Adding upstream version 1.3.1.upstream/1.3.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1030 insertions, 0 deletions

diff --git a/libpam/pam_handlers.c b/libpam/pam_handlers.c
new file mode 100644
index 0000000..106ef7c
--- /dev/null
+++ b/libpam/pam_handlers.c
@@ -0,0 +1,1030 @@
+/* pam_handlers.c -- pam config file parsing and module loading */
+
+/*
+ * created by Marc Ewing.
+ * Currently maintained by Andrew G. Morgan <morgan@kernel.org>
+ *
+ */
+
+#include "pam_private.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#define BUF_SIZE                  1024
+#define MODULE_CHUNK              4
+#define UNKNOWN_MODULE       "<*unknown module*>"
+#ifndef _PAM_ISA
+#define _PAM_ISA "."
+#endif
+
+static int _pam_assemble_line(FILE *f, char *buf, int buf_len);
+
+static void _pam_free_handlers_aux(struct handler **hp);
+
+static int _pam_add_handler(pam_handle_t *pamh
+		     , int must_fail, int other, int stack_level, int type
+		     , int *actions, const char *mod_path
+		     , int argc, char **argv, int argvlen);
+
+/* Values for module type */
+
+#define PAM_T_ANY     0
+#define PAM_T_AUTH    1
+#define PAM_T_SESS    2
+#define PAM_T_ACCT    4
+#define PAM_T_PASS    8
+
+static int _pam_load_conf_file(pam_handle_t *pamh, const char *config_name
+				, const char *service /* specific file */
+				, int module_type /* specific type */
+				, int stack_level /* level of substack */
+#ifdef PAM_READ_BOTH_CONFS
+				, int not_other
+#endif /* PAM_READ_BOTH_CONFS */
+    );
+
+static int _pam_parse_conf_file(pam_handle_t *pamh, FILE *f
+				, const char *known_service /* specific file */
+				, int requested_module_type /* specific type */
+				, int stack_level /* level of substack */
+#ifdef PAM_READ_BOTH_CONFS
+				, int not_other
+#endif /* PAM_READ_BOTH_CONFS */
+    )
+{
+    char buf[BUF_SIZE];
+    int x;                    /* read a line from the FILE *f ? */
+    /*
+     * read a line from the configuration (FILE *) f
+     */
+    while ((x = _pam_assemble_line(f, buf, BUF_SIZE)) > 0) {
+	char *tok, *nexttok=NULL;
+	const char *this_service;
+	const char *mod_path;
+	int module_type, actions[_PAM_RETURN_VALUES];
+	int other;            /* set if module is for PAM_DEFAULT_SERVICE */
+	int res;              /* module added successfully? */
+	int handler_type = PAM_HT_MODULE; /* regular handler from a module */
+	int argc;
+	char **argv;
+	int argvlen;
+
+	D(("_pam_init_handler: LINE: %s", buf));
+	if (known_service != NULL) {
+	    nexttok = buf;
+	    /* No service field: all lines are for the known service. */
+	    this_service = known_service;
+	} else {
+	    this_service = tok = _pam_StrTok(buf, " \n\t", &nexttok);
+	}
+
+#ifdef PAM_READ_BOTH_CONFS
+	if (not_other)
+	    other = 0;
+	else
+#endif /* PAM_READ_BOTH_CONFS */
+	other = !strcasecmp(this_service, PAM_DEFAULT_SERVICE);
+
+	/* accept "service name" or PAM_DEFAULT_SERVICE modules */
+	if (!strcasecmp(this_service, pamh->service_name) || other) {
+	    int pam_include = 0;
+	    int substack = 0;
+
+	    /* This is a service we are looking for */
+	    D(("_pam_init_handlers: Found PAM config entry for: %s"
+	       , this_service));
+
+	    tok = _pam_StrTok(NULL, " \n\t", &nexttok);
+	    if (tok == NULL) {
+	        /* module type does not exist */
+	        D(("_pam_init_handlers: empty module type for %s", this_service));
+	        pam_syslog(pamh, LOG_ERR,
+			   "(%s) empty module type", this_service);
+	        module_type = (requested_module_type != PAM_T_ANY) ?
