/* $OpenBSD: misc.c,v 1.163 2021/04/03 05:21:46 djm Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. * Copyright (c) 2005-2020 Damien Miller. All rights reserved. * Copyright (c) 2004 Henning Brauer * * 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. */ #include "includes.h" #include #include #include #include #include #include #include #include #ifdef HAVE_LIBGEN_H # include #endif #ifdef HAVE_POLL_H #include #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef HAVE_PATHS_H # include #include #endif #ifdef SSH_TUN_OPENBSD #include #endif #include "xmalloc.h" #include "misc.h" #include "log.h" #include "ssh.h" #include "sshbuf.h" #include "ssherr.h" #include "platform.h" /* remove newline at end of string */ char * chop(char *s) { char *t = s; while (*t) { if (*t == '\n' || *t == '\r') { *t = '\0'; return s; } t++; } return s; } /* set/unset filedescriptor to non-blocking */ int set_nonblock(int fd) { int val; val = fcntl(fd, F_GETFL); if (val == -1) { error("fcntl(%d, F_GETFL): %s", fd, strerror(errno)); return (-1); } if (val & O_NONBLOCK) { debug3("fd %d is O_NONBLOCK", fd); return (0); } debug2("fd %d setting O_NONBLOCK", fd); val |= O_NONBLOCK; if (fcntl(fd, F_SETFL, val) == -1) { debug("fcntl(%d, F_SETFL, O_NONBLOCK): %s", fd, strerror(errno)); return (-1); } return (0); } int unset_nonblock(int fd) { int val; val = fcntl(fd, F_GETFL); if (val == -1) { error("fcntl(%d, F_GETFL): %s", fd, strerror(errno)); return (-1); } if (!(val & O_NONBLOCK)) { debug3("fd %d is not O_NONBLOCK", fd); return (0); } debug("fd %d clearing O_NONBLOCK", fd); val &= ~O_NONBLOCK; if (fcntl(fd, F_SETFL, val) == -1) { debug("fcntl(%d, F_SETFL, ~O_NONBLOCK): %s", fd, strerror(errno)); return (-1); } return (0); } const char * ssh_gai_strerror(int gaierr) { if (gaierr == EAI_SYSTEM && errno != 0) return strerror(errno); return gai_strerror(gaierr); } /* disable nagle on socket */ void set_nodelay(int fd) { int opt; socklen_t optlen; optlen = sizeof opt; if (getsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, &optlen) == -1) { debug("getsockopt TCP_NODELAY: %.100s", strerror(errno)); return; } if (opt == 1) { debug2("fd %d is TCP_NODELAY", fd); return; } opt = 1; debug2("fd %d setting TCP_NODELAY", fd); if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof opt) == -1) error("setsockopt TCP_NODELAY: %.100s", strerror(errno)); } /* Allow local port reuse in TIME_WAIT */ int set_reuseaddr(int fd) { int on = 1; if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) { error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno)); return -1; } return 0; } /* Get/set routing domain */ char * get_rdomain(int fd) { #if defined(HAVE_SYS_GET_RDOMAIN) return sys_get_rdomain(fd); #elif defined(__OpenBSD__) int rtable; char *ret; socklen_t len = sizeof(rtable); if (getsockopt(fd, SOL_SOCKET, SO_RTABLE, &rtable, &len) == -1) { error("Failed to get routing domain for fd %d: %s", fd, strerror(errno)); return NULL; } xasprintf(&ret, "%d", rtable); return ret; #else /* defined(__OpenBSD__) */ return NULL; #endif } int set_rdomain(int fd, const char *name) { #if defined(HAVE_SYS_SET_RDOMAIN) return sys_set_rdomain(fd, name); #elif defined(__OpenBSD__) int rtable; const char *errstr; if (name == NULL) return 0; /* default table */ rtable = (int)strtonum(name, 0, 255, &errstr); if (errstr != NULL) { /* Shouldn't happen */ error("Invalid routing domain \"%s\": %s", name, errstr); return -1; } if (setsockopt(fd, SOL_SOCKET, SO_RTABLE, &rtable, sizeof(rtable)) == -1) { error("Failed to set routing domain %d on fd %d: %s", rtable, fd, strerror(errno)); return -1; } return 0; #else /* defined(__OpenBSD__) */ error("Setting routing domain is not supported on this platform"); return -1; #endif } int get_sock_af(int fd) { struct sockaddr_storage to; socklen_t tolen = sizeof(to); memset(&to, 0, sizeof(to)); if (getsockname(fd, (struct sockaddr *)&to, &tolen) == -1) return -1; #ifdef IPV4_IN_IPV6 if (to.ss_family == AF_INET6 && IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr)) return AF_INET; #endif return to.ss_family; } void set_sock_tos(int fd, int tos) { #ifndef IP_TOS_IS_BROKEN int af; switch ((af = get_sock_af(fd))) { case -1: /* assume not a socket */ break; case AF_INET: # ifdef IP_TOS debug3_f("set socket %d IP_TOS 0x%02x", fd, tos); if (setsockopt(fd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) == -1) { error("setsockopt socket %d IP_TOS %d: %s:", fd, tos, strerror(errno)); } # endif /* IP_TOS */ break; case AF_INET6: # ifdef IPV6_TCLASS debug3_f("set socket %d IPV6_TCLASS 0x%02x", fd, tos); if (setsockopt(fd, IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) == -1) { error("setsockopt socket %d IPV6_TCLASS %d: %.100s:", fd, tos, strerror(errno)); } # endif /* IPV6_TCLASS */ break; default: debug2_f("unsupported socket family %d", af); break; } #endif /* IP_TOS_IS_BROKEN */ } /* * Wait up to *timeoutp milliseconds for events on fd. Updates * *timeoutp with time remaining. * Returns 0 if fd ready or -1 on timeout or error (see errno). */ static int waitfd(int fd, int *timeoutp, short events) { struct pollfd pfd; struct timeval t_start; int oerrno, r; pfd.fd = fd; pfd.events = events; for (; *timeoutp >= 0;) { monotime_tv(&t_start); r = poll(&pfd, 1, *timeoutp); oerrno = errno; ms_subtract_diff(&t_start, timeoutp); errno = oerrno; if (r > 0) return 0; else if (r == -1 && errno != EAGAIN && errno != EINTR) return -1; else if (r == 0) break; } /* timeout */ errno = ETIMEDOUT; return -1; } /* * Wait up to *timeoutp milliseconds for fd to be readable. Updates * *timeoutp with time remaining. * Returns 0 if fd ready or -1 on timeout or error (see errno). */ int waitrfd(int fd, int *timeoutp) { return waitfd(fd, timeoutp, POLLIN); } /* * Attempt a non-blocking connect(2) to the specified address, waiting up to * *timeoutp milliseconds for the connection to complete. If the timeout is * <=0, then wait indefinitely. * * Returns 0 on success or -1 on failure. */ int timeout_connect(int sockfd, const struct sockaddr *serv_addr, socklen_t addrlen, int *timeoutp) { int optval = 0; socklen_t optlen = sizeof(optval); /* No timeout: just do a blocking connect() */ if (timeoutp == NULL || *timeoutp <= 0) return connect(sockfd, serv_addr, addrlen); set_nonblock(sockfd); for (;;) { if (connect(sockfd, serv_addr, addrlen) == 0) { /* Succeeded already? */ unset_nonblock(sockfd); return 0; } else if (errno == EINTR) continue; else if (errno != EINPROGRESS) return -1; break; } if (waitfd(sockfd, timeoutp, POLLIN | POLLOUT) == -1) return -1; /* Completed or failed */ if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval, &optlen) == -1) { debug("getsockopt: %s", strerror(errno)); return -1; } if (optval != 0) { errno = optval; return -1; } unset_nonblock(sockfd); return 0; } /* Characters considered whitespace in strsep