Cedric Roux
8fa5602278
- Fix some debug formats git-svn-id: http://svn.eurecom.fr/openair4G/trunk@4187 818b1a75-f10b-46b9-bf7c-635c3b92a50f
111 lines
2.8 KiB
C
111 lines
2.8 KiB
C
#include <stdint.h>
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#include <nettle/hmac.h>
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#include "osa_defs.h"
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#include "osa_internal.h"
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#include "UTIL/LOG/log.h"
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static inline
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void kdf(const uint8_t *s, const uint32_t s_length, const uint8_t *key,
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const uint32_t key_length, uint8_t **out, uint32_t out_length)
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{
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struct hmac_sha256_ctx ctx;
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uint8_t *buffer;
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buffer = malloc(sizeof(uint8_t) * out_length);
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hmac_sha256_set_key(&ctx, key_length, key);
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hmac_sha256_update(&ctx, s_length, s);
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hmac_sha256_digest(&ctx, out_length, buffer);
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*out = buffer;
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}
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/*!
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* @brief Derive the keys from key and perform truncate on the generated key to
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* reduce his size to 128 bits. Definition of the derivation function can
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* be found in 3GPP TS.33401 #A.7
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* @param[in] alg_type Algorithm distinguisher
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* @param[in] alg_id Algorithm identifier.
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* Possible values are:
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* - 0 for EIA0 algorithm (Null Integrity Protection algorithm)
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* - 1 for 128-EIA1 SNOW 3G
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* - 2 for 128-EIA2 AES
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* @param[in] key The top key used to derive other subkeys
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* @param[out] out Pointer to reference where output of KDF will be stored.
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* NOTE: knas is dynamically allocated by the KDF function
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*/
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int derive_key(algorithm_type_dist_t alg_type, uint8_t alg_id,
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const uint8_t key[32], uint8_t **out)
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{
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uint8_t string[7];
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/* FC */
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string[0] = FC_ALG_KEY_DER;
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/* P0 = algorithm type distinguisher */
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string[1] = (uint8_t)(alg_type & 0xFF);
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/* L0 = length(P0) = 1 */
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string[2] = 0x00;
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string[3] = 0x01;
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/* P1 */
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string[4] = alg_id;
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/* L1 = length(P1) = 1 */
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string[5] = 0x00;
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string[6] = 0x01;
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#if defined(SECU_DEBUG)
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{
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int i;
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char payload[6 * sizeof(string) + 1];
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int index = 0;
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for (i = 0; i < sizeof(string); i++)
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index += sprintf(&payload[index], "0x%02x ", string[i]);
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LOG_D(OSA, "Key deriver input string: %s\n", payload);
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}
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#endif
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kdf(string, 7, key, 32, out, 32);
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return 0;
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}
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int derive_keNB(const uint8_t key[32], const uint32_t nas_count, uint8_t **keNB)
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{
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uint8_t string[7];
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/* FC */
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string[0] = FC_KENB;
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/* P0 = Uplink NAS count */
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string[1] = (nas_count & 0xff000000) >> 24;
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string[2] = (nas_count & 0x00ff0000) >> 16;
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string[3] = (nas_count & 0x0000ff00) >> 8;
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string[4] = (nas_count & 0x000000ff);
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/* Length of NAS count */
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string[5] = 0x00;
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string[6] = 0x04;
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#if defined(SECU_DEBUG)
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{
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int i;
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char payload[6 * sizeof(string) + 1];
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int index = 0;
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for (i = 0; i < sizeof(string); i++)
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index += sprintf(&payload[index], "0x%02x ", string[i]);
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LOG_D(OSA, "KeNB deriver input string: %s\n", payload);
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}
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#endif
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kdf(string, 7, key, 32, keNB, 32);
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return 0;
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}
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