diff options
Diffstat (limited to 'crypto/openssh/ssh-keyscan.c')
| -rw-r--r-- | crypto/openssh/ssh-keyscan.c | 851 |
1 files changed, 851 insertions, 0 deletions
diff --git a/crypto/openssh/ssh-keyscan.c b/crypto/openssh/ssh-keyscan.c new file mode 100644 index 0000000..7afe446 --- /dev/null +++ b/crypto/openssh/ssh-keyscan.c @@ -0,0 +1,851 @@ +/* $OpenBSD: ssh-keyscan.c,v 1.81 2010/01/09 23:04:13 dtucker Exp $ */ +/* + * Copyright 1995, 1996 by David Mazieres <dm@lcs.mit.edu>. + * + * Modification and redistribution in source and binary forms is + * permitted provided that due credit is given to the author and the + * OpenBSD project by leaving this copyright notice intact. + */ + +#include "includes.h" + +#include "openbsd-compat/sys-queue.h" +#include <sys/resource.h> +#ifdef HAVE_SYS_TIME_H +# include <sys/time.h> +#endif + +#include <netinet/in.h> +#include <arpa/inet.h> + +#include <openssl/bn.h> + +#include <netdb.h> +#include <errno.h> +#include <setjmp.h> +#include <stdarg.h> +#include <stdio.h> +#include <stdlib.h> +#include <signal.h> +#include <string.h> +#include <unistd.h> + +#include "xmalloc.h" +#include "ssh.h" +#include "ssh1.h" +#include "buffer.h" +#include "key.h" +#include "cipher.h" +#include "kex.h" +#include "compat.h" +#include "myproposal.h" +#include "packet.h" +#include "dispatch.h" +#include "log.h" +#include "atomicio.h" +#include "misc.h" +#include "hostfile.h" + +/* Flag indicating whether IPv4 or IPv6. This can be set on the command line. + Default value is AF_UNSPEC means both IPv4 and IPv6. */ +int IPv4or6 = AF_UNSPEC; + +int ssh_port = SSH_DEFAULT_PORT; + +#define KT_RSA1 1 +#define KT_DSA 2 +#define KT_RSA 4 + +int get_keytypes = KT_RSA; /* Get only RSA keys by default */ + +int hash_hosts = 0; /* Hash hostname on output */ + +#define MAXMAXFD 256 + +/* The number of seconds after which to give up on a TCP connection */ +int timeout = 5; + +int maxfd; +#define MAXCON (maxfd - 10) + +extern char *__progname; +fd_set *read_wait; +size_t read_wait_nfdset; +int ncon; +int nonfatal_fatal = 0; +jmp_buf kexjmp; +Key *kexjmp_key; + +/* + * Keep a connection structure for each file descriptor. The state + * associated with file descriptor n is held in fdcon[n]. + */ +typedef struct Connection { + u_char c_status; /* State of connection on this file desc. */ +#define CS_UNUSED 0 /* File descriptor unused */ +#define CS_CON 1 /* Waiting to connect/read greeting */ +#define CS_SIZE 2 /* Waiting to read initial packet size */ +#define CS_KEYS 3 /* Waiting to read public key packet */ + int c_fd; /* Quick lookup: c->c_fd == c - fdcon */ + int c_plen; /* Packet length field for ssh packet */ + int c_len; /* Total bytes which must be read. */ + int c_off; /* Length of data read so far. */ + int c_keytype; /* Only one of KT_RSA1, KT_DSA, or KT_RSA */ + char *c_namebase; /* Address to free for c_name and c_namelist */ + char *c_name; /* Hostname of connection for errors */ + char *c_namelist; /* Pointer to other possible addresses */ + char *c_output_name; /* Hostname of connection for output */ + char *c_data; /* Data read from this fd */ + Kex *c_kex; /* The key-exchange struct for ssh2 */ + struct timeval c_tv; /* Time at which connection gets aborted */ + TAILQ_ENTRY(Connection) c_link; /* List of connections in timeout order. */ +} con; + +TAILQ_HEAD(conlist, Connection) tq; /* Timeout Queue */ +con *fdcon; + +/* + * This is just a wrapper around fgets() to make it usable. + */ + +/* Stress-test. Increase this later. */ +#define LINEBUF_SIZE 16 + +typedef struct { + char *buf; + u_int size; + int lineno; + const char *filename; + FILE *stream; + void (*errfun) (const char *,...); +} Linebuf; + +static Linebuf * +Linebuf_alloc(const char *filename, void (*errfun) (const char *,...)) +{ + Linebuf *lb; + + if (!