X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=src%2Futil%2Fcrypto_hkdf.c;h=494f3d0ab9efcda76f4fc560bfb3ccbecefde1de;hb=bb83cd2d04ff5a3f7a8d05fc9a724b0246e958b6;hp=00750554f84b467d947be770c2929034fa0f1640;hpb=0f8fe7f9eedfe9f70333b9bc7105cbc096af5f05;p=oweals%2Fgnunet.git diff --git a/src/util/crypto_hkdf.c b/src/util/crypto_hkdf.c index 00750554f..494f3d0ab 100644 --- a/src/util/crypto_hkdf.c +++ b/src/util/crypto_hkdf.c @@ -24,18 +24,45 @@ * @file src/util/crypto_hkdf.c * @brief Hash-based KDF as defined in RFC 5869 * @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 +/** + * 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 +#endif + +#include -#define DEBUG_HKDF GNUNET_NO /** * @brief Compute the HMAC + * @todo use chunked buffers * @param mac gcrypt MAC handle * @param key HMAC key * @param key_len length of key @@ -43,14 +70,15 @@ * @param buf_len length of buf * @return HMAC, freed by caller via gcry_md_close/_reset */ -static void * -doHMAC (gcry_md_hd_t mac, const void *key, const size_t key_len, - const void *buf, const size_t buf_len) +static const void * +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); - return (void *) gcry_md_read (mac, 0); + return (const void *) gcry_md_read (mac, 0); } /** @@ -64,33 +92,42 @@ doHMAC (gcry_md_hd_t mac, const void *key, const size_t key_len, * @return GNUNET_YES on success */ static int -getPRK (gcry_md_hd_t mac, const void *xts, const unsigned long long xts_len, - const void *skm, const unsigned long long 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) { - void *ret; + 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))); + memcpy (prk, + ret, + gcry_md_get_algo_dlen (gcry_md_get_algo (mac))); return GNUNET_YES; } + #if DEBUG_HKDF -static void dump(char *src, void *p, unsigned int l) +static void +dump(const char *src, + const void *p, + unsigned int l) { unsigned int i; printf("\n%s: ", src); for (i = 0; i < l; i++) { - printf("%2x", (int) ((unsigned char *) p)[i]); + printf("%2x", (int) ((const unsigned char *) p)[i]); } printf("\n"); } #endif + /** * @brief Derive key * @param result buffer for the derived key, allocated by caller @@ -105,37 +142,42 @@ static void dump(char *src, void *p, unsigned int l) * @return GNUNET_YES on success */ int -GNUNET_CRYPTO_hkdf_v (void *result, const unsigned long long out_len, - int xtr_algo, int prf_algo, const void *xts, const size_t xts_len, - const void *skm, const 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) { - void *prk, *hc, *plain; - unsigned long long plain_len; + const void *hc; unsigned long i, t, d; - unsigned int k, xtr_len; + 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; - prk = plain = NULL; - xtr_len = gcry_md_get_algo_dlen (xtr_algo); - k = gcry_md_get_algo_dlen (prf_algo); - gcry_md_open(&xtr, xtr_algo, GCRY_MD_FLAG_HMAC); - gcry_md_open(&prf, prf_algo, GCRY_MD_FLAG_HMAC); + if (k == 0) + return GNUNET_SYSERR; + + if (gcry_md_open(&xtr, xtr_algo, GCRY_MD_FLAG_HMAC) != GPG_ERR_NO_ERROR) + return GNUNET_SYSERR; - if (out_len > (2 ^ 32 * k) || !xtr_algo || !prf_algo) + if (gcry_md_open(&prf, prf_algo, GCRY_MD_FLAG_HMAC) != GPG_ERR_NO_ERROR) + { + gcry_md_close (xtr); return GNUNET_SYSERR; + } va_copy (args, argp); - for (ctx_len = 0; va_arg (args, void *);) + + ctx_len = 0; + while (NULL != va_arg (args, void *)) ctx_len += va_arg (args, size_t); va_end(args); - prk = GNUNET_malloc (xtr_len); - memset (result, 0, out_len); - gcry_md_reset (xtr); if (getPRK (xtr, xts, xts_len, skm, skm_len, prk) != GNUNET_YES) goto hkdf_error; @@ -147,13 +189,13 @@ GNUNET_CRYPTO_hkdf_v (void *result, const unsigned long long out_len, d = out_len % k; /* K(1) */ - plain_len = k + ctx_len + 1; - plain = GNUNET_malloc (plain_len); - if (t > 0) - { - void *ctx, *dst; + { + size_t plain_len = k + ctx_len + 1; + char plain[plain_len]; + const void *ctx; + char *dst; - dst = plain; + dst = plain + k; va_copy (args, argp); while ((ctx = va_arg (args, void *))) { @@ -165,35 +207,21 @@ GNUNET_CRYPTO_hkdf_v (void *result, const unsigned long long out_len, } va_end (args); - memset (dst, 1, 1); - gcry_md_reset (prf); + if (t > 0) + { + memset (plain + k + ctx_len, 1, 1); #if DEBUG_HKDF dump("K(1)", plain, plain_len); #endif - hc = doHMAC (prf, prk, xtr_len, plain, ctx_len + 1); + hc = doHMAC (prf, + prk, + xtr_len, &plain[k], ctx_len + 1); if (hc == NULL) goto hkdf_error; memcpy (result, hc, k); result += k; } - if (t > 1 || d > 0) - { - void *ctx, *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); - } - /* K(i+1) */ for (i = 1; i < t; i++) { @@ -214,13 +242,19 @@ GNUNET_CRYPTO_hkdf_v (void *result, const unsigned long long out_len, if (d > 0) { if (t > 0) - memcpy (plain, result - k, k); - memset (plain + k + ctx_len, i + 1, 1); + { + 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); #endif - hc = doHMAC (prf, prk, xtr_len, plain, plain_len); + if (t > 0) + hc = doHMAC (prf, prk, xtr_len, plain, plain_len); + else + hc = doHMAC (prf, prk, xtr_len, plain + k, plain_len - k); if (hc == NULL) goto hkdf_error; memcpy (result, hc, d); @@ -231,18 +265,17 @@ GNUNET_CRYPTO_hkdf_v (void *result, const unsigned long long out_len, ret = GNUNET_YES; goto hkdf_ok; - + } hkdf_error: ret = GNUNET_SYSERR; hkdf_ok: - GNUNET_free (prk); - GNUNET_free_non_null (plain); gcry_md_close (prf); gcry_md_close (xtr); return ret; } + /** * @brief Derive key * @param result buffer for the derived key, allocated by caller @@ -253,14 +286,14 @@ hkdf_ok: * @param xts_len length of 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 */ int -GNUNET_CRYPTO_hkdf (void *result, const unsigned long long out_len, - int xtr_algo, int prf_algo, const void *xts, const size_t xts_len, - const void *skm, const 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;