X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/c46e584f7d18c5cec040f3e2477663ba06ab15f9..HEAD:/ssh-agent.c diff --git a/ssh-agent.c b/ssh-agent.c index e1e6cae9..df3a87d9 100644 --- a/ssh-agent.c +++ b/ssh-agent.c @@ -1,3 +1,4 @@ +/* $OpenBSD: ssh-agent.c,v 1.162 2009/09/01 14:43:17 djm Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland @@ -34,29 +35,55 @@ */ #include "includes.h" + +#include +#include +#include +#include +#include +#ifdef HAVE_SYS_TIME_H +# include +#endif +#ifdef HAVE_SYS_UN_H +# include +#endif #include "openbsd-compat/sys-queue.h" -RCSID("$OpenBSD: ssh-agent.c,v 1.112 2003/09/18 08:49:45 markus Exp $"); #include #include +#include "openbsd-compat/openssl-compat.h" +#include +#include +#ifdef HAVE_PATHS_H +# include +#endif +#include +#include +#include +#include +#include +#include +#include + +#include "xmalloc.h" #include "ssh.h" #include "rsa.h" #include "buffer.h" -#include "bufaux.h" -#include "xmalloc.h" -#include "getput.h" #include "key.h" #include "authfd.h" #include "compat.h" #include "log.h" -#include "readpass.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, @@ -94,20 +121,17 @@ int max_fd = 0; /* pid of shell == parent of agent */ pid_t parent_pid = -1; +u_int parent_alive_interval = 0; /* pathname and directory for AUTH_SOCKET */ -char socket_name[1024]; -char socket_dir[1024]; +char socket_name[MAXPATHLEN]; +char socket_dir[MAXPATHLEN]; /* locking */ 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; @@ -169,23 +193,15 @@ lookup_identity(Key *key, int version) static int confirm_key(Identity *id) { - char *p, prompt[1024]; + char *p; int ret = -1; p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); - snprintf(prompt, sizeof(prompt), "Allow use of key %s?\n" - "Key fingerprint %s.", id->comment, p); + if (ask_permission("Allow use of key %s?\nKey fingerprint %s.", + id->comment, p)) + ret = 0; xfree(p); - p = read_passphrase(prompt, RP_ALLOW_EOF); - if (p != NULL) { - /* - * Accept empty responses and responses consisting - * of the word "yes" as affirmative. - */ - if (*p == '\0' || *p == '\n' || strcasecmp(p, "yes") == 0) - ret = 0; - xfree(p); - } + return (ret); } @@ -296,6 +312,7 @@ process_sign_request2(SocketEntry *e) u_char *blob, *data, *signature = NULL; u_int blen, dlen, slen = 0; extern int datafellows; + int odatafellows; int ok = -1, flags; Buffer msg; Key *key; @@ -306,6 +323,7 @@ process_sign_request2(SocketEntry *e) data = buffer_get_string(&e->request, &dlen); flags = buffer_get_int(&e->request); + odatafellows = datafellows; if (flags & SSH_AGENT_OLD_SIGNATURE) datafellows = SSH_BUG_SIGBLOB; @@ -314,8 +332,8 @@ process_sign_request2(SocketEntry *e) Identity *id = lookup_identity(key, 2); if (id != NULL && (!id->confirm || confirm_key(id) == 0)) ok = key_sign(id->key, &signature, &slen, data, dlen); + key_free(key); } - key_free(key); buffer_init(&msg); if (ok == 0) { buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); @@ -331,6 +349,7 @@ process_sign_request2(SocketEntry *e) xfree(blob); if (signature != NULL) xfree(signature); + datafellows = odatafellows; } /* shared */ @@ -364,7 +383,7 @@ process_remove_identity(SocketEntry *e, int version) if (id != NULL) { /* * We have this key. Free the old key. Since we - * don\'t want to leave empty slots in the middle of + * don't want to leave empty slots in the middle of * the array, we actually free the key there and move * all the entries