block: don't access bio->bi_error after bio_put()
Commit 4246a0b6 ("block: add a bi_error field to struct bio") has added a few
dereferences of 'bio' after a call to bio_put(). This causes use-after-frees
such as:
[521120.719695] BUG: KASan: use after free in dio_bio_complete+0x2b3/0x320 at addr ffff880f36b38714
[521120.720638] Read of size 4 by task mount.ocfs2/9644
[521120.721212] =============================================================================
[521120.722056] BUG kmalloc-256 (Not tainted): kasan: bad access detected
[521120.722968] -----------------------------------------------------------------------------
[521120.722968]
[521120.723915] Disabling lock debugging due to kernel taint
[521120.724539] INFO: Slab 0xffffea003cdace00 objects=32 used=25 fp=0xffff880f36b38600 flags=0x46fffff80004080
[521120.726037] INFO: Object 0xffff880f36b38700 @offset=1792 fp=0xffff880f36b38800
[521120.726037]
[521120.726974] Bytes b4 ffff880f36b386f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
[521120.727898] Object ffff880f36b38700: 00 88 b3 36 0f 88 ff ff 00 00 d8 de 0b 88 ff ff ...6............
[521120.728822] Object ffff880f36b38710: 02 00 00 f0 00 00 00 00 00 00 00 00 00 00 00 00 ................
[521120.729705] Object ffff880f36b38720: 01 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 ................
[521120.730623] Object ffff880f36b38730: 00 00 00 00 00 00 00 00 01 00 00 00 00 02 00 00 ................
[521120.731621] Object ffff880f36b38740: 00 02 00 00 01 00 00 00 d0 f7 87 ad ff ff ff ff ................
[521120.732776] Object ffff880f36b38750: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
[521120.733640] Object ffff880f36b38760: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
[521120.734508] Object ffff880f36b38770: 01 00 03 00 01 00 00 00 88 87 b3 36 0f 88 ff ff ...........6....
[521120.735385] Object ffff880f36b38780: 00 73 22 ad 02 88 ff ff 40 13 e0 3c 00 ea ff ff .s".....@..<....
[521120.736667] Object ffff880f36b38790: 00 02 00 00 00 04 00 00 00 00 00 00 00 00 00 00 ................
[521120.737596] Object ffff880f36b387a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
[521120.738524] Object ffff880f36b387b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
[521120.739388] Object ffff880f36b387c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
[521120.740277] Object ffff880f36b387d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
[521120.741187] Object ffff880f36b387e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
[521120.742233] Object ffff880f36b387f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
[521120.743229] CPU: 41 PID: 9644 Comm: mount.ocfs2 Tainted: G B 4.2.0-rc6-next-20150810-sasha-00039-gf909086 #2420
[521120.744274] ffff880f36b38000 ffff880d89c8f638 ffffffffb6e9ba8a ffff880101c0e5c0
[521120.745025] ffff880d89c8f668 ffffffffad76a313 ffff880101c0e5c0 ffffea003cdace00
[521120.745908] ffff880f36b38700 ffff880f36b38798 ffff880d89c8f690 ffffffffad772854
[521120.747063] Call Trace:
[521120.747520] dump_stack (lib/dump_stack.c:52)
[521120.748053] print_trailer (mm/slub.c:653)
[521120.748582] object_err (mm/slub.c:660)
[521120.749079] kasan_report_error (include/linux/kasan.h:20 mm/kasan/report.c:152 mm/kasan/report.c:194)
[521120.750834] __asan_report_load4_noabort (mm/kasan/report.c:250)
[521120.753580] dio_bio_complete (fs/direct-io.c:478)
[521120.755752] do_blockdev_direct_IO (fs/direct-io.c:494 fs/direct-io.c:1291)
[521120.759765] __blockdev_direct_IO (fs/direct-io.c:1322)
[521120.761658] blkdev_direct_IO (fs/block_dev.c:162)
[521120.762993] generic_file_read_iter (mm/filemap.c:1738)
[521120.767405] blkdev_read_iter (fs/block_dev.c:1649)
[521120.768556] __vfs_read (fs/read_write.c:423 fs/read_write.c:434)
[521120.772126] vfs_read (fs/read_write.c:454)
[521120.773118] SyS_pread64 (fs/read_write.c:607 fs/read_write.c:594)
[521120.776062] entry_SYSCALL_64_fastpath (arch/x86/entry/entry_64.S:186)
[521120.777375] Memory state around the buggy address:
[521120.778118] ffff880f36b38600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[521120.779211] ffff880f36b38680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[521120.780315] >ffff880f36b38700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[521120.781465] ^
[521120.782083] ffff880f36b38780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[521120.783717] ffff880f36b38800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[521120.784818] ==================================================================
This patch fixes a few of those places that I caught while auditing the patch, but the
original patch should be audited further for more occurences of this issue since I'm
not too familiar with the code.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Sasha Levin
Jens Axboe
parent
2c68f6dc6e
commit
9b81c84235
@ -1102,6 +1102,7 @@ static void crypt_endio(struct bio *clone)
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struct dm_crypt_io *io = clone->bi_private;
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struct crypt_config *cc = io->cc;
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unsigned rw = bio_data_dir(clone);
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int error;
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/*
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* free the processed pages
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@ -1109,15 +1110,16 @@ static void crypt_endio(struct bio *clone)
