From: Chen Zhongjin chenzhongjin@huawei.com
[ Upstream commit c42c0ffe81176940bd5dead474216b7198d77675 ]
syzkaller reported a memleak: https://syzkaller.appspot.com/bug?id=62f37ff612f0021641eda5b17f056f1668aa9ae...
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 Signed-off-by: Sasha Levin sashal@kernel.org --- fs/erofs/zdata.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index c7511b431776..f19875d96cc1 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -487,7 +487,8 @@ 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; }