/* pam_access module */ /* * Written by Alexei Nogin 1997/06/15 * (I took login_access from logdaemon-5.6 and converted it to PAM * using parts of pam_time code.) * ************************************************************************ * Copyright message from logdaemon-5.6 (original file name DISCLAIMER) ************************************************************************ * Copyright 1995 by Wietse Venema. All rights reserved. Individual files * may be covered by other copyrights (as noted in the file itself.) * * This material was originally written and compiled by Wietse Venema at * Eindhoven University of Technology, The Netherlands, in 1990, 1991, * 1992, 1993, 1994 and 1995. * * Redistribution and use in source and binary forms are permitted * provided that this entire copyright notice is duplicated in all such * copies. * * This software is provided "as is" and without any expressed or implied * warranties, including, without limitation, the implied warranties of * merchantibility and fitness for any particular purpose. ************************************************************************* */ #include "config.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * here, we make definitions for the externally accessible functions * in this file (these definitions are required for static modules * but strongly encouraged generally) they are used to instruct the * modules include file to define their prototypes. */ #define PAM_SM_AUTH #define PAM_SM_ACCOUNT #define PAM_SM_SESSION #define PAM_SM_PASSWORD #include #include #include #include /* login_access.c from logdaemon-5.6 with several changes by A.Nogin: */ /* * This module implements a simple but effective form of login access * control based on login names and on host (or domain) names, internet * addresses (or network numbers), or on terminal line names in case of * non-networked logins. Diagnostics are reported through syslog(3). * * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands. */ #if !defined(MAXHOSTNAMELEN) || (MAXHOSTNAMELEN < 64) #undef MAXHOSTNAMELEN #define MAXHOSTNAMELEN 256 #endif /* Delimiters for fields and for lists of users, ttys or hosts. */ static const char *fs = ":"; /* field separator */ static const char *sep = ", \t"; /* list-element separator */ /* Constants to be used in assignments only, not in comparisons... */ #define YES 1 #define NO 0 /* * A structure to bundle up all login-related information to keep the * functional interfaces as generic as possible. */ struct login_info { const struct passwd *user; const char *from; const char *config_file; }; /* Print debugging messages. Default is NO which means don't print debugging messages. */ static char pam_access_debug = NO; /* Parse module config arguments */ static int parse_args(pam_handle_t *pamh, struct login_info *loginfo, int argc, const char **argv) { int i; for (i=0; iconfig_file = 11 + argv[i]; fclose(fp); } else { pam_syslog(pamh, LOG_ERR, "failed to open accessfile=[%s]: %m", 11 + argv[i]); return 0; } } else if (strcmp (argv[i], "debug") == 0) { pam_access_debug = YES; } else { pam_syslog(pamh, LOG_ERR, "unrecognized option [%s]", argv[i]); } } return 1; /* OK */ } /* --- static functions for checking whether the user should be let in --- */ typedef int match_func (pam_handle_t *, char *, struct login_info *); static int list_match (pam_handle_t *, char *, struct login_info *, match_func *); static int user_match (pam_handle_t *, char *, struct login_info *); static int from_match (pam_handle_t *, char *, struct login_info *); static int string_match (pam_handle_t *, const char *, const char *); static int network_netmask_match (pam_handle_t *, const char *, const char *); /* isipaddr - find out if string provided is an IP address or not */ static int