For those that have asked me about this, I have dug into the past and cannot find my experiment. In the end I managed to reduce U-Boot proper down to about 100KB of code (by dropping CONFIG_CMD and removing video and USB drivers) and this was small enough to fit in SRAM. So SPL was not needed.
That said, my experiment drove a lot of the FIT and image refactoring and I think it is actually pretty easy now to enable the full FIT implementation in SPL, if your SoC limitations allow it.
In the case of Chrome OS, both U-Boot SPL and U-Boot proper are in read-only memory so there is no need for this. But even then it is useful to be able to have the smallest amount of non-updateable software, so quite a bit of work was done (for pit/pi) to support loading a read-write 'U-Boot proper' from SPL.
So I think it would be useful to support loading and verifying FIT images with public key encryption in U-Boot, and fairly straightforward.
To help things along, here is a starting point for firefly-rk3288 (Thumb 2). This board already uses device tree in SPL (perhaps bravely given the SoC size limitations) so the additional code would be a few KB larger for platforms that don't.
For firefly the code size increases from 26KB to 40 KB. There is a fair bit of opportunity to reduce this if needed, for example by cutting out strings.
Please reply on this thread if you plan to pick this up and prepare a series to enable this in U-Boot, to reduce duplicated work. Signed-off-by: Simon Glass sjg@chromium.org ---
Kconfig | 8 ++++++++ common/Makefile | 3 ++- common/image-fit.c | 2 +- common/spl/spl.c | 1 + configs/firefly-rk3288_defconfig | 5 +++++ drivers/Makefile | 1 + include/configs/rk3288_common.h | 2 ++ lib/Makefile | 3 ++- lib/rsa/rsa-verify.c | 5 ++++- 9 files changed, 26 insertions(+), 4 deletions(-)
diff --git a/Kconfig b/Kconfig index f53759a..4ffcc76 100644 --- a/Kconfig +++ b/Kconfig @@ -183,6 +183,10 @@ config FIT verified boot (secure boot using RSA). This option enables that feature.
+config SPL_FIT + bool "Support Flattened Image Tree in SPL" + depends on FIT + config FIT_VERBOSE bool "Display verbose messages on FIT boot" depends on FIT @@ -205,6 +209,10 @@ config FIT_SIGNATURE format support in this case, enable it using CONFIG_IMAGE_FORMAT_LEGACY.
+config SPL_FIT_SIGNATURE + bool "Enable signature verification of FIT uImages in SPL" + depends on FIT_SIGNATURE + config FIT_BEST_MATCH bool "Select the best match for the kernel device tree" depends on FIT diff --git a/common/Makefile b/common/Makefile index b23f312..647a4ed 100644 --- a/common/Makefile +++ b/common/Makefile @@ -10,7 +10,6 @@ ifndef CONFIG_SPL_BUILD obj-y += init/ obj-y += main.o obj-y += exports.o -obj-y += hash.o ifdef CONFIG_SYS_HUSH_PARSER obj-y += cli_hush.o endif @@ -150,6 +149,8 @@ obj-y += fb_nand.o endif endif
+obj-y += hash.o + # We always have this since drivers/ddr/fs/interactive.c needs it obj-$(CONFIG_CMDLINE) += cli_simple.o
diff --git a/common/image-fit.c b/common/image-fit.c index 25f8a11..12c94e1 100644 --- a/common/image-fit.c +++ b/common/image-fit.c @@ -1502,7 +1502,7 @@ void fit_conf_print(const void *fit, int noffset, const char *p)
static int fit_image_select(const void *fit, int rd_noffset, int verify) { - fit_image_print(fit, rd_noffset, " "); +// fit_image_print(fit, rd_noffset, " ");
if (verify) { puts(" Verifying Hash Integrity ... "); diff --git a/common/spl/spl.c b/common/spl/spl.c index 82e7f58..017ca82 100644 --- a/common/spl/spl.c +++ b/common/spl/spl.c @@ -345,6 +345,7 @@ void board_init_r(gd_t *dummy1, ulong dummy2) int i;
debug(">>spl:board_init_r()\n"); + fit_image_load(NULL, 0, NULL, NULL, 0, 0, 0, 0, NULL, NULL);
#if defined(CONFIG_SYS_SPL_MALLOC_START) mem_malloc_init(CONFIG_SYS_SPL_MALLOC_START, diff --git a/configs/firefly-rk3288_defconfig b/configs/firefly-rk3288_defconfig index 0995f9b..596475c 100644 --- a/configs/firefly-rk3288_defconfig +++ b/configs/firefly-rk3288_defconfig @@ -69,3 +69,8 @@ CONFIG_USE_PRIVATE_LIBGCC=y CONFIG_USE_TINY_PRINTF=y CONFIG_CMD_DHRYSTONE=y CONFIG_ERRNO_STR=y +CONFIG_SPL_FIT=y +CONFIG_SPL_OF_LIBFDT +CONFIG_FIT_SIGNATURE=y +CONFIG_SPL_FIT_SIGNATURE=y +CONFIG_FIT=y diff --git a/drivers/Makefile b/drivers/Makefile index 6900097..baf9dee 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -36,6 +36,7 @@ obj-$(CONFIG_SPL_WATCHDOG_SUPPORT) += watchdog/ obj-$(CONFIG_SPL_USB_HOST_SUPPORT) += usb/host/ obj-$(CONFIG_OMAP_USB_PHY) += usb/phy/ obj-$(CONFIG_SPL_SATA_SUPPORT) += block/ +obj-$(CONFIG_SPL_CRYPTO_SUPPORT) += crypto/
else
diff --git a/include/configs/rk3288_common.h b/include/configs/rk3288_common.h index 8a81397..39bffcb 100644 --- a/include/configs/rk3288_common.h +++ b/include/configs/rk3288_common.h @@ -11,6 +11,8 @@
#include <asm/arch/hardware.h>
+#define CONFIG_SPL_CRYPTO_SUPPORT + #define CONFIG_SYS_NO_FLASH #define CONFIG_NR_DRAM_BANKS 1 #define CONFIG_ENV_SIZE 0x2000 diff --git a/lib/Makefile b/lib/Makefile index 02dfa29..b3ea4bd 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -9,7 +9,6 @@ ifndef CONFIG_SPL_BUILD
obj-$(CONFIG_EFI) += efi/ obj-$(CONFIG_EFI_LOADER) += efi_loader/ -obj-$(CONFIG_RSA) += rsa/ obj-$(CONFIG_LZMA) += lzma/ obj-$(CONFIG_LZO) += lzo/ obj-$(CONFIG_ZLIB) += zlib/ @@ -49,6 +48,8 @@ obj-$(CONFIG_BITREVERSE) += bitrev.o obj-y += list_sort.o endif
+obj-$(CONFIG_RSA) += rsa/ + obj-$(CONFIG_$(SPL_)OF_LIBFDT) += libfdt/ ifdef CONFIG_SPL_OF_CONTROL obj-$(CONFIG_OF_LIBFDT) += libfdt/ diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c index 60126d2..341ce2e 100644 --- a/lib/rsa/rsa-verify.c +++ b/lib/rsa/rsa-verify.c @@ -200,7 +200,10 @@ int rsa_verify(struct image_sign_info *info, }
/* Look for a key that matches our hint */ - snprintf(name, sizeof(name), "key-%s", info->keyname); + // FIXME + //snprintf(name, sizeof(name), "key-%s", info->keyname); + strcpy(name, "key-"); + strcat(name, info->keyname); node = fdt_subnode_offset(blob, sig_node, name); ret = rsa_verify_with_keynode(info, hash, sig, sig_len, node); if (!ret)