From: Gabriel Valcazar Date: Wed, 7 Apr 2021 09:15:07 +0200 Subject: [PATCH] Implement support for environment encryption by CAAM Use the md5sum of HWID words (on the device tree) as key modifier. This is based on the u-boot-fw-utils implementation of the CAAM encryption support. Port a subset of U-Boot's md5 implementation. https://jira.digi.com/browse/DEL-7410 https://jira.digi.com/browse/DEL-7185 https://jira.digi.com/browse/DEL-2836 Signed-off-by: Diaz de Grenu, Jose Signed-off-by: Gonzalo Ruiz Signed-off-by: Hector Palacios Signed-off-by: Gabriel Valcazar --- src/CMakeLists.txt | 2 + src/caam_keyblob.h | 42 +++++++ src/md5.c | 275 ++++++++++++++++++++++++++++++++++++++++++++ src/md5.h | 24 ++++ src/uboot_env.c | 131 +++++++++++++++++++++ src/uboot_private.h | 4 + 6 files changed, 478 insertions(+) create mode 100644 src/caam_keyblob.h create mode 100644 src/md5.c create mode 100644 src/md5.h diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt index 4b71bc588827..d7e38a12feed 100644 --- a/src/CMakeLists.txt +++ b/src/CMakeLists.txt @@ -1,6 +1,8 @@ cmake_minimum_required (VERSION 2.6) # Sources and private headers SET(libubootenv_SOURCES + md5.c + md5.h uboot_env.c uboot_private.h ) diff --git a/src/caam_keyblob.h b/src/caam_keyblob.h new file mode 100644 index 000000000000..e313e87a3854 --- /dev/null +++ b/src/caam_keyblob.h @@ -0,0 +1,42 @@ +/* + * CAAM public-level include definitions for the key blob + * + * Copyright (C) 2015 Freescale Semiconductor, Inc. + */ + +#ifndef CAAM_KEYBLOB_H +#define CAAM_KEYBLOB_H + +#include +#include + +struct caam_kb_data { + char *rawkey; + size_t rawkey_len; + char *keyblob; + size_t keyblob_len; + char *keymod; + size_t keymod_len; +}; + +#define CAAM_KB_MAGIC 'I' + +/** + * DOC: CAAM_KB_ENCRYPT - generate a key blob from raw key + * + * Takes an caam_kb_data struct and returns it with the key blob + */ +#define CAAM_KB_ENCRYPT _IOWR(CAAM_KB_MAGIC, 0, struct caam_kb_data) + +/** + * DOC: CAAM_KB_DECRYPT - get keys from a key blob + * + * Takes an caam_kb_data struct and returns it with the raw key. + */ +#define CAAM_KB_DECRYPT _IOWR(CAAM_KB_MAGIC, 1, struct caam_kb_data) + +#ifndef GENMEM_KEYMOD_LEN +#define GENMEM_KEYMOD_LEN 16 +#endif + +#endif /* CAAM_KEYBLOB_H */ diff --git a/src/md5.c b/src/md5.c new file mode 100644 index 000000000000..47ae8bf34a4d --- /dev/null +++ b/src/md5.c @@ -0,0 +1,275 @@ +/* + * This file was transplanted with slight modifications from Linux sources + * (fs/cifs/md5.c) into U-Boot by Bartlomiej Sieka . + */ + +/* + * This code implements the MD5 message-digest algorithm. + * The algorithm is due to Ron Rivest. This code was + * written by Colin Plumb in 1993, no copyright is claimed. + * This code is in the public domain; do with it what you wish. + * + * Equivalent code is available from RSA Data Security, Inc. + * This code has been tested against that, and is equivalent, + * except that you don't need to include two pages of legalese + * with every copy. + * + * To compute the message digest of a chunk of bytes, declare an + * MD5Context structure, pass it to MD5Init, call MD5Update as + * needed on buffers full of bytes, and then call MD5Final, which + * will fill a supplied 16-byte array with the digest. + */ + +/* This code slightly modified to fit into Samba by + abartlet@samba.org Jun 2001 + and to fit the cifs vfs by + Steve French sfrench@us.ibm.com */ + +#include +#include + +#include "md5.h" + +static void +MD5Transform(uint32_t buf[4], uint32_t const in[16]); + +/* + * Note: this code is harmless on little-endian machines. + */ +static void +byteReverse(unsigned char *buf, unsigned longs) +{ + uint32_t t; + do { + t = (uint32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 | + ((unsigned) buf[1] << 8 | buf[0]); + *(uint32_t *) buf = t; + buf += 4; + } while (--longs); +} + +/* + * Start MD5 accumulation. Set bit count to 0 and buffer to mysterious + * initialization constants. + */ +static void +MD5Init(struct MD5Context *ctx) +{ + ctx->buf[0] = 0x67452301; + ctx->buf[1] = 0xefcdab89; + ctx->buf[2] = 0x98badcfe; + ctx->buf[3] = 0x10325476; + + ctx->bits[0] = 0; + ctx->bits[1] = 0; +} + +/* + * Update context to reflect