Kernel 4.14: Using dm-verity with squashfs rootfs - mounting issue
thomas.petazzoni at bootlin.com
Mon Aug 30 12:55:41 EDT 2021
On Mon, 30 Aug 2021 21:55:19 +0530
Pintu Agarwal <pintu.ping at gmail.com> wrote:
> Sorry for coming back to this again..
> Unfortunately, none of the options is working for us with squashfs
> (bootloader, initramfs).
> initramfs have different kinds of challenges because of the partition
> size issue.
> So, our preferred option is still the bootloader command line approach..
> Is there a proven and working solution of dm-verity with squashfs ?
> If yes, please share some references.
> The current problem with squashfs is that we could not append the
> verity-metadata to squashfs, so we store it on a separate volume and
> access it.
Here, it definitely worked to append the hash tree to the squashfs
image and store them in the same partition.
> By specifying it like : /dev/mtdblock53
> Then we get the error like this:
> [ 4.950276] device-mapper: init: attempting early device configuration.
> [ 4.957577] device-mapper: init: adding target '0 95384 verity 1
> /dev/ubiblock0_0 /dev/mtdblock53 4096 4096 11923 8 sha256
> aee087a5be3b982978c923f566a94613496b417f2af592639bc80d141e34dfe7 10
> restart_on_corruption ignore_zero_blocks use_fec_from_device
> /dev/mtdblock53 fec_roots 2 fec_blocks 12026 fec_start 12026'
> [ 4.975283] device-mapper: verity: sha256 using implementation
> [ 4.998728] device-mapper: init: dm-0 is ready
Could you show the full kernel command line ?
> Do you see any other problem here with dm-verity cmdline or with squashfs ?
> Is squashfs ever proved to be working with dm-verity on higher kernel version ?
> Currently our kernel version is 4.14.
I confirm we used squashfs on dm-verity successfully. For sure on 4.19,
perhaps on older kernels as well.
> Or, another option is to use the new concept from 5.1 kernel that is:
> dm-mod.create = ?
How are you doing it today without dm-mod.create ?
Again, please give your complete kernel command line.
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering
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