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author | Chen Zhongjin <chenzhongjin@huawei.com> | 2022-12-05 11:49:57 +0800 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-12-31 13:31:59 +0100 |
commit | 618e712b99c78d1004b70a1a9ab0a4830d0b2673 (patch) | |
tree | ed5efbf0edd14960cdf9f8860478524d9ebfcce7 /fs/erofs | |
parent | 18067e262416a2c256645c6a280e86cad370fdf9 (diff) | |
download | linux-618e712b99c78d1004b70a1a9ab0a4830d0b2673.tar.gz |
erofs: Fix pcluster memleak when its block address is zero
[ Upstream commit c42c0ffe81176940bd5dead474216b7198d77675 ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
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 b792d424d774..cf4871834ebb 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -488,7 +488,8 @@ 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; } |