isipaddr (const char *string, int *addr_type, struct sockaddr_storage *addr) { struct sockaddr_storage local_addr; int is_ip; /* We use struct sockaddr_storage addr because * struct in_addr/in6_addr is an integral part * of struct sockaddr and we doesn't want to * use its value. */ if (addr == NULL) addr = &local_addr; memset(addr, 0, sizeof(struct sockaddr_storage)); /* first ipv4 */ if (inet_pton(AF_INET, string, addr) > 0) { if (addr_type != NULL) *addr_type = AF_INET; is_ip = YES; } else if (inet_pton(AF_INET6, string, addr) > 0) { /* then ipv6 */ if (addr_type != NULL) { *addr_type = AF_INET6; } is_ip = YES; } else is_ip = NO; return is_ip; } /* are_addresses_equal - translate IP address strings to real IP * addresses and compare them to find out if they are equal. * If netmask was provided it will be used to focus comparation to * relevant bits. */ static int are_addresses_equal (const char *ipaddr0, const char *ipaddr1, const char *netmask) { struct sockaddr_storage addr0; struct sockaddr_storage addr1; int addr_type0 = 0; int addr_type1 = 0; if (isipaddr (ipaddr0, &addr_type0, &addr0) == NO) return NO; if (isipaddr (ipaddr1, &addr_type1, &addr1) == NO) return NO; if (addr_type0 != addr_type1) /* different address types */ return NO; if (netmask != NULL) { /* Got a netmask, so normalize addresses? */ struct sockaddr_storage nmask; unsigned char *byte_a, *byte_nm; memset(&nmask, 0, sizeof(struct sockaddr_storage)); if (inet_pton(addr_type0, netmask, (void *)&nmask) > 0) { unsigned int i; byte_a = (unsigned char *)(&addr0); byte_nm = (unsigned char *)(&nmask); for (i=0; i= 8) { byte_nm[i] = 0xff; netmask -= 8; } else if (netmask > 0) { byte_nm[i] = 0xff << (8 - netmask); break; } else if (netmask <= 0) { break; } } /* now generate netmask address string */ ipaddr_dst = inet_ntop(addr_type, &nmask, ipaddr_buf, ipaddr_buf_len); if (ipaddr_dst == ipaddr_buf) { return (ipaddr_buf); } return (NULL); } /* login_access - match username/group and host/tty with access control file */ static int login_access (pam_handle_t *pamh, struct login_info *item) { FILE *fp; char line[BUFSIZ]; char *perm; /* becomes permission field */ char *users; /* becomes list of login names */ char *froms; /* becomes list of terminals or hosts */ int match = NO; int end; int lineno = 0; /* for diagnostics */ char *sptr; if (pam_access_debug) pam_syslog (pamh, LOG_DEBUG, "login_access: user=%s, from=%s, file=%s", item->user->pw_name, item->from, item->config_file); /* * Process the table one line at a time and stop at the first match. * Blank lines and lines that begin with a '#' character are ignored. * Non-comment lines are broken at the ':' character. All fields are * mandatory. The first field should be a "+" or "-" character. A * non-existing table means no access control. */ if ((fp = fopen(item->config_file, "r"))!=NULL) { while (!match && fgets(line, sizeof(line), fp)) { lineno++; if (line[end = strlen(line) - 1] != '\n') { pam_syslog(pamh, LOG_ERR, "%s: line %d: missing newline or line too long", item->config_file, lineno); continue; } if (line[0] == '#') continue; /* comment line */ while (end > 0 && isspace(line[end - 1])) end--; line[end] = 0; /* strip trailing whitespace */ if (line[0] == 0) /* skip blank lines */ continue; /* Allow field seperator in last field of froms */ if (!(perm = strtok_r(line, fs, &sptr)) || !(users = strtok_r(NULL, fs, &sptr)) || !