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