/* * Copyright (c) 2000 Andre Lucas. All rights reserved. * Portions copyright (c) 1998 Todd C. Miller * Portions copyright (c) 1996 Jason Downs * Portions copyright (c) 1996 Theo de Raadt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /** ** loginrec.c: platform-independent login recording and lastlog retrieval **/ /* * The new login code explained * ============================ * * This code attempts to provide a common interface to login recording * (utmp and friends) and last login time retrieval. * * Its primary means of achieving this is to use 'struct logininfo', a * union of all the useful fields in the various different types of * system login record structures one finds on UNIX variants. * * We depend on autoconf to define which recording methods are to be * used, and which fields are contained in the relevant data structures * on the local system. Many C preprocessor symbols affect which code * gets compiled here. * * The code is designed to make it easy to modify a particular * recording method, without affecting other methods nor requiring so * many nested conditional compilation blocks as were commonplace in * the old code. * * For login recording, we try to use the local system's libraries as * these are clearly most likely to work correctly. For utmp systems * this usually means login() and logout() or setutent() etc., probably * in libutil, along with logwtmp() etc. On these systems, we fall back * to writing the files directly if we have to, though this method * requires very thorough testing so we do not corrupt local auditing * information. These files and their access methods are very system * specific indeed. * * For utmpx systems, the corresponding library functions are * setutxent() etc. To the author's knowledge, all utmpx systems have * these library functions and so no direct write is attempted. If such * a system exists and needs support, direct analogues of the [uw]tmp * code should suffice. * * Retrieving the time of last login ('lastlog') is in some ways even * more problemmatic than login recording. Some systems provide a * simple table of all users which we seek based on uid and retrieve a * relatively standard structure. Others record the same information in * a directory with a separate file, and others don't record the * information separately at all. For systems in the latter category, * we look backwards in the wtmp or wtmpx file for the last login entry * for our user. Naturally this is slower and on busy systems could * incur a significant performance penalty. * * Calling the new code * -------------------- * * In OpenSSH all login recording and retrieval is performed in * login.c. Here you'll find working examples. Also, in the logintest.c * program there are more examples. * * Internal handler calling method * ------------------------------- * * When a call is made to login_login() or login_logout(), both * routines set a struct logininfo flag defining which action (log in, * or log out) is to be taken. They both then call login_write(), which * calls whichever of the many structure-specific handlers autoconf * selects for the local system. * * The handlers themselves handle system data structure specifics. Both * struct utmp and struct utmpx have utility functions (see * construct_utmp*()) to try to make it simpler to add extra systems * that introduce new features to either structure. * * While it may seem terribly wasteful to replicate so much similar * code for each method, experience has shown that maintaining code to * write both struct utmp and utmpx in one function, whilst maintaining * support for all systems whether they have library support or not, is * a difficult and time-consuming task. * * Lastlog support proceeds similarly. Functions login_get_lastlog() * (and its OpenSSH-tuned friend login_get_lastlog_time()) call * getlast_entry(), which tries one of three methods to find the last * login time. It uses local system lastlog support if it can, * otherwise it tries wtmp or wtmpx before giving up and returning 0, * meaning "tilt". * * Maintenance * ----------- * * In many cases it's possible to tweak autoconf to select the correct * methods for a particular platform, either by improving the detection * code (best), or by presetting DISABLE_ or CONF__FILE * symbols for the platform. * * Use logintest to check which symbols are defined before modifying * configure.ac and loginrec.c. (You have to build logintest yourself * with 'make logintest' as it's not built by default.) * * Otherwise, patches to the specific method(s) are very helpful! */ #include "includes.h" #include #include #include #ifdef HAVE_SYS_TIME_H # include #endif #include #include #include #include #ifdef HAVE_PATHS_H # include #endif #include #include #include #include #include #include #include "xmalloc.h" #include "sshkey.h" #include "hostfile.h" #include "ssh.h" #include "loginrec.h" #include "log.h" #include "atomicio.h" #include "packet.h" #include "canohost.h" #include "auth.h" #include "sshbuf.h" #include "ssherr.h" #include "misc.h" #ifdef HAVE_UTIL_H # include #endif /** ** prototypes for helper functions in this file **/ #if HAVE_UTMP_H void set_utmp_time(struct logininfo *li, struct utmp *ut); void construct_utmp(struct logininfo *li, struct utmp *ut); #endif #ifdef HAVE_UTMPX_H void set_utmpx_time(struct logininfo *li, struct utmpx *ut); void construct_utmpx(struct logininfo *li, struct utmpx *ut); #endif int utmp_write_entry(struct logininfo *li); int utmpx_write_entry(struct logininfo *li); int wtmp_write_entry(struct logininfo *li); int wtmpx_write_entry(struct logininfo *li); int lastlog_write_entry(struct logininfo *li); int syslogin_write_entry(struct logininfo *li); int getlast_entry(struct logininfo *li); int lastlog_get_entry(struct logininfo *li); int utmpx_get_entry(struct logininfo *li); int wtmp_get_entry(struct logininfo *li); int wtmpx_get_entry(struct logininfo *li); extern struct sshbuf *loginmsg; /* pick the shortest string */ #define MIN_SIZEOF(s1,s2) (sizeof(s1) < sizeof(s2) ? sizeof(s1) : sizeof(s2)) /** ** platform-independent login functions **/ /* * login_login(struct logininfo *) - Record a login * * Call with a pointer to a struct logininfo initialised with * login_init_entry() or login_alloc_entry() * * Returns: * >0 if successful * 0 on failure (will use OpenSSH's logging facilities for diagnostics) */ int login_login(struct logininfo *li) { li->type = LTYPE_LOGIN; return (login_write(li)); } /* * login_logout(struct logininfo *) - Record a logout * * Call as with login_login() * * Returns: * >0 if successful * 0 on failure (will use OpenSSH's logging facilities for diagnostics) */ int login_logout(struct logininfo *li) { li->type = LTYPE_LOGOUT; return (login_write(li)); } /* * login_get_lastlog_time(int) - Retrieve the last login time * * Retrieve the last login time for the given uid. Will try to use the * system lastlog facilities if they are available, but will fall back * to looking in wtmp/wtmpx if necessary * * Returns: * 0 on failure, or if user has never logged in * Time in seconds from the epoch if successful * * Useful preprocessor symbols: * DISABLE_LASTLOG: If set, *never* even try to retrieve lastlog * info * USE_LASTLOG: If set, indicates the presence of system lastlog * facilities. If this and DISABLE_LASTLOG are not set, * try to retrieve lastlog information from wtmp/wtmpx. */ unsigned int login_get_lastlog_time(const uid_t uid) { struct logininfo li; if (login_get_lastlog(&li, uid)) return (li.tv_sec); else return (0); } /* * login_get_lastlog(struct logininfo *, int) - Retrieve a lastlog entry * * Retrieve a logininfo structure populated (only partially) with * information from the system lastlog data, or from wtmp/wtmpx if no * system lastlog information exists. * * Note this routine must be given a pre-allocated logininfo. * * Returns: * >0: A pointer to your struct logininfo if successful * 0 on failure (will use OpenSSH's logging facilities for diagnostics) */ struct logininfo * login_get_lastlog(struct logininfo *li, const uid_t uid) { struct passwd *pw; memset(li, '\0', sizeof(*li)); li->uid = uid; /* * If we don't have a 'real' lastlog, we need the username to * reliably search wtmp(x) for the last login (see * wtmp_get_entry().) */ pw = getpwuid(uid); if (pw == NULL) fatal("%s: Cannot find account for uid %ld", __func__, (long)uid); if (strlcpy(li->username, pw->pw_name, sizeof(li->username)) >= sizeof(li->username)) { error("%s: username too long (%lu > max %lu)", __func__, (unsigned long)strlen(pw->pw_name), (unsigned long)sizeof(li->username) - 1); return NULL; } if (getlast_entry(li)) return (li); else return (NULL); } /* * login_alloc_entry(int, char*, char*, char*) - Allocate and initialise * a logininfo structure * * This function creates a new struct logininfo, a data structure * meant to carry the information required to portably record login info. * * Returns a pointer to a newly created struct logininfo. If memory * allocation fails, the program halts. */ struct logininfo *login_alloc_entry(pid_t pid, const char *username, const char *hostname, const char *line) { struct logininfo *newli; newli = xmalloc(sizeof(*newli)); login_init_entry(newli, pid, username, hostname, line); return (newli); } /* login_free_entry(struct logininfo *) - free struct memory */ void login_free_entry(struct logininfo *li) { free(li); } /* login_init_entry(struct logininfo *, int, char*, char*, char*) * - initialise a struct logininfo * * Populates a