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procps/w.c
Qualys Security Advisory eaec2d0977 0121-w: Clamp maxcmd to the MIN/MAX_CMD_WIDTH range. 
The current checks allow out-of-range values (for example, if
getenv/atoi returns ~-2GB, maxcmd becomes ~+2GB after the subtraction).
This is not a security problem, none of this is under an attacker's
control.
2018-06-23 21:59:14 +10:00

682 lines
19 KiB
C
Raw Blame History

/*
* w - show what logged in users are doing.
*
* Almost entirely rewritten from scratch by Charles Blake circa
* June 1996. Some vestigal traces of the original may exist.
* That was done in 1993 by Larry Greenfield with some fixes by
* Michael K. Johnson.
*
* Changes by Albert Cahalan, 2002.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "c.h"
#include "fileutils.h"
#include "nls.h"
#include <proc/procps.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <limits.h>
#include <locale.h>
#include <locale.h>
#include <pwd.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <termios.h>
#include <time.h>
#include <unistd.h>
#include <utmp.h>
#include <arpa/inet.h>
static int ignoreuser = 0; /* for '-u' */
static int oldstyle = 0; /* for '-o' */
typedef struct utmp utmp_t;
#ifdef W_SHOWFROM
# define FROM_STRING "on"
#else
# define FROM_STRING "off"
#endif
#define MAX_CMD_WIDTH 512
#define MIN_CMD_WIDTH 7
/*
* This routine is careful since some programs leave utmp strings
* unprintable. Always outputs at least 16 chars padded with
* spaces on the right if necessary.
*/
static void print_host(const char *restrict host, int len, const int fromlen)
{
const char *last;
int width = 0;
if (len > fromlen)
len = fromlen;
last = host + len;
for (; host < last; host++) {
if (*host == '\0') break;
if (isprint(*host) && *host != ' ') {
fputc(*host, stdout);
++width;
} else {
fputc('-', stdout);
++width;
break;
}
}
/*
* space-fill, and a '-' too if needed to ensure the
* column exists
*/
if (!width) {
fputc('-', stdout);
++width;
}
while (width++ < fromlen)
fputc(' ', stdout);
}
/* This routine prints the display part of the host or IPv6 link address interface */
static void print_display_or_interface(const char *restrict host, int len, int restlen)
{
const char *const end = host + (len > 0 ? len : 0);
const char *disp, *tmp;
if (restlen <= 0) return; /* not enough space for printing anything */
/* search for a collon (might be a display) */
disp = host;
while ( (disp < end) && (*disp != ':') && isprint(*disp) ) disp++;
/* colon found */
if (disp < end && *disp == ':') {
/* detect multiple colons -> IPv6 in the host (not a display) */
tmp = disp+1;
while ( (tmp < end) && (*tmp != ':') && isprint(*tmp) ) tmp++;
if (tmp >= end || *tmp != ':') { /* multiple colons not found - it's a display */
/* number of chars till the end of the input field */
len -= (disp - host);
/* if it is still longer than the rest of the output field, then cut it */
if (len > restlen) len = restlen;
/* print the display */
while ((len > 0) && isprint(*disp) && (*disp != ' ')) {
len--; restlen--;
fputc(*disp, stdout);
disp++;
}
if ((len > 0) && (*disp != '\0')) { /* space or nonprintable found - replace with dash and stop printing */
restlen--;
fputc('-', stdout);
}
} else { /* multiple colons found - it's an IPv6 address */
/* search for % (interface separator in case of IPv6 link address) */
