Reviewers: Chris Evans, Mads Ager, vegorov,
Description:
Introduce a random entropy source which can optionally be provided at
initialization.
BUG=89462
Please review this at http://codereview.chromium.org/7395012/
SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge/
Affected files:
M include/v8.h
M src/api.cc
M src/v8.h
M src/v8.cc
Index: include/v8.h
===================================================================
--- include/v8.h (revision 8657)
+++ include/v8.h (working copy)
@@ -2801,7 +2801,14 @@
char** raw_data;
};
+
/**
+ * EntropySource is used as a callback function when v8 needs a source
+ * of cryptographically safe entropy.
+ */
+typedef bool (*EntropySource)(unsigned char* buffer, size_t length);
+
+/**
* Container class for static utility functions.
*/
class V8EXPORT V8 {
@@ -3026,6 +3033,12 @@
static bool Initialize();
/**
+ * Allows the host application to provide a callback which can be used
+ * as a source of entropy for random number generators.
+ */
+ static void SetEntropySource(EntropySource source);
+
+ /**
* Adjusts the amount of registered external memory. Used to give
* V8 an indication of the amount of externally allocated memory
* that is kept alive by JavaScript objects. V8 uses this to decide
Index: src/api.cc
===================================================================
--- src/api.cc (revision 8657)
+++ src/api.cc (working copy)
@@ -3933,6 +3933,11 @@
}
+void v8::V8::SetEntropySource(EntropySource source) {
+ i::V8::SetEntropySource(source);
+}
+
+
bool v8::V8::Dispose() {
i::Isolate* isolate = i::Isolate::Current();
if (!ApiCheck(isolate != NULL && isolate->IsDefaultIsolate(),
Index: src/v8.cc
===================================================================
--- src/v8.cc (revision 8657)
+++ src/v8.cc (working copy)
@@ -50,7 +50,10 @@
bool V8::has_fatal_error_ = false;
bool V8::use_crankshaft_ = true;
+static Mutex* entropy_mutex = OS::CreateMutex();
+static EntropySource entropy_source;
+
bool V8::Initialize(Deserializer* des) {
InitializeOncePerProcess();
@@ -102,8 +105,14 @@
static void seed_random(uint32_t* state) {
for (int i = 0; i < 2; ++i) {
- state[i] = FLAG_random_seed;
- while (state[i] == 0) {
+ if (FLAG_random_seed != NULL)
+ state[i] = FLAG_random_seed;
+ else if (entropy_source != NULL) {
+ uint32_t val;
+ ScopedLock lock(entropy_mutex);
+ entropy_source(reinterpret_cast<unsigned char*>(&val),
sizeof(uint32_t));
+ state[i] = val;
+ } else {
state[i] = random();
}
}
@@ -124,6 +133,11 @@
}
+void V8::SetEntropySource(EntropySource source) {
+ entropy_source = source;
+}
+
+
// Used by JavaScript APIs
uint32_t V8::Random(Isolate* isolate) {
ASSERT(isolate == Isolate::Current());
Index: src/v8.h
===================================================================
--- src/v8.h (revision 8657)
+++ src/v8.h (working copy)
@@ -91,6 +91,9 @@
static void FatalProcessOutOfMemory(const char* location,
bool take_snapshot = false);
+ // Allows a cryptographically safe entropy source to be provided
+ // for use in random number generation.
+ static void SetEntropySource(EntropySource source);
// Random number generation support. Not cryptographically safe.
static uint32_t Random(Isolate* isolate);
// We use random numbers internally in memory allocation and in the
--
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