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Re: [PATCH] Fix buffer overrun found by Coverity
Tom Tromey wrote:
> >>>>> "Gary" == Gary Benson <gbenson@redhat.com> writes:
>
> Gary> I would have committed this as obvious, but the testsuite
> Gary> doesn't exercise this piece of code; I can't realistically
> Gary> say I've regression tested this change, so I'd like another
> Gary> pair of eyes on it to be sure.
>
> What about the fission-dwp.exp board maybe?
> Or one of the other boards.
Oh, good call, it does.
> Gary> - memset (ids, 255, (DW_SECT_MAX + 1) * sizeof (int32_t));
> Gary> - memset (ids_seen, 255, (DW_SECT_MAX + 1) * sizeof (int32_t));
> Gary> + memset (ids, 255, sizeof_ids);
> Gary> + memset (ids_seen, 255, sizeof (ids_seen));
>
> Later the code does this:
>
> if (id < DW_SECT_MIN || id > DW_SECT_MAX)
> {
> error (_("Dwarf Error: bad DWP hash table, bad section id %d"
> [...]
> ids_seen[id] = i;
> ids[i] = id;
>
> So I think it would be good to ensure that MAX_NR_V2_DWO_SECTIONS is
> >= DW_SECT_MAX + 1. At least if I'm understanding this properly.
I don't *think* it's necessary:
ids_seen is indexed by "id",
which is 1 <= id <= DW_SECT_MAX;
ids is indexed by "i",
which is 0 <= i < nr_columns,
and nr_columns is nr_columns <= MAX_NR_V2_DWO_SECTIONS,
so 0 <= i < MAX_NR_V2_DWO_SECTIONS.
i.e. the dimensions are right, it's just the memset which isn't.
I think!
Ok, so this one's built and regtested on RHEL 7.5 x86_64 now, with
the fission-dwp.exp board. Assuming the dimensions thing above is
correct, is this ok to commit?
Cheers,
Gary