diff options
| author | Davidlohr Bueso <davidlohr.bueso@hp.com> | 2013-09-11 14:26:28 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-09-11 15:59:44 -0700 |
| commit | 530fcd16d87cd2417c472a581ba5a1e501556c86 (patch) | |
| tree | c741f07d57e5b6fdf5920c6ba87e59b779073aaf /ipc | |
| parent | 05603c44a7627793219b0bd9a7b236099dc9cd9d (diff) | |
| download | lwn-530fcd16d87cd2417c472a581ba5a1e501556c86.tar.gz lwn-530fcd16d87cd2417c472a581ba5a1e501556c86.zip | |
ipc, shm: guard against non-existant vma in shmdt(2)
When !CONFIG_MMU there's a chance we can derefence a NULL pointer when the
VM area isn't found - check the return value of find_vma().
Also, remove the redundant -EINVAL return: retval is set to the proper
return code and *only* changed to 0, when we actually unmap the segments.
Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'ipc')
| -rw-r--r-- | ipc/shm.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/ipc/shm.c b/ipc/shm.c index cb2cedaa8808..a0ed957cefc9 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -1288,8 +1288,7 @@ SYSCALL_DEFINE1(shmdt, char __user *, shmaddr) #else /* CONFIG_MMU */ /* under NOMMU conditions, the exact address to be destroyed must be * given */ - retval = -EINVAL; - if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) { + if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) { do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); retval = 0; } |