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authorDavid Hildenbrand <david@redhat.com>2021-09-09 17:59:42 +0300
committerVasily Gorbik <gor@linux.ibm.com>2021-09-15 15:29:21 +0300
commita8b92b8c1eac8d655a97b1e90f4d83c25d9b9a18 (patch)
treeefc9ffdd54542816652aa34d9daa2b8230e375e6 /arch/s390/pci
parent6880fa6c56601bb8ed59df6c30fd390cc5f6dd8f (diff)
downloadlinux-a8b92b8c1eac8d655a97b1e90f4d83c25d9b9a18.tar.xz
s390/pci_mmio: fully validate the VMA before calling follow_pte()
We should not walk/touch page tables outside of VMA boundaries when holding only the mmap sem in read mode. Evil user space can modify the VMA layout just before this function runs and e.g., trigger races with page table removal code since commit dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap"). find_vma() does not check if the address is >= the VMA start address; use vma_lookup() instead. Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Fixes: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390/pci')
-rw-r--r--arch/s390/pci/pci_mmio.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c
index ae683aa623ac..c5b35ea129cf 100644
--- a/arch/s390/pci/pci_mmio.c
+++ b/arch/s390/pci/pci_mmio.c
@@ -159,7 +159,7 @@ SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
mmap_read_lock(current->mm);
ret = -EINVAL;
- vma = find_vma(current->mm, mmio_addr);
+ vma = vma_lookup(current->mm, mmio_addr);
if (!vma)
goto out_unlock_mmap;
if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
@@ -298,7 +298,7 @@ SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
mmap_read_lock(current->mm);
ret = -EINVAL;
- vma = find_vma(current->mm, mmio_addr);
+ vma = vma_lookup(current->mm, mmio_addr);
if (!vma)
goto out_unlock_mmap;
if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))