while ( (tmp < end) && (*tmp != '%') && isprint(*tmp) ) tmp++;
if (tmp < end && *tmp == '%') { /* interface separator found */
/* number of chars till the end of the input field */
len -= (tmp - host);
/* if it is still longer than the rest of the output field, then cut it */
if (len > restlen) len = restlen;
/* print the interface */
while ((len > 0) && isprint(*tmp) && (*tmp != ' ')) {
len--; restlen--;
fputc(*tmp, stdout);
tmp++;
}
if ((len > 0) && (*tmp != '\0')) { /* space or nonprintable found - replace with dash and stop printing */
restlen--;
fputc('-', stdout);
}
}
}
}
/* padding with spaces */
while (restlen > 0) {
fputc(' ', stdout);
restlen--;
}
}
/* This routine prints either the hostname or the IP address of the remote */
static void print_from(const utmp_t *restrict const u, const int ip_addresses, const int fromlen) {
char buf[fromlen + 1];
char buf_ipv6[INET6_ADDRSTRLEN];
int len;
#ifndef __CYGWIN__
int32_t ut_addr_v6[4]; /* IP address of the remote host */
if (ip_addresses) { /* -i switch used */
memcpy(&ut_addr_v6, &u->ut_addr_v6, sizeof(ut_addr_v6));
if (IN6_IS_ADDR_V4MAPPED(&ut_addr_v6)) {
/* map back */
ut_addr_v6[0] = ut_addr_v6[3];
ut_addr_v6[1] = 0;
ut_addr_v6[2] = 0;
ut_addr_v6[3] = 0;
}
if (ut_addr_v6[1] || ut_addr_v6[2] || ut_addr_v6[3]) {
/* IPv6 */
if (!inet_ntop(AF_INET6, &ut_addr_v6, buf_ipv6, sizeof(buf_ipv6))) {
strcpy(buf, ""); /* invalid address, clean the buffer */
} else {
strncpy(buf, buf_ipv6, fromlen); /* address valid, copy to buffer */
}
} else {
/* IPv4 */
if (!(ut_addr_v6[0] && inet_ntop(AF_INET, &ut_addr_v6[0], buf, sizeof(buf)))) {
strcpy(buf, ""); /* invalid address, clean the buffer */
}
}
buf[fromlen] = '\0';
len = strlen(buf);
if (len) { /* IP address is non-empty, print it (and concatenate with display, if present) */
fputs(buf, stdout);
/* show the display part of the host or IPv6 link addr. interface, if present */
print_display_or_interface(u->ut_host, UT_HOSTSIZE, fromlen - len);
} else { /* IP address is empty, print the host instead */
print_host(u->ut_host, UT_HOSTSIZE, fromlen);
}
} else { /* -i switch NOT used */
print_host(u->ut_host, UT_HOSTSIZE, fromlen);
}
#else
print_host(u->ut_host, UT_HOSTSIZE, fromlen);
#endif
}
/* compact 7 char format for time intervals (belongs in libproc?) */
static void print_time_ival7(time_t t, int centi_sec, FILE * fout)
{
if ((long)t < (long)0) {
/* system clock changed? */
printf(" ? ");
return;
}
if (oldstyle) {
if (t >= 48 * 60 * 60)
/* > 2 days */
fprintf(fout, _(" %2ludays"), t / (24 * 60 * 60));
else if (t >= 60 * 60)
/* > 1 hour */
/* Translation Hint: Hours:Minutes */
fprintf(fout, " %2lu:%02u ", t / (60 * 60),
(unsigned)((t / 60) % 60));
else if (t > 60)
/* > 1 minute */
/* Translation Hint: Minutes:Seconds */
fprintf(fout, _(" %2lu:%02um"), t / 60, (unsigned)t % 60);
else
fprintf(fout, " ");
} else {
if (t >= 48 * 60 * 60)
/* 2 days or more */
fprintf(fout, _(" %2ludays"), t / (24 * 60 * 60));
else if (t >= 60 * 60)
/* 1 hour or more */
/* Translation Hint: Hours:Minutes */
fprintf(fout, _(" %2lu:%02um"), t / (60 * 60),
(unsigned)((t / 60) % 60));
else if (t > 60)
/* 1 minute or more */
/* Translation Hint: Minutes:Seconds */
fprintf(fout, " %2lu:%02u ", t / 60, (unsigned)t % 60);
else
/* Translation Hint: Seconds:Centiseconds */
fprintf(fout, _(" %2lu.%02us"), t, centi_sec);
}
}
