erofs: validate the extent length for uncompressed pclusters

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[ Upstream commit c505feba4c ]

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: 02827e1796 ("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>

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Gao Xiang 2022-12-05 23:00:50 +08:00 • committed by Greg Kroah-Hartman

parent 373b6f350a

commit 40c73b2ea9

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fs/erofs/zmap.c

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