Library functions relating to the login class capabilities database,

including manpages.
See also login_cap.h.

1 files changed, 371 insertions, 0 deletions

diff --git a/lib/libutil/login_class.c b/lib/libutil/login_class.c
new file mode 100644
index 0000000..1dc6cc4
--- /dev/null
+++ b/lib/libutil/login_class.c
@@ -0,0 +1,371 @@
+/*-
+ * 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
+ *
+ *	$Id$
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <syslog.h>
+#include <login_cap.h>
+#include <paths.h>
+
+
+#undef	UNKNOWN
+#define	UNKNOWN	"su"
+
+
+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    },
+  { "coredumpsize", login_getcapsize, RLIMIT_CORE     },
+  { "memoryuse",    login_getcapsize, RLIMIT_RSS      },
+  { "memorylocked", login_getcapsize, RLIMIT_MEMLOCK  },
+  { "maxproc",	    login_getcapnum,  RLIMIT_NPROC    },
+  { "openfiles",    login_getcapnum,  RLIMIT_NOFILE   },
+  { NULL,	    0,		      0 	      }
+};
+
+
+
+void
+setclassresources(login_cap_t *lc)
+{
+  struct login_res *lr = resources;
+
+  while (lr->what != NULL) {
+    struct rlimit rlim,
+		  newlim;
+    char	  cur[40],
+		  max[40];
+    rlim_t	  rcur,
+		  rmax;
+
+    sprintf(cur, "%s-cur", lr->what);
+    sprintf(max, "%s-max", lr->what);
+
+    /*
+     * 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.
+     */
+
+    getrlimit(lr->why, &rlim);
+    rcur = rlim.rlim_cur;
+    rmax = rlim.rlim_max;
+
+    rcur = (*lr->who)(lc, lr->what, rcur, rcur);
+    rmax = (*lr->who)(lc, lr->what, rmax, rmax);
+    newlim.rlim_cur = (*lr->who)(lc, cur, rcur, rcur);
+    newlim.rlim_max = (*lr->who)(lc, max, rmax, rmax);
+    
+    if (setrlimit(lr->why, &newlim) == -1)
+      syslog(LOG_WARNING, "set class '%s' resource limit %s: %m", lc->lc_class, lr->what);
+
+    ++lr;
+  }
+}
+
+static struct login_vars {
+  const char * tag;
+  const char * var;
+  const char * def;
+} pathvars[] = {
+  { "path",	"PATH",	      NULL    },
+  { "manpath",	"MANPATH",    NULL    },
+  { NULL,	NULL,	      NULL    }
+}, envars[] = {
+  { "lang",	"LANG",	      NULL    },
+  { "charset",	"MM_CHARSET", NULL    },
+  { "timezone", "TZ",	      NULL    },
+  { "term",	"TERM",       UNKNOWN },
+  { NULL,	NULL,	      NULL    }
+};
+
+static char *
+substvar(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;
+
+    if (pwd != NULL) {
+      /*
+       * Count the number of ~'s in var to substitute
+       */
+      p = var;
+      while ((p = strchr(p, '~')) != NULL) {
+	++tildes;
+	++p;
+      }
+
+      /*
+       * Count the number of $'s in var to substitute
+       */
+      p = var;
+      while ((p = strchr(p, '$')) != NULL) {
+        ++dollas;
+        ++p;
+      }
+    }
+
+    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, "~$")) != '\0') {
+	  int l = strlen(p);
+
+	  if (p > var && *(p-1) == '\\')  /* Escaped: */
+	    memmove(p - 1, p, l + 1);	    /* Slide-out the backslash */
+	  else if (*p == '~') {
+	    memmove(p + 1, p + hlen + pch, l);  /* Subst homedir */
+	    memmove(p, pwd->pw_dir, hlen);
+	    if (pch)
+      	      p[hlen] = '/';
+	    p += hlen + pch;
+	  }
+	  else /* if (*p == '$') */ {
+	    memmove(p + 1, p + nlen, 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) {
