Stefano Garzarella
2021-Feb-15 15:03 UTC
[PATCH for 5.10] vdpa_sim: fix param validation in vdpasim_get_config()
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 at vger.kernel.org> # 5.10.x >> Signed-off-by: Stefano Garzarella <sgarzare at 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"). Thanks, Stefano
Greg KH
2021-Feb-15 15:23 UTC
[PATCH for 5.10] vdpa_sim: fix param validation in vdpasim_get_config()
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 at vger.kernel.org> # 5.10.x > > > Signed-off-by: Stefano Garzarella <sgarzare at 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 :) 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. thanks, greg k-h