more bio_map_user_iov() leak fixes

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>
(cherry picked from commit 2b04e8f6bbb196cab4b232af0f8d48ff2c7a8058)

Orabug: 27062562
CVE: CVE-2017-12190

Signed-off-by: Kirtikar Kashyap <kirtikar.kashyap@oracle.com>
Acked-by: Ethan Zhao <ethan.zhao@oracle.com>
Reviewed-by: Shan Hai <shan.hai@oracle.com>
 Conflicts:
	block/bio.c

diff --git a/block/bio.c b/block/bio.c
index 64fe2c25e6760b190c7a1cd2d0401b455c883a14..6e31ceacd4a906000cdfc5efcc20549da47e7952 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -1309,6 +1309,7 @@ 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;
@@ -1353,7 +1354,12 @@ 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;
                }
@@ -1407,10 +1413,8 @@ 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);