| /* |
| * Copyright (c) 2012 Damien Miller <djm@mindrot.org> |
| * |
| * Permission to use, copy, modify, and distribute this software for any |
| * purpose with or without fee is hereby granted, provided that the above |
| * copyright notice and this permission notice appear in all copies. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
| * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
| * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| */ |
| |
| /* $OpenBSD: krl.c,v 1.5 2013/01/24 21:45:37 djm Exp $ */ |
| |
| #include "includes.h" |
| |
| #include <sys/types.h> |
| #include <sys/param.h> |
| #include <openbsd-compat/sys-tree.h> |
| #include <openbsd-compat/sys-queue.h> |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <limits.h> |
| #include <string.h> |
| #include <time.h> |
| #include <unistd.h> |
| |
| #include "buffer.h" |
| #include "key.h" |
| #include "authfile.h" |
| #include "err.h" |
| #include "misc.h" |
| #include "log.h" |
| #include "xmalloc.h" |
| |
| #include "krl.h" |
| |
| /* #define DEBUG_KRL */ |
| #ifdef DEBUG_KRL |
| # define KRL_DBG(x) debug3 x |
| #else |
| # define KRL_DBG(x) |
| #endif |
| |
| /* |
| * Trees of revoked serial numbers, key IDs and keys. This allows |
| * quick searching, querying and producing lists in canonical order. |
| */ |
| |
| /* Tree of serial numbers. XXX make smarter: really need a real sparse bitmap */ |
| struct revoked_serial { |
| u_int64_t lo, hi; |
| RB_ENTRY(revoked_serial) tree_entry; |
| }; |
| static int serial_cmp(struct revoked_serial *a, struct revoked_serial *b); |
| RB_HEAD(revoked_serial_tree, revoked_serial); |
| RB_GENERATE_STATIC(revoked_serial_tree, revoked_serial, tree_entry, serial_cmp); |
| |
| /* Tree of key IDs */ |
| struct revoked_key_id { |
| char *key_id; |
| RB_ENTRY(revoked_key_id) tree_entry; |
| }; |
| static int key_id_cmp(struct revoked_key_id *a, struct revoked_key_id *b); |
| RB_HEAD(revoked_key_id_tree, revoked_key_id); |
| RB_GENERATE_STATIC(revoked_key_id_tree, revoked_key_id, tree_entry, key_id_cmp); |
| |
| /* Tree of blobs (used for keys and fingerprints) */ |
| struct revoked_blob { |
| u_char *blob; |
| u_int len; |
| RB_ENTRY(revoked_blob) tree_entry; |
| }; |
| static int blob_cmp(struct revoked_blob *a, struct revoked_blob *b); |
| RB_HEAD(revoked_blob_tree, revoked_blob); |
| RB_GENERATE_STATIC(revoked_blob_tree, revoked_blob, tree_entry, blob_cmp); |
| |
| /* Tracks revoked certs for a single CA */ |
| struct revoked_certs { |
| Key *ca_key; |
| struct revoked_serial_tree revoked_serials; |
| struct revoked_key_id_tree revoked_key_ids; |
| TAILQ_ENTRY(revoked_certs) entry; |
| }; |
| TAILQ_HEAD(revoked_certs_list, revoked_certs); |
| |
| struct ssh_krl { |
| u_int64_t krl_version; |
| u_int64_t generated_date; |
| u_int64_t flags; |
| char *comment; |
| struct revoked_blob_tree revoked_keys; |
| struct revoked_blob_tree revoked_sha1s; |
| struct revoked_certs_list revoked_certs; |
| }; |
| |
| /* Return equal if a and b overlap */ |
| static int |
| serial_cmp(struct revoked_serial *a, struct revoked_serial *b) |
| { |
| if (a->hi >= b->lo && a->lo <= b->hi) |
| return 0; |
| return a->lo < b->lo ? -1 : 1; |
| } |
| |
| static int |
| key_id_cmp(struct revoked_key_id *a, struct revoked_key_id *b) |
| { |
| return strcmp(a->key_id, b->key_id); |
| } |
| |
| static int |
| blob_cmp(struct revoked_blob *a, struct revoked_blob *b) |
| { |
| int r; |
| |
| if (a->len != b->len) { |
| if ((r = memcmp(a->blob, b->blob, MIN(a->len, b->len))) != 0) |
| return r; |
| return a->len > b->len ? 1 : -1; |
| } else |
| return memcmp(a->blob, b->blob, a->len); |
| } |
| |
| struct ssh_krl * |
| ssh_krl_init(void) |
| { |
| struct ssh_krl *krl; |
| |
| if ((krl = calloc(1, sizeof(*krl))) == NULL) |
| return NULL; |
| RB_INIT(&krl->revoked_keys); |
| RB_INIT(&krl->revoked_sha1s); |
| TAILQ_INIT(&krl->revoked_certs); |
| return krl; |
| } |
| |
| static void |
| revoked_certs_free(struct revoked_certs *rc) |
| { |
| struct revoked_serial *rs, *trs; |
| struct revoked_key_id *rki, *trki; |
| |
| RB_FOREACH_SAFE(rs, revoked_serial_tree, &rc->revoked_serials, trs) { |
| RB_REMOVE(revoked_serial_tree, &rc->revoked_serials, rs); |
| free(rs); |
| } |
| RB_FOREACH_SAFE(rki, revoked_key_id_tree, &rc->revoked_key_ids, trki) { |
| RB_REMOVE(revoked_key_id_tree, &rc->revoked_key_ids, rki); |