(lb = malloc(sizeof(*lb)))) { + if (errfun) + (*errfun) ("linebuf (%s): malloc failed\n", + filename ? filename : "(stdin)"); + return (NULL); + } + if (filename) { + lb->filename = filename; + if (!(lb->stream = fopen(filename, "r"))) { + xfree(lb); + if (errfun) + (*errfun) ("%s: %s\n", filename, strerror(errno)); + return (NULL); + } + } else { + lb->filename = "(stdin)"; + lb->stream = stdin; + } + + if (!(lb->buf = malloc((lb->size = LINEBUF_SIZE)))) { + if (errfun) + (*errfun) ("linebuf (%s): malloc failed\n", lb->filename); + xfree(lb); + return (NULL); + } + lb->errfun = errfun; + lb->lineno = 0; + return (lb); +} + +static void +Linebuf_free(Linebuf * lb) +{ + fclose(lb->stream); + xfree(lb->buf); + xfree(lb); +} + +#if 0 +static void +Linebuf_restart(Linebuf * lb) +{ + clearerr(lb->stream); + rewind(lb->stream); + lb->lineno = 0; +} + +static int +Linebuf_lineno(Linebuf * lb) +{ + return (lb->lineno); +} +#endif + +static char * +Linebuf_getline(Linebuf * lb) +{ + size_t n = 0; + void *p; + + lb->lineno++; + for (;;) { + /* Read a line */ + if (!fgets(&lb->buf[n], lb->size - n, lb->stream)) { + if (ferror(lb->stream) && lb->errfun) + (*lb->errfun)("%s: %s\n", lb->filename, + strerror(errno)); + return (NULL); + } + n = strlen(lb->buf); + + /* Return it or an error if it fits */ + if (n > 0 && lb->buf[n - 1] == '\n') { + lb->buf[n - 1] = '\0'; + return (lb->buf); + } + if (n != lb->size - 1) { + if (lb->errfun) + (*lb->errfun)("%s: skipping incomplete last line\n", + lb->filename); + return (NULL); + } + /* Double the buffer if we need more space */ + lb->size *= 2; + if ((p = realloc(lb->buf, lb->size)) == NULL) { + lb->size /= 2; + if (lb->errfun) + (*lb->errfun)("linebuf (%s): realloc failed\n", + lb->filename); + return (NULL); + } + lb->buf = p; + } +} + +static int +fdlim_get(int hard) +{ +#if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE) + struct rlimit rlfd; + + if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0) + return (-1); + if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY) + return SSH_SYSFDMAX; + else + return hard ? rlfd.rlim_max : rlfd.rlim_cur; +#else + return SSH_SYSFDMAX; +#endif +} + +static int +fdlim_set(int lim) +{ +#if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE) + struct rlimit rlfd; +#endif + + if (lim <= 0) + return (-1); +#if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE) + if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0) + return (-1); + rlfd.rlim_cur = lim; + if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0) + return (-1); +#elif defined (HAVE_SETDTABLESIZE) + setdtablesize(lim); +#endif + return (0); +} + +/* + * This is an strsep function that returns a null field for adjacent + * separators. This is the same as the 4.4BSD strsep, but different from the + * one in the GNU libc. + */ +static char * +xstrsep(char **str, const char *delim) +{ + char *s, *e; + + if (!**str) + return (NULL); + + s = *str; + e = s + strcspn(s, delim); + + if (*e != '\0') + *e++ = '\0'; + *str = e; + + return (s); +} + +/* + * Get the next non-null token (like GNU strsep). Strsep() will return a + * null token for two adjacent separators, so we may have to loop. + */ +static char * +strnnsep(char **stringp, char *delim) +{ + char *tok; + + do { + tok = xstrsep(stringp, delim); + } while (tok && *tok == '\0'); + return (tok); +} + +static Key * +keygrab_ssh1(con *c) +{ + static Key *rsa; + static Buffer msg; + + if (rsa == NULL) { + buffer_init(&msg); + rsa = key_new(KEY_RSA1); + } + buffer_append(&msg, c->c_data, c->c_plen); + buffer_consume(&msg, 8 - (c->c_plen & 7)); /* padding */ + if (buffer_get_char(&msg) != (int) SSH_SMSG_PUBLIC_KEY) { + error("%s: invalid packet type", c->c_name); + buffer_clear(&msg); + return NULL; + } + buffer_consume(&msg, 