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if (rw == WRITE)
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crypt_free_buffer_pages(cc, clone);
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error = clone->bi_error;
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bio_put(clone);
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if (rw == READ && !clone->bi_error) {
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if (rw == READ && !error) {
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kcryptd_queue_crypt(io);
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return;
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}
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if (unlikely(clone->bi_error))
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io->error = clone->bi_error;
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if (unlikely(error))
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io->error = error;
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crypt_dec_pending(io);
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}
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@ -138,6 +138,7 @@ static void endio(struct bio *bio)
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{
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struct io *io;
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unsigned region;
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int error;
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if (bio->bi_error && bio_data_dir(bio) == READ)
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zero_fill_bio(bio);
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@ -147,9 +148,10 @@ static void endio(struct bio *bio)
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*/
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retrieve_io_and_region_from_bio(bio, &io, ®ion);
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error = bio->bi_error;
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bio_put(bio);
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dec_count(io, region, bio->bi_error);
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dec_count(io, region, error);
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}
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/*-----------------------------------------------------------------
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@ -4756,6 +4756,7 @@ static void raid5_align_endio(struct bio *bi)
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struct mddev *mddev;
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struct r5conf *conf;
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struct md_rdev *rdev;
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int error = bi->bi_error;
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bio_put(bi);
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@ -4766,7 +4767,7 @@ static void raid5_align_endio(struct bio *bi)
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rdev_dec_pending(rdev, conf->mddev);
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if (!bi->bi_error) {
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if (!error) {
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trace_block_bio_complete(bdev_get_queue(raid_bi->bi_bdev),
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raid_bi, 0);
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bio_endio(raid_bi);
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@ -459,12 +459,14 @@ static int dio_bio_complete(struct dio *dio, struct bio *bio)
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{
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struct bio_vec *bvec;
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unsigned i;
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int err;
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if (bio->bi_error)
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dio->io_error = -EIO;
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if (dio->is_async && dio->rw == READ) {
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bio_check_pages_dirty(bio); /* transfers ownership */
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err = bio->bi_error;
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} else {
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bio_for_each_segment_all(bvec, bio, i) {
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struct page *page = bvec->bv_page;
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@ -473,9 +475,10 @@ static int dio_bio_complete(struct dio *dio, struct bio *bio)
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set_page_dirty_lock(page);
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page_cache_release(page);
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}
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err = bio->bi_error;
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bio_put(bio);
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}
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return bio->bi_error;
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return err;
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}
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/*
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