between the empty slot and the end * of the array. @@ -407,10 +426,11 @@ process_remove_all_identities(SocketEntry *e, int version) buffer_put_char(&e->output, SSH_AGENT_SUCCESS); } -static void +/* removes expired keys and returns number of seconds until the next expiry */ +static u_int reaper(void) { - u_int now = time(NULL); + u_int deadline = 0, now = time(NULL); Identity *id, *nxt; int version; Idtab *tab; @@ -419,19 +439,29 @@ reaper(void) tab = idtab_lookup(version); for (id = TAILQ_FIRST(&tab->idlist); id; id = nxt) { nxt = TAILQ_NEXT(id, next); - if (id->death != 0 && now >= id->death) { + if (id->death == 0) + continue; + if (now >= id->death) { + debug("expiring key '%s'", id->comment); TAILQ_REMOVE(&tab->idlist, id, next); free_identity(id); tab->nentries--; - } + } else + deadline = (deadline == 0) ? id->death : + MIN(deadline, id->death); } } + if (deadline == 0 || deadline <= now) + return 0; + else + return (deadline - now); } static void process_add_identity(SocketEntry *e, int version) { Idtab *tab = idtab_lookup(version); + Identity *id; int type, success = 0, death = 0, confirm = 0; char *type_name, *comment; Key *k = NULL; @@ -499,9 +529,8 @@ process_add_identity(SocketEntry *e, int version) xfree(comment); goto send; } - success = 1; while (buffer_len(&e->request)) { - switch (buffer_get_char(&e->request)) { + switch ((type = buffer_get_char(&e->request))) { case SSH_AGENT_CONSTRAIN_LIFETIME: death = time(NULL) + buffer_get_int(&e->request); break; @@ -509,24 +538,29 @@ process_add_identity(SocketEntry *e, int version) confirm = 1; break; default: - break; + error("process_add_identity: " + "Unknown constraint type %d", type); + xfree(comment); + key_free(k); + goto send; } } + success = 1; if (lifetime && !death) death = time(NULL) + lifetime; - if (lookup_identity(k, version) == NULL) { - Identity *id = xmalloc(sizeof(Identity)); + if ((id = lookup_identity(k, version)) == NULL) { + 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++; } else { key_free(k); - xfree(comment); + xfree(id->comment); } + id->comment = comment; + id->death = death; + id->confirm = confirm; send: buffer_put_int(&e->output, 1); buffer_put_char(&e->output, @@ -577,10 +611,10 @@ no_identities(SocketEntry *e, u_int type) #ifdef SMARTCARD static void -process_add_smartcard_key (SocketEntry *e) +process_add_smartcard_key(SocketEntry *e) { char *sc_reader_id = NULL, *pin; - int i, version, success = 0, death = 0, confirm = 0; + int i, type, version, success = 0, death = 0, confirm = 0; Key **keys, *k; Identity *id; Idtab *tab; @@ -589,7 +623,7 @@ process_add_smartcard_key (SocketEntry *e) pin = buffer_get_string(&e->request, NULL); while (buffer_len(&e->request)) { - switch (buffer_get_char(&e->request)) { + switch ((type = buffer_get_char(&e->request))) { case SSH_AGENT_CONSTRAIN_LIFETIME: death = time(NULL) + buffer_get_int(&e->request); break; @@ -597,7 +631,11 @@ process_add_smartcard_key (SocketEntry *e) confirm = 1; break; default: - break; + error("process_add_smartcard_key: " + "Unknown constraint type %d", type); + xfree(sc_reader_id); + xfree(pin); + goto send; } } if (lifetime && !death) @@ -684,13 +722,10 @@ process_message(SocketEntry *e) u_int msg_len, type; u_char *cp; - /* kill dead keys */ - reaper(); - if (buffer_len(&e->input) < 5) return; /* Incomplete message. */ cp = buffer_ptr(&e->input); - msg_len = GET_32BIT(cp); + msg_len = get_u32(cp); if (msg_len > 256 * 