8); /* cookie */ + + /* server key */ + (void) buffer_get_int(&msg); + buffer_get_bignum(&msg, rsa->rsa->e); + buffer_get_bignum(&msg, rsa->rsa->n); + + /* host key */ + (void) buffer_get_int(&msg); + buffer_get_bignum(&msg, rsa->rsa->e); + buffer_get_bignum(&msg, rsa->rsa->n); + + buffer_clear(&msg); + + return (rsa); +} + +static int +hostjump(Key *hostkey) +{ + kexjmp_key = hostkey; + longjmp(kexjmp, 1); +} + +static int +ssh2_capable(int remote_major, int remote_minor) +{ + switch (remote_major) { + case 1: + if (remote_minor == 99) + return 1; + break; + case 2: + return 1; + default: + break; + } + return 0; +} + +static Key * +keygrab_ssh2(con *c) +{ + int j; + + packet_set_connection(c->c_fd, c->c_fd); + enable_compat20(); + myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = c->c_keytype == KT_DSA? + "ssh-dss": "ssh-rsa"; + c->c_kex = kex_setup(myproposal); + c->c_kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; + c->c_kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; + c->c_kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; + c->c_kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; + c->c_kex->verify_host_key = hostjump; + + if (!(j = setjmp(kexjmp))) { + nonfatal_fatal = 1; + dispatch_run(DISPATCH_BLOCK, &c->c_kex->done, c->c_kex); + fprintf(stderr, "Impossible! dispatch_run() returned!\n"); + exit(1); + } + nonfatal_fatal = 0; + xfree(c->c_kex); + c->c_kex = NULL; + packet_close(); + + return j < 0? NULL : kexjmp_key; +} + +static void +keyprint(con *c, Key *key) +{ + char *host = c->c_output_name ? c->c_output_name : c->c_name; + + if (!key) + return; + if (hash_hosts && (host = host_hash(host, NULL, 0)) == NULL) + fatal("host_hash failed"); + + fprintf(stdout, "%s ", host); + key_write(key, stdout); + fputs("\n", stdout); +} + +static int +tcpconnect(char *host) +{ + struct addrinfo hints, *ai, *aitop; + char strport[NI_MAXSERV]; + int gaierr, s = -1; + + snprintf(strport, sizeof strport, "%d", ssh_port); + memset(&hints, 0, sizeof(hints)); + hints.ai_family = IPv4or6; + hints.ai_socktype = SOCK_STREAM; + if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) + fatal("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr)); + for (ai = aitop; ai; ai = ai->ai_next) { + s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); + if (s < 0) { + error("socket: %s", strerror(errno)); + continue; + } + if (set_nonblock(s) == -1) + fatal("%s: set_nonblock(%d)", __func__, s); + if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 && + errno != EINPROGRESS) + error("connect (`%s'): %s", host, strerror(errno)); + else + break; + close(s); + s = -1; + } + freeaddrinfo(aitop); + return s; +} + +static int +conalloc(char *iname, char *oname, int keytype) +{ + char *namebase, *name, *namelist; + int s; + + namebase = namelist = xstrdup(iname); + + do { + name = xstrsep(&namelist, ","); + if (!name) { + xfree(namebase); + return (-1); + } + } while ((s = tcpconnect(name)) < 0); + + if (s >= maxfd) + fatal("conalloc: fdno %d too high", s); + if (fdcon[s].c_status) + fatal("conalloc: attempt to reuse fdno %d", s); + + fdcon[s].c_fd = s; + fdcon[s].c_status = CS_CON; + fdcon[s].c_namebase = namebase; + fdcon[s].c_name = name; + fdcon[s].c_namelist = namelist; + fdcon[s].c_output_name = xstrdup(oname); + fdcon[s].c_data = (char *) &fdcon[s].c_plen; + fdcon[s].c_len = 4; + fdcon[s].c_off = 0; + fdcon[s].c_keytype = keytype; + gettimeofday(&fdcon[s].c_tv, NULL); + fdcon[s].c_tv.tv_sec += timeout; + TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link); + FD_SET(s, read_wait); + ncon++; + return (s); +} + +static void +confree(int s) +{ + if (s >= maxfd || fdcon[s].c_status == CS_UNUSED) + fatal("confree: attempt to free bad fdno %d", s); + close(s); + xfree(fdcon[s].c_namebase); + xfree(fdcon[s].c_output_name); + if (fdcon[s].c_status == CS_KEYS) + xfree(fdcon[s].c_data); + fdcon[s].c_status = CS_UNUSED; + fdcon[s].c_keytype = 0; + TAILQ_REMOVE(&tq, &fdcon[s], c_link); + FD_CLR(s, read_wait); + ncon--; +} + +static void +contouch(int s) +{ + TAILQ_REMOVE(&tq, &fdcon[s], c_link); + gettimeofday(&fdcon[s].c_tv, NULL); + fdcon[s].c_tv.tv_sec += timeout; + TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link); +} + +static int +conrecycle(int s) +{ + con *c = &fdcon[s]; + int ret; + + ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype); + confree(s); + return (ret); +} + +static void +congreet(int s) +{ + int n = 0, remote_major = 0, remote_minor = 0; + char buf[256], *cp; + char remote_version[sizeof buf]; + size_t bufsiz; + con *c = &fdcon[s]; + + for (;;) { + memset(buf, '\0', sizeof(buf)); + bufsiz = sizeof(buf); + cp = buf; + while (bufsiz-- && + (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') { + if (*cp == '\r') + *cp = '\n'; + cp++; + } + if (n != 1 || strncmp(buf, "SSH-", 4) == 0) + break; + } + if (n == 0) { + switch (errno) { + case EPIPE: + error("%s: Connection closed by remote host", c->c_name); + break; + case ECONNREFUSED: + break; + default: + error("read (%s): %s", c->c_name, strerror(errno)); + break; + } + conrecycle(s); + return; + } + if (*cp != '\n' && *cp != '\r') { + error("%s: bad greeting", c->c_name); + confree(s); + return; + } + *cp = '\0'; + if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", + &remote_major, &remote_minor, remote_version) == 3) + compat_datafellows(remote_version); + else + datafellows = 0; + if (c->c_keytype != KT_RSA1) { + if (!ssh2_capable(remote_major, remote_minor)) { + debug("%s doesn't support ssh2", c->c_name); + confree(s); + return; + } + } else if (remote_major != 1) { + debug("%s doesn't support ssh1", c->c_name); + confree(s); + return; + } + fprintf(stderr, "# %s %s\n", c->c_name, chop(buf)); + n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n", + c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2, + c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2); + if (n < 0 || (size_t)n >= sizeof(buf)) { + error("snprintf: buffer too small"); + confree(s); + return; + } + if (atomicio(vwrite, s, buf, n) != (size_t)n) { + error("write (%s): %s", c->c_name, strerror(errno)); + confree(s); + return; + } + if (c->c_keytype != KT_RSA1) { + keyprint(c, keygrab_ssh2(c)); + confree(s); + return; + } + c->c_status = CS_SIZE; + contouch(s); +} + +static void +conread(int s) +{ + con *c = &fdcon[s]; + size_t n; + + if (c->c_status == CS_CON) { + congreet(s); + return; + } + n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off); + if (n == 0) { + error("read (%s): %s", c->c_name, strerror(errno)); + confree(s); + return; + } + c->c_off += n; + + if (c->c_off == c->c_len) + switch (c->c_status) { + case CS_SIZE: + c->c_plen = htonl(c->c_plen); + c->c_len = c->c_plen + 8 - (c->c_plen & 7); + c->c_off = 0; + c->c_data = xmalloc(c->c_len); + c->c_status = CS_KEYS; + break; + case CS_KEYS: + keyprint(c, keygrab_ssh1(c)); + confree(s); + return; + default: + fatal("conread: invalid status %d", c->c_status); + break; + } + + contouch(s); +} + +static void +conloop(void) +{ + struct timeval seltime, now; + fd_set *r, *e; + con *c; + int i; + + gettimeofday(&now, NULL); + c = TAILQ_FIRST(&tq); + + if (c && (c->c_tv.tv_sec > now.tv_sec || + (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) { + seltime = c->c_tv; + seltime.tv_sec -= now.tv_sec; + seltime.tv_usec -= now.tv_usec; + if (seltime.tv_usec < 0) { + seltime.tv_usec += 1000000; + seltime.tv_sec--; + } + } else + seltime.tv_sec = seltime.tv_usec = 0; + + r = xcalloc(read_wait_nfdset, sizeof(fd_mask)); + e = xcalloc(read_wait_nfdset, sizeof(fd_mask)); + memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask)); + memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask)); + + while (select(maxfd, r, NULL, e, &seltime) == -1 && + (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK)) + ; + + for (i = 0; i < maxfd; i++) { + if (FD_ISSET(i, e)) { + error("%s: exception!", fdcon[i].c_name); + confree(i); + } else if (FD_ISSET(i, r)) + conread(i); + } + xfree(r); + xfree(e); + + c = TAILQ_FIRST(&tq); + while (c && (c->c_tv.tv_sec < now.tv_sec || + (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) { + int s = c->c_fd; + + c = TAILQ_NEXT(c, c_link); + conrecycle(s); + } +} + +static void +do_host(char *host) +{ + char *name = strnnsep(&host, " \t\n"); + int j; + + if (name == NULL) + return; + for (j = KT_RSA1; j <= KT_RSA; j *= 2) { + if (get_keytypes & j) { + while (ncon >= MAXCON) + conloop(); + conalloc(name, *host ? host : name, j); + } + } +} + +void +fatal(const char *fmt,...) +{ + va_list args; + + va_start(args, fmt); + do_log(SYSLOG_LEVEL_FATAL, fmt, args); + va_end(args); + if (nonfatal_fatal) + longjmp(kexjmp, -1); + else + exit(255); +} + +static void +usage(void) +{ + fprintf(stderr, + "usage: %s [-46Hv] [-f file] [-p port] [-T timeout] [-t type]\n" + "\t\t [host | addrlist namelist] ...\n", + __progname); + exit(1); +} + +int +main(int argc, char **argv) +{ + int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO; + int opt, fopt_count = 0; + char *tname; + + extern int optind; + extern char *optarg; + + __progname = ssh_get_progname(argv[0]); + init_rng(); + seed_rng(); + TAILQ_INIT(&tq); + + /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ + sanitise_stdfd(); + + if (argc <= 1) + usage(); + + while ((opt = getopt(argc, argv, "Hv46p:T:t:f:")) != -1) { + switch (opt) { + case 'H': + hash_hosts = 1; + break; + case 'p': + ssh_port = a2port(optarg); + if (ssh_port <= 0) { + fprintf(stderr, "Bad port '%s'\n", optarg); + exit(1); + } + break; + case 'T': + timeout = convtime(optarg); + if (timeout == -1 || timeout == 0) { + fprintf(stderr, "Bad timeout '%s'\n", optarg); + usage(); + } + break; + case 'v': + if (!debug_flag) { + debug_flag = 1; + log_level = SYSLOG_LEVEL_DEBUG1; + } + else if (log_level < SYSLOG_LEVEL_DEBUG3) + log_level++; + else + fatal("Too high debugging level."); + break; + case 'f': + if (strcmp(optarg, "-") == 0) + optarg = NULL; + argv[fopt_count++] = optarg; + break; + case 't': + get_keytypes = 0; + tname = strtok(optarg, ","); + while (tname) { + int type = key_type_from_name(tname); + switch (type) { + case KEY_RSA1: + get_keytypes |= KT_RSA1; + break; + case KEY_DSA: + get_keytypes |= KT_DSA; + break; + case KEY_RSA: + get_keytypes |= KT_RSA; + break; + case KEY_UNSPEC: + fatal("unknown key type %s", tname); + } + tname = strtok(NULL, ","); + } + break; + case '4': + IPv4or6 = AF_INET; + break; + case '6': + IPv4or6 = AF_INET6; + break; + case '?': + default: + usage(); + } + } + if (optind == argc && !fopt_count) + usage(); + + log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1); + + maxfd = fdlim_get(1); + if (maxfd < 0) + fatal("%s: fdlim_get: bad value", __progname); + if (maxfd > MAXMAXFD) + maxfd = MAXMAXFD; + if (MAXCON <= 0) + fatal("%s: not enough file descriptors", __progname); + if (maxfd > fdlim_get(0)) + fdlim_set(maxfd); + fdcon = xcalloc(maxfd, sizeof(con)); + + read_wait_nfdset = howmany(maxfd, NFDBITS); + read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask)); + + if (fopt_count) { + Linebuf *lb; + char *line; + int j; + + for (j = 0; j < fopt_count; j++) { + lb = Linebuf_alloc(argv[j], error); + if (!lb) + continue; + while ((line = Linebuf_getline(lb)) != NULL) + do_host(line); + Linebuf_free(lb); + } + } + + while (optind < argc) + do_host(argv[optind++]); + + while (ncon > 0) + conloop(); + + return (0); +} |
