diff options
| author | Rasmus Villemoes <linux@rasmusvillemoes.dk> | 2013-04-18 09:47:14 +1000 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2013-04-23 17:18:00 +1000 |
| commit | 03e7180b41006f514a703d9bacd2b7de65b1b9fc (patch) | |
| tree | 211998d9ee61f3b693af94504adb3b1bd1caae4e /mm | |
| parent | eff2d336d14c81c4b27683ac3defe58aba30263e (diff) | |
mm: madvise: complete input validation before taking lock
In madvise(), there doesn't seem to be any reason for taking the
¤t->mm->mmap_sem before start and len_in have been validated.
Incidentally, this removes the need for the out: label.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/madvise.c | 21 |
1 files changed, 10 insertions, 11 deletions
diff --git a/mm/madvise.c b/mm/madvise.c index c58c94b56c3d..d2ae6682b886 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -473,27 +473,27 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior) if (!madvise_behavior_valid(behavior)) return error; - write = madvise_need_mmap_write(behavior); - if (write) - down_write(¤t->mm->mmap_sem); - else - down_read(¤t->mm->mmap_sem); - if (start & ~PAGE_MASK) - goto out; + return error; len = (len_in + ~PAGE_MASK) & PAGE_MASK; /* Check to see whether len was rounded up from small -ve to zero */ if (len_in && !len) - goto out; + return error; end = start + len; if (end < start) - goto out; + return error; error = 0; if (end == start) - goto out; + return error; + + write = madvise_need_mmap_write(behavior); + if (write) + down_write(¤t->mm->mmap_sem); + else + down_read(¤t->mm->mmap_sem); /* * If the interval [start,end) covers some unmapped address @@ -541,7 +541,6 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior) } out_plug: blk_finish_plug(&plug); -out: if (write) up_write(¤t->mm->mmap_sem); else |