X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=src%2Futil%2Fcrypto_hkdf.c;h=f04d3e67505105f3febbc94aefc3067fe25f60a0;hb=03512957fb04969d08fb7eac0952a747aa9596ae;hp=96ff3804bfd8cabab35cadccdb03bb464b0d27c1;hpb=5695665772107f5c5b088f957a277efc9e3d089e;p=oweals%2Fgnunet.git

diff --git a/src/util/crypto_hkdf.c b/src/util/crypto_hkdf.c
index 96ff3804b..f04d3e675 100644
--- a/src/util/crypto_hkdf.c
+++ b/src/util/crypto_hkdf.c
@@ -26,14 +26,42 @@
  * @see http://www.rfc-editor.org/rfc/rfc5869.txt
  * @todo remove GNUNET references
  * @author Nils Durner
+ *
+ * The following list of people have reviewed this code and considered
+ * it correct on the date given (if you reviewed it, please
+ * have your name added to the list):
+ *
+ * - Christian Grothoff (08.10.2010)
+ * - Nathan Evans (08.10.2010)
+ * - Matthias Wachs (08.10.2010)
  */
 
-#include <gcrypt.h>
+#define LOG(kind,...) GNUNET_log_from (kind, "util-crypto-hkdf", __VA_ARGS__)
+
+/**
+ * Set this to 0 if you compile this code outside of GNUnet.
+ */
+#define GNUNET_BUILD 1
+
+/**
+ * Enable debugging.
+ */
+#define DEBUG_HKDF 0
+
 
+
+#if GNUNET_BUILD
 #include "platform.h"
 #include "gnunet_crypto_lib.h"
+#else
+#define GNUNET_NO 0
+#define GNUNET_YES 1
+#define GNUNET_SYSERR -1
+#include <stdlib.h>
+#endif
+
+#include <gcrypt.h>
 
-#define DEBUG_HKDF GNUNET_NO
 
 /**
  * @brief Compute the HMAC
@@ -46,9 +74,8 @@
  * @return HMAC, freed by caller via gcry_md_close/_reset
  */
 static const void *
-doHMAC (gcry_md_hd_t mac, 
-	const void *key, size_t key_len,
-	const void *buf, size_t buf_len)
+doHMAC (gcry_md_hd_t mac, const void *key, size_t key_len, const void *buf,
+        size_t buf_len)
 {
   gcry_md_setkey (mac, key, key_len);
   gcry_md_write (mac, buf, buf_len);
@@ -60,45 +87,39 @@ doHMAC (gcry_md_hd_t mac,
  * @brief Generate pseudo-random key
  * @param mac gcrypt HMAC handle
  * @param xts salt
- * @param xts_len length of the salt
+ * @param xts_len length of the @a xts salt
  * @param skm source key material
- * @param skm_len length of skm
+ * @param skm_len length of @a skm
  * @param prk result buffer (allocated by caller; at least gcry_md_dlen() bytes)
- * @return GNUNET_YES on success
+ * @return #GNUNET_YES on success
  */
 static int
-getPRK (gcry_md_hd_t mac, 
-	const void *xts, size_t xts_len,
-	const void *skm, size_t skm_len,
-	void *prk)
+getPRK (gcry_md_hd_t mac, const void *xts, size_t xts_len, const void *skm,
+        size_t skm_len, void *prk)
 {
   const void *ret;
 
   ret = doHMAC (mac, xts, xts_len, skm, skm_len);
   if (ret == NULL)
     return GNUNET_SYSERR;
-  memcpy (prk,
-	  ret,
-	  gcry_md_get_algo_dlen (gcry_md_get_algo (mac)));
+  GNUNET_memcpy (prk, ret, gcry_md_get_algo_dlen (gcry_md_get_algo (mac)));
 
   return GNUNET_YES;
 }
 
 
 #if DEBUG_HKDF
-static void 
-dump(const char *src, 
-     const void *p, 
-     unsigned int l)
+static void
+dump (const char *src, const void *p, unsigned int l)
 {
   unsigned int i;
 
-  printf("\n%s: ", src);
+  printf ("\n%s: ", src);
   for (i = 0; i < l; i++)
-    {
-      printf("%2x", (int) ((const unsigned char *) p)[i]);
-    }
-  printf("\n");
+  {
+    printf ("%2x", (int) ((const unsigned char *) p)[i]);
+  }
+  printf ("\n");
 }
 #endif
 
