Messages in this thread | | | Date | Tue, 6 Dec 2022 23:07:07 +0800 | Subject | Re: [PATCH -next v3] erofs: Fix pcluster memleak when its block address is zero | From | Chao Yu <> |
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On 2022/12/5 14:08, Gao Xiang wrote: > Hi all, > > On Mon, Dec 05, 2022 at 11:49:57AM +0800, Chen Zhongjin wrote: >> 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 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> >> --- >> v1 -> v2: >> As Gao's advice, we should fail to register pcluster if m_pa is zero. >> Maked it this way and changed the commit message. >> >> v2 -> v3: >> Slightly fix commit message and add -next tag. > > I've updated the patch itself as below > (Since we only need to fail out for non-tailpacking cases, tailpacking > inline inodes could still have m_pa < EROFS_BLKSIZ): > > From f5e037e760d338ca0c116e507be663cb843d42f0 Mon Sep 17 00:00:00 2001 > From: Chen Zhongjin <chenzhongjin@huawei.com> > Date: Mon, 5 Dec 2022 11:49:57 +0800 > Subject: [PATCH] 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> > Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Thanks,
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