| free(rki->key_id); |
| free(rki); |
| } |
| if (rc->ca_key != NULL) |
| key_free(rc->ca_key); |
| } |
| |
| void |
| ssh_krl_free(struct ssh_krl *krl) |
| { |
| struct revoked_blob *rb, *trb; |
| struct revoked_certs *rc, *trc; |
| |
| if (krl == NULL) |
| return; |
| |
| free(krl->comment); |
| RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_keys, trb) { |
| RB_REMOVE(revoked_blob_tree, &krl->revoked_keys, rb); |
| free(rb->blob); |
| free(rb); |
| } |
| RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_sha1s, trb) { |
| RB_REMOVE(revoked_blob_tree, &krl->revoked_sha1s, rb); |
| free(rb->blob); |
| free(rb); |
| } |
| TAILQ_FOREACH_SAFE(rc, &krl->revoked_certs, entry, trc) { |
| TAILQ_REMOVE(&krl->revoked_certs, rc, entry); |
| revoked_certs_free(rc); |
| } |
| } |
| |
| void |
| ssh_krl_set_version(struct ssh_krl *krl, u_int64_t version) |
| { |
| krl->krl_version = version; |
| } |
| |
| void |
| ssh_krl_set_comment(struct ssh_krl *krl, const char *comment) |
| { |
| free(krl->comment); |
| if ((krl->comment = strdup(comment)) == NULL) |
| fatal("%s: strdup", __func__); |
| } |
| |
| /* |
| * Find the revoked_certs struct for a CA key. If allow_create is set then |
| * create a new one in the tree if one did not exist already. |
| */ |
| static int |
| revoked_certs_for_ca_key(struct ssh_krl *krl, const Key *ca_key, |
| struct revoked_certs **rcp, int allow_create) |
| { |
| struct revoked_certs *rc; |
| |
| *rcp = NULL; |
| TAILQ_FOREACH(rc, &krl->revoked_certs, entry) { |
| if (key_equal(rc->ca_key, ca_key)) { |
| *rcp = rc; |
| return 0; |
| } |
| } |
| if (!allow_create) |
| return 0; |
| /* If this CA doesn't exist in the list then add it now */ |
| if ((rc = calloc(1, sizeof(*rc))) == NULL) |
| return -1; |
| if ((rc->ca_key = key_from_private(ca_key)) == NULL) { |
| free(rc); |
| return -1; |
| } |
| RB_INIT(&rc->revoked_serials); |
| RB_INIT(&rc->revoked_key_ids); |
| TAILQ_INSERT_TAIL(&krl->revoked_certs, rc, entry); |
| debug3("%s: new CA %s", __func__, key_type(ca_key)); |
| *rcp = rc; |
| return 0; |
| } |
| |
| static int |
| insert_serial_range(struct revoked_serial_tree *rt, u_int64_t lo, u_int64_t hi) |
| { |
| struct revoked_serial rs, *ers, *crs, *irs; |
| |
| KRL_DBG(("%s: insert %llu:%llu", __func__, lo, hi)); |
| bzero(&rs, sizeof(rs)); |
| rs.lo = lo; |
| rs.hi = hi; |
| ers = RB_NFIND(revoked_serial_tree, rt, &rs); |
| if (ers == NULL || serial_cmp(ers, &rs) != 0) { |
| /* No entry matches. Just insert */ |
| if ((irs = malloc(sizeof(rs))) == NULL) |
| return -1; |
| memcpy(irs, &rs, sizeof(*irs)); |
| ers = RB_INSERT(revoked_serial_tree, rt, irs); |
| if (ers != NULL) { |
| KRL_DBG(("%s: bad: ers != NULL", __func__)); |
| /* Shouldn't happen */ |
| free(irs); |
| return -1; |
| } |
| ers = irs; |
| } else { |
| KRL_DBG(("%s: overlap found %llu:%llu", __func__, |
| ers->lo, ers->hi)); |
| /* |
| * The inserted entry overlaps an existing one. Grow the |
| * existing entry. |
| */ |
| if (ers->lo > lo) |
| ers->lo = lo; |
| if (ers->hi < hi) |
| ers->hi = hi; |
| } |
| /* |
| * The inserted or revised range might overlap or abut adjacent ones; |
| * coalesce as necessary. |
| */ |
| |
| /* Check predecessors */ |
| while ((crs = RB_PREV(revoked_serial_tree, rt, ers)) != NULL) { |
| KRL_DBG(("%s: pred %llu:%llu", __func__, crs->lo, crs->hi)); |
| if (ers->lo != 0 && crs->hi < ers->lo - 1) |
| break; |
| /* This entry overlaps. */ |
| if (crs->lo < ers->lo) { |
| ers->lo = crs->lo; |
| KRL_DBG(("%s: pred extend %llu:%llu", __func__, |
| ers->lo, ers->hi)); |
| } |
| RB_REMOVE(revoked_serial_tree, rt, crs); |
| free(crs); |
| } |
| /* Check successors */ |
| while ((crs = RB_NEXT(revoked_serial_tree, rt, ers)) != NULL) { |
| KRL_DBG(("%s: succ %llu:%llu", __func__, crs->lo, crs->hi)); |
| if (ers->hi != (u_int64_t)-1 && crs->lo > ers->hi + 1) |
| break; |
| /* This entry overlaps. */ |
| if (crs->hi > ers->hi) { |
| ers->hi = crs->hi; |
| KRL_DBG(("%s: succ extend %llu:%llu", __func__, |
| ers->lo, ers->hi)); |
| } |
| RB_REMOVE(revoked_serial_tree, rt, crs); |
| free(crs); |
| } |
| KRL_DBG(("%s: done, final %llu:%llu", __func__, ers->lo, ers->hi)); |
| return 0; |
| } |
| |
| int |
| ssh_krl_revoke_cert_by_serial(struct ssh_krl *krl, const Key *ca_key, |
| u_int64_t serial) |
| { |
