diff options
| author |   Joerg Roedel <jroedel@suse.de> | 2015-11-17 16:11:36 +0100 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2015-12-14 15:37:47 +0100 |
| commit | 7b5cc1a9c9f4096555345c365508d727149553fe (patch) | |
| tree | a704d1bec65c7bda54af3dffbeca97feeb09c57c /drivers/iommu/amd_iommu_v2.c | |
| parent | Linux 4.4-rc5 (diff) | |
| download | linux-dev-7b5cc1a9c9f4096555345c365508d727149553fe.tar.xz linux-dev-7b5cc1a9c9f4096555345c365508d727149553fe.zip | |
iommu/amd: Do proper access checking before calling handle_mm_fault()
The handle_mm_fault function expects the caller to do the
access checks. Not doing so and calling the function with
wrong permissions is a bug (catched by a BUG_ON).
So fix this bug by adding proper access checking to the io
page-fault code in the AMD IOMMUv2 driver.
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Acked-By: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers/iommu/amd_iommu_v2.c')
| -rw-r--r-- | drivers/iommu/amd_iommu_v2.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c index d21d4edf7236..7caf2fa237f2 100644 --- a/drivers/iommu/amd_iommu_v2.c +++ b/drivers/iommu/amd_iommu_v2.c @@ -494,6 +494,22 @@ static void handle_fault_error(struct fault *fault) } } +static bool access_error(struct vm_area_struct *vma, struct fault *fault) +{ + unsigned long requested = 0; + + if (fault->flags & PPR_FAULT_EXEC) + requested |= VM_EXEC; + + if (fault->flags & PPR_FAULT_READ) + requested |= VM_READ; + + if (fault->flags & PPR_FAULT_WRITE) + requested |= VM_WRITE; + + return (requested & ~vma->vm_flags) != 0; +} + static void do_fault(struct work_struct *work) { struct fault *fault = container_of(work, struct fault, work); @@ -516,8 +532,8 @@ static void do_fault(struct work_struct *work) goto out; } - if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) { - /* handle_mm_fault would BUG_ON() */ + /* Check if we have the right permissions on the vma */ + if (access_error(vma, fault)) { up_read(&mm->mmap_sem); handle_fault_error(fault); goto out; |