diff options
author | Damien Miller <djm@mindrot.org> | 2013-01-18 11:44:04 +1100 |
---|---|---|
committer | Damien Miller <djm@mindrot.org> | 2013-01-18 11:44:04 +1100 |
commit | f3747bf4014a450c9aaf1d88b010f6e579d10072 (patch) | |
tree | 0b1e1b497da13eb815e16a0f43be09e873e6a243 | |
parent | b26699bbadaffa1b1de2f6b0e175b77aba337de5 (diff) |
- djm@cvs.openbsd.org 2013/01/17 23:00:01
[auth.c key.c key.h ssh-keygen.1 ssh-keygen.c sshd_config.5]
[krl.c krl.h PROTOCOL.krl]
add support for Key Revocation Lists (KRLs). These are a compact way to
represent lists of revoked keys and certificates, taking as little as
a single bit of incremental cost to revoke a certificate by serial number.
KRLs are loaded via the existing RevokedKeys sshd_config option.
feedback and ok markus@
-rw-r--r-- | ChangeLog | 11 | ||||
-rw-r--r-- | Makefile.in | 4 | ||||
-rw-r--r-- | PROTOCOL.krl | 164 | ||||
-rw-r--r-- | auth.c | 15 | ||||
-rw-r--r-- | key.c | 40 | ||||
-rw-r--r-- | key.h | 6 | ||||
-rw-r--r-- | krl.c | 1227 | ||||
-rw-r--r-- | krl.h | 63 | ||||
-rw-r--r-- | ssh-keygen.1 | 118 | ||||
-rw-r--r-- | ssh-keygen.c | 257 | ||||
-rw-r--r-- | sshd_config.5 | 13 |
11 files changed, 1884 insertions, 34 deletions
@@ -1,3 +1,14 @@ +20130118 + - (djm) OpenBSD CVS Sync + - djm@cvs.openbsd.org 2013/01/17 23:00:01 + [auth.c key.c key.h ssh-keygen.1 ssh-keygen.c sshd_config.5] + [krl.c krl.h PROTOCOL.krl] + add support for Key Revocation Lists (KRLs). These are a compact way to + represent lists of revoked keys and certificates, taking as little as + a single bit of incremental cost to revoke a certificate by serial number. + KRLs are loaded via the existing RevokedKeys sshd_config option. + feedback and ok markus@ + 20130117 - (djm) [regress/cipher-speed.sh regress/integrity.sh regress/try-ciphers.sh] check for GCM support before testing GCM ciphers. diff --git a/Makefile.in b/Makefile.in index 8765b7ef..74eeab57 100644 --- a/Makefile.in +++ b/Makefile.in @@ -1,4 +1,4 @@ -# $Id: Makefile.in,v 1.329 2012/12/17 04:59:43 dtucker Exp $ +# $Id: Makefile.in,v 1.330 2013/01/18 00:44:04 djm Exp $ # uncomment if you run a non bourne compatable shell. Ie. csh #SHELL = @SH@ @@ -71,7 +71,7 @@ LIBSSH_OBJS=acss.o authfd.o authfile.o bufaux.o bufbn.o buffer.o \ monitor_fdpass.o rijndael.o ssh-dss.o ssh-ecdsa.o ssh-rsa.o dh.o \ kexdh.o kexgex.o kexdhc.o kexgexc.o bufec.o kexecdh.o kexecdhc.o \ msg.o progressmeter.o dns.o entropy.o gss-genr.o umac.o umac128.o \ - jpake.o schnorr.o ssh-pkcs11.o + jpake.o schnorr.o ssh-pkcs11.o krl.o SSHOBJS= ssh.o readconf.o clientloop.o sshtty.o \ sshconnect.o sshconnect1.o sshconnect2.o mux.o \ diff --git a/PROTOCOL.krl b/PROTOCOL.krl new file mode 100644 index 00000000..e8caa452 --- /dev/null +++ b/PROTOCOL.krl @@ -0,0 +1,164 @@ +This describes the key/certificate revocation list format for OpenSSH. + +1. Overall format + +The KRL consists of a header and zero or more sections. The header is: + +#define KRL_MAGIC 0x5353484b524c0a00ULL /* "SSHKRL\n\0" */ +#define KRL_FORMAT_VERSION 1 + + uint64 KRL_MAGIC + uint32 KRL_FORMAT_VERSION + uint64 krl_version + uint64 generated_date + uint64 flags + string reserved + string comment + +Where "krl_version" is a version number that increases each time the KRL +is modified, "generated_date" is the time in seconds since 1970-01-01 +00:00:00 