[PATCH v2 2/4] bootm: Add a bootm command for type IH_OS_EFI

Heinrich Schuchardt xypron.glpk at gmx.de
Wed Dec 11 10:57:48 CET 2019


On 12/11/19 9:54 AM, Cristian Ciocaltea wrote:
> On Tue, Dec 10, 2019 at 08:32:17PM +0100, Heinrich Schuchardt wrote:
>> On 12/10/19 9:56 AM, Cristian Ciocaltea wrote:
>>> Add support for booting EFI binaries contained in FIT images.
>>> A typical usage scenario is chain-loading GRUB2 in a verified
>>> boot environment.
>>>
>>> Signed-off-by: Cristian Ciocaltea<cristian.ciocaltea at gmail.com>
>>
>> Reading through the code it looks good. What I really need to do is
>> analyze the address usage on the sandbox. To me it is unclear if
>> images->fdt_addr is a physical address or an address in the address
>> space of the sandbox.
>>
>> Did you test this on the sandbox? You can use
>> lib/efi_loader/helloworld.efi as a binary and the 'host load hostfs'
>> command for loading the FIT image.
>
> I only tested on qemu, I've never used the sandbox, so it's a good
> opportunity to give it a try.
>
>> Shouldn't we add booting a UEFI FIT image to the Python test in
>> test/py/tests/test_fit.py?
>
> Unfortunately I'm not familiar with the testing framework (including
> Python scripting), but I'll do my best to add such a test.
>
>> doc/uImage.FIT/signature.txt describes that several properties of the
>> RSA public key should be stored in the control device tree.
>> Unfortunately no example is supplied in which format they should be
>> stored. Could you send me an example, please.
>>
>> I found the following
>>
>> https://github.com/bn121rajesh/ipython-notebooks/blob/master/BehindTheScene/RSAPublicKeyParamsUBoot/rsa_public_key_params_uboot.ipynb
>>
>> Is this an accurate description? Or how do you get the parameters from
>> your RSA public key?
>
> My test scenario involves the following steps:
>
> 1. Create a public/private key pair
> $ openssl genpkey -algorithm RSA -out ${DEV_KEY} \
>          -pkeyopt rsa_keygen_bits:2048 -pkeyopt rsa_keygen_pubexp:65537
>
> 2. Create a certificate containing the public key
> $ openssl req -batch -new -x509 -key ${DEV_KEY} -out ${DEV_CRT}
>
> 3. Dump QEMU virt board DTB
> $ qemu-system-arm -nographic -M virt,dumpdtb=${BOARD_DTB} \
>          -cpu cortex-a15 -smp 1 -m 512 -bios u-boot.bin [...]
>
> 4. Create (unsigned) FIT image and put the public key into DTB, with
>     the 'required' property set, telling U-Boot that this key MUST be
>     verified for the image to be valid
> $ mkimage -f ${FIT_ITS} -K ${BOARD_DTB} -k ${KEYS_DIR} -r ${FIT_IMG}
>
> 5. Sign the FIT image
> $ fit_check_sign -f ${FIT_IMG} -k ${BOARD_DTB}
>
> 6. Run QEMU supplying the DTB containing the public key and the
>     u-boot binary built with CONFIG_OF_BOARD
> $ qemu-system-arm -nographic \
>      -M virt -cpu cortex-a15 -smp 1 -m 512 -bios u-boot.bin \
>      -dtb ${BOARD_DTB} [...]
>
> This is what I get after booting QEMU with the command above:
>
> => fdt addr $fdtcontroladdr
> => fdt print
> / {
>      [...]
> 	signature {
> 		key-dev {
> 			required = "conf";
> 			algo = "sha256,rsa2048";
> 			rsa,r-squared = * 0x5ef05188 [0x00000100];
> 			rsa,modulus = * 0x5ef05294 [0x00000100];
> 			rsa,exponent = <0x00000000 0x00010001>;
> 			rsa,n0-inverse = <0x649cd557>;
> 			rsa,num-bits = <0x00000800>;
> 			key-name-hint = "dev";
> 		};
> 	};
>      [...]

See my patch

doc: fitImage: example of a signature node
https://lists.denx.de/pipermail/u-boot/2019-December/393613.html

---

Booting of the sandbox fails due to an incorrect address passed for the
device tree:

=> host load hostfs - $kernel_addr_r image.fit
26558 bytes read in 0 ms
=> bootm ${kernel_addr_r}#config-grub-fdt
## Loading kernel from FIT Image at 01000000 ...
    Using 'config-grub-fdt' configuration
    Verifying Hash Integrity ... OK
    Trying 'helloworld' kernel subimage
      Description:  Hello World
      Created:      2019-12-11   9:19:22 UTC
      Type:         Kernel Image (no loading done)
      Compression:  uncompressed
      Data Start:   0x010000cc
      Data Size:    2733 Bytes = 2.7 KiB
      Hash algo:    sha256
      Hash value:
5c3ba35a1cb4abfe8a867ea6ac709574535794a7d7d03ba1ec2273b956d13983
    Verifying Hash Integrity ... sha256+ OK
    XIP Kernel Image (no loading done)
## Loading fdt from FIT Image at 01000000 ...
    Using 'config-grub-fdt' configuration
    Verifying Hash Integrity ... OK
    Trying 'fdt-test' fdt subimage
      Description:  QEMU DTB
      Created:      2019-12-11   9:19:22 UTC
      Type:         Flat Device Tree
      Compression:  uncompressed
      Data Start:   0x01000c74
      Data Size:    19713 Bytes = 19.3 KiB
      Architecture: ARM
      Hash algo:    sha256
      Hash value:
3e4f4e2b512f7a03a7f9ccecfb2b6bf7ceea75882370639460fd61502d903cd1
    Verifying Hash Integrity ... sha256+ OK
    Booting using the fdt blob at 0x1000c74
Found 0 disks
phys_to_virt: Cannot map sandbox address 11001c74 (SDRAM from 0 to 8000000)
Aborted

Please, check both the FDT and the non-FDT case on the sandbox and
resubmit the patch.

Best regards

Heinrich


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