Re: mkimage regression when building ARCH=mips defconfig Linux kernel

[Tom Rini <trini@konsulko.com>]

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On Fri, Apr 09, 2021 at 11:55:52AM +1200, Simon Glass wrote:
> +Tom Rini
> 
> Hi Nathan,
> 
> On Fri, 9 Apr 2021 at 06:23, Nathan Chancellor <nathan@kernel.org> wrote:
> >
> > Hi Simon,
> >
> > Apologies if this is not the proper way to report a regression, this is my first
> > time interacting with the U-Boot community.
> >
> > My distribution updated the uboot-tools package to 2021.04, which broke my
> > Linux kernel builds for ARCH=mips:
> >
> > $ make -skj"$(nproc)" ARCH=mips CROSS_COMPILE=mips-linux- defconfig all
> > ...
> > /usr/bin/mkimage: verify_header failed for FIT Image support with exit code 1
> > make[2]: *** [arch/mips/boot/Makefile:173: arch/mips/boot/vmlinux.gz.itb] Error 1
> > ...
> >
> > I bisected this down to your commit:
> >
> > 3f04db891a353f4b127ed57279279f851c6b4917 is the first bad commit
> > commit 3f04db891a353f4b127ed57279279f851c6b4917
> > Author: Simon Glass <sjg@chromium.org>
> > Date:   Mon Feb 15 17:08:12 2021 -0700
> >
> >     image: Check for unit addresses in FITs
> >
> >     Using unit addresses in a FIT is a security risk. Add a check for this
> >     and disallow it.
> >
> >     CVE-2021-27138
> >
> >     Signed-off-by: Simon Glass <sjg@chromium.org>
> >     Reported-by: Bruce Monroe <bruce.monroe@intel.com>
> >     Reported-by: Arie Haenel <arie.haenel@intel.com>
> >     Reported-by: Julien Lenoir <julien.lenoir@intel.com>
> >
> >  common/image-fit.c          | 56 +++++++++++++++++++++++++++++++++++++++++----
> >  test/py/tests/test_vboot.py |  9 ++++----
> >  2 files changed, 57 insertions(+), 8 deletions(-)
> > bisect run success
> >
> > $ git bisect log
> > # bad: [e9c99db7787e3b5c2ef05701177c43ed1c023c27] Merge branch '2021-04-07-CI-improvements'
> > # good: [c4fddedc48f336eabc4ce3f74940e6aa372de18c] Prepare v2021.01
> > git bisect start 'e9c99db7787e3b5c2ef05701177c43ed1c023c27' 'v2021.01'
> > # good: [b2c86f596cfb1ea9f7f5138f72f1c5c49e3ae3f1] arm: dts: r8a774a1: Import DTS queued for Linux 5.12-rc1
> > git bisect good b2c86f596cfb1ea9f7f5138f72f1c5c49e3ae3f1
> > # bad: [74f4929c2c73beb595faf7d5d9bb6a78d710c2fd] ddr: marvell: axp: fix array types have different bounds warning
> > git bisect bad 74f4929c2c73beb595faf7d5d9bb6a78d710c2fd
> > # bad: [cbe607b920bc0827d8fe379ed4f5ae4e2058513e] Merge tag 'xilinx-for-v2021.04-rc3' of https://gitlab.denx.de/u-boot/custodians/u-boot-microblaze
> > git bisect bad cbe607b920bc0827d8fe379ed4f5ae4e2058513e
> > # good: [d5f3aadacbc63df3b690d6fd9f0aa3f575b43356] test: Add tests for the 'evil' vboot attacks
> > git bisect good d5f3aadacbc63df3b690d6fd9f0aa3f575b43356
> > # bad: [a1a652e8016426e2d67148cab225cd5ec45189fb] Merge tag 'mmc-2021-2-19' of https://gitlab.denx.de/u-boot/custodians/u-boot-mmc
> > git bisect bad a1a652e8016426e2d67148cab225cd5ec45189fb
> > # bad: [aeedeae40733131467de72c68e639cf9d795e059] spl: fit: Replace #ifdef blocks with more readable constructs
> > git bisect bad aeedeae40733131467de72c68e639cf9d795e059
> > # bad: [eb5fd9e46c11ea41430d9c5bcc81d4583424216e] usb: kbd: destroy device after console is stopped
> > git bisect bad eb5fd9e46c11ea41430d9c5bcc81d4583424216e
> > # bad: [99cb2b996bd649d98069a95941beaaade0a4447a] stdio: Split out nulldev_register() and move it under #if
> > git bisect bad 99cb2b996bd649d98069a95941beaaade0a4447a
> > # bad: [3f04db891a353f4b127ed57279279f851c6b4917] image: Check for unit addresses in FITs
> > git bisect bad 3f04db891a353f4b127ed57279279f851c6b4917
> > # good: [6f3c2d8aa5e6cbd80b5e869bbbddecb66c329d01] image: Add an option to do a full check of the FIT
> > git bisect good 6f3c2d8aa5e6cbd80b5e869bbbddecb66c329d01
> > # good: [124c255731c76a2b09587378b2bcce561bcd3f2d] libfdt: Check for multiple/invalid root nodes
> > git bisect good 124c255731c76a2b09587378b2bcce561bcd3f2d
> > # first bad commit: [3f04db891a353f4b127ed57279279f851c6b4917] image: Check for unit addresses in FITs
> >
> > Is this an actual regression or is this now the expected behavior? I have added
> > Thomas and the linux-mips mailing list to take a look and see if the Linux
> > kernel needs to have its sources updated.
> 
> It is expected. See the code in that commit:
> 
>       /*
>        * U-Boot stopped using unit addressed in 2017. Since libfdt
>        * can match nodes ignoring any unit address, signature
>        * verification can see the wrong node if one is inserted with
>        * the same name as a valid node but with a unit address
>        * attached. Protect against this by disallowing unit addresses.
>        */
>       if (!ret && CONFIG_IS_ENABLED(FIT_SIGNATURE)) {
>          ret = fdt_check_no_at(fit, 0);
> 
>          if (ret) {
>             log_debug("FIT check error %d\n", ret);
>             return ret;
>          }
>       }
> 
> Possibly you are using @ nodes in your FIT files in the kernel. Is it
> possible to use a hyphen instead?

Yeah, it looks like arch/mips/generic/*.its.S in the kernel will need to
be updated.

-- 
Tom

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