Public exponentiation which is required in rsa verify functionality is currently tightly integrated with verification code in rsa_verify.c. Currently this implementation is software based. Some platforms having support of the exponentiation in hardware. To enable the rsa verify functionality to use the Modular exponentiation if present in hardware, the patch-set splits the file into two files:

1. rsa-verify.c - The file parses device tree keys node to fill a keyprop structure. The keyprop structure can then be converted to implementation specific formal (struct rsa_pub_key for sw implementation). - The parsed device tree node is then passed to a generic rsa_mod_exp function.

2. rsa-mod-exp.c Move the software specific functions related to exponentiation from rsa-verify.c to this file. The file is compiled if "CONFIG_RSA_MOD_EXP_SW" is defined. In general if both CONFIG_FIT_SIGNATURE and CONFIG_RSA are defined, CONFIG_RSA_MOD_EXP_SW gets automatically defined.

Platforms having hardware implementation for rsa_mod_exp can add a define "CONFIG_RSA_MOD_EXP_HW" to their config files. Adding this defined, undefs the CONFIG_RSA_MOD_EXP_SW and hardware implementation of mod_exp gets compiled.

Signed-off-by: Ruchika Gupta ruchika.gupta@freescale.com CC: Simon Glass sjg@chromium.org --- Changes in v2: Addressed few of Simon Glass's comments: - Kconfig option added for RSA - Comments added for new keyprop struct

Kconfig | 2 + include/config_fallbacks.h | 8 ++ include/u-boot/rsa-mod-exp.h | 34 +++++ lib/Kconfig | 15 +++ lib/rsa/Makefile | 1 + lib/rsa/rsa-mod-exp.c | 308 +++++++++++++++++++++++++++++++++++++++++++ lib/rsa/rsa-verify.c | 307 +++++------------------------------------- tools/Makefile | 2 +- 8 files changed, 399 insertions(+), 278 deletions(-) create mode 100644 include/u-boot/rsa-mod-exp.h create mode 100644 lib/rsa/rsa-mod-exp.c

diff --git a/Kconfig b/Kconfig index 153ee2b..82b14bd 100644 --- a/Kconfig +++ b/Kconfig @@ -101,6 +101,7 @@ config TPL help If you want to build TPL as well as the normal image and SPL, say Y.

+ config FIT bool "Support Flattened Image Tree" depends on !SPL_BUILD @@ -118,6 +119,7 @@ config FIT_VERBOSE config FIT_SIGNATURE bool "Enabel signature verification of FIT uImages" depends on FIT + select RSA help This option enables signature verification of FIT uImages, using a hash signed and verified using RSA. diff --git a/include/config_fallbacks.h b/include/config_fallbacks.h index ddfe045..b46bef9 100644 --- a/include/config_fallbacks.h +++ b/include/config_fallbacks.h @@ -83,6 +83,14 @@ #define CONFIG_SYS_PBSIZE (CONFIG_SYS_CBSIZE + 128) #endif

+/* This can be removed once all platforms move to defconfig + * option to enable FIT_SIGNATURE + */ +#if defined(CONFIG_FIT_SIGNATURE) && defined(CONFIG_RSA) && \ + !defined(CONFIG_RSA_MOD_EXP_HW) && !defined(CONFIG_RSA_MOD_EXP_SW) +#define CONFIG_RSA_MOD_EXP_SW +#endif + #ifndef CONFIG_FIT_SIGNATURE #define CONFIG_IMAGE_FORMAT_LEGACY #endif diff --git a/include/u-boot/rsa-mod-exp.h b/include/u-boot/rsa-mod-exp.h new file mode 100644 index 0000000..0d2ccd6 --- /dev/null +++ b/include/u-boot/rsa-mod-exp.h @@ -0,0 +1,34 @@ +/* + * Copyright (c) 2014, Ruchika Gupta. + * + * SPDX-License-Identifier: GPL-2.0+ +*/ + +#ifndef _RSA_MOD_EXP_H +#define _RSA_MOD_EXP_H + +#include <errno.h> +#include <image.h> + +/** + * struct key_prop - holder for a public key properties + * + * The struct has pointers to modulus (Typically called N), + * The inverse, R^2, exponent. These can be typecasted and + * used as byte arrays or converted to the required format + * as per requirement of RSA implementation. + * + */ +struct key_prop { + const void *rr; /* R^2 can be treated as byte array */ + const void *modulus; /* modulus as byte array */ + const void *public_exponent; /* public exponent as byte array */ + uint32_t n0inv; /* -1 / modulus[0] mod 2^32 */ + int num_bits; /* Key length in bits */ + uint32_t exp_len; /* Exponent length in number of uint8_t */ +}; + +int rsa_mod_exp(const uint8_t *sig, uint32_t sig_len, + struct key_prop *node, uint8_t *out); + +#endif diff --git a/lib/Kconfig b/lib/Kconfig index 8460439..a921bb3 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -27,4 +27,19 @@ config SYS_HZ get_timer() must operate in milliseconds and this option must be set to 1000.