UTC that the KRL was generated, "comment" is an optional comment +and "reserved" an extension field whose contents are currently ignored. +No "flags" are currently defined. + +Following the header are zero or more sections, each consisting of: + + byte section_type + string section_data + +Where "section_type" indicates the type of the "section_data". An exception +to this is the KRL_SECTION_SIGNATURE section, that has a slightly different +format (see below). + +The available section types are: + +#define KRL_SECTION_CERTIFICATES 1 +#define KRL_SECTION_EXPLICIT_KEY 2 +#define KRL_SECTION_FINGERPRINT_SHA1 3 +#define KRL_SECTION_SIGNATURE 4 + +3. Certificate serial section + +These sections use type KRL_SECTION_CERTIFICATES to revoke certificates by +serial number or key ID. The consist of the CA key that issued the +certificates to be revoked and a reserved field whose contents is currently +ignored. + + string ca_key + string reserved + +Followed by one or more sections: + + byte cert_section_type + string cert_section_data + +The certificate section types are: + +#define KRL_SECTION_CERT_SERIAL_LIST 0x20 +#define KRL_SECTION_CERT_SERIAL_RANGE 0x21 +#define KRL_SECTION_CERT_SERIAL_BITMAP 0x22 +#define KRL_SECTION_CERT_KEY_ID 0x23 + +2.1 Certificate serial list section + +This section is identified as KRL_SECTION_CERT_SERIAL_LIST. It revokes +certificates by listing their serial numbers. The cert_section_data in this +case contains: + + uint64 revoked_cert_serial + uint64 ... + +This section may appear multiple times. + +2.2. Certificate serial range section + +These sections use type KRL_SECTION_CERT_SERIAL_RANGE and hold +a range of serial numbers of certificates: + + uint64 serial_min + uint64 serial_max + +All certificates in the range serial_min <= serial <= serial_max are +revoked. + +This section may appear multiple times. + +2.3. Certificate serial bitmap section + +Bitmap sections use type KRL_SECTION_CERT_SERIAL_BITMAP and revoke keys +by listing their serial number in a bitmap. + + uint64 serial_offset + mpint revoked_keys_bitmap + +A bit set at index N in the bitmap corresponds to revocation of a keys with +serial number (serial_offset + N). + +This section may appear multiple times. + +2.4. Revoked key ID sections + +KRL_SECTION_CERT_KEY_ID sections revoke particular certificate "key +ID" strings. This may be useful in revoking all certificates +associated with a particular identity, e.g. a host or a user. + + string key_id[0] + ... + +This section must contain at least one "key_id". This section may appear +multiple times. + +3. Explicit key sections + +These sections, identified as KRL_SECTION_EXPLICIT_KEY, revoke keys +(not certificates). They are less space efficient than serial numbers, +but are able to revoke plain keys. + + string public_key_blob[0] + .... + +This section must contain at least one "public_key_blob". The blob +must be a raw key (i.e. not a certificate). + +This section may appear multiple times. + +4. SHA1 fingerprint sections + +These sections, identified as KRL_SECTION_FINGERPRINT_SHA1, revoke +plain keys (i.e. not certificates) by listing their SHA1 hashes: + + string public_key_hash[0] + .... + +This section must contain at least one "public_key_hash". The hash blob +is obtained by taking the SHA1 hash of the public key