diff options
Diffstat (limited to 'tf-psa-crypto/drivers/builtin/src/ecdsa.c')
| -rw-r--r-- | tf-psa-crypto/drivers/builtin/src/ecdsa.c | 867 |
1 files changed, 867 insertions, 0 deletions
diff --git a/tf-psa-crypto/drivers/builtin/src/ecdsa.c b/tf-psa-crypto/drivers/builtin/src/ecdsa.c new file mode 100644 index 0000000..2f7a996 --- /dev/null +++ b/tf-psa-crypto/drivers/builtin/src/ecdsa.c @@ -0,0 +1,867 @@ +/* + * Elliptic curve DSA + * + * Copyright The Mbed TLS Contributors + * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later + */ + +/* + * References: + * + * SEC1 https://www.secg.org/sec1-v2.pdf + */ + +#include "common.h" + +#if defined(MBEDTLS_ECDSA_C) + +#include "mbedtls/ecdsa.h" +#include "mbedtls/asn1write.h" + +#include <string.h> + +#if defined(MBEDTLS_ECDSA_DETERMINISTIC) +#include "mbedtls/hmac_drbg.h" +#endif + +#include "mbedtls/platform.h" + +#include "mbedtls/platform_util.h" +#include "mbedtls/error.h" + +#if defined(MBEDTLS_ECP_RESTARTABLE) + +/* + * Sub-context for ecdsa_verify() + */ +struct mbedtls_ecdsa_restart_ver { + mbedtls_mpi u1, u2; /* intermediate values */ + enum { /* what to do next? */ + ecdsa_ver_init = 0, /* getting started */ + ecdsa_ver_muladd, /* muladd step */ + } state; +}; + +/* + * Init verify restart sub-context + */ +static void ecdsa_restart_ver_init(mbedtls_ecdsa_restart_ver_ctx *ctx) +{ + mbedtls_mpi_init(&ctx->u1); + mbedtls_mpi_init(&ctx->u2); + ctx->state = ecdsa_ver_init; +} + +/* + * Free the components of a verify restart sub-context + */ +static void ecdsa_restart_ver_free(mbedtls_ecdsa_restart_ver_ctx *ctx) +{ + if (ctx == NULL) { + return; + } + + mbedtls_mpi_free(&ctx->u1); + mbedtls_mpi_free(&ctx->u2); + + ecdsa_restart_ver_init(ctx); +} + +/* + * Sub-context for ecdsa_sign() + */ +struct mbedtls_ecdsa_restart_sig { + int sign_tries; + int key_tries; + mbedtls_mpi k; /* per-signature random */ + mbedtls_mpi r; /* r value */ + enum { /* what to do next? */ + ecdsa_sig_init = 0, /* getting started */ + ecdsa_sig_mul, /* doing ecp_mul() */ + ecdsa_sig_modn, /* mod N computations */ + } state; +}; + +/* + * Init verify sign sub-context + */ +static void ecdsa_restart_sig_init(mbedtls_ecdsa_restart_sig_ctx *ctx) +{ + ctx->sign_tries = 0; + ctx->key_tries = 0; + mbedtls_mpi_init(&ctx->k); + mbedtls_mpi_init(&ctx->r); + ctx->state = ecdsa_sig_init; +} + +/* + * Free the components of a sign restart sub-context + */ +static void ecdsa_restart_sig_free(mbedtls_ecdsa_restart_sig_ctx *ctx) +{ + if (ctx == NULL) { + return; + } + + mbedtls_mpi_free(&ctx->k); + mbedtls_mpi_free(&ctx->r); +} + +#if defined(MBEDTLS_ECDSA_DETERMINISTIC) +/* + * Sub-context for ecdsa_sign_det() + */ +struct mbedtls_ecdsa_restart_det { + mbedtls_hmac_drbg_context rng_ctx; /* DRBG state */ + enum { /* what to do next? */ + ecdsa_det_init = 0, /* getting started */ + ecdsa_det_sign, /* make signature */ + } state; +}; + +/* + * Init verify sign_det sub-context + */ +static void ecdsa_restart_det_init(mbedtls_ecdsa_restart_det_ctx *ctx) +{ + mbedtls_hmac_drbg_init(&ctx->rng_ctx); + ctx->state = ecdsa_det_init; +} + +/* + * Free the components of a sign_det restart sub-context + */ +static void ecdsa_restart_det_free(mbedtls_ecdsa_restart_det_ctx *ctx) +{ + if (ctx == NULL) { + return; + } + + mbedtls_hmac_drbg_free(&ctx->rng_ctx); + + ecdsa_restart_det_init(ctx); +} +#endif /* MBEDTLS_ECDSA_DETERMINISTIC */ + +#define ECDSA_RS_ECP (rs_ctx == NULL ? NULL : &rs_ctx->ecp) + +/* Utility macro for checking and updating ops budget */ +#define ECDSA_BUDGET(ops) \ + MBEDTLS_MPI_CHK(mbedtls_ecp_check_budget(grp, ECDSA_RS_ECP, ops)); + +/* Call this when entering a function that needs its own sub-context */ +#define ECDSA_RS_ENTER(SUB) do { \ + /* reset ops count for this call if top-level */ \ + if (rs_ctx != NULL && rs_ctx->ecp.depth++ == 0) \ + rs_ctx->ecp.ops_done = 0; \ + \ + /* set up our own sub-context if needed */ \ + if (mbedtls_ecp_restart_is_enabled() && \ + rs_ctx != NULL && rs_ctx->SUB == NULL) \ + { \ + rs_ctx->SUB = mbedtls_calloc(1, sizeof(*rs_ctx->SUB)); \ + if (rs_ctx->SUB == NULL) \ + return MBEDTLS_ERR_ECP_ALLOC_FAILED; \ + \ + ecdsa_restart_## SUB ##_init(rs_ctx->SUB); \ + } \ +} while (0) + +/* Call this when leaving a function that needs its own sub-context */ +#define ECDSA_RS_LEAVE(SUB) do { \ + /* clear our sub-context when not in progress (done or error) */ \ + if (rs_ctx != NULL && rs_ctx->SUB != NULL && \ + ret != MBEDTLS_ERR_ECP_IN_PROGRESS) \ + { \ + ecdsa_restart_## SUB ##_free(rs_ctx->SUB); \ + mbedtls_free(rs_ctx->SUB); \ + rs_ctx->SUB = NULL; \ + } \ + \ + if (rs_ctx != NULL) \ + rs_ctx->ecp.depth--; \ +} while (0) + +#else /* MBEDTLS_ECP_RESTARTABLE */ + +#define ECDSA_RS_ECP NULL + +#define ECDSA_BUDGET(ops) /* no-op; for compatibility */ + +#define ECDSA_RS_ENTER(SUB) (void) rs_ctx +#define ECDSA_RS_LEAVE(SUB) (void) rs_ctx + +#endif /* MBEDTLS_ECP_RESTARTABLE */ + +#if defined(MBEDTLS_ECDSA_DETERMINISTIC) || \ + !defined(MBEDTLS_ECDSA_SIGN_ALT) || \ + !defined(MBEDTLS_ECDSA_VERIFY_ALT) +/* + * Derive a suitable integer for group grp from a buffer of length len + * SEC1 4.1.3 step 5 aka SEC1 4.1.4 step 3 + */ +static int derive_mpi(const mbedtls_ecp_group *grp, mbedtls_mpi *x, + const unsigned char *buf, size_t blen) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t n_size = (grp->nbits + 7) / 8; + size_t use_size = blen > n_size ? n_size : blen; + + MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(x, buf, use_size)); + if (use_size * 8 > grp->nbits) { + MBEDTLS_MPI_CHK(mbedtls_mpi_shift_r(x, use_size * 8 - grp->nbits)); + } + + /* While at it, reduce modulo N */ + if (mbedtls_mpi_cmp_mpi(x, &grp->N) >= 0) { + MBEDTLS_MPI_CHK(mbedtls_mpi_sub_mpi(x, x, &grp->N)); + } + +cleanup: + return ret; +} +#endif /* ECDSA_DETERMINISTIC || !ECDSA_SIGN_ALT || !ECDSA_VERIFY_ALT */ + +int mbedtls_ecdsa_can_do(mbedtls_ecp_group_id gid) +{ + switch (gid) { +#ifdef MBEDTLS_ECP_DP_CURVE25519_ENABLED + case MBEDTLS_ECP_DP_CURVE25519: return 0; +#endif +#ifdef MBEDTLS_ECP_DP_CURVE448_ENABLED + case MBEDTLS_ECP_DP_CURVE448: return 0; +#endif + default: return 1; + } +} + +#if !defined(MBEDTLS_ECDSA_SIGN_ALT) +/* + * Compute ECDSA signature of a hashed message (SEC1 4.1.3) + * Obviously, compared to SEC1 4.1.3, we skip step 4 (hash message) + */ +int mbedtls_ecdsa_sign_restartable(mbedtls_ecp_group *grp, + mbedtls_mpi *r, mbedtls_mpi *s, + const mbedtls_mpi *d, const unsigned char *buf, size_t blen, + int (*f_rng)(void *, unsigned char *, size_t), void *p_rng, + int (*f_rng_blind)(void *, unsigned char *, size_t), + void *p_rng_blind, + mbedtls_ecdsa_restart_ctx *rs_ctx) +{ + int ret, key_tries, sign_tries; + int *p_sign_tries = &sign_tries, *p_key_tries = &key_tries; + mbedtls_ecp_point R; + mbedtls_mpi k, e, t; + mbedtls_mpi *pk = &k, *pr = r; + + /* Fail cleanly on curves such as Curve25519 that can't be used for ECDSA */ + if (!mbedtls_ecdsa_can_do(grp->id) || grp->N.p == NULL) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + /* Make sure d is in range 1..n-1 */ + if (mbedtls_mpi_cmp_int(d, 1) < 0 || mbedtls_mpi_cmp_mpi(d, &grp->N) >= 0) { + return MBEDTLS_ERR_ECP_INVALID_KEY; + } + + mbedtls_ecp_point_init(&R); + mbedtls_mpi_init(&k); mbedtls_mpi_init(&e); mbedtls_mpi_init(&t); + + ECDSA_RS_ENTER(sig); + +#if defined(MBEDTLS_ECP_RESTARTABLE) + if (rs_ctx != NULL && rs_ctx->sig != NULL) { + /* redirect to our context */ + p_sign_tries = &rs_ctx->sig->sign_tries; + p_key_tries = &rs_ctx->sig->key_tries; + pk = &rs_ctx->sig->k; + pr = &rs_ctx->sig->r; + + /* jump to current step */ + if (rs_ctx->sig->state == ecdsa_sig_mul) { + goto mul; + } + if (rs_ctx->sig->state == ecdsa_sig_modn) { + goto modn; + } + } +#endif /* MBEDTLS_ECP_RESTARTABLE */ + + *p_sign_tries = 0; + do { + if ((*p_sign_tries)++ > 10) { + ret = MBEDTLS_ERR_ECP_RANDOM_FAILED; + goto cleanup; + } + + /* + * Steps 1-3: generate a suitable ephemeral keypair + * and set r = xR mod n + */ + *p_key_tries = 0; + do { + if ((*p_key_tries)++ > 10) { + ret = MBEDTLS_ERR_ECP_RANDOM_FAILED; + goto cleanup; + } + + MBEDTLS_MPI_CHK(mbedtls_ecp_gen_privkey(grp, pk, f_rng, p_rng)); + +#if defined(MBEDTLS_ECP_RESTARTABLE) + if (rs_ctx != NULL && rs_ctx->sig != NULL) { + rs_ctx->sig->state = ecdsa_sig_mul; + } + +mul: +#endif + MBEDTLS_MPI_CHK(mbedtls_ecp_mul_restartable(grp, &R, pk, &grp->G, + f_rng_blind, + p_rng_blind, + ECDSA_RS_ECP)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(pr, &R.X, &grp->N)); + } while (mbedtls_mpi_cmp_int(pr, 0) == 0); + +#if defined(MBEDTLS_ECP_RESTARTABLE) + if (rs_ctx != NULL && rs_ctx->sig != NULL) { + rs_ctx->sig->state = ecdsa_sig_modn; + } + +modn: +#endif + /* + * Accounting for everything up to the end of the loop + * (step 6, but checking now avoids saving e and t) + */ + ECDSA_BUDGET(MBEDTLS_ECP_OPS_INV + 4); + + /* + * Step 5: derive MPI from hashed message + */ + MBEDTLS_MPI_CHK(derive_mpi(grp, &e, buf, blen)); + + /* + * Generate a random value to blind inv_mod in next step, + * avoiding a potential timing leak. + */ + MBEDTLS_MPI_CHK(mbedtls_ecp_gen_privkey(grp, &t, f_rng_blind, + p_rng_blind)); + + /* + * Step 6: compute s = (e + r * d) / k = t (e + rd) / (kt) mod n + */ + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(s, pr, d)); + MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi(&e, &e, s)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&e, &e, &t)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(pk, pk, &t)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(pk, pk, &grp->N)); + MBEDTLS_MPI_CHK(mbedtls_mpi_inv_mod(s, pk, &grp->N)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(s, s, &e)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(s, s, &grp->N)); + } while (mbedtls_mpi_cmp_int(s, 0) == 0); + +#if defined(MBEDTLS_ECP_RESTARTABLE) + if (rs_ctx != NULL && rs_ctx->sig != NULL) { + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(r, pr)); + } +#endif + +cleanup: + mbedtls_ecp_point_free(&R); + mbedtls_mpi_free(&k); mbedtls_mpi_free(&e); mbedtls_mpi_free(&t); + + ECDSA_RS_LEAVE(sig); + + return ret; +} + +/* + * Compute ECDSA signature of a hashed message + */ +int mbedtls_ecdsa_sign(mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s, + const mbedtls_mpi *d, const unsigned char *buf, size_t blen, + int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) +{ + /* Use the same RNG for both blinding and ephemeral key generation */ + return mbedtls_ecdsa_sign_restartable(grp, r, s, d, buf, blen, + f_rng, p_rng, f_rng, p_rng, NULL); +} +#endif /* !MBEDTLS_ECDSA_SIGN_ALT */ + +#if defined(MBEDTLS_ECDSA_DETERMINISTIC) +/* + * Deterministic signature wrapper + * + * note: The f_rng_blind parameter must not be NULL. + * + */ +int mbedtls_ecdsa_sign_det_restartable(mbedtls_ecp_group *grp, + mbedtls_mpi *r, mbedtls_mpi *s, + const mbedtls_mpi *d, const unsigned char *buf, size_t blen, + mbedtls_md_type_t md_alg, + int (*f_rng_blind)(void *, unsigned char *, size_t), + void *p_rng_blind, + mbedtls_ecdsa_restart_ctx *rs_ctx) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_hmac_drbg_context rng_ctx; + mbedtls_hmac_drbg_context *p_rng = &rng_ctx; + unsigned char data[2 * MBEDTLS_ECP_MAX_BYTES]; + size_t grp_len = (grp->nbits + 7) / 8; + const mbedtls_md_info_t *md_info; + mbedtls_mpi h; + + if ((md_info = mbedtls_md_info_from_type(md_alg)) == NULL) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + mbedtls_mpi_init(&h); + mbedtls_hmac_drbg_init(&rng_ctx); + + ECDSA_RS_ENTER(det); + +#if defined(MBEDTLS_ECP_RESTARTABLE) + if (rs_ctx != NULL && rs_ctx->det != NULL) { + /* redirect to our context */ + p_rng = &rs_ctx->det->rng_ctx; + + /* jump to current step */ + if (rs_ctx->det->state == ecdsa_det_sign) { + goto sign; + } + } +#endif /* MBEDTLS_ECP_RESTARTABLE */ + + /* Use private key and message hash (reduced) to initialize HMAC_DRBG */ + MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(d, data, grp_len)); + MBEDTLS_MPI_CHK(derive_mpi(grp, &h, buf, blen)); + MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&h, data + grp_len, grp_len)); + MBEDTLS_MPI_CHK(mbedtls_hmac_drbg_seed_buf(p_rng, md_info, data, 2 * grp_len)); + +#if defined(MBEDTLS_ECP_RESTARTABLE) + if (rs_ctx != NULL && rs_ctx->det != NULL) { + rs_ctx->det->state = ecdsa_det_sign; + } + +sign: +#endif +#if defined(MBEDTLS_ECDSA_SIGN_ALT) + (void) f_rng_blind; + (void) p_rng_blind; + ret = mbedtls_ecdsa_sign(grp, r, s, d, buf, blen, + mbedtls_hmac_drbg_random, p_rng); +#else + ret = mbedtls_ecdsa_sign_restartable(grp, r, s, d, buf, blen, + mbedtls_hmac_drbg_random, p_rng, + f_rng_blind, p_rng_blind, rs_ctx); +#endif /* MBEDTLS_ECDSA_SIGN_ALT */ + +cleanup: + mbedtls_hmac_drbg_free(&rng_ctx); + mbedtls_mpi_free(&h); + + ECDSA_RS_LEAVE(det); + + return ret; +} + +/* + * Deterministic signature wrapper + */ +int mbedtls_ecdsa_sign_det_ext(mbedtls_ecp_group *grp, mbedtls_mpi *r, + mbedtls_mpi *s, const mbedtls_mpi *d, + const unsigned char *buf, size_t blen, + mbedtls_md_type_t md_alg, + int (*f_rng_blind)(void *, unsigned char *, + size_t), + void *p_rng_blind) +{ + return mbedtls_ecdsa_sign_det_restartable(grp, r, s, d, buf, blen, md_alg, + f_rng_blind, p_rng_blind, NULL); +} +#endif /* MBEDTLS_ECDSA_DETERMINISTIC */ + +#if !defined(MBEDTLS_ECDSA_VERIFY_ALT) +/* + * Verify ECDSA signature of hashed message (SEC1 4.1.4) + * Obviously, compared to SEC1 4.1.3, we skip step 2 (hash message) + */ +int mbedtls_ecdsa_verify_restartable(mbedtls_ecp_group *grp, + const unsigned char *buf, size_t blen, + const mbedtls_ecp_point *Q, + const mbedtls_mpi *r, + const mbedtls_mpi *s, + mbedtls_ecdsa_restart_ctx *rs_ctx) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_mpi e, s_inv, u1, u2; + mbedtls_ecp_point R; + mbedtls_mpi *pu1 = &u1, *pu2 = &u2; + + mbedtls_ecp_point_init(&R); + mbedtls_mpi_init(&e); mbedtls_mpi_init(&s_inv); + mbedtls_mpi_init(&u1); mbedtls_mpi_init(&u2); + + /* Fail cleanly on curves such as Curve25519 that can't be used for ECDSA */ + if (!mbedtls_ecdsa_can_do(grp->id) || grp->N.p == NULL) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + ECDSA_RS_ENTER(ver); + +#if defined(MBEDTLS_ECP_RESTARTABLE) + if (rs_ctx != NULL && rs_ctx->ver != NULL) { + /* redirect to our context */ + pu1 = &rs_ctx->ver->u1; + pu2 = &rs_ctx->ver->u2; + + /* jump to current step */ + if (rs_ctx->ver->state == ecdsa_ver_muladd) { + goto muladd; + } + } +#endif /* MBEDTLS_ECP_RESTARTABLE */ + + /* + * Step 1: make sure r and s