| /* |
| * Poly1305 authenticator algorithm, RFC7539 |
| * |
| * Copyright (C) 2015 Martin Willi |
| * |
| * Based on public domain code by Andrew Moon and Daniel J. Bernstein. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| */ |
| |
| #include <crypto/algapi.h> |
| #include <crypto/internal/hash.h> |
| #include <crypto/poly1305.h> |
| #include <linux/crypto.h> |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <asm/unaligned.h> |
| |
| static inline u64 mlt(u64 a, u64 b) |
| { |
| return a * b; |
| } |
| |
| static inline u32 sr(u64 v, u_char n) |
| { |
| return v >> n; |
| } |
| |
| static inline u32 and(u32 v, u32 mask) |
| { |
| return v & mask; |
| } |
| |
| int crypto_poly1305_init(struct shash_desc *desc) |
| { |
| struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc); |
| |
| memset(dctx->h, 0, sizeof(dctx->h)); |
| dctx->buflen = 0; |
| dctx->rset = false; |
| dctx->sset = false; |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(crypto_poly1305_init); |
| |
| int crypto_poly1305_setkey(struct crypto_shash *tfm, |
| const u8 *key, unsigned int keylen) |
| { |
| /* Poly1305 requires a unique key for each tag, which implies that |
| * we can't set it on the tfm that gets accessed by multiple users |
| * simultaneously. Instead we expect the key as the first 32 bytes in |
| * the update() call. */ |
| return -ENOTSUPP; |
| } |
| EXPORT_SYMBOL_GPL(crypto_poly1305_setkey); |
| |
| static void poly1305_setrkey(struct poly1305_desc_ctx *dctx, const u8 *key) |
| { |
| /* r &= 0xffffffc0ffffffc0ffffffc0fffffff */ |
| dctx->r[0] = (get_unaligned_le32(key + 0) >> 0) & 0x3ffffff; |
| dctx->r[1] = (get_unaligned_le32(key + 3) >> 2) & 0x3ffff03; |
| dctx->r[2] = (get_unaligned_le32(key + 6) >> 4) & 0x3ffc0ff; |
| dctx->r[3] = (get_unaligned_le32(key + 9) >> 6) & 0x3f03fff; |
| dctx->r[4] = (get_unaligned_le32(key + 12) >> 8) & 0x00fffff; |
| } |
| |
| static void poly1305_setskey(struct poly1305_desc_ctx *dctx, const u8 *key) |
| { |
| dctx->s[0] = get_unaligned_le32(key + 0); |
| dctx->s[1] = get_unaligned_le32(key + 4); |
| dctx->s[2] = get_unaligned_le32(key + 8); |
| dctx->s[3] = get_unaligned_le32(key + 12); |
| } |
| |
| unsigned int crypto_poly1305_setdesckey(struct poly1305_desc_ctx *dctx, |
| const u8 *src, unsigned int srclen) |
| { |
| if (!dctx->sset) { |
| if (!dctx->rset && srclen >= POLY1305_BLOCK_SIZE) { |
| poly1305_setrkey(dctx, src); |
| src += POLY1305_BLOCK_SIZE; |
| srclen -= POLY1305_BLOCK_SIZE; |
| dctx->rset = true; |
| } |
| if (srclen >= POLY1305_BLOCK_SIZE) { |
| poly1305_setskey(dctx, src); |
| src += POLY1305_BLOCK_SIZE; |
| srclen -= POLY1305_BLOCK_SIZE; |
| dctx->sset = true; |
| } |
| } |
| return srclen; |
| } |
| EXPORT_SYMBOL_GPL(crypto_poly1305_setdesckey); |
| |
| static unsigned int poly1305_blocks(struct poly1305_desc_ctx *dctx, |
| const u8 *src, unsigned int srclen, |
| u32 hibit) |
| { |
| u32 r0, r1, r2, r3, r4; |
