X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=crypto%2Fjpake%2Fjpake.c;h=8e4b633ccc5310f85f2f242f73560e51f0c44260;hb=057c8a2b9e24b91d4e98b38bf1c91f232f065637;hp=3ed1d1b15823e9ac375473bf27ea4a9ceed7332d;hpb=6caa4edd3e6410aff7c80011d905abcd3c1b1143;p=oweals%2Fopenssl.git diff --git a/crypto/jpake/jpake.c b/crypto/jpake/jpake.c index 3ed1d1b158..8e4b633ccc 100644 --- a/crypto/jpake/jpake.c +++ b/crypto/jpake/jpake.c @@ -4,7 +4,6 @@ #include #include #include -#include /* * In the definition, (xa, xb, xc, xd) are Alice's (x1, x2, x3, x4) or @@ -13,23 +12,23 @@ typedef struct { - char *name; // Must be unique + char *name; /* Must be unique */ char *peer_name; BIGNUM *p; BIGNUM *g; BIGNUM *q; - BIGNUM *gxc; // Alice's g^{x3} or Bob's g^{x1} - BIGNUM *gxd; // Alice's g^{x4} or Bob's g^{x2} + BIGNUM *gxc; /* Alice's g^{x3} or Bob's g^{x1} */ + BIGNUM *gxd; /* Alice's g^{x4} or Bob's g^{x2} */ } JPAKE_CTX_PUBLIC; struct JPAKE_CTX { JPAKE_CTX_PUBLIC p; - BIGNUM *secret; // The shared secret + BIGNUM *secret; /* The shared secret */ BN_CTX *ctx; - BIGNUM *xa; // Alice's x1 or Bob's x3 - BIGNUM *xb; // Alice's x2 or Bob's x4 - BIGNUM *key; // The calculated (shared) key + BIGNUM *xa; /* Alice's x1 or Bob's x3 */ + BIGNUM *xb; /* Alice's x2 or Bob's x4 */ + BIGNUM *key; /* The calculated (shared) key */ }; static void JPAKE_ZKP_init(JPAKE_ZKP *zkp) @@ -44,7 +43,7 @@ static void JPAKE_ZKP_release(JPAKE_ZKP *zkp) BN_free(zkp->gr); } -// Two birds with one stone - make the global name as expected +/* Two birds with one stone - make the global name as expected */ #define JPAKE_STEP_PART_init JPAKE_STEP2_init #define JPAKE_STEP_PART_release JPAKE_STEP2_release @@ -134,7 +133,7 @@ static void hashlength(SHA_CTX *sha, size_t l) { unsigned char b[2]; - assert(l <= 0xffff); + OPENSSL_assert(l <= 0xffff); b[0] = l >> 8; b[1] = l&0xff; SHA1_Update(sha, b, 2); @@ -151,25 +150,28 @@ static void hashstring(SHA_CTX *sha, const char *string) static void hashbn(SHA_CTX *sha, const BIGNUM *bn) { size_t l = BN_num_bytes(bn); - unsigned char *bin = alloca(l); + unsigned char *bin = OPENSSL_malloc(l); hashlength(sha, l); BN_bn2bin(bn, bin); SHA1_Update(sha, bin, l); + OPENSSL_free(bin); } -// h=hash(g, g^r, g^x, name) +/* h=hash(g, g^r, g^x, name) */ static void zkp_hash(BIGNUM *h, const BIGNUM *zkpg, const JPAKE_STEP_PART *p, const char *proof_name) { unsigned char md[SHA_DIGEST_LENGTH]; SHA_CTX sha; - // XXX: hash should not allow moving of the boundaries - Java code - // is