@@ -110,58 +131,54 @@ dump(const char *src,
  * @param xtr_algo hash algorithm for the extraction phase, GCRY_MD_...
  * @param prf_algo hash algorithm for the expansion phase, GCRY_MD_...
  * @param xts salt
- * @param xts_len length of xts
+ * @param xts_len length of @a xts
  * @param skm source key material
- * @param skm_len length of skm
+ * @param skm_len length of @a skm
  * @param argp va_list of void * & size_t pairs for context chunks
- * @return GNUNET_YES on success
+ * @return #GNUNET_YES on success
  */
 int
-GNUNET_CRYPTO_hkdf_v (void *result, size_t out_len,
-		      int xtr_algo, int prf_algo, 
-		      const void *xts, size_t xts_len,
-		      const void *skm, size_t skm_len,
-		      va_list argp)
+GNUNET_CRYPTO_hkdf_v (void *result, size_t out_len, int xtr_algo, int prf_algo,
+                      const void *xts, size_t xts_len, const void *skm,
+                      size_t skm_len, va_list argp)
 {
+  gcry_md_hd_t xtr;
+  gcry_md_hd_t prf;
   const void *hc;
-  unsigned long i, t, d;
+  unsigned long i;
+  unsigned long t;
+  unsigned long d;
   unsigned int k = gcry_md_get_algo_dlen (prf_algo);
   unsigned int xtr_len = gcry_md_get_algo_dlen (xtr_algo);
   char prk[xtr_len];
   int ret;
-  gcry_md_hd_t xtr, prf;
   size_t ctx_len;
   va_list args;
 
-  if (k == 0)
-    return GNUNET_SYSERR;
-
-  // FIXME: what is the check for?
-  if (out_len > (2 ^ 32 * k))
+  if (0 == k)
     return GNUNET_SYSERR;
-
-  if (gcry_md_open(&xtr, xtr_algo, GCRY_MD_FLAG_HMAC) != GPG_ERR_NO_ERROR)
+  if (GPG_ERR_NO_ERROR !=
+      gcry_md_open (&xtr, xtr_algo, GCRY_MD_FLAG_HMAC))
     return GNUNET_SYSERR;
-
-  if (gcry_md_open(&prf, prf_algo, GCRY_MD_FLAG_HMAC) != GPG_ERR_NO_ERROR)
+  if (GPG_ERR_NO_ERROR !=
+      gcry_md_open (&prf, prf_algo, GCRY_MD_FLAG_HMAC))
   {
     gcry_md_close (xtr);
     return GNUNET_SYSERR;
   }
-
   va_copy (args, argp);
 
   ctx_len = 0;
   while (NULL != va_arg (args, void *))
-    ctx_len += va_arg (args, size_t);
-  va_end(args);
+         ctx_len += va_arg (args, size_t);
+
+  va_end (args);
 
   memset (result, 0, out_len);
-  if (getPRK (xtr, xts, xts_len, skm, skm_len, prk)
-      != GNUNET_YES)
+  if (getPRK (xtr, xts, xts_len, skm, skm_len, prk) != GNUNET_YES)
     goto hkdf_error;
 #if DEBUG_HKDF
-  dump("PRK", prk, xtr_len);
+  dump ("PRK", prk, xtr_len);
 #endif
 
   t = out_len / k;
@@ -169,63 +186,64 @@ GNUNET_CRYPTO_hkdf_v (void *result, size_t out_len,
 
   /* K(1) */
   {
-  size_t plain_len = k + ctx_len + 1;
-  char plain[plain_len];
-      const void *ctx;
-      char *dst;
-
-      dst = plain + k;
-      va_copy (args, argp);
-      while ((ctx = va_arg (args, void *)))
-        {
-          size_t len;
-
-          len = va_arg (args, size_t);
-          memcpy (dst, ctx, len);
-          dst += len;
-        }
-      va_end (args);
-
-  if (t > 0)
+    size_t plain_len = k + ctx_len + 1;
+    char plain[plain_len];
+    const void *ctx;
+    char *dst;
+
+    dst = plain + k;
+    va_copy (args, argp);
+    while ((ctx = va_arg (args, void *)))
+    {
+      size_t len;
+
+      len = va_arg (args, size_t);
+      GNUNET_memcpy (dst, ctx, len);
+      dst += len;
+    }
+    va_end (args);
+
+    if (t > 0)
     {
       memset (plain + k + ctx_len, 1, 1);
 #if DEBUG_HKDF
-      dump("K(1)", plain, plain_len);
+      dump ("K(1)", plain, plain_len);
 #endif
-      hc = doHMAC (prf, 
-		   prk,
-		   xtr_len, &plain[k], ctx_len + 1);
+      hc = doHMAC (prf, prk, xtr_len, &plain[k], ctx_len + 1);
       if (hc == NULL)
         goto hkdf_error;
-      memcpy (result, hc, k);
+      GNUNET_memcpy (result, hc, k);
       result += k;
     }
 
