feedc0de/wolfssl
1
0
Fork 0
forked from wolfSSL/wolfssl
Code Pull Requests Activity

Merge pull request #352 from dgarske/DRBGSmallStack

Browse Source 
Fix to reduce stack usage in the hash-based random number generator h…
This commit is contained in:
John Safranek
2016-03-21 12:20:48 -07:00
parent 51a911c727 bda69decc1
commit d8fb4b6ee7
1 changed files with 69 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files

94
wolfcrypt/src/random.c
View File

@ -38,6 +38,8 @@
#define CUSTOM_RAND_TYPE byte #define CUSTOM_RAND_TYPE byte
#endif #endif
#define RNG_HEALTH_TEST_CHECK_SIZE (SHA256_DIGEST_SIZE * 4)
#ifdef HAVE_FIPS #ifdef HAVE_FIPS
int wc_GenerateSeed(OS_Seed* os, byte* seed, word32 sz) int wc_GenerateSeed(OS_Seed* os, byte* seed, word32 sz)
@ -608,42 +610,66 @@ int wc_RNG_HealthTest(int reseed, const byte* entropyA, word32 entropyASz,
const byte* entropyB, word32 entropyBSz, const byte* entropyB, word32 entropyBSz,
byte* output, word32 outputSz) byte* output, word32 outputSz)
{ {
DRBG drbg; int ret = -1;
DRBG* drbg;
#ifndef WOLFSSL_SMALL_STACK
DRBG drbg_var;
#endif
if (entropyA == NULL || output == NULL) if (entropyA == NULL || output == NULL) {
return BAD_FUNC_ARG; return BAD_FUNC_ARG;
}
if (reseed != 0 && entropyB == NULL) if (reseed != 0 && entropyB == NULL) {
return BAD_FUNC_ARG; return BAD_FUNC_ARG;
}
if (outputSz != (SHA256_DIGEST_SIZE * 4)) if (outputSz != RNG_HEALTH_TEST_CHECK_SIZE) {
return -1; return ret;
}
if (Hash_DRBG_Instantiate(&drbg, entropyA, entropyASz, NULL, 0) != 0) #ifdef WOLFSSL_SMALL_STACK
return -1; drbg = (struct DRBG*)XMALLOC(sizeof(DRBG), NULL, DYNAMIC_TYPE_RNG);
if (drbg == NULL) {
return MEMORY_E;
}
#else
drbg = &drbg_var;
#endif
if (Hash_DRBG_Instantiate(drbg, entropyA, entropyASz, NULL, 0) != 0) {
goto exit_rng_ht;
}
if (reseed) { if (reseed) {
if (Hash_DRBG_Reseed(&drbg, entropyB, entropyBSz) != 0) { if (Hash_DRBG_Reseed(drbg, entropyB, entropyBSz) != 0) {
Hash_DRBG_Uninstantiate(&drbg); goto exit_rng_ht;
return -1;
} }
} }
if (Hash_DRBG_Generate(&drbg, output, outputSz) != 0) { if (Hash_DRBG_Generate(drbg, output, outputSz) != 0) {
Hash_DRBG_Uninstantiate(&drbg); goto exit_rng_ht;
return -1;
} }
if (Hash_DRBG_Generate(&drbg, output, outputSz) != 0) { if (Hash_DRBG_Generate(drbg, output, outputSz) != 0) {
Hash_DRBG_Uninstantiate(&drbg); goto exit_rng_ht;
return -1; }
/* Mark success */
ret = 0;
exit_rng_ht:
/* This is safe to call even if Hash_DRBG_Instantiate fails */
if (Hash_DRBG_Uninstantiate(drbg) != 0) {
ret = -1;
} }
if (Hash_DRBG_Uninstantiate(&drbg) != 0) { #ifdef WOLFSSL_SMALL_STACK
return -1; XFREE(drbg, NULL, DYNAMIC_TYPE_RNG);
} #endif
return 0; return ret;
} }
@ -699,27 +725,45 @@ const byte outputB[] = {
static int wc_RNG_HealthTestLocal(int reseed) static int wc_RNG_HealthTestLocal(int reseed)
{ {
int ret = 0; int ret = 0;
byte check[SHA256_DIGEST_SIZE * 4]; #ifdef WOLFSSL_SMALL_STACK
byte* check;
#else
byte check[RNG_HEALTH_TEST_CHECK_SIZE];
#endif
#ifdef WOLFSSL_SMALL_STACK
check = (byte*)XMALLOC(RNG_HEALTH_TEST_CHECK_SIZE, NULL,
DYNAMIC_TYPE_TMP_BUFFER);
if (check == NULL) {
return MEMORY_E;
}
#endif
if (reseed) { if (reseed) {
ret = wc_RNG_HealthTest(1, entropyA, sizeof(entropyA), ret = wc_RNG_HealthTest(1, entropyA, sizeof(entropyA),
reseedEntropyA, sizeof(reseedEntropyA), reseedEntropyA, sizeof(reseedEntropyA),
check, sizeof(check)); check, RNG_HEALTH_TEST_CHECK_SIZE);
if (ret == 0) { if (ret == 0) {
if (ConstantCompare(check, outputA, sizeof(check)) != 0) if (ConstantCompare(check, outputA,
RNG_HEALTH_TEST_CHECK_SIZE) != 0)
ret = -1; ret = -1;
} }
} }
else { else {
ret = wc_RNG_HealthTest(0, entropyB, sizeof(entropyB), ret = wc_RNG_HealthTest(0, entropyB, sizeof(entropyB),
NULL, 0, NULL, 0,
check, sizeof(check)); check, RNG_HEALTH_TEST_CHECK_SIZE);
if (ret == 0) { if (ret == 0) {
if (ConstantCompare(check, outputB, sizeof(check)) != 0) if (ConstantCompare(check, outputB,
RNG_HEALTH_TEST_CHECK_SIZE) != 0)
ret = -1; ret = -1;
} }
} }
#ifdef WOLFSSL_SMALL_STACK
XFREE(check, NULL, DYNAMIC_TYPE_TMP_BUFFER);
#endif
return ret; return ret;
} }