flawed in this respect. Length encoding seems simplest. + /* + * XXX: hash should not allow moving of the boundaries - Java code + * is flawed in this respect. Length encoding seems simplest. + */ SHA1_Init(&sha); hashbn(&sha, zkpg); - assert(!BN_is_zero(p->zkpx.gr)); + OPENSSL_assert(!BN_is_zero(p->zkpx.gr)); hashbn(&sha, p->zkpx.gr); hashbn(&sha, p->gx); hashstring(&sha, proof_name); @@ -177,8 +179,10 @@ static void zkp_hash(BIGNUM *h, const BIGNUM *zkpg, const JPAKE_STEP_PART *p, BN_bin2bn(md, SHA_DIGEST_LENGTH, h); } -// Prove knowledge of x -// Note that p->gx has already been calculated +/* + * Prove knowledge of x + * Note that p->gx has already been calculated + */ static void generate_zkp(JPAKE_STEP_PART *p, const BIGNUM *x, const BIGNUM *zkpg, JPAKE_CTX *ctx) { @@ -186,20 +190,22 @@ static void generate_zkp(JPAKE_STEP_PART *p, const BIGNUM *x, BIGNUM *h = BN_new(); BIGNUM *t = BN_new(); - // r in [0,q) - // XXX: Java chooses r in [0, 2^160) - i.e. distribution not uniform + /* + * r in [0,q) + * XXX: Java chooses r in [0, 2^160) - i.e. distribution not uniform + */ BN_rand_range(r, ctx->p.q); - // g^r + /* g^r */ BN_mod_exp(p->zkpx.gr, zkpg, r, ctx->p.p, ctx->ctx); - // h=hash... + /* h=hash... */ zkp_hash(h, zkpg, p, ctx->p.name); - // b = r - x*h + /* b = r - x*h */ BN_mod_mul(t, x, h, ctx->p.q, ctx->ctx); BN_mod_sub(p->zkpx.b, r, t, ctx->p.q, ctx->ctx); - // cleanup + /* cleanup */ BN_free(t); BN_free(h); BN_free(r); @@ -216,20 +222,20 @@ static int verify_zkp(const JPAKE_STEP_PART *p, const BIGNUM *zkpg, zkp_hash(h, zkpg, p, ctx->p.peer_name); - // t1 = g^b + /* t1 = g^b */ BN_mod_exp(t1, zkpg, p->zkpx.b, ctx->p.p, ctx->ctx); - // t2 = (g^x)^h = g^{hx} + /* t2 = (g^x)^h = g^{hx} */ BN_mod_exp(t2, p->gx, h, ctx->p.p, ctx->ctx); - // t3 = t1 * t2 = g^{hx} * g^b = g^{hx+b} = g^r (allegedly) + /* t3 = t1 * t2 = g^{hx} * g^b = g^{hx+b} = g^r (allegedly) */ BN_mod_mul(t3, t1, t2, ctx->p.p, ctx->ctx); - // verify t3 == g^r + /* verify t3 == g^r */ if(BN_cmp(t3, p->zkpx.gr) == 0) ret = 1; else JPAKEerr(JPAKE_F_VERIFY_ZKP, JPAKE_R_ZKP_VERIFY_FAILED); - // cleanup + /* cleanup */ BN_free(t3); BN_free(t2); BN_free(t1); @@ -245,25 +251,25 @@ static void generate_step_part(JPAKE_STEP_PART *p, const BIGNUM *x, generate_zkp(p, x, g, ctx); } -// Generate each party's random numbers. xa is in [0, q), xb is in [1, q). +/* Generate each party's random numbers. xa is in [0, q), xb is in [1, q). */ static void genrand(JPAKE_CTX *ctx) { BIGNUM *qm1; - // xa in [0, q) + /* xa in [0, q) */ BN_rand_range(ctx->xa, ctx->p.q); - // q-1 + /* q-1 */ qm1 = BN_new(); BN_copy(qm1, ctx->p.q); BN_sub_word(qm1, 1); - // ... and xb in [0, q-1) + /* ... and xb in [0, q-1) */ BN_rand_range(ctx->xb, qm1); - // [1, q) + /* [1, q) */ BN_add_word(ctx->xb, 1); - // cleanup + /* cleanup */ BN_free(qm1); } @@ -276,30 +282,59 @@ int JPAKE_STEP1_generate(JPAKE_STEP1 *send, JPAKE_CTX *ctx) return 1; } +/* g^x is a legal value */ +static int is_legal(const BIGNUM *gx, const JPAKE_CTX *ctx) + { + BIGNUM *t; + int res; + + if(BN_is_negative(gx) || BN_is_zero(gx) || BN_cmp(gx, ctx->p.p) >= 0) + return 0; + + t = BN_new(); + BN_mod_exp(t, gx, ctx->p.q, ctx->p.p, ctx->ctx); + res = BN_is_one(t); + BN_free(t); + + return res; + } + int JPAKE_STEP1_process(JPAKE_CTX *ctx, const JPAKE_STEP1 *received) { - // verify their ZKP(xc) + if(!is_legal(received->p1.gx, ctx)) + { + JPAKEerr(JPAKE_F_JPAKE_STEP1_PROCESS, JPAKE_R_G_TO_THE_X3_IS_NOT_LEGAL); + return 0; + } + + if(!is_legal(received->p2.gx, ctx)) + { + JPAKEerr(JPAKE_F_JPAKE_STEP1_PROCESS, JPAKE_R_G_TO_THE_X4_IS_NOT_LEGAL); + return 0; + } + + /* verify their ZKP(xc) */ if(!verify_zkp(&received->p1, ctx->p.g, ctx)) { JPAKEerr(JPAKE_F_JPAKE_STEP1_PROCESS, JPAKE_R_VERIFY_X3_FAILED); return 0; } - // verify their ZKP(xd) + /* verify their ZKP(xd) */ if(!verify_zkp(&received->p2, ctx->p.g, ctx)) { JPAKEerr(JPAKE_F_JPAKE_STEP1_PROCESS, JPAKE_R_VERIFY_X4_FAILED); return 0; } - // g^xd != 1 + /* g^xd != 1 */ if(BN_is_one(received->p2.gx)) { JPAKEerr(JPAKE_F_JPAKE_STEP1_PROCESS, JPAKE_R_G_TO_THE_X4_IS_ONE); return 0; } - // Save the bits we need for later + /* Save the bits we need for later */ BN_copy(ctx->p.gxc, received->p1.gx); BN_copy(ctx->p.gxd, received->p2.gx); @@ -312,57 +347,63 @@ int JPAKE_STEP2_generate(JPAKE_STEP2 *send, JPAKE_CTX *ctx) BIGNUM *t1 = BN_new(); BIGNUM *t2 = BN_new(); - // X = g^{(xa + xc + xd) * xb * s} - // t1 = g^xa + /* + * X = g^{(xa + xc + xd) * xb * s} + * t1 = g^xa + */ BN_mod_exp(t1, ctx->p.g, ctx->xa, ctx->p.p, ctx->ctx); - // t2 = t1 * g^{xc} = g^{xa} * g^{xc} = g^{xa + xc} + /* t2 = t1 * g^{xc} = g^{xa} * g^{xc} = g^{xa + xc} */ BN_mod_mul(t2, t1, ctx->p.gxc, ctx->p.p, ctx->ctx); - // t1 = t2 * g^{xd} = g^{xa + xc + xd} + /* t1 = t2 * g^{xd} = g^{xa + xc + xd} */ BN_mod_mul(t1, t2, ctx->p.gxd, ctx->p.p, ctx->ctx); - // t2 = xb * s + /* t2 = xb * s */ BN_mod_mul(t2, ctx->xb, ctx->secret, ctx->p.q, ctx->ctx); - // ZKP(xb * s) - // XXX: this is kinda funky, because we're using - // - // g' = g^{xa + xc + xd} - // - // as the generator, which means X is g'^{xb * s} - // X = t1^{t2} = t1^{xb * s} = g^{(xa + xc + xd) * xb * s} + /* + * ZKP(xb * s) + * XXX: this is kinda funky, because we're using + * + * g' = g^{xa + xc + xd} + * + * as the generator, which means X is g'^{xb * s} + * X = t1^{t2} = t1^{xb * s} = g^{(xa + xc + xd) * xb * s} + */ generate_step_part(send, t2, t1, ctx); - // cleanup + /* cleanup */ BN_free(t1); BN_free(t2); return 1; } -// gx = g^{xc + xa + xb} * xd * s +/* gx = g^{xc + xa + xb} * xd * s */ static int compute_key(JPAKE_CTX *ctx, const BIGNUM *gx) { BIGNUM *t1 = BN_new(); BIGNUM *t2 = BN_new(); BIGNUM *t3 = BN_new(); - // K = (gx/g^{xb * xd * s})^{xb} - // = (g^{(xc + xa + xb) * xd * s - xb * xd *s})^{xb} - // = (g^{(xa + xc) * xd * s})^{xb} - // = g^{(xa + xc) * xb * xd * s} - // [which is the same regardless of who calculates it] + /* + * K = (gx/g^{xb * xd * s})^{xb} + * = (g^{(xc + xa + xb) * xd * s - xb * xd *s})^{xb} + * = (g^{(xa + xc) * xd * s})^{xb} + * = g^{(xa + xc) * xb * xd * s} + * [which is the same regardless of who calculates it] + */ - // t1 = (g^{xd})^{xb} = g^{xb * xd} + /* t1 = (g^{xd})^{xb} = g^{xb * xd} */ BN_mod_exp(t1, ctx->p.gxd, ctx->xb, ctx->p.p, ctx->ctx); - // t2 = -s = q-s + /* t2 = -s = q-s */ BN_sub(t2, ctx->p.q, ctx->secret); - // t3 = t1^t2 = g^{-xb * xd * s} + /* t3 = t1^t2 = g^{-xb * xd * s} */ BN_mod_exp(t3, t1, t2, ctx->p.p, ctx->ctx); - // t1 = gx * t3 = X/g^{xb * xd * s} + /* t1 = gx * t3 = X/g^{xb * xd * s} */ BN_mod_mul(t1, gx, t3, ctx->p.p, ctx->ctx); - // K = t1^{xb} + /* K = t1^{xb} */ BN_mod_exp(ctx->key, t1, ctx->xb, ctx->p.p, ctx->ctx); - // cleanup + /* cleanup */ BN_free(t3); BN_free(t2); BN_free(t1); @@ -376,12 +417,14 @@ int JPAKE_STEP2_process(JPAKE_CTX *ctx, const JPAKE_STEP2 *received) BIGNUM *t2 = BN_new(); int ret = 0; - // g' = g^{xc + xa + xb} [from our POV] - // t1 = xa + xb + /* + * g' = g^{xc + xa + xb} [from our POV] + * t1 = xa + xb + */ BN_mod_add(t1, ctx->xa, ctx->xb, ctx->p.q, ctx->ctx); - // t2 = g^{t1} = g^{xa+xb} + /* t2 = g^{t1} = g^{xa+xb} */ BN_mod_exp(t2, ctx->p.g, t1, ctx->p.p, ctx->ctx); - // t1 = g^{xc} * t2 = g^{xc + xa + xb} + /* t1 = g^{xc} * t2 = g^{xc + xa + xb} */ BN_mod_mul(t1, ctx->p.gxc, t2, ctx->p.p, ctx->ctx); if(verify_zkp(received, t1, ctx)) @@ -391,7 +434,7 @@ int JPAKE_STEP2_process(JPAKE_CTX *ctx, const JPAKE_STEP2 *received) compute_key(ctx, received->gx); - // cleanup + /* cleanup */ BN_free(t2); BN_free(t1);