case EVP_CTRL_AEAD_TLS1_AAD:
{
unsigned char *p = ptr;
- unsigned int len = p[arg - 2] << 8 | p[arg - 1];
+ unsigned int len;
+
+ if (arg != EVP_AEAD_TLS1_AAD_LEN)
+ return -1;
+
+ len = p[arg - 2] << 8 | p[arg - 1];
if (!ctx->encrypt) {
len -= MD5_DIGEST_LENGTH;