565287 - GLContextProviderCGL potentially fails to load GL lib, based on uninitialized value

Status: RESOLVED FIXED

(Core :: Graphics: CanvasWebGL, defect)

Description

[Benoit Jacob [:bjacob] (mostly away)]

Attachment: Proposed patch

Looking at the file gfx/thebes/src/GLContextProviderCGL.mm, in the class CGLLibrary:

class CGLLibrary
{
public:
    CGLLibrary() : mInitialized(PR_FALSE) {}

    PRBool EnsureInitialized()
    {
        if (mInitialized) {
            return PR_TRUE;
        }
        if (!mOGLLibrary) {
            mOGLLibrary = PR_LoadLibrary("/System/Library/Frameworks/OpenGL.framework/OpenGL");
            if (!mOGLLibrary) {
                NS_WARNING("Couldn't load OpenGL Framework.");
                return PR_FALSE;
            }
        }
        
        mInitialized = PR_TRUE;
        return PR_TRUE;
    }

private:
    PRBool mInitialized;
    PRLibrary *mOGLLibrary;
};


The mOGLLibrary pointer is apparently used uninitialized here, and seems to only be set inside of the if (!mOGLLibrary) { ... }. So if by accident it happens to hold a nonzero value, the OpenGL library won't be loaded.

Proposed patch initializes mOGLLibrary to nsnull.

Disclaimer 1: I don't know Objective C++.
Disclaimer 2: I don't have a mac to test. Didn't even test compilation.

Comment 1

[Benoit Jacob [:bjacob] (mostly away)]

Attachment: Proposed patch, take 2, without trailing whitespace removal

Comment 2

[Bas Schouten (:bas.schouten)]

Pushed http://hg.mozilla.org/mozilla-central/rev/d9900a280f59.