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authorHeiko Carstens <heiko.carstens@de.ibm.com>2012-10-22 15:49:02 +0200
committerBen Hutchings <ben@decadent.org.uk>2012-12-06 11:20:05 +0000
commit63d0412fb38ee2f13e7d68b1f2b136ea91d52bc2 (patch)
tree2068f976f3c278b466d2a595b5f5fc5ef2ceb94e /arch/s390/mm
parent8a3a3f4a507d46b1c22c923733b172eebcf188f1 (diff)
s390/gup: add missing TASK_SIZE check to get_user_pages_fast()
commit d55c4c613fc4d4ad2ba0fc6fa2b57176d420f7e4 upstream. When walking page tables we need to make sure that everything is within bounds of the ASCE limit of the task's address space. Otherwise we might calculate e.g. a pud pointer which is not within a pud and dereference it. So check against TASK_SIZE (which is the ASCE limit) before walking page tables. Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch/s390/mm')
-rw-r--r--arch/s390/mm/gup.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c
index 65cb06e2af4..4ccf9f54355 100644
--- a/arch/s390/mm/gup.c
+++ b/arch/s390/mm/gup.c
@@ -183,7 +183,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
addr = start;
len = (unsigned long) nr_pages << PAGE_SHIFT;
end = start + len;
- if (end < start)
+ if ((end < start) || (end > TASK_SIZE))
goto slow_irqon;
/*