calls. */ #define WHITESPACE " \t\r\n" #define QUOTE "\"" /* return next token in configuration line */ static char * strdelim_internal(char **s, int split_equals) { char *old; int wspace = 0; if (*s == NULL) return NULL; old = *s; *s = strpbrk(*s, split_equals ? WHITESPACE QUOTE "=" : WHITESPACE QUOTE); if (*s == NULL) return (old); if (*s[0] == '\"') { memmove(*s, *s + 1, strlen(*s)); /* move nul too */ /* Find matching quote */ if ((*s = strpbrk(*s, QUOTE)) == NULL) { return (NULL); /* no matching quote */ } else { *s[0] = '\0'; *s += strspn(*s + 1, WHITESPACE) + 1; return (old); } } /* Allow only one '=' to be skipped */ if (split_equals && *s[0] == '=') wspace = 1; *s[0] = '\0'; /* Skip any extra whitespace after first token */ *s += strspn(*s + 1, WHITESPACE) + 1; if (split_equals && *s[0] == '=' && !wspace) *s += strspn(*s + 1, WHITESPACE) + 1; return (old); } /* * Return next token in configuration line; splts on whitespace or a * single '=' character. */ char * strdelim(char **s) { return strdelim_internal(s, 1); } /* * Return next token in configuration line; splts on whitespace only. */ char * strdelimw(char **s) { return strdelim_internal(s, 0); } struct passwd * pwcopy(struct passwd *pw) { struct passwd *copy = xcalloc(1, sizeof(*copy)); copy->pw_name = xstrdup(pw->pw_name); copy->pw_passwd = xstrdup(pw->pw_passwd); #ifdef HAVE_STRUCT_PASSWD_PW_GECOS copy->pw_gecos = xstrdup(pw->pw_gecos); #endif copy->pw_uid = pw->pw_uid; copy->pw_gid = pw->pw_gid; #ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE copy->pw_expire = pw->pw_expire; #endif #ifdef HAVE_STRUCT_PASSWD_PW_CHANGE copy->pw_change = pw->pw_change; #endif #ifdef HAVE_STRUCT_PASSWD_PW_CLASS copy->pw_class = xstrdup(pw->pw_class); #endif copy->pw_dir = xstrdup(pw->pw_dir); copy->pw_shell = xstrdup(pw->pw_shell); return copy; } /* * Convert ASCII string to TCP/IP port number. * Port must be >=0 and <=65535. * Return -1 if invalid. */ int a2port(const char *s) { struct servent *se; long long port; const char *errstr; port = strtonum(s, 0, 65535, &errstr); if (errstr == NULL) return (int)port; if ((se = getservbyname(s, "tcp")) != NULL) return ntohs(se->s_port); return -1; } int a2tun(const char *s, int *remote) { const char *errstr = NULL; char *sp, *ep; int tun; if (remote != NULL) { *remote = SSH_TUNID_ANY; sp = xstrdup(s); if ((ep = strchr(sp, ':')) == NULL) { free(sp); return (a2tun(s, NULL)); } ep[0] = '\0'; ep++; *remote = a2tun(ep, NULL); tun = a2tun(sp, NULL); free(sp); return (*remote == SSH_TUNID_ERR ? *remote : tun); } if (strcasecmp(s, "any") == 0) return (SSH_TUNID_ANY); tun = strtonum(s, 0, SSH_TUNID_MAX, &errstr); if (errstr != NULL) return (SSH_TUNID_ERR); return (tun); } #define SECONDS 1 #define MINUTES (SECONDS * 60) #define HOURS (MINUTES * 60) #define DAYS (HOURS * 24) #define WEEKS (DAYS * 7) /* * Convert a time string into seconds; format is * a sequence of: * time[qualifier] * * Valid time qualifiers are: * seconds * s|S seconds * m|M minutes * h|H hours * d|D days * w|W weeks * * Examples: * 90m 90 minutes * 1h30m 90 minutes * 2d 2 days * 1w 1 week * * Return -1 if time string is invalid. */ int convtime(const char *s) { long total, secs, multiplier; const char *p; char *endp; errno = 0; total = 0; p = s; if (p == NULL || *p == '\0') return -1; while (*p) { secs = strtol(p, &endp, 10); if (p == endp || (errno == ERANGE && (secs == INT_MIN || secs == INT_MAX)) || secs < 0) return -1; multiplier = 1; switch (*endp++) { case '\0': endp--; break; case 's': case 'S': break; case 'm': case 'M': multiplier = MINUTES; break; case 'h': case 'H': multiplier = HOURS; break; case 'd': case 'D': multiplier = DAYS; break; case 'w': case 'W': multiplier = WEEKS; break; default: return -1; } if (secs > INT_MAX / multiplier) return -1; secs *= multiplier; if (total > INT_MAX - secs) return -1; total += secs; if (total < 0) return -1; p = endp; } return total; } #define TF_BUFS 8 #define TF_LEN 9 const char * fmt_timeframe(time_t t) { char *buf; static char tfbuf[TF_BUFS][TF_LEN]; /* ring buffer */ static int idx = 0; unsigned int sec, min, hrs, day; unsigned long long week; buf = tfbuf[idx++]; if (idx == TF_BUFS) idx = 0; week = t; sec = week % 60; week /= 60; min = week % 60; week /= 60; hrs = week % 24; week /= 24; day = week % 7; week /= 7; if (week > 0) snprintf(buf, TF_LEN, "%02lluw%01ud%02uh", week, day, hrs); else if (day > 0) snprintf(buf, TF_LEN, "%01ud%02uh%02um", day, hrs, min); else snprintf(buf, TF_LEN, "%02u:%02u:%02u", hrs, min, sec); return (buf); } /* * Returns a standardized host+port identifier string. * Caller must free returned string. */ char * put_host_port(const char *host, u_short port) { char *hoststr; if (port == 0 || port == SSH_DEFAULT_PORT) return(xstrdup(host)); if (asprintf(&hoststr, "[%s]:%d", host, (int)port) == -1) fatal("put_host_port: asprintf: %s", strerror(errno)); debug3("put_host_port: %s", hoststr); return hoststr; } /* * Search for next delimiter between hostnames/addresses and ports. * Argument may be modified (for termination). * Returns *cp if parsing succeeds. * *cp is set to the start of the next field, if one was found. * The delimiter char, if present, is stored in delim. * If this is the last field, *cp is set to NULL. */ char * hpdelim2(char **cp, char *delim) { char *s, *old; if (cp == NULL || *cp == NULL) return NULL; old = s = *cp; if (*s == '[') { if ((s = strchr(s, ']')) == NULL) return NULL; else s++; } else if ((s = strpbrk(s, ":/")) == NULL) s = *cp + strlen(*cp); /* skip to end (see first case below) */ switch (*s) { case '\0': *cp = NULL; /* no more fields*/ break; case ':': case '/': if (delim != NULL) *delim = *s; *s = '\0'; /* terminate */ *cp = s + 1; break; default: return NULL; } return old; } char * hpdelim(char **cp) { return hpdelim2(cp, NULL); } char * cleanhostname(char *host) { if (*host == '[' && host[strlen(host) - 1] == ']') { host[strlen(host) - 1] = '\0'; return (host + 1); } else return host; } char * colon(char *cp) { int flag = 0; if (*cp == ':') /* Leading colon is part of file name. */ return NULL; if (*cp == '[') flag = 1; for (; *cp; ++cp) { if (*cp == '@' && *(cp+1) == '[') flag = 1; if (*cp == ']' && *(cp+1) == ':' && flag) return (cp+1); if (*cp == ':' && !flag) return (cp); if (*cp == '/') return NULL; } return NULL; } /* * Parse a [user@]host:[path] string. * Caller must free returned user, host and path. * Any of the pointer return arguments may be NULL (useful for syntax checking). * If user was not specified then *userp will be set to NULL. * If host was not specified then *hostp will be set to NULL. * If path was not specified then *pathp will be set to ".". * Returns 0 on success, -1 on failure. */ int parse_user_host_path(const char *s, char **userp, char **hostp, char **pathp) { char *user = NULL, *host = NULL, *path = NULL; char *sdup, *tmp; int ret = -1; if (userp != NULL) *userp = NULL; if (hostp != NULL) *hostp = NULL; if (pathp != NULL) *pathp = NULL; sdup = xstrdup(s); /* Check for remote syntax: [user@]host:[path] */ if ((tmp = colon(sdup)) == NULL) goto out; /* Extract optional path */ *tmp++ = '\0'; if (*tmp == '\0') tmp = "."; path = xstrdup(tmp); /* Extract optional user and mandatory host */ tmp = strrchr(sdup, '@'); if (tmp != NULL) { *tmp++ = '\0'; host = xstrdup(cleanhostname(tmp)); if (*sdup != '\0') user = xstrdup(sdup); } else { host = xstrdup(cleanhostname(sdup)); user = NULL; } /* Success */ if (userp != NULL) { *userp = user; user = NULL; } if (hostp != NULL) { *hostp = host; host = NULL; } if (pathp != NULL) { *pathp = path; path = NULL; } ret = 0; out: free(sdup); free(user); free(host); free(path); return ret; } /* * Parse a [user@]host[:port] string. * Caller must free returned user and host. * Any of the pointer return arguments may be NULL (useful for syntax checking). * If user was not specified then *userp will be set to NULL. * If port was not specified then *portp will be -1. * Returns 0 on success, -1 on failure. */ int parse_user_host_port(const char *s, char **userp, char **hostp, int *portp) { char *sdup, *cp, *tmp; char *user = NULL, *host = NULL; int port = -1, ret = -1; if (userp != NULL) *userp = NULL; if (hostp != NULL) *hostp = NULL; if (portp != NULL) *portp = -1; if ((sdup = tmp = strdup(s)) == NULL) return -1; /* Extract optional username */ if ((cp = strrchr(tmp, '@')) != NULL) { *cp = '\0'; if (*tmp == '\0') goto out; if ((user = strdup(tmp)) == NULL) goto out; tmp = cp + 1; } /* Extract mandatory hostname */ if ((cp = hpdelim(&tmp)) == NULL || *cp == '\0') goto out; host = xstrdup(cleanhostname(cp)); /* Convert and verify optional port */ if (tmp != NULL && *tmp != '\0') { if ((port = a2port(tmp)) <= 0) goto out; } /* Success */ if (userp != NULL) { *userp = user; user = NULL; } if (hostp != NULL) { *hostp = host; host = NULL; } if (portp != NULL) *portp = port; ret = 0; out: free(sdup); free(user); free(host); return ret; } /* * Converts a two-byte hex string to decimal. * Returns the decimal value or -1 for invalid input. */ static int hexchar(const char *s) { unsigned char result[2]; int i; for (i = 0; i < 2; i++) { if (s[i] >= '0' && s[i] <= '9') result[i] = (unsigned char)(s[i] - '0'); else if (s[i] >= 'a' && s[i] <= 'f') result[i] = (unsigned char)(s[i] - 'a') + 10; else if (s[i] >= 'A' && s[i] <= 'F') result[i] = (unsigned char)(s[i] - 'A') + 10; else return -1; } return (result[0] << 4) | result[1]; } /* * Decode an url-encoded string. * Returns a newly allocated string on success or NULL on failure. */ static char * urldecode(const char *src) { char *ret, *dst; int ch; ret = xmalloc(strlen(src) + 1); for (dst = ret; *src != '\0'; src++) { switch (*src) { case '+': *dst++ = ' '; break; case '%': if (!isxdigit((unsigned char)src[1]) || !isxdigit((unsigned char)src[2]) || (ch = hexchar(src + 1)) == -1) { free(ret); return NULL; } *dst++ = ch; src += 2; break; default: *dst++ = *src; break; } } *dst = '\0'; return ret; } /* * Parse an (scp|ssh|sftp)://[user@]host[:port][/path] URI. * See https://tools.ietf.org/html/draft-ietf-secsh-scp-sftp-ssh-uri-04 * Either user or path may be url-encoded (but not host or port). * Caller must free returned user, host and path. * Any of the pointer return arguments may be NULL (useful for syntax checking) * but the scheme must always be specified. * If user was not specified then *userp will be set to NULL. * If port was not specified then *portp will be -1. * If path was not specified then *pathp will be set to NULL. * Returns 0 on success, 1 if non-uri/wrong scheme, -1 on error/invalid uri. */ int parse_uri(const char *scheme, const char *uri, char **userp, char **hostp, int *portp, char **pathp) { char *uridup, *cp, *tmp, ch; char *user = NULL, *host = NULL, *path = NULL; int port = -1, ret = -1; size_t len; len = strlen(scheme); if (strncmp(uri, scheme, len) != 0 || strncmp(uri + len, "://", 3) != 0) return 1; uri += len + 3; if (userp != NULL) *userp = NULL; if (hostp != NULL) *hostp = NULL; if (portp != NULL) *portp = -1; if (pathp != NULL) *pathp = NULL; uridup = tmp = xstrdup(uri); /* Extract optional ssh-info (username + connection params) */ if ((cp = strchr(tmp, '@')) != NULL) { char *delim; *cp = '\0'; /* Extract username and connection params */ if ((delim = strchr(tmp, ';')) != NULL) { /* Just ignore connection params for now */ *delim = '\0'; } if (*tmp == '\0') { /* Empty username */ goto out; } if ((user = urldecode(tmp)) == NULL) goto out; tmp = cp + 1; } /* Extract mandatory hostname */ if ((cp = hpdelim2(&tmp, &ch)) == NULL || *cp == '\0') goto out; host = xstrdup(cleanhostname(cp)); if (!valid_domain(host, 0, NULL)) goto out; if (tmp != NULL && *tmp != '\0') { if (ch == ':') { /* Convert and verify port. */ if ((cp = strchr(tmp, '/')) != NULL) *cp = '\0'; if ((port = a2port(tmp)) <= 0) goto out; tmp = cp ? cp + 1 : NULL; } if (tmp != NULL && *tmp != '\0') { /* Extract optional path */ if ((path = urldecode(tmp)) == NULL) goto out; } } /* Success */ if (userp != NULL) { *userp = user; user = NULL; } if (hostp != NULL) { *hostp = host; host = NULL; } if (portp != NULL) *portp = port; if (pathp != NULL) { *pathp = path; path = NULL; } ret = 0; out: free(uridup); free(user); free(host); free(path); return ret; } /* function to assist building execv() arguments */ void addargs(arglist *args, char *fmt, ...) { va_list ap; char *cp; u_int nalloc; int r; va_start(ap, fmt); r = vasprintf(&cp, fmt, ap); va_end(ap); if (r == -1) fatal("addargs: argument too long"); nalloc = args->nalloc; if (args->list == NULL) { nalloc = 32; args->num = 0; } else if (args->num+2 >= nalloc) nalloc *= 2; args->list = xrecallocarray(args->list, args->nalloc, nalloc, sizeof(char *)); args->nalloc = nalloc; args->list[args->num++] = cp; args->list[args->num] = NULL; } void replacearg(arglist *args, u_int which, char *fmt, ...) { va_list ap; char *cp; int r; va_start(ap, fmt); r = vasprintf(&cp, fmt, ap); va_end(ap); if (r == -1) fatal("replacearg: argument too long"); if (which >= args->num) fatal("replacearg: tried to replace invalid arg %d >= %d", which, args->num); free(args->list[which]); args->list[which] = cp; } void freeargs(arglist *args) { u_int i; if (args->list != NULL) { for (i = 0; i < args->num; i++) free(args->list[i]); free(args->list); args->nalloc = args->num = 0; args->list = NULL; } } /* * Expands tildes in the file name. Returns data allocated by xmalloc. * Warning: this calls getpw*. */ char * tilde_expand_filename(const char *filename, uid_t uid) { const char *path, *sep; char user[128], *ret; struct passwd *pw; u_int len, slash; if (*filename != '~') return (xstrdup(filename)); filename++; path = strchr(filename, '/'); if (path != NULL && path > filename) { /* ~user/path */ slash = path - filename; if (slash > sizeof(user) - 1) fatal("tilde_expand_filename: ~username too long"); memcpy(user, filename, slash); user[slash] = '\0'; if ((pw = getpwnam(user)) == NULL) fatal("tilde_expand_filename: No such user %s", user); } else if ((pw = getpwuid(uid)) == NULL) /* ~/path */ fatal("tilde_expand_filename: No such uid %ld", (long)uid); /* Make sure directory has a trailing '/' */ len = strlen(pw->pw_dir); if (len == 0 || pw->pw_dir[len - 1] != '/') sep = "/"; else sep = ""; /* Skip leading '/' from specified path */ if (path != NULL) filename = path + 1; if (xasprintf(&ret, "%s%s%s", pw->pw_dir, sep, filename) >= PATH_MAX) fatal("tilde_expand_filename: Path too long"); return (ret); } /* * Expand a string with a set of %[char] escapes and/or ${ENVIRONMENT} * substitutions. A number of escapes may be specified as * (char *escape_chars, char *replacement) pairs. The list must be terminated * by a NULL escape_char. Returns replaced string in memory allocated by * xmalloc which the caller must free. */ static char * vdollar_percent_expand(int *parseerror, int dollar, int percent, const char *string, va_list ap) { #define EXPAND_MAX_KEYS 16 u_int num_keys = 0, i; struct { const char *key; const char *repl; } keys[EXPAND_MAX_KEYS]; struct sshbuf *buf; int r, missingvar = 0; char *ret = NULL, *var, *varend, *val; size_t len; if ((buf = sshbuf_new()) == NULL) fatal_f("sshbuf_new failed"); if (parseerror == NULL) fatal_f("null parseerror arg"); *parseerror = 1; /* Gather keys if we're doing percent expansion. */ if (percent) { for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) { keys[num_keys].key = va_arg(ap, char *); if (keys[num_keys].key == NULL) break; keys[num_keys].repl = va_arg(ap, char *); if (keys[num_keys].repl == NULL) { fatal_f("NULL replacement for token %s", keys[num_keys].key); } } if (num_keys == EXPAND_MAX_KEYS && va_arg(ap, char *) != NULL) fatal_f("too many keys"); if (num_keys == 0) fatal_f("percent expansion without token list"); } /* Expand string */ for (i = 0; *string != '\0'; string++) { /* Optionally process ${ENVIRONMENT} expansions. */ if (dollar && string[0] == '$' && string[1] == '{') { string += 2; /* skip over '${' */ if ((varend = strchr(string, '}')) == NULL) { error_f("environment variable '%s' missing " "closing '}'", string); goto out; } len = varend - string; if (len == 0) { error_f("zero-length environment variable"); goto out; } var = xmalloc(len + 1); (void)strlcpy(var, string, len + 1); if ((val = getenv(var)) == NULL) { error_f("env var ${%s} has no value", var); missingvar = 1; } else { debug3_f("expand ${%s} -> '%s'", var, val); if ((r = sshbuf_put(buf, val, strlen(val))) !=0) fatal_fr(r, "sshbuf_put ${}"); } free(var); string += len; continue; } /* * Process percent expansions if we have a list of TOKENs. * If we're not doing percent expansion everything just gets * appended here. */ if (*string != '%' || !percent) { append: if ((r = sshbuf_put_u8(buf, *string)) != 0) fatal_fr(r, "sshbuf_put_u8 %%"); continue; } string++; /* %% case */ if (*string == '%') goto append; if (*string == '\0') { error_f("invalid format"); goto out; } for (i = 0; i < num_keys; i++) { if (strchr(keys[i].key, *string) != NULL) { if ((r = sshbuf_put(buf, keys[i].repl, strlen(keys[i].repl))) != 0) fatal_fr(r, "sshbuf_put %%-repl"); break; } } if (i >= num_keys) { error_f("unknown key %%%c", *string); goto out; } } if (!missingvar && (ret = sshbuf_dup_string(buf)) == NULL) fatal_f("sshbuf_dup_string failed"); *parseerror = 0; out: sshbuf_free(buf); return *parseerror ? NULL : ret; #undef EXPAND_MAX_KEYS } /* * Expand only environment variables. * Note that although this function is variadic like the other similar * functions, any such arguments will be unused. */ char * dollar_expand(int *parseerr, const char *string, ...) { char *ret; int err; va_list ap; va_start(ap, string); ret = vdollar_percent_expand(&err, 1, 0, string, ap); va_end(ap); if (parseerr != NULL) *parseerr = err; return ret; } /* * Returns expanded string or NULL if a specified environment variable is * not defined, or calls fatal if the string is invalid. */ char * percent_expand(const char *string, ...) { char *ret; int err; va_list ap; va_start(ap, string); ret = vdollar_percent_expand(&err, 0, 1, string, ap); va_end(ap); if (err) fatal_f("failed"); return ret; } /* * Returns expanded string or NULL if a specified environment variable is * not defined, or calls fatal if the string is invalid. */ char * percent_dollar_expand(const char *string, ...) { char *ret; int err; va_list ap; va_start(ap, string); ret = vdollar_percent_expand(&err, 1, 1, string, ap); va_end(ap); if (err) fatal_f("failed"); return ret; } int tun_open(int tun, int mode, char **ifname) { #if defined(CUSTOM_SYS_TUN_OPEN) return (sys_tun_open(tun, mode, ifname)); #elif defined(SSH_TUN_OPENBSD) struct ifreq ifr; char name[100]; int fd = -1, sock; const char *tunbase = "tun"; if (ifname != NULL) *ifname = NULL; if (mode == SSH_TUNMODE_ETHERNET) tunbase = "tap"; /* Open the tunnel device */ if (tun <= SSH_TUNID_MAX) { snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun); fd = open(name, O_RDWR); } else if (tun == SSH_TUNID_ANY) { for (tun = 100; tun >= 0; tun--) { snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun); if ((fd = open(name, O_RDWR)) >= 0) break; } } else { debug_f("invalid tunnel %u", tun); return -1; } if (fd == -1) { debug_f("%s open: %s", name, strerror(errno)); return -1; } debug_f("%s mode %d fd %d", name, mode, fd); /* Bring interface up if it is not already */ snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun); if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1) goto failed; if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1) { debug_f("get interface %s flags: %s", ifr.ifr_name, strerror(errno)); goto failed; } if (!