diff options
Diffstat (limited to 'lib/libutil/login_class.c')
-rw-r--r-- | lib/libutil/login_class.c | 561 |
1 files changed, 561 insertions, 0 deletions
diff --git a/lib/libutil/login_class.c b/lib/libutil/login_class.c new file mode 100644 index 0000000..68fdf2b --- /dev/null +++ b/lib/libutil/login_class.c @@ -0,0 +1,561 @@ +/*- + * Copyright (c) 1996 by + * Sean Eric Fagan <sef@kithrup.com> + * David Nugent <davidn@blaze.net.au> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, is permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice immediately at the beginning of the file, without modification, + * 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. + * 3. This work was done expressly for inclusion into FreeBSD. Other use + * is permitted provided this notation is included. + * 4. Absolutely no warranty of function or purpose is made by the authors. + * 5. Modifications may be freely made to this file providing the above + * conditions are met. + * + * High-level routines relating to use of the user capabilities database + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/param.h> +#include <sys/cpuset.h> +#include <sys/mac.h> +#include <sys/resource.h> +#include <sys/rtprio.h> +#include <sys/stat.h> +#include <sys/time.h> + +#include <ctype.h> +#include <err.h> +#include <errno.h> +#include <fcntl.h> +#include <login_cap.h> +#include <paths.h> +#include <pwd.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <syslog.h> +#include <unistd.h> + + +static struct login_res { + const char *what; + rlim_t (*who)(login_cap_t *, const char *, rlim_t, rlim_t); + int why; +} resources[] = { + { "cputime", login_getcaptime, RLIMIT_CPU }, + { "filesize", login_getcapsize, RLIMIT_FSIZE }, + { "datasize", login_getcapsize, RLIMIT_DATA }, + { "stacksize", login_getcapsize, RLIMIT_STACK }, + { "memoryuse", login_getcapsize, RLIMIT_RSS }, + { "memorylocked", login_getcapsize, RLIMIT_MEMLOCK }, + { "maxproc", login_getcapnum, RLIMIT_NPROC }, + { "openfiles", login_getcapnum, RLIMIT_NOFILE }, + { "coredumpsize", login_getcapsize, RLIMIT_CORE }, + { "sbsize", login_getcapsize, RLIMIT_SBSIZE }, + { "vmemoryuse", login_getcapsize, RLIMIT_VMEM }, + { "pseudoterminals", login_getcapnum, RLIMIT_NPTS }, + { "swapuse", login_getcapsize, RLIMIT_SWAP }, + { NULL, 0, 0 } +}; + + +void +setclassresources(login_cap_t *lc) +{ + struct login_res *lr; + + if (lc == NULL) + return; + + for (lr = resources; lr->what != NULL; ++lr) { + struct rlimit rlim; + + /* + * The login.conf file can have <limit>, <limit>-max, and + * <limit>-cur entries. + * What we do is get the current current- and maximum- limits. + * Then, we try to get an entry for <limit> from the capability, + * using the current and max limits we just got as the + * default/error values. + * *Then*, we try looking for <limit>-cur and <limit>-max, + * again using the appropriate values as the default/error + * conditions. + */ + + if (getrlimit(lr->why, &rlim) != 0) + syslog(LOG_ERR, "getting %s resource limit: %m", lr->what); + else { + char name_cur[40]; + char name_max[40]; + rlim_t rcur = rlim.rlim_cur; + rlim_t rmax = rlim.rlim_max; + + sprintf(name_cur, "%s-cur", lr->what); + sprintf(name_max, "%s-max", lr->what); + + rcur = (*lr->who)(lc, lr->what, rcur, rcur); + rmax = (*lr->who)(lc, lr->what, rmax, rmax); + rlim.rlim_cur = (*lr->who)(lc, name_cur, rcur, rcur); + rlim.rlim_max = (*lr->who)(lc, name_max, rmax, rmax); + + if (setrlimit(lr->why, &rlim) == -1) + syslog(LOG_WARNING, "set class '%s' resource limit %s: %m", lc->lc_class, lr->what); + } + } +} + + + +static struct login_vars { + const char *tag; + const char *var; + const char *def; + int overwrite; +} pathvars[] = { + { "path", "PATH", NULL, 1}, + { "cdpath", "CDPATH", NULL, 1}, + { "manpath", "MANPATH", NULL, 1}, + { NULL, NULL, NULL, 0} +}, envars[] = { + { "lang", "LANG", NULL, 1}, + { "charset", "MM_CHARSET", NULL, 1}, + { "timezone", "TZ", NULL, 1}, + { "term", "TERM", NULL, 0}, + { NULL, NULL, NULL, 0} +}; + +static char * +substvar(const char * var, const struct passwd * pwd, int hlen, int pch, int nlen) +{ + char *np = NULL; + + if (var != NULL) { + int tildes = 0; + int dollas = 0; + char *p; + const char *q; + + if (pwd != NULL) { + for (q = var; *q != '\0'; ++q) { + tildes += (*q == '~'); + dollas += (*q == '$'); + } + } + + np = malloc(strlen(var) + (dollas * nlen) + - dollas + (tildes * (pch+hlen)) + - tildes + 1); + + if (np != NULL) { + p = strcpy(np, var); + + if (pwd != NULL) { + /* + * This loop does user username and homedir substitutions + * for unescaped $ (username) and ~ (homedir) + */ + while (*(p += strcspn(p, "~$")) != '\0') { + int l = strlen(p); + + if (p > np && *(p-1) == '\\') /* Escaped: */ + memmove(p - 1, p, l + 1); /* Slide-out the backslash */ + else if (*p == '~') { + int v = pch && *(p+1) != '/'; /* Avoid double // */ + memmove(p + hlen + v, p + 1, l); /* Subst homedir */ + memmove(p, pwd->pw_dir, hlen); + if (v) + p[hlen] = '/'; + p += hlen + v; + } + else /* if (*p == '$') */ { + memmove(p + nlen, p + 1, l); /* Subst username */ + memmove(p, pwd->pw_name, nlen); + p += nlen; + } + } + } + } + } + + return (np); +} + + +void +setclassenvironment(login_cap_t *lc, const struct passwd * pwd, int paths) +{ + struct login_vars *vars = paths ? pathvars : envars; + int hlen = pwd ? strlen(pwd->pw_dir) : 0; + int nlen = pwd ? strlen(pwd->pw_name) : 0; + char pch = 0; + + if (hlen && pwd->pw_dir[hlen-1] != '/') + ++pch; + + while (vars->tag != NULL) { + const char * var = paths ? login_getpath(lc, vars->tag, NULL) + : login_getcapstr(lc, vars->tag, NULL, NULL); + + char * np = substvar(var, pwd, hlen, pch, nlen); + + if (np != NULL) { + setenv(vars->var, np, vars->overwrite); + free(np); + } else if (vars->def != NULL) { + setenv(vars->var, vars->def, 0); + } + ++vars; + } + + /* + * If we're not processing paths, then see if there is a setenv list by + * which the admin and/or user may set an arbitrary set of env vars. + */ + if (!paths) { + const char **set_env = login_getcaplist(lc, "setenv", ","); + + if (set_env != NULL) { + while (*set_env != NULL) { + char *p = strchr(*set_env, '='); + + if (p != NULL) { /* Discard invalid entries */ + char *np; + + *p++ = '\0'; + if ((np = substvar(p, pwd, hlen, pch, nlen)) != NULL) { + setenv(*set_env, np, 1); + free(np); + } + } + ++set_env; + } + } + } +} + + +static int +list2cpuset(const char *list, cpuset_t *mask) +{ + enum { NONE, NUM, DASH } state; + int lastnum; + int curnum; + const char *l; + + state = NONE; + curnum = lastnum = 0; + for (l = list; *l != '\0';) { + if (isdigit(*l)) { + curnum = atoi(l); + if (curnum > CPU_SETSIZE) + errx(EXIT_FAILURE, + "Only %d cpus supported", CPU_SETSIZE); + while (isdigit(*l)) + l++; + switch (state) { + case NONE: + lastnum = curnum; + state = NUM; + break; + case DASH: + for (; lastnum <= curnum; lastnum++) + CPU_SET(lastnum, mask); + state = NONE; + break; + case NUM: + default: + return (0); + } + continue; + } + switch (*l) { + case ',': + switch (state) { + case NONE: + break; + case NUM: + CPU_SET(curnum, mask); + state = NONE; + break; + case DASH: + return (0); + break; + } + break; + case '-': + if (state != NUM) + return (0); + state = DASH; + break; + default: + return (0); + } + l++; + } + switch (state) { + case NONE: + break; + case NUM: + CPU_SET(curnum, mask); + break; + case DASH: + return (0); + } + return (1); +} + + +void +setclasscpumask(login_cap_t *lc) +{ + const char *maskstr; + cpuset_t maskset; + cpusetid_t setid; + + maskstr = login_getcapstr(lc, "cpumask", NULL, NULL); + CPU_ZERO(&maskset); + if (maskstr == NULL) + return; + if (strcasecmp("default", maskstr) == 0) + return; + if (!list2cpuset(maskstr, &maskset)) { + syslog(LOG_WARNING, + "list2cpuset(%s) invalid mask specification", maskstr); + return; + } + + if (cpuset(&setid) != 0) { + syslog(LOG_ERR, "cpuset(): %s", strerror(errno)); + return; + } + + if (cpuset_setaffinity(CPU_LEVEL_CPUSET, CPU_WHICH_PID, -1, + sizeof(maskset), &maskset) != 0) + syslog(LOG_ERR, "cpuset_setaffinity(%s): %s", maskstr, + strerror(errno)); +} + + +/* + * setclasscontext() + * + * For the login class <class>, set various class context values + * (limits, mainly) to the values for that class. Which values are + * set are controlled by <flags> -- see <login_class.h> for the + * possible values. + * + * setclasscontext() can only set resources, priority, and umask. + */ + +int +setclasscontext(const char *classname, unsigned int flags) +{ + int rc; + login_cap_t *lc; + + lc = login_getclassbyname(classname, NULL); + + flags &= LOGIN_SETRESOURCES | LOGIN_SETPRIORITY | + LOGIN_SETUMASK | LOGIN_SETPATH; + + rc = lc ? setusercontext(lc, NULL, 0, flags) : -1; + login_close(lc); + return (rc); +} + + + +/* + * Private function which takes care of processing + */ + +static mode_t +setlogincontext(login_cap_t *lc, const struct passwd *pwd, + mode_t mymask, unsigned long flags) +{ + if (lc) { + /* Set resources */ + if (flags & LOGIN_SETRESOURCES) + setclassresources(lc); + /* See if there's a umask override */ + if (flags & LOGIN_SETUMASK) + mymask = (mode_t)login_getcapnum(lc, "umask", mymask, mymask); + /* Set paths */ + if (flags & LOGIN_SETPATH) + setclassenvironment(lc, pwd, 1); + /* Set environment */ + if (flags & LOGIN_SETENV) + setclassenvironment(lc, pwd, 0); + /* Set cpu affinity */ + if (flags & LOGIN_SETCPUMASK) + setclasscpumask(lc); + } + return (mymask); +} + + + +/* + * setusercontext() + * + * Given a login class <lc> and a user in <pwd>, with a uid <uid>, + * set the context as in setclasscontext(). <flags> controls which + * values are set. + * + * The difference between setclasscontext() and setusercontext() is + * that the former sets things up for an already-existing process, + * while the latter sets things up from a root context. Such as might + * be called from login(1). + * + */ + +int +setusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned int flags) +{ + quad_t p; + mode_t mymask; + login_cap_t *llc = NULL; + struct sigaction sa, prevsa; + struct rtprio rtp; + int error; + + if (lc == NULL) { + if (pwd != NULL && (lc = login_getpwclass(pwd)) != NULL) + llc = lc; /* free this when we're done */ + } + + if (flags & LOGIN_SETPATH) + pathvars[0].def = uid ? _PATH_DEFPATH : _PATH_STDPATH; + + /* we need a passwd entry to set these */ + if (pwd == NULL) + flags &= ~(LOGIN_SETGROUP | LOGIN_SETLOGIN | LOGIN_SETMAC); + + /* Set the process priority */ + if (flags & LOGIN_SETPRIORITY) { + p = login_getcapnum(lc, "priority", LOGIN_DEFPRI, LOGIN_DEFPRI); + + if (p > PRIO_MAX) { + rtp.type = RTP_PRIO_IDLE; + rtp.prio = p - PRIO_MAX - 1; + p = (rtp.prio > RTP_PRIO_MAX) ? 