From: Gao Xiang hsiangkao@linux.alibaba.com
[ Upstream commit c505feba4c0d76084e56ec498ce819f02a7043ae ]
syzkaller reported a KASAN use-after-free: https://syzkaller.appspot.com/bug?extid=2ae90e873e97f1faf6f2
The referenced fuzzed image actually has two issues: - m_pa == 0 as a non-inlined pcluster; - The logical length is longer than its physical length.
The first issue has already been addressed. This patch addresses the second issue by checking the extent length validity.
Reported-by: syzbot+2ae90e873e97f1faf6f2@syzkaller.appspotmail.com Fixes: 02827e1796b3 ("staging: erofs: add erofs_map_blocks_iter") Reviewed-by: Chao Yu chao@kernel.org Signed-off-by: Gao Xiang hsiangkao@linux.alibaba.com Link: https://lore.kernel.org/r/20221205150050.47784-2-hsiangkao@linux.alibaba.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/erofs/zmap.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c index a2a44c11bb64..720d74b5c699 100644 --- a/fs/erofs/zmap.c +++ b/fs/erofs/zmap.c @@ -677,6 +677,11 @@ static int z_erofs_do_map_blocks(struct inode *inode, }
if (m.headtype == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN) { + if (map->m_llen > map->m_plen) { + DBG_BUGON(1); + err = -EFSCORRUPTED; + goto unmap_out; + } if (vi->z_advise & Z_EROFS_ADVISE_INTERLACED_PCLUSTER) map->m_algorithmformat = Z_EROFS_COMPRESSION_INTERLACED;