+config RSA + bool "Use RSA Library" + help + RSA support + +if RSA + +config RSA_MOD_EXP_SW + depends on RSA + bool "Implement RSA Modular Exponentiation in software" + default y + help + Modular Exponentiation support in SW + +endif endmenu diff --git a/lib/rsa/Makefile b/lib/rsa/Makefile index a5a96cb6..ccc6060 100644 --- a/lib/rsa/Makefile +++ b/lib/rsa/Makefile @@ -8,3 +8,4 @@ #

obj-$(CONFIG_FIT_SIGNATURE) += rsa-verify.o rsa-checksum.o +obj-$(CONFIG_RSA_MOD_EXP_SW) += rsa-mod-exp.o diff --git a/lib/rsa/rsa-mod-exp.c b/lib/rsa/rsa-mod-exp.c new file mode 100644 index 0000000..f69ae1b --- /dev/null +++ b/lib/rsa/rsa-mod-exp.c @@ -0,0 +1,308 @@ +/* + * Copyright (c) 2013, Google Inc. + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#ifndef USE_HOSTCC +#include <common.h> +#include <fdtdec.h> +#include <asm/types.h> +#include <asm/byteorder.h> +#include <asm/errno.h> +#include <asm/types.h> +#include <asm/unaligned.h> +#else +#include "fdt_host.h" +#include "mkimage.h" +#include <fdt_support.h> +#endif +#include <u-boot/rsa.h> +#include <u-boot/rsa-mod-exp.h> + +#define UINT64_MULT32(v, multby) (((uint64_t)(v)) * ((uint32_t)(multby))) + +#define get_unaligned_be32(a) fdt32_to_cpu(*(uint32_t *)a) +#define put_unaligned_be32(a, b) (*(uint32_t *)(b) = cpu_to_fdt32(a)) + +/* Default public exponent for backward compatibility */ +#define RSA_DEFAULT_PUBEXP 65537 + +/** + * subtract_modulus() - subtract modulus from the given value + * + * @key: Key containing modulus to subtract + * @num: Number to subtract modulus from, as little endian word array + */ +static void subtract_modulus(const struct rsa_public_key *key, uint32_t num[]) +{ + int64_t acc = 0; + uint i; + + for (i = 0; i < key->len; i++) { + acc += (uint64_t)num[i] - key->modulus[i]; + num[i] = (uint32_t)acc; + acc >>= 32; + } +} + +/** + * greater_equal_modulus() - check if a value is >= modulus + * + * @key: Key containing modulus to check + * @num: Number to check against modulus, as little endian word array + * @return 0 if num < modulus, 1 if num >= modulus + */ +static int greater_equal_modulus(const struct rsa_public_key *key, + uint32_t num[]) +{ + int i; + + for (i = (int)key->len - 1; i >= 0; i--) { + if (num[i] < key->modulus[i]) + return 0; + if (num[i] > key->modulus[i]) + return 1; + } + + return 1; /* equal */ +} + +/** + * montgomery_mul_add_step() - Perform montgomery multiply-add step + * + * Operation: montgomery result[] += a * b[] / n0inv % modulus + * + * @key: RSA key + * @result: Place to put result, as little endian word array + * @a: Multiplier + * @b: Multiplicand, as little endian word array + */ +static void montgomery_mul_add_step(const struct rsa_public_key *key, + uint32_t result[], const uint32_t a, const uint32_t b[]) +{ + uint64_t acc_a, acc_b; + uint32_t d0; + uint i; + + acc_a = (uint64_t)a * b[0] + result[0]; + d0 = (uint32_t)acc_a * key->n0inv; + acc_b = (uint64_t)d0 * key->modulus[0] + (uint32_t)acc_a; + for (i = 1; i < key->len; i++) { + acc_a = (acc_a >> 32) + (uint64_t)a * b[i] + result[i]; + acc_b = (acc_b >> 32) + (uint64_t)d0 * key->modulus[i] + + (uint32_t)acc_a; + result[i - 1] = (uint32_t)acc_b; + } + + acc_a = (acc_a >> 32) + (acc_b >> 32); + + result[i - 1] = (uint32_t)acc_a; + + if (acc_a >> 32) + subtract_modulus(key, result); +} + +/** + * montgomery_mul() - Perform montgomery mutitply + * + * Operation: montgomery result[] = a[] * b[] / n0inv % modulus + * + * @key: RSA key + * @result: Place to put result, as little endian word array + * @a: Multiplier, as little endian word array + * @b: Multiplicand, as little endian word array + */ +static void montgomery_mul(const struct rsa_public_key *key, + uint32_t result[], uint32_t a[], const uint32_t b[]) +{ + uint i; + + for (i = 0; i < key->len; ++i) + result[i] = 0; + for (i = 0; i < key->len; ++i) + montgomery_mul_add_step(key, result, a[i], b); +} + +/** + * num_pub_exponent_bits() - Number of bits in the public exponent + * + * @key: RSA key + * @num_bits: Storage for the number of public exponent bits + */ +static int num_public_exponent_bits(const struct rsa_public_key *key, + int *num_bits) +{ + uint64_t exponent; + int exponent_bits; + const uint max_bits = (sizeof(exponent) * 8); + + exponent = key->exponent; + exponent_bits = 0; + + if (!exponent) { + *num_bits = exponent_bits; + return 0; + } + + for (exponent_bits = 1; exponent_bits < max_bits + 1; ++exponent_bits) + if (!(exponent >>= 1)) { + *num_bits = exponent_bits; + return 0; + } + + return -EINVAL; +} + +/** + * is_public_exponent_bit_set() - Check if a bit in the public exponent is set + * + * @key: RSA key + * @pos: The bit position to check + */ +static int is_public_exponent_bit_set(const struct rsa_public_key *key, + int pos) +{ + return key->exponent & (1ULL << pos); +} + +/** + * pow_mod() - in-place public exponentiation + * + * @key: RSA key + * @inout: Big-endian word array containing value and result + */ +static int pow_mod(const struct rsa_public_key *key, uint32_t *inout) +{ + uint32_t *result, *ptr; + uint i; + int j, k; + + /* Sanity check for stack size - key->len is in 32-bit words */ + if (key->len > RSA_MAX_KEY_BITS / 32) { + debug("RSA key words %u exceeds maximum %d\n", key->len, + RSA_MAX_KEY_BITS / 32); + return -EINVAL; + } + + uint32_t val[key->len], acc[key->len], tmp[key->len]; + uint32_t a_scaled[key->len]; + result = tmp; /* Re-use location. */ + + /* Convert from big endian byte array to little endian word array. */ + for (i = 0, ptr = inout + key->len - 1; i < key->len; i++, ptr--) + val[i] = get_unaligned_be32(ptr); + + if (0 != num_public_exponent_bits(key, &k)) + return -EINVAL; + + if (k < 2) { + debug("Public exponent is too short (%d bits, minimum 2)\n", + k); + return -EINVAL; + } + + if (!is_public_exponent_bit_set(key, 0)) { + debug("LSB of RSA public exponent must be set.