(ifr.ifr_flags & IFF_UP)) { ifr.ifr_flags |= IFF_UP; if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1) { debug_f("activate interface %s: %s", ifr.ifr_name, strerror(errno)); goto failed; } } if (ifname != NULL) *ifname = xstrdup(ifr.ifr_name); close(sock); return fd; failed: if (fd >= 0) close(fd); if (sock >= 0) close(sock); return -1; #else error("Tunnel interfaces are not supported on this platform"); return (-1); #endif } void sanitise_stdfd(void) { int nullfd, dupfd; if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) { fprintf(stderr, "Couldn't open /dev/null: %s\n", strerror(errno)); exit(1); } while (++dupfd <= STDERR_FILENO) { /* Only populate closed fds. */ if (fcntl(dupfd, F_GETFL) == -1 && errno == EBADF) { if (dup2(nullfd, dupfd) == -1) { fprintf(stderr, "dup2: %s\n", strerror(errno)); exit(1); } } } if (nullfd > STDERR_FILENO) close(nullfd); } char * tohex(const void *vp, size_t l) { const u_char *p = (const u_char *)vp; char b[3], *r; size_t i, hl; if (l > 65536) return xstrdup("tohex: length > 65536"); hl = l * 2 + 1; r = xcalloc(1, hl); for (i = 0; i < l; i++) { snprintf(b, sizeof(b), "%02x", p[i]); strlcat(r, b, hl); } return (r); } /* * Extend string *sp by the specified format. If *sp is not NULL (or empty), * then the separator 'sep' will be prepended before the formatted arguments. * Extended strings are heap allocated. */ void xextendf(char **sp, const char *sep, const char *fmt, ...) { va_list ap; char *tmp1, *tmp2; va_start(ap, fmt); xvasprintf(&tmp1, fmt, ap); va_end(ap); if (*sp == NULL || **sp == '\0') { free(*sp); *sp = tmp1; return; } xasprintf(&tmp2, "%s%s%s", *sp, sep == NULL ? "" : sep, tmp1); free(tmp1); free(*sp); *sp = tmp2; } u_int64_t get_u64(const void *vp) { const u_char *p = (const u_char *)vp; u_int64_t v; v = (u_int64_t)p[0] << 56; v |= (u_int64_t)p[1] << 48; v |= (u_int64_t)p[2] << 40; v |= (u_int64_t)p[3] << 32; v |= (u_int64_t)p[4] << 24; v |= (u_int64_t)p[5] << 16; v |= (u_int64_t)p[6] << 8; v |= (u_int64_t)p[7]; return (v); } u_int32_t get_u32(const void *vp) { const u_char *p = (const u_char *)vp; u_int32_t v; v = (u_int32_t)p[0] << 24; v |= (u_int32_t)p[1] << 16; v |= (u_int32_t)p[2] << 8; v |= (u_int32_t)p[3]; return (v); } u_int32_t get_u32_le(const void *vp) { const u_char *p = (const u_char *)vp; u_int32_t v; v = (u_int32_t)p[0]; v |= (u_int32_t)p[1] << 8; v |= (u_int32_t)p[2] << 16; v |= (u_int32_t)p[3] << 24; return (v); } u_int16_t get_u16(const void *vp) { const u_char *p = (const u_char *)vp; u_int16_t v; v = (u_int16_t)p[0] << 8; v |= (u_int16_t)p[1]; return (v); } void put_u64(void *vp, u_int64_t v) { u_char *p = (u_char *)vp; p[0] = (u_char)(v >> 56) & 0xff; p[1] = (u_char)(v >> 48) & 0xff; p[2] = (u_char)(v >> 40) & 0xff; p[3] = (u_char)(v >> 32) & 0xff; p[4] = (u_char)(v >> 24) & 0xff; p[5] = (u_char)(v >> 16) & 0xff; p[6] = (u_char)(v >> 8) & 0xff; p[7] = (u_char)v & 0xff; } void put_u32(void *vp, u_int32_t v) { u_char *p = (u_char *)vp; p[0] = (u_char)(v >> 24) & 0xff; p[1] = (u_char)(v >> 16) & 0xff; p[2] = (u_char)(v >> 8) & 0xff; p[3] = (u_char)v & 0xff; } void put_u32_le(void *vp, u_int32_t v) { u_char *p = (u_char *)vp; p[0] = (u_char)v & 0xff; p[1] = (u_char)(v >> 8) & 0xff; p[2] = (u_char)(v >> 16) & 0xff; p[3] = (u_char)(v >> 24) & 0xff; } void put_u16(void *vp, u_int16_t v) { u_char *p = (u_char *)vp; p[0] = (u_char)(v >> 8) & 0xff; p[1] = (u_char)v & 0xff; } void ms_subtract_diff(struct timeval *start, int *ms) { struct timeval diff, finish; monotime_tv(&finish); timersub(&finish, start, &diff); *ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000); } void ms_to_timeval(struct timeval *tv, int ms) { if (ms < 0) ms = 0; tv->tv_sec = ms / 1000; tv->tv_usec = (ms % 1000) * 1000; } void monotime_ts(struct timespec *ts) { struct timeval tv; #if defined(HAVE_CLOCK_GETTIME) && (defined(CLOCK_BOOTTIME) || \ defined(CLOCK_MONOTONIC) || defined(CLOCK_REALTIME)) static int gettime_failed = 0; if (!gettime_failed) { # ifdef CLOCK_BOOTTIME if (clock_gettime(CLOCK_BOOTTIME, ts) == 0) return; # endif /* CLOCK_BOOTTIME */ # ifdef CLOCK_MONOTONIC if (clock_gettime(CLOCK_MONOTONIC, ts) == 0) return; # endif /* CLOCK_MONOTONIC */ # ifdef CLOCK_REALTIME /* Not monotonic, but we're almost out of options here. */ if (clock_gettime(CLOCK_REALTIME, ts) == 0) return; # endif /* CLOCK_REALTIME */ debug3("clock_gettime: %s", strerror(errno)); gettime_failed = 1; } #endif /* HAVE_CLOCK_GETTIME && (BOOTTIME || MONOTONIC || REALTIME) */ gettimeofday(&tv, NULL); ts->tv_sec = tv.tv_sec; ts->tv_nsec = (long)tv.tv_usec * 1000; } void monotime_tv(struct timeval *tv) { struct timespec ts; monotime_ts(&ts); tv->tv_sec = ts.tv_sec; tv->tv_usec = ts.tv_nsec / 1000; } time_t monotime(void) { struct timespec ts; monotime_ts(&ts); return ts.tv_sec; } double monotime_double(void) { struct timespec ts; monotime_ts(&ts); return ts.tv_sec + ((double)ts.tv_nsec / 1000000000); } void bandwidth_limit_init(struct bwlimit *bw, u_int64_t kbps, size_t buflen) { bw->buflen = buflen; bw->rate = kbps; bw->thresh = buflen; bw->lamt = 0; timerclear(&bw->bwstart); timerclear(&bw->bwend); } /* Callback from read/write loop to insert bandwidth-limiting delays */ void bandwidth_limit(struct bwlimit *bw, size_t read_len) { u_int64_t waitlen; struct timespec ts, rm; bw->lamt += read_len; if (!timerisset(&bw->bwstart)) { monotime_tv(&bw->bwstart); return; } if (bw->lamt < bw->thresh) return; monotime_tv(&bw->bwend); timersub(&bw->bwend, &bw->bwstart, &bw->bwend); if (!timerisset(&bw->bwend)) return; bw->lamt *= 8; waitlen = (double)1000000L * bw->lamt / bw->rate; bw->bwstart.tv_sec = waitlen / 1000000L; bw->bwstart.tv_usec = waitlen % 1000000L; if (timercmp(&bw->bwstart, &bw->bwend, >)) { timersub(&bw->bwstart, &bw->bwend, &bw->bwend); /* Adjust the wait time */ if (bw->bwend.tv_sec) { bw->thresh /= 2; if (bw->thresh < bw->buflen / 4) bw->thresh = bw->buflen / 4; } else if (bw->bwend.tv_usec < 10000) { bw->thresh *= 2; if (bw->thresh > bw->buflen * 8) bw->thresh = bw->buflen * 8; } TIMEVAL_TO_TIMESPEC(&bw->bwend, &ts); while (nanosleep(&ts, &rm) == -1) { if (errno != EINTR) break; ts = rm; } } bw->lamt = 0; monotime_tv(&bw->bwstart); } /* Make a template filename for mk[sd]temp() */ void mktemp_proto(char *s, size_t len) { const char *tmpdir; int r; if ((tmpdir = getenv("TMPDIR")) != NULL) { r = snprintf(s, len, "%s/ssh-XXXXXXXXXXXX", tmpdir); if (r > 0 && (size_t)r < len) return; } r = snprintf(s, len, "/tmp/ssh-XXXXXXXXXXXX"); if (r < 0 || (size_t)r >= len) fatal_f("template string too short"); } static const struct { const char *name; int value; } ipqos[] = { { "none", INT_MAX }, /* can't use 0 here; that's CS0 */ { "af11", IPTOS_DSCP_AF11 }, { "af12", IPTOS_DSCP_AF12 }, { "af13", IPTOS_DSCP_AF13 }, { "af21", IPTOS_DSCP_AF21 }, { "af22", IPTOS_DSCP_AF22 }, { "af23", IPTOS_DSCP_AF23 }, { "af31", IPTOS_DSCP_AF31 }, { "af32", IPTOS_DSCP_AF32 }, { "af33", IPTOS_DSCP_AF33 }, { "af41", IPTOS_DSCP_AF41 }, { "af42", IPTOS_DSCP_AF42 }, { "af43", IPTOS_DSCP_AF43 }, { "cs0", IPTOS_DSCP_CS0 }, { "cs1", IPTOS_DSCP_CS1 }, { "cs2", IPTOS_DSCP_CS2 }, { "cs3", IPTOS_DSCP_CS3 }, { "cs4", IPTOS_DSCP_CS4 }, { "cs5", IPTOS_DSCP_CS5 }, { "cs6", IPTOS_DSCP_CS6 }, { "cs7", IPTOS_DSCP_CS7 }, { "ef", IPTOS_DSCP_EF }, { "le", IPTOS_DSCP_LE }, { "lowdelay", IPTOS_LOWDELAY }, { "throughput", IPTOS_THROUGHPUT }, { "reliability", IPTOS_RELIABILITY }, { NULL, -1 } }; int parse_ipqos(const char *cp) { u_int i; char *ep; long val; if (cp == NULL) return -1; for (i = 0; ipqos[i].name != NULL; i++) { if (strcasecmp(cp, ipqos[i].name) == 0) return ipqos[i].value; } /* Try parsing as an integer */ val = strtol(cp, &ep, 0); if (*cp == '\0' || *ep != '\0' || val < 0 || val > 255) return -1; return val; } const char * iptos2str(int iptos) { int