+    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, 1);
+      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) {
+    char ** set_env = login_getcaplist(lc, "setenv", ",");
+    if (set_env != NULL) {
+      while (*set_env != NULL) {
+	char *p = strchr(*set_env, '=');
+	if (p != NULL) {
+	  char * np = substvar(set_env[1], pwd, hlen, pch, nlen);
+	  if (np != NULL) {
+	    setenv(set_env[0], np, 1);
+	    free(np);
+	  }
+	}
+	++set_env;
+      }
+    }
+  }
+
+}
+
+
+/*
+ * 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 = login_getclassbyname(classname, NULL);
+  flags &= (LOGIN_SETRESOURCES| LOGIN_SETPRIORITY|LOGIN_SETUMASK);
+  rc = setusercontext(lc, NULL, 0, flags);
+  login_close(lc);
+  return rc;
+}
+
+
+/*
+ * 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)
+{
+  int i;
+  login_cap_t * llc = NULL;
+
+  if (lc == NULL)
+  {
+    if (pwd == NULL || (lc = login_getclass(pwd)) == NULL) {
+      return -1;
+    }
+    llc = lc; /* free this when we're done */
+  }
+
+  if (flags & LOGIN_SETPATH)
+    pathvars[0].def = uid ? _PATH_DEFPATH : _PATH_STDPATH;
+
+  /*
+   * Set the process priority
+   */
+  if (flags & LOGIN_SETPRIORITY) {
+    int pri = (int)login_getcapnum(lc, "priority", LOGIN_DEFPRI, LOGIN_DEFPRI);
+    pri = (pri < PRIO_MIN) ? PRIO_MIN : (pri > PRIO_MAX) ? PRIO_MAX : pri;
+    if (setpriority(PRIO_PROCESS, 0, pri) != 0)
+      syslog(LOG_WARNING, "setpriority '%s': %m", pwd->pw_name);
+  }
+
+  /*
+   * Set resources
+   */
+  if (flags & LOGIN_SETRESOURCES)
+    setclassresources(lc);
+
+  /*
+   * 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;	/* You can't be too paranoid */
+  }
+
+  /*
+   * Setup the user's group permissions
+   */
+  if (flags & LOGIN_SETGROUP) {
+    /* XXX is it really a good idea to let errors here go? */
+    if (setgid(pwd->pw_gid) != 0)
+      syslog(LOG_WARNING, "setgid %ld: %m", (long)pwd->pw_gid);
+    if (initgroups(pwd->pw_name, pwd->pw_gid) == -1)
+      syslog(LOG_WARNING, "initgroups '%s': %m", pwd->pw_name);
+  }
+
+  /*
+   * This needs to be done after all of the above.
+   */
+  if ((flags & LOGIN_SETUSER) && setuid(uid) != 0) {
+    syslog(LOG_ERR, "setuid %ld: %m", uid);
+    login_close(llc);
+    return -1;	/* Paranoia again */
+  }
+
+  /*
+   * FreeBSD extension: here we (might) loop and do this twice.
+   * First, for the class we have been given, and next for
+   * any user overrides in ~/.login.conf the user's home directory.
+   */
+  if (flags & LOGIN_SETUMASK)
+    umask(LOGIN_DEFUMASK);    /* Set default umask up front */
+
+  i = 0;
+  while (i < 2 && lc != NULL) {
+
+    if (flags & LOGIN_SETUMASK) {
+      rlim_t tmp = login_getcapnum(lc, "umask", RLIM_INFINITY, RLIM_INFINITY);
+      if (tmp != RLIM_INFINITY)
+	umask((mode_t)tmp);
+    }
+
+    if (flags & LOGIN_SETPATH)
+      setclassenvironment(lc, pwd, 1);
+
+    if (flags & LOGIN_SETENV)
+      setclassenvironment(lc, pwd, 0);
+
+    if (i++ == 0) /* Play it again, Sam */
+      lc = (pwd == NULL) ? NULL : login_getuserclass(pwd);
+  }
+
+  login_close(lc);  /* User's private 'me' class */
+  login_close(llc); /* Class we opened */
+
+  return 0;
+}
+