/* stat the device file to get an idle time */
static time_t idletime(const char *restrict const tty)
{
struct stat sbuf;
if (stat(tty, &sbuf) != 0)
return 0;
return time(NULL) - sbuf.st_atime;
}
/* 7 character formatted login time */
static void print_logintime(time_t logt, FILE * fout)
{
/* Abbreviated of weekday can be longer than 3 characters,
* see for instance hu_HU. Using 16 is few bytes more than
* enough. */
char time_str[16];
time_t curt;
struct tm *logtm, *curtm;
int today;
curt = time(NULL);
curtm = localtime(&curt);
/* localtime returns a pointer to static memory */
today = curtm->tm_yday;
logtm = localtime(&logt);
if (curt - logt > 12 * 60 * 60 && logtm->tm_yday != today) {
if (curt - logt > 6 * 24 * 60 * 60) {
strftime(time_str, sizeof(time_str), "%b", logtm);
fprintf(fout, " %02d%3s%02d", logtm->tm_mday,
time_str, logtm->tm_year % 100);
} else {
strftime(time_str, sizeof(time_str), "%a", logtm);
fprintf(fout, " %3s%02d ", time_str,
logtm->tm_hour);
}
} else {
fprintf(fout, " %02d:%02d ", logtm->tm_hour, logtm->tm_min);
}
}
/*
* Get the Device ID of the given TTY
*/
static int get_tty_device(const char *restrict const name)
{
struct stat st;
static char buf[32];
char *dev_paths[] = { "/dev/%s", "/dev/tty%s", "/dev/pts/%s", NULL};
int i;
if (name[0] == '/' && stat(name, &st) == 0)
return st.st_rdev;
for (i=0; dev_paths[i] != NULL; i++) {
snprintf(buf, 32, dev_paths[i], name);
if (stat(buf, &st) == 0)
return st.st_rdev;
}
return -1;
}
/*
* This function scans the process table accumulating total cpu
* times for any processes "associated" with this login session.
* It also searches for the "best" process to report as "(w)hat"
* the user for that login session is doing currently. This the
* essential core of 'w'.
*/
static int find_best_proc(
const utmp_t * restrict const u,
const char *restrict const tty,
unsigned long long *restrict const jcpu,
unsigned long long *restrict const pcpu,
char *cmdline)
{
#define PIDS_GETINT(e) PIDS_VAL(EU_ ## e, s_int, reap->stacks[i], info)
#define PIDS_GETUNT(e) PIDS_VAL(EU_ ## e, u_int, reap->stacks[i], info)
#define PIDS_GETULL(e) PIDS_VAL(EU_ ## e, ull_int, reap->stacks[i], info)
#define PIDS_GETSTR(e) PIDS_VAL(EU_ ## e, str, reap->stacks[i], info)
unsigned uid = ~0U;
int found_utpid = 0;
int i, total_procs, line;
unsigned long long best_time = 0;
unsigned long long secondbest_time = 0;
struct pids_info *info=NULL;
struct pids_fetch *reap;
enum pids_item items[] = {
PIDS_ID_TGID,
PIDS_TIME_START,
PIDS_ID_EUID,
PIDS_ID_RUID,
PIDS_ID_TPGID,
PIDS_ID_PGRP,
PIDS_TTY,
PIDS_TICS_ALL,
PIDS_CMDLINE};
enum rel_items {
EU_TGID, EU_START, EU_EUID, EU_RUID, EU_TPGID, EU_PGRP, EU_TTY,
EU_TICS_ALL, EU_CMDLINE};
*jcpu = 0;
*pcpu = 0;
if (!ignoreuser) {
char buf[UT_NAMESIZE + 1];
struct passwd *passwd_data;
strncpy(buf, u->ut_user, UT_NAMESIZE);
buf[UT_NAMESIZE] = '\0';
if ((passwd_data = getpwnam(buf)) == NULL)
return 0;
uid = passwd_data->pw_uid;
/* OK to have passwd_data go out of scope here */
}
line = get_tty_device(tty);
if (procps_pids_new(&info, items, 9) < 0)
xerrx(EXIT_FAILURE,
_("Unable to create pid info structure"));
if ((reap = procps_pids_reap(info, PIDS_FETCH_TASKS_ONLY)) == NULL)
xerrx(EXIT_FAILURE,
_("Unable to load process information"));
total_procs = reap->counts->total;
for (i=0; i < total_procs; i++) {
/* is this the login process? */