1024) { close_socket(e); return; @@ -786,8 +821,7 @@ new_socket(sock_type type, int fd) { u_int i, old_alloc, new_alloc; - if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) - error("fcntl O_NONBLOCK: %s", strerror(errno)); + set_nonblock(fd); if (fd > max_fd) max_fd = fd; @@ -803,10 +837,7 @@ new_socket(sock_type type, int fd) } old_alloc = sockets_alloc; new_alloc = sockets_alloc + 10; - if (sockets) - sockets = xrealloc(sockets, new_alloc * sizeof(sockets[0])); - else - sockets = xmalloc(new_alloc * sizeof(sockets[0])); + sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0])); for (i = old_alloc; i < new_alloc; i++) sockets[i].type = AUTH_UNUSED; sockets_alloc = new_alloc; @@ -818,10 +849,12 @@ new_socket(sock_type type, int fd) } 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, + struct timeval **tvpp) { - u_int i, sz; + u_int i, sz, deadline; int n = 0; + static struct timeval tv; for (i = 0; i < sockets_alloc; i++) { switch (sockets[i].type) { @@ -865,6 +898,17 @@ prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp) break; } } + deadline = reaper(); + if (parent_alive_interval != 0) + deadline = (deadline == 0) ? parent_alive_interval : + MIN(deadline, parent_alive_interval); + if (deadline == 0) { + *tvpp = NULL; + } else { + tv.tv_sec = deadline; + tv.tv_usec = 0; + *tvpp = &tv; + } return (1); } @@ -875,11 +919,11 @@ after_select(fd_set *readset, fd_set *writeset) socklen_t slen; char buf[1024]; int len, sock; - u_int i; + u_int i, orig_alloc; uid_t euid; gid_t egid; - for (i = 0; i < sockets_alloc; i++) + for (i = 0, orig_alloc = sockets_alloc; i < orig_alloc; i++) switch (sockets[i].type) { case AUTH_UNUSED: break; @@ -887,7 +931,7 @@ after_select(fd_set *readset, fd_set *writeset) if (FD_ISSET(sockets[i].fd, readset)) { slen = sizeof(sunaddr); sock = accept(sockets[i].fd, - (struct sockaddr *) &sunaddr, &slen); + (struct sockaddr *)&sunaddr, &slen); if (sock < 0) { error("accept from AUTH_SOCKET: %s", strerror(errno)); @@ -912,15 +956,13 @@ after_select(fd_set *readset, fd_set *writeset) case AUTH_CONNECTION: if (buffer_len(&sockets[i].output) > 0 && FD_ISSET(sockets[i].fd, writeset)) { - do { - len = write(sockets[i].fd, - buffer_ptr(&sockets[i].output), - buffer_len(&sockets[i].output)); - if (len == -1 && (errno == EAGAIN || - errno == EINTR)) - continue; - break; - } while (1); + len = write(sockets[i].fd, + buffer_ptr(&sockets[i].output), + buffer_len(&sockets[i].output)); + if (len == -1 && (errno == EAGAIN || + errno == EWOULDBLOCK || + errno == EINTR)) + continue; if (len <= 0) { close_socket(&sockets[i]); break; @@ -928,13 +970,11 @@ after_select(fd_set *readset, fd_set *writeset) buffer_consume(&sockets[i].output, len); } if (FD_ISSET(sockets[i].fd, readset)) { - do { - len = read(sockets[i].fd, buf, sizeof(buf)); - if (len == -1 && (errno == EAGAIN || - errno == EINTR)) - continue; - break; - } while (1); + len = read(sockets[i].fd, buf, sizeof(buf)); + if (len == -1 && (errno == EAGAIN || + errno == EWOULDBLOCK || + errno == EINTR)) + continue; if (len <= 0) { close_socket(&sockets[i]); break; @@ -949,7 +989,7 @@ after_select(fd_set *readset, fd_set *writeset) } static void -cleanup_socket(void *p) +cleanup_socket(void) { if (socket_name[0]) unlink(socket_name); @@ -957,38 +997,35 @@ cleanup_socket(void *p) rmdir(socket_dir); } -static void +void cleanup_exit(int i) { - cleanup_socket(NULL); - exit(i); + cleanup_socket(); + _exit(i); } +/*ARGSUSED*/ static void cleanup_handler(int sig) { - cleanup_socket(NULL); + cleanup_socket(); _exit(2); } static void -check_parent_exists(int sig) +check_parent_exists(void) { - int save_errno = errno; - if (parent_pid != -1 && kill(parent_pid, 0) < 0) { /* printf("Parent has died - Authentication agent exiting.