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Diffstat (limited to 'src/loginrec.c')
| -rw-r--r-- | src/loginrec.c | 1380 |
1 files changed, 1380 insertions, 0 deletions
diff --git a/src/loginrec.c b/src/loginrec.c new file mode 100644 index 0000000..b543bcb --- /dev/null +++ b/src/loginrec.c @@ -0,0 +1,1380 @@ +/* + * 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 + **/ + +/* For now lastlog code has been removed as it wasn't being used by Dropbear. */ + +/* + 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_<method> or CONF_<method>_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! + +*/ + +/** + ** TODO: + ** homegrown ttyslot() + ** test, test, test + ** + ** Platform status: + ** ---------------- + ** + ** Known good: + ** Linux (Redhat 6.2, Debian) + ** Solaris + ** HP-UX 10.20 (gcc only) + ** IRIX + ** NeXT - M68k/HPPA/Sparc (4.2/3.3) + ** + ** Testing required: Please send reports! + ** NetBSD + ** HP-UX 11 + ** AIX + ** + ** Platforms with known problems: + ** Some variants of Slackware Linux + ** + **/ + + +#include "includes.h" +#include "loginrec.h" +#include "dbutil.h" +#include "atomicio.h" + +/** + ** 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 wtmp_get_entry(struct logininfo *li); +int wtmpx_get_entry(struct logininfo *li); + +/* 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_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(int pid, const char *username, + const char *hostname, const char *line) +{ + struct logininfo *newli; + + newli = (struct logininfo *) m_malloc (sizeof(*newli)); + (void)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) +{ + m_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, int 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) + dropbear_exit("login_init_entry: Cannot find user \"%s\"", + 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; +} + +/** + ** login_write: Call low-level recording functions based on autoconf + ** results + **/ +int +login_write (struct logininfo *li) +{ +#ifndef HAVE_CYGWIN + if ((int)geteuid() != 0) { + 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 + 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 + + + +/* + * '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, size_t 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, size_t 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 <dstsize> characters of the + * full name.) + * + * NOTE: use strncpy because we do NOT necessarily want zero + * termination */ +char * +line_abbrevname(char *dst, const char *src, size_t dstsize) +{ + size_t len; + + memset(dst, '\0', dstsize); + + /* 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) +{ + /* struct utmp in glibc isn't y2038 safe yet */ +# ifdef HAVE_STRUCT_UTMP_UT_TV + ut->ut_tv.tv_sec = li->tv_sec; + ut->ut_tv.tv_usec = li->tv_usec; +# else +# ifdef HAVE_STRUCT_UTMP_UT_TIME + ut->ut_time = li->tv_sec; +# endif +# 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_STRUCT_UTMP_UT_ID + line_abbrevname(ut->ut_id, li->line, sizeof(ut->ut_id)); +# endif + +# ifdef HAVE_STRUCT_UTMP_UT_TYPE + /* This is done here to keep utmp constants out of struct logininfo */ + switch (li->type) { + case LTYPE_LOGIN: + ut->ut_type = USER_PROCESS; +#ifdef _UNICOS + cray_set_tmpdir(ut); +#endif + break; + case LTYPE_LOGOUT: + ut->ut_type = DEAD_PROCESS; +#ifdef _UNICOS + cray_retain_utmp(ut, li->pid); +#endif + break; + } +# endif + set_utmp_time(li, ut); + + line_stripname(ut->ut_line, li->line, sizeof(ut->ut_line)); + +# ifdef HAVE_STRUCT_UTMP_UT_PID + 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_STRUCT_UTMP_UT_HOST + strncpy(ut->ut_host, li->hostname, MIN_SIZEOF(ut->ut_host, li->hostname)); +# endif +# ifdef HAVE_STRUCT_UTMP_UT_ADDR + /* 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) +{ +# ifdef HAVE_STRUCT_UTMPX_UT_TV + utx->ut_tv.tv_sec = li->tv_sec; + utx->ut_tv.tv_usec = li->tv_usec; +# else /* HAVE_STRUCT_UTMPX_UT_TV */ +# ifdef HAVE_STRUCT_UTMPX_UT_TIME + utx->ut_time = li->tv_sec; +# endif /* HAVE_STRUCT_UTMPX_UT_TIME */ +# endif /* HAVE_STRUCT_UTMPX_UT_TV */ +} + +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_STRUCT_UTMPX_UT_ID + 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_name, li->username, MIN_SIZEOF(utx->ut_name, li->username)); + + if (li->type == LTYPE_LOGOUT) + return; + + /* + * These