On Mon 2019-03-11 20:10:06, Alexey Dobriyan wrote: > On Mon, Mar 11, 2019 at 12:04:23PM +0100, Pavel Machek wrote: > > On Mon 2019-02-04 23:27:15, Alexey Dobriyan wrote: > > > Number of ELF program headers is 16-bit by spec, so total size > > > comfortably fits into "unsigned int". > > > > If it can't overflow, gcc should know too, and optimize checks > > out... right? > > Turns out it doesn't.
Tells me you are doing something wrong.
> > > @@ -429,13 +430,9 @@ static struct elf_phdr *load_elf_phdrs(struct elfhdr
> > > *elf_ex,
> > > goto out;
> > >
> > > /* Sanity check the number of program headers... */
> > > - if (elf_ex->e_phnum < 1 ||
> > > - elf_ex->e_phnum > 65536U / sizeof(struct elf_phdr))
> > > - goto out;
> > > -
> > > /* ...and their total size. */
> >
> > This is just wrong. You removed check for zero, and I'm pretty sure
> > sizeof() is not 1, so this one can trigger, too.
>
> No. ->e_phnum is 65535 max.
That does not invalidate my argument.
Pavel
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