\n"); + return -EINVAL; + } + + /* the bit at e[k-1] is 1 by definition, so start with: C := M */ + montgomery_mul(key, acc, val, key->rr); /* acc = a * RR / R mod n */ + /* retain scaled version for intermediate use */ + memcpy(a_scaled, acc, key->len * sizeof(a_scaled[0])); + + for (j = k - 2; j > 0; --j) { + montgomery_mul(key, tmp, acc, acc); /* tmp = acc^2 / R mod n */ + + if (is_public_exponent_bit_set(key, j)) { + /* acc = tmp * val / R mod n */ + montgomery_mul(key, acc, tmp, a_scaled); + } else { + /* e[j] == 0, copy tmp back to acc for next operation */ + memcpy(acc, tmp, key->len * sizeof(acc[0])); + } + } + + /* the bit at e[0] is always 1 */ + montgomery_mul(key, tmp, acc, acc); /* tmp = acc^2 / R mod n */ + montgomery_mul(key, acc, tmp, val); /* acc = tmp * a / R mod M */ + memcpy(result, acc, key->len * sizeof(result[0])); + + /* Make sure result < mod; result is at most 1x mod too large. */ + if (greater_equal_modulus(key, result)) + subtract_modulus(key, result); + + /* Convert to bigendian byte array */ + for (i = key->len - 1, ptr = inout; (int)i >= 0; i--, ptr++) + put_unaligned_be32(result[i], ptr); + return 0; +} + + +static void rsa_convert_big_endian(uint32_t *dst, const uint32_t *src, int len) +{ + int i; + + for (i = 0; i < len; i++) + dst[i] = fdt32_to_cpu(src[len - 1 - i]); +} + +int rsa_mod_exp(const uint8_t *sig, uint32_t sig_len, + struct key_prop *prop, uint8_t *out) +{ + struct rsa_public_key key; + int ret; + + if (!prop) { + debug("%s: Skipping invalid prop", __func__); + return -EBADF; + } + if (!prop->n0inv) { + debug("%s: Missing rsa,n0-inverse", __func__); + return -EFAULT; + } + key.n0inv = prop->n0inv; + key.len = prop->num_bits; + + if (!prop->public_exponent) + key.exponent = RSA_DEFAULT_PUBEXP; + else + key.exponent = + fdt64_to_cpu(*((uint64_t *)(prop->public_exponent))); + + if (!key.len || !prop->modulus || !prop->rr) { + debug("%s: Missing RSA key info", __func__); + return -EFAULT; + } + + /* Sanity check for stack size */ + if (key.len > RSA_MAX_KEY_BITS || key.len < RSA_MIN_KEY_BITS) { + debug("RSA key bits %u outside allowed range %d..%d\n", + key.len, RSA_MIN_KEY_BITS, RSA_MAX_KEY_BITS); + return -EFAULT; + } + key.len /= sizeof(uint32_t) * 8; + uint32_t key1[key.len], key2[key.len]; + + key.modulus = key1; + key.rr = key2; + rsa_convert_big_endian(key.modulus, (uint32_t *)prop->modulus, key.len); + rsa_convert_big_endian(key.rr, (uint32_t *)prop->rr, key.len); + if (!key.modulus || !key.rr) { + debug("%s: Out of memory", __func__); + return -ENOMEM; + } + + uint32_t buf[sig_len / sizeof(uint32_t)]; + + memcpy(buf, sig, sig_len); + + ret = pow_mod(&key, buf); + if (ret) + return ret; + + memcpy(out, buf, sig_len); + + return 0; +} diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c index 4ef19b6..583400f 100644 --- a/lib/rsa/rsa-verify.c +++ b/lib/rsa/rsa-verify.c @@ -17,230 +17,13 @@ #include "mkimage.h" #include <fdt_support.h> #endif +#include <u-boot/rsa-mod-exp.h> #include <u-boot/rsa.h> -#include <u-boot/sha1.h> -#include <u-boot/sha256.h> - -#define UINT64_MULT32(v, multby) (((uint64_t)(v)) * ((uint32_t)(multby))) - -#define get_unaligned_be32(a) fdt32_to_cpu(*(uint32_t *)a) -#define put_unaligned_be32(a, b) (*(uint32_t *)(b) = cpu_to_fdt32(a))