blob. Hashes in +this section must appear in numeric order, treating each hash as a big- +endian integer. + +This section may appear multiple times. + +5. KRL signature sections + +The KRL_SECTION_SIGNATURE section serves a different purpose to the +preceeding ones: to provide cryptographic authentication of a KRL that +is retrieved over a channel that does not provide integrity protection. +Its format is slightly different to the previously-described sections: +in order to simplify the signature generation, it includes as a "body" +two string components instead of one. + + byte KRL_SECTION_SIGNATURE + string signature_key + string signature + +The signature is calculated over the entire KRL from the KRL_MAGIC +to this subsection's "signature_key", including both and using the +signature generation rules appropriate for the type of "signature_key". + +This section must appear last in the KRL. If multiple signature sections +appear, they must appear consecutively at the end of the KRL file. + +Implementations that retrieve KRLs over untrusted channels must verify +signatures. Signature sections are optional for KRLs distributed by +trusted means. + +$OpenBSD: PROTOCOL.krl,v 1.2 2013/01/18 00:24:58 djm Exp $ @@ -1,4 +1,4 @@ -/* $OpenBSD: auth.c,v 1.99 2012/12/14 05:26:43 dtucker Exp $ */ +/* $OpenBSD: auth.c,v 1.100 2013/01/17 23:00:01 djm Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. * @@ -71,6 +71,7 @@ #endif #include "authfile.h" #include "monitor_wrap.h" +#include "krl.h" /* import */ extern ServerOptions options; @@ -640,7 +641,16 @@ auth_key_is_revoked(Key *key) if (options.revoked_keys_file == NULL) return 0; - + switch (ssh_krl_file_contains_key(options.revoked_keys_file, key)) { + case 0: + return 0; /* Not revoked */ + case -2: + break; /* Not a KRL */ + default: + goto revoked; + } + debug3("%s: treating %s as a key list", __func__, + options.revoked_keys_file); switch (key_in_file(key, options.revoked_keys_file, 0)) { case 0: /* key not revoked */ @@ -651,6 +661,7 @@ auth_key_is_revoked(Key *key) "authentication"); return 1; case 1: + revoked: /* Key revoked */ key_fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); error("WARNING: authentication attempt with a revoked " @@ -1,4 +1,4 @@ -/* $OpenBSD: key.c,v 1.99 2012/05/23 03:28:28 djm Exp $ */ +/* $OpenBSD: key.c,v 1.100 2013/01/17 23:00:01 djm Exp $ */ /* * read_bignum(): * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -55,6 +55,8 @@ #include "misc.h" #include "ssh2.h" +static int to_blob(const Key *, u_char **, u_int *, int); + static struct KeyCert * cert_new(void) { @@ -324,14 +326,15 @@ key_equal(const Key *a, const Key *b) } u_char* -key_fingerprint_raw(Key *k, enum fp_type dgst_type, u_int *dgst_raw_length) +key_fingerprint_raw(const Key *k, enum fp_type dgst_type, + u_int *dgst_raw_length) { const EVP_MD *md = NULL; EVP_MD_CTX ctx; u_char *blob = NULL; u_char *retval = NULL; u_int len = 0; - int nlen, elen, otype; + int nlen, elen; *dgst_raw_length = 0; @@ -371,10 +374,7 @@ key_fingerprint_raw(Key *k, enum fp_type dgst_type, u_int *dgst_raw_length) case KEY_ECDSA_CERT: case KEY_RSA_CERT: /* We want a fingerprint of the _key_ not of the cert */ - otype = k->type; - k->type = key_type_plain(k->type); - key_to_blob(k, &blob, &len); - k->type = otype; + to_blob(k, &blob, &len, 1); break; case