if (PIDS_GETINT(TGID) == u->ut_pid) {
found_utpid = 1;
if (!best_time) {
best_time = PIDS_GETULL(START);
strncpy(cmdline, PIDS_GETSTR(CMDLINE), MAX_CMD_WIDTH);
*pcpu = PIDS_GETULL(TICS_ALL);
}
}
if (PIDS_GETINT(TTY) != line)
continue;
(*jcpu) += PIDS_VAL(EU_TICS_ALL, ull_int, reap->stacks[i], info);
if (!(secondbest_time && PIDS_GETULL(START) <= secondbest_time)) {
secondbest_time = PIDS_GETULL(START);
if (cmdline[0] == '-' && cmdline[1] == '\0') {
strncpy(cmdline, PIDS_GETSTR(CMDLINE), MAX_CMD_WIDTH);
*pcpu = PIDS_GETULL(TICS_ALL);
}
}
if (
(!ignoreuser && uid != PIDS_GETUNT(EUID)
&& uid != PIDS_GETUNT(RUID))
|| (PIDS_GETINT(PGRP) != PIDS_GETINT(TPGID))
|| (PIDS_GETULL(START) <= best_time)
)
continue;
best_time = PIDS_GETULL(START);
strncpy(cmdline, PIDS_GETSTR(CMDLINE), MAX_CMD_WIDTH);
*pcpu = PIDS_GETULL(TICS_ALL);
}
procps_pids_unref(&info);
return found_utpid;
#undef PIDS_GETINT
#undef PIDS_GETUNT
#undef PIDS_GETULL
#undef PIDS_GETSTR
}
static void showinfo(
utmp_t * u, int formtype, int maxcmd, int from,
const int userlen, const int fromlen, const int ip_addresses)
{
unsigned long long jcpu, pcpu;
unsigned i;
char uname[UT_NAMESIZE + 1] = "", tty[5 + UT_LINESIZE + 1] = "/dev/";
long hertz;
char cmdline[MAX_CMD_WIDTH + 1];
strcpy(cmdline, "-");
hertz = procps_hertz_get();
for (i = 0; i < UT_LINESIZE; i++)
/* clean up tty if garbled */
if (isalnum(u->ut_line[i]) || (u->ut_line[i] == '/'))
tty[i + 5] = u->ut_line[i];
else
tty[i + 5] = '\0';
if (find_best_proc(u, tty + 5, &jcpu, &pcpu, cmdline) == 0)
/*
* just skip if stale utmp entry (i.e. login proc doesn't
* exist). If there is a desire a cmdline flag could be
* added to optionally show it with a prefix of (stale)
* in front of cmd or something like that.
*/
return;
/* force NUL term for printf */
strncpy(uname, u->ut_user, UT_NAMESIZE);
if (formtype) {
printf("%-*.*s%-9.8s", userlen + 1, userlen, uname, u->ut_line);
if (from)
print_from(u, ip_addresses, fromlen);
print_logintime(u->ut_time, stdout);
if (*u->ut_line == ':')
/* idle unknown for xdm logins */
printf(" ?xdm? ");
else
print_time_ival7(idletime(tty), 0, stdout);
print_time_ival7(jcpu / hertz, (jcpu % hertz) * (100. / hertz),
stdout);
if (pcpu > 0)
print_time_ival7(pcpu / hertz,
(pcpu % hertz) * (100. / hertz),
stdout);
else
printf(" ? ");
} else {
printf("%-*.*s%-9.8s", userlen + 1, userlen, u->ut_user,
u->ut_line);
if (from)
print_from(u, ip_addresses, fromlen);
if (*u->ut_line == ':')
/* idle unknown for xdm logins */
printf(" ?xdm? ");
else
print_time_ival7(idletime(tty), 0, stdout);
}
printf(" %.*s\n", maxcmd, cmdline);
}
static void __attribute__ ((__noreturn__))
usage(FILE * out)
{
fputs(USAGE_HEADER, out);
fprintf(out,
_(" %s [options] [user]\n"), program_invocation_short_name);
fputs(USAGE_OPTIONS, out);
fputs(_(" -h, --no-header do not print header\n"),out);
fputs(_(" -u, --no-current ignore current process username\n"),out);
fputs(_(" -s, --short short format\n"),out);
fputs(_(" -f, --from show remote hostname field\n"),out);
fputs(_(" -o, --old-style old style output\n"),out);
fputs(_(" -i, --ip-addr display IP address instead of hostname (if possible)\n"), out);
fputs(USAGE_SEPARATOR, out);
fputs(_(" --help display this help and exit\n"), out);
fputs(USAGE_VERSION, out);
fprintf(out, USAGE_MAN_TAIL("w(1)"));
exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}
