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a745d3ace3
Move ecc.h header file to 'include/crypto/internal' so that it can be easily imported from everywhere in the kernel tree. This change is done to allow crypto device drivers to re-use the symbols exported by 'crypto/ecc.c', thus avoiding code duplication. Signed-off-by: Daniele Alessandrelli <daniele.alessandrelli@intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
377 lines
9.2 KiB
C
377 lines
9.2 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (c) 2021 IBM Corporation
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*/
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#include <linux/module.h>
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#include <crypto/internal/akcipher.h>
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#include <crypto/internal/ecc.h>
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#include <crypto/akcipher.h>
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#include <crypto/ecdh.h>
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#include <linux/asn1_decoder.h>
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#include <linux/scatterlist.h>
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#include "ecdsasignature.asn1.h"
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struct ecc_ctx {
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unsigned int curve_id;
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const struct ecc_curve *curve;
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bool pub_key_set;
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u64 x[ECC_MAX_DIGITS]; /* pub key x and y coordinates */
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u64 y[ECC_MAX_DIGITS];
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struct ecc_point pub_key;
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};
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struct ecdsa_signature_ctx {
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const struct ecc_curve *curve;
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u64 r[ECC_MAX_DIGITS];
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u64 s[ECC_MAX_DIGITS];
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};
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/*
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* Get the r and s components of a signature from the X509 certificate.
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*/
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static int ecdsa_get_signature_rs(u64 *dest, size_t hdrlen, unsigned char tag,
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const void *value, size_t vlen, unsigned int ndigits)
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{
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size_t keylen = ndigits * sizeof(u64);
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ssize_t diff = vlen - keylen;
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const char *d = value;
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u8 rs[ECC_MAX_BYTES];
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if (!value || !vlen)
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return -EINVAL;
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/* diff = 0: 'value' has exacly the right size
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* diff > 0: 'value' has too many bytes; one leading zero is allowed that
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* makes the value a positive integer; error on more
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* diff < 0: 'value' is missing leading zeros, which we add
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*/
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if (diff > 0) {
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/* skip over leading zeros that make 'value' a positive int */
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if (*d == 0) {
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vlen -= 1;
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diff--;
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d++;
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}
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if (diff)
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return -EINVAL;
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}
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if (-diff >= keylen)
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return -EINVAL;
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if (diff) {
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/* leading zeros not given in 'value' */
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memset(rs, 0, -diff);
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}
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memcpy(&rs[-diff], d, vlen);
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ecc_swap_digits((u64 *)rs, dest, ndigits);
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return 0;
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}
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int ecdsa_get_signature_r(void *context, size_t hdrlen, unsigned char tag,
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const void *value, size_t vlen)
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{
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struct ecdsa_signature_ctx *sig = context;
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return ecdsa_get_signature_rs(sig->r, hdrlen, tag, value, vlen,
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sig->curve->g.ndigits);
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}
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int ecdsa_get_signature_s(void *context, size_t hdrlen, unsigned char tag,
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const void *value, size_t vlen)
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{
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struct ecdsa_signature_ctx *sig = context;
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return ecdsa_get_signature_rs(sig->s, hdrlen, tag, value, vlen,
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sig->curve->g.ndigits);
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}
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static int _ecdsa_verify(struct ecc_ctx *ctx, const u64 *hash, const u64 *r, const u64 *s)
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{
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const struct ecc_curve *curve = ctx->curve;
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unsigned int ndigits = curve->g.ndigits;
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u64 s1[ECC_MAX_DIGITS];
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u64 u1[ECC_MAX_DIGITS];
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u64 u2[ECC_MAX_DIGITS];
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u64 x1[ECC_MAX_DIGITS];
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u64 y1[ECC_MAX_DIGITS];
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struct ecc_point res = ECC_POINT_INIT(x1, y1, ndigits);
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/* 0 < r < n and 0 < s < n */
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if (vli_is_zero(r, ndigits) || vli_cmp(r, curve->n, ndigits) >= 0 ||
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vli_is_zero(s, ndigits) || vli_cmp(s, curve->n, ndigits) >= 0)
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return -EBADMSG;
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/* hash is given */
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pr_devel("hash : %016llx %016llx ... %016llx\n",
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hash[ndigits - 1], hash[ndigits - 2], hash[0]);
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/* s1 = (s^-1) mod n */
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vli_mod_inv(s1, s, curve->n, ndigits);
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/* u1 = (hash * s1) mod n */
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vli_mod_mult_slow(u1, hash, s1, curve->n, ndigits);
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/* u2 = (r * s1) mod n */
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vli_mod_mult_slow(u2, r, s1, curve->n, ndigits);
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/* res = u1*G + u2 * pub_key */
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ecc_point_mult_shamir(&res, u1, &curve->g, u2, &ctx->pub_key, curve);
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/* res.x = res.x mod n (if res.x > order) */
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if (unlikely(vli_cmp(res.x, curve->n, ndigits) == 1))
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/* faster alternative for NIST p384, p256 & p192 */
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vli_sub(res.x, res.x, curve->n, ndigits);
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if (!vli_cmp(res.x, r, ndigits))
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return 0;
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return -EKEYREJECTED;
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}
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/*
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* Verify an ECDSA signature.
