871462 - Clean up String API usages for dom/system/gonk

Status: RESOLVED FIXED

(Core :: DOM: Device Interfaces, defect)

Description

[Makoto Kato [:m_kato]]

Attachment: fix

Comment 1

[Makoto Kato [:m_kato]]

address value in AudioManager::Observe has use after free.  This is possible crash code.

Comment 2

[Doug Turner (:dougt)]

free after use is Security-Sensitive.

Comment 3

[Doug Turner (:dougt)]

other way around, of course.

Comment 4

[Doug Turner (:dougt)]

Comment on attachment 748718 [details] [diff] [review]
fix

Review of attachment 748718 [details] [diff] [review]:
-----------------------------------------------------------------

I *hate* our string classes.

::: dom/system/gonk/nsVolumeService.cpp
@@ -192,5 @@
>  
>  NS_IMETHODIMP
>  nsVolumeService::GetVolumeByPath(const nsAString& aPath, nsIVolume **aResult)
>  {
> -  nsCString utf8Path = NS_ConvertUTF16toUTF8(aPath);

Don't we have this pattern everywhere?

Comment 5

[Makoto Kato [:m_kato]]

String API is complex...

(In reply to Doug Turner (:dougt) from comment #4)
> Comment on attachment 748718 [details] [diff] [review]
> fix
> 
> Review of attachment 748718 [details] [diff] [review]:
> -----------------------------------------------------------------
> 
> I *hate* our string classes.
> 
> ::: dom/system/gonk/nsVolumeService.cpp
> @@ -192,5 @@
> >  
> >  NS_IMETHODIMP
> >  nsVolumeService::GetVolumeByPath(const nsAString& aPath, nsIVolume **aResult)
> >  {
> > -  nsCString utf8Path = NS_ConvertUTF16toUTF8(aPath);
> 
> Don't we have this pattern everywhere?

Years ago, although I clean up many code for this case, but I don't know now.

This pattern means,

NS_ConvertUTF18toUTF8 str(aPath);
nsCString utf8Path(str);
str.~str();

So This allocate unnecessary string object.  It is wasteful.

Comment 6

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Comment on attachment 748718 [details] [diff] [review]
fix

r=dbaron

At least only the first one looks like it's fixing a crash.

Comment 7

[Makoto Kato [:m_kato]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/92ba04c3ee67

Comment 8

[Makoto Kato [:m_kato]]

Attachment: for b2g18

Comment 9

[Makoto Kato [:m_kato]]

Comment on attachment 757756 [details] [diff] [review]
for b2g18

NOTE: Please see https://wiki.mozilla.org/Release_Management/B2G_Landing to better understand the B2G approval process and landings.

[Approval Request Comment]
Bug caused by (feature/regressing bug #): Bug 794903 and Bug 796300
User impact if declined: possible crash due to use-after-free bug
Testing completed: landed in m-i
Risk to taking this patch (and alternatives if risky): low
String or UUID changes made by this patch: no

Comment 10

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/92ba04c3ee67

Comment 11

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-b2g18/rev/0539d7c8c001

Comment 12

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-b2g18_v1_1_0_hd/rev/0539d7c8c001