This series implemented a verified boot system based around FIT images as discussed on the U-Boot mailing list, including on this thread:
http://permalink.gmane.org/gmane.comp.boot-loaders.u-boot/147830
RSA is used to implement the encryption. Images are signed by mkimage using private keys created by the user. Public keys are written into U-Boot control FDT (CONFIG_OF_CONTROL) for access by bootm etc. at run-time. The control FDT must be stored in a secure place where it cannot be changed after manufacture. Some notes are provided in the documentaion on how this can be achieved.
When images are loaded, they are verified with the public keys.
Some minor restructuring of the image code is included in this series, since we now support signatures as well as hashes.
It is important to have a test framework for this series. For this, sandbox is used, and a script is provided which signs images and gets sandbox to load them using a script, to check that all is well. So some of the patches here release to adding image support for sandbox.
This series is not quite in final form since it still needs rollback support, using a TPM or some other mechanism to make sure that an attacker cannot boot your system with an old image that has been compromised.
Also a few more tests are needed to check that image corruption has the desired effect, some proofreading is required, another review of error checking, etc.
This series relies on two previous series: sandbox filesystem and sandbox memory. Without these, it is (at best) not possible to run the verified boot test on sandbox.
This series and its dependencies are available at:
http://git.denx.de/u-boot-x86.git
in the branch 'vboot'.
Comments welcome.
Simon Glass (44): sandbox: config: Enable CONFIG_FIT and CONFIG_CMD_FIT bootstage: Don't build for HOSTCC mkimage: Move ARRAY_SIZE to header file libfdt: Add fdt_next_subnode() to permit easy subnode iteration image: Move timestamp #ifdefs to header file image: Export fit_check_ramdisk() image: Split FIT code into new image-fit.c image: Move HOSTCC image code to tools/ image: Split hash node processing into its own function image: Convert fit_image_hash_set_value() to static, and rename image: Rename fit_image_check_hashes() to fit_image_verify() image: Move hash checking into its own functions image: Move error! string to common place image: Export fit_conf_get_prop_node() image: Rename fit_add_hashes() to fit_add_verification_data() image: Rename hash printing to fit_image_print_verification_data() sandbox: Add CONFIG_OF_HOSTFILE to read FDT from host file fdt: Add a parameter to fdt_valid() Add getenv_hex() to return an environment variable as hex fdt: Allow fdt command to check and update control FDT sandbox: fdt: Support fdt command for sandbox env: Fix minor comment typos in cmd_nvedit fdt: Skip checking FDT if the pointer is NULL Revert "fdt- Tell the FDT library where the device tree is" Add stdarg to vsprintf.h Add minor updates to README.fdt-control hash: Add a way to calculate a hash for any algortihm sandbox: config: Enable FIT signatures with RSA sandbox: Provide a way to map from host RAM to U-Boot RAM sandbox: image: Add support for booting images in sandbox image: Add signing infrastructure image: Support signing of images image: Verify signatures in FIT images image: Add RSA support for image signing mkimage: Put FIT loading in function and tidy error handling mkimage: Add -k option to specify key directory mkimage: Add -K to write public keys to an FDT blob mkimage: Add -F option to modify an existing .fit file mkimage: Add -c option to specify a comment for key signing mkimage: Add -r option to specify keys that must be verified libfdt: Add fdt_find_regions() image: Add support for signing of FIT configurations Add verified boot information and test WIP: sandbox: config: Add test config for verified boot
Makefile | 1 + README | 15 + arch/sandbox/cpu/cpu.c | 5 + arch/sandbox/cpu/start.c | 7 + arch/sandbox/include/asm/io.h | 2 + arch/sandbox/include/asm/state.h | 1 + arch/sandbox/lib/board.c | 42 +- common/Makefile | 2 + common/cmd_bootm.c | 37 +- common/cmd_fdt.c | 83 ++- common/cmd_fpga.c | 2 +- common/cmd_nvedit.c | 19 +- common/cmd_source.c | 2 +- common/cmd_ximg.c | 2 +- common/hash.c | 22 + common/image-fit.c | 1544 +++++++++++++++++++++++++++++++++++ common/image-sig.c | 407 +++++++++ common/image.c | 1677 +------------------------------------- common/main.c | 8 - common/update.c | 2 +- config.mk | 1 + doc/README.fdt-control | 13 +- doc/mkimage.1 | 73 ++- doc/uImage.FIT/sign-configs.its | 45 + doc/uImage.FIT/sign-images.its | 42 + doc/uImage.FIT/signature.txt | 376 +++++++++ doc/uImage.FIT/verified-boot.txt | 104 +++ include/bootstage.h | 5 +- include/common.h | 18 + include/configs/sandbox.h | 20 +- include/hash.h | 15 + include/image.h | 213 +++++- include/libfdt.h | 81 ++ include/rsa.h | 108 +++ include/vsprintf.h | 2 + lib/fdtdec.c | 3 +- lib/libfdt/fdt.c | 12 + lib/libfdt/fdt_wip.c | 129 +++ lib/rsa/Makefile | 46 + lib/rsa/rsa-sign.c | 454 +++++++++++ lib/rsa/rsa-verify.c | 374 +++++++++ test/vboot/.gitignore | 3 + test/vboot/sandbox-kernel.dts | 7 + test/vboot/sandbox-u-boot.dts | 7 + test/vboot/sign-configs.its | 45 + test/vboot/sign-images.its | 42 + test/vboot/vboot_test.sh | 122 +++ tools/Makefile | 21 +- tools/aisimage.c | 1 - tools/fit_image.c | 134 ++- tools/image-host.c | 727 +++++++++++++++++ tools/mkimage.c | 27 +- tools/mkimage.h | 6 + 53 files changed, 5386 insertions(+), 1770 deletions(-) create mode 100644 common/image-fit.c create mode 100644 common/image-sig.c create mode 100644 doc/uImage.FIT/sign-configs.its create mode 100644 doc/uImage.FIT/sign-images.its create mode 100644 doc/uImage.FIT/signature.txt create mode 100644 doc/uImage.FIT/verified-boot.txt create mode 100644 include/rsa.h create mode 100644 lib/rsa/Makefile create mode 100644 lib/rsa/rsa-sign.c create mode 100644 lib/rsa/rsa-verify.c create mode 100644 test/vboot/.gitignore create mode 100644 test/vboot/sandbox-kernel.dts create mode 100644 test/vboot/sandbox-u-boot.dts create mode 100644 test/vboot/sign-configs.its create mode 100644 test/vboot/sign-images.its create mode 100755 test/vboot/vboot_test.sh create mode 100644 tools/image-host.c