diff options
Diffstat (limited to 'src/irmd/oap/hdr.c')
| -rw-r--r-- | src/irmd/oap/hdr.c | 456 |
1 files changed, 456 insertions, 0 deletions
diff --git a/src/irmd/oap/hdr.c b/src/irmd/oap/hdr.c new file mode 100644 index 00000000..cdff7ab6 --- /dev/null +++ b/src/irmd/oap/hdr.c @@ -0,0 +1,456 @@ +/* + * Ouroboros - Copyright (C) 2016 - 2024 + * + * OAP - Header encoding, decoding, and debugging + * + * Dimitri Staessens <dimitri@ouroboros.rocks> + * Sander Vrijders <sander@ouroboros.rocks> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., http://www.fsf.org/about/contact/. + */ + +#if defined(__linux__) || defined(__CYGWIN__) + #define _DEFAULT_SOURCE +#else + #define _POSIX_C_SOURCE 200809L +#endif + +#define OUROBOROS_PREFIX "irmd/oap" + +#include <ouroboros/crypt.h> +#include <ouroboros/endian.h> +#include <ouroboros/hash.h> +#include <ouroboros/logs.h> +#include <ouroboros/rib.h> +#include <ouroboros/time.h> + +#include "config.h" + +#include "hdr.h" + +#include <assert.h> +#include <errno.h> +#include <stdlib.h> +#include <string.h> +#include <time.h> + +int oap_hdr_decode(struct oap_hdr * oap_hdr, + buffer_t hdr, + int req_md_nid) +{ + off_t offset; + uint16_t kex_len; + uint16_t ciph_nid; + size_t crt_len; + size_t data_len; + size_t hash_len; + size_t sig_len; + + assert(oap_hdr != NULL); + memset(oap_hdr, 0, sizeof(*oap_hdr)); + + if (hdr.len < OAP_HDR_MIN_SIZE) + goto fail_decode; + + /* Parse fixed header (36 bytes) */ + oap_hdr->id.data = hdr.data; + oap_hdr->id.len = OAP_ID_SIZE; + + offset = OAP_ID_SIZE; + + oap_hdr->timestamp = ntoh64(*(uint64_t *)(hdr.data + offset)); + offset += sizeof(uint64_t); + + /* cipher NID */ + ciph_nid = ntoh16(*(uint16_t *)(hdr.data + offset)); + oap_hdr->nid = ciph_nid; + oap_hdr->cipher_str = crypt_nid_to_str(ciph_nid); + offset += sizeof(uint16_t); + + /* kdf NID */ + oap_hdr->kdf_nid = ntoh16(*(uint16_t *)(hdr.data + offset)); + oap_hdr->kdf_str = md_nid_to_str(oap_hdr->kdf_nid); + offset += sizeof(uint16_t); + + /* md NID (signature hash) */ + oap_hdr->md_nid = ntoh16(*(uint16_t *)(hdr.data + offset)); + oap_hdr->md_str = md_nid_to_str(oap_hdr->md_nid); + offset += sizeof(uint16_t); + + /* Validate NIDs: NID_undef is valid at parse time, else must be known. + * Note: md_nid=NID_undef only valid for PQC; enforced at sign/verify. + */ + if (ciph_nid != NID_undef && crypt_validate_nid(ciph_nid) < 0) + goto fail_decode; + if (oap_hdr->kdf_nid != NID_undef && + md_validate_nid(oap_hdr->kdf_nid) < 0) + goto fail_decode; + if (oap_hdr->md_nid != NID_undef && + md_validate_nid(oap_hdr->md_nid) < 0) + goto fail_decode; + + /* crt_len */ + crt_len = (size_t) ntoh16(*(uint16_t *)(hdr.data + offset)); + offset += sizeof(uint16_t); + + /* kex_len + flags */ + kex_len = ntoh16(*(uint16_t *)(hdr.data + offset)); + oap_hdr->kex.len = (size_t) (kex_len & OAP_KEX_LEN_MASK); + oap_hdr->kex_flags.fmt = (kex_len & OAP_KEX_FMT_BIT) ? 1 : 0; + oap_hdr->kex_flags.role = (kex_len & OAP_KEX_ROLE_BIT) ? 1 : 0; + offset += sizeof(uint16_t); + + /* data_len */ + data_len = (size_t) ntoh16(*(uint16_t *)(hdr.data + offset)); + offset += sizeof(uint16_t); + + /* Response includes req_hash when md_nid is set */ + hash_len = (req_md_nid != NID_undef) ? + (size_t) md_len(req_md_nid) : 0; + + /* Validate total length */ + if (hdr.len < (size_t) offset + crt_len + oap_hdr->kex.len + + data_len + hash_len) + goto fail_decode; + + /* Derive sig_len from remaining bytes */ + sig_len = hdr.len - offset - crt_len - oap_hdr->kex.len - + data_len - hash_len; + + /* Unsigned packets must not have trailing bytes */ + if (crt_len == 0 && sig_len != 0) + goto fail_decode; + + /* Parse variable fields */ + oap_hdr->crt.data = hdr.data + offset; + oap_hdr->crt.len = crt_len; + offset += crt_len; + + oap_hdr->kex.data = hdr.data + offset; + offset += oap_hdr->kex.len; + + oap_hdr->data.data = hdr.data + offset; + oap_hdr->data.len = data_len; + offset += data_len; + + oap_hdr->req_hash.data = hdr.data + offset; + oap_hdr->req_hash.len = hash_len; + offset += hash_len; + + oap_hdr->sig.data = hdr.data + offset; + oap_hdr->sig.len = sig_len; + + oap_hdr->hdr = hdr; + + return 0; + + fail_decode: + memset(oap_hdr, 0, sizeof(*oap_hdr)); + return -1; +} + +void oap_hdr_fini(struct oap_hdr * oap_hdr) +{ + assert(oap_hdr != NULL); + + freebuf(oap_hdr->hdr); + memset(oap_hdr, 0, sizeof(*oap_hdr)); +} + +int oap_hdr_copy_data(const struct oap_hdr * hdr, + buffer_t * out) +{ + assert(hdr != NULL); + assert(out != NULL); + + if (hdr->data.len == 0) { + clrbuf(*out); + return 0; + } + + out->data = malloc(hdr->data.len); + if (out->data == NULL) + return -ENOMEM; + + memcpy(out->data, hdr->data.data, hdr->data.len); + out->len = hdr->data.len; + + return 0; +} + +void oap_hdr_init(struct oap_hdr * hdr, + buffer_t id, + uint8_t * kex_buf, + buffer_t data, + uint16_t nid) +{ + assert(hdr != NULL); + assert(id.data != NULL && id.len == OAP_ID_SIZE); + + memset(hdr, 0, sizeof(*hdr)); + + hdr->id = id; + hdr->kex.data = kex_buf; + hdr->kex.len = 0; + hdr->data = data; + hdr->nid = nid; +} + +int oap_hdr_encode(struct oap_hdr * hdr, + void * pkp, + void * crt, + struct sec_config * kcfg, + buffer_t req_hash, + int req_md_nid) +{ + struct timespec now; + uint64_t stamp; + buffer_t out; + buffer_t der = BUF_INIT; + buffer_t sig = BUF_INIT; + buffer_t sign; + uint16_t len; + uint16_t ciph_nid; + uint16_t kdf_nid; + uint16_t md_nid; + uint16_t kex_len; + off_t offset; + + assert(hdr != NULL); + assert(hdr->id.data != NULL && hdr->id.len == OAP_ID_SIZE); + assert(kcfg != NULL); + + clock_gettime(CLOCK_REALTIME, &now); + stamp = hton64(TS_TO_UINT64(now)); + + if (crt != NULL && crypt_crt_der(crt, &der) < 0) + goto fail_der; + + ciph_nid = hton16(hdr->nid); + kdf_nid = hton16(kcfg->k.nid); + md_nid = hton16(kcfg->d.nid); + + /* Build kex_len with flags */ + kex_len = (uint16_t) hdr->kex.len; + if (hdr->kex.len > 0 && IS_KEM_ALGORITHM(kcfg->x.str)) { + if (IS_HYBRID_KEM(kcfg->x.str)) + kex_len |= OAP_KEX_FMT_BIT; + if (kcfg->x.mode == KEM_MODE_CLIENT_ENCAP) + kex_len |= OAP_KEX_ROLE_BIT; + } + kex_len = hton16(kex_len); + + /* Fixed header (36 bytes) + variable fields + req_hash (if auth) */ + out.len = OAP_HDR_MIN_SIZE + der.len + hdr->kex.len + hdr->data.len + + req_hash.len; + + out.data = malloc(out.len); + if (out.data == NULL) + goto fail_out; + + offset = 0; + + /* id (16 bytes) */ + memcpy(out.data + offset, hdr->id.data, hdr->id.len); + offset += hdr->id.len; + + /* timestamp (8 bytes) */ + memcpy(out.data + offset, &stamp, sizeof(stamp)); + offset += sizeof(stamp); + + /* cipher_nid (2 bytes) */ + memcpy(out.data + offset, &ciph_nid, sizeof(ciph_nid)); + offset += sizeof(ciph_nid); + + /* kdf_nid (2 bytes) */ + memcpy(out.data + offset, &kdf_nid, sizeof(kdf_nid)); + offset += sizeof(kdf_nid); + + /* md_nid (2 bytes) */ + memcpy(out.data + offset, &md_nid, sizeof(md_nid)); + offset += sizeof(md_nid); + + /* crt_len (2 bytes) */ + len = hton16((uint16_t) der.len); + memcpy(out.data + offset, &len, sizeof(len)); + offset += sizeof(len); + + /* kex_len + flags (2 bytes) */ + memcpy(out.data + offset, &kex_len, sizeof(kex_len)); + offset += sizeof(kex_len); + + /* data_len (2 bytes) */ + len = hton16((uint16_t) hdr->data.len); + memcpy(out.data + offset, &len, sizeof(len)); + offset += sizeof(len); + + /* Fixed header complete (36 bytes) */ + assert((size_t) offset == OAP_HDR_MIN_SIZE); + + /* certificate (variable) */ + if (der.len != 0) + memcpy(out.data + offset, der.data, der.len); + offset += der.len; + + /* kex data (variable) */ + if (hdr->kex.len != 0) + memcpy(out.data + offset, hdr->kex.data, hdr->kex.len); + offset += hdr->kex.len; + + /* data (variable) */ + if (hdr->data.len != 0) + memcpy(out.data + offset, hdr->data.data, hdr->data.len); + offset += hdr->data.len; + + /* req_hash (variable, only for authenticated responses) */ + if (req_hash.len != 0) + memcpy(out.data + offset, req_hash.data, req_hash.len); + offset += req_hash.len; + + assert((size_t) offset == out.len); + + /* Sign the entire header (fixed + variable, excluding signature) */ + sign.data = out.data; + sign.len = out.len; + + if (pkp != NULL && auth_sign(pkp, kcfg->d.nid, sign, &sig) < 0) + goto fail_sig; + + hdr->hdr = out; + + /* Append signature */ + if (sig.len > 0) { + hdr->hdr.len += sig.len; + hdr->hdr.data = realloc(out.data, hdr->hdr.len); + if (hdr->hdr.data == NULL) + goto fail_realloc; + + memcpy(hdr->hdr.data + offset, sig.data, sig.len); + clrbuf(out); + } + + if (oap_hdr_decode(hdr, hdr->hdr, req_md_nid) < 0) + goto fail_decode; + + freebuf(der); + freebuf(sig); + + return 0; + + fail_decode: + oap_hdr_fini(hdr); + fail_realloc: + freebuf(sig); + fail_sig: + freebuf(out); + fail_out: + freebuf(der); + fail_der: + return -1; +} + +#ifdef DEBUG_PROTO_OAP +static void debug_oap_hdr(const struct oap_hdr * hdr) +{ + assert(hdr); + + if (hdr->crt.len > 0) + log_proto(" crt: [%zu bytes]", hdr->crt.len); + else + log_proto(" crt: <none>"); + + if (hdr->kex.len > 0) + log_proto(" Key Exchange Data: [%zu bytes] [%s]", + hdr->kex.len, hdr->kex_flags.role ? + "Client encaps" : "Server encaps"); + else + log_proto(" Ephemeral Public Key: <none>"); + + if (hdr->cipher_str != NULL) + log_proto(" Cipher: %s", hdr->cipher_str); + else + log_proto(" Cipher: <none>"); + + if (hdr->kdf_str != NULL) + log_proto(" KDF: HKDF-%s", hdr->kdf_str); + else + log_proto(" KDF: <none>"); + + if (hdr->md_str != NULL) + log_proto(" Digest: %s", hdr->md_str); + else + log_proto(" Digest: <none>"); + + if (hdr->data.len > 0) + log_proto(" Data: [%zu bytes]", hdr->data.len); + else + log_proto(" Data: <none>"); + + if (hdr->req_hash.len > 0) + log_proto(" Req Hash: [%zu bytes]", hdr->req_hash.len); + else + log_proto(" Req Hash: <none>"); + + if (hdr->sig.len > 0) + log_proto(" Signature: [%zu bytes]", hdr->sig.len); + else + log_proto(" Signature: <none>"); +} +#endif + +void debug_oap_hdr_rcv(const struct oap_hdr * hdr) +{ +#ifdef DEBUG_PROTO_OAP + struct tm * tm; + char tmstr[RIB_TM_STRLEN]; + time_t stamp; + + assert(hdr); + + stamp = (time_t) hdr->timestamp / BILLION; + + tm = gmtime(&stamp); + strftime(tmstr, sizeof(tmstr), RIB_TM_FORMAT, tm); + + log_proto("OAP_HDR [" HASH_FMT64 " @ %s ] <--", + HASH_VAL64(hdr->id.data), tmstr); + + debug_oap_hdr(hdr); +#else + (void) hdr; +#endif +} + +void debug_oap_hdr_snd(const struct oap_hdr * hdr) +{ +#ifdef DEBUG_PROTO_OAP + struct tm * tm; + char tmstr[RIB_TM_STRLEN]; + time_t stamp; + + assert(hdr); + + stamp = (time_t) hdr->timestamp / BILLION; + + tm = gmtime(&stamp); + strftime(tmstr, sizeof(tmstr), RIB_TM_FORMAT, tm); + + log_proto("OAP_HDR [" HASH_FMT64 " @ %s ] -->", + HASH_VAL64(hdr->id.data), tmstr); + + debug_oap_hdr(hdr); +#else + (void) hdr; +#endif +} |