\n"); */ - cleanup_handler(sig); /* safe */ + cleanup_socket(); + _exit(2); } - mysignal(SIGALRM, check_parent_exists); - alarm(10); - errno = save_errno; } static void usage(void) { - fprintf(stderr, "Usage: %s [options] [command [args ...]]\n", + fprintf(stderr, "usage: %s [options] [command [arg ...]]\n", __progname); fprintf(stderr, "Options:\n"); fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); @@ -1004,25 +1041,34 @@ int main(int ac, char **av) { int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0; - int sock, fd, ch, nalloc; + int sock, fd, ch, result, saved_errno; + 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 extern int optind; extern char *optarg; pid_t pid; char pidstrbuf[1 + 3 * sizeof pid]; + struct timeval *tvp = NULL; + size_t len; + + /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ + sanitise_stdfd(); /* 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 = ssh_get_progname(av[0]); @@ -1070,20 +1116,24 @@ main(int ac, char **av) if (ac == 0 && !c_flag && !s_flag) { shell = getenv("SHELL"); - if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) + if (shell != NULL && (len = strlen(shell)) > 2 && + strncmp(shell + len - 3, "csh", 3) == 0) c_flag = 1; } if (k_flag) { + const char *errstr = NULL; + pidstr = getenv(SSH_AGENTPID_ENV_NAME); if (pidstr == NULL) { fprintf(stderr, "%s not set, cannot kill agent\n", SSH_AGENTPID_ENV_NAME); exit(1); } - pid = atoi(pidstr); - if (pid < 1) { - fprintf(stderr, "%s=\"%s\", which is not a good PID\n", - SSH_AGENTPID_ENV_NAME, pidstr); + pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr); + if (errstr) { + fprintf(stderr, + "%s=\"%s\", which is not a good PID: %s\n", + SSH_AGENTPID_ENV_NAME, pidstr, errstr); exit(1); } if (kill(pid, SIGTERM) == -1) { @@ -1100,7 +1150,7 @@ 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); @@ -1120,25 +1170,21 @@ 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) { + 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, 128) < 0) { + if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { perror("listen"); cleanup_exit(1); } @@ -1209,12 +1255,9 @@ main(int ac, char **av) #endif skip: - fatal_add_cleanup(cleanup_socket, NULL); new_socket(AUTH_SOCKET, sock); - if (ac > 0) { - mysignal(SIGALRM, check_parent_exists); - alarm(10); - } + if (ac > 0) + parent_alive_interval = 10; idtab_init(); if (!d_flag) signal(SIGINT, SIG_IGN); @@ -1224,13 +1267,18 @@ skip: nalloc = 0; while (1) { - prepare_select(&readsetp, &writesetp, &max_fd, &nalloc); - if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) { - if (errno == EINTR) + prepare_select(&readsetp, &writesetp, &max_fd, &nalloc, &tvp); + result = select(max_fd + 1, readsetp, writesetp, NULL, tvp); + saved_errno = errno; + if (parent_alive_interval != 0) + check_parent_exists(); + (void) reaper(); /* remove expired keys */ + if (result < 0) { + if (saved_errno == EINTR) continue; - fatal("select: %s", strerror(errno)); - } - after_select(readsetp, writesetp); + fatal("select: %s", strerror(saved_errno)); + } else if (result > 0) + after_select(readsetp, writesetp); } /* NOTREACHED */ }