This is a patch for a problem of shmdt().
It is found by a test, not a serious problem.
-- Kame
sys_shmdt() can manages shm segments which is 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]>
Index: linux-2.6.16-rc2.org/ipc/shm.c
===================================================================
--- linux-2.6.16-rc2.org.orig/ipc/shm.c
+++ linux-2.6.16-rc2.org/ipc/shm.c
@@ -870,6 +870,7 @@ 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;
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
