Use IV length of a crypter instead of block size for IV calculations

[strongswan.git] / src / libtls / tls_protection.c

diff --git a/src/libtls/tls_protection.c b/src/libtls/tls_protection.c
index 5ea0a83..107751e 100644 (file)
--- a/src/libtls/tls_protection.c
+++ b/src/libtls/tls_protection.c
@@ -112,23 +112,24 @@ METHOD(tls_protection_t, process, status_t,
                u_int8_t bs, padding_length;
 
                bs = this->crypter_in->get_block_size(this->crypter_in);
-               if (data.len < bs || data.len % bs)
-               {
-                       DBG1(DBG_IKE, "encrypted TLS record not multiple of block size");
-                       return FAILED;
-               }
                if (this->iv_in.len)
                {       /* < TLSv1.1 uses IV from key derivation/last block */
+                       if (data.len < bs || data.len % bs)
+                       {
+                               DBG1(DBG_IKE, "encrypted TLS record length invalid");
+                               return FAILED;
+                       }
                        iv = this->iv_in;
                        next_iv = chunk_clone(chunk_create(data.ptr + data.len - bs, bs));
                }
                else
                {       /* TLSv1.1 uses random IVs, prepended to record */
-                       iv = chunk_create(data.ptr, bs);
-                       data = chunk_skip(data, bs);
-                       if (data.len < bs)
+                       iv.len = this->crypter_in->get_iv_size(this->crypter_in);
+                       iv = chunk_create(data.ptr, iv.len);
+                       data = chunk_skip(data, iv.len);
+                       if (data.len < bs || data.len % bs)
                        {
-                               DBG1(DBG_IKE, "TLS record too short to decrypt");
+                               DBG1(DBG_IKE, "encrypted TLS record length invalid");
                                return FAILED;
                        }
                }
@@ -231,7 +232,8 @@ METHOD(tls_protection_t, build, status_t,
                                                free(data->ptr);
                                                return FAILED;
                                        }
-                                       this->rng->allocate_bytes(this->rng, bs, &iv);
+                                       iv.len = this->crypter_out->get_iv_size(this->crypter_out);
+                                       this->rng->allocate_bytes(this->rng, iv.len, &iv);
                                }
 
                                *data = chunk_cat("mmcc", *data, mac, padding,
@@ -241,8 +243,8 @@ METHOD(tls_protection_t, build, status_t,
 
                                if (this->iv_out.len)
                                {       /* next record IV is last ciphertext block of this record */
-                                       memcpy(this->iv_out.ptr, data->ptr - this->iv_out.len,
-                                                  this->iv_out.len);
+                                       memcpy(this->iv_out.ptr, data->ptr + data->len -
+                                                  this->iv_out.len, this->iv_out.len);
                                }
                                else
                                {       /* prepend IV */
@@ -254,8 +256,8 @@ METHOD(tls_protection_t, build, status_t,
                                *data = chunk_cat("mm", *data, mac);
                        }
                }
+               this->seq_out++;
        }
-       this->seq_out++;
        return status;
 }