-  /* K(i+1) */
-  for (i = 1; i < t; i++)
+    /* K(i+1) */
+    for (i = 1; i < t; i++)
     {
-      memcpy (plain, result - k, k);
+      GNUNET_memcpy (plain, result - k, k);
       memset (plain + k + ctx_len, i + 1, 1);
       gcry_md_reset (prf);
 #if DEBUG_HKDF
-      dump("K(i+1)", plain, plain_len);
+      dump ("K(i+1)", plain, plain_len);
 #endif
       hc = doHMAC (prf, prk, xtr_len, plain, plain_len);
       if (hc == NULL)
         goto hkdf_error;
-      memcpy (result, hc, k);
+      GNUNET_memcpy (result, hc, k);
       result += k;
     }
 
-  /* K(t):d */
-  if (d > 0)
+    /* K(t):d */
+    if (d > 0)
     {
       if (t > 0)
-        memcpy (plain, result - k, k);
-      memset (plain + k + ctx_len, i + 1, 1);
+      {
+        GNUNET_memcpy (plain, result - k, k);
+        i++;
+      }
+      memset (plain + k + ctx_len, i, 1);
       gcry_md_reset (prf);
 #if DEBUG_HKDF
-      dump("K(t):d", plain, plain_len);
+      dump ("K(t):d", plain, plain_len);
 #endif
       if (t > 0)
         hc = doHMAC (prf, prk, xtr_len, plain, plain_len);
@@ -233,21 +251,20 @@ GNUNET_CRYPTO_hkdf_v (void *result, size_t out_len,
         hc = doHMAC (prf, prk, xtr_len, plain + k, plain_len - k);
       if (hc == NULL)
         goto hkdf_error;
-      memcpy (result, hc, d);
+      GNUNET_memcpy (result, hc, d);
     }
 #if DEBUG_HKDF
-  dump("result", result - k, out_len);
+    dump ("result", result - k, out_len);
 #endif
 
-  ret = GNUNET_YES;
-  goto hkdf_ok;
+    ret = GNUNET_YES;
+    goto hkdf_ok;
   }
 hkdf_error:
   ret = GNUNET_SYSERR;
 hkdf_ok:
-  gcry_md_close (prf);
   gcry_md_close (xtr);
-
+  gcry_md_close (prf);
   return ret;
 }
 
@@ -259,27 +276,24 @@ hkdf_ok:
  * @param xtr_algo hash algorithm for the extraction phase, GCRY_MD_...
  * @param prf_algo hash algorithm for the expansion phase, GCRY_MD_...
  * @param xts salt
- * @param xts_len length of xts
+ * @param xts_len length of @a xts
  * @param skm source key material
- * @param skm_len length of skm
- * @param ctx context info
- * @param ctx_len length of ctx
- * @return GNUNET_YES on success
+ * @param skm_len length of @a skm
+ * @return #GNUNET_YES on success
  */
 int
-GNUNET_CRYPTO_hkdf (void *result, size_t out_len,
-		    int xtr_algo, int prf_algo, 
-		    const void *xts, size_t xts_len,
-		    const void *skm, size_t skm_len, 
-		    ...)
+GNUNET_CRYPTO_hkdf (void *result, size_t out_len, int xtr_algo, int prf_algo,
+                    const void *xts, size_t xts_len, const void *skm,
+                    size_t skm_len, ...)
 {
   va_list argp;
   int ret;
 
-  va_start(argp, skm_len);
-  ret = GNUNET_CRYPTO_hkdf_v (result, out_len, xtr_algo, prf_algo, xts,
-      xts_len, skm, skm_len, argp);
-  va_end(argp);
+  va_start (argp, skm_len);
+  ret =
+      GNUNET_CRYPTO_hkdf_v (result, out_len, xtr_algo, prf_algo, xts, xts_len,
+                            skm, skm_len, argp);
+  va_end (argp);
 
   return ret;
 }