| u32 s1, s2, s3, s4; |
| u32 h0, h1, h2, h3, h4; |
| u64 d0, d1, d2, d3, d4; |
| unsigned int datalen; |
| |
| if (unlikely(!dctx->sset)) { |
| datalen = crypto_poly1305_setdesckey(dctx, src, srclen); |
| src += srclen - datalen; |
| srclen = datalen; |
| } |
| |
| r0 = dctx->r[0]; |
| r1 = dctx->r[1]; |
| r2 = dctx->r[2]; |
| r3 = dctx->r[3]; |
| r4 = dctx->r[4]; |
| |
| s1 = r1 * 5; |
| s2 = r2 * 5; |
| s3 = r3 * 5; |
| s4 = r4 * 5; |
| |
| h0 = dctx->h[0]; |
| h1 = dctx->h[1]; |
| h2 = dctx->h[2]; |
| h3 = dctx->h[3]; |
| h4 = dctx->h[4]; |
| |
| while (likely(srclen >= POLY1305_BLOCK_SIZE)) { |
| |
| /* h += m[i] */ |
| h0 += (get_unaligned_le32(src + 0) >> 0) & 0x3ffffff; |
| h1 += (get_unaligned_le32(src + 3) >> 2) & 0x3ffffff; |
| h2 += (get_unaligned_le32(src + 6) >> 4) & 0x3ffffff; |
| h3 += (get_unaligned_le32(src + 9) >> 6) & 0x3ffffff; |
| h4 += (get_unaligned_le32(src + 12) >> 8) | hibit; |
| |
| /* h *= r */ |
| d0 = mlt(h0, r0) + mlt(h1, s4) + mlt(h2, s3) + |
| mlt(h3, s2) + mlt(h4, s1); |
| d1 = mlt(h0, r1) + mlt(h1, r0) + mlt(h2, s4) + |
| mlt(h3, s3) + mlt(h4, s2); |
| d2 = mlt(h0, r2) + mlt(h1, r1) + mlt(h2, r0) + |
| mlt(h3, s4) + mlt(h4, s3); |
| d3 = mlt(h0, r3) + mlt(h1, r2) + mlt(h2, r1) + |
| mlt(h3, r0) + mlt(h4, s4); |
| d4 = mlt(h0, r4) + mlt(h1, r3) + mlt(h2, r2) + |
| mlt(h3, r1) + mlt(h4, r0); |
| |
| /* (partial) h %= p */ |
| d1 += sr(d0, 26); h0 = and(d0, 0x3ffffff); |
| d2 += sr(d1, 26); h1 = and(d1, 0x3ffffff); |
| d3 += sr(d2, 26); h2 = and(d2, 0x3ffffff); |
| d4 += sr(d3, 26); h3 = and(d3, 0x3ffffff); |
| h0 += sr(d4, 26) * 5; h4 = and(d4, 0x3ffffff); |
| h1 += h0 >> 26; h0 = h0 & 0x3ffffff; |
| |
| src += POLY1305_BLOCK_SIZE; |
| srclen -= POLY1305_BLOCK_SIZE; |
| } |
| |
| dctx->h[0] = h0; |
| dctx->h[1] = h1; |
| dctx->h[2] = h2; |
| dctx->h[3] = h3; |
| dctx->h[4] = h4; |
| |
| return srclen; |
| } |
| |
| int crypto_poly1305_update(struct shash_desc *desc, |
| const u8 *src, unsigned int srclen) |
| { |
| struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc); |
| unsigned int bytes; |
| |
| if (unlikely(dctx->buflen)) { |
| bytes = min(srclen, POLY1305_BLOCK_SIZE - dctx->buflen); |
| memcpy(dctx->buf + dctx->buflen, src, bytes); |
| src += bytes; |
| srclen -= bytes; |
| dctx->buflen += bytes; |
| |
| if (dctx->buflen == POLY1305_BLOCK_SIZE) { |
| poly1305_blocks(dctx, dctx->buf, |
| POLY1305_BLOCK_SIZE, 1 << 24); |
| dctx->buflen = 0; |
| } |
| } |
| |
| if (likely(srclen >= POLY1305_BLOCK_SIZE)) { |
| bytes = poly1305_blocks(dctx, src, srclen, 1 << 24); |
| src += srclen - bytes; |
| srclen = bytes; |
| } |
| |
| if (unlikely(srclen)) { |
| dctx->buflen = srclen; |
| memcpy(dctx->buf, src, srclen); |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(crypto_poly1305_update); |
| |
| int crypto_poly1305_final(struct shash_desc *desc, u8 *dst) |
| { |
| struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc); |
