Messages in this thread | | | From | Arnd Bergmann <> | Date | Tue, 22 Oct 2019 14:45:07 +0200 | Subject | Re: [PATCH v2] aio: Fix io_pgetevents() struct __compat_aio_sigset layout |
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On Tue, Oct 22, 2019 at 12:49 AM Guillem Jover <guillem@hadrons.org> wrote: > > This type is used to pass the sigset_t from userland to the kernel, > but it was using the kernel native pointer type for the member > representing the compat userland pointer to the userland sigset_t. > > This messes up the layout, and makes the kernel eat up both the > userland pointer and the size into the kernel pointer, and then > reads garbage into the kernel sigsetsize. Which makes the sigset_t > size consistency check fail, and consequently the syscall always > returns -EINVAL. > > This breaks both libaio and strace on 32-bit userland running on 64-bit > kernels. And there are apparently no users in the wild of the current > broken layout (at least according to codesearch.debian.org and a brief > check over github.com search). So it looks safe to fix this directly > in the kernel, instead of either letting userland deal with this > permanently with the additional overhead or trying to make the syscall > infer what layout userland used, even though this is also being worked > around in libaio to temporarily cope with kernels that have not yet > been fixed. > > We use a proper compat_uptr_t instead of a compat_sigset_t pointer. > > Fixes: 7a074e96dee6 ("aio: implement io_pgetevents") > Signed-off-by: Guillem Jover <guillem@hadrons.org>
When resending a patch that has already been reviewed, please add the tags you received so they get picked up into the final changeset as well:
Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Let's make sure this also gets added to stable kernels
Cc: <stable@vger.kernel.org> # v4.18+
Finally (if you like) Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Arnd
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