Move key/IV length checks closer to usage sites.

Also add explicit checks against EVP_CIPHER_iv_length() and
EVP_CIPHER_key_length().

Requested by tb@ during review.

ok tb@

diff --git a/lib/libssl/tls12_record_layer.c b/lib/libssl/tls12_record_layer.c
index d69370d..a7bd4ce 100644 (file)
--- a/lib/libssl/tls12_record_layer.c
+++ b/lib/libssl/tls12_record_layer.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls12_record_layer.c,v 1.20 2021/03/02 17:16:44 jsing Exp $ */
+/* $OpenBSD: tls12_record_layer.c,v 1.21 2021/03/02 17:18:59 jsing Exp $ */
 /*
  * Copyright (c) 2020 Joel Sing <jsing@openbsd.org>
  *
@@ -425,11 +425,18 @@ tls12_record_layer_ccs_cipher(struct tls12_record_layer *rl,
        int ret = 0;
 
        if (!tls12_record_protection_unused(rp))
-               return 0;
+               goto err;
 
        mac_type = EVP_PKEY_HMAC;
        rp->stream_mac = 0;
 
+       if (iv_len > INT_MAX || key_len > INT_MAX)
+               goto err;
+       if (EVP_CIPHER_iv_length(rl->cipher) != iv_len)
+               goto err;
+       if (EVP_CIPHER_key_length(rl->cipher) != key_len)
+               goto err;
+
        /* Special handling for GOST... */
        if (EVP_MD_type(rl->mac_hash) == NID_id_Gost28147_89_MAC) {
                if (mac_key_len != 32)
@@ -437,6 +444,8 @@ tls12_record_layer_ccs_cipher(struct tls12_record_layer *rl,
                mac_type = EVP_PKEY_GOSTIMIT;
                rp->stream_mac = 1;
        } else {
+               if (mac_key_len > INT_MAX)
+                       goto err;
                if (EVP_MD_size(rl->mac_hash) != mac_key_len)
                        goto err;
        }
@@ -492,9 +501,6 @@ tls12_record_layer_change_cipher_state(struct tls12_record_layer *rl,
     size_t mac_key_len, const uint8_t *key, size_t key_len, const uint8_t *iv,
     size_t iv_len)
 {
-       if (mac_key_len > INT_MAX || key_len > INT_MAX || iv_len > INT_MAX)
-               return 0;
-
        if (rl->aead != NULL)
                return tls12_record_layer_ccs_aead(rl, rp, is_write, mac_key,
                    mac_key_len, key, key_len, iv, iv_len);