+		  requested_module_type : PAM_T_AUTH;	/* most sensitive */
+	        handler_type = PAM_HT_MUST_FAIL; /* install as normal but fail when dispatched */
+	    } else {
+		if (tok[0] == '-') { /* do not log module load errors */
+		    handler_type = PAM_HT_SILENT_MODULE;
+		    ++tok;
+		}
+		if (!strcasecmp("auth", tok)) {
+		    module_type = PAM_T_AUTH;
+		} else if (!strcasecmp("session", tok)) {
+		    module_type = PAM_T_SESS;
+		} else if (!strcasecmp("account", tok)) {
+		    module_type = PAM_T_ACCT;
+		} else if (!strcasecmp("password", tok)) {
+		    module_type = PAM_T_PASS;
+		} else {
+		    /* Illegal module type */
+		    D(("_pam_init_handlers: bad module type: %s", tok));
+		    pam_syslog(pamh, LOG_ERR, "(%s) illegal module type: %s",
+			    this_service, tok);
+		    module_type = (requested_module_type != PAM_T_ANY) ?
+			    requested_module_type : PAM_T_AUTH;	/* most sensitive */
+		    handler_type = PAM_HT_MUST_FAIL; /* install as normal but fail when dispatched */
+		}
+	    }
+	    D(("Using %s config entry: %s", handler_type?"BAD ":"", tok));
+	    if (requested_module_type != PAM_T_ANY &&
+	        module_type != requested_module_type) {
+		D(("Skipping config entry: %s (requested=%d, found=%d)",
+		   tok, requested_module_type, module_type));
+		continue;
+	    }
+
+	    /* reset the actions to .._UNDEF's -- this is so that
+               we can work out which entries are not yet set (for default). */
+	    {
+		int i;
+		for (i=0; i<_PAM_RETURN_VALUES;
+		     actions[i++] = _PAM_ACTION_UNDEF);
+	    }
+	    tok = _pam_StrTok(NULL, " \n\t", &nexttok);
+	    if (tok == NULL) {
+		/* no module name given */
+		D(("_pam_init_handlers: no control flag supplied"));
+		pam_syslog(pamh, LOG_ERR,
+			   "(%s) no control flag supplied", this_service);
+		_pam_set_default_control(actions, _PAM_ACTION_BAD);
+		handler_type = PAM_HT_MUST_FAIL;
+	    } else if (!strcasecmp("required", tok)) {
+		D(("*PAM_F_REQUIRED*"));
+		actions[PAM_SUCCESS] = _PAM_ACTION_OK;
+		actions[PAM_NEW_AUTHTOK_REQD] = _PAM_ACTION_OK;
+                actions[PAM_IGNORE] = _PAM_ACTION_IGNORE;
+		_pam_set_default_control(actions, _PAM_ACTION_BAD);
+	    } else if (!strcasecmp("requisite", tok)) {
+		D(("*PAM_F_REQUISITE*"));
+		actions[PAM_SUCCESS] = _PAM_ACTION_OK;
+		actions[PAM_NEW_AUTHTOK_REQD] = _PAM_ACTION_OK;
+                actions[PAM_IGNORE] = _PAM_ACTION_IGNORE;
+		_pam_set_default_control(actions, _PAM_ACTION_DIE);
+	    } else if (!strcasecmp("optional", tok)) {
+		D(("*PAM_F_OPTIONAL*"));
+		actions[PAM_SUCCESS] = _PAM_ACTION_OK;
+		actions[PAM_NEW_AUTHTOK_REQD] = _PAM_ACTION_OK;
+		_pam_set_default_control(actions, _PAM_ACTION_IGNORE);
+	    } else if (!strcasecmp("sufficient", tok)) {
+		D(("*PAM_F_SUFFICIENT*"));
+		actions[PAM_SUCCESS] = _PAM_ACTION_DONE;
+		actions[PAM_NEW_AUTHTOK_REQD] = _PAM_ACTION_DONE;
+		_pam_set_default_control(actions, _PAM_ACTION_IGNORE);
+	    } else if (!strcasecmp("include", tok)) {
+		D(("*PAM_F_INCLUDE*"));
+		pam_include = 1;
+		substack = 0;
+	    } else if (!strcasecmp("substack", tok)) {
+		D(("*PAM_F_SUBSTACK*"));
+		pam_include = 1;
+		substack = 1;
+	    } else {