(froms = strtok_r(NULL, "\n", &sptr))) { pam_syslog(pamh, LOG_ERR, "%s: line %d: bad field count", item->config_file, lineno); continue; } if (perm[0] != '+' && perm[0] != '-') { pam_syslog(pamh, LOG_ERR, "%s: line %d: bad first field", item->config_file, lineno); continue; } if (pam_access_debug) pam_syslog (pamh, LOG_DEBUG, "line %d: %s : %s : %s", lineno, perm, users, froms); match = list_match(pamh, froms, item, from_match); if (pam_access_debug) pam_syslog (pamh, LOG_DEBUG, "from_match=%d, \"%s\"", match, item->from); match = match && list_match (pamh, users, item, user_match); if (pam_access_debug) pam_syslog (pamh, LOG_DEBUG, "user_match=%d, \"%s\"", match, item->user->pw_name); } (void) fclose(fp); } else if (errno == ENOENT) { /* This is no error. */ pam_syslog(pamh, LOG_WARNING, "warning: cannot open %s: %m", item->config_file); } else { pam_syslog(pamh, LOG_ERR, "cannot open %s: %m", item->config_file); return NO; } return (match == NO || (line[0] == '+')); } /* list_match - match an item against a list of tokens with exceptions */ static int list_match(pam_handle_t *pamh, char *list, struct login_info *item, match_func *match_fn) { char *tok; int match = NO; char *sptr; /* * Process tokens one at a time. We have exhausted all possible matches * when we reach an "EXCEPT" token or the end of the list. If we do find * a match, look for an "EXCEPT" list and recurse to determine whether * the match is affected by any exceptions. */ for (tok = strtok_r(list, sep, &sptr); tok != 0; tok = strtok_r(NULL, sep, &sptr)) { if (strcasecmp(tok, "EXCEPT") == 0) /* EXCEPT: give up */ break; if ((match = (*match_fn) (pamh, tok, item))) /* YES */ break; } /* Process exceptions to matches. */ if (match != NO) { while ((tok = strtok_r(NULL, sep, &sptr)) && strcasecmp(tok, "EXCEPT")) /* VOID */ ; if (tok == 0 || list_match(pamh, (char *) 0, item, match_fn) == NO) return (match); } return (NO); } /* myhostname - figure out local machine name */ static char * myhostname(void) { static char name[MAXHOSTNAMELEN + 1]; if (gethostname(name, MAXHOSTNAMELEN) == 0) { name[MAXHOSTNAMELEN] = 0; return (name); } return NULL; } /* netgroup_match - match group against machine or user */ static int netgroup_match (pam_handle_t *pamh, const char *group, const char *machine, const char *user) { char *mydomain = NULL; int retval; yp_get_default_domain(&mydomain); retval = innetgr (group, machine, user, mydomain); if (pam_access_debug == YES) pam_syslog (pamh, LOG_DEBUG, "netgroup_match: %d (group=%s, machine=%s, user=%s, domain=%s)", retval, group ? group : "NULL", machine ? machine : "NULL", user ? user : "NULL", mydomain ? mydomain : "NULL"); return retval; } /* user_match - match a username against one token */ static int user_match (pam_handle_t *pamh, char *tok, struct login_info *item) { char *string = item->user->pw_name; struct login_info fake_item; char *at; if (pam_access_debug) pam_syslog (pamh, LOG_DEBUG, "user_match: tok=%s, item=%s", tok, string); /* * If a token has the magic value "ALL" the match always succeeds. * Otherwise, return YES if the token fully matches the username, if the * token is a group that contains the username, or if the token is the * name of the user's primary group. */ if ((at = strchr(tok + 1, '@')) != 0) { /* split user@host pattern */ *at = 0; fake_item.from = myhostname(); if (fake_item.from == NULL) return NO; return (user_match (pamh, tok, item) && from_match (pamh, at + 1, &fake_item)); } else if (tok[0] == '@') /* netgroup */ return (netgroup_match (pamh, tok + 1, (char *) 0, string)); else if (string_match (pamh, tok, string)) /* ALL or exact match */ return YES; else if (pam_modutil_user_in_group_nam_nam (pamh, item->user->pw_name, tok)) /* try group membership */ return YES; return NO; } /* from_match - match a host or tty against a list of tokens */ static int from_match (pam_handle_t *pamh UNUSED, char *tok, struct login_info *item) { const char *string = item->from; int tok_len; int str_len; if (pam_access_debug) pam_syslog (pamh, LOG_DEBUG, "from_match: tok=%s, item=%s", tok, string); /* * If a token has the magic value "ALL" the match always succeeds. Return * YES if the token fully matches the string. If the token is a domain * name, return YES if it matches the last fields of the string. If the * token has the magic value "LOCAL", return YES if the string does not * contain a "." character. If the token is a network number, return YES * if it matches the head of the string. */ if (string == NULL) { return NO; } else if (tok[0] == '@') { /* netgroup */ return (netgroup_match (pamh, tok + 1, string, (char *) 0)); } else if (string_match(pamh, tok, string)) { /* ALL or exact match */ return (YES); } else if (tok[0] == '.') { /* domain: match last fields */ if ((str_len = strlen(string)) > (tok_len = strlen(tok)) && strcasecmp(tok, string + str_len - tok_len) == 0) return (YES); } else if (strcasecmp(tok, "LOCAL") == 0) { /* local: no dots */ if (strchr(string, '.') == 0) return (YES); } else if (tok[(tok_len = strlen(tok)) - 1] == '.') { struct addrinfo *res; struct addrinfo hint; memset (&hint, '\0', sizeof (hint)); hint.ai_flags = AI_CANONNAME; hint.ai_family = AF_INET; if (getaddrinfo (string, NULL, &hint, &res) != 0) return NO; else { struct addrinfo *runp = res; while (runp != NULL) { char buf[INET_ADDRSTRLEN+2]; if (runp->ai_family == AF_INET) { inet_ntop (runp->ai_family, &((struct sockaddr_in *) runp->ai_addr)->sin_addr, buf, sizeof (buf)); strcat (buf, "."); if (strncmp(tok, buf, tok_len) == 0) { freeaddrinfo (res); return YES; } } runp = runp->ai_next; } freeaddrinfo (res); } } else if (isipaddr(string, NULL, NULL) == YES) { /* Assume network/netmask with a IP of a host. */ if (network_netmask_match(pamh, tok, string)) return YES; } else { /* Assume network/netmask with a name of a host. */ struct addrinfo *res; struct addrinfo hint; memset (&hint, '\0', sizeof (hint)); hint.ai_flags = AI_CANONNAME; hint.ai_family = AF_UNSPEC; if (getaddrinfo (string, NULL, &hint, &res) != 0) return NO; else { struct addrinfo *runp = res; while (runp != NULL) { char buf[INET6_ADDRSTRLEN]; inet_ntop (runp->ai_family, runp->ai_family == AF_INET ? (void *) &((struct sockaddr_in *) runp->ai_addr)->sin_addr : (void *) &((struct sockaddr_in6 *) runp->ai_addr)->sin6_addr, buf, sizeof (buf)); if (network_netmask_match(pamh, tok, buf)) { freeaddrinfo (res); return YES; } runp = runp->ai_next; } freeaddrinfo (res); } } return NO; } /* string_match - match a string against one token */ static int string_match (pam_handle_t *pamh, const char *tok, const char *string) { if (pam_access_debug) pam_syslog (pamh, LOG_DEBUG, "string_match: tok=%s, item=%s", tok, string); /* * If the token has the magic value "ALL" the match always succeeds. * Otherwise, return YES if the token fully matches the string. * "NONE" token matches NULL string. */ if (strcasecmp(tok, "ALL") == 0) { /* all: always matches */ return (YES); } else if (string != NULL) { if (strcasecmp(tok, string) == 0) { /* try exact match */ return (YES); } } else if (strcasecmp(tok, "NONE") == 0) { return (YES); } return (NO); } /* network_netmask_match - match a string against one token * where string is an ip (v4,v6) address and tok represents * whether a single ip (v4,v6) address or a network/netmask */ static int network_netmask_match (pam_handle_t *pamh, const char *tok, const char *string) { if (pam_access_debug) pam_syslog (pamh, LOG_DEBUG, "network_netmask_match: tok=%s, item=%s", tok, string); if (isipaddr(string, NULL, NULL) == YES) { char *netmask_ptr = NULL; static char netmask_string[MAXHOSTNAMELEN + 1] = ""; int addr_type; /* OK, check if tok is of type addr/mask */ if ((netmask_ptr = strchr(tok, '/')) != NULL) { long netmask = 0; /* YES */ *netmask_ptr = 0; netmask_ptr++; if (isipaddr(tok, &addr_type, NULL) == NO) { /* no netaddr */ return(NO); } /* check netmask */ if (isipaddr(netmask_ptr, NULL, NULL) == NO) { /* netmask