Re: [PATCH 1/3] binfmt_elf: Respect error return from `regset->active'
From: Paul Burton <hidden>
Date: 2018-06-29 17:13:36
Also in:
linux-fsdevel, lkml, stable
Hi Alexander, On Tue, May 15, 2018 at 11:32:45PM +0100, Maciej W. Rozycki wrote:
The regset API documented in <linux/regset.h> defines -ENODEV as the
result of the `->active' handler to be used where the feature requested
is not available on the hardware found. However code handling core file
note generation in `fill_thread_core_info' interpretes any non-zero
result from the `->active' handler as the regset requested being active.
Consequently processing continues (and hopefully gracefully fails later
on) rather than being abandoned right away for the regset requested.
Fix the problem then by making the code proceed only if a positive
result is returned from the `->active' handler.
Cc: stable@vger.kernel.org # 2.6.25+
Fixes: 4206d3aa1978 ("elf core dump: notes user_regset")
Signed-off-by: Maciej W. Rozycki <redacted><snip>
quoted hunk ↗ jump to hunk
--- linux-jhogan-test.orig/fs/binfmt_elf.c 2018-03-21 17:14:55.000000000 +0000 +++ linux-jhogan-test/fs/binfmt_elf.c 2018-05-09 23:25:50.742255000 +0100@@ -1739,7 +1739,7 @@ static int fill_thread_core_info(struct const struct user_regset *regset = &view->regsets[i]; do_thread_regset_writeback(t->task, regset); if (regset->core_note_type && regset->get && - (!regset->active || regset->active(t->task, regset))) { + (!regset->active || regset->active(t->task, regset) > 0)) { int ret; size_t size = regset_size(t->task, regset); void *data = kmalloc(size, GFP_KERNEL);
This looks obviously right to me, although I don't think it affects
anything until commit 25847fb195ae ("powerpc/ptrace: Enable support for
NT_PPC_CGPR") in v4.8-rc1 & even then not in a harmful way so I'd drop
the stable tag.
You show up as maintainer for fs/binfmt_elf.c though, so before I go
applying this to mips-next does it look good to you?
Thanks,
Paul