fields are only used when logging in, and are blank + * for logouts. + */ + +# ifdef HAVE_STRUCT_UTMPX_UT_HOST + strncpy(utx->ut_host, li->hostname, MIN_SIZEOF(utx->ut_host, li->hostname)); +# endif +# ifdef HAVE_STRUCT_UTMPX_UT_ADDR + /* 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(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 +# ifdef HAVE_STRUCT_UTMPX_UT_SYSLEN + /* ut_syslen is the length of the utx_host string */ + utx->ut_syslen = MIN(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) + register struct ttyent *ty; + + tty=0; + + setttyent(); + while ((struct ttyent *)0 != (ty = getttyent())) { + tty++; + if (!strncmp(ty->ty_name, ut->ut_line, sizeof(ut->ut_line))) + break; + } + endttyent(); + + if((struct ttyent *)0 == ty) { + dropbear_log(LOG_WARNING, "utmp_write_entry: tty not found"); + return(1); + } +#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) { + (void)lseek(fd, (off_t)(tty * sizeof(struct utmp)), SEEK_SET); + /* + * 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)) { + (void)memcpy(ut->ut_host, old_ut.ut_host, sizeof(ut->ut_host)); + } + + (void)lseek(fd, (off_t)(tty * sizeof(struct utmp)), SEEK_SET); + if (atomicio(vwrite, fd, ut, sizeof(*ut)) != sizeof(*ut)) + dropbear_log(LOG_WARNING, "utmp_write_direct: error writing %s: %s", + UTMP_FILE, strerror(errno)); + + (void)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)) { + dropbear_log(LOG_WARNING, "utmp_perform_login: utmp_write_library() failed"); + return 0; + } +# else + if (!utmp_write_direct(li, &ut)) { + dropbear_log(LOG_WARNING, "utmp_perform_login: utmp_write_direct() failed"); + 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)) { + dropbear_log(LOG_WARNING, "utmp_perform_logout: utmp_write_library() failed"); + return 0; + } +# else + if (!utmp_write_direct(li, &ut)) { + dropbear_log(LOG_WARNING, "utmp_perform_logout: utmp_write_direct() failed"); + 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: + dropbear_log(LOG_WARNING, "utmp_write_entry: invalid type field"); + 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) +{ + dropbear_log(LOG_WARNING, "utmpx_write_direct: not implemented!"); + 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)) { + dropbear_log(LOG_WARNING, "utmpx_perform_login: utmp_write_library() failed"); + return 0; + } +# else + if (!utmpx_write_direct(li, &utx)) { + dropbear_log(LOG_WARNING, "utmpx_perform_login: utmp_write_direct() failed"); + return 0; + } +# endif + return 1; +} + + +static int +utmpx_perform_logout(struct logininfo *li) +{ + struct utmpx utx; + + construct_utmpx(li, &utx); +# ifdef HAVE_STRUCT_UTMPX_UT_ID + line_abbrevname(utx.ut_id, li->line, sizeof(utx.ut_id)); +# endif +# ifdef HAVE_STRUCT_UTMPX_UT_TYPE + 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: + dropbear_log(LOG_WARNING, "utmpx_write_entry: invalid type field"); + 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) { + dropbear_log(LOG_WARNING, "wtmp_write: problem writing %s: %s", + 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); + dropbear_log(LOG_WARNING, "wtmp_write: problem writing %s: %s", + WTMP_FILE, strerror(errno)); + ret = 0; + } + (void)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: + dropbear_log(LOG_WARNING, "wtmp_write_entry: invalid type field"); + 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_STRUCT_UTMP_UT_TYPE + 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) { + dropbear_log(LOG_WARNING, "wtmp_get_entry: problem opening %s: %s", + WTMP_FILE, strerror(errno)); + return 0; + } + if (fstat(fd, &st) != 0) { + dropbear_log(LOG_WARNING, "wtmp_get_entry: couldn't stat %s: %s", + 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)) { + dropbear_log(LOG_WARNING, "wtmp_get_entry: read of %s failed: %s", + 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_STRUCT_UTMP_UT_TIME + li->tv_sec = ut.ut_time; +# else +# if HAVE_STRUCT_UTMP_UT_TV + 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_STRUCT_UTMP_UT_HOST + 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) +{ + struct stat buf; + int fd, ret = 1; + + if ((fd = open(WTMPX_FILE, O_WRONLY|O_APPEND, 0)) < 0) { + dropbear_log(LOG_WARNING, "wtmpx_write: problem opening %s: %s", + 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); + dropbear_log(LOG_WARNING, "wtmpx_write: problem writing %s: %s", + WTMPX_FILE, strerror(errno)); + ret = 0; + } + (void)close(fd); + + return ret; +} + + +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: + dropbear_log(LOG_WARNING, "wtmpx_write_entry: invalid type field"); + 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_name, + MIN_SIZEOF(li->username, utx->ut_name)) == 0 ) { +# ifdef HAVE_STRUCT_UTMPX_UT_TYPE + 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) { + dropbear_log(LOG_WARNING, "wtmpx_get_entry: problem opening %s: %s", + WTMPX_FILE, strerror(errno)); + return 0; + } + if (fstat(fd, &st) != 0) { + dropbear_log(LOG_WARNING, "wtmpx_get_entry: couldn't stat %s: %s", + 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)) { + dropbear_log(LOG_WARNING, "wtmpx_get_entry: read of %s failed: %s", + 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; +# ifdef HAVE_STRUCT_UTMPX_UT_TV + li->tv_sec = utx.ut_tv.tv_sec; +# else +# ifdef HAVE_STRUCT_UTMPX_UT_TIME + li->tv_sec = utx.ut_time; +# endif +# endif + line_fullname(li->line, utx.ut_line, sizeof(li->line)); +# ifdef HAVE_STRUCT_UTMPX_UT_HOST + 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; + + if (! (ut = (struct utmp *)malloc(sizeof(*ut)))) { + dropbear_log(LOG_WARNING, "syslogin_perform_login: couldn't malloc()"); + return 0; + } + construct_utmp(li, ut); + login(ut); + free(ut); + + return 1; +} + +static int +syslogin_perform_logout(struct logininfo *li) +{ +# ifdef HAVE_LOGOUT + char line[8]; + + (void)line_stripname(line, li->line, sizeof(line)); + + if (!logout(line)) { + dropbear_log(LOG_WARNING, "syslogin_perform_logout: logout(%s) returned an error: %s", line, strerror(errno)); +# 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: + dropbear_log(LOG_WARNING, "syslogin_write_entry: Invalid type field"); + return 0; + } +} +#endif /* USE_LOGIN */ + +/* end of file log-syslogin.c */ + +/** + ** Low-level lastlog functions + **/ + +#ifdef USE_LASTLOG +#define LL_FILE 1 +#define LL_DIR 2 +#define LL_OTHER 3 + +static void +lastlog_construct(struct logininfo *li, struct lastlog *last) +{ + /* clear the structure */ + memset(last, '\0', sizeof(*last)); + + (void)line_stripname(last->ll_line, li->line, sizeof(last->ll_line)); + strlcpy(last->ll_host, li->hostname, + MIN_SIZEOF(last->ll_host, li->hostname)); + /* struct lastlog in glibc isn't y2038 safe yet */ + last->ll_time = li->tv_sec; +} + +static int +lastlog_filetype(char *filename) +{ + struct stat st; + + if (stat(filename, &st) != 0) { + dropbear_log(LOG_WARNING, "lastlog_perform_login: Couldn't stat %s: %s", filename, + strerror(errno)); + return 0; + } + if (S_ISDIR(st.st_mode)) + return LL_DIR; + else if (S_ISREG(st.st_mode)) + return LL_FILE; + else + return LL_OTHER; +} + + +/* 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; + int type; + char lastlog_file[1024]; + + type = lastlog_filetype(LASTLOG_FILE); + switch (type) { + case LL_FILE: + strlcpy(lastlog_file, LASTLOG_FILE, sizeof(lastlog_file)); + break; + case LL_DIR: + snprintf(lastlog_file, sizeof(lastlog_file), "%s/%s", + LASTLOG_FILE, li->username); + break; + default: + dropbear_log(LOG_WARNING, "lastlog_openseek: %.100s is not a file or directory!", + LASTLOG_FILE); + return 0; + } + + *fd = open(lastlog_file, filemode, 0600); + if ( *fd < 0) { + dropbear_log(LOG_INFO, "lastlog_openseek: Couldn't open %s: %s", + lastlog_file, strerror(errno)); + return 0; + } + + if (type == LL_FILE) { + /* find this uid's offset in the lastlog file */ + offset = (off_t) ((long)li->uid * sizeof(struct lastlog)); + + if ( lseek(*fd, offset, SEEK_SET) != offset ) { + dropbear_log(LOG_WARNING, "lastlog_openseek: %s->lseek(): %s", + lastlog_file, strerror(errno)); + m_close(*fd); + return 0; + } + } + + return 1; +} + +static int +lastlog_perform_login(struct logininfo *li) +{ + struct lastlog last; + int fd; + + /* create our struct lastlog */ + lastlog_construct(li, &last); + + 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); + dropbear_log(LOG_WARNING, "lastlog_write_filemode: Error writing to %s: %s", + LASTLOG_FILE, strerror(errno)); + return 0; + } + + close(fd); + return 1; +} + +int +lastlog_write_entry(struct logininfo *li) +{ + switch(li->type) { + case LTYPE_LOGIN: + return lastlog_perform_login(li); + default: + dropbear_log(LOG_WARNING, "lastlog_write_entry: Invalid type field"); + return 0; + } +} + +#endif /* USE_LASTLOG */ |