[haiku-bugs] Re: [Haiku] #10259: CDDA-related KDL: ASCII string corrupts kernel structures
- From: "ttcoder" <trac@xxxxxxxxxxxx>
- Date: Sat, 28 Mar 2015 20:41:56 -0000
#10259: CDDA-related KDL: ASCII string corrupts kernel structures
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Reporter: ttcoder | Owner: axeld
Type: bug | Status: closed
Priority: normal | Milestone: R1
Component: File Systems/cdda | Version: R1/Development
Resolution: fixed | Keywords:
Blocked By: | Blocking:
Has a Patch: 0 | Platform: All
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Comment (by ttcoder):
Looks like a buffer re-use optimization done wrong.. (Donald Knuth would
have something to say about that, something like "premature optimization
is the root(fs) of all evil" 8-).. There's a bit of that in Haiku.. But we
still love you guys :-b
Anyway big kudos to you Michael; went on a hunt for other tickets/symptoms
beside the 3 closed, that you might get credited with fixing too.
I'm guessing the kernel "guarded heap" could have helped find this out-of-
bounds write.. But as pulkomandy noted in 11718 it's impossible to run
Haiku with it these days, not even with 8 GB RAM in Haiku x64. Maybe that
guarded heap could be modified to allow guarding only one part of the OS
at a time (probably not easy: malloc looks like malloc looks like malloc,
no matter which kernel add-on calls it eh ?)
Or maybe the slab debugger mentionned by bonefish in #comment:8 is the one
to use in that kind of situation ?
Also interesting that Coverity did not tag that faulty strcpy, it's
probably beyond it's heuristics' powers.. (but I'm biased against static
analysis tools anyway).
Next time something like that occurs I ''have'' to think of going for
broke and make the string suspected of a buffer overrun even ''bigger'':
in this ticket's case, renaming the CD to a 250 bytes long name (instead
of the puny 30 bytes or so of a typical cdda) would have likely crashed
much faster and much more reliably, making it much easier to fix.
--
Ticket URL: <https://dev.haiku-os.org/ticket/10259#comment:13>
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