From 665ab7d9266b9979b4c4aa5f8a9cc87974f1ab65 Mon Sep 17 00:00:00 2001 From: tedu Date: Wed, 8 Jan 2014 05:00:01 +0000 Subject: [PATCH] allow building a VERIFYONLY version that's considerably smaller. most of the savings comes from eliminating the large constant table in ge25519.c. ok deraadt --- usr.bin/signify/Makefile | 5 +- usr.bin/signify/mod_ed25519.c | 143 +++++++++++++++ usr.bin/signify/mod_ge25519.c | 325 ++++++++++++++++++++++++++++++++++ usr.bin/signify/signify.c | 17 +- 4 files changed, 484 insertions(+), 6 deletions(-) create mode 100644 usr.bin/signify/mod_ed25519.c create mode 100644 usr.bin/signify/mod_ge25519.c diff --git a/usr.bin/signify/Makefile b/usr.bin/signify/Makefile index aca7b57b528..7dd8ebd3547 100644 --- a/usr.bin/signify/Makefile +++ b/usr.bin/signify/Makefile @@ -1,10 +1,11 @@ -# $OpenBSD: Makefile,v 1.2 2014/01/08 03:59:46 tedu Exp $ +# $OpenBSD: Makefile,v 1.3 2014/01/08 05:00:01 tedu Exp $ .PATH: ${.CURDIR}/../ssh CPPFLAGS += -I${.CURDIR}/../ssh SRCS= signify.c -SRCS+= ed25519.c fe25519.c ge25519.c sc25519.c smult_curve25519_ref.c +SRCS+= fe25519.c sc25519.c smult_curve25519_ref.c +SRCS+= mod_ed25519.c mod_ge25519.c SRCS+= crypto_api.c PROG= signify diff --git a/usr.bin/signify/mod_ed25519.c b/usr.bin/signify/mod_ed25519.c new file mode 100644 index 00000000000..aac481af7c5 --- /dev/null +++ b/usr.bin/signify/mod_ed25519.c @@ -0,0 +1,143 @@ +/* $OpenBSD: mod_ed25519.c,v 1.1 2014/01/08 05:00:01 tedu Exp $ */ + +/* + * Public Domain, Authors: Daniel J. Bernstein, Niels Duif, Tanja Lange, + * Peter Schwabe, Bo-Yin Yang. + * Copied from supercop-20130419/crypto_sign/ed25519/ref/ed25519.c + */ + +#include "crypto_api.h" + +#include "ge25519.h" + +static void get_hram(unsigned char *hram, const unsigned char *sm, const unsigned char *pk, unsigned char *playground, unsigned long long smlen) +{ + unsigned long long i; + + for (i = 0;i < 32;++i) playground[i] = sm[i]; + for (i = 32;i < 64;++i) playground[i] = pk[i-32]; + for (i = 64;i < smlen;++i) playground[i] = sm[i]; + + crypto_hash_sha512(hram,playground,smlen); +} + +#ifndef VERIFYONLY +int crypto_sign_ed25519_keypair( + unsigned char *pk, + unsigned char *sk + ) +{ + sc25519 scsk; + ge25519 gepk; + unsigned char extsk[64]; + int i; + + randombytes(sk, 32); + crypto_hash_sha512(extsk, sk, 32); + extsk[0] &= 248; + extsk[31] &= 127; + extsk[31] |= 64; + + sc25519_from32bytes(&scsk,extsk); + + ge25519_scalarmult_base(&gepk, &scsk); + ge25519_pack(pk, &gepk); + for(i=0;i<32;i++) + sk[32 + i] = pk[i]; + return 0; +} + +int crypto_sign_ed25519( + unsigned char *sm,unsigned long long *smlen, + const unsigned char *m,unsigned long long mlen, + const unsigned char *sk + ) +{ + sc25519 sck, scs, scsk; + ge25519 ger; + unsigned char r[32]; + unsigned char s[32]; + unsigned char extsk[64]; + unsigned long long i; + unsigned char hmg[crypto_hash_sha512_BYTES]; + unsigned char hram[crypto_hash_sha512_BYTES]; + + crypto_hash_sha512(extsk, sk, 32); + extsk[0] &= 248; + extsk[31] &= 127; + extsk[31] |= 64; + + *smlen = mlen+64; + for(i=0;ix, &p->x, &p->t); + fe25519_mul(&r->y, &p->y, &p->z); + fe25519_mul(&r->z, &p->z, &p->t); +} + +static void p1p1_to_p3(ge25519_p3 *r, const ge25519_p1p1 *p) +{ + p1p1_to_p2((ge25519_p2 *)r, p); + fe25519_mul(&r->t, &p->x, &p->y); +} + +static void ge25519_mixadd2(ge25519_p3 *r, const ge25519_aff *q) +{ + fe25519 a,b,t1,t2,c,d,e,f,g,h,qt; + fe25519_mul(&qt, &q->x, &q->y); + fe25519_sub(&a, &r->y, &r->x); /* A = (Y1-X1)*(Y2-X2) */ + fe25519_add(&b, &r->y, &r->x); /* B = (Y1+X1)*(Y2+X2) */ + fe25519_sub(&t1, &q->y, &q->x); + fe25519_add(&t2, &q->y, &q->x); + fe25519_mul(&a, &a, &t1); + fe25519_mul(&b, &b, &t2); + fe25519_sub(&e, &b, &a); /* E = B-A */ + fe25519_add(&h, &b, &a); /* H = B+A */ + fe25519_mul(&c, &r->t, &qt); /* C = T1*k*T2 */ + fe25519_mul(&c, &c, &ge25519_ec2d); + fe25519_add(&d, &r->z, &r->z); /* D = Z1*2 */ + fe25519_sub(&f, &d, &c); /* F = D-C */ + fe25519_add(&g, &d, &c); /* G = D+C */ + fe25519_mul(&r->x, &e, &f); + fe25519_mul(&r->y, &h, &g); + fe25519_mul(&r->z, &g, &f); + fe25519_mul(&r->t, &e, &h); +} + +static void add_p1p1(ge25519_p1p1 *r, const ge25519_p3 *p, const ge25519_p3 *q) +{ + fe25519 a, b, c, d, t; + + fe25519_sub(&a, &p->y, &p->x); /* A = (Y1-X1)*(Y2-X2) */ + fe25519_sub(&t, &q->y, &q->x); + fe25519_mul(&a, &a, &t); + fe25519_add(&b, &p->x, &p->y); /* B = (Y1+X1)*(Y2+X2) */ + fe25519_add(&t, &q->x, &q->y); + fe25519_mul(&b, &b, &t); + fe25519_mul(&c, &p->t, &q->t); /* C = T1*k*T2 */ + fe25519_mul(&c, &c, &ge25519_ec2d); + fe25519_mul(&d, &p->z, &q->z); /* D = Z1*2*Z2 */ + fe25519_add(&d, &d, &d); + fe25519_sub(&r->x, &b, &a); /* E = B-A */ + fe25519_sub(&r->t, &d, &c); /* F = D-C */ + fe25519_add(&r->z, &d, &c); /* G = D+C */ + fe25519_add(&r->y, &b, &a); /* H = B+A */ +} + +/* See http://www.hyperelliptic.org/EFD/g1p/auto-twisted-extended-1.html#doubling-dbl-2008-hwcd */ +static void dbl_p1p1(ge25519_p1p1 *r, const ge25519_p2 *p) +{ + fe25519 a,b,c,d; + fe25519_square(&a, &p->x); + fe25519_square(&b, &p->y); + fe25519_square(&c, &p->z); + fe25519_add(&c, &c, &c); + fe25519_neg(&d, &a); + + fe25519_add(&r->x, &p->x, &p->y); + fe25519_square(&r->x, &r->x); + fe25519_sub(&r->x, &r->x, &a); + fe25519_sub(&r->x, &r->x, &b); + fe25519_add(&r->z, &d, &b); + fe25519_sub(&r->t, &r->z, &c); + fe25519_sub(&r->y, &d, &b); +} + +/* Constant-time version of: if(b) r = p */ +static void cmov_aff(ge25519_aff *r, const ge25519_aff *p, unsigned char b) +{ + fe25519_cmov(&r->x, &p->x, b); + fe25519_cmov(&r->y, &p->y, b); +} + +static unsigned char equal(signed char b,signed char c) +{ + unsigned char ub = b; + unsigned char uc = c; + unsigned char x = ub ^ uc; /* 0: yes; 1..255: no */ + crypto_uint32 y = x; /* 0: yes; 1..255: no */ + y -= 1; /* 4294967295: yes; 0..254: no */ + y >>= 31; /* 1: yes; 0: no */ + return y; +} + +static unsigned char negative(signed char b) +{ + unsigned long long x = b; /* 18446744073709551361..18446744073709551615: yes; 0..255: no */ + x >>= 63; /* 1: yes; 0: no */ + return x; +} + +#ifndef VERIFYONLY +static void choose_t(ge25519_aff *t, unsigned long long pos, signed char b) +{ + /* constant time */ + fe25519 v; + *t = ge25519_base_multiples_affine[5*pos+0]; + cmov_aff(t, &ge25519_base_multiples_affine[5*pos+1],equal(b,1) | equal(b,-1)); + cmov_aff(t, &ge25519_base_multiples_affine[5*pos+2],equal(b,2) | equal(b,-2)); + cmov_aff(t, &ge25519_base_multiples_affine[5*pos+3],equal(b,3) | equal(b,-3)); + cmov_aff(t, &ge25519_base_multiples_affine[5*pos+4],equal(b,-4)); + fe25519_neg(&v, &t->x); + fe25519_cmov(&t->x, &v, negative(b)); +} +#endif + +static void setneutral(ge25519 *r) +{ + fe25519_setzero(&r->x); + fe25519_setone(&r->y); + fe25519_setone(&r->z); + fe25519_setzero(&r->t); +} + +/* ******************************************************************** + * EXPORTED FUNCTIONS + ******************************************************************** */ + +/* return 0 on success, -1 otherwise */ +int ge25519_unpackneg_vartime(ge25519_p3 *r, const unsigned char p[32]) +{ + unsigned char par; + fe25519 t, chk, num, den, den2, den4, den6; + fe25519_setone(&r->z); + par = p[31] >> 7; + fe25519_unpack(&r->y, p); + fe25519_square(&num, &r->y); /* x = y^2 */ + fe25519_mul(&den, &num, &ge25519_ecd); /* den = dy^2 */ + fe25519_sub(&num, &num, &r->z); /* x = y^2-1 */ + fe25519_add(&den, &r->z, &den); /* den = dy^2+1 */ + + /* Computation of sqrt(num/den) */ + /* 1.: computation of num^((p-5)/8)*den^((7p-35)/8) = (num*den^7)^((p-5)/8) */ + fe25519_square(&den2, &den); + fe25519_square(&den4, &den2); + fe25519_mul(&den6, &den4, &den2); + fe25519_mul(&t, &den6, &num); + fe25519_mul(&t, &t, &den); + + fe25519_pow2523(&t, &t); + /* 2. computation of r->x = t * num * den^3 */ + fe25519_mul(&t, &t, &num); + fe25519_mul(&t, &t, &den); + fe25519_mul(&t, &t, &den); + fe25519_mul(&r->x, &t, &den); + + /* 3. Check whether sqrt computation gave correct result, multiply by sqrt(-1) if not: */ + fe25519_square(&chk, &r->x); + fe25519_mul(&chk, &chk, &den); + if (!fe25519_iseq_vartime(&chk, &num)) + fe25519_mul(&r->x, &r->x, &ge25519_sqrtm1); + + /* 4. Now we have one of the two square roots, except if input was not a square */ + fe25519_square(&chk, &r->x); + fe25519_mul(&chk, &chk, &den); + if (!fe25519_iseq_vartime(&chk, &num)) + return -1; + + /* 5. Choose the desired square root according to parity: */ + if(fe25519_getparity(&r->x) != (1-par)) + fe25519_neg(&r->x, &r->x); + + fe25519_mul(&r->t, &r->x, &r->y); + return 0; +} + +void ge25519_pack(unsigned char r[32], const ge25519_p3 *p) +{ + fe25519 tx, ty, zi; + fe25519_invert(&zi, &p->z); + fe25519_mul(&tx, &p->x, &zi); + fe25519_mul(&ty, &p->y, &zi); + fe25519_pack(r, &ty); + r[31] ^= fe25519_getparity(&tx) << 7; +} + +int ge25519_isneutral_vartime(const ge25519_p3 *p) +{ + int ret = 1; + if(!fe25519_iszero(&p->x)) ret = 0; + if(!fe25519_iseq_vartime(&p->y, &p->z)) ret = 0; + return ret; +} + +/* computes [s1]p1 + [s2]p2 */ +void ge25519_double_scalarmult_vartime(ge25519_p3 *r, const ge25519_p3 *p1, const sc25519 *s1, const ge25519_p3 *p2, const sc25519 *s2) +{ + ge25519_p1p1 tp1p1; + ge25519_p3 pre[16]; + unsigned char b[127]; + int i; + + /* precomputation s2 s1 */ + setneutral(pre); /* 00 00 */ + pre[1] = *p1; /* 00 01 */ + dbl_p1p1(&tp1p1,(ge25519_p2 *)p1); p1p1_to_p3( &pre[2], &tp1p1); /* 00 10 */ + add_p1p1(&tp1p1,&pre[1], &pre[2]); p1p1_to_p3( &pre[3], &tp1p1); /* 00 11 */ + pre[4] = *p2; /* 01 00 */ + add_p1p1(&tp1p1,&pre[1], &pre[4]); p1p1_to_p3( &pre[5], &tp1p1); /* 01 01 */ + add_p1p1(&tp1p1,&pre[2], &pre[4]); p1p1_to_p3( &pre[6], &tp1p1); /* 01 10 */ + add_p1p1(&tp1p1,&pre[3], &pre[4]); p1p1_to_p3( &pre[7], &tp1p1); /* 01 11 */ + dbl_p1p1(&tp1p1,(ge25519_p2 *)p2); p1p1_to_p3( &pre[8], &tp1p1); /* 10 00 */ + add_p1p1(&tp1p1,&pre[1], &pre[8]); p1p1_to_p3( &pre[9], &tp1p1); /* 10 01 */ + dbl_p1p1(&tp1p1,(ge25519_p2 *)&pre[5]); p1p1_to_p3(&pre[10], &tp1p1); /* 10 10 */ + add_p1p1(&tp1p1,&pre[3], &pre[8]); p1p1_to_p3(&pre[11], &tp1p1); /* 10 11 */ + add_p1p1(&tp1p1,&pre[4], &pre[8]); p1p1_to_p3(&pre[12], &tp1p1); /* 11 00 */ + add_p1p1(&tp1p1,&pre[1],&pre[12]); p1p1_to_p3(&pre[13], &tp1p1); /* 11 01 */ + add_p1p1(&tp1p1,&pre[2],&pre[12]); p1p1_to_p3(&pre[14], &tp1p1); /* 11 10 */ + add_p1p1(&tp1p1,&pre[3],&pre[12]); p1p1_to_p3(&pre[15], &tp1p1); /* 11 11 */ + + sc25519_2interleave2(b,s1,s2); + + /* scalar multiplication */ + *r = pre[b[126]]; + for(i=125;i>=0;i--) + { + dbl_p1p1(&tp1p1, (ge25519_p2 *)r); + p1p1_to_p2((ge25519_p2 *) r, &tp1p1); + dbl_p1p1(&tp1p1, (ge25519_p2 *)r); + if(b[i]!=0) + { + p1p1_to_p3(r, &tp1p1); + add_p1p1(&tp1p1, r, &pre[b[i]]); + } + if(i != 0) p1p1_to_p2((ge25519_p2 *)r, &tp1p1); + else p1p1_to_p3(r, &tp1p1); + } +} + +#ifndef VERIFYONLY +void ge25519_scalarmult_base(ge25519_p3 *r, const sc25519 *s) +{ + signed char b[85]; + int i; + ge25519_aff t; + sc25519_window3(b,s); + + choose_t((ge25519_aff *)r, 0, b[0]); + fe25519_setone(&r->z); + fe25519_mul(&r->t, &r->x, &r->y); + for(i=1;i<85;i++) + { + choose_t(&t, (unsigned long long) i, b[i]); + ge25519_mixadd2(r, &t); + } +} +#endif diff --git a/usr.bin/signify/signify.c b/usr.bin/signify/signify.c index 65a51b951c4..3d668188532 100644 --- a/usr.bin/signify/signify.c +++ b/usr.bin/signify/signify.c @@ -1,4 +1,4 @@ -/* $OpenBSD: signify.c,v 1.13 2014/01/08 03:57:57 tedu Exp $ */ +/* $OpenBSD: signify.c,v 1.14 2014/01/08 05:00:01 tedu Exp $ */ /* * Copyright (c) 2013 Ted Unangst * @@ -159,6 +159,7 @@ readmsg(const char *filename, unsigned long long *msglenp) return msg; } +#ifndef VERIFYONLY static void writeall(int fd, const void *buf, size_t len, const char *filename) { @@ -302,6 +303,7 @@ sign(const char *seckeyfile, const char *inputfile, const char *sigfile) free(msg); } +#endif static void verifymsg(uint8_t *pubkey, uint8_t *msg, unsigned long long msglen, @@ -364,6 +366,7 @@ main(int argc, char **argv) while ((ch = getopt(argc, argv, "GSVno:p:s:")) != -1) { switch (ch) { +#ifndef VERIFYONLY case 'G': if (verb) usage(); @@ -374,6 +377,7 @@ main(int argc, char **argv) usage(); verb = SIGN; break; +#endif case 'V': if (verb) usage(); @@ -402,11 +406,14 @@ main(int argc, char **argv) if (verb == NONE) usage(); +#ifndef VERIFYONLY if (verb == GENERATE) { if (!pubkeyfile || !seckeyfile || argc != 0) usage(); generate(pubkeyfile, seckeyfile, rounds); - } else { + } else +#endif + { if (argc != 1) usage(); @@ -418,12 +425,14 @@ main(int argc, char **argv) errx(1, "path too long"); sigfile = sigfilebuf; } - +#ifndef VERIFYONLY if (verb == SIGN) { if (!seckeyfile) usage(); sign(seckeyfile, inputfile, sigfile); - } else if (verb == VERIFY) { + } else +#endif + if (verb == VERIFY) { if (!pubkeyfile) usage(); verify(pubkeyfile, inputfile, sigfile); -- 2.20.1