1 files changed, 153 insertions, 0 deletions
diff --git a/third_party/libsrtp/src/crypto/cipher/null_cipher.c b/third_party/libsrtp/src/crypto/cipher/null_cipher.c
new file mode 100644
index 0000000000..969724611c
--- /dev/null
+++ b/third_party/libsrtp/src/crypto/cipher/null_cipher.c
@@ -0,0 +1,153 @@
+/*
+ * null_cipher.c
+ *
+ * A null cipher implementation.  This cipher leaves the plaintext
+ * unchanged.
+ *
+ * David A. McGrew
+ * Cisco Systems, Inc.
+ */
+
+/*
+ *
+ * Copyright (c) 2001-2017 Cisco Systems, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ *   Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ *   Neither the name of the Cisco Systems, Inc. nor the names of its
+ *   contributors may be used to endorse or promote products derived
+ *   from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "datatypes.h"
+#include "null_cipher.h"
+#include "err.h" /* for srtp_debug */
+#include "alloc.h"
+#include "cipher_types.h"
+
+static srtp_err_status_t srtp_null_cipher_alloc(srtp_cipher_t **c,
+                                                int key_len,
+                                                int tlen)
+{
+    extern const srtp_cipher_type_t srtp_null_cipher;
+
+    debug_print(srtp_mod_cipher, "allocating cipher with key length %d",
+                key_len);
+
+    /* allocate memory a cipher of type null_cipher */
+    *c = (srtp_cipher_t *)srtp_crypto_alloc(sizeof(srtp_cipher_t));
+    if (*c == NULL) {
+        return srtp_err_status_alloc_fail;
+    }
+
+    /* set pointers */
+    (*c)->algorithm = SRTP_NULL_CIPHER;
+    (*c)->type = &srtp_null_cipher;
+    (*c)->state = (void *)0x1; /* The null cipher does not maintain state */
+
+    /* set key size */
+    (*c)->key_len = key_len;
+
+    return srtp_err_status_ok;
+}
+
+static srtp_err_status_t srtp_null_cipher_dealloc(srtp_cipher_t *c)
+{
+    extern const srtp_cipher_type_t srtp_null_cipher;
+
+    /* zeroize entire state*/
+    octet_string_set_to_zero(c, sizeof(srtp_cipher_t));
+
+    /* free memory of type null_cipher */
+    srtp_crypto_free(c);
+
+    return srtp_err_status_ok;
+}
+
+static srtp_err_status_t srtp_null_cipher_init(void *cv, const uint8_t *key)
+{
+    /* srtp_null_cipher_ctx_t *c = (srtp_null_cipher_ctx_t *)cv; */
+
+    debug_print0(srtp_mod_cipher, "initializing null cipher");
+
+    return srtp_err_status_ok;
+}
+
+static srtp_err_status_t srtp_null_cipher_set_iv(void *cv,
+                                                 uint8_t *iv,
+                                                 srtp_cipher_direction_t dir)
+{
+    /* srtp_null_cipher_ctx_t *c = (srtp_null_cipher_ctx_t *)cv; */
+    return srtp_err_status_ok;
+}
+
+static srtp_err_status_t srtp_null_cipher_encrypt(void *cv,
+                                                  unsigned char *buf,
+                                                  unsigned int *bytes_to_encr)
+{
+    /* srtp_null_cipher_ctx_t *c = (srtp_null_cipher_ctx_t *)cv; */
+    return srtp_err_status_ok;
+}
+
+static const char srtp_null_cipher_description[] = "null cipher";
+
+static const srtp_cipher_test_case_t srtp_null_cipher_test_0 = {
+    0,    /* octets in key            */
+    NULL, /* key                      */
+    0,    /* packet index             */
+    0,    /* octets in plaintext      */
+    NULL, /* plaintext                */
+    0,    /* octets in plaintext      */
+    NULL, /* ciphertext               */
+    0,    /* */
+    NULL, /* */
+    0,    /* */
+    NULL  /* pointer to next testcase */
+};
+
+/*
+ * note: the decrypt function is idential to the encrypt function
+ */
+
+const srtp_cipher_type_t srtp_null_cipher = {
+    srtp_null_cipher_alloc,       /* */
+    srtp_null_cipher_dealloc,     /* */
+    srtp_null_cipher_init,        /* */
+    0,                            /* set_aad */
+    srtp_null_cipher_encrypt,     /* */
+    srtp_null_cipher_encrypt,     /* */
+    srtp_null_cipher_set_iv,      /* */
+    0,                            /* get_tag */
+    srtp_null_cipher_description, /* */
+    &srtp_null_cipher_test_0,     /* */
+    SRTP_NULL_CIPHER              /* */
+};