/* Default public exponent for backward compatibility */ #define RSA_DEFAULT_PUBEXP 65537

-/** - * subtract_modulus() - subtract modulus from the given value - * - * @key: Key containing modulus to subtract - * @num: Number to subtract modulus from, as little endian word array - */ -static void subtract_modulus(const struct rsa_public_key *key, uint32_t num[]) -{ - int64_t acc = 0; - uint i; - - for (i = 0; i < key->len; i++) { - acc += (uint64_t)num[i] - key->modulus[i]; - num[i] = (uint32_t)acc; - acc >>= 32; - } -} - -/** - * greater_equal_modulus() - check if a value is >= modulus - * - * @key: Key containing modulus to check - * @num: Number to check against modulus, as little endian word array - * @return 0 if num < modulus, 1 if num >= modulus - */ -static int greater_equal_modulus(const struct rsa_public_key *key, - uint32_t num[]) -{ - int i; - - for (i = (int)key->len - 1; i >= 0; i--) { - if (num[i] < key->modulus[i]) - return 0; - if (num[i] > key->modulus[i]) - return 1; - } - - return 1; /* equal */ -} - -/** - * montgomery_mul_add_step() - Perform montgomery multiply-add step - * - * Operation: montgomery result[] += a * b[] / n0inv % modulus - * - * @key: RSA key - * @result: Place to put result, as little endian word array - * @a: Multiplier - * @b: Multiplicand, as little endian word array - */ -static void montgomery_mul_add_step(const struct rsa_public_key *key, - uint32_t result[], const uint32_t a, const uint32_t b[]) -{ - uint64_t acc_a, acc_b; - uint32_t d0; - uint i; - - acc_a = (uint64_t)a * b[0] + result[0]; - d0 = (uint32_t)acc_a * key->n0inv; - acc_b = (uint64_t)d0 * key->modulus[0] + (uint32_t)acc_a; - for (i = 1; i < key->len; i++) { - acc_a = (acc_a >> 32) + (uint64_t)a * b[i] + result[i]; - acc_b = (acc_b >> 32) + (uint64_t)d0 * key->modulus[i] + - (uint32_t)acc_a; - result[i - 1] = (uint32_t)acc_b; - } - - acc_a = (acc_a >> 32) + (acc_b >> 32); - - result[i - 1] = (uint32_t)acc_a; - - if (acc_a >> 32) - subtract_modulus(key, result); -} - -/** - * montgomery_mul() - Perform montgomery mutitply - * - * Operation: montgomery result[] = a[] * b[] / n0inv % modulus - * - * @key: RSA key - * @result: Place to put result, as little endian word array - * @a: Multiplier, as little endian word array - * @b: Multiplicand, as little endian word array - */ -static void montgomery_mul(const struct rsa_public_key *key, - uint32_t result[], uint32_t a[], const uint32_t b[]) -{ - uint i; - - for (i = 0; i < key->len; ++i) - result[i] = 0; - for (i = 0; i < key->len; ++i) - montgomery_mul_add_step(key, result, a[i], b); -} - -/** - * num_pub_exponent_bits() - Number of bits in the public exponent - * - * @key: RSA key - * @num_bits: Storage for the number of public exponent bits - */ -static int num_public_exponent_bits(const struct rsa_public_key *key, - int *num_bits) -{ - uint64_t exponent; - int exponent_bits; - const uint max_bits = (sizeof(exponent) * 8); - - exponent = key->exponent; - exponent_bits = 0; - - if (!exponent) { - *num_bits = exponent_bits; - return 0; - } - - for (exponent_bits = 1; exponent_bits < max_bits + 1; ++exponent_bits) - if (!