| return ssh_krl_revoke_cert_by_serial_range(krl, ca_key, serial, serial); |
| } |
| |
| int |
| ssh_krl_revoke_cert_by_serial_range(struct ssh_krl *krl, const Key *ca_key, |
| u_int64_t lo, u_int64_t hi) |
| { |
| struct revoked_certs *rc; |
| |
| if (lo > hi || lo == 0) |
| return -1; |
| if (revoked_certs_for_ca_key(krl, ca_key, &rc, 1) != 0) |
| return -1; |
| return insert_serial_range(&rc->revoked_serials, lo, hi); |
| } |
| |
| int |
| ssh_krl_revoke_cert_by_key_id(struct ssh_krl *krl, const Key *ca_key, |
| const char *key_id) |
| { |
| struct revoked_key_id *rki, *erki; |
| struct revoked_certs *rc; |
| |
| if (revoked_certs_for_ca_key(krl, ca_key, &rc, 1) != 0) |
| return -1; |
| |
| debug3("%s: revoke %s", __func__, key_id); |
| if ((rki = calloc(1, sizeof(*rki))) == NULL || |
| (rki->key_id = strdup(key_id)) == NULL) { |
| free(rki); |
| fatal("%s: strdup", __func__); |
| } |
| erki = RB_INSERT(revoked_key_id_tree, &rc->revoked_key_ids, rki); |
| if (erki != NULL) { |
| free(rki->key_id); |
| free(rki); |
| } |
| return 0; |
| } |
| |
| /* Convert "key" to a public key blob without any certificate information */ |
| static int |
| plain_key_blob(const Key *key, u_char **blob, u_int *blen) |
| { |
| Key *kcopy; |
| int r; |
| |
| if ((kcopy = key_from_private(key)) == NULL) |
| return -1; |
| if (key_is_cert(kcopy)) { |
| if (key_drop_cert(kcopy) != 0) { |
| error("%s: key_drop_cert", __func__); |
| key_free(kcopy); |
| return -1; |
| } |
| } |
| r = key_to_blob(kcopy, blob, blen); |
| free(kcopy); |
| return r == 0 ? -1 : 0; |
| } |
| |
| /* Revoke a key blob. Ownership of blob is transferred to the tree */ |
| static int |
| revoke_blob(struct revoked_blob_tree *rbt, u_char *blob, u_int len) |
| { |
| struct revoked_blob *rb, *erb; |
| |
| if ((rb = calloc(1, sizeof(*rb))) == NULL) |
| return -1; |
| rb->blob = blob; |
| rb->len = len; |
| erb = RB_INSERT(revoked_blob_tree, rbt, rb); |
| if (erb != NULL) { |
| free(rb->blob); |
| free(rb); |
| } |
| return 0; |
| } |
| |
| int |
| ssh_krl_revoke_key_explicit(struct ssh_krl *krl, const Key *key) |
| { |
| u_char *blob; |
| u_int len; |
| |
| debug3("%s: revoke type %s", __func__, key_type(key)); |
| if (plain_key_blob(key, &blob, &len) != 0) |
| return -1; |
| return revoke_blob(&krl->revoked_keys, blob, len); |
| } |
| |
| int |
| ssh_krl_revoke_key_sha1(struct ssh_krl *krl, const Key *key) |
| { |
| u_char *blob; |
| u_int len; |
| |
| debug3("%s: revoke type %s by sha1", __func__, key_type(key)); |
| if ((blob = key_fingerprint_raw(key, SSH_FP_SHA1, &len)) == NULL) |
| return -1; |
| return revoke_blob(&krl->revoked_sha1s, blob, len); |
| } |
| |
| int |
| ssh_krl_revoke_key(struct ssh_krl *krl, const Key *key) |
| { |
| if (!key_is_cert(key)) |
| return ssh_krl_revoke_key_sha1(krl, key); |
| |
| if (key_cert_is_legacy(key) || key->cert->serial == 0) { |
| return ssh_krl_revoke_cert_by_key_id(krl, |
| key->cert->signature_key, |
| key->cert->key_id); |
| } else { |
| return ssh_krl_revoke_cert_by_serial(krl, |
| key->cert->signature_key, |
| key->cert->serial); |
| } |
| } |
| |
| /* |
| * Select a copact next section type to emit in a KRL based on the |
| * current section type, the run length of contiguous revoked serial |
| * numbers and the gaps from the last and to the next revoked serial. |
| * Applies a mostly-accurate bit cost model to select the section type |
| * that will minimise the size of the resultant KRL. |
| */ |
| static int |
| choose_next_state(int current_state, u_int64_t contig, int final, |
| u_int64_t last_gap, u_int64_t next_gap, int *force_new_section) |
| { |
| int new_state; |
| u_int64_t cost, cost_list, cost_range, cost_bitmap, cost_bitmap_restart; |
| |
| /* |
| * Avoid unsigned overflows. |
| * The limits are high enough to avoid confusing the calculations. |
| */ |
| contig = MIN(contig, 1ULL<<31); |
| last_gap = MIN(last_gap, 1ULL<<31); |
| next_gap = MIN(next_gap, 1ULL<<31); |
| |
| /* |
| * Calculate the cost to switch from the current state to candidates. |
| * NB. range sections only ever contain a single range, so their |
| * switching cost is independent of the current_state. |
| */ |
| cost_list = cost_bitmap = cost_bitmap_restart = 0; |
| cost_range = 8; |
| switch (current_state) { |
| case KRL_SECTION_CERT_SERIAL_LIST: |
| cost_bitmap_restart = cost_bitmap = 8 + 64; |
| break; |
