From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sat, 23 Sep 2017 19:51:23 +0000 (-0400)
Subject: more bio_map_user_iov() leak fixes
X-Git-Tag: v3.2.97~49
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8fab3702764bd73f2f9b8e1c140ef1de845e3071;p=thirdparty%2Fkernel%2Fstable.git

more bio_map_user_iov() leak fixes

commit 2b04e8f6bbb196cab4b232af0f8d48ff2c7a8058 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.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[bwh: Backported to 3.2: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/fs/bio.c b/fs/bio.c
index 1fa6b825240d8..081747c89b627 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -976,6 +976,7 @@ static struct bio *__bio_map_user_iov(struct request_queue *q,
 	struct bio *bio;
 	int cur_page = 0;
 	int ret, offset;
+	struct bio_vec *bvec;
 
 	for (i = 0; i < iov_count; i++) {
 		unsigned long uaddr = (unsigned long)iov[i].iov_base;
@@ -1019,7 +1020,12 @@ static struct bio *__bio_map_user_iov(struct request_queue *q,
 
 		ret = get_user_pages_fast(uaddr, local_nr_pages,
 				write_to_vm, &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;
 		}
@@ -1074,10 +1080,8 @@ static struct bio *__bio_map_user_iov(struct request_queue *q,
 	return bio;
 
  out_unmap:
-	for (i = 0; i < nr_pages; i++) {
-		if(!pages[i])
-			break;
-		page_cache_release(pages[i]);
+	bio_for_each_segment_all(bvec, bio, j) {
+		put_page(bvec->bv_page);
 	}
  out:
 	kfree(pages);