* Re: [Xen-devel] [PATCH for-4.13] xen/xsm: flask: Prevent NULL deference in flask_assign_{, dt}device()
2019-10-04 16:42 [Xen-devel] [PATCH for-4.13] xen/xsm: flask: Prevent NULL deference in flask_assign_{, dt}device() Julien Grall
@ 2019-10-04 17:58 ` Daniel De Graaf
2019-10-05 12:05 ` Paul Durrant
` (2 subsequent siblings)
3 siblings, 0 replies; 7+ messages in thread
From: Daniel De Graaf @ 2019-10-04 17:58 UTC (permalink / raw)
To: Julien Grall, xen-devel; +Cc: jgross, paul
On 10/4/19 12:42 PM, Julien Grall wrote:
> flask_assign_{, dt}device() may be used to check whether you can test if
> a device is assigned. In this case, the domain will be NULL.
>
> However, flask_iommu_resource_use_perm() will be called and may end up
> to deference a NULL pointer. This can be prevented by moving the call
> after we check the validity for the domain pointer.
>
> Coverity-ID: 1486741
> Fixes: 71e617a6b8 ('use is_iommu_enabled() where appropriate...')
> Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
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^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [Xen-devel] [PATCH for-4.13] xen/xsm: flask: Prevent NULL deference in flask_assign_{, dt}device()
2019-10-04 16:42 [Xen-devel] [PATCH for-4.13] xen/xsm: flask: Prevent NULL deference in flask_assign_{, dt}device() Julien Grall
2019-10-04 17:58 ` Daniel De Graaf
@ 2019-10-05 12:05 ` Paul Durrant
2019-10-07 6:52 ` Jürgen Groß
2019-10-09 11:57 ` Artem Mygaiev
3 siblings, 0 replies; 7+ messages in thread
From: Paul Durrant @ 2019-10-05 12:05 UTC (permalink / raw)
To: Julien Grall; +Cc: Juergen Gross, xen-devel, Daniel De Graaf, Paul Durrant
On Fri, 4 Oct 2019 at 17:42, Julien Grall <julien.grall@arm.com> wrote:
>
> flask_assign_{, dt}device() may be used to check whether you can test if
> a device is assigned. In this case, the domain will be NULL.
>
> However, flask_iommu_resource_use_perm() will be called and may end up
> to deference a NULL pointer. This can be prevented by moving the call
> after we check the validity for the domain pointer.
>
> Coverity-ID: 1486741
> Fixes: 71e617a6b8 ('use is_iommu_enabled() where appropriate...')
> Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Paul Durrant <paul@xen.org>
> ---
> xen/xsm/flask/hooks.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
> index 3b30827764..cf7f25cda2 100644
> --- a/xen/xsm/flask/hooks.c
> +++ b/xen/xsm/flask/hooks.c
> @@ -1296,11 +1296,13 @@ static int flask_assign_device(struct domain *d, uint32_t machine_bdf)
> u32 dsid, rsid;
> int rc = -EPERM;
> struct avc_audit_data ad;
> - u32 dperm = flask_iommu_resource_use_perm(d);
> + u32 dperm;
>
> if ( !d )
> return flask_test_assign_device(machine_bdf);
>
> + dperm = flask_iommu_resource_use_perm(d);
> +
> rc = current_has_perm(d, SECCLASS_RESOURCE, RESOURCE__ADD);
> if ( rc )
> return rc;
> @@ -1355,11 +1357,13 @@ static int flask_assign_dtdevice(struct domain *d, const char *dtpath)
> u32 dsid, rsid;
> int rc = -EPERM;
> struct avc_audit_data ad;
> - u32 dperm = flask_iommu_resource_use_perm(d);
> + u32 dperm;
>
> if ( !d )
> return flask_test_assign_dtdevice(dtpath);
>
> + dperm = flask_iommu_resource_use_perm(d);
> +
> rc = current_has_perm(d, SECCLASS_RESOURCE, RESOURCE__ADD);
> if ( rc )
> return rc;
> --
> 2.11.0
>
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^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [Xen-devel] [PATCH for-4.13] xen/xsm: flask: Prevent NULL deference in flask_assign_{, dt}device()
2019-10-04 16:42 [Xen-devel] [PATCH for-4.13] xen/xsm: flask: Prevent NULL deference in flask_assign_{, dt}device() Julien Grall
2019-10-04 17:58 ` Daniel De Graaf
2019-10-05 12:05 ` Paul Durrant
@ 2019-10-07 6:52 ` Jürgen Groß
2019-10-09 11:57 ` Artem Mygaiev
3 siblings, 0 replies; 7+ messages in thread
From: Jürgen Groß @ 2019-10-07 6:52 UTC (permalink / raw)
To: Julien Grall, xen-devel; +Cc: Daniel De Graaf, paul
On 04.10.19 18:42, Julien Grall wrote:
> flask_assign_{, dt}device() may be used to check whether you can test if
> a device is assigned. In this case, the domain will be NULL.
>
> However, flask_iommu_resource_use_perm() will be called and may end up
> to deference a NULL pointer. This can be prevented by moving the call
> after we check the validity for the domain pointer.
>
> Coverity-ID: 1486741
> Fixes: 71e617a6b8 ('use is_iommu_enabled() where appropriate...')
> Signed-off-by: Julien Grall <julien.grall@arm.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Juergen
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^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [Xen-devel] [PATCH for-4.13] xen/xsm: flask: Prevent NULL deference in flask_assign_{, dt}device()
2019-10-04 16:42 [Xen-devel] [PATCH for-4.13] xen/xsm: flask: Prevent NULL deference in flask_assign_{, dt}device() Julien Grall
` (2 preceding siblings ...)