+		D(("will need to parse %s", tok));
+		_pam_parse_control(actions, tok);
+		/* by default the default is to treat as failure */
+		_pam_set_default_control(actions, _PAM_ACTION_BAD);
+	    }
+
+	    tok = _pam_StrTok(NULL, " \n\t", &nexttok);
+	    if (pam_include) {
+		if (substack) {
+		    res = _pam_add_handler(pamh, PAM_HT_SUBSTACK, other,
+				stack_level, module_type, actions, tok,
+				0, NULL, 0);
+		    if (res != PAM_SUCCESS) {
+			pam_syslog(pamh, LOG_ERR, "error adding substack %s", tok);
+			D(("failed to load module - aborting"));
+			return PAM_ABORT;
+		    }
+		}
+		if (_pam_load_conf_file(pamh, tok, this_service, module_type,
+		    stack_level + substack
+#ifdef PAM_READ_BOTH_CONFS
+					      , !other
+#endif /* PAM_READ_BOTH_CONFS */
+		    ) == PAM_SUCCESS)
+		    continue;
+		_pam_set_default_control(actions, _PAM_ACTION_BAD);
+		mod_path = NULL;
+		handler_type = PAM_HT_MUST_FAIL;
+		nexttok = NULL;
+	    } else if (tok != NULL) {
+		mod_path = tok;
+		D(("mod_path = %s",mod_path));
+	    } else {
+		/* no module name given */
+		D(("_pam_init_handlers: no module name supplied"));
+		pam_syslog(pamh, LOG_ERR,
+		           "(%s) no module name supplied", this_service);
+		mod_path = NULL;
+		handler_type = PAM_HT_MUST_FAIL;
+	    }
+
+	    /* nexttok points to remaining arguments... */
+
+	    if (nexttok != NULL) {
+		D(("list: %s",nexttok));
+	        argvlen = _pam_mkargv(nexttok, &argv, &argc);
+		D(("argvlen = %d",argvlen));
+	    } else {               /* there are no arguments so fix by hand */
+		D(("_pam_init_handlers: empty argument list"));
+		argvlen = argc = 0;
+		argv = NULL;
+	    }
+
+#ifdef PAM_DEBUG
+	    {
+		int y;
+
+		D(("CONF%s: %s%s %d %s %d"
+		   , handler_type==PAM_HT_MUST_FAIL?"<*will fail*>":""
+		   , this_service, other ? "(backup)":""
+		   , module_type
+		   , mod_path, argc));
+		for (y = 0; y < argc; y++) {
+		    D(("CONF: %s", argv[y]));
+		}
+		for (y = 0; y<_PAM_RETURN_VALUES; ++y) {
+		    D(("RETURN %s(%d) -> %d %s",
+		       _pam_token_returns[y], y, actions[y],
+		       actions[y]>0 ? "jump":
+			_pam_token_actions[-actions[y]]));
+		}
+	    }
+#endif
+
+	    res = _pam_add_handler(pamh, handler_type, other, stack_level
+				   , module_type, actions, mod_path
+				   , argc, argv, argvlen);
+	    if (res != PAM_SUCCESS) {
+		pam_syslog(pamh, LOG_ERR, "error loading %s", mod_path);
+		D(("failed to load module - aborting"));
+		return PAM_ABORT;
+	    }
+	}
+    }
+
+    return ( (x < 0) ? PAM_ABORT:PAM_SUCCESS );
+}
+
+static int
+_pam_open_config_file(pam_handle_t *pamh
+			, const char *service
+			, char **path
+			, FILE **file)
+{
+    char *p;
+    FILE *f;
+    int err = 0;
+
+    /* Absolute path */
+    if (service[0] == '/') {
+	p = _pam_strdup(service);
+	if (p == NULL) {
+	    pam_syslog(pamh, LOG_CRIT, "strdup failed");
+	    return PAM_BUF_ERR;
+	}
+
+	f = fopen(service, "r");
+	if (f != NULL) {
+	    *path = p;
+	    *file = f;
+	    return PAM_SUCCESS;
+	}
+
+	_pam_drop(p);
+	return PAM_ABORT;
+    }
+
+    /* Local Machine Configuration /etc/pam.d/ */
+    if (asprintf (&p, PAM_CONFIG_DF, service) < 0) {
+	pam_syslog(pamh, LOG_CRIT, "asprintf failed");
