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Re: [PATCH 1/3] libdw: Make srclines use a stable sort
- From: Josh Stone <jistone at redhat dot com>
- To: elfutils-devel at lists dot fedorahosted dot org
- Date: Tue, 16 Dec 2014 09:15:03 -0800
- Subject: Re: [PATCH 1/3] libdw: Make srclines use a stable sort
On 12/16/2014 02:10 AM, Mark Wielaard wrote:
>> I think src/elfcmp.c compare_Elf32_Word() is also wrong, as big u32
>> values could wrap int subtraction. I didn't find any others.
> Ah, missed that Elf32_Word is unsigned. There is an assert that makes
> sure it is at least as wide as an int, but that isn't enough indeed.
Oh actually, unsigned is a red herring. Even cmp(INT_MIN, 1) will get
the wrong answer if you use subtraction. Or cmp(0, INT_MIN), or many
more. Any time the span can be more than INT_MAX, it's a problem.
Maybe even more so with signed, since overflow is undefined!
> Proposed fix attached.