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ssl: refactoring CyaSSL_BN_rand to reduce stack usage:

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--- variable decoded moved to the heap (1024 bytes saved)
--- variable tmpRNG moved to the heap (sizeof(RNG) saved)
This commit is contained in:
Moisés Guimarães 2014-09-15 16:57:34 -03:00
parent 68063874dc
commit 7cafb11791
1 changed files with 42 additions and 27 deletions
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69
src/ssl.c
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@ -10215,46 +10215,61 @@ int CyaSSL_mask_bits(CYASSL_BIGNUM* bn, int n)
/* SSL_SUCCESS on ok */
int CyaSSL_BN_rand(CYASSL_BIGNUM* bn, int bits, int top, int bottom)
{
int ret = 0;
int len = bits / 8;
RNG* rng = NULL;
#ifdef CYASSL_SMALL_STACK
RNG* tmpRNG = NULL;
byte* buff = NULL;
#else
RNG tmpRNG[1];
byte buff[1024];
RNG tmpRNG;
RNG* rng = &tmpRNG;
int len = bits/8;
#endif
(void)top;
(void)bottom;
CYASSL_MSG("CyaSSL_BN_rand");
if (bn == NULL || bn->internal == NULL) {
CYASSL_MSG("Bad function arguments");
return 0;
}
if (bits % 8)
len++;
if ( (InitRng(&tmpRNG)) != 0) {
CYASSL_MSG("Bad RNG Init, trying global");
if (initGlobalRNG == 0) {
CYASSL_MSG("Global RNG no Init");
return 0;
}
#ifdef CYASSL_SMALL_STACK
buff = (byte*)XMALLOC(1024, NULL, DYNAMIC_TYPE_TMP_BUFFER);
tmpRNG = (RNG*) XMALLOC(sizeof(RNG), NULL, DYNAMIC_TYPE_TMP_BUFFER);
if (buff == NULL || tmpRNG == NULL) {
XFREE(buff, NULL, DYNAMIC_TYPE_TMP_BUFFER);
XFREE(tmpRNG, NULL, DYNAMIC_TYPE_TMP_BUFFER);
return ret;
}
#endif
if (bn == NULL || bn->internal == NULL)
CYASSL_MSG("Bad function arguments");
else if (InitRng(tmpRNG) == 0)
rng = tmpRNG;
else if (initGlobalRNG)
rng = &globalRNG;
}
if (RNG_GenerateBlock(rng, buff, len) != 0) {
CYASSL_MSG("Bad RNG_GenerateBlock");
return 0;
}
if (rng) {
if (RNG_GenerateBlock(rng, buff, len) != 0)
CYASSL_MSG("Bad RNG_GenerateBlock");
else {
buff[0] |= 0x80 | 0x40;
buff[len-1] |= 0x01;
buff[0] |= 0x80 | 0x40;
buff[len-1] |= 0x01;
if (mp_read_unsigned_bin((mp_int*)bn->internal,buff,len) != MP_OKAY)
CYASSL_MSG("mp read bin failed");
else
ret = SSL_SUCCESS;
}
}
if (mp_read_unsigned_bin((mp_int*)bn->internal,buff,len) != MP_OKAY) {
CYASSL_MSG("mp read bin failed");
return 0;
}
#ifdef CYASSL_SMALL_STACK
XFREE(buff, NULL, DYNAMIC_TYPE_TMP_BUFFER);
XFREE(tmpRNG, NULL, DYNAMIC_TYPE_TMP_BUFFER);
#endif
return SSL_SUCCESS;
return ret;
}
@ -10285,7 +10300,7 @@ int CyaSSL_BN_hex2bn(CYASSL_BIGNUM** bn, const char* str)
#ifdef CYASSL_SMALL_STACK
decoded = (byte*)XMALLOC(decSz, NULL, DYNAMIC_TYPE_TMP_BUFFER);
if (decoded == NULL)
return 0;
return ret;
#endif
if (str == NULL)