new struct logininfo, a data structure meant to carry * the information required to portably record login info. * * Returns: 1 */ int login_init_entry(struct logininfo *li, pid_t pid, const char *username, const char *hostname, const char *line) { struct passwd *pw; memset(li, 0, sizeof(*li)); li->pid = pid; /* set the line information */ if (line) line_fullname(li->line, line, sizeof(li->line)); if (username) { strlcpy(li->username, username, sizeof(li->username)); pw = getpwnam(li->username); if (pw == NULL) { fatal("%s: Cannot find user \"%s\"", __func__, li->username); } li->uid = pw->pw_uid; } if (hostname) strlcpy(li->hostname, hostname, sizeof(li->hostname)); return (1); } /* * login_set_current_time(struct logininfo *) - set the current time * * Set the current time in a logininfo structure. This function is * meant to eliminate the need to deal with system dependencies for * time handling. */ void login_set_current_time(struct logininfo *li) { struct timeval tv; gettimeofday(&tv, NULL); li->tv_sec = tv.tv_sec; li->tv_usec = tv.tv_usec; } /* copy a sockaddr_* into our logininfo */ void login_set_addr(struct logininfo *li, const struct sockaddr *sa, const unsigned int sa_size) { unsigned int bufsize = sa_size; /* make sure we don't overrun our union */ if (sizeof(li->hostaddr) < sa_size) bufsize = sizeof(li->hostaddr); memcpy(&li->hostaddr.sa, sa, bufsize); } /** ** login_write: Call low-level recording functions based on autoconf ** results **/ int login_write(struct logininfo *li) { #ifndef HAVE_CYGWIN if (geteuid() != 0) { logit("Attempt to write login records by non-root user (aborting)"); return (1); } #endif /* set the timestamp */ login_set_current_time(li); #ifdef USE_LOGIN syslogin_write_entry(li); #endif #ifdef USE_LASTLOG if (li->type == LTYPE_LOGIN) lastlog_write_entry(li); #endif #ifdef USE_UTMP utmp_write_entry(li); #endif #ifdef USE_WTMP wtmp_write_entry(li); #endif #ifdef USE_UTMPX utmpx_write_entry(li); #endif #ifdef USE_WTMPX wtmpx_write_entry(li); #endif #ifdef CUSTOM_SYS_AUTH_RECORD_LOGIN if (li->type == LTYPE_LOGIN && !sys_auth_record_login(li->username,li->hostname,li->line, loginmsg)) logit("Writing login record failed for %s", li->username); #endif #ifdef SSH_AUDIT_EVENTS if (li->type == LTYPE_LOGIN) audit_session_open(li); else if (li->type == LTYPE_LOGOUT) audit_session_close(li); #endif return (0); } #ifdef LOGIN_NEEDS_UTMPX int login_utmp_only(struct logininfo *li) { li->type = LTYPE_LOGIN; login_set_current_time(li); # ifdef USE_UTMP utmp_write_entry(li); # endif # ifdef USE_WTMP wtmp_write_entry(li); # endif # ifdef USE_UTMPX utmpx_write_entry(li); # endif # ifdef USE_WTMPX wtmpx_write_entry(li); # endif return (0); } #endif /** ** getlast_entry: Call low-level functions to retrieve the last login ** time. **/ /* take the uid in li and return the last login time */ int getlast_entry(struct logininfo *li) { #ifdef USE_LASTLOG return(lastlog_get_entry(li)); #else /* !USE_LASTLOG */ #if defined(USE_UTMPX) && defined(HAVE_SETUTXDB) && \ defined(UTXDB_LASTLOGIN) && defined(HAVE_GETUTXUSER) return (utmpx_get_entry(li)); #endif #if defined(DISABLE_LASTLOG) /* On some systems we shouldn't even try to obtain last login * time, e.g. AIX */ return (0); # elif defined(USE_WTMP) && \ (defined(HAVE_TIME_IN_UTMP) || defined(HAVE_TV_IN_UTMP)) /* retrieve last login time from utmp */ return (wtmp_get_entry(li)); # elif defined(USE_WTMPX) && \ (defined(HAVE_TIME_IN_UTMPX) || defined(HAVE_TV_IN_UTMPX)) /* If wtmp isn't available, try wtmpx */ return (wtmpx_get_entry(li)); # else /* Give up: No means of retrieving last login time */ return (0); # endif /* DISABLE_LASTLOG */ #endif /* USE_LASTLOG */ } /* * 'line' string utility functions * * These functions process the 'line' string into one of three forms: * * 1. The full filename (including '/dev') * 2. The stripped name (excluding '/dev') * 3. The abbreviated name (e.g. /dev/ttyp00 -> yp00 * /dev/pts/1 -> ts/1 ) * * Form 3 is used on some systems to identify a .tmp.? entry when * attempting to remove it. Typically both addition and removal is * performed by one application - say, sshd - so as long as the choice * uniquely identifies a terminal it's ok. */ /* * line_fullname(): add the leading '/dev/' if it doesn't exist make * sure dst has enough space, if not just copy src (ugh) */ char * line_fullname(char *dst, const char *src, u_int dstsize) { memset(dst, '\0', dstsize); if ((strncmp(src, "/dev/", 5) == 0) || (dstsize < (strlen(src) + 5))) strlcpy(dst, src, dstsize); else { strlcpy(dst, "/dev/", dstsize); strlcat(dst, src, dstsize); } return (dst); } /* line_stripname(): strip the leading '/dev' if it exists, return dst */ char * line_stripname(char *dst, const char *src, int