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| 1 /* | |
| 2 * ekt.h | |
| 3 * | |
| 4 * interface to Encrypted Key Transport for SRTP | |
| 5 * | |
| 6 * David McGrew | |
| 7 * Cisco Systems, Inc. | |
| 8 */ | |
| 9 /* | |
| 10 * | |
| 11 * Copyright (c) 2001-2005 Cisco Systems, Inc. | |
| 12 * All rights reserved. | |
| 13 * | |
| 14 * Redistribution and use in source and binary forms, with or without | |
| 15 * modification, are permitted provided that the following conditions | |
| 16 * are met: | |
| 17 * | |
| 18 * Redistributions of source code must retain the above copyright | |
| 19 * notice, this list of conditions and the following disclaimer. | |
| 20 * | |
| 21 * Redistributions in binary form must reproduce the above | |
| 22 * copyright notice, this list of conditions and the following | |
| 23 * disclaimer in the documentation and/or other materials provided | |
| 24 * with the distribution. | |
| 25 * | |
| 26 * Neither the name of the Cisco Systems, Inc. nor the names of its | |
| 27 * contributors may be used to endorse or promote products derived | |
| 28 * from this software without specific prior written permission. | |
| 29 * | |
| 30 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 31 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 32 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS | |
| 33 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE | |
| 34 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, | |
| 35 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES | |
| 36 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR | |
| 37 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
| 38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | |
| 39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED | |
| 41 * OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 42 * | |
| 43 */ | |
| 44 | |
| 45 | |
| 46 | |
| 47 /* | |
| 48 * EKT implementation strategy | |
| 49 * | |
| 50 * use stream_template approach | |
| 51 * | |
| 52 * in srtp_unprotect, when a new stream appears, check if template has | |
| 53 * EKT defined, and if it does, then apply EKT processing | |
| 54 * | |
| 55 * question: will we want to allow key-sharing templates in addition | |
| 56 * to EKT templates? could define a new ssrc_type_t that's associated | |
| 57 * with an EKT, e.g. ssrc_any_ekt. | |
| 58 * | |
| 59 * | |
| 60 */ | |
| 61 | |
| 62 #ifndef EKT_H | |
| 63 #define EKT_H | |
| 64 | |
| 65 #ifdef __cplusplus | |
| 66 extern "C" { | |
| 67 #endif | |
| 68 | |
| 69 #include "srtp_priv.h" | |
| 70 | |
| 71 #define EKT_CIPHER_DEFAULT 1 | |
| 72 #define EKT_CIPHER_AES_128_ECB 1 | |
| 73 #define EKT_CIPHER_AES_192_KEY_WRAP 2 | |
| 74 #define EKT_CIPHER_AES_256_KEY_WRAP 3 | |
| 75 | |
| 76 typedef uint16_t ekt_spi_t; | |
| 77 | |
| 78 | |
| 79 unsigned | |
| 80 ekt_octets_after_base_tag(ekt_stream_t ekt); | |
| 81 | |
| 82 /* | |
| 83 * an srtp_policy_t structure can contain a pointer to an | |
| 84 * ekt_policy_t structure | |
| 85 * | |
| 86 * this structure holds all of the high level EKT information, and it | |
| 87 * is passed into libsrtp to indicate what policy should be in effect | |
| 88 */ | |
| 89 | |
| 90 typedef struct ekt_policy_ctx_t { | |
| 91 ekt_spi_t spi; /* security parameter index */ | |
| 92 uint8_t ekt_cipher_type; | |
| 93 uint8_t *ekt_key; | |
| 94 struct ekt_policy_ctx_t *next_ekt_policy; | |
| 95 } ekt_policy_ctx_t; | |
