From 899f0429c7d3eed886406cd72182bee3b96aa1f9 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Mon, 9 Oct 2017 11:13:18 +0200 Subject: direct-io: Prevent NULL pointer access in submit_page_section In the code added to function submit_page_section by commit b1058b981, sdio->bio can currently be NULL when calling dio_bio_submit. This then leads to a NULL pointer access in dio_bio_submit, so check for a NULL bio in submit_page_section before trying to submit it instead. Fixes xfstest generic/250 on gfs2. Cc: stable@vger.kernel.org # v3.10+ Signed-off-by: Andreas Gruenbacher Reviewed-by: Jan Kara Signed-off-by: Al Viro --- fs/direct-io.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/direct-io.c b/fs/direct-io.c index 62cf812ed0e5..96415c65bbdc 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -866,7 +866,8 @@ out: */ if (sdio->boundary) { ret = dio_send_cur_page(dio, sdio, map_bh); - dio_bio_submit(dio, sdio); + if (sdio->bio) + dio_bio_submit(dio, sdio); put_page(sdio->cur_page); sdio->cur_page = NULL; } -- cgit From 95d78c28b5a85bacbc29b8dba7c04babb9b0d467 Mon Sep 17 00:00:00 2001 From: Vitaly Mayatskikh Date: Fri, 22 Sep 2017 01:18:39 -0400 Subject: fix unbalanced page refcounting in bio_map_user_iov bio_map_user_iov and bio_unmap_user do unbalanced pages refcounting if IO vector has small consecutive buffers belonging to the same page. bio_add_pc_page merges them into one, but the page reference is never dropped. Cc: stable@vger.kernel.org Signed-off-by: Vitaly Mayatskikh Signed-off-by: Al Viro --- block/bio.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/block/bio.c b/block/bio.c index b38e962fa83e..0d6439e89acb 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1383,6 +1383,7 @@ struct bio *bio_map_user_iov(struct request_queue *q, offset = offset_in_page(uaddr); for (j = cur_page; j < page_limit; j++) { unsigned int bytes = PAGE_SIZE - offset; + unsigned short prev_bi_vcnt = bio->bi_vcnt; if (len <= 0) break; @@ -1397,6 +1398,13 @@ struct bio *bio_map_user_iov(struct request_queue *q, bytes) break; + /* + * check if vector was merged with previous + * drop page reference if needed + */ + if (bio->bi_vcnt == prev_bi_vcnt) + put_page(pages[j]); + len -= bytes; offset = 0; } -- cgit From 2b04e8f6bbb196cab4b232af0f8d48ff2c7a8058 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 23 Sep 2017 15:51:23 -0400 Subject: 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 --- block/bio.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/block/bio.c b/block/bio.c index 0d6439e89acb..9e9606d26cc6 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1331,6 +1331,7 @@ 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; @@ -1375,7 +1376,12 @@ 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; } @@ -1431,10 +1437,8 @@ 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; - put_page(pages[j]); + bio_for_each_segment_all(bvec, bio, j) { + put_page(bvec->bv_page); } out: kfree(pages); -- cgit From 1cfd0ddd82232804e03f3023f6a58b50dfef0574 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 24 Sep 2017 10:21:15 -0400 Subject: bio_copy_user_iov(): don't ignore ->iov_offset Since "block: support large requests in blk_rq_map_user_iov" we started to call it with partially drained iter; that works fine on the write side, but reads create a copy of iter for completion time. And that needs to take the possibility of ->iov_iter != 0 into account... Cc: stable@vger.kernel.org #v4.5+ Signed-off-by: Al Viro --- block/bio.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/block/bio.c b/block/bio.c index 9e9606d26cc6..101c2a9b5481 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1239,8 +1239,8 @@ struct bio *bio_copy_user_iov(struct request_queue *q, */ bmd->is_our_pages = map_data ? 0 : 1; memcpy(bmd->iov, iter->iov, sizeof(struct iovec) * iter->nr_segs); - iov_iter_init(&bmd->iter, iter->type, bmd->iov, - iter->nr_segs, iter->count); + bmd->iter = *iter; + bmd->iter.iov = bmd->iov; ret = -ENOMEM; bio = bio_kmalloc(gfp_mask, nr_pages); -- cgit