[U-Boot] [Bug & Question] ubifs does not understand ".." in file path ?

[Heiko Schocher]

Hello Masahiro,

Am 13.07.2018 um 06:44 schrieb Masahiro Yamada:
> Hi.
> 
> 
> I was playing around with the ditro-boot on NAND + UBI.
> 
> I was hit by a problem when loading files from ubifs.
> 
> 
> My 'extlinux.conf' script looks like this:
> 
> ---------------------------------
> menu title UniPhier Boot Options.
> 
> timeout 5
> 
> default UniPhier
> 
> label UniPhier
>        kernel ../Image
>        initrd ../rootfs.cpio.gz
>        fdtdir ..
> ----------------------------------
> 
> 
> As doc/README.distro says,
> 'extlinux.conf' is generally located in 'extlinux' subdirectory.
> 
> So, the paths to kernel, initrd, fdt usually contain '..'
> 
> This totally works fine when loading files
> from a FAT-formated MMC device.
> 
> 'run bootcmd_mmc0' successfully boots Linus
> in the disto-boot manner.
> 
> 
> 
> However, 'run bootcmd_ubifs0' fails to boot.
> 
> 
> => run bootcmd_ubifs0
> ubi0: attaching mtd1
> ubi0: scanning is finished
> ubi0: attached mtd1 (name "mtd=1", size 1023 MiB)
> ubi0: PEB size: 262144 bytes (256 KiB), LEB size: 253952 bytes
> ubi0: min./max. I/O unit sizes: 4096/4096, sub-page size 4096
> ubi0: VID header offset: 4096 (aligned 4096), data offset: 8192
> ubi0: good PEBs: 4088, bad PEBs: 4, corrupted PEBs: 0
> ubi0: user volume: 1, internal volumes: 1, max. volumes count: 128
> ubi0: max/mean erase counter: 1/0, WL threshold: 4096, image sequence
> number: 1407739552
> ubi0: available PEBs: 0, total reserved PEBs: 4088, PEBs reserved for
> bad PEB handling: 76
> UBIFS (ubi0:0): UBIFS: mounted UBI device 0, volume 0, name "boot", R/O mode
> UBIFS (ubi0:0): LEB size: 253952 bytes (248 KiB), min./max. I/O unit
> sizes: 4096 bytes/4096 bytes
> UBIFS (ubi0:0): FS size: 1014284288 bytes (967 MiB, 3994 LEBs),
> journal size 33521664 bytes (31 MiB, 132 LEBs)
> UBIFS (ubi0:0): reserved for root: 4952683 bytes (4836 KiB)
> UBIFS (ubi0:0): media format: w5/r0 (latest is w4/r0), UUID
> cc8f68da-030d-408c-a91f-f8cc195a2946, small LPT model
> Scanning ubi 0:...
> Found /boot/extlinux/extlinux.conf
> Retrieving file: /boot/extlinux/extlinux.conf
> 148 bytes read in 1 ms (144.5 KiB/s)
> UniPhier Boot Options.
> 1:      UniPhier
> Enter choice: 1:        UniPhier
> Retrieving file: /boot/extlinux/../rootfs.cpio.gz
> Skipping UniPhier for failure retrieving initrd
> SCRIPT FAILED: continuing...
> 
> 
> 
> 
> The boot log says
> it succeeded in loading '/boot/extlinux/extlinux.conf'
> but failed in loading '/boot/extlinux/../rootfs.cpio.gz'
> 
> 
> 
> In my quick experiments,
> 
> load '/boot/extlinux/extlinux.conf'            -> SUCCESS
> load '/boot/extlinux/../rootfs.cpio.gz'        -> FAILURE
> load '/boot/rootfs.cpio.gz'                    -> SUCCESS
> load '/boot/extlinux/../Image'                 -> FAILURE
> load '/boot/Image'                             -> SUCCESS
> load '/boot/extlinux/../uniphier-ld20-ref.dtb' -> FAILURE
> load '/boot/uniphier-ld20-ref.dtb'             -> SUCCESS
> 
> 
> 
>  From the test results above,
> my conclusion is loading a file path that contains '..' is not working.
> 
> 
> Not sure where the root cause is.
> Anybody who has insight about this?

No idea, need to try it, but may

fs/ubifs/ubifs.c ubifs_findfile() has a problem with ".." ?

bye,
Heiko
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