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iwd
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crypto: Add support for PRF+ SHA1 

The PRF+ algorithm is based Internet Key Exchange (IKEv2) Protocol:
	https://www.ietf.org/rfc/rfc4306.txt
This commit is contained in:
Tim Kourt 2019-12-05 13:13:53 -08:00 committed by Denis Kenzior
parent 24b6a95366
commit 1b483c3963
2 changed files with 67 additions and 0 deletions
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64
src/crypto.c
View File

@ -581,6 +581,70 @@ bool prf_sha1(const void *key, size_t key_len,
return true;
}
bool prf_plus_sha1(const void *key, size_t key_len,
const void *label, size_t label_len,
const void *seed, size_t seed_len,
void *output, size_t size)
{
/*
* PRF+ (K, S, LEN) = T1 | T2 | T3 | T4 | ... where:
*
* T1 = HMAC-SHA1 (K, S | LEN | 0x01 | 0x00 | 0x00)
*
* T2 = HMAC-SHA1 (K, T1 | S | LEN | 0x02 | 0x00 | 0x00)
*
* T3 = HMAC-SHA1 (K, T2 | S | LEN | 0x03 | 0x00 | 0x00)
*
* T4 = HMAC-SHA1 (K, T3 | S | LEN | 0x04 | 0x00 | 0x00)
*
* ...
*/
static const uint8_t SHA1_MAC_LEN = 20;
static const uint8_t nil_bytes[2] = { 0, 0 };
struct l_checksum *hmac;
uint8_t t[SHA1_MAC_LEN];
uint8_t counter;
struct iovec iov[5] = {
[0] = { .iov_base = (void *) t, .iov_len = 0 },
[1] = { .iov_base = (void *) label, .iov_len = label_len },
[2] = { .iov_base = (void *) seed, .iov_len = seed_len },
[3] = { .iov_base = &counter, .iov_len = 1 },
[4] = { .iov_base = (void *) nil_bytes, .iov_len = 2 },
};
hmac = l_checksum_new_hmac(L_CHECKSUM_SHA1, key, key_len);
if (!hmac)
return false;
/* PRF processes in 160-bit chunks (20 bytes) */
for (counter = 1;; counter++) {
size_t len;
if (size > SHA1_MAC_LEN)
len = SHA1_MAC_LEN;
else
len = size;
l_checksum_updatev(hmac, iov, 5);
l_checksum_get_digest(hmac, t, len);
memcpy(output, t, len);
size -= len;
if (!size)
break;
output += len;
iov[0].iov_len = len;
}
l_checksum_free(hmac);
return true;
}
/* Defined in 802.11-2012, Section 11.6.1.7.2 Key derivation function (KDF) */
bool kdf_sha256(const void *key, size_t key_len,
const void *prefix, size_t prefix_len,

3
src/crypto.h
View File

@ -106,6 +106,9 @@ bool kdf_sha384(const void *key, size_t key_len,
bool prf_sha1(const void *key, size_t key_len,
const void *prefix, size_t prefix_len,
const void *data, size_t data_len, void *output, size_t size);
bool prf_plus_sha1(const void *key, size_t key_len,
const void *prefix, size_t prefix_len,
const void *data, size_t data_len, void *output, size_t size);
bool hkdf_extract(enum l_checksum_type type, const uint8_t *key, size_t key_len,
uint8_t num_args, uint8_t *out, ...);