31 : p; + if (rtprio(RTP_SET, 0, &rtp)) + syslog(LOG_WARNING, "rtprio '%s' (%s): %m", + pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); + } else if (p < PRIO_MIN) { + rtp.type = RTP_PRIO_REALTIME; + rtp.prio = abs(p - PRIO_MIN + RTP_PRIO_MAX); + p = (rtp.prio > RTP_PRIO_MAX) ? 1 : p; + if (rtprio(RTP_SET, 0, &rtp)) + syslog(LOG_WARNING, "rtprio '%s' (%s): %m", + pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); + } else { + if (setpriority(PRIO_PROCESS, 0, (int)p) != 0) + syslog(LOG_WARNING, "setpriority '%s' (%s): %m", + pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); + } + } + + /* Setup the user's group permissions */ + if (flags & LOGIN_SETGROUP) { + if (setgid(pwd->pw_gid) != 0) { + syslog(LOG_ERR, "setgid(%lu): %m", (u_long)pwd->pw_gid); + login_close(llc); + return (-1); + } + if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) { + syslog(LOG_ERR, "initgroups(%s,%lu): %m", pwd->pw_name, + (u_long)pwd->pw_gid); + login_close(llc); + return (-1); + } + } + + /* Set up the user's MAC label. */ + if ((flags & LOGIN_SETMAC) && mac_is_present(NULL) == 1) { + const char *label_string; + mac_t label; + + label_string = login_getcapstr(lc, "label", NULL, NULL); + if (label_string != NULL) { + if (mac_from_text(&label, label_string) == -1) { + syslog(LOG_ERR, "mac_from_text('%s') for %s: %m", + pwd->pw_name, label_string); + return (-1); + } + if (mac_set_proc(label) == -1) + error = errno; + else + error = 0; + mac_free(label); + if (error != 0) { + syslog(LOG_ERR, "mac_set_proc('%s') for %s: %s", + label_string, pwd->pw_name, strerror(error)); + return (-1); + } + } + } + + /* Set the sessions login */ + if ((flags & LOGIN_SETLOGIN) && setlogin(pwd->pw_name) != 0) { + syslog(LOG_ERR, "setlogin(%s): %m", pwd->pw_name); + login_close(llc); + return (-1); + } + + /* Inform the kernel about current login class */ + if (lc != NULL && lc->lc_class != NULL && (flags & LOGIN_SETLOGINCLASS)) { + /* + * XXX: This is a workaround to fail gracefully in case the kernel + * does not support setloginclass(2). + */ + bzero(&sa, sizeof(sa)); + sa.sa_handler = SIG_IGN; + sigfillset(&sa.sa_mask); + sigaction(SIGSYS, &sa, &prevsa); + error = setloginclass(lc->lc_class); + sigaction(SIGSYS, &prevsa, NULL); + if (error != 0) { + syslog(LOG_ERR, "setloginclass(%s): %m", lc->lc_class); +#ifdef notyet + login_close(llc); + return (-1); +#endif + } + } + + mymask = (flags & LOGIN_SETUMASK) ? umask(LOGIN_DEFUMASK) : 0; + mymask = setlogincontext(lc, pwd, mymask, flags); + login_close(llc); + + /* This needs to be done after anything that needs root privs */ + if ((flags & LOGIN_SETUSER) && setuid(uid) != 0) { + syslog(LOG_ERR, "setuid(%lu): %m", (u_long)uid); + return (-1); /* Paranoia again */ + } + + /* + * Now, we repeat some of the above for the user's private entries + */ + if (getuid() == uid && (lc = login_getuserclass(pwd)) != NULL) { + mymask = setlogincontext(lc, pwd, mymask, flags); + login_close(lc); + } + + /* Finally, set any umask we've found */ + if (flags & LOGIN_SETUMASK) + umask(mymask); + + return (0); +} |