X-Git-Url: http://andersk.mit.edu/gitweb/gssapi-openssh.git/blobdiff_plain/df84fde0895c2402636cb9224f3539771aab86cd..06816bdd4f3738c71a6bc698a1a487ef0c91efcc:/openssh/ssh-agent.c diff --git a/openssh/ssh-agent.c b/openssh/ssh-agent.c index 53bf051..dd7e22a 100644 --- a/openssh/ssh-agent.c +++ b/openssh/ssh-agent.c @@ -34,8 +34,8 @@ */ #include "includes.h" -#include "openbsd-compat/fake-queue.h" -RCSID("$OpenBSD: ssh-agent.c,v 1.95 2002/06/19 00:27:55 deraadt Exp $"); +#include "openbsd-compat/sys-queue.h" +RCSID("$OpenBSD: ssh-agent.c,v 1.122 2004/10/29 22:53:56 djm Exp $"); #include #include @@ -50,11 +50,16 @@ RCSID("$OpenBSD: ssh-agent.c,v 1.95 2002/06/19 00:27:55 deraadt Exp $"); #include "authfd.h" #include "compat.h" #include "log.h" +#include "misc.h" #ifdef SMARTCARD #include "scard.h" #endif +#if defined(HAVE_SYS_PRCTL_H) +#include /* For prctl() and PR_SET_DUMPABLE */ +#endif + typedef enum { AUTH_UNUSED, AUTH_SOCKET, @@ -77,6 +82,7 @@ typedef struct identity { Key *key; char *comment; u_int death; + u_int confirm; } Identity; typedef struct { @@ -100,16 +106,27 @@ char socket_dir[1024]; int locked = 0; char *lock_passwd = NULL; -#ifdef HAVE___PROGNAME extern char *__progname; -#else -char *__progname; -#endif + +/* Default lifetime (0 == forever) */ +static int lifetime = 0; + +static void +close_socket(SocketEntry *e) +{ + close(e->fd); + e->fd = -1; + e->type = AUTH_UNUSED; + buffer_free(&e->input); + buffer_free(&e->output); + buffer_free(&e->request); +} static void idtab_init(void) { int i; + for (i = 0; i <=2; i++) { TAILQ_INIT(&idtable[i].idlist); idtable[i].nentries = 0; @@ -147,13 +164,29 @@ lookup_identity(Key *key, int version) return (NULL); } +/* Check confirmation of keysign request */ +static int +confirm_key(Identity *id) +{ + char *p; + int ret = -1; + + p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); + if (ask_permission("Allow use of key %s?\nKey fingerprint %s.", + id->comment, p)) + ret = 0; + xfree(p); + + return (ret); +} + /* send list of supported public keys to 'client' */ static void process_request_identities(SocketEntry *e, int version) { Idtab *tab = idtab_lookup(version); - Buffer msg; Identity *id; + Buffer msg; buffer_init(&msg); buffer_put_char(&msg, (version == 1) ? @@ -182,21 +215,21 @@ process_request_identities(SocketEntry *e, int version) static void process_authentication_challenge1(SocketEntry *e) { - Identity *id; - Key *key; + u_char buf[32], mdbuf[16], session_id[16]; + u_int response_type; BIGNUM *challenge; + Identity *id; int i, len; Buffer msg; MD5_CTX md; - u_char buf[32], mdbuf[16], session_id[16]; - u_int response_type; + Key *key; buffer_init(&msg); key = key_new(KEY_RSA1); if ((challenge = BN_new()) == NULL) fatal("process_authentication_challenge1: BN_new failed"); - buffer_get_int(&e->request); /* ignored */ + (void) buffer_get_int(&e->request); /* ignored */ buffer_get_bignum(&e->request, key->rsa->e); buffer_get_bignum(&e->request, key->rsa->n); buffer_get_bignum(&e->request, challenge); @@ -210,7 +243,7 @@ process_authentication_challenge1(SocketEntry *e) goto failure; id = lookup_identity(key, 1); - if (id != NULL) { + if (id != NULL && (!id->confirm || confirm_key(id) == 0)) { Key *private = id->key; /* Decrypt the challenge using the private key. */ if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) @@ -219,7 +252,7 @@ process_authentication_challenge1(SocketEntry *e) /* The response is MD5 of decrypted challenge plus session id. */ len = BN_num_bytes(challenge); if (len <= 0 || len > 32) { - log("process_authentication_challenge: bad challenge length %d", len); + logit("process_authentication_challenge: bad challenge length %d", len); goto failure; } memset(buf, 0, 32); @@ -251,13 +284,12 @@ send: static void process_sign_request2(SocketEntry *e) { - extern int datafellows; - Key *key; u_char *blob, *data, *signature = NULL; u_int blen, dlen, slen = 0; - int flags; + extern int datafellows; + int ok = -1, flags; Buffer msg; - int ok = -1; + Key *key; datafellows = 0; @@ -271,7 +303,7 @@ process_sign_request2(SocketEntry *e) key = key_from_blob(blob, blen); if (key != NULL) { Identity *id = lookup_identity(key, 2); - if (id != NULL) + if (id != NULL && (!id->confirm || confirm_key(id) == 0)) ok = key_sign(id->key, &signature, &slen, data, dlen); } key_free(key); @@ -296,11 +328,10 @@ process_sign_request2(SocketEntry *e) static void process_remove_identity(SocketEntry *e, int version) { + u_int blen, bits; + int success = 0; Key *key = NULL; u_char *blob; - u_int blen; - u_int bits; - int success = 0; switch (version) { case 1: @@ -310,7 +341,7 @@ process_remove_identity(SocketEntry *e, int version) buffer_get_bignum(&e->request, key->rsa->n); if (bits != key_size(key)) - log("Warning: identity keysize mismatch: actual %d, announced %d", + logit("Warning: identity keysize mismatch: actual %u, announced %u", key_size(key), bits); break; case 2: @@ -370,10 +401,10 @@ process_remove_all_identities(SocketEntry *e, int version) static void reaper(void) { - Idtab *tab; + u_int now = time(NULL); Identity *id, *nxt; int version; - u_int now = time(NULL); + Idtab *tab; for (version = 1; version < 3; version++) { tab = idtab_lookup(version); @@ -391,16 +422,15 @@ reaper(void) static void process_add_identity(SocketEntry *e, int version) { - Key *k = NULL; - char *type_name; - char *comment; - int type, success = 0, death = 0; Idtab *tab = idtab_lookup(version); + int type, success = 0, death = 0, confirm = 0; + char *type_name, *comment; + Key *k = NULL; switch (version) { case 1: k = key_new_private(KEY_RSA1); - buffer_get_int(&e->request); /* ignored */ + (void) buffer_get_int(&e->request); /* ignored */ buffer_get_bignum(&e->request, k->rsa->n); buffer_get_bignum(&e->request, k->rsa->e); buffer_get_bignum(&e->request, k->rsa->d); @@ -444,6 +474,17 @@ process_add_identity(SocketEntry *e, int version) } break; } + /* enable blinding */ + switch (k->type) { + case KEY_RSA: + case KEY_RSA1: + if (RSA_blinding_on(k->rsa, NULL) != 1) { + error("process_add_identity: RSA_blinding_on failed"); + key_free(k); + goto send; + } + break; + } comment = buffer_get_string(&e->request, NULL); if (k == NULL) { xfree(comment); @@ -455,15 +496,21 @@ process_add_identity(SocketEntry *e, int version) case SSH_AGENT_CONSTRAIN_LIFETIME: death = time(NULL) + buffer_get_int(&e->request); break; + case SSH_AGENT_CONSTRAIN_CONFIRM: + confirm = 1; + break; default: break; } } + if (lifetime && !death) + death = time(NULL) + lifetime; if (lookup_identity(k, version) == NULL) { Identity *id = xmalloc(sizeof(Identity)); id->key = k; id->comment = comment; id->death = death; + id->confirm = confirm; TAILQ_INSERT_TAIL(&tab->idlist, id, next); /* Increment the number of identities. */ tab->nentries++; @@ -481,8 +528,8 @@ send: static void process_lock_agent(SocketEntry *e, int lock) { - char *passwd; int success = 0; + char *passwd; passwd = buffer_get_string(&e->request, NULL); if (locked && !lock && strcmp(passwd, lock_passwd) == 0) { @@ -523,14 +570,30 @@ no_identities(SocketEntry *e, u_int type) static void process_add_smartcard_key (SocketEntry *e) { + char *sc_reader_id = NULL, *pin; + int i, version, success = 0, death = 0, confirm = 0; + Key **keys, *k; Identity *id; Idtab *tab; - Key **keys, *k; - char *sc_reader_id = NULL, *pin; - int i, version, success = 0; sc_reader_id = buffer_get_string(&e->request, NULL); pin = buffer_get_string(&e->request, NULL); + + while (buffer_len(&e->request)) { + switch (buffer_get_char(&e->request)) { + case SSH_AGENT_CONSTRAIN_LIFETIME: + death = time(NULL) + buffer_get_int(&e->request); + break; + case SSH_AGENT_CONSTRAIN_CONFIRM: + confirm = 1; + break; + default: + break; + } + } + if (lifetime && !death) + death = time(NULL) + lifetime; + keys = sc_get_keys(sc_reader_id, pin); xfree(sc_reader_id); xfree(pin); @@ -546,8 +609,9 @@ process_add_smartcard_key (SocketEntry *e) if (lookup_identity(k, version) == NULL) { id = xmalloc(sizeof(Identity)); id->key = k; - id->comment = xstrdup("smartcard key"); - id->death = 0; + id->comment = sc_get_key_label(k); + id->death = death; + id->confirm = confirm; TAILQ_INSERT_TAIL(&tab->idlist, id, next); tab->nentries++; success = 1; @@ -566,11 +630,11 @@ send: static void process_remove_smartcard_key(SocketEntry *e) { - Identity *id; - Idtab *tab; - Key **keys, *k = NULL; char *sc_reader_id = NULL, *pin; int i, version, success = 0; + Key **keys, *k = NULL; + Identity *id; + Idtab *tab; sc_reader_id = buffer_get_string(&e->request, NULL); pin = buffer_get_string(&e->request, NULL); @@ -608,8 +672,7 @@ send: static void process_message(SocketEntry *e) { - u_int msg_len; - u_int type; + u_int msg_len, type; u_char *cp; /* kill dead keys */ @@ -620,12 +683,7 @@ process_message(SocketEntry *e) cp = buffer_ptr(&e->input); msg_len = GET_32BIT(cp); if (msg_len > 256 * 1024) { - shutdown(e->fd, SHUT_RDWR); - close(e->fd); - e->type = AUTH_UNUSED; - buffer_free(&e->input); - buffer_free(&e->output); - buffer_free(&e->request); + close_socket(e); return; } if (buffer_len(&e->input) < msg_len + 4) @@ -697,6 +755,7 @@ process_message(SocketEntry *e) break; #ifdef SMARTCARD case SSH_AGENTC_ADD_SMARTCARD_KEY: + case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED: process_add_smartcard_key(e); break; case SSH_AGENTC_REMOVE_SMARTCARD_KEY: @@ -716,9 +775,9 @@ process_message(SocketEntry *e) static void new_socket(sock_type type, int fd) { - u_int i, old_alloc; - if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) - error("fcntl O_NONBLOCK: %s", strerror(errno)); + u_int i, old_alloc, new_alloc; + + set_nonblock(fd); if (fd > max_fd) max_fd = fd; @@ -726,29 +785,30 @@ new_socket(sock_type type, int fd) for (i = 0; i < sockets_alloc; i++) if (sockets[i].type == AUTH_UNUSED) { sockets[i].fd = fd; - sockets[i].type = type; buffer_init(&sockets[i].input); buffer_init(&sockets[i].output); buffer_init(&sockets[i].request); + sockets[i].type = type; return; } old_alloc = sockets_alloc; - sockets_alloc += 10; + new_alloc = sockets_alloc + 10; if (sockets) - sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0])); + sockets = xrealloc(sockets, new_alloc * sizeof(sockets[0])); else - sockets = xmalloc(sockets_alloc * sizeof(sockets[0])); - for (i = old_alloc; i < sockets_alloc; i++) + sockets = xmalloc(new_alloc * sizeof(sockets[0])); + for (i = old_alloc; i < new_alloc; i++) sockets[i].type = AUTH_UNUSED; - sockets[old_alloc].type = type; + sockets_alloc = new_alloc; sockets[old_alloc].fd = fd; buffer_init(&sockets[old_alloc].input); buffer_init(&sockets[old_alloc].output); buffer_init(&sockets[old_alloc].request); + sockets[old_alloc].type = type; } static int -prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp) +prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp) { u_int i, sz; int n = 0; @@ -801,11 +861,13 @@ prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp) static void after_select(fd_set *readset, fd_set *writeset) { - u_int i; - int len, sock; + struct sockaddr_un sunaddr; socklen_t slen; char buf[1024]; - struct sockaddr_un sunaddr; + int len, sock; + u_int i; + uid_t euid; + gid_t egid; for (i = 0; i < sockets_alloc; i++) switch (sockets[i].type) { @@ -821,6 +883,19 @@ after_select(fd_set *readset, fd_set *writeset) strerror(errno)); break; } + if (getpeereid(sock, &euid, &egid) < 0) { + error("getpeereid %d failed: %s", + sock, strerror(errno)); + close(sock); + break; + } + if ((euid != 0) && (getuid() != euid)) { + error("uid mismatch: " + "peer euid %u != uid %u", + (u_int) euid, (u_int) getuid()); + close(sock); + break; + } new_socket(AUTH_CONNECTION, sock); } break; @@ -837,12 +912,7 @@ after_select(fd_set *readset, fd_set *writeset) break; } while (1); if (len <= 0) { - shutdown(sockets[i].fd, SHUT_RDWR); - close(sockets[i].fd); - sockets[i].type = AUTH_UNUSED; - buffer_free(&sockets[i].input); - buffer_free(&sockets[i].output); - buffer_free(&sockets[i].request); + close_socket(&sockets[i]); break; } buffer_consume(&sockets[i].output, len); @@ -856,12 +926,7 @@ after_select(fd_set *readset, fd_set *writeset) break; } while (1); if (len <= 0) { - shutdown(sockets[i].fd, SHUT_RDWR); - close(sockets[i].fd); - sockets[i].type = AUTH_UNUSED; - buffer_free(&sockets[i].input); - buffer_free(&sockets[i].output); - buffer_free(&sockets[i].request); + close_socket(&sockets[i]); break; } buffer_append(&sockets[i].input, buf, len); @@ -874,7 +939,7 @@ after_select(fd_set *readset, fd_set *writeset) } static void -cleanup_socket(void *p) +cleanup_socket(void) { if (socket_name[0]) unlink(socket_name); @@ -882,17 +947,17 @@ cleanup_socket(void *p) rmdir(socket_dir); } -static void +void cleanup_exit(int i) { - cleanup_socket(NULL); - exit(i); + cleanup_socket(); + _exit(i); } static void cleanup_handler(int sig) { - cleanup_socket(NULL); + cleanup_socket(); _exit(2); } @@ -905,7 +970,7 @@ check_parent_exists(int sig) /* printf("Parent has died - Authentication agent exiting.\n"); */ cleanup_handler(sig); /* safe */ } - signal(SIGALRM, check_parent_exists); + mysignal(SIGALRM, check_parent_exists); alarm(10); errno = save_errno; } @@ -921,38 +986,44 @@ usage(void) fprintf(stderr, " -k Kill the current agent.\n"); fprintf(stderr, " -d Debug mode.\n"); fprintf(stderr, " -a socket Bind agent socket to given name.\n"); + fprintf(stderr, " -t life Default identity lifetime (seconds).