-#include "jpake.h"
-
+#include <openssl/jpake.h>
#include <openssl/crypto.h>
#include <openssl/sha.h>
#include <openssl/err.h>
#include <memory.h>
-#include <assert.h>
+#include <string.h>
/*
* In the definition, (xa, xb, xc, xd) are Alice's (x1, x2, x3, x4) or
* Bob's (x3, x4, x1, x2). If you see what I mean.
*/
-typedef struct
- {
- char *name; /* Must be unique */
+typedef struct {
+ 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} */
- } JPAKE_CTX_PUBLIC;
+ 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
- {
+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)
- {
+{
zkp->gr = BN_new();
zkp->b = BN_new();
- }
+}
static void JPAKE_ZKP_release(JPAKE_ZKP *zkp)
- {
+{
BN_free(zkp->b);
BN_free(zkp->gr);
- }
+}
/* 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
+#define JPAKE_STEP_PART_init JPAKE_STEP2_init
+#define JPAKE_STEP_PART_release JPAKE_STEP2_release
void JPAKE_STEP_PART_init(JPAKE_STEP_PART *p)
- {
+{
p->gx = BN_new();
JPAKE_ZKP_init(&p->zkpx);
- }
+}
void JPAKE_STEP_PART_release(JPAKE_STEP_PART *p)
- {
+{
JPAKE_ZKP_release(&p->zkpx);
BN_free(p->gx);
- }
+}
void JPAKE_STEP1_init(JPAKE_STEP1 *s1)
- {
+{
JPAKE_STEP_PART_init(&s1->p1);
JPAKE_STEP_PART_init(&s1->p2);
- }
+}
void JPAKE_STEP1_release(JPAKE_STEP1 *s1)
- {
+{
JPAKE_STEP_PART_release(&s1->p2);
JPAKE_STEP_PART_release(&s1->p1);
- }
+}
static void JPAKE_CTX_init(JPAKE_CTX *ctx, const char *name,
- const char *peer_name, const BIGNUM *p,
- const BIGNUM *g, const BIGNUM *q,
- const BIGNUM *secret)
- {
+ const char *peer_name, const BIGNUM *p,
+ const BIGNUM *g, const BIGNUM *q,
+ const BIGNUM *secret)
+{
ctx->p.name = OPENSSL_strdup(name);
ctx->p.peer_name = OPENSSL_strdup(peer_name);
ctx->p.p = BN_dup(p);
ctx->xb = BN_new();
ctx->key = BN_new();
ctx->ctx = BN_CTX_new();
- }
-
+}
+
static void JPAKE_CTX_release(JPAKE_CTX *ctx)
- {
+{
BN_CTX_free(ctx->ctx);
BN_clear_free(ctx->key);
BN_clear_free(ctx->xb);
OPENSSL_free(ctx->p.name);
memset(ctx, '\0', sizeof *ctx);
- }
-
+}
+
JPAKE_CTX *JPAKE_CTX_new(const char *name, const char *peer_name,
- const BIGNUM *p, const BIGNUM *g, const BIGNUM *q,
- const BIGNUM *secret)
- {
+ const BIGNUM *p, const BIGNUM *g, const BIGNUM *q,
+ const BIGNUM *secret)
+{
JPAKE_CTX *ctx = OPENSSL_malloc(sizeof *ctx);
+ if (ctx == NULL)
+ return NULL;
JPAKE_CTX_init(ctx, name, peer_name, p, g, q, secret);
return ctx;
- }
+}
void JPAKE_CTX_free(JPAKE_CTX *ctx)
- {
+{
+ if (!ctx)
+ return;
JPAKE_CTX_release(ctx);
OPENSSL_free(ctx);
- }
+}
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;
+ b[1] = l & 0xff;
SHA1_Update(sha, b, 2);
- }
+}
static void hashstring(SHA_CTX *sha, const char *string)
- {
+{
size_t l = strlen(string);
hashlength(sha, l);
SHA1_Update(sha, string, l);
- }
+}
-static void hashbn(SHA_CTX *sha, const BIGNUM *bn)
- {
+static int 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);
+
+ if (bin == NULL)
+ return 0;
hashlength(sha, l);
BN_bn2bin(bn, bin);
SHA1_Update(sha, bin, l);
- }
+ OPENSSL_free(bin);
+ return 1;
+}
