linux/fs/erofs
Chen Zhongjin c42c0ffe81 erofs: Fix pcluster memleak when its block address is zero
syzkaller reported a memleak:
https://syzkaller.appspot.com/bug?id=62f37ff612f0021641eda5b17f056f1668aa9aed

unreferenced object 0xffff88811009c7f8 (size 136):
  ...
  backtrace:
    [<ffffffff821db19b>] z_erofs_do_read_page+0x99b/0x1740
    [<ffffffff821dee9e>] z_erofs_readahead+0x24e/0x580
    [<ffffffff814bc0d6>] read_pages+0x86/0x3d0
    ...

syzkaller constructed a case: in z_erofs_register_pcluster(),
ztailpacking = false and map->m_pa = zero. This makes pcl->obj.index be
zero although pcl is not a inline pcluster.

Then following path adds refcount for grp, but the refcount won't be put
because pcl is inline.

z_erofs_readahead()
  z_erofs_do_read_page() # for another page
    z_erofs_collector_begin()
      erofs_find_workgroup()
        erofs_workgroup_get()

Since it's illegal for the block address of a non-inlined pcluster to
be zero, add check here to avoid registering the pcluster which would
be leaked.

Fixes: cecf864d3d ("erofs: support inline data decompression")
Reported-by: syzbot+6f8cd9a0155b366d227f@syzkaller.appspotmail.com
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/Y42Kz6sVkf+XqJRB@debian
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2022-12-07 10:56:31 +08:00
..
compress.h erofs: introduce multi-reference pclusters (fully-referenced) 2022-07-22 21:44:27 +08:00
data.c erofs: use kmap_local_page() only for erofs_bread() 2022-12-07 10:56:31 +08:00
decompressor_lzma.c erofs: introduce partial-referenced pclusters 2022-09-26 23:55:43 +08:00
decompressor.c erofs: support interlaced uncompressed data for compressed files 2022-09-23 10:55:56 +08:00
dir.c erofs: update ctx->pos for every emitted dirent 2022-07-31 22:26:29 +08:00
erofs_fs.h erofs: introduce partial-referenced pclusters 2022-09-26 23:55:43 +08:00
fscache.c erofs: support large folios for fscache mode 2022-12-07 10:56:30 +08:00
inode.c erofs: use kmap_local_page() only for erofs_bread() 2022-12-07 10:56:31 +08:00
internal.h erofs: use kmap_local_page() only for erofs_bread() 2022-12-07 10:56:31 +08:00
Kconfig erofs: register fscache volume 2022-05-18 00:11:19 +08:00
Makefile erofs: register fscache volume 2022-05-18 00:11:19 +08:00
namei.c erofs: clean up erofs_iget() 2022-09-27 17:27:45 +08:00
pcpubuf.c erofs: get rid of ->lru usage 2021-10-25 08:22:59 +08:00
super.c erofs: check the uniqueness of fsid in shared domain in advance 2022-12-07 10:53:40 +08:00
sysfs.c erofs: fix use-after-free of fsid and domain_id string 2022-11-10 09:53:20 +08:00
tagptr.h erofs: clean up file headers & footers 2021-06-08 00:41:24 +08:00
utils.c mm: shrinkers: provide shrinkers with names 2022-07-03 18:08:40 -07:00
xattr.c erofs: use kmap_local_page() only for erofs_bread() 2022-12-07 10:56:31 +08:00
xattr.h erofs: clean up unnecessary code and comments 2022-09-27 17:27:25 +08:00
zdata.c erofs: Fix pcluster memleak when its block address is zero 2022-12-07 10:56:31 +08:00
zdata.h erofs: shouldn't churn the mapping page for duplicated copies 2022-10-17 06:55:49 +08:00
zmap.c erofs: use kmap_local_page() only for erofs_bread() 2022-12-07 10:56:31 +08:00