From: Artem Mygaiev <Artem_Mygaiev@epam.com>
To: "julien.grall@arm.com" <julien.grall@arm.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: "jgross@suse.com" <jgross@suse.com>,
"dgdegra@tycho.nsa.gov" <dgdegra@tycho.nsa.gov>,
"paul@xen.org" <paul@xen.org>
Subject: Re: [Xen-devel] [PATCH for-4.13] xen/xsm: flask: Prevent NULL deference in flask_assign_{, dt}device()
Date: Wed, 9 Oct 2019 11:57:54 +0000 [thread overview]
Message-ID: <f262a8aeb67c6aabde80b1e6cdae6f19c077ff11.camel@epam.com> (raw)
In-Reply-To: <20191004164243.30822-1-julien.grall@arm.com>
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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next prev parent reply other threads:[~2019-10-09 11:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
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 [this message]
2019-10-10 14:48 ` Julien Grall
2019-10-10 15:07 ` Artem Mygaiev
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