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| author | Chen Zhongjin <chenzhongjin@huawei.com> | 2022-12-05 06:49:57 +0300 |
|---|---|---|
| committer | Gao Xiang <hsiangkao@linux.alibaba.com> | 2022-12-07 05:56:31 +0300 |
| commit | c42c0ffe81176940bd5dead474216b7198d77675 (patch) | |
| tree | e465a4e4fa7597e7a673a46cfcb51df47608e377 /fs/erofs | |
| parent | 927e5010ff5bd7446a22c511ab8643b9385ddf4d (diff) | |
| download | linux-c42c0ffe81176940bd5dead474216b7198d77675.tar.xz | |
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: cecf864d3d76 ("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>
Diffstat (limited to 'fs/erofs')
| -rw-r--r-- | fs/erofs/zdata.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index b66c16473273..ccf7c55d477f 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -496,7 +496,8 @@ static int z_erofs_register_pcluster(struct z_erofs_decompress_frontend *fe) struct erofs_workgroup *grp; int err; - if (!(map->m_flags & EROFS_MAP_ENCODED)) { + if (!(map->m_flags & EROFS_MAP_ENCODED) || + (!ztailpacking && !(map->m_pa >> PAGE_SHIFT))) { DBG_BUGON(1); return -EFSCORRUPTED; } |