From 6882ac57ec9bfc945d29304df11fe60dc70b8d5a Mon Sep 17 00:00:00 2001
From: Michael Rash <mbr@cipherdyne.org>
Date: Sun, 10 Mar 2013 14:56:39 -0400
Subject: [PATCH] add HMAC-SHA1 support

---
 lib/fko_hmac.c |  6 +++-
 lib/hmac.c     | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/hmac.h     |  2 ++
 lib/sha1.h     |  2 ++
 4 files changed, 83 insertions(+), 1 deletion(-)

diff --git a/lib/fko_hmac.c b/lib/fko_hmac.c
index a698c411..59ce4363 100644
--- a/lib/fko_hmac.c
+++ b/lib/fko_hmac.c
@@ -196,7 +196,11 @@ int fko_calculate_hmac(fko_ctx_t ctx,
     }
     else if(ctx->hmac_type == FKO_HMAC_SHA1)
     {
-        return(FKO_ERROR_CTX_NOT_INITIALIZED);
+        hmac_sha1(ctx->encrypted_msg,
+            ctx->encrypted_msg_len, hmac, hmac_key, hmac_key_len);
+
+        hmac_digest_len     = SHA1_DIGEST_LEN;
+        hmac_digest_str_len = SHA1_DIGEST_STR_LEN;
     }
     else if(ctx->hmac_type == FKO_HMAC_SHA256)
     {
diff --git a/lib/hmac.c b/lib/hmac.c
index 5857b116..05312b54 100644
--- a/lib/hmac.c
+++ b/lib/hmac.c
@@ -31,6 +31,14 @@
 
 #include "hmac.h"
 
+typedef struct {
+    SHA1_INFO ctx_inside;
+    SHA1_INFO ctx_outside;
+
+    unsigned char block_inner_pad[SHA1_BLOCK_LEN];
+    unsigned char block_outer_pad[SHA1_BLOCK_LEN];
+} hmac_sha1_ctx;
+
 typedef struct {
     SHA256_CTX ctx_inside;
     SHA256_CTX ctx_outside;
@@ -55,6 +63,72 @@ typedef struct {
     unsigned char block_outer_pad[SHA512_BLOCK_LEN];
 } hmac_sha512_ctx;
 
+/* Begin SHA1 HMAC functions
+*/
+static void
+hmac_sha1_init(hmac_sha1_ctx *ctx, const char *key, const int key_len)
+{
+    int i = 0;
+
+    for (i=0; i < key_len; i++) {
+        ctx->block_inner_pad[i] = key[i] ^ 0x36;
+        ctx->block_outer_pad[i] = key[i] ^ 0x5c;
+    }
+
+    if(i < SHA1_BLOCK_LEN)
+    {
+        while(i < SHA1_BLOCK_LEN)
+        {
+            ctx->block_inner_pad[i] = 0x36;
+            ctx->block_outer_pad[i] = 0x5c;
+            i++;
+        }
+    }
+
+    sha1_init(&ctx->ctx_inside);
+    sha1_update(&ctx->ctx_inside, ctx->block_inner_pad, SHA1_BLOCK_LEN);
+
+    sha1_init(&ctx->ctx_outside);
+    sha1_update(&ctx->ctx_outside, ctx->block_outer_pad, SHA1_BLOCK_LEN);
+
+    return;
+}
+
+static void
+hmac_sha1_update(hmac_sha1_ctx *ctx, const char *msg,
+    unsigned int msg_len)
+{
+    sha1_update(&ctx->ctx_inside, (unsigned char *)msg, msg_len);
+    return;
+}
+
+static void
+hmac_sha1_final(hmac_sha1_ctx *ctx, unsigned char *hmac)
+{
+    unsigned char digest_inside[SHA1_DIGEST_LEN];
+
+    sha1_final(digest_inside, &ctx->ctx_inside);
+    sha1_update(&ctx->ctx_outside, digest_inside, SHA1_DIGEST_LEN);
+    sha1_final(hmac, &ctx->ctx_outside);
+
+    return;
+}
+
+void
+hmac_sha1(const char *msg, const unsigned int msg_len,
+    unsigned char *hmac, const char *hmac_key, const int hmac_key_len)
+{
+    hmac_sha1_ctx ctx;
+
+    memset(&ctx, 0, sizeof(&ctx));
+
+    hmac_sha1_init(&ctx, hmac_key, hmac_key_len);
+    hmac_sha1_update(&ctx, msg, msg_len);
+    hmac_sha1_final(&ctx, hmac);
+
+    return;
+}
+
 /* Begin SHA256 HMAC functions
 */
 static void
diff --git a/lib/hmac.h b/lib/hmac.h
index b853a4f1..04018fdb 100644
--- a/lib/hmac.h
+++ b/lib/hmac.h
@@ -33,6 +33,8 @@
 
 #include "digest.h"
 
+void hmac_sha1(const char *msg, const unsigned int msg_len,
+        unsigned char *hmac, const char *hmac_key, const int hmac_key_len);
 void hmac_sha256(const char *msg, const unsigned int msg_len,
         unsigned char *hmac, const char *hmac_key, const int hmac_key_len);
 void hmac_sha384(const char *msg, const unsigned int msg_len,
diff --git a/lib/sha1.h b/lib/sha1.h
index dfa1e887..5edcc52e 100644
--- a/lib/sha1.h
+++ b/lib/sha1.h
@@ -45,7 +45,9 @@
 #endif
 
 #define SHA1_BLOCKSIZE      64
+#define SHA1_BLOCK_LEN      SHA1_BLOCKSIZE
 #define SHA1_DIGEST_LEN     20
+#define SHA1_DIGEST_STR_LEN (SHA1_DIGEST_LEN * 2 + 1)
 #define SHA1_B64_LEN        27
 
 typedef struct {