are in range 1..n-1 + */ + if (mbedtls_mpi_cmp_int(r, 1) < 0 || mbedtls_mpi_cmp_mpi(r, &grp->N) >= 0 || + mbedtls_mpi_cmp_int(s, 1) < 0 || mbedtls_mpi_cmp_mpi(s, &grp->N) >= 0) { + ret = MBEDTLS_ERR_ECP_VERIFY_FAILED; + goto cleanup; + } + + /* + * Step 3: derive MPI from hashed message + */ + MBEDTLS_MPI_CHK(derive_mpi(grp, &e, buf, blen)); + + /* + * Step 4: u1 = e / s mod n, u2 = r / s mod n + */ + ECDSA_BUDGET(MBEDTLS_ECP_OPS_CHK + MBEDTLS_ECP_OPS_INV + 2); + + MBEDTLS_MPI_CHK(mbedtls_mpi_inv_mod(&s_inv, s, &grp->N)); + + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(pu1, &e, &s_inv)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(pu1, pu1, &grp->N)); + + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(pu2, r, &s_inv)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(pu2, pu2, &grp->N)); + +#if defined(MBEDTLS_ECP_RESTARTABLE) + if (rs_ctx != NULL && rs_ctx->ver != NULL) { + rs_ctx->ver->state = ecdsa_ver_muladd; + } + +muladd: +#endif + /* + * Step 5: R = u1 G + u2 Q + */ + MBEDTLS_MPI_CHK(mbedtls_ecp_muladd_restartable(grp, + &R, pu1, &grp->G, pu2, Q, ECDSA_RS_ECP)); + + if (mbedtls_ecp_is_zero(&R)) { + ret = MBEDTLS_ERR_ECP_VERIFY_FAILED; + goto cleanup; + } + + /* + * Step 6: convert xR to an integer (no-op) + * Step 7: reduce xR mod n (gives v) + */ + MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&R.X, &R.X, &grp->N)); + + /* + * Step 8: check if v (that is, R.X) is equal to r + */ + if (mbedtls_mpi_cmp_mpi(&R.X, r) != 0) { + ret = MBEDTLS_ERR_ECP_VERIFY_FAILED; + goto cleanup; + } + +cleanup: + mbedtls_ecp_point_free(&R); + mbedtls_mpi_free(&e); mbedtls_mpi_free(&s_inv); + mbedtls_mpi_free(&u1); mbedtls_mpi_free(&u2); + + ECDSA_RS_LEAVE(ver); + + return ret; +} + +/* + * Verify ECDSA signature of hashed message + */ +int mbedtls_ecdsa_verify(mbedtls_ecp_group *grp, + const unsigned char *buf, size_t blen, + const mbedtls_ecp_point *Q, + const mbedtls_mpi *r, + const mbedtls_mpi *s) +{ + return mbedtls_ecdsa_verify_restartable(grp, buf, blen, Q, r, s, NULL); +} +#endif /* !MBEDTLS_ECDSA_VERIFY_ALT */ + +/* + * Convert a signature (given by context) to ASN.1 + */ +static int ecdsa_signature_to_asn1(const mbedtls_mpi *r, const mbedtls_mpi *s, + unsigned char *sig, size_t sig_size, + size_t *slen) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + unsigned char buf[MBEDTLS_ECDSA_MAX_LEN] = { 0 }; + unsigned char *p = buf + sizeof(buf); + size_t len = 0; + + MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_mpi(&p, buf, s)); + MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_mpi(&p, buf, r)); + + MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&p, buf, len)); + MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&p, buf, + MBEDTLS_ASN1_CONSTRUCTED | + MBEDTLS_ASN1_SEQUENCE)); + + if (len > sig_size) { + return MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL; + } + + memcpy(sig, p, len); + *slen = len; + + return 0; +} + +/* + * Compute and write signature + */ +int mbedtls_ecdsa_write_signature_restartable(mbedtls_ecdsa_context *ctx, + mbedtls_md_type_t md_alg, + const unsigned char *hash, size_t hlen, + unsigned char *sig, size_t sig_size, size_t *slen, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + mbedtls_ecdsa_restart_ctx *rs_ctx) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_mpi r, s; + if (f_rng == NULL) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + mbedtls_mpi_init(&r); + mbedtls_mpi_init(&s); + +#if defined(MBEDTLS_ECDSA_DETERMINISTIC) + MBEDTLS_MPI_CHK(mbedtls_ecdsa_sign_det_restartable(&ctx->grp, &r, &s, &ctx->d, + hash, hlen, md_alg, f_rng, + p_rng, rs_ctx)); +#else + (void) md_alg; + +#if defined(MBEDTLS_ECDSA_SIGN_ALT) + (void) rs_ctx; + + MBEDTLS_MPI_CHK(mbedtls_ecdsa_sign(&ctx->grp, &r, &s, &ctx->d, + hash, hlen, f_rng, p_rng)); +#else + /* Use the same RNG for both blinding and ephemeral key generation */ + MBEDTLS_MPI_CHK(mbedtls_ecdsa_sign_restartable(&ctx->grp, &r, &s, &ctx->d, + hash, hlen, f_rng, p_rng, f_rng, + p_rng, rs_ctx)); +#endif /* MBEDTLS_ECDSA_SIGN_ALT */ +#endif /* MBEDTLS_ECDSA_DETERMINISTIC */ + + MBEDTLS_MPI_CHK(ecdsa_signature_to_asn1(&r, &s, sig, sig_size, slen)); + +cleanup: + mbedtls_mpi_free(&r); + mbedtls_mpi_free(&s); + + return ret; +} + +/* + * Compute and write signature + */ +int mbedtls_ecdsa_write_signature(mbedtls_ecdsa_context *ctx, + mbedtls_md_type_t md_alg, + const unsigned char *hash, size_t hlen, + unsigned char *sig, size_t sig_size, size_t *slen, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng) +{ + return mbedtls_ecdsa_write_signature_restartable( + ctx, md_alg, hash, hlen, sig, sig_size, slen, + f_rng, p_rng, NULL); +} + +/* + * Read and check signature + */ +int mbedtls_ecdsa_read_signature(mbedtls_ecdsa_context *ctx, + const unsigned char *hash, size_t hlen, + const unsigned char *sig, size_t slen) +{ + return mbedtls_ecdsa_read_signature_restartable( + ctx, hash, hlen, sig, slen, NULL); +} + +/* + * Restartable read and check signature + */ +int mbedtls_ecdsa_read_signature_restartable(mbedtls_ecdsa_context *ctx, + const unsigned char *hash, size_t hlen, + const unsigned char *sig, size_t slen, + mbedtls_ecdsa_restart_ctx *rs_ctx) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + unsigned char *p = (unsigned char *) sig; + const unsigned char *end = sig + slen; + size_t len; + mbedtls_mpi r, s; + mbedtls_mpi_init(&r); + mbedtls_mpi_init(&s); + + if ((ret = mbedtls_asn1_get_tag(&p, end, &len, + MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) { + ret += MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + goto cleanup; + } + + if (p + len != end) { + ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_ECP_BAD_INPUT_DATA, + MBEDTLS_ERR_ASN1_LENGTH_MISMATCH); + goto cleanup; + } + + if ((ret = mbedtls_asn1_get_mpi(&p, end, &r)) != 