), and an out-of-bounds read of 4 bytes in crypto_dh_decode_key(). Fix it. Also add a BUG_ON() if crypto_dh_encode_key() doesn't exactly fill the buffer, as that would have found this bug without resorting to KASAN.
Reported-by: [email protected] Fixes: e3fe0ae12962 ("crypto: dh - add public key verification test") Signed-off-by: Eric Biggers <[email protected]> --- crypto/dh_helper.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/crypto/dh_helper.c b/crypto/dh_helper.c index a7de3d9ce5ace..87ad6e2e87644 100644 --- a/crypto/dh_helper.c +++ b/crypto/dh_helper.c @@ -14,7 +14,7 @@ #include <crypto/dh.h> #include <crypto/kpp.h> -#define DH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + 3 * sizeof(int)) +#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) { @@ -61,7 +61,8 @@ int crypto_dh_encode_key(char *buf, unsigned int len, const struct dh *params) 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); + ptr = dh_pack_data(ptr, params->g, params->g_size); + BUG_ON(ptr != (u8 *)buf + len); return 0; } -- 2.18.0
