linux-kernel - Re: [PATCH V5] loop: Add sanity check for read/write

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250520030051.177205-1-lizhi.xu@windriver.com>
Date: Tue, 20 May 2025 11:00:51 +0800
From: Lizhi Xu <lizhi.xu@...driver.com>
To: <mail@...rm.de>
CC: <axboe@...nel.dk>, <christian@...sel.eu>, <hch@...radead.org>,
        <linux-block@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <lizhi.xu@...driver.com>, <ming.lei@...hat.com>,
        <syzbot+6af973a3b8dfd2faefdc@...kaller.appspotmail.com>,
        <syzkaller-bugs@...glegroups.com>
Subject: Re: [PATCH V5] loop: Add sanity check for read/write_iter

On Mon, 19 May 2025 17:56:40 +0200, Christian Hesse wrote:
> $ losetup --find --show --read-only -- /run/archiso/bootmnt/arch/x86_64/airootfs.sfs
> losetup: /run/archiso/bootmnt/arch/x86_64/airootfs.sfs: failed to set up loop device: Invalid argument
I tried to reproduce the problem you mentioned using the kernel containing
"commit:f5c84eff", but failed to reproduce it.
The complete reproduction steps are as follows:

sudo apt install squashfs-tools debootstrap
sudo debootstrap --arch=amd64 focal rootfs http://archive.ubuntu.com/ubuntu/
sudo mksquashfs rootfs rootfs.sfs -comp xz -e boot
root@...el-x86-64:~# losetup --find --show --read-only -- rootfs.sfs
[   79.676267][ T9551] loop0: detected capacity change from 0 to 272400
/dev/loop0
root@...el-x86-64:~# uname -a
Linux intel-x86-64 6.15.0-rc7 #108 SMP PREEMPT_DYNAMIC Mon May 19 09:20:25 CST 2025 x86_64 x86_64 x86_64 GNU/Linux
root@...el-x86-64:~# df -Th
Filesystem     Type      Size  Used Avail Use% Mounted on
/dev/root      ext4      3.8G  738M  2.9G  21% /
devtmpfs       devtmpfs  1.5G     0  1.5G   0% /dev
tmpfs          tmpfs     1.5G     0  1.5G   0% /dev/shm
tmpfs          tmpfs     585M   13M  572M   3% /run
tmpfs          tmpfs     4.0M     0  4.0M   0% /sys/fs/cgroup
tmpfs          tmpfs     1.5G     0  1.5G   0% /tmp
tmpfs          tmpfs     1.5G  904K  1.5G   1% /var/volatile
tmpfs          tmpfs     293M     0  293M   0% /run/user/0
root@...el-x86-64:~# ls -lath /dev/loop0
brw-rw---- 1 root disk 7, 0 May 20 02:43 /dev/loop0
root@...el-x86-64:~# mkdir sfs
root@...el-x86-64:~# mount /dev/loop0 sfs
mount: /root/sfs: WARNING: source write-protected, mounted read-only.
root@...el-x86-64:~# df -Th
Filesystem     Type      Size  Used Avail Use% Mounted on
/dev/root      ext4      3.8G  738M  2.9G  21% /
devtmpfs       devtmpfs  1.5G     0  1.5G   0% /dev
tmpfs          tmpfs     1.5G     0  1.5G   0% /dev/shm
tmpfs          tmpfs     585M   13M  572M   3% /run
tmpfs          tmpfs     4.0M     0  4.0M   0% /sys/fs/cgroup
tmpfs          tmpfs     1.5G     0  1.5G   0% /tmp
tmpfs          tmpfs     1.5G  904K  1.5G   1% /var/volatile
tmpfs          tmpfs     293M     0  293M   0% /run/user/0
/dev/loop0     squashfs  134M  134M     0 100% /root/sfs
root@...el-x86-64:~# ls -alt sfs
total 3
drwx------ 21 root root 3072 May 20 02:49 ..
drwxr-xr-x 16 root root  284 May 20 02:20 .
drwxrwxrwt  2 root root    3 May 20 02:20 tmp
drwxr-xr-x 59 root root 2073 May 20 02:20 etc
drwxr-xr-x  8 root root  124 May 20 02:20 run
drwxr-xr-x  2 root root    3 May 20 02:19 media
drwxr-xr-x  2 root root    3 May 20 02:19 mnt
drwxr-xr-x  2 root root    3 May 20 02:19 opt
drwx------  2 root root   46 May 20 02:19 root
drwxr-xr-x  2 root root    3 May 20 02:19 srv
drwxr-xr-x 13 root root  178 May 20 02:19 usr
drwxr-xr-x 11 root root  172 May 20 02:19 var
drwxr-xr-x  4 root root  191 May 20 02:19 dev
lrwxrwxrwx  1 root root    7 May 20 02:19 bin -> usr/bin
lrwxrwxrwx  1 root root    7 May 20 02:19 lib -> usr/lib
lrwxrwxrwx  1 root root    9 May 20 02:19 lib32 -> usr/lib32
lrwxrwxrwx  1 root root    9 May 20 02:19 lib64 -> usr/lib64
lrwxrwxrwx  1 root root   10 May 20 02:19 libx32 -> usr/libx32
lrwxrwxrwx  1 root root    8 May 20 02:19 sbin -> usr/sbin
drwxr-xr-x  2 root root    3 Apr 15  2020 home
drwxr-xr-x  2 root root    3 Apr 15  2020 proc
drwxr-xr-x  2 root root    3 Apr 15  2020 sys