+	return PAM_BUF_ERR;
+    }
+    D(("opening %s", p));
+    f = fopen(p, "r");
+    if (f != NULL) {
+	    *path = p;
+	    *file = f;
+	    return PAM_SUCCESS;
+    }
+
+    /* System Configuration /usr/lib/pam.d/ */
+    _pam_drop(p);
+    if (asprintf (&p, PAM_CONFIG_DIST_DF, service) < 0) {
+	pam_syslog(pamh, LOG_CRIT, "asprintf failed");
+	return PAM_BUF_ERR;
+    }
+    D(("opening %s", p));
+    f = fopen(p, "r");
+    if (f != NULL) {
+	    *path = p;
+	    *file = f;
+	    return PAM_SUCCESS;
+    }
+    _pam_drop(p);
+
+    return PAM_ABORT;
+}
+
+static int _pam_load_conf_file(pam_handle_t *pamh, const char *config_name
+				, const char *service /* specific file */
+				, int module_type /* specific type */
+				, int stack_level /* level of substack */
+#ifdef PAM_READ_BOTH_CONFS
+				, int not_other
+#endif /* PAM_READ_BOTH_CONFS */
+    )
+{
+    FILE *f;
+    char *path = NULL;
+    int retval = PAM_ABORT;
+
+    D(("_pam_load_conf_file called"));
+
+    if (stack_level >= PAM_SUBSTACK_MAX_LEVEL) {
+	D(("maximum level of substacks reached"));
+	pam_syslog(pamh, LOG_ERR, "maximum level of substacks reached");
+	return PAM_ABORT;
+    }
+
+    if (config_name == NULL) {
+	D(("no config file supplied"));
+	pam_syslog(pamh, LOG_ERR, "(%s) no config name supplied", service);
+	return PAM_ABORT;
+    }
+
+    if (_pam_open_config_file(pamh, config_name, &path, &f) == PAM_SUCCESS) {
+	retval = _pam_parse_conf_file(pamh, f, service, module_type, stack_level
+#ifdef PAM_READ_BOTH_CONFS
+					      , not_other
+#endif /* PAM_READ_BOTH_CONFS */
+	    );
+	if (retval != PAM_SUCCESS)
+	    pam_syslog(pamh, LOG_ERR,
+		       "_pam_load_conf_file: error reading %s: %s",
+		       path, pam_strerror(pamh, retval));
+	_pam_drop(path);
+	fclose(f);
+    } else {
+	D(("unable to open %s", config_name));
+	pam_syslog(pamh, LOG_ERR,
+		   "_pam_load_conf_file: unable to open config for %s",
+		   config_name);
+    }
+
+    return retval;
+}
+
+/* Parse config file, allocate handler structures, dlopen() */
+int _pam_init_handlers(pam_handle_t *pamh)
+{
+    FILE *f;
+    int retval;
+
+    D(("_pam_init_handlers called"));
+    IF_NO_PAMH("_pam_init_handlers",pamh,PAM_SYSTEM_ERR);
+
+    /* Return immediately if everything is already loaded */
+    if (pamh->handlers.handlers_loaded) {
+	return PAM_SUCCESS;
+    }
+
+    D(("_pam_init_handlers: initializing"));
+
+    /* First clean the service structure */
+
+    _pam_free_handlers(pamh);
+    if (! pamh->handlers.module) {
+	if ((pamh->handlers.module =
+	     malloc(MODULE_CHUNK * sizeof(struct loaded_module))) == NULL) {
+	    pam_syslog(pamh, LOG_CRIT,
+		       "_pam_init_handlers: no memory loading module");
+	    return PAM_BUF_ERR;
+	}
+	pamh->handlers.modules_allocated = MODULE_CHUNK;
+	pamh->handlers.modules_used = 0;
+    }
+
+    if (pamh->service_name == NULL) {
+	return PAM_BAD_ITEM;                /* XXX - better error? */
+    }
+
+#ifdef PAM_LOCKING
+    /* Is the PAM subsystem locked? */
+    {
+	 int fd_tmp;
+
+	 if ((fd_tmp = open( PAM_LOCK_FILE, O_RDONLY )) != -1) {
+	     pam_syslog(pamh, LOG_ERR,
+			"_pam_init_handlers: PAM lockfile ("