/* 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)
- {
+static int 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));
- hashbn(&sha, p->zkpx.gr);
- hashbn(&sha, p->gx);
+ if (!hashbn(&sha, zkpg))
+ return 0;
+ OPENSSL_assert(!BN_is_zero(p->zkpx.gr));
+ if (!hashbn(&sha, p->zkpx.gr))
+ return 0;
+ if (!hashbn(&sha, p->gx))
+ return 0;
hashstring(&sha, proof_name);
SHA1_Final(md, &sha);
BN_bin2bn(md, SHA_DIGEST_LENGTH, h);
- }
+ return 1;
+}
/*
* 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)
- {
+static int generate_zkp(JPAKE_STEP_PART *p, const BIGNUM *x,
+ const BIGNUM *zkpg, JPAKE_CTX *ctx)
+{
+ int res = 0;
BIGNUM *r = BN_new();
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
*/
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... */
- zkp_hash(h, zkpg, p, ctx->p.name);
+ /* h=hash... */
+ if (!zkp_hash(h, zkpg, p, ctx->p.name))
+ goto end;
- /* 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 */
+ res = 1;
+ end:
+ /* cleanup */
BN_free(t);
BN_free(h);
BN_free(r);
- }
+ return res;
+}
static int verify_zkp(const JPAKE_STEP_PART *p, const BIGNUM *zkpg,
- JPAKE_CTX *ctx)
- {
+ JPAKE_CTX *ctx)
+{
BIGNUM *h = BN_new();
BIGNUM *t1 = BN_new();
BIGNUM *t2 = BN_new();
BIGNUM *t3 = BN_new();
int ret = 0;
- zkp_hash(h, zkpg, p, ctx->p.peer_name);
+ if (!zkp_hash(h, zkpg, p, ctx->p.peer_name))
+ goto end;
- /* 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 */
- if(BN_cmp(t3, p->zkpx.gr) == 0)
- ret = 1;
+ /* 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);
+ JPAKEerr(JPAKE_F_VERIFY_ZKP, JPAKE_R_ZKP_VERIFY_FAILED);
- /* cleanup */
+ end:
+ /* cleanup */
BN_free(t3);
BN_free(t2);
BN_free(t1);
BN_free(h);
return ret;
- }
+}
-static void generate_step_part(JPAKE_STEP_PART *p, const BIGNUM *x,
- const BIGNUM *g, JPAKE_CTX *ctx)
- {
+static int generate_step_part(JPAKE_STEP_PART *p, const BIGNUM *x,
+ const BIGNUM *g, JPAKE_CTX *ctx)
+{
BN_mod_exp(p->gx, g, x, ctx->p.p, ctx->ctx);
- generate_zkp(p, x, g, ctx);
- }
+ if (!generate_zkp(p, x, g, ctx))
+ return 0;
+ return 1;
+}
/* 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);
- }
+}
int JPAKE_STEP1_generate(JPAKE_STEP1 *send, JPAKE_CTX *ctx)
- {
+{
genrand(ctx);
- generate_step_part(&send->p1, ctx->xa, ctx->p.g, ctx);
- generate_step_part(&send->p2, ctx->xb, ctx->p.g, ctx);
+ if (!generate_step_part(&send->p1, ctx->xa, ctx->p.g, ctx))
+ return 0;
+ if (!generate_step_part(&send->p2, ctx->xb, ctx->p.g, ctx))
+ return 0;
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(!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) */
- 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 */
- 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 */
+{
+ 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) */
+ 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 */
+ 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 */
BN_copy(ctx->p.gxc, received->p1.gx);
BN_copy(ctx->p.gxd, received->p2.gx);
return 1;
- }
-
+}
int JPAKE_STEP2_generate(JPAKE_STEP2 *send, JPAKE_CTX *ctx)