| 96 | |
| 97 | |
| 98 /* | |
| 99 * an ekt_data_t structure holds the data corresponding to an ekt key, | |
| 100 * spi, and so on | |
| 101 */ | |
| 102 | |
| 103 typedef struct ekt_data_t { | |
| 104 ekt_spi_t spi; | |
| 105 uint8_t ekt_cipher_type; | |
| 106 aes_expanded_key_t ekt_enc_key; | |
| 107 aes_expanded_key_t ekt_dec_key; | |
| 108 struct ekt_data_t *next_ekt_data; | |
| 109 } ekt_data_t; | |
| 110 | |
| 111 /* | |
| 112 * an srtp_stream_ctx_t can contain an ekt_stream_ctx_t | |
| 113 * | |
| 114 * an ekt_stream_ctx_t structure holds all of the EKT information for | |
| 115 * a specific SRTP stream | |
| 116 */ | |
| 117 | |
| 118 typedef struct ekt_stream_ctx_t { | |
| 119 ekt_data_t *data; | |
| 120 uint16_t isn; /* initial sequence number */ | |
| 121 uint8_t encrypted_master_key[SRTP_MAX_KEY_LEN]; | |
| 122 } ekt_stream_ctx_t; | |
| 123 | |
| 124 | |
| 125 | |
| 126 err_status_t | |
| 127 ekt_alloc(ekt_stream_t *stream_data, ekt_policy_t policy); | |
| 128 | |
| 129 err_status_t | |
| 130 ekt_stream_init(ekt_stream_t e, | |
| 131 ekt_spi_t spi, | |
| 132 void *ekt_key, | |
| 133 unsigned ekt_cipher_type); | |
| 134 | |
| 135 err_status_t | |
| 136 ekt_stream_init_from_policy(ekt_stream_t e, ekt_policy_t p); | |
| 137 | |
| 138 | |
| 139 | |
| 140 err_status_t | |
| 141 srtp_stream_init_from_ekt(srtp_stream_t stream, | |
| 142 const void *srtcp_hdr, | |
| 143 unsigned pkt_octet_len); | |
| 144 | |
| 145 | |
| 146 void | |
| 147 ekt_write_data(ekt_stream_t ekt, | |
| 148 uint8_t *base_tag, | |
| 149 unsigned base_tag_len, | |
| 150 int *packet_len, | |
| 151 xtd_seq_num_t pkt_index); | |
| 152 | |
| 153 /* | |
| 154 * We handle EKT by performing some additional steps before | |
| 155 * authentication (copying the auth tag into a temporary location, | |
| 156 * zeroizing the "base tag" field in the packet) | |
| 157 * | |
| 158 * With EKT, the tag_len parameter is actually the base tag | |
| 159 * length | |
| 160 */ | |
| 161 | |
| 162 err_status_t | |
| 163 ekt_tag_verification_preproces(uint8_t *pkt_tag, | |
| 164 uint8_t *pkt_tag_copy, | |
| 165 unsigned tag_len); | |
| 166 | |
| 167 err_status_t | |
| 168 ekt_tag_verification_postproces(uint8_t *pkt_tag, | |
| 169 uint8_t *pkt_tag_copy, | |
| 170 unsigned tag_len); | |
| 171 | |
| 172 | |
| 173 /* | |
| 174 * @brief EKT pre-processing for srtcp tag generation | |
| 175 * | |
| 176 * This function does the pre-processing of the SRTCP authentication | |
| 177 * tag format. When EKT is used, it consists of writing the Encrypted | |
| 178 * Master Key, the SRTP ROC, the Initial Sequence Number, and SPI | |
| 179 * fields. The Base Authentication Tag field is set to the all-zero | |
| 180 * value | |
| 181 * | |
| 182 * When EKT is not used, this function is a no-op. | |
| 183 * | |
| 184 */ | |
| 185 | |
| 186 err_status_t | |
| 187 srtp_stream_srtcp_auth_tag_generation_preprocess(const srtp_stream_t *s, | |
| 188 uint8_t *pkt_tag, | |
| 189 unsigned pkt_octet_len); | |
| 190 | |
| 191 /* it's not clear that a tag_generation_postprocess function is needed */ | |
| 192 | |
| 193 err_status_t | |
| 194 srtcp_auth_tag_generation_postprocess(void); | |
| 195 | |
| 196 | |
| 197 #ifdef __cplusplus | |
| 198 } | |
| 199 #endif | |
| 200 | |
| 201 #endif /* EKT_H */ | |
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Chromium Code Reviews
Issue 2344973002:
Update libsrtp to version 2.0 (Closed)
