Messages in this thread | | | Date | Tue, 16 Feb 2021 14:55:09 +0100 | From | Stefano Garzarella <> | Subject | Re: [PATCH for 5.10] vdpa_sim: fix param validation in vdpasim_get_config() |
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On Mon, Feb 15, 2021 at 04:23:54PM +0100, Greg KH wrote: >On Mon, Feb 15, 2021 at 04:03:21PM +0100, Stefano Garzarella wrote: >> On Mon, Feb 15, 2021 at 03:32:19PM +0100, Greg KH wrote: >> > On Thu, Feb 11, 2021 at 05:25:19PM +0100, Stefano Garzarella wrote: >> > > Commit 65b709586e222fa6ffd4166ac7fdb5d5dad113ee upstream. >> > >> > No, this really is not that commit, so please do not say it is. >> >> Oops, sorry. >> >> > >> > > Before this patch, if 'offset + len' was equal to >> > > sizeof(struct virtio_net_config), the entire buffer wasn't filled, >> > > returning incorrect values to the caller. >> > > >> > > Since 'vdpasim->config' type is 'struct virtio_net_config', we can >> > > safely copy its content under this condition. >> > > >> > > Commit 65b709586e22 ("vdpa_sim: add get_config callback in >> > > vdpasim_dev_attr") unintentionally solved it upstream while >> > > refactoring vdpa_sim.c to support multiple devices. But we don't want >> > > to backport it to stable branches as it contains many changes. >> > > >> > > Fixes: 2c53d0f64c06 ("vdpasim: vDPA device simulator") >> > > Cc: <stable@vger.kernel.org> # 5.10.x >> > > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> >> > > --- >> > > drivers/vdpa/vdpa_sim/vdpa_sim.c | 2 +- >> > > 1 file changed, 1 insertion(+), 1 deletion(-) >> > > >> > > diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c >> > > index 6a90fdb9cbfc..8ca178d7b02f 100644 >> > > --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c >> > > +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c >> > > @@ -572,7 +572,7 @@ static void vdpasim_get_config(struct vdpa_device *vdpa, unsigned int offset, >> > > { >> > > struct vdpasim *vdpasim = vdpa_to_sim(vdpa); >> > > >> > > - if (offset + len < sizeof(struct virtio_net_config)) >> > > + if (offset + len <= sizeof(struct virtio_net_config)) >> > > memcpy(buf, (u8 *)&vdpasim->config + offset, len); >> > > } >> > >> > I'll be glad to take a one-off patch, but why can't we take the real >> > upstream patch? That is always the better long-term solution, right? >> >> Because that patch depends on the following patches merged in v5.11-rc1 >> while refactoring vdpa_sim: >> f37cbbc65178 vdpa_sim: make 'config' generic and usable for any device type >> cf1a3b35382c vdpa_sim: store parsed MAC address in a buffer >> a13b5918fdd0 vdpa_sim: add work_fn in vdpasim_dev_attr >> 011c35bac5ef vdpa_sim: add supported_features field in vdpasim_dev_attr >> 2f8f46188805 vdpa_sim: add device id field in vdpasim_dev_attr >> 6c6e28fe4579 vdpa_sim: add struct vdpasim_dev_attr for device attributes >> 36a9c3063025 vdpa_sim: rename vdpasim_config_ops variables >> 423248d60d2b vdpa_sim: remove hard-coded virtq count >> >> Maybe we can skip some of them, but IMHO should be less risky to apply only >> this change. >> >> If you want I can try to figure out the minimum sub-set of patches needed >> for 65b709586e22 ("vdpa_sim: add get_config callback in vdpasim_dev_attr"). > >The minimum is always nice :) >
The minimum set, including the patch that fixes the issue, is the following:
65b709586e22 vdpa_sim: add get_config callback in vdpasim_dev_attr f37cbbc65178 vdpa_sim: make 'config' generic and usable for any device type cf1a3b35382c vdpa_sim: store parsed MAC address in a buffer 6c6e28fe4579 vdpa_sim: add struct vdpasim_dev_attr for device attributes 423248d60d2b vdpa_sim: remove hard-coded virtq count
The patches apply fairly cleanly. There are a few contextual differences due to the lack of the other patches:
$ git backport-diff -u master -r linux-5.10.y..HEAD Key: [----] : patches are identical [####] : number of functional differences between upstream/downstream patch [down] : patch is downstream-only The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively
001/5:[----] [--] 'vdpa_sim: remove hard-coded virtq count' 002/5:[----] [-C] 'vdpa_sim: add struct vdpasim_dev_attr for device attributes' 003/5:[----] [--] 'vdpa_sim: store parsed MAC address in a buffer' 004/5:[----] [-C] 'vdpa_sim: make 'config' generic and usable for any device type' 005/5:[----] [-C] 'vdpa_sim: add get_config callback in vdpasim_dev_attr'
>If it's just too much churn for no good reason, then yes, the one-line >change above will be ok, but you need to document the heck out of why >this is not upstream and that it is a one-off thing. >
Shortly I'll send the series to stable@vger.kernel.org so you can judge if it's okay or better to resend this patch with a better description.
Thanks Stefano
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