| case KRL_SECTION_CERT_SERIAL_BITMAP: |
| cost_list = 8; |
| cost_bitmap_restart = 8 + 64; |
| break; |
| case KRL_SECTION_CERT_SERIAL_RANGE: |
| case 0: |
| cost_bitmap_restart = cost_bitmap = 8 + 64; |
| cost_list = 8; |
| } |
| |
| /* Estimate base cost in bits of each section type */ |
| cost_list += 64 * contig + (final ? 0 : 8+64); |
| cost_range += (2 * 64) + (final ? 0 : 8+64); |
| cost_bitmap += last_gap + contig + (final ? 0 : MIN(next_gap, 8+64)); |
| cost_bitmap_restart += contig + (final ? 0 : MIN(next_gap, 8+64)); |
| |
| /* Convert to byte costs for actual comparison */ |
| cost_list = (cost_list + 7) / 8; |
| cost_bitmap = (cost_bitmap + 7) / 8; |
| cost_bitmap_restart = (cost_bitmap_restart + 7) / 8; |
| cost_range = (cost_range + 7) / 8; |
| |
| /* Now pick the best choice */ |
| *force_new_section = 0; |
| new_state = KRL_SECTION_CERT_SERIAL_BITMAP; |
| cost = cost_bitmap; |
| if (cost_range < cost) { |
| new_state = KRL_SECTION_CERT_SERIAL_RANGE; |
| cost = cost_range; |
| } |
| if (cost_list < cost) { |
| new_state = KRL_SECTION_CERT_SERIAL_LIST; |
| cost = cost_list; |
| } |
| if (cost_bitmap_restart < cost) { |
| new_state = KRL_SECTION_CERT_SERIAL_BITMAP; |
| *force_new_section = 1; |
| cost = cost_bitmap_restart; |
| } |
| debug3("%s: contig %llu last_gap %llu next_gap %llu final %d, costs:" |
| "list %llu range %llu bitmap %llu new bitmap %llu, " |
| "selected 0x%02x%s", __func__, contig, last_gap, next_gap, final, |
| cost_list, cost_range, cost_bitmap, cost_bitmap_restart, new_state, |
| *force_new_section ? " restart" : ""); |
| return new_state; |
| } |
| |
| /* Generate a KRL_SECTION_CERTIFICATES KRL section */ |
| static int |
| revoked_certs_generate(struct revoked_certs *rc, Buffer *buf) |
| { |
| int final, force_new_sect, r = -1; |
| u_int64_t i, contig, gap, last = 0, bitmap_start = 0; |
| struct revoked_serial *rs, *nrs; |
| struct revoked_key_id *rki; |
| int next_state, state = 0; |
| Buffer sect; |
| u_char *kblob = NULL; |
| u_int klen; |
| BIGNUM *bitmap = NULL; |
| |
| /* Prepare CA scope key blob if we have one supplied */ |
| if (key_to_blob(rc->ca_key, &kblob, &klen) == 0) |
| return -1; |
| |
| buffer_init(§); |
| |
| /* Store the header */ |
| buffer_put_string(buf, kblob, klen); |
| buffer_put_string(buf, NULL, 0); /* Reserved */ |
| |
| free(kblob); |
| |
| /* Store the revoked serials. */ |
| for (rs = RB_MIN(revoked_serial_tree, &rc->revoked_serials); |
| rs != NULL; |
| rs = RB_NEXT(revoked_serial_tree, &rc->revoked_serials, rs)) { |
| debug3("%s: serial %llu:%llu state 0x%02x", __func__, |
| rs->lo, rs->hi, state); |
| |
| /* Check contiguous length and gap to next section (if any) */ |
| nrs = RB_NEXT(revoked_serial_tree, &rc->revoked_serials, rs); |
| final = nrs == NULL; |
| gap = nrs == NULL ? 0 : nrs->lo - rs->hi; |
| contig = 1 + (rs->hi - rs->lo); |
| |
| /* Choose next state based on these */ |
| next_state = choose_next_state(state, contig, final, |
| state == 0 ? 0 : rs->lo - last, gap, &force_new_sect); |
| |
| /* |
| * If the current section is a range section or has a different |
| * type to the next section, then finish it off now. |
| */ |
| if (state != 0 && (force_new_sect || next_state != state || |
| state == KRL_SECTION_CERT_SERIAL_RANGE)) { |
| debug3("%s: finish state 0x%02x", __func__, state); |
| switch (state) { |
| case KRL_SECTION_CERT_SERIAL_LIST: |
| case KRL_SECTION_CERT_SERIAL_RANGE: |
| break; |
| case KRL_SECTION_CERT_SERIAL_BITMAP: |
| buffer_put_bignum2(§, bitmap); |
| BN_free(bitmap); |
| bitmap = NULL; |
| break; |
| } |
| buffer_put_char(buf, state); |
| buffer_put_string(buf, |
| buffer_ptr(§), buffer_len(§)); |
| } |
| |
| /* If we are starting a new section then prepare it now */ |
| if (next_state != state || force_new_sect) { |
| debug3("%s: start state 0x%02x", __func__, next_state); |
| state = next_state; |
| buffer_clear(§); |
| switch (state) { |
| case KRL_SECTION_CERT_SERIAL_LIST: |
| case KRL_SECTION_CERT_SERIAL_RANGE: |
| break; |
| case KRL_SECTION_CERT_SERIAL_BITMAP: |
| if ((bitmap = BN_new()) == NULL) |
| goto out; |
| bitmap_start = rs->lo; |
| buffer_put_int64(§, bitmap_start); |
| break; |
| } |
| } |
| |
| /* Perform section-specific processing */ |
| switch (state) { |
| case KRL_SECTION_CERT_SERIAL_LIST: |
| for (i = 0; i < contig; i++) |
| buffer_put_int64(§, rs->lo + i); |
