Add assertion to check whether shm files have maximum FileProtection of CompleteUnlessOpen

[Sihui Liu]

We have seen crashes where process gets killed because it tries accessing shm file after device is locked. We are suspecting this is because database protection class of shm file is set to be Complete by apps after it's created with lower protection level.

[Sihui Liu]

<rdar://problem/42685773>

[Sihui Liu]

Created attachment 368502 [details]
Patch

[Alex Christensen]

Comment on attachment 368502 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=368502&action=review

> Source/WebCore/platform/sql/SQLiteDatabase.cpp:154
> +        RELEASE_ASSERT(FileSystem::isSafeToUseMemoryMapForPath(shmFileName));

Why not just call makeSafeToUseMemoryMapForPath?

[Sihui Liu]

(In reply to Alex Christensen from comment #3)
> Comment on attachment 368502 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=368502&action=review
> 
> > Source/WebCore/platform/sql/SQLiteDatabase.cpp:154
> > +        RELEASE_ASSERT(FileSystem::isSafeToUseMemoryMapForPath(shmFileName));
> 
> Why not just call makeSafeToUseMemoryMapForPath?

If the crash is caused by the shm file being unsafe for mmap, we probably need change in sqlite instead of WebKit to ensure shm file is in correct protection class when the file is being used.

[Geoffrey Garen]

Comment on attachment 368502 [details]
Patch

r=me

[WebKit Commit Bot]

Comment on attachment 368502 [details]
Patch

Clearing flags on attachment: 368502

Committed r244921: <https://trac.webkit.org/changeset/244921>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.