the concatenation of another buffer full + * of bytes. + */ +static void +MD5Update(struct MD5Context *ctx, unsigned char const *buf, unsigned len) +{ + register uint32_t t; + + /* Update bitcount */ + + t = ctx->bits[0]; + if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t) + ctx->bits[1]++; /* Carry from low to high */ + ctx->bits[1] += len >> 29; + + t = (t >> 3) & 0x3f; /* Bytes already in shsInfo->data */ + + /* Handle any leading odd-sized chunks */ + + if (t) { + unsigned char *p = (unsigned char *) ctx->in + t; + + t = 64 - t; + if (len < t) { + memmove(p, buf, len); + return; + } + memmove(p, buf, t); + byteReverse(ctx->in, 16); + MD5Transform(ctx->buf, (uint32_t *) ctx->in); + buf += t; + len -= t; + } + /* Process data in 64-byte chunks */ + + while (len >= 64) { + memmove(ctx->in, buf, 64); + byteReverse(ctx->in, 16); + MD5Transform(ctx->buf, (uint32_t *) ctx->in); + buf += 64; + len -= 64; + } + + /* Handle any remaining bytes of data. */ + + memmove(ctx->in, buf, len); +} + +/* + * Final wrapup - pad to 64-byte boundary with the bit pattern + * 1 0* (64-bit count of bits processed, MSB-first) + */ +static void +MD5Final(unsigned char digest[16], struct MD5Context *ctx) +{ + unsigned int count; + unsigned char *p; + + /* Compute number of bytes mod 64 */ + count = (ctx->bits[0] >> 3) & 0x3F; + + /* Set the first char of padding to 0x80. This is safe since there is + always at least one byte free */ + p = ctx->in + count; + *p++ = 0x80; + + /* Bytes of padding needed to make 64 bytes */ + count = 64 - 1 - count; + + /* Pad out to 56 mod 64 */ + if (count < 8) { + /* Two lots of padding: Pad the first block to 64 bytes */ + memset(p, 0, count); + byteReverse(ctx->in, 16); + MD5Transform(ctx->buf, (uint32_t *) ctx->in); + + /* Now fill the next block with 56 bytes */ + memset(ctx->in, 0, 56); + } else { + /* Pad block to 56 bytes */ + memset(p, 0, count - 8); + } + byteReverse(ctx->in, 14); + + /* Append length in bits and transform */ + ctx->in32[14] = ctx->bits[0]; + ctx->in32[15] = ctx->bits[1]; + + MD5Transform(ctx->buf, (uint32_t *) ctx->in); + byteReverse((unsigned char *) ctx->buf, 4); + memmove(digest, ctx->buf, 16); + memset(ctx, 0, sizeof(*ctx)); /* In case it's sensitive */ +} + +/* The four core functions - F1 is optimized somewhat */ + +/* #define F1(x, y, z) (x & y | ~x & z) */ +#define F1(x, y, z) (z ^ (x & (y ^ z))) +#define F2(x, y, z) F1(z, x, y) +#define F3(x, y, z) (x ^ y ^ z) +#define F4(x, y, z) (y ^ (x | ~z)) + +/* This is the central step in the MD5 algorithm. */ +#define MD5STEP(f, w, x, y, z, data, s) \ + ( w += f(x, y, z) + data, w = w<>(32-s), w += x ) + +/* + * The core of the MD5 algorithm, this alters an existing MD5 hash to + * reflect the addition of 16 longwords of new data. MD5Update blocks + * the data and converts bytes into longwords for this routine. + */ +static void +MD5Transform(uint32_t buf[4], uint32_t const in[16]) +{ + register uint32_t a, b, c, d; + + a = buf[0]; + b = buf[1]; + c = buf[2]; + d = buf[3]; + + MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7); + MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12); + MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17); + MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22); + MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7); + MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12); + MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17); + MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22); + MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7); + MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12); + MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17); + MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22); + MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7); + MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12); + MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17); + MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22); + + MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5); + MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9); + MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14); + MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20); + MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5); + MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9); + MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14); + MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20); + MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5); + MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9); + MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14); + MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20); + MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5); + MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9); + MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14); + MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20); + + MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4); + MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11); + MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16); + MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23); + MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4); + MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11); + MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16); + MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23); + MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4); + MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11); + MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16); + MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23); + MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4); + MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11); + MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16); + MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23); + + MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6); + MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10); + MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15); + MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21); + MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6); + MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10); + MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15); + MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21); + MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6); + MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10); + MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15); + MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21); + MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6); + MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10); + MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15); + MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21); + + buf[0] += a; + buf[1] += b; + buf[2] += c; + buf[3] += d; +} + +/* + * Calculate and store in 'output' the MD5 digest of 'len' bytes at + * 'input'. 'output' must have enough space to hold 16 bytes. + */ +void +md5 (unsigned char *input, int len, unsigned char output[16]) +{ + struct MD5Context context; + + MD5Init(&context); + MD5Update(&context, input, len); + MD5Final(output, &context); +} diff --git a/src/md5.h b/src/md5.h new file mode 100644 index 000000000000..02a9a9d23e34 --- /dev/null +++ b/src/md5.h @@ -0,0 +1,24 @@ +/* + * This file was transplanted with slight modifications from Linux sources + * (fs/cifs/md5.h) into U-Boot by Bartlomiej Sieka . + */ + +#ifndef _MD5_H +#define _MD5_H + +struct MD5Context { + uint32_t buf[4]; + uint32_t bits[2]; + union { + unsigned char in[64]; + uint32_t in32[16]; + }; +}; + +/* + * Calculate and store in 'output' the MD5 digest of 'len' bytes at + * 'input'. 