| break; |
| case KRL_SECTION_CERT_SERIAL_RANGE: |
| buffer_put_int64(§, rs->lo); |
| buffer_put_int64(§, rs->hi); |
| break; |
| case KRL_SECTION_CERT_SERIAL_BITMAP: |
| if (rs->lo - bitmap_start > INT_MAX) { |
| error("%s: insane bitmap gap", __func__); |
| goto out; |
| } |
| for (i = 0; i < contig; i++) { |
| if (BN_set_bit(bitmap, |
| rs->lo + i - bitmap_start) != 1) |
| goto out; |
| } |
| break; |
| } |
| last = rs->hi; |
| } |
| /* Flush the remaining section, if any */ |
| if (state != 0) { |
| debug3("%s: serial final flush for state 0x%02x", |
| __func__, state); |
| switch (state) { |
| case KRL_SECTION_CERT_SERIAL_LIST: |
| case KRL_SECTION_CERT_SERIAL_RANGE: |
| break; |
| case KRL_SECTION_CERT_SERIAL_BITMAP: |
| buffer_put_bignum2(§, bitmap); |
| BN_free(bitmap); |
| bitmap = NULL; |
| break; |
| } |
| buffer_put_char(buf, state); |
| buffer_put_string(buf, |
| buffer_ptr(§), buffer_len(§)); |
| } |
| debug3("%s: serial done ", __func__); |
| |
| /* Now output a section for any revocations by key ID */ |
| buffer_clear(§); |
| RB_FOREACH(rki, revoked_key_id_tree, &rc->revoked_key_ids) { |
| debug3("%s: key ID %s", __func__, rki->key_id); |
| buffer_put_cstring(§, rki->key_id); |
| } |
| if (buffer_len(§) != 0) { |
| buffer_put_char(buf, KRL_SECTION_CERT_KEY_ID); |
| buffer_put_string(buf, buffer_ptr(§), |
| buffer_len(§)); |
| } |
| r = 0; |
| out: |
| if (bitmap != NULL) |
| BN_free(bitmap); |
| buffer_free(§); |
| return r; |
| } |
| |
| int |
| ssh_krl_to_blob(struct ssh_krl *krl, Buffer *buf, const Key **sign_keys, |
| u_int nsign_keys) |
| { |
| int r = -1; |
| struct revoked_certs *rc; |
| struct revoked_blob *rb; |
| Buffer sect; |
| u_char *kblob = NULL, *sblob = NULL; |
| u_int klen, slen, i; |
| |
| if (krl->generated_date == 0) |
| krl->generated_date = time(NULL); |
| |
| buffer_init(§); |
| |
| /* Store the header */ |
| buffer_append(buf, KRL_MAGIC, sizeof(KRL_MAGIC) - 1); |
| buffer_put_int(buf, KRL_FORMAT_VERSION); |
| buffer_put_int64(buf, krl->krl_version); |
| buffer_put_int64(buf, krl->generated_date); |
| buffer_put_int64(buf, krl->flags); |
| buffer_put_string(buf, NULL, 0); |
| buffer_put_cstring(buf, krl->comment ? krl->comment : ""); |
| |
| /* Store sections for revoked certificates */ |
| TAILQ_FOREACH(rc, &krl->revoked_certs, entry) { |
| if (revoked_certs_generate(rc, §) != 0) |
| goto out; |
| buffer_put_char(buf, KRL_SECTION_CERTIFICATES); |
| buffer_put_string(buf, buffer_ptr(§), |
| buffer_len(§)); |
| } |
| |
| /* Finally, output sections for revocations by public key/hash */ |
| buffer_clear(§); |
| RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_keys) { |
| debug3("%s: key len %u ", __func__, rb->len); |
| buffer_put_string(§, rb->blob, rb->len); |
| } |
| if (buffer_len(§) != 0) { |
| buffer_put_char(buf, KRL_SECTION_EXPLICIT_KEY); |
| buffer_put_string(buf, buffer_ptr(§), |
| buffer_len(§)); |
| } |
| buffer_clear(§); |
| RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha1s) { |
| debug3("%s: hash len %u ", __func__, rb->len); |
| buffer_put_string(§, rb->blob, rb->len); |
| } |
| if (buffer_len(§) != 0) { |
| buffer_put_char(buf, KRL_SECTION_FINGERPRINT_SHA1); |
| buffer_put_string(buf, buffer_ptr(§), |
| buffer_len(§)); |
| } |
| |
| for (i = 0; i < nsign_keys; i++) { |
| if (key_to_blob(sign_keys[i], &kblob, &klen) == 0) |
| goto out; |
| |
| debug3("%s: signature key len %u", __func__, klen); |
| buffer_put_char(buf, KRL_SECTION_SIGNATURE); |
| buffer_put_string(buf, kblob, klen); |
| |
| if (key_sign(sign_keys[i], &sblob, &slen, |
| buffer_ptr(buf), buffer_len(buf)) == -1) |
| goto out; |
| debug3("%s: signature sig len %u", __func__, slen); |
| buffer_put_string(buf, sblob, slen); |
| } |
| |
| r = 0; |
| out: |
| free(kblob); |
| free(sblob); |
| buffer_free(§); |
| return r; |
| } |
| |
| static void |
| format_timestamp(u_int64_t timestamp, char *ts, size_t nts) |
| { |
| time_t t; |
| struct tm *tm; |
| |
| t = timestamp; |
| tm = localtime(&t); |
| *ts = '\0'; |
| strftime(ts, nts, "%Y%m%dT%H%M%S", tm); |
| } |
| |
| static int |
| parse_revoked_certs(Buffer *buf, struct ssh_krl *krl) |
| { |
| int ret = -1, nbits; |
| u_char type, *blob; |
| u_int blen; |
| Buffer subsect; |
| u_int64_t serial, serial_lo, serial_hi; |
| BIGNUM *bitmap = NULL; |
| char *key_id = NULL; |
| Key *ca_key = NULL; |
