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Lock globalRNGMutex around all shared globalRNG access #10824

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Lock globalRNGMutex around all shared globalRNG access #10824

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62 changes: 43 additions & 19 deletions src/ssl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -15723,13 +15723,22 @@ int wolfSSL_RAND_write_file(const char* fname)
return 0;
}

if (wc_LockMutex(&globalRNGMutex) != 0) {
WOLFSSL_MSG("Bad Lock Mutex rng");
WC_FREE_VAR_EX(buf, NULL, DYNAMIC_TYPE_TMP_BUFFER);
return 0;
}

if (wc_RNG_GenerateBlock(&globalRNG, buf, (word32)bytes) != 0) {
wc_UnLockMutex(&globalRNGMutex);
WOLFSSL_MSG("Error generating random buffer");
bytes = 0;
}
else {
XFILE f;

wc_UnLockMutex(&globalRNGMutex);

#ifdef WOLFSSL_CHECK_MEM_ZERO
wc_MemZero_Add("wolfSSL_RAND_write_file buf", buf, bytes);
#endif
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Expand All @@ -15745,7 +15754,9 @@ int wolfSSL_RAND_write_file(const char* fname)
XFCLOSE(f);
}
}
ForceZero(buf, (word32)bytes);
/* wipe the whole buffer, not just (word32)bytes: error paths set
* bytes = 0 but the buffer may still hold generated random data */
ForceZero(buf, 1024);
#ifdef WOLFSSL_SMALL_STACK
XFREE(buf, NULL, DYNAMIC_TYPE_TMP_BUFFER);
#elif defined(WOLFSSL_CHECK_MEM_ZERO)
Expand Down Expand Up @@ -15879,21 +15890,30 @@ int wolfSSL_RAND_egd(const char* nm)
WOLFSSL_MSG("Error with initializing global RNG structure");
ret = WOLFSSL_FATAL_ERROR;
}
else if (wc_RNG_DRBG_Reseed(&globalRNG, (const byte*) buf, bytes)
!= 0) {
WOLFSSL_MSG("Error with reseeding DRBG structure");
else if (wc_LockMutex(&globalRNGMutex) != 0) {
WOLFSSL_MSG("Bad Lock Mutex rng");
ret = WOLFSSL_FATAL_ERROR;
}
#ifdef SHOW_SECRETS
else { /* print out entropy found only when no error occurred */
word32 i;
printf("EGD Entropy = ");
for (i = 0; i < bytes; i++) {
printf("%02X", buf[i]);
else {
if (wc_RNG_DRBG_Reseed(&globalRNG, (const byte*) buf, bytes)
!= 0) {
WOLFSSL_MSG("Error with reseeding DRBG structure");
ret = WOLFSSL_FATAL_ERROR;
}
wc_UnLockMutex(&globalRNGMutex);

#ifdef SHOW_SECRETS
/* print out entropy found only when no error occurred */
if (ret == WOLFSSL_SUCCESS) {
word32 i;
printf("EGD Entropy = ");
for (i = 0; i < bytes; i++) {
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printf("%02X", buf[i]);
}
printf("\n");
}
printf("\n");
#endif
}
#endif
}

ForceZero(buf, bytes);
Expand Down Expand Up @@ -16121,18 +16141,21 @@ int wolfSSL_RAND_poll(void)
WOLFSSL_MSG("Global RNG no Init");
return WOLFSSL_FAILURE;
}

/* lock intentionally covers wc_GenerateSeed as well, since it writes
* globalRNG.seed; do not narrow this scope or the seed write races */
if (wc_LockMutex(&globalRNGMutex) != 0) {
WOLFSSL_MSG("Bad Lock Mutex rng");
return WOLFSSL_FAILURE;
}

ret = wc_GenerateSeed(&globalRNG.seed, entropy, entropy_sz);
if (ret != 0) {
WOLFSSL_MSG("Bad wc_RNG_GenerateBlock");
WOLFSSL_MSG("Bad wc_GenerateSeed");
ret = WOLFSSL_FAILURE;
}
else {
#ifdef HAVE_HASHDRBG
if (wc_LockMutex(&globalRNGMutex) != 0) {
WOLFSSL_MSG("Bad Lock Mutex rng");
return ret;
}

ret = wc_RNG_DRBG_Reseed(&globalRNG, entropy, entropy_sz);
if (ret != 0) {
WOLFSSL_MSG("Error reseeding DRBG");
Expand All @@ -16141,7 +16164,6 @@ int wolfSSL_RAND_poll(void)
else {
ret = WOLFSSL_SUCCESS;
}
wc_UnLockMutex(&globalRNGMutex);
#elif defined(HAVE_INTEL_RDRAND)
WOLFSSL_MSG("Not polling with RAND_poll, RDRAND used without "
"HAVE_HASHDRBG");
Expand All @@ -16152,6 +16174,8 @@ int wolfSSL_RAND_poll(void)
#endif
}

wc_UnLockMutex(&globalRNGMutex);

return ret;
}

Expand Down
12 changes: 10 additions & 2 deletions src/ssl_p7p12.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1560,11 +1560,19 @@ int wolfSSL_SMIME_write_PKCS7(WOLFSSL_BIO* out, PKCS7* pkcs7, WOLFSSL_BIO* in,
ret = 0;
}

if ((ret > 0) && (wc_LockMutex(&globalRNGMutex) != 0)) {
WOLFSSL_MSG("Bad Lock Mutex rng");
ret = 0;
}

/* no need to generate random byte for null terminator (size-1) */
if ((ret > 0) && (wc_RNG_GenerateBlock(&globalRNG, (byte*)boundary,
sizeof(boundary) - 1 ) != 0)) {
if (ret > 0) {
if (wc_RNG_GenerateBlock(&globalRNG, (byte*)boundary,
sizeof(boundary) - 1 ) != 0) {
WOLFSSL_MSG("Error in wc_RNG_GenerateBlock");
ret = 0;
}
wc_UnLockMutex(&globalRNGMutex);
}

if (ret > 0) {
Expand Down
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