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crypto: remove unnecessary usage of malloc()/dtls_hmac_new()
This has the following optimization potentials which are also applied. - crypto: only one HMAC context is required - crypto: integrate last iteration into loop - hmac: remove dtls_hmac_new()/_free()/_storage_init() as dtls_hmac_new() now only is used in tests Co-Authored-By: Leandro Lanzieri <leandro.lanzieri@haw-hamburg.de> Signed-off-by: Martine Lenders <m.lenders@fu-berlin.de>
This commit is contained in:
Martine S. Lenders
Martine Lenders
parent
fbf2bd89ff
commit
47289eec09
66
crypto.c
66
crypto.c
@ -207,7 +207,7 @@ dtls_p_hash(dtls_hashfunc_t h,
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const unsigned char *random1, size_t random1len,
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const unsigned char *random2, size_t random2len,
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unsigned char *buf, size_t buflen) {
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dtls_hmac_context_t *hmac_a, *hmac_p;
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dtls_hmac_context_t hmac;
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unsigned char A[DTLS_HMAC_DIGEST_SIZE];
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unsigned char tmp[DTLS_HMAC_DIGEST_SIZE];
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@ -215,54 +215,44 @@ dtls_p_hash(dtls_hashfunc_t h,
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size_t len = 0; /* result length */
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(void)h;
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hmac_a = dtls_hmac_new(key, keylen);
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if (!hmac_a)
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return 0;
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dtls_hmac_init(&hmac, key, keylen);
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/* calculate A(1) from A(0) == seed */
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HMAC_UPDATE_SEED(hmac_a, label, labellen);
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HMAC_UPDATE_SEED(hmac_a, random1, random1len);
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HMAC_UPDATE_SEED(hmac_a, random2, random2len);
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HMAC_UPDATE_SEED(&hmac, label, labellen);
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HMAC_UPDATE_SEED(&hmac, random1, random1len);
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HMAC_UPDATE_SEED(&hmac, random2, random2len);
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dlen = dtls_hmac_finalize(hmac_a, A);
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dlen = dtls_hmac_finalize(&hmac, A);
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hmac_p = dtls_hmac_new(key, keylen);
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if (!hmac_p)
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goto error;
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while (len < buflen) {
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dtls_hmac_init(&hmac, key, keylen);
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dtls_hmac_update(&hmac, A, dlen);
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while (len + dlen < buflen) {
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HMAC_UPDATE_SEED(&hmac, label, labellen);
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HMAC_UPDATE_SEED(&hmac, random1, random1len);
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HMAC_UPDATE_SEED(&hmac, random2, random2len);
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/* FIXME: rewrite loop to avoid superflous call to dtls_hmac_init() */
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dtls_hmac_init(hmac_p, key, keylen);
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dtls_hmac_update(hmac_p, A, dlen);
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dlen = dtls_hmac_finalize(&hmac, tmp);
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HMAC_UPDATE_SEED(hmac_p, label, labellen);
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HMAC_UPDATE_SEED(hmac_p, random1, random1len);
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HMAC_UPDATE_SEED(hmac_p, random2, random2len);
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len += dtls_hmac_finalize(hmac_p, tmp);
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memcpy(buf, tmp, dlen);
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buf += dlen;
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if ((len + dlen) < buflen) {
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memcpy(&buf[len], tmp, dlen);
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len += dlen;
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}
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else {
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memcpy(&buf[len], tmp, buflen - len);
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break;
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}
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/* calculate A(i+1) */
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dtls_hmac_init(hmac_a, key, keylen);
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dtls_hmac_update(hmac_a, A, dlen);
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dtls_hmac_finalize(hmac_a, A);
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dtls_hmac_init(&hmac, key, keylen);
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dtls_hmac_update(&hmac, A, dlen);
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dtls_hmac_finalize(&hmac, A);
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}
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dtls_hmac_init(hmac_p, key, keylen);
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dtls_hmac_update(hmac_p, A, dlen);
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HMAC_UPDATE_SEED(hmac_p, label, labellen);
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HMAC_UPDATE_SEED(hmac_p, random1, random1len);
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HMAC_UPDATE_SEED(hmac_p, random2, random2len);
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dtls_hmac_finalize(hmac_p, tmp);
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memcpy(buf, tmp, buflen - len);
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error:
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dtls_hmac_free(hmac_a);
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dtls_hmac_free(hmac_p);
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/* prevent exposure of sensible data */
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memset(&hmac, 0, sizeof(hmac));
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memset(tmp, 0, sizeof(tmp));
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memset(A, 0, sizeof(A));
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return buflen;
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}
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7
dtls.c
7
dtls.c
@ -220,7 +220,6 @@ void
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dtls_init(void) {
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dtls_clock_init();
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crypto_init();
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dtls_hmac_storage_init();
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netq_init();
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peer_init();
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@ -362,11 +361,7 @@ dtls_create_cookie(dtls_context_t *ctx,
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* - compression method
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*/
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/* We use our own buffer as hmac_context instead of a dynamic buffer
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* created by dtls_hmac_new() to separate storage space for cookie
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* creation from storage that is used in real sessions. Note that
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* the buffer size must fit with the default hash algorithm (see
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* implementation of dtls_hmac_context_new()). */
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/* Note that the buffer size must fit with the default hash algorithm. */
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dtls_hmac_context_t hmac_context;
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dtls_hmac_init(&hmac_context, ctx->cookie_secret, DTLS_COOKIE_SECRET_LENGTH);
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63
hmac.c
63
hmac.c
@ -27,44 +27,6 @@
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#include "dtls_debug.h"
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#include "hmac.h"
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/* use malloc()/free() on platforms other than Contiki */
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#ifndef WITH_CONTIKI
