Fixes

Author: arnaud-lb

ext/random/csprng.c

@@ -66,8 +66,7 @@
 static zend_atomic_int random_fd = ZEND_ATOMIC_INT_INITIALIZER(-1);
 #endif
 
-ZEND_ATTRIBUTE_NONNULL
-PHPAPI zend_result php_random_bytes_ex(void *bytes, size_t size, char *errstr, size_t errstr_size)
+ZEND_ATTRIBUTE_NONNULL PHPAPI zend_result php_random_bytes_ex(void *bytes, size_t size, char *errstr, size_t errstr_size)
 {
 #ifdef PHP_WIN32
 	/* Defer to CryptGenRandom on Windows */
@@ -211,7 +210,7 @@ PHPAPI zend_result php_random_bytes_ex(void *bytes, size_t size, char *errstr, s
 	return SUCCESS;
 }
 
-PHPAPI zend_result php_random_bytes(void *bytes, size_t size, bool should_throw)
+ZEND_ATTRIBUTE_NONNULL PHPAPI zend_result php_random_bytes(void *bytes, size_t size, bool should_throw)
 {
 	char errstr[128];
 	zend_result result = php_random_bytes_ex(bytes, size, errstr, sizeof(errstr));

ext/random/php_random_csprng.h

@@ -20,8 +20,9 @@
 
 # include "php.h"
 
-PHPAPI zend_result php_random_bytes(void *bytes, size_t size, bool should_throw);
-PHPAPI zend_result php_random_bytes_ex(void *bytes, size_t size, char *errstr, size_t errstr_size);
+ZEND_ATTRIBUTE_NONNULL PHPAPI zend_result php_random_bytes(void *bytes, size_t size, bool should_throw);
+
+ZEND_ATTRIBUTE_NONNULL PHPAPI zend_result php_random_bytes_ex(void *bytes, size_t size, char *errstr, size_t errstr_size);
 
 PHPAPI zend_result php_random_int(zend_long min, zend_long max, zend_long *result, bool should_throw);
 

ext/random/random.c

@@ -699,54 +699,50 @@ uint64_t php_random_generate_fallback_seed(void)
 	return php_random_generate_fallback_seed_ex(&RANDOM_G(fallback_seed_state));
 }
 
-static zend_result php_general_random_bytes_for_zend_initialize(php_random_state_for_zend *state)
+static void php_general_random_bytes_for_zend_initialize(php_random_state_for_zend *state)
 {
 	uint64_t t[4];
+	php_random_fallback_seed_state fallback_state = {
+		.initialized = false,
+	};
 
 	do {
-		char errstr[128];
-		if (php_random_bytes_ex(&t, sizeof(t), errstr, sizeof(errstr)) == FAILURE) {
+		/* Skip the CSPRNG if it has already failed */
+		if (!fallback_state.initialized) {
+			char errstr[128];
+			if (php_random_bytes_ex(&t, sizeof(t), errstr, sizeof(errstr)) == FAILURE) {
 #if ZEND_DEBUG
-			fprintf(stderr, "php_random_bytes_ex: Failed to generate a random seed: %s\n", errstr);
+				fprintf(stderr, "php_random_bytes_ex: Failed to generate a random seed: %s\n", errstr);
 #endif
-			return FAILURE;
+				goto fallback;
+			}
+		} else {
+fallback:
+			t[0] = php_random_generate_fallback_seed_ex(&fallback_state);
+			t[1] = php_random_generate_fallback_seed_ex(&fallback_state);
+			t[2] = php_random_generate_fallback_seed_ex(&fallback_state);
+			t[3] = php_random_generate_fallback_seed_ex(&fallback_state);
 		}
 	} while (UNEXPECTED(t[0] == 0 && t[1] == 0 && t[2] == 0 && t[3] == 0));
 
 	php_random_xoshiro256starstar_seed256(&state->xoshiro256starstar_state, t[0], t[1], t[2], t[3]);
-
-	return SUCCESS;
-}
-
-static void php_general_random_bytes_for_zend_initialize_fallback(php_random_state_for_zend *state)
-{
-	uint64_t t;
-	php_random_fallback_seed_state fallback_state;
-
-	do {
-		t = php_random_generate_fallback_seed_ex(&fallback_state);
-	} while (UNEXPECTED(t == 0));
-
-	php_random_xoshiro256starstar_seed64(&state->xoshiro256starstar_state, t);
 }
 
 PHPAPI zend_result php_general_random_bytes_for_zend(zend_utility_general_random_state *opaque_state, void *bytes, size_t size)
 {
 	php_random_state_for_zend *state = (php_random_state_for_zend*) opaque_state;
 
 	if (!state->initialized) {
-		if (php_general_random_bytes_for_zend_initialize(state) == FAILURE) {
-			php_general_random_bytes_for_zend_initialize_fallback(state);
-		}
+		php_general_random_bytes_for_zend_initialize(state);
 		state->initialized = true;
 	}
 
 	while (size > 0) {
 		php_random_result result = php_random_algo_xoshiro256starstar.generate(&state->xoshiro256starstar_state);
-		size_t chunk_size = MIN(size, sizeof(result.size));
-		memcpy(bytes, &result.result, chunk_size);
+		ZEND_ASSERT(result.size == 8 && sizeof(result.result) == 8);
+		size_t chunk_size = MIN(size, 8);
+		bytes = zend_mempcpy(bytes, &result.result, chunk_size);
 		size -= chunk_size;
-		bytes = (char*)bytes + chunk_size;
 	}
 
 	return SUCCESS;