(exponent >>= 1)) { - *num_bits = exponent_bits; - return 0; - } - - return -EINVAL; -} - -/** - * is_public_exponent_bit_set() - Check if a bit in the public exponent is set - * - * @key: RSA key - * @pos: The bit position to check - */ -static int is_public_exponent_bit_set(const struct rsa_public_key *key, - int pos) -{ - return key->exponent & (1ULL << pos); -} - -/** - * pow_mod() - in-place public exponentiation - * - * @key: RSA key - * @inout: Big-endian word array containing value and result - */ -static int pow_mod(const struct rsa_public_key *key, uint32_t *inout) -{ - uint32_t *result, *ptr; - uint i; - int j, k; - - /* Sanity check for stack size - key->len is in 32-bit words */ - if (key->len > RSA_MAX_KEY_BITS / 32) { - debug("RSA key words %u exceeds maximum %d\n", key->len, - RSA_MAX_KEY_BITS / 32); - return -EINVAL; - } - - uint32_t val[key->len], acc[key->len], tmp[key->len]; - uint32_t a_scaled[key->len]; - result = tmp; /* Re-use location. */ - - /* Convert from big endian byte array to little endian word array. */ - for (i = 0, ptr = inout + key->len - 1; i < key->len; i++, ptr--) - val[i] = get_unaligned_be32(ptr); - - if (0 != num_public_exponent_bits(key, &k)) - return -EINVAL; - - if (k < 2) { - debug("Public exponent is too short (%d bits, minimum 2)\n", - k); - return -EINVAL; - } - - if (!is_public_exponent_bit_set(key, 0)) { - debug("LSB of RSA public exponent must be set.\n"); - return -EINVAL; - } - - /* the bit at e[k-1] is 1 by definition, so start with: C := M */ - montgomery_mul(key, acc, val, key->rr); /* acc = a * RR / R mod n */ - /* retain scaled version for intermediate use */ - memcpy(a_scaled, acc, key->len * sizeof(a_scaled[0])); - - for (j = k - 2; j > 0; --j) { - montgomery_mul(key, tmp, acc, acc); /* tmp = acc^2 / R mod n */ - - if (is_public_exponent_bit_set(key, j)) { - /* acc = tmp * val / R mod n */ - montgomery_mul(key, acc, tmp, a_scaled); - } else { - /* e[j] == 0, copy tmp back to acc for next operation */ - memcpy(acc, tmp, key->len * sizeof(acc[0])); - } - } - - /* the bit at e[0] is always 1 */ - montgomery_mul(key, tmp, acc, acc); /* tmp = acc^2 / R mod n */ - montgomery_mul(key, acc, tmp, val); /* acc = tmp * a / R mod M */ - memcpy(result, acc, key->len * sizeof(result[0])); - - /* Make sure result < mod; result is at most 1x mod too large. */ - if (greater_equal_modulus(key, result)) - subtract_modulus(key, result); - - /* Convert to bigendian byte array */ - for (i = key->len - 1, ptr = inout; (int)i >= 0; i--, ptr++) - put_unaligned_be32(result[i], ptr); - return 0; -} - -static int rsa_verify_key(const struct rsa_public_key *key, const uint8_t *sig, +static int rsa_verify_key(struct key_prop *node, const uint8_t *sig, const uint32_t sig_len, const uint8_t *hash, struct checksum_algo *algo) { @@ -248,10 +31,10 @@ static int rsa_verify_key(const struct rsa_public_key *key, const uint8_t *sig, int pad_len; int ret;