+			PAM_LOCK_FILE ") exists - aborting");
+	      (void) close(fd_tmp);
+	      /*
+	       * to avoid swamping the system with requests
+	       */
+	      _pam_start_timer(pamh);
+	      pam_fail_delay(pamh, 5000000);
+	      _pam_await_timer(pamh, PAM_ABORT);
+
+	      return PAM_ABORT;
+	 }
+    }
+#endif /* PAM_LOCKING */
+
+    /*
+     * Now parse the config file(s) and add handlers
+     */
+    {
+	struct stat test_d;
+
+	/* Is there a PAM_CONFIG_D directory? */
+	if ((stat(PAM_CONFIG_D, &test_d) == 0 && S_ISDIR(test_d.st_mode)) ||
+	    (stat(PAM_CONFIG_DIST_D, &test_d) == 0 && S_ISDIR(test_d.st_mode))) {
+	    char *path = NULL;
+	    int read_something=0;
+
+	    if (_pam_open_config_file(pamh, pamh->service_name, &path, &f) == PAM_SUCCESS) {
+		retval = _pam_parse_conf_file(pamh, f, pamh->service_name,
+		    PAM_T_ANY, 0
+#ifdef PAM_READ_BOTH_CONFS
+					      , 0
+#endif /* PAM_READ_BOTH_CONFS */
+		    );
+		if (retval != PAM_SUCCESS) {
+		    pam_syslog(pamh, LOG_ERR,
+				    "_pam_init_handlers: error reading %s",
+				    path);
+		    pam_syslog(pamh, LOG_ERR, "_pam_init_handlers: [%s]",
+				    pam_strerror(pamh, retval));
+		} else {
+		    read_something = 1;
+		}
+		_pam_drop(path);
+		fclose(f);
+	    } else {
+		D(("unable to open configuration for %s", pamh->service_name));
+#ifdef PAM_READ_BOTH_CONFS
+		D(("checking %s", PAM_CONFIG));
+
+		if ((f = fopen(PAM_CONFIG,"r")) != NULL) {
+		    retval = _pam_parse_conf_file(pamh, f, NULL, PAM_T_ANY, 0, 1);
+		    fclose(f);
+		} else
+#endif /* PAM_READ_BOTH_CONFS */
+		retval = PAM_SUCCESS;
+		/*
+		 * XXX - should we log an error? Some people want to always
+		 * use "other"
+		 */
+	    }
+
+	    if (retval == PAM_SUCCESS) {
+		/* now parse the PAM_DEFAULT_SERVICE */
+
+		if (_pam_open_config_file(pamh, PAM_DEFAULT_SERVICE, &path, &f) == PAM_SUCCESS) {
+		    /* would test magic here? */
+		    retval = _pam_parse_conf_file(pamh, f, PAM_DEFAULT_SERVICE,
+			PAM_T_ANY, 0
+#ifdef PAM_READ_BOTH_CONFS
+						  , 0
+#endif /* PAM_READ_BOTH_CONFS */
+			);
+		    if (retval != PAM_SUCCESS) {
+			pam_syslog(pamh, LOG_ERR,
+					"_pam_init_handlers: error reading %s",
+					path);
+			pam_syslog(pamh, LOG_ERR,
+					"_pam_init_handlers: [%s]",
+					pam_strerror(pamh, retval));
+		    } else {
+			read_something = 1;
+		    }
+		    _pam_drop(path);
+		    fclose(f);
+		} else {
+		    D(("unable to open %s", PAM_DEFAULT_SERVICE));
+		    pam_syslog(pamh, LOG_ERR,
+				    "_pam_init_handlers: no default config %s",
+				    PAM_DEFAULT_SERVICE);
+		}
+		if (!read_something) {          /* nothing read successfully */
+		    retval = PAM_ABORT;
+		}
+	    }
+	} else {
+	    if ((f = fopen(PAM_CONFIG, "r")) == NULL) {
+		pam_syslog(pamh, LOG_ERR, "_pam_init_handlers: could not open "
+				PAM_CONFIG );
+		return PAM_ABORT;
+	    }
+
+	    retval = _pam_parse_conf_file(pamh, f, NULL, PAM_T_ANY, 0
+#ifdef PAM_READ_BOTH_CONFS
+					  , 0
+#endif /* PAM_READ_BOTH_CONFS */
+		);
+
+	    D(("closing configuration file"));
+	    fclose(f);
+	}
+    }
+
+    if (retval != PAM_SUCCESS) {
+	/* Read error */
+	pam_syslog(pamh, LOG_ERR, "error reading PAM configuration file");
+	return PAM_ABORT;
