Mercurial > dropbear
view ecdsa.c @ 1306:34e6127ef02e
merge fixes from PuTTY import.c
toint() from misc.c
(revids are from hggit conversion)
changeset: 4620:60a336a6c85c
user: Simon Tatham <[email protected]>
date: Thu Feb 25 20:26:33 2016 +0000
files: import.c
description:
Fix potential segfaults in reading OpenSSH's ASN.1 key format.
The length coming back from ber_read_id_len might have overflowed, so
treat it as potentially negative. Also, while I'm here, accumulate it
inside ber_read_id_len as an unsigned, so as to avoid undefined
behaviour on integer overflow, and toint() it before return.
Thanks to Hanno Böck for spotting this, with the aid of AFL.
(cherry picked from commit 5b7833cd474a24ec098654dcba8cb9509f3bf2c1)
Conflicts:
import.c
(cherry-picker's note: resolving the conflict involved removing an
entire section of the original commit which fixed ECDSA code not
present on this branch)
changeset: 4619:9c6c638d98d8
user: Simon Tatham <[email protected]>
date: Sun Jul 14 10:45:54 2013 +0000
files: import.c ssh.c sshdss.c sshpubk.c sshrsa.c
description:
Tighten up a lot of casts from unsigned to int which are read by one
of the GET_32BIT macros and then used as length fields. Missing bounds
checks against zero have been added, and also I've introduced a helper
function toint() which casts from unsigned to int in such a way as to
avoid C undefined behaviour, since I'm not sure I trust compilers any
more to do the obviously sensible thing.
[originally from svn r9918]
changeset: 4618:3957829f24d3
user: Simon Tatham <[email protected]>
date: Mon Jul 08 22:36:04 2013 +0000
files: import.c sshdss.c sshrsa.c
description:
Add an assortment of extra safety checks.
[originally from svn r9896]
changeset: 4617:2cddee0bce12
user: Jacob Nevins <[email protected]>
date: Wed Dec 07 00:24:45 2005 +0000
files: import.c
description:
Institutional failure to memset() things pointed at rather than pointers.
Things should now be zeroed and memory not leaked. Spotted by Brant Thomsen.
[originally from svn r6476]
changeset: 4616:24ac78a9c71d
user: Simon Tatham <[email protected]>
date: Wed Feb 11 13:58:27 2004 +0000
files: import.c
description:
Jacob's last-minute testing found a couple of trivial bugs in
import.c, and my attempts to reproduce them in cmdgen found another
one there :-)
[originally from svn r3847]
changeset: 4615:088d39a73db0
user: Simon Tatham <[email protected]>
date: Thu Jan 22 18:52:49 2004 +0000
files: import.c
description:
Placate some gcc warnings.
[originally from svn r3761]
changeset: 4614:e4288bad4d93
parent: 1758:108b8924593d
user: Simon Tatham <[email protected]>
date: Fri Oct 03 21:21:23 2003 +0000
files: import.c
description:
My ASN.1 decoder returned wrong IDs for anything above 0x1E! Good
job it's never had to yet. Ahem.