\n"); exit(1); } int main(int ac, char **av) { - int sock, c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0, ch, nalloc; + int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0; + int sock, fd, ch; + u_int nalloc; + char *shell, *format, *pidstr, *agentsocket = NULL; + fd_set *readsetp = NULL, *writesetp = NULL; struct sockaddr_un sunaddr; #ifdef HAVE_SETRLIMIT struct rlimit rlim; #endif -#ifdef HAVE_CYGWIN int prev_mask; -#endif - pid_t pid; - char *shell, *format, *pidstr, pidstrbuf[1 + 3 * sizeof pid]; - char *agentsocket = NULL; - extern char *optarg; extern int optind; - fd_set *readsetp = NULL, *writesetp = NULL; + extern char *optarg; + pid_t pid; + char pidstrbuf[1 + 3 * sizeof pid]; + + /* drop */ + setegid(getgid()); + setgid(getgid()); + +#if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE) + /* Disable ptrace on Linux without sgid bit */ + prctl(PR_SET_DUMPABLE, 0); +#endif SSLeay_add_all_algorithms(); - __progname = get_progname(av[0]); + __progname = ssh_get_progname(av[0]); init_rng(); seed_rng(); -#ifdef __GNU_LIBRARY__ - while ((ch = getopt(ac, av, "+cdksa:")) != -1) { -#else /* __GNU_LIBRARY__ */ - while ((ch = getopt(ac, av, "cdksa:")) != -1) { -#endif /* __GNU_LIBRARY__ */ + while ((ch = getopt(ac, av, "cdksa:t:")) != -1) { switch (ch) { case 'c': if (s_flag) @@ -975,6 +1046,12 @@ main(int ac, char **av) case 'a': agentsocket = optarg; break; + case 't': + if ((lifetime = convtime(optarg)) == -1) { + fprintf(stderr, "Invalid lifetime\n"); + usage(); + } + break; default: usage(); } @@ -1017,7 +1094,7 @@ main(int ac, char **av) if (agentsocket == NULL) { /* Create private directory for agent socket */ - strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir); + strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir); if (mkdtemp(socket_dir) == NULL) { perror("mkdtemp: private socket dir"); exit(1); @@ -1037,25 +1114,21 @@ main(int ac, char **av) sock = socket(AF_UNIX, SOCK_STREAM, 0); if (sock < 0) { perror("socket"); + *socket_name = '\0'; /* Don't unlink any existing file */ cleanup_exit(1); } memset(&sunaddr, 0, sizeof(sunaddr)); sunaddr.sun_family = AF_UNIX; strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); -#ifdef HAVE_CYGWIN prev_mask = umask(0177); -#endif if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { perror("bind"); -#ifdef HAVE_CYGWIN + *socket_name = '\0'; /* Don't unlink any existing file */ umask(prev_mask); -#endif cleanup_exit(1); } -#ifdef HAVE_CYGWIN umask(prev_mask); -#endif - if (listen(sock, 5) < 0) { + if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { perror("listen"); cleanup_exit(1); } @@ -1107,9 +1180,14 @@ main(int ac, char **av) } (void)chdir("/"); - close(0); - close(1); - close(2); + if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { + /* XXX might close listen socket */ + (void)dup2(fd, STDIN_FILENO); + (void)dup2(fd, STDOUT_FILENO); + (void)dup2(fd, STDERR_FILENO); + if (fd > 2) + close(fd); + } #ifdef HAVE_SETRLIMIT /* deny core dumps, since memory contains unencrypted private keys */ @@ -1121,10 +1199,9 @@ main(int ac, char **av) #endif skip: - fatal_add_cleanup(cleanup_socket, NULL); new_socket(AUTH_SOCKET, sock); if (ac > 0) { - signal(SIGALRM, check_parent_exists); + mysignal(SIGALRM, check_parent_exists); alarm(10); } idtab_init();