mirror of
https://github.com/brain-hackers/u-boot-brain
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4f65ee3813
After we authenticate/decrypt an image we need to flush the caches as they may still contain bits of the encrypted image. This will cause failures if we attempt to jump to this image. Reported-by: Yogesh Siraswar<yogeshs@ti.com> Signed-off-by: Andrew F. Davis <afd@ti.com> Reviewed-by: Tom Rini <trini@konsulko.com>
150 lines
3.6 KiB
C
150 lines
3.6 KiB
C
/*
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*
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* Common security related functions for OMAP devices
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*
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* (C) Copyright 2016
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* Texas Instruments, <www.ti.com>
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*
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* Daniel Allred <d-allred@ti.com>
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* Andreas Dannenberg <dannenberg@ti.com>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <stdarg.h>
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#include <asm/arch/sys_proto.h>
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#include <asm/omap_common.h>
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#include <asm/omap_sec_common.h>
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#include <asm/spl.h>
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#include <spl.h>
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/* Index for signature verify ROM API */
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#ifdef CONFIG_AM33XX
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#define API_HAL_KM_VERIFYCERTIFICATESIGNATURE_INDEX (0x0000000C)
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#else
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#define API_HAL_KM_VERIFYCERTIFICATESIGNATURE_INDEX (0x0000000E)
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#endif
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static uint32_t secure_rom_call_args[5] __aligned(ARCH_DMA_MINALIGN);
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u32 secure_rom_call(u32 service, u32 proc_id, u32 flag, ...)
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{
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int i;
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u32 num_args;
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va_list ap;
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va_start(ap, flag);
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num_args = va_arg(ap, u32);
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if (num_args > 4)
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return 1;
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/* Copy args to aligned args structure */
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for (i = 0; i < num_args; i++)
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secure_rom_call_args[i + 1] = va_arg(ap, u32);
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secure_rom_call_args[0] = num_args;
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va_end(ap);
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/* if data cache is enabled, flush the aligned args structure */
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flush_dcache_range(
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(unsigned int)&secure_rom_call_args[0],
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(unsigned int)&secure_rom_call_args[0] +
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roundup(sizeof(secure_rom_call_args), ARCH_DMA_MINALIGN));
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return omap_smc_sec(service, proc_id, flag, secure_rom_call_args);
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}
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static u32 find_sig_start(char *image, size_t size)
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{
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char *image_end = image + size;
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char *sig_start_magic = "CERT_";
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int magic_str_len = strlen(sig_start_magic);
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char *ch;
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while (--image_end > image) {
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if (*image_end == '_') {
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ch = image_end - magic_str_len + 1;
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if (!strncmp(ch, sig_start_magic, magic_str_len))
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return (u32)ch;
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}
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}
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return 0;
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}
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int secure_boot_verify_image(void **image, size_t *size)
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{
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int result = 1;
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u32 cert_addr, sig_addr;
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size_t cert_size;
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/* Perform cache writeback on input buffer */
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flush_dcache_range(
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(u32)*image,
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(u32)*image + roundup(*size, ARCH_DMA_MINALIGN));
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cert_addr = (uint32_t)*image;
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sig_addr = find_sig_start((char *)*image, *size);
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if (sig_addr == 0) {
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printf("No signature found in image!\n");
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result = 1;
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goto auth_exit;
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}
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*size = sig_addr - cert_addr; /* Subtract out the signature size */
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cert_size = *size;
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/* Check if image load address is 32-bit aligned */
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if (!IS_ALIGNED(cert_addr, 4)) {
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printf("Image is not 4-byte aligned!\n");
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result = 1;
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goto auth_exit;
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}
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/* Image size also should be multiple of 4 */
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if (!IS_ALIGNED(cert_size, 4)) {
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printf("Image size is not 4-byte aligned!\n");
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result = 1;
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goto auth_exit;
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}
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/* Call ROM HAL API to verify certificate signature */
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debug("%s: load_addr = %x, size = %x, sig_addr = %x\n", __func__,
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cert_addr, cert_size, sig_addr);
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result = secure_rom_call(
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API_HAL_KM_VERIFYCERTIFICATESIGNATURE_INDEX, 0, 0,
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4, cert_addr, cert_size, sig_addr, 0xFFFFFFFF);
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/* Perform cache writeback on output buffer */
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flush_dcache_range(
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(u32)*image,
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(u32)*image + roundup(*size, ARCH_DMA_MINALIGN));
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auth_exit:
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if (result != 0) {
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printf("Authentication failed!\n");
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printf("Return Value = %08X\n", result);
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hang();
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}
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/*
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* Output notification of successful authentication as well the name of
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* the signing certificate used to re-assure the user that the secure
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* code is being processed as expected. However suppress any such log
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* output in case of building for SPL and booting via YMODEM. This is
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* done to avoid disturbing the YMODEM serial protocol transactions.
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*/
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if (!(IS_ENABLED(CONFIG_SPL_BUILD) &&
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IS_ENABLED(CONFIG_SPL_YMODEM_SUPPORT) &&
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spl_boot_device() == BOOT_DEVICE_UART))
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printf("Authentication passed: %s\n", (char *)sig_addr);
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return result;
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}
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