[originally from svn r3479]
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Tue, 12 Jul 2016 23:00:01 +0800 |
parents | 2bb4c662d1c2 |
children | 750ec4ec4cbe |
line wrap: on
line source
#include "options.h" #include "includes.h" #include "dbutil.h" #include "crypto_desc.h" #include "ecc.h" #include "ecdsa.h" #include "signkey.h" #ifdef DROPBEAR_ECDSA int signkey_is_ecdsa(enum signkey_type type) { return type == DROPBEAR_SIGNKEY_ECDSA_NISTP256 || type == DROPBEAR_SIGNKEY_ECDSA_NISTP384 || type == DROPBEAR_SIGNKEY_ECDSA_NISTP521; } enum signkey_type ecdsa_signkey_type(ecc_key * key) { #ifdef DROPBEAR_ECC_256 if (key->dp == ecc_curve_nistp256.dp) { return DROPBEAR_SIGNKEY_ECDSA_NISTP256; } #endif #ifdef DROPBEAR_ECC_384 if (key->dp == ecc_curve_nistp384.dp) { return DROPBEAR_SIGNKEY_ECDSA_NISTP384; } #endif #ifdef DROPBEAR_ECC_521 if (key->dp == ecc_curve_nistp521.dp) { return DROPBEAR_SIGNKEY_ECDSA_NISTP521; } #endif return DROPBEAR_SIGNKEY_NONE; } ecc_key *gen_ecdsa_priv_key(unsigned int bit_size) { const ltc_ecc_set_type *dp = NULL; /* curve domain parameters */ ecc_key *new_key = NULL; switch (bit_size) { #ifdef DROPBEAR_ECC_256 case 256: dp = ecc_curve_nistp256.dp; break; #endif #ifdef DROPBEAR_ECC_384 case 384: dp = ecc_curve_nistp384.dp; break; #endif #ifdef DROPBEAR_ECC_521 case 521: dp = ecc_curve_nistp521.dp; break; #endif } if (!dp) { dropbear_exit("Key size %d isn't valid. Try " #ifdef DROPBEAR_ECC_256 "256 " #endif #ifdef DROPBEAR_ECC_384 "384 " #endif #ifdef DROPBEAR_ECC_521 "521 " #endif , bit_size); } new_key = m_malloc(sizeof(*new_key)); if (ecc_make_key_ex(NULL, dropbear_ltc_prng, new_key, dp) != CRYPT_OK) { dropbear_exit("ECC error"); } return new_key; } ecc_key *buf_get_ecdsa_pub_key(buffer* buf) { unsigned char *key_ident = NULL, *identifier = NULL; unsigned int key_ident_len, identifier_len; buffer *q_buf = NULL; struct dropbear_ecc_curve **curve; ecc_key *new_key = NULL; /* string "ecdsa-sha2-[identifier]" */ key_ident = (unsigned char*)buf_getstring(buf, &key_ident_len); /* string "[identifier]" */ identifier = (unsigned char*)buf_getstring(buf, &identifier_len); if (key_ident_len != identifier_len + strlen("ecdsa-sha2-")) { TRACE(("Bad identifier lengths")) goto out; } if (memcmp(&key_ident[strlen("ecdsa-sha2-")], identifier, identifier_len) != 0) { TRACE(("mismatching identifiers")) goto out; } for (curve = dropbear_ecc_curves; *curve; curve++) { if (memcmp(identifier, (char*)(*curve)->name, strlen((char*)(*curve)->name)) == 0) { break; } } if (!*curve) { TRACE(("couldn't match ecc curve")) goto out; } /* string Q */ q_buf = buf_getstringbuf(buf); new_key = buf_get_ecc_raw_pubkey(q_buf, *curve); out: m_free(key_ident); m_free(identifier); if (q_buf) { buf_free(q_buf); q_buf = NULL; } TRACE(("leave buf_get_ecdsa_pub_key")) return new_key; } ecc_key *buf_get_ecdsa_priv_key(buffer *buf) { ecc_key *new_key = NULL; TRACE(("enter buf_get_ecdsa_priv_key")) new_key = buf_get_ecdsa_pub_key(buf); if (!new_key) { return NULL; } if (buf_getmpint(buf, new_key->k) != DROPBEAR_SUCCESS) { ecc_free(new_key); m_free(new_key); return NULL; } return new_key; } void buf_put_ecdsa_pub_key(buffer *buf, ecc_key *key) { struct dropbear_ecc_curve *curve = NULL; char key_ident[30]; curve = curve_for_dp(key->dp); snprintf(key_ident, sizeof(key_ident), "ecdsa-sha2-%s", curve->name); buf_putstring(buf, key_ident, strlen(key_ident)); buf_putstring(buf, curve->name, strlen(curve->name)); buf_put_ecc_raw_pubkey_string(buf, key); } void buf_put_ecdsa_priv_key(buffer *buf, ecc_key *key) { buf_put_ecdsa_pub_key(buf, key); buf_putmpint(buf, key->k); } void buf_put_ecdsa_sign(buffer *buf, ecc_key *key, buffer *data_buf) { /* Based on libtomcrypt's ecc_sign_hash but without the asn1 */ int err = DROPBEAR_FAILURE; struct dropbear_ecc_curve *curve = NULL; hash_state hs; unsigned char hash[64]; void *e = NULL, *p = NULL, *s = NULL, *r; char key_ident[30]; buffer *sigbuf = NULL; TRACE(("buf_put_ecdsa_sign")) curve = curve_for_dp(key->dp); if (ltc_init_multi(&r, &s, &p, &e, NULL) != CRYPT_OK) { goto out; } curve->hash_desc->init(&hs); curve->hash_desc->process(&hs, data_buf->data, data_buf->len); curve->hash_desc->done(&hs, hash); if (ltc_mp.unsigned_read(e, hash, curve->hash_desc->hashsize) != CRYPT_OK) { goto out; } if (ltc_mp.read_radix(p, (char *)key->dp->order, 16) != CRYPT_OK) { goto out; } for (;;) { ecc_key R_key; /* ephemeral key */ if (ecc_make_key_ex(NULL, dropbear_ltc_prng, &R_key, key->dp) != CRYPT_OK) { goto out; } if (ltc_mp.mpdiv(R_key.pubkey.x, p, NULL, r) != CRYPT_OK) { goto out; } if (ltc_mp.compare_d(r, 0) == LTC_MP_EQ) { /* try again */ ecc_free(&R_key); continue; } /* k = 1/k */ if (ltc_mp.invmod(R_key.k, p, R_key.k) != CRYPT_OK) { goto out; } /* s = xr */ if (ltc_mp.mulmod(key->k, r, p, s) != CRYPT_OK) { goto out; } /* s = e + xr */ if (ltc_mp.add(e, s, s) != CRYPT_OK) { goto out; } if (ltc_mp.mpdiv(s, p, NULL, s) != CRYPT_OK) { goto out; } /* s = (e + xr)/k */ if (ltc_mp.mulmod(s, R_key.k, p, s) != CRYPT_OK) { goto out; } ecc_free(&R_key); if (ltc_mp.compare_d(s, 0) != LTC_MP_EQ) { break; } } snprintf(key_ident, sizeof(key_ident), "ecdsa-sha2-%s", curve->name); buf_putstring(buf, key_ident, strlen(key_ident)); /* enough for nistp521 */ sigbuf = buf_new(200); buf_putmpint(sigbuf, (mp_int*)r); buf_putmpint(sigbuf, (mp_int*)s); buf_putbufstring(buf, sigbuf); err = DROPBEAR_SUCCESS; out: if (r && s && p && e) { ltc_deinit_multi(r, s, p, e, NULL); } if (sigbuf) { buf_free(sigbuf); } if (err == DROPBEAR_FAILURE) { dropbear_exit("ECC error"); } } /* returns values in s and r returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE */ static int buf_get_ecdsa_verify_params(buffer *buf, void *r, void* s) { int ret = DROPBEAR_FAILURE; unsigned int sig_len; unsigned int sig_pos; sig_len = buf_getint(buf); sig_pos = buf->pos; if (buf_getmpint(buf, r) != DROPBEAR_SUCCESS) { goto out; } if (buf_getmpint(buf, s) != DROPBEAR_SUCCESS) { goto out; } if (buf->pos - sig_pos != sig_len) { goto out; } ret = DROPBEAR_SUCCESS; out: return