From: Julien Grall <julien.grall@arm.com>
To: xen-devel@lists.xenproject.org
Cc: jgross@suse.com, Julien Grall <julien.grall@arm.com>,
Daniel De Graaf <dgdegra@tycho.nsa.gov>,
paul@xen.org
Subject: [Xen-devel] [PATCH for-4.13] xen/xsm: flask: Prevent NULL deference in flask_assign_{, dt}device()
Date: Fri, 4 Oct 2019 17:42:43 +0100 [thread overview]
Message-ID: <20191004164243.30822-1-julien.grall@arm.com> (raw)
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>
---
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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next reply other threads:[~2019-10-04 16:43 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-04 16:42 Julien Grall [this message]
2019-10-04 17:58 ` [Xen-devel] [PATCH for-4.13] xen/xsm: flask: Prevent NULL deference in flask_assign_{, dt}device() Daniel De Graaf
2019-10-05 12:05 ` Paul Durrant
2019-10-07 6:52 ` Jürgen Groß
2019-10-09 11:57 ` Artem Mygaiev
2019-10-10 14:48 ` Julien Grall
2019-10-10 15:07 ` Artem Mygaiev
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