| |
| buffer_init(&subsect); |
| |
| if ((blob = buffer_get_string_ptr_ret(buf, &blen)) == NULL || |
| buffer_get_string_ptr_ret(buf, NULL) == NULL) { /* reserved */ |
| error("%s: buffer error", __func__); |
| goto out; |
| } |
| if ((ca_key = key_from_blob(blob, blen)) == NULL) |
| goto out; |
| |
| while (buffer_len(buf) > 0) { |
| if (buffer_get_char_ret(&type, buf) != 0 || |
| (blob = buffer_get_string_ptr_ret(buf, &blen)) == NULL) { |
| error("%s: buffer error", __func__); |
| goto out; |
| } |
| buffer_clear(&subsect); |
| buffer_append(&subsect, blob, blen); |
| debug3("%s: subsection type 0x%02x", __func__, type); |
| /* buffer_dump(&subsect); */ |
| |
| switch (type) { |
| case KRL_SECTION_CERT_SERIAL_LIST: |
| while (buffer_len(&subsect) > 0) { |
| if (buffer_get_int64_ret(&serial, |
| &subsect) != 0) { |
| error("%s: buffer error", __func__); |
| goto out; |
| } |
| if (ssh_krl_revoke_cert_by_serial(krl, ca_key, |
| serial) != 0) { |
| error("%s: update failed", __func__); |
| goto out; |
| } |
| } |
| break; |
| case KRL_SECTION_CERT_SERIAL_RANGE: |
| if (buffer_get_int64_ret(&serial_lo, &subsect) != 0 || |
| buffer_get_int64_ret(&serial_hi, &subsect) != 0) { |
| error("%s: buffer error", __func__); |
| goto out; |
| } |
| if (ssh_krl_revoke_cert_by_serial_range(krl, ca_key, |
| serial_lo, serial_hi) != 0) { |
| error("%s: update failed", __func__); |
| goto out; |
| } |
| break; |
| case KRL_SECTION_CERT_SERIAL_BITMAP: |
| if ((bitmap = BN_new()) == NULL) { |
| error("%s: BN_new", __func__); |
| goto out; |
| } |
| if (buffer_get_int64_ret(&serial_lo, &subsect) != 0 || |
| buffer_get_bignum2_ret(&subsect, bitmap) != 0) { |
| error("%s: buffer error", __func__); |
| goto out; |
| } |
| if ((nbits = BN_num_bits(bitmap)) < 0) { |
| error("%s: bitmap bits < 0", __func__); |
| goto out; |
| } |
| for (serial = 0; serial < (u_int)nbits; serial++) { |
| if (serial > 0 && serial_lo + serial == 0) { |
| error("%s: bitmap wraps u64", __func__); |
| goto out; |
| } |
| if (!BN_is_bit_set(bitmap, serial)) |
| continue; |
| if (ssh_krl_revoke_cert_by_serial(krl, ca_key, |
| serial_lo + serial) != 0) { |
| error("%s: update failed", __func__); |
| goto out; |
| } |
| } |
| BN_free(bitmap); |
| bitmap = NULL; |
| break; |
| case KRL_SECTION_CERT_KEY_ID: |
| while (buffer_len(&subsect) > 0) { |
| if ((key_id = buffer_get_cstring_ret(&subsect, |
| NULL)) == NULL) { |
| error("%s: buffer error", __func__); |
| goto out; |
| } |
| if (ssh_krl_revoke_cert_by_key_id(krl, ca_key, |
| key_id) != 0) { |
| error("%s: update failed", __func__); |
| goto out; |
| } |
| free(key_id); |
| key_id = NULL; |
| } |
| break; |
| default: |
| error("Unsupported KRL certificate section %u", type); |
| goto out; |
| } |
| if (buffer_len(&subsect) > 0) { |
| error("KRL certificate section contains unparsed data"); |
| goto out; |
| } |
| } |
| |
| ret = 0; |
| out: |
| if (ca_key != NULL) |
| key_free(ca_key); |
| if (bitmap != NULL) |
| BN_free(bitmap); |
| free(key_id); |
| buffer_free(&subsect); |
| return ret; |
| } |
| |
| |
| /* Attempt to parse a KRL, checking its signature (if any) with sign_ca_keys. */ |
| int |
| ssh_krl_from_blob(Buffer *buf, struct ssh_krl **krlp, |
| const Key **sign_ca_keys, u_int nsign_ca_keys) |
| { |
| Buffer copy, sect; |
| struct ssh_krl *krl; |
| char timestamp[64]; |
| int ret = -1, r, sig_seen; |
| Key *key = NULL, **ca_used = NULL; |
| u_char type, *blob; |
| u_int i, j, sig_off, sects_off, blen, format_version, nca_used = 0; |
| |
| *krlp = NULL; |
| if (buffer_len(buf) < sizeof(KRL_MAGIC) - 1 || |
| memcmp(buffer_ptr(buf), KRL_MAGIC, sizeof(KRL_MAGIC) - 1) != 0) { |
| debug3("%s: not a KRL", __func__); |
| /* |
| * Return success but a NULL *krlp here to signal that the |
| * file might be a simple list of keys. |
| */ |
| return 0; |
| } |
| |
| /* Take a copy of the KRL buffer so we can verify its signature later */ |
| buffer_init(©); |
| buffer_append(©, buffer_ptr(buf), buffer_len(buf)); |
| |
| buffer_init(§); |
| buffer_consume(©, sizeof(KRL_MAGIC) - 1); |
| |
| if ((krl = ssh_krl_init()) == NULL) { |
| error("%s: alloc failed", __func__); |
| goto out; |
| } |
| |
| if (buffer_get_int_ret(&format_version, ©) != 0) { |
| error("%s: KRL truncated", __func__); |
| goto out; |
| } |
| if (format_version != KRL_FORMAT_VERSION) { |
