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Re: [PATCH 05/10] vhost-backend: avoid overflow on memslots_limit
From: |
Roman Kagan |
Subject: |
Re: [PATCH 05/10] vhost-backend: avoid overflow on memslots_limit |
Date: |
Fri, 12 Nov 2021 14:10:17 +0300 |
On Fri, Nov 12, 2021 at 09:56:17AM +0000, Daniel P. Berrangé wrote:
> On Fri, Nov 12, 2021 at 10:46:46AM +0300, Roman Kagan wrote:
> > On Thu, Nov 11, 2021 at 06:59:43PM +0100, Philippe Mathieu-Daudé wrote:
> > > On 11/11/21 16:33, Roman Kagan wrote:
> > > > Fix the (hypothetical) potential problem when the value parsed out of
> > > > the vhost module parameter in sysfs overflows the return value from
> > > > vhost_kernel_memslots_limit.
> > > >
> > > > Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
> > > > ---
> > > > hw/virtio/vhost-backend.c | 2 +-
> > > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
> > > > index b65f8f7e97..44f7dbb243 100644
> > > > --- a/hw/virtio/vhost-backend.c
> > > > +++ b/hw/virtio/vhost-backend.c
> > > > @@ -58,7 +58,7 @@ static int vhost_kernel_memslots_limit(struct
> > > > vhost_dev *dev)
> > > > if
> > > > (g_file_get_contents("/sys/module/vhost/parameters/max_mem_regions",
> > > > &s, NULL, NULL)) {
> > > > uint64_t val = g_ascii_strtoull(s, NULL, 10);
> > >
> > > Would using qemu_strtou64() simplify this?
> >
> > I'm afraid not. None of the existing strtoXX converting functions has
> > the desired output range (0 < retval < INT_MAX), so the following
> > condition will remain necessary anyway; then it doesn't seem to matter
> > which particular parser is used to extract the value which is in the
> > range, so I left the one that was already there to reduce churn.
>
> If qemu_strtou64() can't handle all values in (0 < retval < INT_MAX)
> isn't that a bug in qemu_strtou64 ?
I must have been unclear. It sure can handle all values in this range;
the point is that the range check after it would still be needed, so
switching from g_ascii_strtoull to qemu_strtoXX saves nothing, therefore
I left it as it was.
Thanks,
Roman.
- Re: [PATCH 01/10] vhost-user-blk: reconnect on any error during realize, (continued)
Re: [PATCH 01/10] vhost-user-blk: reconnect on any error during realize, Raphael Norwitz, 2021/11/29
[PATCH 05/10] vhost-backend: avoid overflow on memslots_limit, Roman Kagan, 2021/11/11
[PATCH 07/10] vhost-vdpa: stick to -errno error return convention, Roman Kagan, 2021/11/11
[PATCH 02/10] chardev/char-socket: tcp_chr_recv: don't clobber errno, Roman Kagan, 2021/11/11
[PATCH 09/10] vhost: stick to -errno error return convention, Roman Kagan, 2021/11/11
[PATCH 10/10] vhost-user-blk: propagate error return from generic vhost, Roman Kagan, 2021/11/11
[PATCH 08/10] vhost-user: stick to -errno error return convention, Roman Kagan, 2021/11/11
[PATCH 04/10] chardev/char-fe: don't allow EAGAIN from blocking read, Roman Kagan, 2021/11/11