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#include <stdlib.h>
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static inline dtls_hmac_context_t *
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dtls_hmac_context_new(void) {
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return (dtls_hmac_context_t *)malloc(sizeof(dtls_hmac_context_t));
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}
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static inline void
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dtls_hmac_context_free(dtls_hmac_context_t *ctx) {
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free(ctx);
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}
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void
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dtls_hmac_storage_init(void) {
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}
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#else /* WITH_CONTIKI */
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#include "memb.h"
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MEMB(hmac_context_storage, dtls_hmac_context_t, DTLS_HASH_MAX);
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static inline dtls_hmac_context_t *
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dtls_hmac_context_new(void) {
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return (dtls_hmac_context_t *)memb_alloc(&hmac_context_storage);
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}
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static inline void
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dtls_hmac_context_free(dtls_hmac_context_t *ctx) {
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memb_free(&hmac_context_storage, ctx);
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}
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void
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dtls_hmac_storage_init(void) {
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memb_init(&hmac_context_storage);
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}
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#endif /* WITH_CONTIKI */
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void
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dtls_hmac_update(dtls_hmac_context_t *ctx,
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const unsigned char *input, size_t ilen) {
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@ -72,17 +34,6 @@ dtls_hmac_update(dtls_hmac_context_t *ctx,
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dtls_hash_update(&ctx->data, input, ilen);
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}
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dtls_hmac_context_t *
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dtls_hmac_new(const unsigned char *key, size_t klen) {
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dtls_hmac_context_t *ctx;
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ctx = dtls_hmac_context_new();
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if (ctx)
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dtls_hmac_init(ctx, key, klen);
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return ctx;
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}
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void
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dtls_hmac_init(dtls_hmac_context_t *ctx, const unsigned char *key, size_t klen) {
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int i;
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@ -110,12 +61,6 @@ dtls_hmac_init(dtls_hmac_context_t *ctx, const unsigned char *key, size_t klen)
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ctx->pad[i] ^= 0x6A;
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}
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void
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dtls_hmac_free(dtls_hmac_context_t *ctx) {
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if (ctx)
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dtls_hmac_context_free(ctx);
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}
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int
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dtls_hmac_finalize(dtls_hmac_context_t *ctx, unsigned char *result) {
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unsigned char buf[DTLS_HMAC_DIGEST_SIZE];
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@ -141,16 +86,14 @@ dtls_hmac_finalize(dtls_hmac_context_t *ctx, unsigned char *result) {
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int main(int argc, char **argv) {
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static unsigned char buf[DTLS_HMAC_DIGEST_SIZE];
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size_t len, i;
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dtls_hmac_context_t *ctx;
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dtls_hmac_context_t ctx;
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if (argc < 3) {
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fprintf(stderr, "usage: %s key text", argv[0]);
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return -1;
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}
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dtls_hmac_storage_init();
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ctx = dtls_hmac_new(argv[1], strlen(argv[1]));
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assert(ctx);
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dtls_hmac_init(&ctx, argv[1], strlen(argv[1]));
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dtls_hmac_update(ctx, argv[2], strlen(argv[2]));
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len = dtls_hmac_finalize(ctx, buf);
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@ -159,8 +102,6 @@ int main(int argc, char **argv) {
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printf("%02x", buf[i]);
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printf("\n");
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dtls_hmac_free(ctx);
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return 0;
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}
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#endif
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22
hmac.h
22
hmac.h
@ -80,8 +80,6 @@ dtls_hash_finalize(unsigned char *buf, dtls_hash_t ctx) {
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}
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#endif /* WITH_SHA256 */
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void dtls_hmac_storage_init(void);
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/**
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* \defgroup HMAC Keyed-Hash Message Authentication Code (HMAC)
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* NIST Standard FIPS 198 describes the Keyed-Hash Message Authentication
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@ -125,26 +123,6 @@ typedef struct {
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*/
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void dtls_hmac_init(dtls_hmac_context_t *ctx, const unsigned char *key, size_t klen);
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/**
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* Allocates a new HMAC context \p ctx with the given secret key.
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* This function returns \c 1 if \c ctx has been set correctly, or \c
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* 0 or \c -1 otherwise. Note that this function allocates new storage
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* that must be released by dtls_hmac_free().
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*
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* \param key The secret key.
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* \param klen The length of \p key.
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* \return A new dtls_hmac_context_t object or @c NULL on error
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*/
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dtls_hmac_context_t *dtls_hmac_new(const unsigned char *key, size_t klen);
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/**
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* Releases the storage for @p ctx that has been allocated by
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* dtls_hmac_new().
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*
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* @param ctx The dtls_hmac_context_t to free.
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*/
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void dtls_hmac_free(dtls_hmac_context_t *ctx);
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/**
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* Updates the HMAC context with data from \p input.
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*
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