i; static char iptos_str[sizeof "0xff"]; for (i = 0; ipqos[i].name != NULL; i++) { if (ipqos[i].value == iptos) return ipqos[i].name; } snprintf(iptos_str, sizeof iptos_str, "0x%02x", iptos); return iptos_str; } void lowercase(char *s) { for (; *s; s++) *s = tolower((u_char)*s); } int unix_listener(const char *path, int backlog, int unlink_first) { struct sockaddr_un sunaddr; int saved_errno, sock; memset(&sunaddr, 0, sizeof(sunaddr)); sunaddr.sun_family = AF_UNIX; if (strlcpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path)) >= sizeof(sunaddr.sun_path)) { error_f("path \"%s\" too long for Unix domain socket", path); errno = ENAMETOOLONG; return -1; } sock = socket(PF_UNIX, SOCK_STREAM, 0); if (sock == -1) { saved_errno = errno; error_f("socket: %.100s", strerror(errno)); errno = saved_errno; return -1; } if (unlink_first == 1) { if (unlink(path) != 0 && errno != ENOENT) error("unlink(%s): %.100s", path, strerror(errno)); } if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1) { saved_errno = errno; error_f("cannot bind to path %s: %s", path, strerror(errno)); close(sock); errno = saved_errno; return -1; } if (listen(sock, backlog) == -1) { saved_errno = errno; error_f("cannot listen on path %s: %s", path, strerror(errno)); close(sock); unlink(path); errno = saved_errno; return -1; } return sock; } void sock_set_v6only(int s) { #if defined(IPV6_V6ONLY) && !defined(__OpenBSD__) int on = 1; debug3("%s: set socket %d IPV6_V6ONLY", __func__, s); if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) == -1) error("setsockopt IPV6_V6ONLY: %s", strerror(errno)); #endif } /* * Compares two strings that maybe be NULL. Returns non-zero if strings * are both NULL or are identical, returns zero otherwise. */ static int strcmp_maybe_null(const char *a, const char *b) { if ((a == NULL && b != NULL) || (a != NULL && b == NULL)) return 0; if (a != NULL && strcmp(a, b) != 0) return 0; return 1; } /* * Compare two forwards, returning non-zero if they are identical or * zero otherwise. */ int forward_equals(const struct Forward *a, const struct Forward *b) { if (strcmp_maybe_null(a->listen_host, b->listen_host) == 0) return 0; if (a->listen_port != b->listen_port) return 0; if (strcmp_maybe_null(a->listen_path, b->listen_path) == 0) return 0; if (strcmp_maybe_null(a->connect_host, b->connect_host) == 0) return 0; if (a->connect_port != b->connect_port) return 0; if (strcmp_maybe_null(a->connect_path, b->connect_path) == 0) return 0; /* allocated_port and handle are not checked */ return 1; } /* returns 1 if process is already daemonized, 0 otherwise */ int daemonized(void) { int fd; if ((fd = open(_PATH_TTY, O_RDONLY | O_NOCTTY)) >= 0) { close(fd); return 0; /* have controlling terminal */ } if (getppid() != 1) return 0; /* parent is not init */ if (getsid(0) != getpid()) return 0; /* not session leader */ debug3("already daemonized"); return 1; } /* * Splits 's' into an argument vector. Handles quoted string and basic * escape characters (\\, \", \'). Caller must free the argument vector * and its members. */ int argv_split(const char *s, int *argcp, char ***argvp) { int r = SSH_ERR_INTERNAL_ERROR; int argc = 0, quote, i, j; char *arg, **argv = xcalloc(1, sizeof(*argv)); *argvp = NULL; *argcp = 0; for (i = 0; s[i] != '\0'; i++) { /* Skip leading whitespace */ if (s[i] == ' ' || s[i] == '\t') continue; /* Start of a token */ quote = 0; argv = xreallocarray(argv, (argc + 2), sizeof(*argv)); arg = argv[argc++] = xcalloc(1, strlen(s + i) + 1); argv[argc] = NULL; /* Copy the token in, removing escapes */ for (j = 0; s[i] != '\0'; i++) { if (s[i] == '\\') { if (s[i + 1] == '\'' || s[i + 1] == '\"' || s[i + 1] == '\\') { i++; /* Skip '\' */ arg[j++] = s[i]; } else { /* Unrecognised escape */ arg[j++] = s[i]; } } else if (quote == 0 && (s[i] == ' ' || s[i] == '\t')) break; /* done */ else if (quote == 0 && (s[i] == '\"' || s[i] == '\'')) quote = s[i]; /* quote start */ else if (quote != 0 && s[i] == quote) quote = 0; /* quote end */ else arg[j++] = s[i]; } if (s[i] == '\0') { if (quote != 0) { /* Ran out of string looking for close quote */ r = SSH_ERR_INVALID_FORMAT; goto out; } break; } } /* Success */ *argcp = argc; *argvp = argv; argc = 0; argv = NULL; r = 0; out: if (argc != 0 && argv != NULL) { for (i = 0; i < argc; i++) free(argv[i]); free(argv); } return r; } /* * Reassemble an argument vector into a string, quoting and escaping as * necessary. Caller must free returned string. */ char * argv_assemble(int argc, char **argv) { int i, j, ws, r; char c, *ret; struct sshbuf *buf, *arg; if ((buf = sshbuf_new()) == NULL || (arg = sshbuf_new()) == NULL) fatal_f("sshbuf_new failed"); for (i = 0; i < argc; i++) { ws = 0; sshbuf_reset(arg); for (j = 0; argv[i][j] != '\0'; j++) { r = 0; c = argv[i][j]; switch (c) { case ' ': case '\t': ws = 1; r = sshbuf_put_u8(arg, c); break; case '\\': case '\'': case '"': if ((r = sshbuf_put_u8(arg, '\\')) != 0) break; /* FALLTHROUGH */ default: r = sshbuf_put_u8(arg, c); break; } if (r != 0) fatal_fr(r, "sshbuf_put_u8"); } if ((i != 0 && (r = sshbuf_put_u8(buf, ' ')) != 0) || (ws != 0 && (r = sshbuf_put_u8(buf, '"')) != 0) || (r = sshbuf_putb(buf, arg)) != 0 || (ws != 0 && (r = sshbuf_put_u8(buf, '"')) != 0)) fatal_fr(r, "assemble"); } if ((ret = malloc(sshbuf_len(buf) + 1)) == NULL) fatal_f("malloc failed"); memcpy(ret, sshbuf_ptr(buf), sshbuf_len(buf)); ret[sshbuf_len(buf)] = '\0'; sshbuf_free(buf); sshbuf_free(arg); return ret; } /* Returns 0 if pid exited cleanly, non-zero otherwise */ int exited_cleanly(pid_t pid, const char *tag, const char *cmd, int quiet) { int status; while (waitpid(pid, &status, 0) == -1) { if (errno != EINTR) { error("%s waitpid: %s", tag, strerror(errno)); return -1; } } if (WIFSIGNALED(status)) { error("%s %s exited on signal %d", tag, cmd, WTERMSIG(status)); return -1; } else if (WEXITSTATUS(status) != 0) { do_log2(quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_INFO, "%s %s failed, status %d", tag, cmd, WEXITSTATUS(status)); return -1; } return 0; } /* * Check a given path for security. This is defined as all components * of the path to the file must be owned by either the owner of * of the file or root and no directories must be group or world writable. * * XXX Should any specific check be done for sym links ? * * Takes a file name, its stat information (preferably from fstat() to * avoid races), the uid of the expected owner, their home directory and an * error buffer plus max size as arguments. * * Returns 0 on success and -1 on failure */ int safe_path(const char *name, struct stat *stp, const char *pw_dir, uid_t uid, char *err, size_t errlen) { char buf[PATH_MAX], homedir[PATH_MAX]; char *cp; int comparehome = 0; struct stat st; if (realpath(name, buf) == NULL) { snprintf(err, errlen, "realpath %s failed: %s", name, strerror(errno)); return -1; } if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL) comparehome = 1; if (!S_ISREG(stp->st_mode)) { snprintf(err, errlen, "%s is not a regular file", buf); return -1; } if ((!platform_sys_dir_uid(stp->st_uid) && stp->st_uid != uid) || (stp->st_mode & 022) != 0) { snprintf(err, errlen, "bad ownership or modes for file %s", buf); return -1; } /* for each component of the canonical path, walking upwards */ for (;;) { if ((cp = dirname(buf)) == NULL) { snprintf(err, errlen, "dirname() failed"); return -1; } strlcpy(buf, cp, sizeof(buf)); if (stat(buf, &st) == -1 || (!platform_sys_dir_uid(st.st_uid) && st.st_uid != uid) || (st.st_mode & 022) != 0) { snprintf(err, errlen, "bad ownership or modes for directory %s", buf); return -1; } /* If are past the homedir then we can stop */ if (comparehome && strcmp(homedir, buf) == 0) break; /* * dirname should always complete with a "/" path, * but we can be paranoid and check for "." too */ if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0)) break; } return 0; } /* * Version of safe_path() that accepts an open file descriptor to * avoid races. * * Returns 0 on success and -1 on failure */ int safe_path_fd(int fd, const char *file, struct passwd *pw, char *err, size_t errlen) { struct stat st; /* check the open file to avoid races */ if (fstat(fd, &st) == -1) { snprintf(err, errlen, "cannot stat file %s: %s", file, strerror(errno)); return -1; } return safe_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen); } /* * Sets the value of the given variable in the environment. If the variable * already exists, its value is overridden. */ void child_set_env(char ***envp, u_int *envsizep, const char *name, const char *value) { char **env; u_int envsize; u_int i, namelen; if (strchr(name, '=') != NULL) { error("Invalid environment variable \"%.100s\"", name); return; } /* * If we're passed an uninitialized list, allocate a single null * entry before continuing. */ if (*envp == NULL && *envsizep == 0) { *envp = xmalloc(sizeof(char *)); *envp[0] = NULL; *envsizep = 1; } /* * Find the slot where the value should be stored. If the variable * already exists, we reuse the slot; otherwise we append a new slot * at the end of the array, expanding if necessary. */ env = *envp; namelen = strlen(name); for (i = 0; env[i]; i++) if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=') break; if (env[i]) { /* Reuse the slot. */ free(env[i]); } else { /* New variable. Expand if necessary. */ envsize = *envsizep; if (i >= envsize - 1) { if (envsize >= 1000) fatal("child_set_env: too many env vars"); envsize += 50; env = (*envp) = xreallocarray(env, envsize, sizeof(char *)); *envsizep = envsize; } /* Need to set the NULL pointer at end of array beyond the new slot. */ env[i + 1] = NULL; } /* Allocate space and format the variable in the appropriate slot. */ /* XXX xasprintf */ env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1); snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value); } /* * Check and optionally lowercase a domain name, also removes trailing '.' * Returns 1 on success and 0 on failure, storing an error message in errstr. */ int valid_domain(char *name, int makelower, const char **errstr) { size_t i, l = strlen(name); u_char c, last = '\0'; static char errbuf[256]; if (l == 0) { strlcpy(errbuf, "empty domain name", sizeof(errbuf)); goto bad; } if (!isalpha((u_char)name[0]) && !isdigit((u_char)name[0])) { snprintf(errbuf, sizeof(errbuf), "domain name \"%.100s\" " "starts with invalid character", name); goto bad; } for (i = 0; i < l; i++) { c = tolower((u_char)name[i]); if (makelower) name[i] = (char)c; if (last == '.' && c == '.') { snprintf(errbuf, sizeof(errbuf), "domain name " "\"%.100s\" contains consecutive separators", name); goto bad; } if (c != '.' && c != '-' && !isalnum(c) && c != '_') /* technically invalid, but common */ { snprintf(errbuf, sizeof(errbuf), "domain name " "\"%.100s\" contains invalid characters", name); goto bad; } last = c; } if (name[l - 1] == '.') name[l - 1] = '\0'; if (errstr != NULL) *errstr = NULL; return 1; bad: if (errstr != NULL) *errstr = errbuf; return 0; } /* * Verify that a environment variable name (not including initial '$') is * valid; consisting of one or more alphanumeric or underscore characters only. * Returns 1 on valid, 0 otherwise. */ int valid_env_name(const char *name) { const char *cp; if (name[0] == '\0') return 0; for (cp = name; *cp != '\0'; cp++) { if (!isalnum((u_char)*cp) && *cp != '_') return 0; } return 1; } const char * atoi_err(const char *nptr, int *val) { const char *errstr = NULL; long long num; if (nptr == NULL || *nptr == '\0') return "missing"; num = strtonum(nptr, 0, INT_MAX, &errstr); if (errstr == NULL) *val = (int)num; return errstr; } int parse_absolute_time(const char *s, uint64_t *tp) { struct tm tm; time_t tt; char buf[32], *fmt; *tp = 0; /* * POSIX strptime says "The application shall ensure that there * is white-space or other non-alphanumeric characters between * any two conversion specifications" so arrange things this way. */ switch (strlen(s)) { case 8: /* YYYYMMDD */ fmt = "%Y-%m-%d"; snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2s", s, s + 4, s + 6); break; case 12: /* YYYYMMDDHHMM */ fmt = "%Y-%m-%dT%H:%M"; snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2sT%.2s:%.2s", s, s + 4, s + 6, s + 8, s + 10); break; case 14: /* YYYYMMDDHHMMSS */ fmt = "%Y-%m-%dT%H:%M:%S"; snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2sT%.2s:%.2s:%.2s", s, s + 4, s + 6, s + 8, s + 10, s + 12); break; default: return SSH_ERR_INVALID_FORMAT; } memset(&tm, 0, sizeof(tm)); if (strptime(buf, fmt, &tm) == NULL) return SSH_ERR_INVALID_FORMAT; if ((tt = mktime(&tm)) < 0) return SSH_ERR_INVALID_FORMAT; /* success */ *tp = (uint64_t)tt; return 0; } void format_absolute_time(uint64_t t, char *buf, size_t len) { time_t tt = t > INT_MAX ? INT_MAX : t; /* XXX revisit in 2038 :P */ struct tm tm; localtime_r(&tt, &tm); strftime(buf, len, "%Y-%m-%dT%H:%M:%S", &tm); } /* check if path is absolute */ int path_absolute(const char *path) { return (*path == '/') ? 1 : 0; } void skip_space(char **cpp) { char *cp; for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) ; *cpp = cp; } /* authorized_key-style options parsing helpers */ /* * Match flag 'opt' in *optsp, and if allow_negate is set then also match * 'no-opt'. Returns -1 if option not matched, 1 if option matches or 0 * if negated option matches. * If the option or negated option matches, then *optsp is updated to * point to the first character after the option. */ int opt_flag(const char *opt, int allow_negate, const char **optsp) { size_t opt_len = strlen(opt); const char *opts = *optsp; int negate = 0; if (allow_negate && strncasecmp(opts, "no-", 3) == 0) { opts += 3; negate = 1; } if (strncasecmp(opts, opt, opt_len) == 0) { *optsp = opts + opt_len; return negate ? 