ret; } int buf_ecdsa_verify(buffer *buf, ecc_key *key, buffer *data_buf) { /* Based on libtomcrypt's ecc_verify_hash but without the asn1 */ int ret = DROPBEAR_FAILURE; hash_state hs; struct dropbear_ecc_curve *curve = NULL; unsigned char hash[64]; ecc_point *mG = NULL, *mQ = NULL; void *r = NULL, *s = NULL, *v = NULL, *w = NULL, *u1 = NULL, *u2 = NULL, *e = NULL, *p = NULL, *m = NULL; void *mp = NULL; /* verify * * w = s^-1 mod n * u1 = xw * u2 = rw * X = u1*G + u2*Q * v = X_x1 mod n * accept if v == r */ TRACE(("buf_ecdsa_verify")) curve = curve_for_dp(key->dp); mG = ltc_ecc_new_point(); mQ = ltc_ecc_new_point(); if (ltc_init_multi(&r, &s, &v, &w, &u1, &u2, &p, &e, &m, NULL) != CRYPT_OK || !mG || !mQ) { dropbear_exit("ECC error"); } if (buf_get_ecdsa_verify_params(buf, r, s) != DROPBEAR_SUCCESS) { goto out; } curve->hash_desc->init(&hs); curve->hash_desc->process(&hs, data_buf->data, data_buf->len); curve->hash_desc->done(&hs, hash); if (ltc_mp.unsigned_read(e, hash, curve->hash_desc->hashsize) != CRYPT_OK) { goto out; } /* get the order */ if (ltc_mp.read_radix(p, (char *)key->dp->order, 16) != CRYPT_OK) { goto out; } /* get the modulus */ if (ltc_mp.read_radix(m, (char *)key->dp->prime, 16) != CRYPT_OK) { goto out; } /* check for zero */ if (ltc_mp.compare_d(r, 0) == LTC_MP_EQ || ltc_mp.compare_d(s, 0) == LTC_MP_EQ || ltc_mp.compare(r, p) != LTC_MP_LT || ltc_mp.compare(s, p) != LTC_MP_LT) { goto out; } /* w = s^-1 mod n */ if (ltc_mp.invmod(s, p, w) != CRYPT_OK) { goto out; } /* u1 = ew */ if (ltc_mp.mulmod(e, w, p, u1) != CRYPT_OK) { goto out; } /* u2 = rw */ if (ltc_mp.mulmod(r, w, p, u2) != CRYPT_OK) { goto out; } /* find mG and mQ */ if (ltc_mp.read_radix(mG->x, (char *)key->dp->Gx, 16) != CRYPT_OK) { goto out; } if (ltc_mp.read_radix(mG->y, (char *)key->dp->Gy, 16) != CRYPT_OK) { goto out; } if (ltc_mp.set_int(mG->z, 1) != CRYPT_OK) { goto out; } if (ltc_mp.copy(key->pubkey.x, mQ->x) != CRYPT_OK || ltc_mp.copy(key->pubkey.y, mQ->y) != CRYPT_OK || ltc_mp.copy(key->pubkey.z, mQ->z) != CRYPT_OK) { goto out; } /* compute u1*mG + u2*mQ = mG */ if (ltc_mp.ecc_mul2add == NULL) { if (ltc_mp.ecc_ptmul(u1, mG, mG, m, 0) != CRYPT_OK) { goto out; } if (ltc_mp.ecc_ptmul(u2, mQ, mQ, m, 0) != CRYPT_OK) { goto out; } /* find the montgomery mp */ if (ltc_mp.montgomery_setup(m, &mp) != CRYPT_OK) { goto out; } /* add them */ if (ltc_mp.ecc_ptadd(mQ, mG, mG, m, mp) != CRYPT_OK) { goto out; } /* reduce */ if (ltc_mp.ecc_map(mG, m, mp) != CRYPT_OK) { goto out; } } else { /* use Shamir's trick to compute u1*mG + u2*mQ using half of the doubles */ if (ltc_mp.ecc_mul2add(mG, u1, mQ, u2, mG, m) != CRYPT_OK) { goto out; } } /* v = X_x1 mod n */ if (ltc_mp.mpdiv(mG->x, p, NULL, v) != CRYPT_OK) { goto out; } /* does v == r */ if (ltc_mp.compare(v, r) == LTC_MP_EQ) { ret = DROPBEAR_SUCCESS; } out: ltc_ecc_del_point(mG); ltc_ecc_del_point(mQ); ltc_deinit_multi(r, s, v, w, u1, u2, p, e, m, NULL); if (mp != NULL) { ltc_mp.montgomery_deinit(mp); } return ret; } #endif /* DROPBEAR_ECDSA */