Index: srtp/crypto/cipher/aes_icm.c
===================================================================
--- srtp/crypto/cipher/aes_icm.c (revision 157386)
+++ srtp/crypto/cipher/aes_icm.c (working copy)
@@ -165,7 +165,7 @@
err_status_t
aes_icm_context_init(aes_icm_ctx_t *c, const uint8_t *key, int key_len) {
err_status_t status;
- int base_key_len;
+ int base_key_len, copy_len;
if (key_len > 16 && key_len < 30) /* Ismacryp */
base_key_len = 16;
@@ -174,15 +174,20 @@
else
return err_status_bad_param;
- /* set counter and initial values to 'offset' value */
- /* Note this copies past the end of the 'key' array by 2 bytes! */
- v128_copy_octet_string(&c->counter, key + base_key_len);
- v128_copy_octet_string(&c->offset, key + base_key_len);
+ /*
+ * set counter and initial values to 'offset' value, being careful not to
+ * go past the end of the key buffer.
+ */
+ v128_set_to_zero(&c->counter);
+ v128_set_to_zero(&c->offset);
- /* force last two octets of the offset to zero (for srtp compatibility) */
- c->offset.v8[14] = c->offset.v8[15] = 0;
- c->counter.v8[14] = c->counter.v8[15] = 0;
+ /* force last two octets of the offset to be left zero
+ * (for srtp compatibility) */
+ copy_len = key_len - base_key_len;
+ memcpy(&c->counter, key + base_key_len, copy_len);
+ memcpy(&c->offset, key + base_key_len, copy_len);
+
debug_print(mod_aes_icm,
"key: %s", octet_string_hex_string(key, base_key_len));
debug_print(mod_aes_icm,