...on a partially destroyed domain.
viridian_time_domain_freeze() and viridian_time_vcpu_freeze() rely
(respectively) on the dynamically allocated per-domain and per-vcpu viridian
areas [1], which are freed during domain_relinquish_resources().
Because arch_domain_pause() can call viridian_domain_time_freeze() this
can lead to host crashes if e.g. a XEN_DOMCTL_pausedomain is issued after
domain_relinquish_resources() has run.
To prevent such crashes, this patch adds a check of is_dying into
viridian_time_domain_freeze(), and viridian_time_domain_thaw() which is
similarly vulnerable to indirection into freed memory.
NOTE: The patch also makes viridian_time_vcpu_freeze/thaw() static, since
they have no callers outside of the same source module.
[1] See commit e7a9b5e72f26 "viridian: separately allocate domain and vcpu
structures".
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
---
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Wei Liu <wl@xen.org>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
---
xen/arch/x86/hvm/viridian/time.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/xen/arch/x86/hvm/viridian/time.c b/xen/arch/x86/hvm/viridian/time.c
index ac087383c8..e80330a6ae 100644
--- a/xen/arch/x86/hvm/viridian/time.c
+++ b/xen/arch/x86/hvm/viridian/time.c
@@ -296,7 +296,7 @@ void viridian_time_poll_timers(struct vcpu *v)
poll_stimer(v, i);
}
-void viridian_time_vcpu_freeze(struct vcpu *v)
+static void viridian_time_vcpu_freeze(struct vcpu *v)
{
struct viridian_vcpu *vv = v->arch.hvm.viridian;
unsigned int i;
@@ -314,7 +314,7 @@ void viridian_time_vcpu_freeze(struct vcpu *v)
}
}
-void viridian_time_vcpu_thaw(struct vcpu *v)
+static void viridian_time_vcpu_thaw(struct vcpu *v)
{
struct viridian_vcpu *vv = v->arch.hvm.viridian;
unsigned int i;
@@ -336,7 +336,7 @@ void viridian_time_domain_freeze(const struct domain *d)
{
struct vcpu *v;
- if ( !is_viridian_domain(d) )
+ if ( d->is_dying || !is_viridian_domain(d) )
return;
for_each_vcpu ( d, v )
@@ -349,7 +349,7 @@ void viridian_time_domain_thaw(const struct domain *d)
{
struct vcpu *v;
- if ( !is_viridian_domain(d) )
+ if ( d->is_dying || !is_viridian_domain(d) )
return;
time_ref_count_thaw(d);
--
2.20.1.2.gb21ebb671
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
On Wed, Aug 21, 2019 at 09:22:58AM +0100, Paul Durrant wrote: > ...on a partially destroyed domain. > > viridian_time_domain_freeze() and viridian_time_vcpu_freeze() rely > (respectively) on the dynamically allocated per-domain and per-vcpu viridian > areas [1], which are freed during domain_relinquish_resources(). > Because arch_domain_pause() can call viridian_domain_time_freeze() this > can lead to host crashes if e.g. a XEN_DOMCTL_pausedomain is issued after > domain_relinquish_resources() has run. > > To prevent such crashes, this patch adds a check of is_dying into > viridian_time_domain_freeze(), and viridian_time_domain_thaw() which is > similarly vulnerable to indirection into freed memory. > > NOTE: The patch also makes viridian_time_vcpu_freeze/thaw() static, since > they have no callers outside of the same source module. > > [1] See commit e7a9b5e72f26 "viridian: separately allocate domain and vcpu > structures". > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com> Note you could also drop the viridian_ prefix to the now static functions. Thanks, Roger. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
> -----Original Message----- > From: Roger Pau Monne <roger.pau@citrix.com> > Sent: 21 August 2019 09:52 > To: Paul Durrant <Paul.Durrant@citrix.com> > Cc: xen-devel@lists.xenproject.org; Jan Beulich <jbeulich@suse.com>; Andrew Cooper > <Andrew.Cooper3@citrix.com>; Wei Liu <wl@xen.org> > Subject: Re: [PATCH] viridian: make viridian_time_domain_freeze() safe to call... > > On Wed, Aug 21, 2019 at 09:22:58AM +0100, Paul Durrant wrote: > > ...on a partially destroyed domain. > > > > viridian_time_domain_freeze() and viridian_time_vcpu_freeze() rely > > (respectively) on the dynamically allocated per-domain and per-vcpu viridian > > areas [1], which are freed during domain_relinquish_resources(). > > Because arch_domain_pause() can call viridian_domain_time_freeze() this > > can lead to host crashes if e.g. a XEN_DOMCTL_pausedomain is issued after > > domain_relinquish_resources() has run. > > > > To prevent such crashes, this patch adds a check of is_dying into > > viridian_time_domain_freeze(), and viridian_time_domain_thaw() which is > > similarly vulnerable to indirection into freed memory. > > > > NOTE: The patch also makes viridian_time_vcpu_freeze/thaw() static, since > > they have no callers outside of the same source module. > > > > [1] See commit e7a9b5e72f26 "viridian: separately allocate domain and vcpu > > structures". > > > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> > > Reviewed-by: Roger Pau Monné <roger.pau@citrix.com> > > Note you could also drop the viridian_ prefix to the now static > functions. > Yeah, they could be dropped. May be a friendly committer could do it? :-) Paul _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
On 21/08/2019 10:13, Paul Durrant wrote: >> -----Original Message----- >> From: Roger Pau Monne <roger.pau@citrix.com> >> Sent: 21 August 2019 09:52 >> To: Paul Durrant <Paul.Durrant@citrix.com> >> Cc: xen-devel@lists.xenproject.org; Jan Beulich <jbeulich@suse.com>; Andrew Cooper >> <Andrew.Cooper3@citrix.com>; Wei Liu <wl@xen.org> >> Subject: Re: [PATCH] viridian: make viridian_time_domain_freeze() safe to call... >> >> On Wed, Aug 21, 2019 at 09:22:58AM +0100, Paul Durrant wrote: >>> ...on a partially destroyed domain. >>> >>> viridian_time_domain_freeze() and viridian_time_vcpu_freeze() rely >>> (respectively) on the dynamically allocated per-domain and per-vcpu viridian >>> areas [1], which are freed during domain_relinquish_resources(). >>> Because arch_domain_pause() can call viridian_domain_time_freeze() this >>> can lead to host crashes if e.g. a XEN_DOMCTL_pausedomain is issued after >>> domain_relinquish_resources() has run. >>> >>> To prevent such crashes, this patch adds a check of is_dying into >>> viridian_time_domain_freeze(), and viridian_time_domain_thaw() which is >>> similarly vulnerable to indirection into freed memory. >>> >>> NOTE: The patch also makes viridian_time_vcpu_freeze/thaw() static, since >>> they have no callers outside of the same source module. >>> >>> [1] See commit e7a9b5e72f26 "viridian: separately allocate domain and vcpu >>> structures". >>> >>> Signed-off-by: Paul Durrant <paul.durrant@citrix.com> >> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com> >> >> Note you could also drop the viridian_ prefix to the now static >> functions. >> > Yeah, they could be dropped. May be a friendly committer could do it? :-) Done. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
© 2016 - 2024 Red Hat, Inc.