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 0000000..90b9e74
--- /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;
+}