Bug 156799 – File URLs should be passed through 'fileSystemRepresentation' before use

• Status: RESOLVED
• Resolution: INVALID
• Component: WebKit Misc.

[Brent Fulgham]

We need to audit WebKit code to make sure that we always call fileSystemRepresentation before using a URL path as a file system path, and ideally make the compiler check that for us.

[Brent Fulgham]

It looks the following places need to be changed:

Internals::createFile
WebProcessProxy::hasAssumedReadAccessToURL
WebProcessProxy::checkURLReceivedFromWebProcess
WebPageProxy::loadFile

I think the point of fileSystemRepresentation is to ensure that the path is compatible with POSIX APIs. Are there reasons why we might want to deal with non-POSIX paths inside WebKit, up until the point where we actually pass them off to POSIX routines?

[Brent Fulgham]

I reviewed the various places where a file path is retrieved from a URL. It looks like in all cases we call fileSystemRepresentation on the path (or hand it to a function that in turn calls fileSystemRepresentation on its argument).

The two places in WebProcessProxy that use the method do so to retrieve a string for later use in comparing with a path. Since that paths in both places are retrieved without calling fileSystemRepresentation, it seemed better to leave these unmodified since the extra conversion wouldn't provide any additional safety, but would incur a runtime penalty.