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[Bug binutils/24132] A suspicious unsigned integer overflow which may by
poppeter1982 at gmail dot com
[Bug binutils/24132] A suspicious unsigned integer overflow which may bypass a check
Fri, 25 Jan 2019 19:02:40 +0000
--- Comment #2 from poppeter1982 at gmail dot com ---
nickc at redhat dot com <address@hidden> 于2019年1月25日周五
> Nick Clifton <nickc at redhat dot com> changed:
> What |Removed |Added
> CC| |nickc at redhat dot com
> --- Comment #1 from Nick Clifton <nickc at redhat dot com> ---
> (In reply to poppeter1982 from comment #0)
> Hi Peng,
> > if (dynamic_addr + dynamic_size >= filedata->file_size)
> > If you compile readelf with -fsanitize=unsigned-integer-overflow
> The version of gcc that I am using (8.2.1 on Fedora 29) does not support
> a -fsanitize=unsigned-integer-overflow option. Is this a new feature ?
I used clang as the compilation frontend
> > and run
> > ./readelf -a input, it is found that dynamic_addr + dynamic_size
> > and may bypass the check. Can you please help verify if it is a true
> > positive
> I added a printf statement before the check to examine the values of
> these variables:
> fprintf (stderr, "addr %lx size %llx file %llx plus %llx\n",
> dynamic_addr, dynamic_size, filedata->file_size,
> dynamic_addr + dynamic_size);
> But it appears that the arithmetic works:
> addr 22000016 size 60000e002200002f file c190d plus 60000e0044000045
> readelf: Error: the dynamic segment offset + size exceeds the size of the
> (This is with a 32-bit toolchain, which I presume you are using. You
> did not actually specify how you configured your binutils build).
> The point is that the dynamic_size and file_size variables are both
> unsigned long long types, and so the arithmetic does not overflow.
> So I think that the check should be OK.
I compiled binutils in 64-bits platform, and carefully checked the output.
I agree with you that based on this input, the check will not be bypassed.
However, do you think there exist the possibility that this check will fail
I reported a similar issue
the check fails due to overflow in this case.
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