- {
+{
+ int ret;
+
BIGNUM *t1 = BN_new();
BIGNUM *t2 = BN_new();
- /*
+ /*-
* 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
*
* 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);
+ ret = generate_step_part(send, t2, t1, ctx);
- /* cleanup */
+ /* cleanup */
BN_free(t1);
BN_free(t2);
- return 1;
- }
+ return ret;
+}
/* 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}
* [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);
return 1;
- }
+}
int JPAKE_STEP2_process(JPAKE_CTX *ctx, const JPAKE_STEP2 *received)
- {
+{
BIGNUM *t1 = BN_new();
BIGNUM *t2 = BN_new();
int ret = 0;
- /*
+ /*-
* 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))
- ret = 1;
+ if (verify_zkp(received, t1, ctx))
+ ret = 1;
else
- JPAKEerr(JPAKE_F_JPAKE_STEP2_PROCESS, JPAKE_R_VERIFY_B_FAILED);
+ JPAKEerr(JPAKE_F_JPAKE_STEP2_PROCESS, JPAKE_R_VERIFY_B_FAILED);
compute_key(ctx, received->gx);
- /* cleanup */
+ /* cleanup */
BN_free(t2);
BN_free(t1);
return ret;
- }
+}
-static void quickhashbn(unsigned char *md, const BIGNUM *bn)
- {
+static int quickhashbn(unsigned char *md, const BIGNUM *bn)
+{
SHA_CTX sha;
SHA1_Init(&sha);
- hashbn(&sha, bn);
+ if (!hashbn(&sha, bn))
+ return 0;
SHA1_Final(md, &sha);
- }
+ return 1;
+}
void JPAKE_STEP3A_init(JPAKE_STEP3A *s3a)
- {}
+{
+}
int JPAKE_STEP3A_generate(JPAKE_STEP3A *send, JPAKE_CTX *ctx)
- {
- quickhashbn(send->hhk, ctx->key);
+{
+ if (!quickhashbn(send->hhk, ctx->key))
+ return 0;
SHA1(send->hhk, sizeof send->hhk, send->hhk);
return 1;
- }
+}
int JPAKE_STEP3A_process(JPAKE_CTX *ctx, const JPAKE_STEP3A *received)
- {
+{
unsigned char hhk[SHA_DIGEST_LENGTH];
- quickhashbn(hhk, ctx->key);
+ if (!quickhashbn(hhk, ctx->key))
+ return 0;
SHA1(hhk, sizeof hhk, hhk);
- if(memcmp(hhk, received->hhk, sizeof hhk))
- {
- JPAKEerr(JPAKE_F_JPAKE_STEP3A_PROCESS, JPAKE_R_HASH_OF_HASH_OF_KEY_MISMATCH);
- return 0;
- }
- return 1;
+ if (memcmp(hhk, received->hhk, sizeof hhk)) {
+ JPAKEerr(JPAKE_F_JPAKE_STEP3A_PROCESS,
+ JPAKE_R_HASH_OF_HASH_OF_KEY_MISMATCH);
+ return 0;
}
+ return 1;
+}
void JPAKE_STEP3A_release(JPAKE_STEP3A *s3a)
- {}
+{
+}
void JPAKE_STEP3B_init(JPAKE_STEP3B *s3b)
- {}
+{
+}
int JPAKE_STEP3B_generate(JPAKE_STEP3B *send, JPAKE_CTX *ctx)
- {
- quickhashbn(send->hk, ctx->key);
-
+{
+ if (!quickhashbn(send->hk, ctx->key))
+ return 0;
return 1;
- }
+}
int JPAKE_STEP3B_process(JPAKE_CTX *ctx, const JPAKE_STEP3B *received)
- {
+{
unsigned char hk[SHA_DIGEST_LENGTH];
- quickhashbn(hk, ctx->key);
- if(memcmp(hk, received->hk, sizeof hk))
- {
- JPAKEerr(JPAKE_F_JPAKE_STEP3B_PROCESS, JPAKE_R_HASH_OF_KEY_MISMATCH);
- return 0;
- }
- return 1;
+ if (!quickhashbn(hk, ctx->key))
+ return 0;
+ if (memcmp(hk, received->hk, sizeof hk)) {
+ JPAKEerr(JPAKE_F_JPAKE_STEP3B_PROCESS, JPAKE_R_HASH_OF_KEY_MISMATCH);
+ return 0;
}
+ return 1;
+}
void JPAKE_STEP3B_release(JPAKE_STEP3B *s3b)
- {}
+{
+}
const BIGNUM *JPAKE_get_shared_key(JPAKE_CTX *ctx)
- {
+{
return ctx->key;
- }
-
+}
projects / openssl.git / blobdiff