'output' must have enough space to hold 16 bytes. + */ +void md5 (unsigned char *input, int len, unsigned char output[16]); + +#endif /* _MD5_H */ diff --git a/src/uboot_env.c b/src/uboot_env.c index 30c39ebf6fa9..2fd08f5a07db 100644 --- a/src/uboot_env.c +++ b/src/uboot_env.c @@ -33,11 +33,21 @@ #include #include #include +#include #include #include +#include "caam_keyblob.h" +#include "md5.h" #include "uboot_private.h" +/* + * The BLOB includes a random AES-256 key (32 bytes) and a + * Message Authentication Code (MAC) (16 bytes) + */ +#define BLOB_OVERHEAD 48 +#define CAAM_KEY_DEV "/dev/caam_kb" + #define UBI_MAX_VOLUME 128 #define DEVICE_MTD_NAME "/dev/mtd" @@ -844,6 +854,105 @@ static int set_obsolete_flag(struct uboot_flash_env *dev) return ret; } +static int is_env_encrypted(void) +{ + const char *dt_prop = "/proc/device-tree/digi,uboot-env,encrypted"; + + return access(dt_prop, F_OK) != -1; +} + +#define MAX_HWID_WORDS 4 +static int env_caam_get_keymod(unsigned char output[16]) +{ + int i; + int len; + int fd; + uint32_t ocotp_hwid[MAX_HWID_WORDS]; + char dt_prop[32]; + + for (i = 0; i < MAX_HWID_WORDS; i++) { + sprintf(dt_prop, "/proc/device-tree/digi,hwid_%d", i); + if (access(dt_prop, F_OK) != -1) { + char buf[sizeof(uint32_t)]; + + fd = open(dt_prop, O_RDONLY); + if (fd < 0) + return fd; + len = read(fd, buf, sizeof(uint32_t)); + if (len < 0) { + close(fd); + return -1; + } + ocotp_hwid[i] = ntohl(*(uint32_t *)buf); + close(fd); + } else { + break; + } + } + + /* Calculate md5sum on the raw HWID array */ + md5((unsigned char *)(&ocotp_hwid), sizeof(uint32_t) * i, output); + + return 0; +} + +static int env_caam_crypt(char *data, unsigned int size, const int enc) +{ + struct caam_kb_data enc_data; + int fd; + int ret = 0; + const int len = size; + int ioctl_mode; + char *buffer; + unsigned char key_modifier[16]; + + ret = env_caam_get_keymod(key_modifier); + if (ret) + return ret; + + enc_data.keymod = (char *)key_modifier; + enc_data.keymod_len = sizeof(key_modifier); + + enc_data.keyblob_len = len; + enc_data.rawkey_len = len - BLOB_OVERHEAD; + + buffer = malloc(len); + if (!buffer) { + printf("Could not allocate memory\n"); + return -1; + } + + if (enc) { + enc_data.rawkey = data; + ioctl_mode = CAAM_KB_ENCRYPT; + enc_data.keyblob = buffer; + } else { + enc_data.keyblob = data; + ioctl_mode = CAAM_KB_DECRYPT; + enc_data.rawkey = buffer; + } + + if ((fd = open(CAAM_KEY_DEV, O_RDWR)) < 0) { + ret = fd; + goto free; + } + + ret = ioctl(fd, ioctl_mode, &enc_data); + if (ret) { + printf("CAAM_KEY_DEV ioctl failed: %d\n", ret); + goto out; + } + + memcpy(data, buffer, enc ? len : len - BLOB_OVERHEAD); + +out: + close(fd); +free: + free(buffer); + + return ret; +} + int libuboot_env_store(struct uboot_ctx *ctx) { struct var_entry *entry; @@ -919,6 +1028,15 @@ int libuboot_env_store(struct uboot_ctx *ctx) ((struct uboot_env_redund *)image)->flags = flags; } + if (ctx->encrypted) { + ret = env_caam_crypt(data, ctx->usable_size, 1); + if (ret) { + fprintf(stderr, + "Error: can't encrypt env for flash\n"); + return ret; + } + } + *(uint32_t *)image = crc32(0, (uint8_t *)data, ctx->size - offsetdata); copy = ctx->redundant ? (ctx->current ? 0 : 1) : 0; @@ -984,6 +1102,13 @@ static int libuboot_load(struct uboot_ctx *ctx) } crc = *(uint32_t *)(buf[i] + offsetcrc); dev->crc = crc32(0, (uint8_t *)data, usable_envsize); + if (ctx->encrypted) { + ret = env_caam_crypt((char *)data, ctx->usable_size, 0); + if (ret) { + fprintf(stderr, "Error: can't decrypt environment\n"); + return ret; + } + } crcenv[i] = dev->crc == crc; if (ctx->redundant) dev->flags = *(uint8_t *)(buf[i] + offsetflags); @@ -1264,6 +1389,11 @@ int libuboot_read_config(struct uboot_ctx *ctx, const char *config) break; } } + + ctx->usable_size = ctx->size - sizeof(uint32_t); + if (ctx->redundant) + ctx->usable_size -= sizeof(char); + if (ndev == 0) retval = -EINVAL; @@ -1461,6 +1591,7 @@ int libuboot_initialize(struct uboot_ctx **out, return -ENOMEM; ctx->valid = false; + ctx->encrypted = is_env_encrypted(); ret = libuboot_configure(ctx, envdevs); if (ret < 0) { diff --git a/src/uboot_private.h b/src/uboot_private.h index 4b7a9f9602a6..22c8c14ce8cc 100644 --- a/src/uboot_private.h +++ b/src/uboot_private.h @@ -111,10 +111,14 @@ LIST_HEAD(vars, var_entry); struct uboot_ctx { /** true if the environment is redundant */ bool redundant; + /** true if the environment is encrypted */ + bool encrypted; /** set to valid after a successful load */ bool valid; /** size of the environment */ size_t size; + /** usable environment size */ + unsigned int usable_size; /** devices where environment is stored */ struct uboot_flash_env envdevs[2]; /** Set which device contains the current(last valid) environment */