From a98339edbc1fc21342a390f345179a9c3031bef7 Mon Sep 17 00:00:00 2001 From: "djm@openbsd.org" Date: Wed, 28 Jun 2017 01:09:22 +0000 Subject: upstream commit Allow ssh-keygen to use a key held in ssh-agent as a CA when signing certificates. bz#2377 ok markus Upstream-ID: fb42e920b592edcbb5b50465739a867c09329c8f --- ssh-keygen.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 67 insertions(+), 9 deletions(-) (limited to 'ssh-keygen.c') diff --git a/ssh-keygen.c b/ssh-keygen.c index cc3a7df18..b6b690051 100644 --- a/ssh-keygen.c +++ b/ssh-keygen.c @@ -1,4 +1,4 @@ -/* $OpenBSD: ssh-keygen.c,v 1.304 2017/05/30 14:16:41 markus Exp $ */ +/* $OpenBSD: ssh-keygen.c,v 1.305 2017/06/28 01:09:22 djm Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1994 Tatu Ylonen , Espoo, Finland @@ -59,6 +59,7 @@ #include "krl.h" #include "digest.h" #include "utf8.h" +#include "authfd.h" #ifdef WITH_OPENSSL # define DEFAULT_KEY_TYPE_NAME "rsa" @@ -121,6 +122,9 @@ char *identity_comment = NULL; /* Path to CA key when certifying keys. */ char *ca_key_path = NULL; +/* Prefer to use agent keys for CA signing */ +int prefer_agent = 0; + /* Certificate serial number */ unsigned long long cert_serial = 0; @@ -1597,24 +1601,66 @@ load_pkcs11_key(char *path) #endif /* ENABLE_PKCS11 */ } +/* Signer for sshkey_certify_custom that uses the agent */ +static int +agent_signer(const struct sshkey *key, u_char **sigp, size_t *lenp, + const u_char *data, size_t datalen, + const char *alg, u_int compat, void *ctx) +{ + int *agent_fdp = (int *)ctx; + + return ssh_agent_sign(*agent_fdp, key, sigp, lenp, + data, datalen, alg, compat); +} + static void do_ca_sign(struct passwd *pw, int argc, char **argv) { - int r, i, fd; + int r, i, fd, found, agent_fd = -1; u_int n; struct sshkey *ca, *public; char valid[64], *otmp, *tmp, *cp, *out, *comment, **plist = NULL; FILE *f; + struct ssh_identitylist *agent_ids; + size_t j; #ifdef ENABLE_PKCS11 pkcs11_init(1); #endif tmp = tilde_expand_filename(ca_key_path, pw->pw_uid); if (pkcs11provider != NULL) { + /* If a PKCS#11 token was specified then try to use it */ if ((ca = load_pkcs11_key(tmp)) == NULL) fatal("No PKCS#11 key matching %s found", ca_key_path); - } else + } else if (prefer_agent) { + /* + * Agent signature requested. Try to use agent after making + * sure the public key specified is actually present in the + * agent. + */ + if ((r = sshkey_load_public(tmp, &ca, NULL)) != 0) + fatal("Cannot load CA public key %s: %s", + tmp, ssh_err(r)); + if ((r = ssh_get_authentication_socket(&agent_fd)) != 0) + fatal("Cannot use public key for CA signature: %s", + ssh_err(r)); + if ((r = ssh_fetch_identitylist(agent_fd, &agent_ids)) != 0) + fatal("Retrieve agent key list: %s", ssh_err(r)); + found = 0; + for (j = 0; j < agent_ids->nkeys; j++) { + if (sshkey_equal(ca, agent_ids->keys[j])) { + found = 1; + break; + } + } + if (!found) + fatal("CA key %s not found in agent", tmp); + ssh_free_identitylist(agent_ids); + ca->flags |= SSHKEY_FLAG_EXT; + } else { + /* CA key is assumed to be a private key on the filesystem */ ca = load_identity(tmp); + } free(tmp); if (key_type_name != NULL && @@ -1664,8 +1710,16 @@ do_ca_sign(struct passwd *pw, int argc, char **argv) &public->cert->signature_key)) != 0) fatal("sshkey_from_private (ca key): %s", ssh_err(r)); - if ((r = sshkey_certify(public, ca, key_type_name)) != 0) - fatal("Couldn't certify key %s: %s", tmp, ssh_err(r)); + if (agent_fd != -1 && (ca->flags & SSHKEY_FLAG_EXT) != 0) { + if ((r = sshkey_certify_custom(public, ca, + key_type_name, agent_signer, &agent_fd)) != 0) + fatal("Couldn't certify key %s via agent: %s", + tmp, ssh_err(r)); + } else { + if ((sshkey_certify(public, ca, key_type_name)) != 0) + fatal("Couldn't certify key %s: %s", + tmp, ssh_err(r)); + } if ((cp = strrchr(tmp, '.')) != NULL && strcmp(cp, ".pub") == 0) *cp = '\0'; @@ -2261,8 +2315,9 @@ usage(void) " ssh-keygen -T output_file -f input_file [-v] [-a rounds] [-J num_lines]\n" " [-j start_line] [-K checkpt] [-W generator]\n" #endif - " ssh-keygen -s ca_key -I certificate_identity [-h] [-n principals]\n" - " [-O option] [-V validity_interval] [-z serial_number] file ...\n" + " ssh-keygen -s ca_key -I certificate_identity [-h] [-U]\n" + " [-D pkcs11_provider] [-n principals] [-O option]\n" + " [-V validity_interval] [-z serial_number] file ...\n" " ssh-keygen -L [-f input_keyfile]\n" " ssh-keygen -A\n" " ssh-keygen -k -f krl_file [-u] [-s ca_public] [-z version_number]\n" @@ -2320,8 +2375,8 @@ main(int argc, char **argv) if (gethostname(hostname, sizeof(hostname)) < 0) fatal("gethostname: %s", strerror(errno)); - /* Remaining characters: UYdw */ - while ((opt = getopt(argc, argv, "ABHLQXceghiklopquvxy" + /* Remaining characters: Ydw */ + while ((opt = getopt(argc, argv, "ABHLQUXceghiklopquvxy" "C:D:E:F:G:I:J:K:M:N:O:P:R:S:T:V:W:Z:" "a:b:f:g:j:m:n:r:s:t:z:")) != -1) { switch (opt) { @@ -2448,6 +2503,9 @@ main(int argc, char **argv) case 'D': pkcs11provider = optarg; break; + case 'U': + prefer_agent = 1; + break; case 'u': update_krl = 1; break; -- cgit v1.2.3