X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=lib%2Frsa%2Frsa-verify.c;h=0d548f8b8f93deaa313a338df0f011b234998929;hb=f844d5f4e6bd97c3a4a39e180b5efa8b0b0abd56;hp=bcb906368d0dc273eb462a023a8d0477f2c51795;hpb=ed1d98d801dfb6384d0f2fff45ce1ebf884944ca;p=oweals%2Fu-boot.git diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c index bcb906368d..0d548f8b8f 100644 --- a/lib/rsa/rsa-verify.c +++ b/lib/rsa/rsa-verify.c @@ -9,173 +9,83 @@ #include #include #include -#include +#include #include #include +#include #else #include "fdt_host.h" #include "mkimage.h" #include #endif +#include #include -#include -#include -#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 + * rsa_verify_padding() - Verify RSA message padding is valid * - * @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 + * Verify a RSA message's padding is consistent with PKCS1.5 + * padding as described in the RSA PKCS#1 v2.1 standard. * - * @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 + * @msg: Padded message + * @pad_len: Number of expected padding bytes + * @algo: Checksum algo structure having information on DER encoding etc. + * @return 0 on success, != 0 on failure */ -static int greater_equal_modulus(const struct rsa_public_key *key, - uint32_t num[]) +static int rsa_verify_padding(const uint8_t *msg, const int pad_len, + struct checksum_algo *algo) { - uint32_t i; - - for (i = 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); + int ff_len; + int ret; - result[i - 1] = (uint32_t)acc_a; + /* first byte must be 0x00 */ + ret = *msg++; + /* second byte must be 0x01 */ + ret |= *msg++ ^ 0x01; + /* next ff_len bytes must be 0xff */ + ff_len = pad_len - algo->der_len - 3; + ret |= *msg ^ 0xff; + ret |= memcmp(msg, msg+1, ff_len-1); + msg += ff_len; + /* next byte must be 0x00 */ + ret |= *msg++; + /* next der_len bytes must match der_prefix */ + ret |= memcmp(msg, algo->der_prefix, algo->der_len); - if (acc_a >> 32) - subtract_modulus(key, result); + return ret; } /** - * montgomery_mul() - Perform montgomery mutitply - * - * Operation: montgomery result[] = a[] * b[] / n0inv % modulus + * rsa_verify_key() - Verify a signature against some data using RSA Key * - * @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); -} - -/** - * pow_mod() - in-place public exponentiation + * Verify a RSA PKCS1.5 signature against an expected hash using + * the RSA Key properties in prop structure. * - * @key: RSA key - * @inout: Big-endian word array containing value and result + * @prop: Specifies key + * @sig: Signature + * @sig_len: Number of bytes in signature + * @hash: Pointer to the expected hash + * @key_len: Number of bytes in rsa key + * @algo: Checksum algo structure having information on DER encoding etc. + * @return 0 if verified, -ve on error */ -static int pow_mod(const struct rsa_public_key *key, uint32_t *inout) -{ - uint32_t *result, *ptr; - uint i; - - /* 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]; - 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); - - montgomery_mul(key, acc, val, key->rr); /* axx = a * RR / R mod M */ - for (i = 0; i < 16; i += 2) { - montgomery_mul(key, tmp, acc, acc); /* tmp = acc^2 / R mod M */ - montgomery_mul(key, acc, tmp, tmp); /* acc = tmp^2 / R mod M */ - } - montgomery_mul(key, result, acc, val); /* result = XX * a / R mod M */ - - /* 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 *prop, const uint8_t *sig, const uint32_t sig_len, const uint8_t *hash, - struct checksum_algo *algo) + const uint32_t key_len, struct checksum_algo *algo) { - const uint8_t *padding; int pad_len; int ret; +#if !defined(USE_HOSTCC) + struct udevice *mod_exp_dev; +#endif - if (!key || !sig || !hash || !algo) + if (!prop || !sig || !hash || !algo) return -EIO; - if (sig_len != (key->len * sizeof(uint32_t))) { + if (sig_len != (prop->num_bits / 8)) { debug("Signature is of incorrect length %d\n", sig_len); return -EINVAL; } @@ -189,19 +99,29 @@ 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)]; + uint8_t buf[sig_len]; - memcpy(buf, sig, sig_len); +#if !defined(USE_HOSTCC) + ret = uclass_get_device(UCLASS_MOD_EXP, 0, &mod_exp_dev); + if (ret) { + printf("RSA: Can't find Modular Exp implementation\n"); + return -EINVAL; + } - ret = pow_mod(key, buf); - if (ret) + ret = rsa_mod_exp(mod_exp_dev, sig, sig_len, prop, buf); +#else + ret = rsa_mod_exp_sw(sig, sig_len, prop, buf); +#endif + if (ret) { + debug("Error in Modular exponentation\n"); return ret; + } - padding = algo->rsa_padding; - pad_len = algo->pad_len - algo->checksum_len; + pad_len = key_len - algo->checksum_len; /* Check pkcs1.5 padding bytes. */ - if (memcmp(buf, padding, pad_len)) { + ret = rsa_verify_padding(buf, pad_len, algo); + if (ret) { debug("In RSAVerify(): Padding check failed!\n"); return -EINVAL; } @@ -215,65 +135,58 @@ 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]); -} - +/** + * rsa_verify_with_keynode() - Verify a signature against some data using + * information in node with prperties of RSA Key like modulus, exponent etc. + * + * Parse sign-node and fill a key_prop structure with properties of the + * key. Verify a RSA PKCS1.5 signature against an expected hash using + * the properties parsed + * + * @info: Specifies key and FIT information + * @hash: Pointer to the expected hash + * @sig: Signature + * @sig_len: Number of bytes in signature + * @node: Node having the RSA Key properties + * @return 0 if verified, -ve on error + */ 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; - int ret; + struct key_prop prop; + int length; + int ret = 0; 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); - 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; - } + ret = rsa_verify_key(&prop, sig, sig_len, hash, + info->crypto->key_len, info->checksum); - return 0; + return ret; } int rsa_verify(struct image_sign_info *info, @@ -282,7 +195,7 @@ int rsa_verify(struct image_sign_info *info, { const void *blob = info->fdt_blob; /* Reserve memory for maximum checksum-length */ - uint8_t hash[info->algo->checksum->pad_len]; + uint8_t hash[info->crypto->key_len]; int ndepth, noffset; int sig_node, node; char name[100]; @@ -292,10 +205,10 @@ int rsa_verify(struct image_sign_info *info, * Verify that the checksum-length does not exceed the * rsa-signature-length */ - if (info->algo->checksum->checksum_len > - info->algo->checksum->pad_len) { + if (info->checksum->checksum_len > + info->crypto->key_len) { debug("%s: invlaid checksum-algorithm %s for %s\n", - __func__, info->algo->checksum->name, info->algo->name); + __func__, info->checksum->name, info->crypto->name); return -EINVAL; } @@ -306,7 +219,12 @@ int rsa_verify(struct image_sign_info *info, } /* Calculate checksum with checksum-algorithm */ - info->algo->checksum->calculate(region, region_count, hash); + ret = info->checksum->calculate(info->checksum->name, + region, region_count, hash); + if (ret < 0) { + debug("%s: Error in checksum calculation\n", __func__); + return -EINVAL; + } /* See if we must use a particular key */ if (info->required_keynode != -1) {