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Last Comment Bug 494445 - MirrorWrappedNativeParent result sometimes uninitialized [@ js_LockGCThingRT ]
: MirrorWrappedNativeParent result sometimes uninitialized [@ js_LockGCThingRT ]
[sg:critical?] required by 455633
: crash, fixed1.9.0.12, fixed1.9.1
Product: Core
Classification: Components
Component: XPConnect (show other bugs)
: Trunk
: All All
: -- critical (vote)
: mozilla1.9.2a1
Assigned To: Peter Van der Beken [:peterv]
: Andrew Overholt [:overholt]
Depends on:
Blocks: 455633
  Show dependency treegraph
Reported: 2009-05-22 11:16 PDT by Peter Van der Beken [:peterv]
Modified: 2015-10-16 11:48 PDT (History)
8 users (show)
dsicore: blocking1.9.1+
dveditz: blocking1.9.0.12+
dveditz: wanted1.9.0.x+
peterv: in‑testsuite?
See Also:
Crash Signature:
QA Whiteboard:
Iteration: ---
Points: ---
Has Regression Range: ---
Has STR: ---

v1 (583 bytes, patch)
2009-05-22 11:16 PDT, Peter Van der Beken [:peterv]
mrbkap: review+
mrbkap: superreview+
Details | Diff | Splinter Review
v1.1 (887 bytes, patch)
2009-05-22 13:22 PDT, Peter Van der Beken [:peterv]
peterv: review+
peterv: superreview+
Details | Diff | Splinter Review

Description User image Peter Van der Beken [:peterv] 2009-05-22 11:16:05 PDT
Created attachment 379193 [details] [diff] [review]

I was looking at crash reports, there's a number of crashes in js_LockGCThingRT being called from XPCNativeWrapper::GetNewOrUsed. We call js_LockGCThingRT on the result of a call to MirrorWrappedNativeParent. Turns out that MirrorWrappedNativeParent sometimes returns PR_TRUE without initializing the result out pointer. I think setting it to null would be the right thing to do.

I think that this probably shows up under a number of different crash signatures, because XPCNativeWrapperCtor also calls MirrorWrappedNativeParent and it uses the uninitialized pointer to set it as a parent by calling JS_SetParent.

Nominating for blocking and marking security sensitive.
Comment 1 User image Damon Sicore (:damons) 2009-05-22 11:41:07 PDT
Talked this over with peterv a bit.  It's a nasty crash that results in an uninitialized pointer in the JS heap.  Since we have a pretty simple patch, and it's a security issue, I say we block and get this in asap.  If it comes down the the wire (*cough* may be there already) we can move on without this, but it doesn't seem to make sense to hold this back.
Comment 2 User image Blake Kaplan (:mrbkap) 2009-05-22 13:02:57 PDT
Comment on attachment 379193 [details] [diff] [review]

I spent a while tracking down why we do this mirroring at all (it isn't clear what we're protecting with it) and the result I came up with was that this patch makes things no worse than they are now wrt XPCNativeWrappers' parents.
Comment 3 User image Peter Van der Beken [:peterv] 2009-05-22 13:22:15 PDT
Created attachment 379226 [details] [diff] [review]

With NS_OUTPARAM for static analysis goodness. Carrying forward r/sr=mrbkap.
Comment 4 User image Peter Van der Beken [:peterv] 2009-05-22 15:01:31 PDT
BTW, this is not a problem on older branches (but would be if bug 455633 is landed there).
Comment 5 User image Daniel Veditz [:dveditz] 2009-05-25 20:08:36 PDT
setting wanted1.9.0.x? flag just so we don't keep triaging it when we go through trunk-fixed security bugs we haven't evaluated for the 1.9.0 branch. Better than a minus, which is true at the moment but might cause us to ignore this bug if bug 455633 is ever backported.
Comment 6 User image Daniel Veditz [:dveditz] 2009-07-05 22:46:17 PDT
We are landing bug 455633 on the 1.9.0 branch to fix regression bug 502458, therefore we need this fix too (rolled into the branch patch in bug 455633).
Comment 7 User image Daniel Veditz [:dveditz] 2009-07-05 23:09:27 PDT
mrbkap landed this fix with the fix for bug 455633 on the 1.9.0 branch.

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