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*/
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static int ecdsa_verify(struct akcipher_request *req)
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{
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struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
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struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm);
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size_t keylen = ctx->curve->g.ndigits * sizeof(u64);
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struct ecdsa_signature_ctx sig_ctx = {
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.curve = ctx->curve,
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};
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u8 rawhash[ECC_MAX_BYTES];
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u64 hash[ECC_MAX_DIGITS];
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unsigned char *buffer;
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ssize_t diff;
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int ret;
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if (unlikely(!ctx->pub_key_set))
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return -EINVAL;
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buffer = kmalloc(req->src_len + req->dst_len, GFP_KERNEL);
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if (!buffer)
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return -ENOMEM;
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sg_pcopy_to_buffer(req->src,
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sg_nents_for_len(req->src, req->src_len + req->dst_len),
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buffer, req->src_len + req->dst_len, 0);
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ret = asn1_ber_decoder(&ecdsasignature_decoder, &sig_ctx,
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buffer, req->src_len);
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if (ret < 0)
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goto error;
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/* if the hash is shorter then we will add leading zeros to fit to ndigits */
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diff = keylen - req->dst_len;
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if (diff >= 0) {
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if (diff)
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memset(rawhash, 0, diff);
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memcpy(&rawhash[diff], buffer + req->src_len, req->dst_len);
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} else if (diff < 0) {
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/* given hash is longer, we take the left-most bytes */
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memcpy(&rawhash, buffer + req->src_len, keylen);
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}
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ecc_swap_digits((u64 *)rawhash, hash, ctx->curve->g.ndigits);
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ret = _ecdsa_verify(ctx, hash, sig_ctx.r, sig_ctx.s);
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error:
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kfree(buffer);
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return ret;
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}
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static int ecdsa_ecc_ctx_init(struct ecc_ctx *ctx, unsigned int curve_id)
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{
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ctx->curve_id = curve_id;
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ctx->curve = ecc_get_curve(curve_id);
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if (!ctx->curve)
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return -EINVAL;
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return 0;
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}
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static void ecdsa_ecc_ctx_deinit(struct ecc_ctx *ctx)
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{
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ctx->pub_key_set = false;
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}
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static int ecdsa_ecc_ctx_reset(struct ecc_ctx *ctx)
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{
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unsigned int curve_id = ctx->curve_id;
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int ret;
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ecdsa_ecc_ctx_deinit(ctx);
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ret = ecdsa_ecc_ctx_init(ctx, curve_id);
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if (ret == 0)
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ctx->pub_key = ECC_POINT_INIT(ctx->x, ctx->y,
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ctx->curve->g.ndigits);
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return ret;
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}
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/*
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* Set the public key given the raw uncompressed key data from an X509
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* certificate. The key data contain the concatenated X and Y coordinates of
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* the public key.
