linux-kernel - [PATCH 2/2] vfio iommu type1: fix the testing of capability for remote task

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Date:   Thu, 22 Dec 2016 00:10:16 +0800
From:   Jike Song <jike.song@...el.com>
To:     serge@...lyn.com, alex.williamson@...hat.com
Cc:     linux-security-module@...r.kernel.org, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, kwankhede@...dia.com,
        kraxel@...hat.com, jike.song@...el.com
Subject: [PATCH 2/2] vfio iommu type1: fix the testing of capability for remote task

Before the mdev enhancement type1 iommu used capable() to test the
capability of current task; in the course of mdev development a
new requirement, testing for another task other than current, was
raised.  ns_capable() was used for this purpose, however it still
tests current, the only difference is, in a specified namespace.

Fix it by using has_capability() instead, which tests the cap for
specified task in init_user_ns, the same namespace as capable().

Cc: Alex Williamson <alex.williamson@...hat.com>
Cc: Kirti Wankhede <kwankhede@...dia.com>
Cc: Gerd Hoffmann <kraxel@...hat.com>
Signed-off-by: Jike Song <jike.song@...el.com>
---
 drivers/vfio/vfio_iommu_type1.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index f3726ba..b54aedf 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -394,8 +394,7 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
 				  long npage, unsigned long *pfn_base)
 {
 	unsigned long limit;
-	bool lock_cap = ns_capable(task_active_pid_ns(dma->task)->user_ns,
-				   CAP_IPC_LOCK);
+	bool lock_cap = has_capability(dma->task, CAP_IPC_LOCK);
 	struct mm_struct *mm;
 	long ret, i = 0, lock_acct = 0;
 	bool rsvd;
@@ -491,8 +490,7 @@ static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr,
 				  unsigned long *pfn_base, bool do_accounting)
 {
 	unsigned long limit;
-	bool lock_cap = ns_capable(task_active_pid_ns(dma->task)->user_ns,
-				   CAP_IPC_LOCK);
+	bool lock_cap = has_capability(dma->task, CAP_IPC_LOCK);
 	struct mm_struct *mm;
 	int ret;
 	bool rsvd;
-- 
2.4.4.488.gdf97e5d