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authorMartin Willi <martin@strongswan.org>2015-06-01 13:43:58 +0200
committerHerbert Xu <herbert@gondor.apana.org.au>2015-06-04 15:04:50 +0800
commitf979e014c50ce3f7467f133898dbea2243247a91 (patch)
treeb9b3bb455c76a9a94e3fcbe7fa9726890e083942 /crypto/poly1305_generic.c
parentcrypto: testmgr - Add ChaCha20 test vectors from RFC7539 (diff)
downloadlinux-dev-f979e014c50ce3f7467f133898dbea2243247a91.tar.xz
linux-dev-f979e014c50ce3f7467f133898dbea2243247a91.zip
crypto: poly1305 - Add a generic Poly1305 authenticator implementation
Poly1305 is a fast message authenticator designed by Daniel J. Bernstein. It is further defined in RFC7539 as a building block for the ChaCha20-Poly1305 AEAD for use in IETF protocols. This is a portable C implementation of the algorithm without architecture specific optimizations, based on public domain code by Daniel J. Bernstein and Andrew Moon. Signed-off-by: Martin Willi <martin@strongswan.org> Acked-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/poly1305_generic.c')
-rw-r--r--crypto/poly1305_generic.c300
1 files changed, 300 insertions, 0 deletions
diff --git a/crypto/poly1305_generic.c b/crypto/poly1305_generic.c
new file mode 100644
index 000000000000..9c1159b991f4
--- /dev/null
+++ b/crypto/poly1305_generic.c
@@ -0,0 +1,300 @@
+/*
+ * 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 <linux/crypto.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#define POLY1305_BLOCK_SIZE 16
+#define POLY1305_KEY_SIZE 32
+#define POLY1305_DIGEST_SIZE 16
+
+struct poly1305_ctx {
+ /* key */
+ u32 r[5];
+ /* finalize key */
+ u32 s[4];
+};
+
+struct poly1305_desc_ctx {
+ /* accumulator */
+ u32 h[5];
+ /* partial buffer */
+ u8 buf[POLY1305_BLOCK_SIZE];
+ /* bytes used in partial buffer */
+ unsigned int buflen;
+};
+
+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;
+}
+
+static inline u32 le32_to_cpuvp(const void *p)
+{
+ return le32_to_cpup(p);
+}
+
+static int 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;
+
+ return 0;
+}
+
+static int poly1305_setkey(struct crypto_shash *tfm,
+ const u8 *key, unsigned int keylen)
+{
+ struct poly1305_ctx *ctx = crypto_shash_ctx(tfm);
+
+ if (keylen != POLY1305_KEY_SIZE) {
+ crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
+ return -EINVAL;
+ }
+
+ /* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
+ ctx->r[0] = (le32_to_cpuvp(key + 0) >> 0) & 0x3ffffff;
+ ctx->r[1] = (le32_to_cpuvp(key + 3) >> 2) & 0x3ffff03;
+ ctx->r[2] = (le32_to_cpuvp(key + 6) >> 4) & 0x3ffc0ff;
+ ctx->r[3] = (le32_to_cpuvp(key + 9) >> 6) & 0x3f03fff;
+ ctx->r[4] = (le32_to_cpuvp(key + 12) >> 8) & 0x00fffff;
+
+ ctx->s[0] = le32_to_cpuvp(key + 16);
+ ctx->s[1] = le32_to_cpuvp(key + 20);
+ ctx->s[2] = le32_to_cpuvp(key + 24);
+ ctx->s[3] = le32_to_cpuvp(key + 28);
+
+ return 0;
+}
+
+static unsigned int poly1305_blocks(struct poly1305_desc_ctx *dctx,
+ struct poly1305_ctx *ctx, 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;
+
+ r0 = ctx->r[0];
+ r1 = ctx->r[1];
+ r2 = ctx->r[2];
+ r3 = ctx->r[3];
+ r4 = ctx->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 += (le32_to_cpuvp(src + 0) >> 0) & 0x3ffffff;
+ h1 += (le32_to_cpuvp(src + 3) >> 2) & 0x3ffffff;
+ h2 += (le32_to_cpuvp(src + 6) >> 4) & 0x3ffffff;
+ h3 += (le32_to_cpuvp(src + 9) >> 6) & 0x3ffffff;
+ h4 += (le32_to_cpuvp(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;
+}
+
+static int poly1305_update(struct shash_desc *desc,
+ const u8 *src, unsigned int srclen)
+{
+ struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
+ struct poly1305_ctx *ctx = crypto_shash_ctx(desc->tfm);
+ 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, ctx, dctx->buf,
+ POLY1305_BLOCK_SIZE, 1 << 24);
+ dctx->buflen = 0;
+ }
+ }
+
+ if (likely(srclen >= POLY1305_BLOCK_SIZE)) {
+ bytes = poly1305_blocks(dctx, ctx, src, srclen, 1 << 24);
+ src += srclen - bytes;
+ srclen = bytes;
+ }
+
+ if (unlikely(srclen)) {
+ dctx->buflen = srclen;
+ memcpy(dctx->buf, src, srclen);
+ }
+
+ return 0;
+}
+
+static int poly1305_final(struct shash_desc *desc, u8 *dst)
+{
+ struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
+ struct poly1305_ctx *ctx = crypto_shash_ctx(desc->tfm);
+ __le32 *mac = (__le32 *)dst;
+ u32 h0, h1, h2, h3, h4;
+ u32 g0, g1, g2, g3, g4;
+ u32 mask;
+ u64 f = 0;
+
+ if (unlikely(dctx->buflen)) {
+ dctx->buf[dctx->buflen++] = 1;
+ memset(dctx->buf + dctx->buflen, 0,
+ POLY1305_BLOCK_SIZE - dctx->buflen);
+ poly1305_blocks(dctx, ctx, 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 + ctx->s[0]; mac[0] = cpu_to_le32(f);
+ f = (f >> 32) + h1 + ctx->s[1]; mac[1] = cpu_to_le32(f);
+ f = (f >> 32) + h2 + ctx->s[2]; mac[2] = cpu_to_le32(f);
+ f = (f >> 32) + h3 + ctx->s[3]; mac[3] = cpu_to_le32(f);
+
+ return 0;
+}
+
+static struct shash_alg poly1305_alg = {
+ .digestsize = POLY1305_DIGEST_SIZE,
+ .init = poly1305_init,
+ .update = poly1305_update,
+ .final = poly1305_final,
+ .setkey = 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_ctxsize = sizeof(struct poly1305_ctx),
+ .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");