| __le32 *mac = (__le32 *)dst; |
| u32 h0, h1, h2, h3, h4; |
| u32 g0, g1, g2, g3, g4; |
| u32 mask; |
| u64 f = 0; |
| |
| if (unlikely(!dctx->sset)) |
| return -ENOKEY; |
| |
| if (unlikely(dctx->buflen)) { |
| dctx->buf[dctx->buflen++] = 1; |
| memset(dctx->buf + dctx->buflen, 0, |
| POLY1305_BLOCK_SIZE - dctx->buflen); |
| poly1305_blocks(dctx, dctx->buf, POLY1305_BLOCK_SIZE, 0); |
| } |
| |
| /* fully carry h */ |
| h0 = dctx->h[0]; |
| h1 = dctx->h[1]; |
| h2 = dctx->h[2]; |
| h3 = dctx->h[3]; |
| h4 = dctx->h[4]; |
| |
| h2 += (h1 >> 26); h1 = h1 & 0x3ffffff; |
| h3 += (h2 >> 26); h2 = h2 & 0x3ffffff; |
| h4 += (h3 >> 26); h3 = h3 & 0x3ffffff; |
| h0 += (h4 >> 26) * 5; h4 = h4 & 0x3ffffff; |
| h1 += (h0 >> 26); h0 = h0 & 0x3ffffff; |
| |
| /* compute h + -p */ |
| g0 = h0 + 5; |
| g1 = h1 + (g0 >> 26); g0 &= 0x3ffffff; |
| g2 = h2 + (g1 >> 26); g1 &= 0x3ffffff; |
| g3 = h3 + (g2 >> 26); g2 &= 0x3ffffff; |
| g4 = h4 + (g3 >> 26) - (1 << 26); g3 &= 0x3ffffff; |
| |
| /* select h if h < p, or h + -p if h >= p */ |
| mask = (g4 >> ((sizeof(u32) * 8) - 1)) - 1; |
| g0 &= mask; |
| g1 &= mask; |
| g2 &= mask; |
| g3 &= mask; |
| g4 &= mask; |
| mask = ~mask; |
| h0 = (h0 & mask) | g0; |
| h1 = (h1 & mask) | g1; |
| h2 = (h2 & mask) | g2; |
| h3 = (h3 & mask) | g3; |
| h4 = (h4 & mask) | g4; |
| |
| /* h = h % (2^128) */ |
| h0 = (h0 >> 0) | (h1 << 26); |
| h1 = (h1 >> 6) | (h2 << 20); |
| h2 = (h2 >> 12) | (h3 << 14); |
| h3 = (h3 >> 18) | (h4 << 8); |
| |
| /* mac = (h + s) % (2^128) */ |
| f = (f >> 32) + h0 + dctx->s[0]; mac[0] = cpu_to_le32(f); |
| f = (f >> 32) + h1 + dctx->s[1]; mac[1] = cpu_to_le32(f); |
| f = (f >> 32) + h2 + dctx->s[2]; mac[2] = cpu_to_le32(f); |
| f = (f >> 32) + h3 + dctx->s[3]; mac[3] = cpu_to_le32(f); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(crypto_poly1305_final); |
| |
| static struct shash_alg poly1305_alg = { |
| .digestsize = POLY1305_DIGEST_SIZE, |
| .init = crypto_poly1305_init, |
| .update = crypto_poly1305_update, |
| .final = crypto_poly1305_final, |
| .setkey = crypto_poly1305_setkey, |
| .descsize = sizeof(struct poly1305_desc_ctx), |
| .base = { |
| .cra_name = "poly1305", |
| .cra_driver_name = "poly1305-generic", |
| .cra_priority = 100, |
| .cra_flags = CRYPTO_ALG_TYPE_SHASH, |
| .cra_alignmask = sizeof(u32) - 1, |
| .cra_blocksize = POLY1305_BLOCK_SIZE, |
| .cra_module = THIS_MODULE, |
| }, |
| }; |
| |
| static int __init poly1305_mod_init(void) |
| { |
| return crypto_register_shash(&poly1305_alg); |
| } |
| |
| static void __exit poly1305_mod_exit(void) |
| { |
| crypto_unregister_shash(&poly1305_alg); |
| } |
| |
| module_init(poly1305_mod_init); |
| module_exit(poly1305_mod_exit); |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Martin Willi <martin@strongswan.org>"); |
| MODULE_DESCRIPTION("Poly1305 authenticator"); |
| MODULE_ALIAS_CRYPTO("poly1305"); |
| MODULE_ALIAS_CRYPTO("poly1305-generic"); |