On Tue, 20 Jul 2021 at 12:10, Richard Weinberger <richard@xxxxxx> wrote: > > Anyways, I will create a separate thread for dm-verity issue and keep > > this thread still open for UBI image size issue. > > We may use dm-verify for rootfs during booting, but still we need to > > perform integrity check for other nand partitions and UBI volumes. > > > > So, instead of calculating the checksum for the entire partition, is > > it possible to perform checksum only based on the image size ? > > Right now, we are still exploring what are the best possible > > mechanisms available for this. > > I still don't fully understand what you are trying to achieve. > Is it about cryptographic integrity of your storage or detecting > errors after the flashing process? > Yes, it is about md5 checksum verification for every partition to check its integrity before updates. > But let me advertise ubiblock a second time. Sorry, I could not understand about the ubiblock request. Is it possible to elaborate little more ? We are already using squashfs on top of our UBI volumes (including rootfs mounting). This is the kernel command line we pass: rootfstype=squashfs root=/dev/mtdblock44 ubi.mtd=40,0,30 And CONFIG_MTD_UBI_BLOCK=y is already enabled in our kernel. Do we need to do something different for ubiblock ? > If you place your squashfs on a UBI static volume, UBI knows the exact length and you can checksum it > more easily. Yes, we use squashfs on UBI volumes, but our volume type is still dynamic. Also, you said, UBI knows the exact length, you mean the whole image length ? How can we get this length at runtime ? Also, how can we get the checksum of the entire UBI volume content (ignoring the erased/empty/bad block content) ? Or, you mean to say, the whole checksum logic is in-built inside the UBI layer and users don't need to worry about the integrity at all ? Thanks, Pintu