int main(int argc, char **argv)
{
char *user = NULL, *p;
utmp_t *u;
struct winsize win;
int ch;
int maxcmd = 80;
int userlen = 8;
int fromlen = 16;
char *env_var;
/* switches (defaults) */
int header = 1;
int longform = 1;
int from = 1;
int ip_addresses = 0;
enum {
HELP_OPTION = CHAR_MAX + 1
};
static const struct option longopts[] = {
{"no-header", no_argument, NULL, 'h'},
{"no-current", no_argument, NULL, 'u'},
{"short", no_argument, NULL, 's'},
{"from", no_argument, NULL, 'f'},
{"old-style", no_argument, NULL, 'o'},
{"ip-addr", no_argument, NULL, 'i'},
{"help", no_argument, NULL, HELP_OPTION},
{"version", no_argument, NULL, 'V'},
{NULL, 0, NULL, 0}
};
#ifdef HAVE_PROGRAM_INVOCATION_NAME
program_invocation_name = program_invocation_short_name;
#endif
setlocale (LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
atexit(close_stdout);
#ifndef W_SHOWFROM
from = 0;
#endif
while ((ch =
getopt_long(argc, argv, "husfoVi", longopts, NULL)) != -1)
switch (ch) {
case 'h':
header = 0;
break;
case 'l':
longform = 1;
break;
case 's':
longform = 0;
break;
case 'f':
from = !from;
break;
case 'V':
printf(PROCPS_NG_VERSION);
exit(0);
case 'u':
ignoreuser = 1;
break;
case 'o':
oldstyle = 1;
break;
case 'i':
ip_addresses = 1;
from = 1;
break;
case HELP_OPTION:
usage(stdout);
default:
usage(stderr);
}
if ((argv[optind]))
user = (argv[optind]);
/* Get user field length from environment */
if ((env_var = getenv("PROCPS_USERLEN")) != NULL) {
int ut_namesize = UT_NAMESIZE;
userlen = atoi(env_var);
if (userlen < 8 || ut_namesize < userlen) {
xwarnx
(_("User length environment PROCPS_USERLEN must be between 8 and %i, ignoring.\n"),
ut_namesize);
userlen = 8;
}
}
/* Get from field length from environment */
if ((env_var = getenv("PROCPS_FROMLEN")) != NULL) {
fromlen = atoi(env_var);
if (fromlen < 8 || UT_HOSTSIZE < fromlen) {
xwarnx
(_("from length environment PROCPS_FROMLEN must be between 8 and %d, ignoring\n"),
UT_HOSTSIZE);
fromlen = 16;
}
}
if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &win) != -1 && win.ws_col > 0)
maxcmd = win.ws_col;
else if ((p = getenv("COLUMNS")))
maxcmd = atoi(p);
else
maxcmd = MAX_CMD_WIDTH;
#define CLAMP_CMD_WIDTH(cw) do { \
if ((cw) < MIN_CMD_WIDTH) (cw) = MIN_CMD_WIDTH; \
if ((cw) > MAX_CMD_WIDTH) (cw) = MAX_CMD_WIDTH; \
} while (0)
CLAMP_CMD_WIDTH(maxcmd);
maxcmd -= 21 + userlen + (from ? fromlen : 0) + (longform ? 20 : 0);
CLAMP_CMD_WIDTH(maxcmd);
#undef CLAMP_CMD_WIDTH
if (header) {
/* print uptime and headers */
printf("%s\n", procps_uptime_sprint());
/* Translation Hint: Following five uppercase messages are
* headers. Try to keep alignment intact. */
printf(_("%-*s TTY "), userlen, _("USER"));
if (from)
printf("%-*s", fromlen - 1, _("FROM"));
if (longform)
printf(_(" LOGIN@ IDLE JCPU PCPU WHAT\n"));
else
printf(_(" IDLE WHAT\n"));
}
utmpname(UTMP_FILE);
setutent();
if (user) {
for (;;) {
u = getutent();
if (!u)
break;
if (u->ut_type != USER_PROCESS)
continue;
if (!strncmp(u->ut_user, user, UT_NAMESIZE))
showinfo(u, longform, maxcmd, from, userlen,
fromlen, ip_addresses);
}
} else {
for (;;) {
u = getutent();
if (!u)
break;
if (u->ut_type != USER_PROCESS)
continue;
if (*u->ut_user)
showinfo(u, longform, maxcmd, from, userlen,
fromlen, ip_addresses);
}
}
endutent();
return EXIT_SUCCESS;
}
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