diff options
| author | Rasmus Villemoes <linux@rasmusvillemoes.dk> | 2013-04-29 15:08:23 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-04-29 15:54:37 -0700 |
| commit | 84d96d897671cfb386e722acbefdb3a79e115a8a (patch) | |
| tree | 0d7559bf9434ccfd933cfd385ff2c3843e6fd396 /mm/madvise.c | |
| parent | 4edd7ceff0662afde195da6f6c43e7cbe1ed2dc4 (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.
[akpm@linux-foundation.org: s/out_plug/out/, per David]
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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/madvise.c')
| -rw-r--r-- | mm/madvise.c | 31 |
1 files changed, 15 insertions, 16 deletions
diff --git a/mm/madvise.c b/mm/madvise.c index c58c94b56c3..7055883e6e2 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 @@ -509,14 +509,14 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior) /* Still start < end. */ error = -ENOMEM; if (!vma) - goto out_plug; + goto out; /* Here start < (end|vma->vm_end). */ if (start < vma->vm_start) { unmapped_error = -ENOMEM; start = vma->vm_start; if (start >= end) - goto out_plug; + goto out; } /* Here vma->vm_start <= start < (end|vma->vm_end) */ @@ -527,21 +527,20 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior) /* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */ error = madvise_vma(vma, &prev, start, tmp, behavior); if (error) - goto out_plug; + goto out; start = tmp; if (prev && start < prev->vm_end) start = prev->vm_end; error = unmapped_error; if (start >= end) - goto out_plug; + goto out; if (prev) vma = prev->vm_next; else /* madvise_remove dropped mmap_sem */ vma = find_vma(current->mm, start); } -out_plug: - blk_finish_plug(&plug); out: + blk_finish_plug(&plug); if (write) up_write(¤t->mm->mmap_sem); else |