Changeset 39510 in webkit for trunk/JavaScriptCore/wtf/RandomNumber.cpp

Timestamp:

Dec 29, 2008, 11:21:03 PM (16 years ago)

Author:

[email protected]

Message:

<rdar://problem/6358108> Insecure randomness in Math.random() leads to user tracking

Reviewed by Mark Rowe

Switch to arc4random on PLATFORM(DARWIN), this is ~1.5x slower than random(), but the
it is still so fast that there is no fathomable way it could be a bottleneck for anything.

randomNumber is called in two places

• During form submission where it is called once per form
• Math.random in JSC. For this difference to show up you have to be looping on a cached local copy of random, for a large (>10000) calls.

No change in SunSpider.

File:

• trunk/JavaScriptCore/wtf/RandomNumber.cpp (modified) (1 diff)

trunk/JavaScriptCore/wtf/RandomNumber.cpp

@@ -51 +51 @@
     return static_cast<double>(u) / (static_cast<double>(UINT_MAX) + 1.0);
 #elif PLATFORM(DARWIN)
-    return static_cast<double>(random()) / (static_cast<double>(RAND_MAX) + 1.0);
+    return static_cast<double>(arc4random()) / (static_cast<double>(UINT32_MAX) + 1.0);
 #else
     return static_cast<double>(rand()) / (static_cast<double>(RAND_MAX) + 1.0);