0 || + (ret = mbedtls_asn1_get_mpi(&p, end, &s)) != 0) { + ret += MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + goto cleanup; + } +#if defined(MBEDTLS_ECDSA_VERIFY_ALT) + (void) rs_ctx; + + if ((ret = mbedtls_ecdsa_verify(&ctx->grp, hash, hlen, + &ctx->Q, &r, &s)) != 0) { + goto cleanup; + } +#else + if ((ret = mbedtls_ecdsa_verify_restartable(&ctx->grp, hash, hlen, + &ctx->Q, &r, &s, rs_ctx)) != 0) { + goto cleanup; + } +#endif /* MBEDTLS_ECDSA_VERIFY_ALT */ + + /* At this point we know that the buffer starts with a valid signature. + * Return 0 if the buffer just contains the signature, and a specific + * error code if the valid signature is followed by more data. */ + if (p != end) { + ret = MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH; + } + +cleanup: + mbedtls_mpi_free(&r); + mbedtls_mpi_free(&s); + + return ret; +} + +#if !defined(MBEDTLS_ECDSA_GENKEY_ALT) +/* + * Generate key pair + */ +int mbedtls_ecdsa_genkey(mbedtls_ecdsa_context *ctx, mbedtls_ecp_group_id gid, + int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) +{ + int ret = 0; + ret = mbedtls_ecp_group_load(&ctx->grp, gid); + if (ret != 0) { + return ret; + } + + return mbedtls_ecp_gen_keypair(&ctx->grp, &ctx->d, + &ctx->Q, f_rng, p_rng); +} +#endif /* !MBEDTLS_ECDSA_GENKEY_ALT */ + +/* + * Set context from an mbedtls_ecp_keypair + */ +int mbedtls_ecdsa_from_keypair(mbedtls_ecdsa_context *ctx, const mbedtls_ecp_keypair *key) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + if ((ret = mbedtls_ecp_group_copy(&ctx->grp, &key->grp)) != 0 || + (ret = mbedtls_mpi_copy(&ctx->d, &key->d)) != 0 || + (ret = mbedtls_ecp_copy(&ctx->Q, &key->Q)) != 0) { + mbedtls_ecdsa_free(ctx); + } + + return ret; +} + +/* + * Initialize context + */ +void mbedtls_ecdsa_init(mbedtls_ecdsa_context *ctx) +{ + mbedtls_ecp_keypair_init(ctx); +} + +/* + * Free context + */ +void mbedtls_ecdsa_free(mbedtls_ecdsa_context *ctx) +{ + if (ctx == NULL) { + return; + } + + mbedtls_ecp_keypair_free(ctx); +} + +#if defined(MBEDTLS_ECP_RESTARTABLE) +/* + * Initialize a restart context + */ +void mbedtls_ecdsa_restart_init(mbedtls_ecdsa_restart_ctx *ctx) +{ + mbedtls_ecp_restart_init(&ctx->ecp); + + ctx->ver = NULL; + ctx->sig = NULL; +#if defined(MBEDTLS_ECDSA_DETERMINISTIC) + ctx->det = NULL; +#endif +} + +/* + * Free the components of a restart context + */ +void mbedtls_ecdsa_restart_free(mbedtls_ecdsa_restart_ctx *ctx) +{ + if (ctx == NULL) { + return; + } + + mbedtls_ecp_restart_free(&ctx->ecp); + + ecdsa_restart_ver_free(ctx->ver); + mbedtls_free(ctx->ver); + ctx->ver = NULL; + + ecdsa_restart_sig_free(ctx->sig); + mbedtls_free(ctx->sig); + ctx->sig = NULL; + +#if defined(MBEDTLS_ECDSA_DETERMINISTIC) + ecdsa_restart_det_free(ctx->det); + mbedtls_free(ctx->det); + ctx->det = NULL; +#endif +} +#endif /* MBEDTLS_ECP_RESTARTABLE */ + +#endif /* MBEDTLS_ECDSA_C */ |