Fix SSKDF to not claim a buffer size that is too small for the MAC
We also check that our buffer is sufficiently sized for the MAC output
@@ -239,7 +239,7 @@ static int SSKDF_mac_kdm(EVP_MAC_CTX *ctx_init,
goto end;
out_len = EVP_MAC_CTX_get_mac_size(ctx_init); /* output size */
- if (out_len <= 0)
+ if (out_len <= 0 || (mac == mac_buf && out_len > sizeof(mac_buf)))
goto end;
len = derived_key_len;
@@ -263,7 +263,7 @@ static int SSKDF_mac_kdm(EVP_MAC_CTX *ctx_init,
if (len == 0)
break;
} else {
- if (!EVP_MAC_final(ctx, mac, NULL, len))
+ if (!EVP_MAC_final(ctx, mac, NULL, out_len))
goto end;
memcpy(out, mac, len);
break;