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*/
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static int ecdsa_set_pub_key(struct crypto_akcipher *tfm, const void *key, unsigned int keylen)
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{
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struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm);
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const unsigned char *d = key;
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const u64 *digits = (const u64 *)&d[1];
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unsigned int ndigits;
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int ret;
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ret = ecdsa_ecc_ctx_reset(ctx);
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if (ret < 0)
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return ret;
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if (keylen < 1 || (((keylen - 1) >> 1) % sizeof(u64)) != 0)
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return -EINVAL;
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/* we only accept uncompressed format indicated by '4' */
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if (d[0] != 4)
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return -EINVAL;
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keylen--;
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ndigits = (keylen >> 1) / sizeof(u64);
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if (ndigits != ctx->curve->g.ndigits)
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return -EINVAL;
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ecc_swap_digits(digits, ctx->pub_key.x, ndigits);
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ecc_swap_digits(&digits[ndigits], ctx->pub_key.y, ndigits);
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ret = ecc_is_pubkey_valid_full(ctx->curve, &ctx->pub_key);
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ctx->pub_key_set = ret == 0;
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return ret;
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}
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static void ecdsa_exit_tfm(struct crypto_akcipher *tfm)
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{
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struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm);
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ecdsa_ecc_ctx_deinit(ctx);
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}
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static unsigned int ecdsa_max_size(struct crypto_akcipher *tfm)
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{
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struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm);
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return ctx->pub_key.ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
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}
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static int ecdsa_nist_p384_init_tfm(struct crypto_akcipher *tfm)
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{
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struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm);
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return ecdsa_ecc_ctx_init(ctx, ECC_CURVE_NIST_P384);
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}
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static struct akcipher_alg ecdsa_nist_p384 = {
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.verify = ecdsa_verify,
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.set_pub_key = ecdsa_set_pub_key,
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.max_size = ecdsa_max_size,
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.init = ecdsa_nist_p384_init_tfm,
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.exit = ecdsa_exit_tfm,
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.base = {
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.cra_name = "ecdsa-nist-p384",
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.cra_driver_name = "ecdsa-nist-p384-generic",
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.cra_priority = 100,
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.cra_module = THIS_MODULE,
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.cra_ctxsize = sizeof(struct ecc_ctx),
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},
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};
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static int ecdsa_nist_p256_init_tfm(struct crypto_akcipher *tfm)
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{
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struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm);
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return ecdsa_ecc_ctx_init(ctx, ECC_CURVE_NIST_P256);
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}
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static struct akcipher_alg ecdsa_nist_p256 = {
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.verify = ecdsa_verify,
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.set_pub_key = ecdsa_set_pub_key,
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.max_size = ecdsa_max_size,
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.init = ecdsa_nist_p256_init_tfm,
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.exit = ecdsa_exit_tfm,
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.base = {
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.cra_name = "ecdsa-nist-p256",
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.cra_driver_name = "ecdsa-nist-p256-generic",
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.cra_priority = 100,
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.cra_module = THIS_MODULE,
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.cra_ctxsize = sizeof(struct ecc_ctx),
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},
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};
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static int ecdsa_nist_p192_init_tfm(struct crypto_akcipher *tfm)
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{
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struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm);
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return ecdsa_ecc_ctx_init(ctx, ECC_CURVE_NIST_P192);
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}
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static struct akcipher_alg ecdsa_nist_p192 = {
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.verify = ecdsa_verify,
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.set_pub_key = ecdsa_set_pub_key,
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.max_size = ecdsa_max_size,
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.init = ecdsa_nist_p192_init_tfm,
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.exit = ecdsa_exit_tfm,
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.base = {
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.cra_name = "ecdsa-nist-p192",
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.cra_driver_name = "ecdsa-nist-p192-generic",
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.cra_priority = 100,
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.cra_module = THIS_MODULE,
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.cra_ctxsize = sizeof(struct ecc_ctx),
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},
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};
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static bool ecdsa_nist_p192_registered;
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static int ecdsa_init(void)
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{
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int ret;
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/* NIST p192 may not be available in FIPS mode */
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ret = crypto_register_akcipher(&ecdsa_nist_p192);
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ecdsa_nist_p192_registered = ret == 0;
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ret = crypto_register_akcipher(&ecdsa_nist_p256);
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if (ret)
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goto nist_p256_error;
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ret = crypto_register_akcipher(&ecdsa_nist_p384);
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if (ret)
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goto nist_p384_error;
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return 0;
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nist_p384_error:
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crypto_unregister_akcipher(&ecdsa_nist_p256);
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nist_p256_error:
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if (ecdsa_nist_p192_registered)
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crypto_unregister_akcipher(&ecdsa_nist_p192);
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return ret;
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}
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static void ecdsa_exit(void)
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{
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if (ecdsa_nist_p192_registered)
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crypto_unregister_akcipher(&ecdsa_nist_p192);
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crypto_unregister_akcipher(&ecdsa_nist_p256);
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crypto_unregister_akcipher(&ecdsa_nist_p384);
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}
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subsys_initcall(ecdsa_init);
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module_exit(ecdsa_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Stefan Berger <stefanb@linux.ibm.com>");
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MODULE_DESCRIPTION("ECDSA generic algorithm");
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MODULE_ALIAS_CRYPTO("ecdsa-generic");
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