KEY_UNSPEC: return retval; @@ -1587,18 +1587,19 @@ key_from_blob(const u_char *blob, u_int blen) return key; } -int -key_to_blob(const Key *key, u_char **blobp, u_int *lenp) +static int +to_blob(const Key *key, u_char **blobp, u_int *lenp, int force_plain) { Buffer b; - int len; + int len, type; if (key == NULL) { error("key_to_blob: key == NULL"); return 0; } buffer_init(&b); - switch (key->type) { + type = force_plain ? key_type_plain(key->type) : key->type; + switch (type) { case KEY_DSA_CERT_V00: case KEY_RSA_CERT_V00: case KEY_DSA_CERT: @@ -1609,7 +1610,8 @@ key_to_blob(const Key *key, u_char **blobp, u_int *lenp) buffer_len(&key->cert->certblob)); break; case KEY_DSA: - buffer_put_cstring(&b, key_ssh_name(key)); + buffer_put_cstring(&b, + key_ssh_name_from_type_nid(type, key->ecdsa_nid)); buffer_put_bignum2(&b, key->dsa->p); buffer_put_bignum2(&b, key->dsa->q); buffer_put_bignum2(&b, key->dsa->g); @@ -1617,14 +1619,16 @@ key_to_blob(const Key *key, u_char **blobp, u_int *lenp) break; #ifdef OPENSSL_HAS_ECC case KEY_ECDSA: - buffer_put_cstring(&b, key_ssh_name(key)); + buffer_put_cstring(&b, + key_ssh_name_from_type_nid(type, key->ecdsa_nid)); buffer_put_cstring(&b, key_curve_nid_to_name(key->ecdsa_nid)); buffer_put_ecpoint(&b, EC_KEY_get0_group(key->ecdsa), EC_KEY_get0_public_key(key->ecdsa)); break; #endif case KEY_RSA: - buffer_put_cstring(&b, key_ssh_name(key)); + buffer_put_cstring(&b, + key_ssh_name_from_type_nid(type, key->ecdsa_nid)); buffer_put_bignum2(&b, key->rsa->e); buffer_put_bignum2(&b, key->rsa->n); break; @@ -1646,6 +1650,12 @@ key_to_blob(const Key *key, u_char **blobp, u_int *lenp) } int +key_to_blob(const Key *key, u_char **blobp, u_int *lenp) +{ + return to_blob(key, blobp, lenp, 0); +} + +int key_sign( const Key *key, u_char **sigp, u_int *lenp, @@ -2024,7 +2034,7 @@ key_cert_check_authority(const Key *k, int want_host, int require_principal, } int -key_cert_is_legacy(Key *k) +key_cert_is_legacy(const Key *k) { switch (k->type) { case KEY_DSA_CERT_V00: @@ -1,4 +1,4 @@ -/* $OpenBSD: key.h,v 1.34 2012/05/23 03:28:28 djm Exp $ */ +/* $OpenBSD: key.h,v 1.35 2013/01/17 23:00:01 djm Exp $ */ /* * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. @@ -96,7 +96,7 @@ Key *key_demote(const Key *); int key_equal_public(const Key *, const Key *); int key_equal(const Key *, const Key *); char *key_fingerprint(Key *, enum fp_type, enum fp_rep); -u_char *key_fingerprint_raw(Key *, enum fp_type, u_int *); +u_char *key_fingerprint_raw(const Key *, enum fp_type, u_int *); const char *key_type(const Key *); const char *key_cert_type(const Key *); int key_write(const Key *, FILE *); @@ -114,7 +114,7 @@ int key_certify(Key *, Key *); void key_cert_copy(const Key *, struct Key *); int key_cert_check_authority(const Key *, int, int, const char *, const char **); -int key_cert_is_legacy(Key *); +int key_cert_is_legacy(const Key *); int key_ecdsa_nid_from_name(const char *); int key_curve_name_to_nid(const char *); @@ -0,0 +1,1227 @@ +/* + * 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 1.2 2013/01/18 00:24:58 djm Exp $ */ + +#include "includes.h" + +#include <sys/types.h> +#include <sys/param.h> +#include <sys/tree.h> +#include <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(ers); + 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(&se |