diff options
Diffstat (limited to 'src/crypto/sha1-prf.c')
-rw-r--r-- | src/crypto/sha1-prf.c | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/src/crypto/sha1-prf.c b/src/crypto/sha1-prf.c new file mode 100644 index 00000000..90b9e74b --- /dev/null +++ b/src/crypto/sha1-prf.c @@ -0,0 +1,66 @@ +/* + * SHA1-based PRF + * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi> + * + * This software may be distributed under the terms of the BSD license. + * See README for more details. + */ + +#include "includes.h" + +#include "common.h" +#include "sha1.h" +#include "crypto.h" + + +/** + * sha1_prf - SHA1-based Pseudo-Random Function (PRF) (IEEE 802.11i, 8.5.1.1) + * @key: Key for PRF + * @key_len: Length of the key in bytes + * @label: A unique label for each purpose of the PRF + * @data: Extra data to bind into the key + * @data_len: Length of the data + * @buf: Buffer for the generated pseudo-random key + * @buf_len: Number of bytes of key to generate + * Returns: 0 on success, -1 of failure + * + * This function is used to derive new, cryptographically separate keys from a + * given key (e.g., PMK in IEEE 802.11i). + */ +int sha1_prf(const u8 *key, size_t key_len, const char *label, + const u8 *data, size_t data_len, u8 *buf, size_t buf_len) +{ + u8 counter = 0; + size_t pos, plen; + u8 hash[SHA1_MAC_LEN]; + size_t label_len = os_strlen(label) + 1; + const unsigned char *addr[3]; + size_t len[3]; + + addr[0] = (u8 *) label; + len[0] = label_len; + addr[1] = data; + len[1] = data_len; + addr[2] = &counter; + len[2] = 1; + + pos = 0; + while (pos < buf_len) { + plen = buf_len - pos; + if (plen >= SHA1_MAC_LEN) { + if (hmac_sha1_vector(key, key_len, 3, addr, len, + &buf[pos])) + return -1; + pos += SHA1_MAC_LEN; + } else { + if (hmac_sha1_vector(key, key_len, 3, addr, len, + hash)) + return -1; + os_memcpy(&buf[pos], hash, plen); + break; + } + counter++; + } + + return 0; +} |