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authorJouni Malinen <j@w1.fi>2019-08-16 18:15:32 (GMT)
committerJouni Malinen <j@w1.fi>2019-08-16 18:16:37 (GMT)
commit52069c7eff4822650ed98358719ccebd85d53163 (patch)
tree4254bbad9701961b0714b8dc23dd07e3aaa8821d /src/crypto
parent263c0cbdc05bfd6b316dc59ddbd1024e3acdb402 (diff)
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Add TLS-PRF using HMAC with P_SHA384 for TEAP
This version of TLS PRF is needed when using TEAP with TLS ciphersuites that are defined to use SHA384 instead of SHA256. Signed-off-by: Jouni Malinen <j@w1.fi>
Diffstat (limited to 'src/crypto')
-rw-r--r--src/crypto/sha384-tlsprf.c71
-rw-r--r--src/crypto/sha384.h3
2 files changed, 74 insertions, 0 deletions
diff --git a/src/crypto/sha384-tlsprf.c b/src/crypto/sha384-tlsprf.c
new file mode 100644
index 0000000..9ff96ac
--- /dev/null
+++ b/src/crypto/sha384-tlsprf.c
@@ -0,0 +1,71 @@
+/*
+ * TLS PRF P_SHA384
+ * Copyright (c) 2011-2019, 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 "sha384.h"
+
+
+/**
+ * tls_prf_sha384 - Pseudo-Random Function for TLS v1.2 (P_SHA384, RFC 5246)
+ * @secret: Key for PRF
+ * @secret_len: Length of the key in bytes
+ * @label: A unique label for each purpose of the PRF
+ * @seed: Seed value to bind into the key
+ * @seed_len: Length of the seed
+ * @out: Buffer for the generated pseudo-random key
+ * @outlen: Number of bytes of key to generate
+ * Returns: 0 on success, -1 on failure.
+ *
+ * This function is used to derive new, cryptographically separate keys from a
+ * given key in TLS. This PRF is defined in RFC 5246, Chapter 5.
+ */
+int tls_prf_sha384(const u8 *secret, size_t secret_len, const char *label,
+ const u8 *seed, size_t seed_len, u8 *out, size_t outlen)
+{
+ size_t clen;
+ u8 A[SHA384_MAC_LEN];
+ u8 P[SHA384_MAC_LEN];
+ size_t pos;
+ const unsigned char *addr[3];
+ size_t len[3];
+
+ addr[0] = A;
+ len[0] = SHA384_MAC_LEN;
+ addr[1] = (unsigned char *) label;
+ len[1] = os_strlen(label);
+ addr[2] = seed;
+ len[2] = seed_len;
+
+ /*
+ * RFC 5246, Chapter 5
+ * A(0) = seed, A(i) = HMAC(secret, A(i-1))
+ * P_hash = HMAC(secret, A(1) + seed) + HMAC(secret, A(2) + seed) + ..
+ * PRF(secret, label, seed) = P_SHA384(secret, label + seed)
+ */
+
+ if (hmac_sha384_vector(secret, secret_len, 2, &addr[1], &len[1], A) < 0)
+ return -1;
+
+ pos = 0;
+ while (pos < outlen) {
+ if (hmac_sha384_vector(secret, secret_len, 3, addr, len, P) <
+ 0 ||
+ hmac_sha384(secret, secret_len, A, SHA384_MAC_LEN, A) < 0)
+ return -1;
+
+ clen = outlen - pos;
+ if (clen > SHA384_MAC_LEN)
+ clen = SHA384_MAC_LEN;
+ os_memcpy(out + pos, P, clen);
+ pos += clen;
+ }
+
+ return 0;
+}
diff --git a/src/crypto/sha384.h b/src/crypto/sha384.h
index 2241425..d946907 100644
--- a/src/crypto/sha384.h
+++ b/src/crypto/sha384.h
@@ -20,6 +20,9 @@ int sha384_prf(const u8 *key, size_t key_len, const char *label,
int sha384_prf_bits(const u8 *key, size_t key_len, const char *label,
const u8 *data, size_t data_len, u8 *buf,
size_t buf_len_bits);
+int tls_prf_sha384(const u8 *secret, size_t secret_len,
+ const char *label, const u8 *seed, size_t seed_len,
+ u8 *out, size_t outlen);
int hmac_sha384_kdf(const u8 *secret, size_t secret_len,
const char *label, const u8 *seed, size_t seed_len,
u8 *out, size_t outlen);