diff mbox series

[GIT,PULL,05/17] s390/uv: fully validate the VMA before calling follow_page()

Message ID 20211031121104.14764-6-borntraeger@de.ibm.com (mailing list archive)
State New, archived
Headers show
Series [GIT,PULL,01/17] s390/gmap: validate VMA in __gmap_zap() | expand

Commit Message

Christian Borntraeger Oct. 31, 2021, 12:10 p.m. UTC 
From: David Hildenbrand <david@redhat.com>

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.

Fixes: 214d9bbcd3a6 ("s390/mm: provide memory management functions for protected KVM guests")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Link: https://lore.kernel.org/r/20210909162248.14969-6-david@redhat.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 arch/s390/kernel/uv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
index 5a656c7b7a67..f95ccbd39692 100644
--- a/arch/s390/kernel/uv.c
+++ b/arch/s390/kernel/uv.c
@@ -212,7 +212,7 @@  int gmap_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb)
 	uaddr = __gmap_translate(gmap, gaddr);
 	if (IS_ERR_VALUE(uaddr))
 		goto out;
-	vma = find_vma(gmap->mm, uaddr);
+	vma = vma_lookup(gmap->mm, uaddr);
 	if (!vma)
 		goto out;
 	/*