dstsize) { memset(dst, '\0', dstsize); if (strncmp(src, "/dev/", 5) == 0) strlcpy(dst, src + 5, dstsize); else strlcpy(dst, src, dstsize); return (dst); } /* * line_abbrevname(): Return the abbreviated (usually four-character) * form of the line (Just use the last characters of the * full name.) * * NOTE: use strncpy because we do NOT necessarily want zero * termination */ char * line_abbrevname(char *dst, const char *src, int dstsize) { size_t len; memset(dst, '\0', dstsize); if (strcmp(src, "ssh:notty") == 0) return dst; /* Always skip prefix if present */ if (strncmp(src, "/dev/", 5) == 0) src += 5; #ifdef WITH_ABBREV_NO_TTY if (strncmp(src, "tty", 3) == 0) src += 3; #endif len = strlen(src); if (len > 0) { if (((int)len - dstsize) > 0) src += ((int)len - dstsize); /* note: _don't_ change this to strlcpy */ strncpy(dst, src, (size_t)dstsize); } return (dst); } /** ** utmp utility functions ** ** These functions manipulate struct utmp, taking system differences ** into account. **/ #if defined(USE_UTMP) || defined (USE_WTMP) || defined (USE_LOGIN) /* build the utmp structure */ void set_utmp_time(struct logininfo *li, struct utmp *ut) { # if defined(HAVE_TV_IN_UTMP) ut->ut_tv.tv_sec = li->tv_sec; ut->ut_tv.tv_usec = li->tv_usec; # elif defined(HAVE_TIME_IN_UTMP) ut->ut_time = li->tv_sec; # endif } void construct_utmp(struct logininfo *li, struct utmp *ut) { # ifdef HAVE_ADDR_V6_IN_UTMP struct sockaddr_in6 *sa6; # endif memset(ut, '\0', sizeof(*ut)); /* First fill out fields used for both logins and logouts */ # ifdef HAVE_ID_IN_UTMP line_abbrevname(ut->ut_id, li->line, sizeof(ut->ut_id)); # endif # ifdef HAVE_TYPE_IN_UTMP /* This is done here to keep utmp constants out of struct logininfo */ switch (li->type) { case LTYPE_LOGIN: ut->ut_type = USER_PROCESS; break; case LTYPE_LOGOUT: ut->ut_type = DEAD_PROCESS; break; } # endif set_utmp_time(li, ut); line_stripname(ut->ut_line, li->line, sizeof(ut->ut_line)); # ifdef HAVE_PID_IN_UTMP ut->ut_pid = li->pid; # endif /* If we're logging out, leave all other fields blank */ if (li->type == LTYPE_LOGOUT) return; /* * These fields are only used when logging in, and are blank * for logouts. */ /* Use strncpy because we don't necessarily want null termination */ strncpy(ut->ut_name, li->username, MIN_SIZEOF(ut->ut_name, li->username)); # ifdef HAVE_HOST_IN_UTMP strncpy(ut->ut_host, li->hostname, MIN_SIZEOF(ut->ut_host, li->hostname)); # endif # ifdef HAVE_ADDR_IN_UTMP /* this is just a 32-bit IP address */ if (li->hostaddr.sa.sa_family == AF_INET) ut->ut_addr = li->hostaddr.sa_in.sin_addr.s_addr; # endif # ifdef HAVE_ADDR_V6_IN_UTMP /* this is just a 128-bit IPv6 address */ if (li->hostaddr.sa.sa_family == AF_INET6) { sa6 = ((struct sockaddr_in6 *)&li->hostaddr.sa); memcpy(ut->ut_addr_v6, sa6->sin6_addr.s6_addr, 16); if (IN6_IS_ADDR_V4MAPPED(&sa6->sin6_addr)) { ut->ut_addr_v6[0] = ut->ut_addr_v6[3]; ut->ut_addr_v6[1] = 0; ut->ut_addr_v6[2] = 0; ut->ut_addr_v6[3] = 0; } } # endif } #endif /* USE_UTMP || USE_WTMP || USE_LOGIN */ /** ** utmpx utility functions ** ** These functions manipulate struct utmpx, accounting for system ** variations. **/ #if defined(USE_UTMPX) || defined (USE_WTMPX) /* build the utmpx structure */ void set_utmpx_time(struct logininfo *li, struct utmpx *utx) { # if defined(HAVE_TV_IN_UTMPX) utx->ut_tv.tv_sec = li->tv_sec; utx->ut_tv.tv_usec = li->tv_usec; # elif defined(HAVE_TIME_IN_UTMPX) utx->ut_time = li->tv_sec; # endif } void construct_utmpx(struct logininfo *li, struct utmpx *utx) { # ifdef HAVE_ADDR_V6_IN_UTMP struct sockaddr_in6 *sa6; # endif memset(utx, '\0', sizeof(*utx)); # ifdef HAVE_ID_IN_UTMPX line_abbrevname(utx->ut_id, li->line, sizeof(utx->ut_id)); # endif /* this is done here to keep utmp constants out of loginrec.h */ switch (li->type) { case LTYPE_LOGIN: utx->ut_type = USER_PROCESS; break; case LTYPE_LOGOUT: utx->ut_type = DEAD_PROCESS; break; } line_stripname(utx->ut_line, li->line, sizeof(utx->ut_line)); set_utmpx_time(li, utx); utx->ut_pid = li->pid; /* strncpy(): Don't necessarily want null termination */ strncpy(utx->ut_user, li->username, MIN_SIZEOF(utx->ut_user, li->username)); if (li->type == LTYPE_LOGOUT) return; /* * These fields are only used when logging in, and are blank * for logouts. */ # ifdef HAVE_HOST_IN_UTMPX strncpy(utx->ut_host, li->hostname, MIN_SIZEOF(utx->ut_host, li->hostname)); # endif # ifdef HAVE_SS_IN_UTMPX utx->ut_ss = li->hostaddr.sa_storage; # endif # ifdef HAVE_ADDR_IN_UTMPX /* this is just a 32-bit IP address */ if (li->hostaddr.sa.sa_family == AF_INET) utx->ut_addr = li->hostaddr.sa_in.sin_addr.s_addr; # endif # ifdef HAVE_ADDR_V6_IN_UTMP /* this is just a 128-bit IPv6 address */ if (li->hostaddr.sa.sa_family == AF_INET6) { sa6 = ((struct sockaddr_in6 *)&li->hostaddr.sa); memcpy(utx->ut_addr_v6, sa6->sin6_addr.s6_addr, 16); if (IN6_IS_ADDR_V4MAPPED(&sa6->sin6_addr)) { utx->ut_addr_v6[0] = utx->ut_addr_v6[3]; utx->ut_addr_v6[1] = 0; utx->ut_addr_v6[2] = 0; utx->ut_addr_v6[3] = 0; } } # endif # ifdef HAVE_SYSLEN_IN_UTMPX /* ut_syslen is the length of the utx_host string */ utx->ut_syslen = MINIMUM(strlen(li->hostname), sizeof(utx->ut_host)); # endif } #endif /* USE_UTMPX || USE_WTMPX */ /** ** Low-level utmp functions **/ /* FIXME: (ATL) utmp_write_direct needs testing */ #ifdef USE_UTMP /* if we can, use pututline() etc. */ # if !defined(DISABLE_PUTUTLINE) && defined(HAVE_SETUTENT) && \ defined(HAVE_PUTUTLINE) # define UTMP_USE_LIBRARY # endif /* write a utmp entry with the system's help (pututline() and pals) */ # ifdef UTMP_USE_LIBRARY static int utmp_write_library(struct logininfo *li, struct utmp *ut) { setutent(); pututline(ut); # ifdef HAVE_ENDUTENT endutent(); # endif return (1); } # else /* UTMP_USE_LIBRARY */ /* * Write a utmp entry direct to the file * This is a slightly modification of code in OpenBSD's login.c */ static int utmp_write_direct(struct logininfo *li, struct utmp *ut) { struct utmp old_ut; register int fd; int tty; /* FIXME: (ATL) ttyslot() needs local implementation */ #if defined(HAVE_GETTTYENT) struct ttyent *ty; tty=0; setttyent(); while (NULL != (ty = getttyent())) { tty++; if (!strncmp(ty->ty_name, ut->ut_line, sizeof(ut->ut_line))) break; } endttyent(); if (NULL == ty) { logit("%s: tty not found", __func__); return (0); } #else /* FIXME */ tty = ttyslot(); /* seems only to work for /dev/ttyp? style names */ #endif /* HAVE_GETTTYENT */ if (tty > 0 && (fd = open(UTMP_FILE, O_RDWR|O_CREAT, 0644)) >= 0) { off_t pos, ret; pos = (off_t)tty * sizeof(struct utmp); if ((ret = lseek(fd, pos, SEEK_SET)) == -1) { logit("%s: lseek: %s", __func__, strerror(errno)); close(fd); return (0); } if (ret != pos) { logit("%s: Couldn't seek to tty %d slot in %s", __func__, tty, UTMP_FILE); close(fd); return (0); } /* * Prevent luser from zero'ing out ut_host. * If the new ut_line is empty but the old one is not * and ut_line and ut_name match, preserve the old ut_line. */ if (atomicio(read, fd, &old_ut, sizeof(old_ut)) == sizeof(old_ut) && (ut->ut_host[0] == '\0') && (old_ut.ut_host[0] != '\0') && (strncmp(old_ut.ut_line, ut->ut_line, sizeof(ut->ut_line)) == 0) && (strncmp(old_ut.ut_name, ut->ut_name, sizeof(ut->ut_name)) == 0)) memcpy(ut->ut_host, old_ut.ut_host, sizeof(ut->ut_host)); if ((ret = lseek(fd, pos, SEEK_SET)) == -1) { logit("%s: lseek: %s", __func__, strerror(errno)); close(fd); return (0); } if (ret != pos) { logit("%s: Couldn't seek to tty %d slot in %s", __func__, tty, UTMP_FILE); close(fd); return (0); } if (atomicio(vwrite, fd, ut, sizeof(*ut)) != sizeof(*ut)) { logit("%s: error writing %s: %s", __func__, UTMP_FILE, strerror(errno)); close(fd); return (0); } close(fd); return (1); } else { return (0); } } # endif /* UTMP_USE_LIBRARY */ static int utmp_perform_login(struct logininfo *li) { struct utmp ut; construct_utmp(li, &ut); # ifdef UTMP_USE_LIBRARY if (!utmp_write_library(li, &ut)) { logit("%s: utmp_write_library() failed", __func__); return (0); } # else if (!utmp_write_direct(li, &ut)) { logit("%s: utmp_write_direct() failed", __func__); return (0); } # endif return (1); } static int utmp_perform_logout(struct logininfo *li) { struct utmp ut; construct_utmp(li, &ut); # ifdef UTMP_USE_LIBRARY if (!utmp_write_library(li, &ut)) { logit("%s: utmp_write_library() failed", __func__); return (0); } # else if (!utmp_write_direct(li, &ut)) { logit("%s: utmp_write_direct() failed", __func__); return (0); } # endif return (1); } int utmp_write_entry(struct logininfo *li) { switch(li->type) { case LTYPE_LOGIN: return (utmp_perform_login(li)); case LTYPE_LOGOUT: return (utmp_perform_logout(li)); default: logit("%s: invalid type field", __func__); return (0); } } #endif /* USE_UTMP */ /** ** Low-level utmpx functions **/ /* not much point if we don't want utmpx entries */ #ifdef USE_UTMPX /* if we have the wherewithall, use pututxline etc. */ # if !defined(DISABLE_PUTUTXLINE) && defined(HAVE_SETUTXENT) && \ defined(HAVE_PUTUTXLINE) # define UTMPX_USE_LIBRARY # endif /* write a utmpx entry with the system's help (pututxline() and pals) */ # ifdef UTMPX_USE_LIBRARY static int utmpx_write_library(struct logininfo *li, struct utmpx *utx) { setutxent(); pututxline(utx); # ifdef HAVE_ENDUTXENT endutxent(); # endif return (1); } # else /* UTMPX_USE_LIBRARY */ /* write a utmp entry direct to the file */ static int utmpx_write_direct(struct logininfo *li, struct utmpx *utx) { logit("%s: not implemented!", __func__); return (0); } # endif /* UTMPX_USE_LIBRARY */ static int utmpx_perform_login(struct logininfo *li) { struct utmpx