| error("%s: KRL unsupported format version %u", |
| __func__, format_version); |
| goto out; |
| } |
| if (buffer_get_int64_ret(&krl->krl_version, ©) != 0 || |
| buffer_get_int64_ret(&krl->generated_date, ©) != 0 || |
| buffer_get_int64_ret(&krl->flags, ©) != 0 || |
| buffer_get_string_ptr_ret(©, NULL) == NULL || /* reserved */ |
| (krl->comment = buffer_get_cstring_ret(©, NULL)) == NULL) { |
| error("%s: buffer error", __func__); |
| goto out; |
| } |
| |
| format_timestamp(krl->generated_date, timestamp, sizeof(timestamp)); |
| debug("KRL version %llu generated at %s%s%s", krl->krl_version, |
| timestamp, *krl->comment ? ": " : "", krl->comment); |
| |
| /* |
| * 1st pass: verify signatures, if any. This is done to avoid |
| * detailed parsing of data whose provenance is unverified. |
| */ |
| sig_seen = 0; |
| sects_off = buffer_len(buf) - buffer_len(©); |
| while (buffer_len(©) > 0) { |
| if (buffer_get_char_ret(&type, ©) != 0 || |
| (blob = buffer_get_string_ptr_ret(©, &blen)) == NULL) { |
| error("%s: buffer error", __func__); |
| goto out; |
| } |
| debug3("%s: first pass, section 0x%02x", __func__, type); |
| if (type != KRL_SECTION_SIGNATURE) { |
| if (sig_seen) { |
| error("KRL contains non-signature section " |
| "after signature"); |
| goto out; |
| } |
| /* Not interested for now. */ |
| continue; |
| } |
| sig_seen = 1; |
| /* First string component is the signing key */ |
| if ((key = key_from_blob(blob, blen)) == NULL) { |
| error("%s: invalid signature key", __func__); |
| goto out; |
| } |
| sig_off = buffer_len(buf) - buffer_len(©); |
| /* Second string component is the signature itself */ |
| if ((blob = buffer_get_string_ptr_ret(©, &blen)) == NULL) { |
| error("%s: buffer error", __func__); |
| goto out; |
| } |
| /* Check signature over entire KRL up to this point */ |
| if (key_verify(key, blob, blen, |
| buffer_ptr(buf), buffer_len(buf) - sig_off) == -1) { |
| error("bad signaure on KRL"); |
| goto out; |
| } |
| /* Check if this key has already signed this KRL */ |
| for (i = 0; i < nca_used; i++) { |
| if (key_equal(ca_used[i], key)) { |
| error("KRL signed more than once with " |
| "the same key"); |
| goto out; |
| } |
| } |
| /* Record keys used to sign the KRL */ |
| xrealloc(ca_used, nca_used + 1, sizeof(*ca_used)); |
| ca_used[nca_used++] = key; |
| key = NULL; |
| break; |
| } |
| |
| /* |
| * 2nd pass: parse and load the KRL, skipping the header to the point |
| * where the section start. |
| */ |
| buffer_append(©, (u_char*)buffer_ptr(buf) + sects_off, |
| buffer_len(buf) - sects_off); |
| while (buffer_len(©) > 0) { |
| if (buffer_get_char_ret(&type, ©) != 0 || |
| (blob = buffer_get_string_ptr_ret(©, &blen)) == NULL) { |
| error("%s: buffer error", __func__); |
| goto out; |
| } |
| debug3("%s: second pass, section 0x%02x", __func__, type); |
| buffer_clear(§); |
| buffer_append(§, blob, blen); |
| |
| switch (type) { |
| case KRL_SECTION_CERTIFICATES: |
| if ((r = parse_revoked_certs(§, krl)) != 0) |
| goto out; |
| break; |
| case KRL_SECTION_EXPLICIT_KEY: |
| case KRL_SECTION_FINGERPRINT_SHA1: |
| while (buffer_len(§) > 0) { |
| if ((blob = buffer_get_string_ret(§, |
| &blen)) == NULL) { |
| error("%s: buffer error", __func__); |
| goto out; |
| } |
| if (type == KRL_SECTION_FINGERPRINT_SHA1 && |
| blen != 20) { |
| error("%s: bad SHA1 length", __func__); |
| goto out; |
| } |
| if (revoke_blob( |
| type == KRL_SECTION_EXPLICIT_KEY ? |
| &krl->revoked_keys : &krl->revoked_sha1s, |
| blob, blen) != 0) |
| goto out; /* revoke_blob frees blob */ |
| } |
| break; |
| case KRL_SECTION_SIGNATURE: |
| /* Handled above, but still need to stay in synch */ |
| buffer_clear(§); |
| if ((blob = buffer_get_string_ptr_ret(©, |
| &blen)) == NULL) { |
| error("%s: buffer error", __func__); |
| goto out; |
| } |
| break; |
| default: |
| error("Unsupported KRL section %u", type); |
| goto out; |
| } |
| if (buffer_len(§) > 0) { |
| error("KRL section contains unparsed data"); |
| goto out; |
| } |
| } |
| |
| /* Check that the key(s) used to sign the KRL weren't revoked */ |
| sig_seen = 0; |
| for (i = 0; i < nca_used; i++) { |
| if (ssh_krl_check_key(krl, ca_used[i]) == 0) |
| sig_seen = 1; |
| else { |
| key_free(ca_used[i]); |
| ca_used[i] = NULL; |
| } |
| } |
| if (nca_used && !sig_seen) { |
| error("All keys used to sign KRL were revoked"); |
