-stable review patch. If anyone has any objections, please let us know.
------------------
sys_shmdt() can manage shm segments which are covered by multiple vmas. (This
can happen when a user uses mprotect() after shmat().)
This works well if shm is aligned to PAGE_SIZE, but if not, the last
segment cannot be detached. It is because a comparison in sys_shmdt()
(vma->vm_end - addr) < size
addr == return address of shmat()
size == shmsize, argments to shmget()
size should be aligned to PAGE_SIZE before being compared with vma->vm_end,
which is aligned.
Signed-off-by: KAMEZAWA Hiroyuki <[email protected]>
Cc: Manfred Spraul <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Chris Wright <[email protected]>
---
ipc/shm.c | 1 +
1 file changed, 1 insertion(+)
--- linux-2.6.15.3.orig/ipc/shm.c
+++ linux-2.6.15.3/ipc/shm.c
@@ -863,6 +863,7 @@ asmlinkage long sys_shmdt(char __user *s
* could possibly have landed at. Also cast things to loff_t to
* prevent overflows and make comparisions vs. equal-width types.
*/
+ size = PAGE_ALIGN(size);
while (vma && (loff_t)(vma->vm_end - addr) <= size) {
next = vma->vm_next;
--
-
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