1 /* 2 * 3 * Common security related functions for OMAP devices 4 * 5 * (C) Copyright 2016 6 * Texas Instruments, <www.ti.com> 7 * 8 * Daniel Allred <d-allred@ti.com> 9 * Andreas Dannenberg <dannenberg@ti.com> 10 * 11 * SPDX-License-Identifier: GPL-2.0+ 12 */ 13 14 #include <common.h> 15 #include <stdarg.h> 16 17 #include <asm/arch/sys_proto.h> 18 #include <asm/omap_common.h> 19 #include <asm/omap_sec_common.h> 20 #include <asm/spl.h> 21 #include <spl.h> 22 23 /* Index for signature verify ROM API */ 24 #ifdef CONFIG_AM33XX 25 #define API_HAL_KM_VERIFYCERTIFICATESIGNATURE_INDEX (0x0000000C) 26 #else 27 #define API_HAL_KM_VERIFYCERTIFICATESIGNATURE_INDEX (0x0000000E) 28 #endif 29 30 static uint32_t secure_rom_call_args[5] __aligned(ARCH_DMA_MINALIGN); 31 32 u32 secure_rom_call(u32 service, u32 proc_id, u32 flag, ...) 33 { 34 int i; 35 u32 num_args; 36 va_list ap; 37 38 va_start(ap, flag); 39 40 num_args = va_arg(ap, u32); 41 42 if (num_args > 4) 43 return 1; 44 45 /* Copy args to aligned args structure */ 46 for (i = 0; i < num_args; i++) 47 secure_rom_call_args[i + 1] = va_arg(ap, u32); 48 49 secure_rom_call_args[0] = num_args; 50 51 va_end(ap); 52 53 /* if data cache is enabled, flush the aligned args structure */ 54 flush_dcache_range( 55 (unsigned int)&secure_rom_call_args[0], 56 (unsigned int)&secure_rom_call_args[0] + 57 roundup(sizeof(secure_rom_call_args), ARCH_DMA_MINALIGN)); 58 59 return omap_smc_sec(service, proc_id, flag, secure_rom_call_args); 60 } 61 62 static u32 find_sig_start(char *image, size_t size) 63 { 64 char *image_end = image + size; 65 char *sig_start_magic = "CERT_"; 66 int magic_str_len = strlen(sig_start_magic); 67 char *ch; 68 69 while (--image_end > image) { 70 if (*image_end == '_') { 71 ch = image_end - magic_str_len + 1; 72 if (!strncmp(ch, sig_start_magic, magic_str_len)) 73 return (u32)ch; 74 } 75 } 76 return 0; 77 } 78 79 int secure_boot_verify_image(void **image, size_t *size) 80 { 81 int result = 1; 82 u32 cert_addr, sig_addr; 83 size_t cert_size; 84 85 /* Perform cache writeback on input buffer */ 86 flush_dcache_range( 87 (u32)*image, 88 (u32)*image + roundup(*size, ARCH_DMA_MINALIGN)); 89 90 cert_addr = (uint32_t)*image; 91 sig_addr = find_sig_start((char *)*image, *size); 92 93 if (sig_addr == 0) { 94 printf("No signature found in image!\n"); 95 result = 1; 96 goto auth_exit; 97 } 98 99 *size = sig_addr - cert_addr; /* Subtract out the signature size */ 100 cert_size = *size; 101 102 /* Check if image load address is 32-bit aligned */ 103 if (!IS_ALIGNED(cert_addr, 4)) { 104 printf("Image is not 4-byte aligned!\n"); 105 result = 1; 106 goto auth_exit; 107 } 108 109 /* Image size also should be multiple of 4 */ 110 if (!IS_ALIGNED(cert_size, 4)) { 111 printf("Image size is not 4-byte aligned!\n"); 112 result = 1; 113 goto auth_exit; 114 } 115 116 /* Call ROM HAL API to verify certificate signature */ 117 debug("%s: load_addr = %x, size = %x, sig_addr = %x\n", __func__, 118 cert_addr, cert_size, sig_addr); 119 120 result = secure_rom_call( 121 API_HAL_KM_VERIFYCERTIFICATESIGNATURE_INDEX, 0, 0, 122 4, cert_addr, cert_size, sig_addr, 0xFFFFFFFF); 123 auth_exit: 124 if (result != 0) { 125 printf("Authentication failed!\n"); 126 printf("Return Value = %08X\n", result); 127 hang(); 128 } 129 130 /* 131 * Output notification of successful authentication as well the name of 132 * the signing certificate used to re-assure the user that the secure 133 * code is being processed as expected. However suppress any such log 134 * output in case of building for SPL and booting via YMODEM. This is 135 * done to avoid disturbing the YMODEM serial protocol transactions. 136 */ 137 if (!(IS_ENABLED(CONFIG_SPL_BUILD) && 138 IS_ENABLED(CONFIG_SPL_YMODEM_SUPPORT) && 139 spl_boot_device() == BOOT_DEVICE_UART)) 140 printf("Authentication passed: %s\n", (char *)sig_addr); 141 142 return result; 143 } 144