0 : 1; } return -1; } char * opt_dequote(const char **sp, const char **errstrp) { const char *s = *sp; char *ret; size_t i; *errstrp = NULL; if (*s != '"') { *errstrp = "missing start quote"; return NULL; } s++; if ((ret = malloc(strlen((s)) + 1)) == NULL) { *errstrp = "memory allocation failed"; return NULL; } for (i = 0; *s != '\0' && *s != '"';) { if (s[0] == '\\' && s[1] == '"') s++; ret[i++] = *s++; } if (*s == '\0') { *errstrp = "missing end quote"; free(ret); return NULL; } ret[i] = '\0'; s++; *sp = s; return ret; } int opt_match(const char **opts, const char *term) { if (strncasecmp((*opts), term, strlen(term)) == 0 && (*opts)[strlen(term)] == '=') { *opts += strlen(term) + 1; return 1; } return 0; } void opt_array_append2(const char *file, const int line, const char *directive, char ***array, int **iarray, u_int *lp, const char *s, int i) { if (*lp >= INT_MAX) fatal("%s line %d: Too many %s entries", file, line, directive); if (iarray != NULL) { *iarray = xrecallocarray(*iarray, *lp, *lp + 1, sizeof(**iarray)); (*iarray)[*lp] = i; } *array = xrecallocarray(*array, *lp, *lp + 1, sizeof(**array)); (*array)[*lp] = xstrdup(s); (*lp)++; } void opt_array_append(const char *file, const int line, const char *directive, char ***array, u_int *lp, const char *s) { opt_array_append2(file, line, directive, array, NULL, lp, s, 0); } sshsig_t ssh_signal(int signum, sshsig_t handler) { struct sigaction sa, osa; /* mask all other signals while in handler */ memset(&sa, 0, sizeof(sa)); sa.sa_handler = handler; sigfillset(&sa.sa_mask); #if defined(SA_RESTART) && !defined(NO_SA_RESTART) if (signum != SIGALRM) sa.sa_flags = SA_RESTART; #endif if (sigaction(signum, &sa, &osa) == -1) { debug3("sigaction(%s): %s", strsignal(signum), strerror(errno)); return SIG_ERR; } return osa.sa_handler; } int stdfd_devnull(int do_stdin, int do_stdout, int do_stderr) { int devnull, ret = 0; if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) { error_f("open %s: %s", _PATH_DEVNULL, strerror(errno)); return -1; } if ((do_stdin && dup2(devnull, STDIN_FILENO) == -1) || (do_stdout && dup2(devnull, STDOUT_FILENO) == -1) || (do_stderr && dup2(devnull, STDERR_FILENO) == -1)) { error_f("dup2: %s", strerror(errno)); ret = -1; } if (devnull > STDERR_FILENO) close(devnull); return ret; } /* * Runs command in a subprocess with a minimal environment. * Returns pid on success, 0 on failure. * The child stdout and stderr maybe captured, left attached or sent to * /dev/null depending on the contents of flags. * "tag" is prepended to log messages. * NB. "command" is only used for logging; the actual command executed is * av[0]. */ pid_t subprocess(const char *tag, const char *command, int ac, char **av, FILE **child, u_int flags, struct passwd *pw, privdrop_fn *drop_privs, privrestore_fn *restore_privs) { FILE *f = NULL; struct stat st; int fd, devnull, p[2], i; pid_t pid; char *cp, errmsg[512]; u_int nenv = 0; char **env = NULL; /* If dropping privs, then must specify user and restore function */ if (drop_privs != NULL && (pw == NULL || restore_privs == NULL)) { error("%s: inconsistent arguments", tag); /* XXX fatal? */ return 0; } if (pw == NULL && (pw = getpwuid(getuid())) == NULL) { error("%s: no user for current uid", tag); return 0; } if (child != NULL) *child = NULL; debug3_f("%s command \"%s\" running as %s (flags 0x%x)", tag, command, pw->pw_name, flags); /* Check consistency */ if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 && (flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) { error_f("inconsistent flags"); return 0; } if (((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) != (child == NULL)) { error_f("inconsistent flags/output"); return 0; } /* * If executing an explicit binary, then verify the it exists * and appears safe-ish to execute */ if (!path_absolute(av[0])) { error("%s path is not absolute", tag); return 0; } if (drop_privs != NULL) drop_privs(pw); if (stat(av[0], &st) == -1) { error("Could not stat %s \"%s\": %s", tag, av[0], strerror(errno)); goto restore_return; } if ((flags & SSH_SUBPROCESS_UNSAFE_PATH) == 0 && safe_path(av[0], &st, NULL, 0, errmsg, sizeof(errmsg)) != 0) { error("Unsafe %s \"%s\": %s", tag, av[0], errmsg); goto restore_return; } /* Prepare to keep the child's stdout if requested */ if (pipe(p) == -1) { error("%s: pipe: %s", tag, strerror(errno)); restore_return: if (restore_privs != NULL) restore_privs(); return 0; } if (restore_privs != NULL) restore_privs(); switch ((pid = fork())) { case -1: /* error */ error("%s: fork: %s", tag, strerror(errno)); close(p[0]); close(p[1]); return 0; case 0: /* child */ /* Prepare a minimal environment for the child. */ if ((flags & SSH_SUBPROCESS_PRESERVE_ENV) == 0) { nenv = 5; env = xcalloc(sizeof(*env), nenv); child_set_env(&env, &nenv, "PATH", _PATH_STDPATH); child_set_env(&env, &nenv, "USER", pw->pw_name); child_set_env(&env, &nenv, "LOGNAME", pw->pw_name); child_set_env(&env, &nenv, "HOME", pw->pw_dir); if ((cp = getenv("LANG")) != NULL) child_set_env(&env, &nenv, "LANG", cp); } for (i = 1; i < NSIG; i++) ssh_signal(i, SIG_DFL); if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) { error("%s: open %s: %s", tag, _PATH_DEVNULL, strerror(errno)); _exit(1); } if (dup2(devnull, STDIN_FILENO) == -1) { error("%s: dup2: %s", tag, strerror(errno)); _exit(1); } /* Set up stdout as requested; leave stderr in place for now. */ fd = -1; if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) fd = p[1]; else if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0) fd = devnull; if (fd != -1 && dup2(fd, STDOUT_FILENO) == -1) { error("%s: dup2: %s", tag, strerror(errno)); _exit(1); } closefrom(STDERR_FILENO + 1); if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) == -1) { error("%s: setresgid %u: %s", tag, (u_int)pw->pw_gid, strerror(errno)); _exit(1); } if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1) { error("%s: setresuid %u: %s", tag, (u_int)pw->pw_uid, strerror(errno)); _exit(1); } /* stdin is pointed to /dev/null at this point */ if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 && dup2(STDIN_FILENO, STDERR_FILENO) == -1) { error("%s: dup2: %s", tag, strerror(errno)); _exit(1); } if (env != NULL) execve(av[0], av, env); else execv(av[0], av); error("%s %s \"%s\": %s", tag, env == NULL ? "execv" : "execve", command, strerror(errno)); _exit(127); default: /* parent */ break; } close(p[1]); if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) close(p[0]); else if ((f = fdopen(p[0], "r")) == NULL) { error("%s: fdopen: %s", tag, strerror(errno)); close(p[0]); /* Don't leave zombie child */ kill(pid, SIGTERM); while (waitpid(pid, NULL, 0) == -1 && errno == EINTR) ; return 0; } /* Success */ debug3_f("%s pid %ld", tag, (long)pid); if (child != NULL) *child = f; return pid; }