utx; construct_utmpx(li, &utx); # ifdef UTMPX_USE_LIBRARY if (!utmpx_write_library(li, &utx)) { logit("%s: utmp_write_library() failed", __func__); return (0); } # else if (!utmpx_write_direct(li, &ut)) { logit("%s: utmp_write_direct() failed", __func__); return (0); } # endif return (1); } static int utmpx_perform_logout(struct logininfo *li) { struct utmpx utx; construct_utmpx(li, &utx); # ifdef HAVE_ID_IN_UTMPX line_abbrevname(utx.ut_id, li->line, sizeof(utx.ut_id)); # endif # ifdef HAVE_TYPE_IN_UTMPX utx.ut_type = DEAD_PROCESS; # endif # ifdef UTMPX_USE_LIBRARY utmpx_write_library(li, &utx); # else utmpx_write_direct(li, &utx); # endif return (1); } int utmpx_write_entry(struct logininfo *li) { switch(li->type) { case LTYPE_LOGIN: return (utmpx_perform_login(li)); case LTYPE_LOGOUT: return (utmpx_perform_logout(li)); default: logit("%s: invalid type field", __func__); return (0); } } #endif /* USE_UTMPX */ /** ** Low-level wtmp functions **/ #ifdef USE_WTMP /* * Write a wtmp entry direct to the end of the file * This is a slight modification of code in OpenBSD's logwtmp.c */ static int wtmp_write(struct logininfo *li, struct utmp *ut) { struct stat buf; int fd, ret = 1; if ((fd = open(WTMP_FILE, O_WRONLY|O_APPEND, 0)) < 0) { logit("%s: problem writing %s: %s", __func__, WTMP_FILE, strerror(errno)); return (0); } if (fstat(fd, &buf) == 0) if (atomicio(vwrite, fd, ut, sizeof(*ut)) != sizeof(*ut)) { ftruncate(fd, buf.st_size); logit("%s: problem writing %s: %s", __func__, WTMP_FILE, strerror(errno)); ret = 0; } close(fd); return (ret); } static int wtmp_perform_login(struct logininfo *li) { struct utmp ut; construct_utmp(li, &ut); return (wtmp_write(li, &ut)); } static int wtmp_perform_logout(struct logininfo *li) { struct utmp ut; construct_utmp(li, &ut); return (wtmp_write(li, &ut)); } int wtmp_write_entry(struct logininfo *li) { switch(li->type) { case LTYPE_LOGIN: return (wtmp_perform_login(li)); case LTYPE_LOGOUT: return (wtmp_perform_logout(li)); default: logit("%s: invalid type field", __func__); return (0); } } /* * Notes on fetching login data from wtmp/wtmpx * * Logouts are usually recorded with (amongst other things) a blank * username on a given tty line. However, some systems (HP-UX is one) * leave all fields set, but change the ut_type field to DEAD_PROCESS. * * Since we're only looking for logins here, we know that the username * must be set correctly. On systems that leave it in, we check for * ut_type==USER_PROCESS (indicating a login.) * * Portability: Some systems may set something other than USER_PROCESS * to indicate a login process. I don't know of any as I write. Also, * it's possible that some systems may both leave the username in * place and not have ut_type. */ /* return true if this wtmp entry indicates a login */ static int wtmp_islogin(struct logininfo *li, struct utmp *ut) { if (strncmp(li->username, ut->ut_name, MIN_SIZEOF(li->username, ut->ut_name)) == 0) { # ifdef HAVE_TYPE_IN_UTMP if (ut->ut_type & USER_PROCESS) return (1); # else return (1); # endif } return (0); } int wtmp_get_entry(struct logininfo *li) { struct stat st; struct utmp ut; int fd, found = 0; /* Clear the time entries in our logininfo */ li->tv_sec = li->tv_usec = 0; if ((fd = open(WTMP_FILE, O_RDONLY)) < 0) { logit("%s: problem opening %s: %s", __func__, WTMP_FILE, strerror(errno)); return (0); } if (fstat(fd, &st) != 0) { logit("%s: couldn't stat %s: %s", __func__, WTMP_FILE, strerror(errno)); close(fd); return (0); } /* Seek to the start of the last struct utmp */ if (lseek(fd, -(off_t)sizeof(struct utmp), SEEK_END) == -1) { /* Looks like we've got a fresh wtmp file */ close(fd); return (0); } while (!found) { if (atomicio(read, fd, &ut, sizeof(ut)) != sizeof(ut)) { logit("%s: read of %s failed: %s", __func__, WTMP_FILE, strerror(errno)); close (fd); return (0); } if (wtmp_islogin(li, &ut) ) { found = 1; /* * We've already checked for a time in struct * utmp, in login_getlast() */ # ifdef HAVE_TIME_IN_UTMP li->tv_sec = ut.ut_time; # else # if HAVE_TV_IN_UTMP li->tv_sec = ut.ut_tv.tv_sec; # endif # endif line_fullname(li->line, ut.ut_line, MIN_SIZEOF(li->line, ut.ut_line)); # ifdef HAVE_HOST_IN_UTMP strlcpy(li->hostname, ut.ut_host, MIN_SIZEOF(li->hostname, ut.ut_host)); # endif continue; } /* Seek back 2 x struct utmp */ if (lseek(fd, -(off_t)(2 * sizeof(struct utmp)), SEEK_CUR) == -1) { /* We've found the start of the file, so quit */ close(fd); return (0); } } /* We found an entry. Tidy up and return */ close(fd); return (1); } # endif /* USE_WTMP */ /** ** Low-level wtmpx functions **/ #ifdef USE_WTMPX /* * Write a wtmpx entry direct to the end of the file * This is a slight modification of code in OpenBSD's logwtmp.c */ static int wtmpx_write(struct logininfo *li, struct utmpx *utx) { #ifndef HAVE_UPDWTMPX struct stat buf; int fd, ret = 1; if ((fd = open(WTMPX_FILE, O_WRONLY|O_APPEND, 0)) < 0) { logit("%s: problem opening %s: %s", __func__, WTMPX_FILE, strerror(errno)); return (0); } if (fstat(fd, &buf) == 0) if (atomicio(vwrite, fd, utx, sizeof(*utx)) != sizeof(*utx)) { ftruncate(fd, buf.st_size); logit("%s: problem writing %s: %s", __func__, WTMPX_FILE, strerror(errno)); ret = 0; } close(fd); return (ret); #else updwtmpx(WTMPX_FILE, utx); return (1); #endif } static int wtmpx_perform_login(struct logininfo *li) { struct utmpx utx; construct_utmpx(li, &utx); return (wtmpx_write(li, &utx)); } static int wtmpx_perform_logout(struct logininfo *li) { struct utmpx utx; construct_utmpx(li, &utx); return (wtmpx_write(li, &utx)); } int wtmpx_write_entry(struct logininfo *li) { switch(li->type) { case LTYPE_LOGIN: return (wtmpx_perform_login(li)); case LTYPE_LOGOUT: return (wtmpx_perform_logout(li)); default: logit("%s: invalid type field", __func__); return (0); } } /* Please see the notes above wtmp_islogin() for information about the next two functions */ /* Return true if this wtmpx entry indicates a login */ static int wtmpx_islogin(struct logininfo *li, struct utmpx *utx) { if (strncmp(li->username, utx->ut_user, MIN_SIZEOF(li->username, utx->ut_user)) == 0 ) { # ifdef HAVE_TYPE_IN_UTMPX if (utx->ut_type == USER_PROCESS) return (1); # else return (1); # endif } return (0); } int wtmpx_get_entry(struct logininfo *li) { struct stat st; struct utmpx utx; int fd, found=0; /* Clear the time entries */ li->tv_sec = li->tv_usec = 0; if ((fd = open(WTMPX_FILE, O_RDONLY)) < 0) { logit("%s: problem opening %s: %s", __func__, WTMPX_FILE, strerror(errno)); return (0); } if (fstat(fd, &st) != 0) { logit("%s: couldn't stat %s: %s", __func__, WTMPX_FILE, strerror(errno)); close(fd); return (0); } /* Seek to the start of the last struct utmpx */ if (lseek(fd, -(off_t)sizeof(struct utmpx), SEEK_END) == -1 ) { /* probably a newly rotated wtmpx file */ close(fd); return (0); } while (!found) { if (atomicio(read, fd, &utx, sizeof(utx)) != sizeof(utx)) { logit("%s: read of %s failed: %s", __func__, WTMPX_FILE, strerror(errno)); close (fd); return (0); } /* * Logouts are recorded as a blank username on a particular * line. So, we just need to find the username in struct utmpx */ if (wtmpx_islogin(li, &utx)) { found = 1; # if defined(HAVE_TV_IN_UTMPX) li->tv_sec = utx.ut_tv.tv_sec; # elif defined(HAVE_TIME_IN_UTMPX) li->tv_sec = utx.ut_time; # endif line_fullname(li->line, utx.ut_line, sizeof(li->line)); # if defined(HAVE_HOST_IN_UTMPX) strlcpy(li->hostname, utx.ut_host, MIN_SIZEOF(li->hostname, utx.ut_host)); # endif continue; } if (lseek(fd, -(off_t)(2 * sizeof(struct utmpx)), SEEK_CUR) == -1) { close(fd); return (0); } } close(fd); return (1); } #endif /* USE_WTMPX */ /** ** Low-level libutil login() functions **/ #ifdef USE_LOGIN static int syslogin_perform_login(struct logininfo *li) { struct utmp *ut; ut = xmalloc(sizeof(*ut)); construct_utmp(li, ut); login(ut); free(ut); return (1); } static int syslogin_perform_logout(struct logininfo *li) { # ifdef HAVE_LOGOUT char line[UT_LINESIZE]; (void)line_stripname(line, li->line, sizeof(line)); if (!logout(line)) logit("%s: logout() returned an error", __func__); # ifdef HAVE_LOGWTMP else logwtmp(line, "", ""); # endif /* FIXME: (ATL - if the need arises) What to do if we have * login, but no logout? what if logout but no logwtmp? All * routines are in libutil so they should all be there, * but... */ # endif return (1); } int syslogin_write_entry(struct logininfo *li) { switch (li->type) { case LTYPE_LOGIN: return (syslogin_perform_login(li)); case LTYPE_LOGOUT: return (syslogin_perform_logout(li)); default: logit("%s: Invalid type field", __func__); return (0); } } #endif /* USE_LOGIN */ /* end of file log-syslogin.c */ /** ** Low-level lastlog functions **/ #ifdef USE_LASTLOG #if !defined(LASTLOG_WRITE_PUTUTXLINE) || !defined(HAVE_GETLASTLOGXBYNAME) /* open the file (using filemode) and seek to the login entry */ static int lastlog_openseek(struct logininfo *li, int *fd, int filemode) { off_t offset; char lastlog_file[1024]; struct stat st; if (stat(LASTLOG_FILE, &st) != 0) { logit("%s: Couldn't stat %s: %s", __func__, LASTLOG_FILE, strerror(errno)); return (0); } if (S_ISDIR(st.st_mode)) { snprintf(lastlog_file, sizeof(lastlog_file), "%s/%s", LASTLOG_FILE, li->username); } else if (S_ISREG(st.st_mode)) { strlcpy(lastlog_file, LASTLOG_FILE, sizeof(lastlog_file)); } else { logit("%s: %.100s is not a file or directory!", __func__, LASTLOG_FILE); return (0); } *fd = open(lastlog_file, filemode, 0600); if (*fd < 0) { debug("%s: Couldn't open %s: %s", __func__, lastlog_file, strerror(errno)); return (0); } if (S_ISREG(st.st_mode)) { /* find this uid's offset in the lastlog file */ offset = (off_t) ((u_long)li->uid * sizeof(struct lastlog)); if (lseek(*fd, offset, SEEK_SET) != offset) { logit("%s: %s->lseek(): %s", __func__, lastlog_file, strerror(errno)); close(*fd); return (0); } } return (1); } #endif /* !LASTLOG_WRITE_PUTUTXLINE || !HAVE_GETLASTLOGXBYNAME */ #ifdef LASTLOG_WRITE_PUTUTXLINE int lastlog_write_entry(struct logininfo *li) { switch(li->type) { case LTYPE_LOGIN: return 1; /* lastlog written by pututxline */ default: logit("lastlog_write_entry: Invalid type field"); return 0; } } #else /* LASTLOG_WRITE_PUTUTXLINE */ int lastlog_write_entry(struct logininfo *li) { struct lastlog last; int fd; switch(li->type) { case LTYPE_LOGIN: /* create our struct lastlog */ memset(&last, '\0', sizeof(last)); line_stripname(last.ll_line, li->line, sizeof(last.ll_line)); strlcpy(last.ll_host, li->hostname, MIN_SIZEOF(last.ll_host, li->hostname)); last.ll_time = li->tv_sec; if (!lastlog_openseek(li, &fd, O_RDWR|O_CREAT)) return (0); /* write the entry */ if (atomicio(vwrite, fd, &last, sizeof(last)) != sizeof(last)) { close(fd); logit("%s: Error writing to %s: %s", __func__, LASTLOG_FILE, strerror(errno)); return (0); } close(fd); return (1); default: logit("%s: Invalid type field", __func__); return (0); } } #endif /* LASTLOG_WRITE_PUTUTXLINE */ #ifdef HAVE_GETLASTLOGXBYNAME int lastlog_get_entry(struct logininfo *li) { struct lastlogx l, *ll; if ((ll = getlastlogxbyname(li->username, &l)) == NULL) { memset(&l, '\0', sizeof(l)); ll = &l; } line_fullname(li->line, ll->ll_line, sizeof(li->line)); strlcpy(li->hostname, ll->ll_host, MIN_SIZEOF(li->hostname, ll->ll_host)); li->tv_sec = ll->ll_tv.tv_sec; li->tv_usec = ll->ll_tv.tv_usec; return (1); } #else /* HAVE_GETLASTLOGXBYNAME */ int lastlog_get_entry(struct logininfo *li) { struct lastlog last; int fd, ret; if (!lastlog_openseek(li, &fd, O_RDONLY)) return (0); ret = atomicio(read, fd, &last, sizeof(last)); close(fd); switch (ret) { case 0: memset(&last, '\0', sizeof(last)); /* FALLTHRU */ case sizeof(last): line_fullname(li->line, last.ll_line, sizeof(li->line)); strlcpy(li->hostname, last.ll_host, MIN_SIZEOF(li->hostname, last.ll_host)); li->tv_sec = last.ll_time; return (1); case -1: error("%s: Error reading from %s: %s", __func__, LASTLOG_FILE, strerror(errno)); return (0); default: error("%s: Error reading from %s: Expecting %d, got %d", __func__, LASTLOG_FILE, (int)sizeof(last), ret); return (0); } /* NOTREACHED */ return (0); } #endif /* HAVE_GETLASTLOGXBYNAME */ #endif /* USE_LASTLOG */ #if defined(USE_UTMPX) && defined(HAVE_SETUTXDB) && \ defined(UTXDB_LASTLOGIN) && defined(HAVE_GETUTXUSER) int utmpx_get_entry(struct logininfo *li) { struct utmpx *utx; if (setutxdb(UTXDB_LASTLOGIN, NULL) != 0) return (0); utx = getutxuser(li->username); if (utx == NULL) { endutxent(); return (0); } line_fullname(li->line, utx->ut_line, MIN_SIZEOF(li->line, utx->ut_line)); strlcpy(li->hostname, utx->ut_host, MIN_SIZEOF(li->hostname, utx->ut_host)); li->tv_sec = utx->ut_tv.tv_sec; li->tv_usec = utx->ut_tv.tv_usec; endutxent(); return (1); } #endif /* USE_UTMPX && HAVE_SETUTXDB && UTXDB_LASTLOGIN && HAVE_GETUTXUSER */ #ifdef USE_BTMP /* * Logs failed login attempts in _PATH_BTMP if that exists. * The most common login failure is to give password instead of username. * So the _PATH_BTMP file checked for the correct permission, so that only * root can read it. */ void record_failed_login(struct ssh *ssh, const char *username, const char *hostname, const char *ttyn) { int fd; struct utmp ut; struct logininfo li; socklen_t fromlen = sizeof(li.hostaddr); time_t t; struct stat fst; if (geteuid() != 0) return; if ((fd = open(_PATH_BTMP, O_WRONLY | O_APPEND)) < 0) { debug("Unable to open the btmp file %s: %s", _PATH_BTMP, strerror(errno)); return; } if (fstat(fd, &fst) < 0) { logit("%s: fstat of %s failed: %s", __func__, _PATH_BTMP, strerror(errno)); goto out; } if ((fst.st_mode & (S_IXGRP | S_IRWXO)) || fst.st_uid != 0) { logit("Excess permission or bad ownership on file %s", _PATH_BTMP); goto out; } /* Construct a logininfo and turn it into a utmp */ memset(&li, 0, sizeof(li)); li.type = LTYPE_LOGIN; li.pid = getpid(); strlcpy(li.line, "ssh:notty", sizeof(li.line)); strlcpy(li.username, username, sizeof(li.username)); strlcpy(li.hostname, hostname, sizeof(li.hostname)); time(&t); li.tv_sec = t > 0 ? (unsigned long)t : 0; if (ssh_packet_connection_is_on_socket(ssh)) { (void)getpeername(ssh_packet_get_connection_in(ssh), &li.hostaddr.sa, &fromlen); } construct_utmp(&li, &ut); if (atomicio(vwrite, fd, &ut, sizeof(ut)) != sizeof(ut)) { error("Failed to write to %s: %s", _PATH_BTMP, strerror(errno)); } out: close(fd); } #endif /* USE_BTMP */