From: Peter Edwards <peadar@arista.com>
To: Andreas Schwab <schwab@suse.de>
Cc: Peter Edwards via Libc-alpha <libc-alpha@sourceware.org>
Subject: Re: [PATCH] elf: Avoid pointer-arithmetic underflow in ldconfig
Date: Mon, 4 Sep 2023 13:32:12 +0100 [thread overview]
Message-ID: <CAO1X7jtwruthdm5ZgTBAeOptpQYT8OHgn7-tTNaRc+AqtA2UGQ@mail.gmail.com> (raw)
In-Reply-To: <mvmmsy22nly.fsf@suse.de>
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On Mon, 4 Sept 2023 at 12:18, Andreas Schwab <schwab@suse.de> wrote:
>
> > + loadoff = (uintptr_t)segment->p_vaddr -
> > + (uintptr_t)segment->p_offset;
>
> Shouldn't that use a signed difference, then? Since loadoff is now
> ptrdiff_t, I would expect the use of ptrdiff_t for the casts.
>
Hi,
For the 32-bit code, we were previously relying on the behaviour of
wrap-around on the unsigned type, this just extends that reliance to a
pointer-sized integer on the 64 bit platform.
I guess intptr_t might be a better option than uintptr_t? I would think
ptrdiff_t would really only be useful as the difference between two
pointers (and I guess if you want to be pedantic, might not always be the
same as the size of a pointer).
next prev parent reply other threads:[~2023-09-04 12:32 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-04 10:54 Peter Edwards
2023-09-04 11:18 ` Andreas Schwab
2023-09-04 12:32 ` Peter Edwards [this message]
2023-09-04 14:27 ` Andreas Schwab
2023-09-04 15:34 ` Peter Edwards
2023-09-04 16:26 ` Andreas Schwab
2023-09-04 16:28 ` Peter Edwards
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