| goto out; |
| } |
| |
| /* If we have CA keys, then verify that one was used to sign the KRL */ |
| if (sig_seen && nsign_ca_keys != 0) { |
| sig_seen = 0; |
| for (i = 0; !sig_seen && i < nsign_ca_keys; i++) { |
| for (j = 0; j < nca_used; j++) { |
| if (ca_used[j] == NULL) |
| continue; |
| if (key_equal(ca_used[j], sign_ca_keys[i])) { |
| sig_seen = 1; |
| break; |
| } |
| } |
| } |
| if (!sig_seen) { |
| error("KRL not signed with any trusted key"); |
| goto out; |
| } |
| } |
| |
| *krlp = krl; |
| ret = 0; |
| out: |
| if (ret != 0) |
| ssh_krl_free(krl); |
| for (i = 0; i < nca_used; i++) { |
| if (ca_used[i] != NULL) |
| key_free(ca_used[i]); |
| } |
| free(ca_used); |
| if (key != NULL) |
| key_free(key); |
| buffer_free(©); |
| buffer_free(§); |
| return ret; |
| } |
| |
| /* Checks whether a given key/cert is revoked. Does not check its CA */ |
| static int |
| is_key_revoked(struct ssh_krl *krl, const Key *key) |
| { |
| struct revoked_blob rb, *erb; |
| struct revoked_serial rs, *ers; |
| struct revoked_key_id rki, *erki; |
| struct revoked_certs *rc; |
| |
| /* Check explicitly revoked hashes first */ |
| bzero(&rb, sizeof(rb)); |
| if ((rb.blob = key_fingerprint_raw(key, SSH_FP_SHA1, &rb.len)) == NULL) |
| return -1; |
| erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha1s, &rb); |
| free(rb.blob); |
| if (erb != NULL) { |
| debug("%s: revoked by key SHA1", __func__); |
| return -1; |
| } |
| |
| /* Next, explicit keys */ |
| bzero(&rb, sizeof(rb)); |
| if (plain_key_blob(key, &rb.blob, &rb.len) != 0) |
| return -1; |
| erb = RB_FIND(revoked_blob_tree, &krl->revoked_keys, &rb); |
| free(rb.blob); |
| if (erb != NULL) { |
| debug("%s: revoked by explicit key", __func__); |
| return -1; |
| } |
| |
| if (!key_is_cert(key)) |
| return 0; |
| |
| /* Check cert revocation */ |
| if (revoked_certs_for_ca_key(krl, key->cert->signature_key, |
| &rc, 0) != 0) |
| return -1; |
| if (rc == NULL) |
| return 0; /* No entry for this CA */ |
| |
| /* Check revocation by cert key ID */ |
| bzero(&rki, sizeof(rki)); |
| rki.key_id = key->cert->key_id; |
| erki = RB_FIND(revoked_key_id_tree, &rc->revoked_key_ids, &rki); |
| if (erki != NULL) { |
| debug("%s: revoked by key ID", __func__); |
| return -1; |
| } |
| |
| /* Legacy cert formats lack serial numbers */ |
| if (key_cert_is_legacy(key)) |
| return 0; |
| |
| bzero(&rs, sizeof(rs)); |
| rs.lo = rs.hi = key->cert->serial; |
| ers = RB_FIND(revoked_serial_tree, &rc->revoked_serials, &rs); |
| if (ers != NULL) { |
| KRL_DBG(("%s: %llu matched %llu:%llu", __func__, |
| key->cert->serial, ers->lo, ers->hi)); |
| debug("%s: revoked by serial", __func__); |
| return -1; |
| } |
| KRL_DBG(("%s: %llu no match", __func__, key->cert->serial)); |
| |
| return 0; |
| } |
| |
| int |
| ssh_krl_check_key(struct ssh_krl *krl, const Key *key) |
| { |
| int r; |
| |
| debug2("%s: checking key", __func__); |
| if ((r = is_key_revoked(krl, key)) != 0) |
| return r; |
| if (key_is_cert(key)) { |
| debug2("%s: checking CA key", __func__); |
| if ((r = is_key_revoked(krl, key->cert->signature_key)) != 0) |
| return r; |
| } |
| debug3("%s: key okay", __func__); |
| return 0; |
| } |
| |
| /* Returns 0 on success, -1 on error or key revoked, -2 if path is not a KRL */ |
| int |
| ssh_krl_file_contains_key(const char *path, const Key *key) |
| { |
| Buffer krlbuf; |
| struct ssh_krl *krl; |
| int revoked, fd; |
| |
| if (path == NULL) |
| return 0; |
| |
| if ((fd = open(path, O_RDONLY)) == -1) { |
| error("open %s: %s", path, strerror(errno)); |
| error("Revoked keys file not accessible - refusing public key " |
| "authentication"); |
| return -1; |
| } |
| buffer_init(&krlbuf); |
| if (!key_load_file(fd, path, &krlbuf)) { |
| close(fd); |
| buffer_free(&krlbuf); |
| error("Revoked keys file not readable - refusing public key " |
| "authentication"); |
| return -1; |
| } |
| close(fd); |
| if (ssh_krl_from_blob(&krlbuf, &krl, NULL, 0) != 0) { |
| buffer_free(&krlbuf); |
| error("Invalid KRL, refusing public key " |
| "authentication"); |
| return -1; |
| } |
| buffer_free(&krlbuf); |
| if (krl == NULL) { |
| debug3("%s: %s is not a KRL file", __func__, path); |
| return -2; |
| } |
| debug2("%s: checking KRL %s", __func__, path); |
| revoked = ssh_krl_check_key(krl, key) != 0; |
| ssh_krl_free(krl); |
| return revoked ? -1 : 0; |
| } |