as integre value */ char *endptr = NULL; netmask = strtol(netmask_ptr, &endptr, 0); if ((endptr == NULL) || (*endptr != '\0')) { /* invalid netmask value */ return(NO); } if ((netmask < 0) || (netmask >= 128)) { /* netmask value out of range */ return(NO); } netmask_ptr = number_to_netmask(netmask, addr_type, netmask_string, MAXHOSTNAMELEN); } /* Netmask is now an ipv4/ipv6 address. * This works also if netmask_ptr is NULL. */ return (are_addresses_equal(string, tok, netmask_ptr)); } else /* NO, then check if it is only an addr */ if (isipaddr(tok, NULL, NULL) == YES) { /* check if they are the same, no netmask */ return(are_addresses_equal(string, tok, NULL)); } } return (NO); } /* --- public PAM management functions --- */ PAM_EXTERN int pam_sm_authenticate (pam_handle_t *pamh, int flags UNUSED, int argc, const char **argv) { struct login_info loginfo; const char *user=NULL; const void *void_from=NULL; const char *from; struct passwd *user_pw; /* set username */ if (pam_get_user(pamh, &user, NULL) != PAM_SUCCESS || user == NULL || *user == '\0') { pam_syslog(pamh, LOG_ERR, "cannot determine the user's name"); return PAM_USER_UNKNOWN; } /* remote host name */ if (pam_get_item(pamh, PAM_RHOST, &void_from) != PAM_SUCCESS) { pam_syslog(pamh, LOG_ERR, "cannot find the remote host name"); return PAM_ABORT; } from = void_from; if ((from==NULL) || (*from=='\0')) { /* local login, set tty name */ if (pam_get_item(pamh, PAM_TTY, &void_from) != PAM_SUCCESS || void_from == NULL) { D(("PAM_TTY not set, probing stdin")); from = ttyname(STDIN_FILENO); if (from != NULL) { if (pam_set_item(pamh, PAM_TTY, from) != PAM_SUCCESS) pam_syslog(pamh, LOG_WARNING, "couldn't set tty name"); } else { if (pam_get_item(pamh, PAM_SERVICE, &void_from) != PAM_SUCCESS || void_from == NULL) { pam_syslog (pamh, LOG_ERR, "cannot determine remote host, tty or service name"); return PAM_ABORT; } from = void_from; if (pam_access_debug) pam_syslog (pamh, LOG_DEBUG, "cannot determine tty or remote hostname, using service %s", from); } } else from = void_from; if (from[0] == '/') { /* full path, remove device path. */ const char *f; from++; if ((f = strchr(from, '/')) != NULL) { from = f + 1; } } } if ((user_pw=pam_modutil_getpwnam(pamh, user))==NULL) return (PAM_USER_UNKNOWN); /* * Bundle up the arguments to avoid unnecessary clumsiness later on. */ loginfo.user = user_pw; loginfo.from = from; loginfo.config_file = PAM_ACCESS_CONFIG; /* parse the argument list */ if (!parse_args(pamh, &loginfo, argc, argv)) { pam_syslog(pamh, LOG_ERR, "failed to parse the module arguments"); return PAM_ABORT; } if (login_access(pamh, &loginfo)) { return (PAM_SUCCESS); } else { pam_syslog(pamh, LOG_ERR, "access denied for user `%s' from `%s'",user,from); return (PAM_PERM_DENIED); } } PAM_EXTERN int pam_sm_setcred (pam_handle_t *pamh UNUSED, int flags UNUSED, int argc UNUSED, const char **argv UNUSED) { return PAM_IGNORE; } PAM_EXTERN int pam_sm_acct_mgmt (pam_handle_t *pamh, int flags, int argc, const char **argv) { return pam_sm_authenticate (pamh, flags, argc, argv); } PAM_EXTERN int pam_sm_open_session(pam_handle_t *pamh, int flags, int argc, const char **argv) { return pam_sm_authenticate(pamh, flags, argc, argv); } PAM_EXTERN int pam_sm_close_session(pam_handle_t *pamh, int flags, int argc, const char **argv) { return pam_sm_authenticate(pamh, flags, argc, argv); } PAM_EXTERN int pam_sm_chauthtok(pam_handle_t *pamh, int flags, int argc, const char **argv) { return pam_sm_authenticate(pamh, flags, argc, argv); } /* end of module definition */ #ifdef PAM_STATIC /* static module data */ struct pam_module _pam_access_modstruct = { "pam_access", pam_sm_authenticate, pam_sm_setcred, pam_sm_acct_mgmt, pam_sm_open_session, pam_sm_close_session, pam_sm_chauthtok }; #endif