diff options
| -rw-r--r-- | crypto_desc.c | 2 | ||||
| -rw-r--r-- | debug.h | 4 | ||||
| -rw-r--r-- | ecc.c | 46 | ||||
| -rw-r--r-- | ecc.h | 10 | ||||
| -rw-r--r-- | ecdsa.c | 55 |
5 files changed, 100 insertions, 17 deletions
diff --git a/crypto_desc.c b/crypto_desc.c index 403e085..ed4de30 100644 --- a/crypto_desc.c +++ b/crypto_desc.c @@ -2,6 +2,7 @@ #include "dbutil.h" #include "crypto_desc.h" #include "ltc_prng.h" +#include "ecc.h" #ifdef DROPBEAR_LTC_PRNG int dropbear_ltc_prng = -1; @@ -68,6 +69,7 @@ void crypto_init() { #ifdef DROPBEAR_ECC ltc_mp = ltm_desc; + dropbear_ecc_fill_dp(); #endif } @@ -39,7 +39,7 @@ * Caution: Don't use this in an unfriendly environment (ie unfirewalled), * since the printing may not sanitise strings etc. This will add a reasonable * amount to your executable size. */ -#define DEBUG_TRACE +/*#define DEBUG_TRACE*/ /* All functions writing to the cleartext payload buffer call * CHECKCLEARTOWRITE() before writing. This is only really useful if you're @@ -69,7 +69,7 @@ /* To debug with GDB it is easier to run with no forking of child processes. You will need to pass "-F" as well. */ -#define DEBUG_NOFORK +/*#define DEBUG_NOFORK*/ /* For testing as non-root on shadowed systems, include the crypt of a password @@ -6,30 +6,60 @@ #ifdef DROPBEAR_ECC -// TODO: use raw bytes for the dp rather than the hex strings in libtomcrypt's ecc.c +// .dp members are filled out by dropbear_ecc_fill_dp() at startup #ifdef DROPBEAR_ECC_256 -const struct dropbear_ecc_curve ecc_curve_nistp256 = { - .dp = <c_ecc_sets[0], +struct dropbear_ecc_curve ecc_curve_nistp256 = { + .ltc_size = 32, .hashdesc = &sha256_desc, .name = "nistp256" }; #endif #ifdef DROPBEAR_ECC_384 -const struct dropbear_ecc_curve ecc_curve_nistp384 = { - .dp = <c_ecc_sets[1], +struct dropbear_ecc_curve ecc_curve_nistp384 = { + .ltc_size = 48, .hashdesc = &sha384_desc, .name = "nistp384" }; #endif #ifdef DROPBEAR_ECC_521 -const struct dropbear_ecc_curve ecc_curve_nistp521 = { - .dp = <c_ecc_sets[2], +struct dropbear_ecc_curve ecc_curve_nistp521 = { + .ltc_size = 66, .hashdesc = &sha512_desc, .name = "nistp521" }; #endif -static ecc_key * new_ecc_key(void) { +struct dropbear_ecc_curve *dropbear_ecc_curves[] = { +#ifdef DROPBEAR_ECC_256 + &ecc_curve_nistp256, +#endif +#ifdef DROPBEAR_ECC_384 + &ecc_curve_nistp384, +#endif +#ifdef DROPBEAR_ECC_521 + &ecc_curve_nistp521, +#endif + NULL +}; + +void dropbear_ecc_fill_dp() { + struct dropbear_ecc_curve **curve; + // libtomcrypt guarantees they're ordered by size + const ltc_ecc_set_type *dp = ltc_ecc_sets; + for (curve = dropbear_ecc_curves; *curve; curve++) { + for (;dp->size > 0; dp++) { + if (dp->size == (*curve)->ltc_size) { + (*curve)->dp = dp; + break; + } + } + if (!(*curve)->dp) { + dropbear_exit("Missing ECC params %s", (*curve)->name); + } + } +} + +ecc_key * new_ecc_key(void) { ecc_key *key = m_malloc(sizeof(*key)); key->pubkey.x = m_malloc(sizeof(mp_int)); key->pubkey.y = m_malloc(sizeof(mp_int)); @@ -9,14 +9,18 @@ #ifdef DROPBEAR_ECC struct dropbear_ecc_curve { + int ltc_size; // to match the byte sizes in ltc_ecc_sets[] const ltc_ecc_set_type *dp; // curve domain parameters const struct ltc_hash_descriptor *hashdesc; const char *name; }; -extern const struct dropbear_ecc_curve ecc_curve_nistp256; -extern const struct dropbear_ecc_curve ecc_curve_nistp384; -extern const struct dropbear_ecc_curve ecc_curve_nistp521; +extern struct dropbear_ecc_curve ecc_curve_nistp256; +extern struct dropbear_ecc_curve ecc_curve_nistp384; +extern struct dropbear_ecc_curve ecc_curve_nistp521; +extern struct dropbear_ecc_curve *dropbear_ecc_curves[]; + +void dropbear_ecc_fill_dp(); // "pubkey" refers to a point, but LTC uses ecc_key structure for both public // and private keys @@ -1,6 +1,7 @@ #include "includes.h" #include "dbutil.h" #include "crypto_desc.h" +#include "ecc.h" #ifdef DROPBEAR_ECDSA @@ -10,17 +11,17 @@ ecc_key *gen_ecdsa_priv_key(unsigned int bit_size) { switch (bit_size) { #ifdef DROPBEAR_ECC_256 case 256: - dp = <c_ecc_sets[0]; + dp = ecc_curve_nistp256.dp; break; #endif #ifdef DROPBEAR_ECC_384 case 384: - dp = <c_ecc_sets[0]; + dp = ecc_curve_nistp384.dp; break; #endif #ifdef DROPBEAR_ECC_521 case 521: - dp = <c_ecc_sets[0]; + dp = ecc_curve_nistp521.dp; break; #endif } @@ -45,8 +46,54 @@ ecc_key *gen_ecdsa_priv_key(unsigned int bit_size) { return new_key; } -int buf_get_ecdsa_pub_key(buffer* buf, ecc_key *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 = buf_getstring(buf, &key_ident_len); + // string "ecdsa-sha2-[identifier]" + identifier = 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, (*curve)->name, strlen((*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: + if (key_ident) { + m_free(key_ident); + } + if (identifier) { + m_free(identifier); + } + if (q_buf) { + buf_free(q_buf); + q_buf = NULL; + } + TRACE(("leave buf_get_ecdsa_pub_key")) + return new_key; } |