- if (!key || !sig || !hash || !algo) + if (!node || !sig || !hash || !algo) return -EIO;

- if (sig_len != (key->len * sizeof(uint32_t))) { + if (sig_len != (node->num_bits / 8)) { debug("Signature is of incorrect length %d\n", sig_len); return -EINVAL; } @@ -265,13 +48,13 @@ static int rsa_verify_key(const struct rsa_public_key *key, const uint8_t *sig, return -EINVAL; }

- uint32_t buf[sig_len / sizeof(uint32_t)]; - - memcpy(buf, sig, sig_len); + uint8_t buf[sig_len];

- ret = pow_mod(key, buf); - if (ret) + ret = rsa_mod_exp(sig, sig_len, node, buf); + if (ret) { + debug("Error in Modular exponentation\n"); return ret; + }

padding = algo->rsa_padding; pad_len = algo->pad_len - algo->checksum_len; @@ -291,72 +74,42 @@ static int rsa_verify_key(const struct rsa_public_key *key, const uint8_t *sig, return 0; }

-static void rsa_convert_big_endian(uint32_t *dst, const uint32_t *src, int len) -{ - int i; - - for (i = 0; i < len; i++) - dst[i] = fdt32_to_cpu(src[len - 1 - i]); -} - static int rsa_verify_with_keynode(struct image_sign_info *info, - const void *hash, uint8_t *sig, uint sig_len, int node) + const void *hash, uint8_t *sig, + uint sig_len, int node) { const void *blob = info->fdt_blob; - struct rsa_public_key key; - const void *modulus, *rr; - const uint64_t *public_exponent; + struct key_prop prop; int length; - int ret;

if (node < 0) { debug("%s: Skipping invalid node", __func__); return -EBADF; } - if (!fdt_getprop(blob, node, "rsa,n0-inverse", NULL)) { - debug("%s: Missing rsa,n0-inverse", __func__); - return -EFAULT; - } - key.len = fdtdec_get_int(blob, node, "rsa,num-bits", 0); - key.n0inv = fdtdec_get_int(blob, node, "rsa,n0-inverse", 0); - public_exponent = fdt_getprop(blob, node, "rsa,exponent", &length); - if (!public_exponent || length < sizeof(*public_exponent)) - key.exponent = RSA_DEFAULT_PUBEXP; - else - key.exponent = fdt64_to_cpu(*public_exponent); - modulus = fdt_getprop(blob, node, "rsa,modulus", NULL); - rr = fdt_getprop(blob, node, "rsa,r-squared", NULL); - if (!key.len || !modulus || !rr) { - debug("%s: Missing RSA key info", __func__); - return -EFAULT; - }

- /* Sanity check for stack size */ - if (key.len > RSA_MAX_KEY_BITS || key.len < RSA_MIN_KEY_BITS) { - debug("RSA key bits %u outside allowed range %d..%d\n", - key.len, RSA_MIN_KEY_BITS, RSA_MAX_KEY_BITS); + prop.num_bits = fdtdec_get_int(blob, node, "rsa,num-bits", 0); + + prop.n0inv = fdtdec_get_int(blob, node, "rsa,n0-inverse", 0); + + prop.public_exponent = fdt_getprop(blob, node, "rsa,exponent", &length); + if (!prop.public_exponent || length < sizeof(uint64_t)) + prop.public_exponent = NULL; + + prop.exp_len = sizeof(uint64_t); + + prop.modulus = fdt_getprop(blob, node, "rsa,modulus", NULL); + + prop.rr = fdt_getprop(blob, node, "rsa,r-squared", NULL); + + if (!prop.num_bits || !prop.modulus) { + debug("%s: Missing RSA key info", __func__); return -EFAULT; } - key.len /= sizeof(uint32_t) * 8; - uint32_t key1[key.len], key2[key.len]; - - key.modulus = key1; - key.rr = key2; - rsa_convert_big_endian(key.modulus, modulus, key.len); - rsa_convert_big_endian(key.rr, rr, key.len); - if (!key.modulus || !key.rr) { - debug("%s: Out of memory", __func__); - return -ENOMEM; - }

- debug("key length %d\n", key.len); - ret = rsa_verify_key(&key, sig, sig_len, hash, info->algo->checksum); - if (ret) { - printf("%s: RSA failed to verify: %d\n", __func__, ret); - return ret; - } + rsa_verify_key(&prop, sig, sig_len, hash, info->algo->checksum);

return 0; + }

int rsa_verify(struct image_sign_info *info, diff --git a/tools/Makefile b/tools/Makefile index a4216a1..f67cd15 100644 --- a/tools/Makefile +++ b/tools/Makefile @@ -60,7 +60,7 @@ FIT_SIG_OBJS-$(CONFIG_FIT_SIGNATURE) := common/image-sig.o LIBFDT_OBJS := $(addprefix lib/libfdt/, \ fdt.o fdt_ro.o fdt_rw.o fdt_strerror.o fdt_wip.o) RSA_OBJS-$(CONFIG_FIT_SIGNATURE) := $(addprefix lib/rsa/, \ - rsa-sign.o rsa-verify.o rsa-checksum.o) + rsa-sign.o rsa-verify.o rsa-checksum.o rsa-mod-exp.o)

# common objs for dumpimage and mkimage dumpimage-mkimage-objs := aisimage.o \