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more bio_map_user_iov() leak fixes 

commit 2b04e8f6bb upstream.

we need to take care of failure exit as well - pages already
in bio should be dropped by analogue of bio_unmap_pages(),
since their refcounts had been bumped only once per reference
in bio.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Al Viro 2017-09-23 15:51:23 -04:00 committed by Greg Kroah-Hartman
parent 3a620404e2
commit 047a7bb12d
1 changed files with 9 additions and 5 deletions
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14
block/bio.c
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@ -1268,6 +1268,7 @@ struct bio *bio_map_user_iov(struct request_queue *q,
int ret, offset;
struct iov_iter i;
struct iovec iov;
struct bio_vec *bvec;
iov_for_each(iov, i, *iter) {
unsigned long uaddr = (unsigned long) iov.iov_base;
@ -1312,7 +1313,12 @@ struct bio *bio_map_user_iov(struct request_queue *q,
ret = get_user_pages_fast(uaddr, local_nr_pages,
(iter->type & WRITE) != WRITE,
&pages[cur_page]);
if (ret < local_nr_pages) {
if (unlikely(ret < local_nr_pages)) {
for (j = cur_page; j < page_limit; j++) {
if (!pages[j])
break;
put_page(pages[j]);
}
ret = -EFAULT;
goto out_unmap;
}
@ -1374,10 +1380,8 @@ struct bio *bio_map_user_iov(struct request_queue *q,
return bio;
out_unmap:
for (j = 0; j < nr_pages; j++) {
if (!pages[j])
break;
page_cache_release(pages[j]);
bio_for_each_segment_all(bvec, bio, j) {
put_page(bvec->bv_page);
}
out:
kfree(pages);