2019-10-07 6:52 ` Jürgen Groß
@ 2019-10-09 11:57 ` Artem Mygaiev
2019-10-10 14:48 ` Julien Grall
3 siblings, 1 reply; 7+ messages in thread
From: Artem Mygaiev @ 2019-10-09 11:57 UTC (permalink / raw)
To: julien.grall, xen-devel; +Cc: jgross, dgdegra, paul
Hi Julien
On Fri, 2019-10-04 at 17:42 +0100, Julien Grall wrote:
> flask_assign_{, dt}device() may be used to check whether you can test
> if
> a device is assigned. In this case, the domain will be NULL.
>
> However, flask_iommu_resource_use_perm() will be called and may end
> up
> to deference a NULL pointer. This can be prevented by moving the call
> after we check the validity for the domain pointer.
>
> Coverity-ID: 1486741
The correct CID is 1486742
> Fixes: 71e617a6b8 ('use is_iommu_enabled() where appropriate...')
> Signed-off-by: Julien Grall <
> julien.grall@arm.com
> >
> ---
> xen/xsm/flask/hooks.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
> index 3b30827764..cf7f25cda2 100644
> --- a/xen/xsm/flask/hooks.c
> +++ b/xen/xsm/flask/hooks.c
> @@ -1296,11 +1296,13 @@ static int flask_assign_device(struct domain
> *d, uint32_t machine_bdf)
> u32 dsid, rsid;
> int rc = -EPERM;
> struct avc_audit_data ad;
> - u32 dperm = flask_iommu_resource_use_perm(d);
> + u32 dperm;
>
> if ( !d )
> return flask_test_assign_device(machine_bdf);
>
> + dperm = flask_iommu_resource_use_perm(d);
> +
> rc = current_has_perm(d, SECCLASS_RESOURCE, RESOURCE__ADD);
> if ( rc )
> return rc;
> @@ -1355,11 +1357,13 @@ static int flask_assign_dtdevice(struct
> domain *d, const char *dtpath)
> u32 dsid, rsid;
> int rc = -EPERM;
> struct avc_audit_data ad;
> - u32 dperm = flask_iommu_resource_use_perm(d);
> + u32 dperm;
>
> if ( !d )
> return flask_test_assign_dtdevice(dtpath);
>
> + dperm = flask_iommu_resource_use_perm(d);
> +
> rc = current_has_perm(d, SECCLASS_RESOURCE, RESOURCE__ADD);
> if ( rc )
> return rc;
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^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [Xen-devel] [PATCH for-4.13] xen/xsm: flask: Prevent NULL deference in flask_assign_{, dt}device()
2019-10-09 11:57 ` Artem Mygaiev
@ 2019-10-10 14:48 ` Julien Grall
2019-10-10 15:07 ` Artem Mygaiev
0 siblings, 1 reply; 7+ messages in thread
From: Julien Grall @ 2019-10-10 14:48 UTC (permalink / raw)
To: Artem Mygaiev, xen-devel; +Cc: jgross, dgdegra, paul
On 09/10/2019 12:57, Artem Mygaiev wrote:
> Hi Julien
Hi,
> On Fri, 2019-10-04 at 17:42 +0100, Julien Grall wrote:
>> flask_assign_{, dt}device() may be used to check whether you can test
>> if
>> a device is assigned. In this case, the domain will be NULL.
>>
>> However, flask_iommu_resource_use_perm() will be called and may end
>> up
>> to deference a NULL pointer. This can be prevented by moving the call
>> after we check the validity for the domain pointer.
>>
>> Coverity-ID: 1486741
>
> The correct CID is 1486742
Hmmm yes. The coverity report e-mail is a bit confusing to read.
However, I have already committed the patch so we will have to leave with it :(.
Cheers,
--
Julien Grall
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^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [Xen-devel] [PATCH for-4.13] xen/xsm: flask: Prevent NULL deference in flask_assign_{, dt}device()
2019-10-10 14:48 ` Julien Grall
@ 2019-10-10 15:07 ` Artem Mygaiev
0 siblings, 0 replies; 7+ messages in thread
From: Artem Mygaiev @ 2019-10-10 15:07 UTC (permalink / raw)
To: julien.grall, xen-devel; +Cc: jgross, dgdegra, paul
Hi,
On Thu, 2019-10-10 at 15:48 +0100, Julien Grall wrote:
>
> On 09/10/2019 12:57, Artem Mygaiev wrote:
> > Hi Julien
>
> Hi,
>
> > On Fri, 2019-10-04 at 17:42 +0100, Julien Grall wrote:
> > > flask_assign_{, dt}device() may be used to check whether you can test
> > > if
> > > a device is assigned. In this case, the domain will be NULL.
> > >
> > > However, flask_iommu_resource_use_perm() will be called and may end
> > > up
> > > to deference a NULL pointer. This can be prevented by moving the call
> > > after we check the validity for the domain pointer.
> > >
> > > Coverity-ID: 1486741
> >
> > The correct CID is 1486742
>
> Hmmm yes. The coverity report e-mail is a bit confusing to read.
>
> However, I have already committed the patch so we will have to leave with it :(.
>
I guess the solution could be to fix another one and make a proper
commit comment with cross-reference :)
> Cheers,
>
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^ permalink raw reply [flat|nested] 7+ messages in thread