+    }
+
+    pamh->handlers.handlers_loaded = 1;
+
+    D(("_pam_init_handlers exiting"));
+    return PAM_SUCCESS;
+}
+
+/*
+ * This is where we read a line of the PAM config file. The line may be
+ * preceeded by lines of comments and also extended with "\\\n"
+ */
+
+static int _pam_assemble_line(FILE *f, char *buffer, int buf_len)
+{
+    char *p = buffer;
+    char *endp = buffer + buf_len;
+    char *s, *os;
+    int used = 0;
+
+    /* loop broken with a 'break' when a non-'\\n' ended line is read */
+
+    D(("called."));
+    for (;;) {
+	if (p >= endp) {
+	    /* Overflow */
+	    D(("_pam_assemble_line: overflow"));
+	    return -1;
+	}
+	if (fgets(p, endp - p, f) == NULL) {
+	    if (used) {
+		/* Incomplete read */
+		return -1;
+	    } else {
+		/* EOF */
+		return 0;
+	    }
+	}
+
+	/* skip leading spaces --- line may be blank */
+
+	s = p + strspn(p, " \n\t");
+	if (*s && (*s != '#')) {
+	    os = s;
+
+	    /*
+	     * we are only interested in characters before the first '#'
+	     * character
+	     */
+
+	    while (*s && *s != '#')
+		 ++s;
+	    if (*s == '#') {
+		 *s = '\0';
+		 used += strlen(os);
+		 break;                /* the line has been read */
+	    }
+
+	    s = os;
+
+	    /*
+	     * Check for backslash by scanning back from the end of
+	     * the entered line, the '\n' has been included since
+	     * normally a line is terminated with this
+	     * character. fgets() should only return one though!
+	     */
+
+	    s += strlen(s);
+	    while (s > os && ((*--s == ' ') || (*s == '\t')
+			      || (*s == '\n')));
+
+	    /* check if it ends with a backslash */
+	    if (*s == '\\') {
+		*s++ = ' ';             /* replace backslash with ' ' */
+		*s = '\0';              /* truncate the line here */
+		used += strlen(os);
+		p = s;                  /* there is more ... */
+	    } else {
+		/* End of the line! */
+		used += strlen(os);
+		break;                  /* this is the complete line */
+	    }
+
+	} else {
+	    /* Nothing in this line */
+	    /* Don't move p         */
+	}
+    }
+
+    return used;
+}
+
+static char *
+extract_modulename(const char *mod_path)
+{
+  const char *p = strrchr (mod_path, '/');
+  char *dot, *retval;
+
+  if (p == NULL)
+    p = mod_path;
+  else
+    p++;
+
+  if ((retval = _pam_strdup (p)) == NULL)
+    return NULL;
+
+  dot = strrchr (retval, '.');
+  if (dot)
+    *dot = '\0';
+
+  if (*retval == '\0' || strcmp(retval, "?") == 0) {
+    /* do not allow empty module name or "?" to avoid confusing audit trail */
+    _pam_drop(retval);
+    return NULL;
+  }
+
+  return retval;
+}
+
+static struct loaded_module *
+_pam_load_module(pam_handle_t *pamh, const char *mod_path, int handler_type)
+{
+    int x = 0;
+    int success;
+    char *mod_full_isa_path=NULL, *isa=NULL;
+    struct loaded_module *mod;
+
+    D(("_pam_load_module: loading module `%s'", mod_path));
+
+    mod = pamh->handlers.module;
+
+    /* First, ensure the module is loaded */
+    while (x < pamh->handlers.modules_used) {
+	if (!strcmp(mod[x].name, mod_path)) {  /* case sensitive ! */
+	    break;
+	}
+	x++;
+    }
+    if (x == pamh->handlers.modules_used) {
+	/* Not found */
+	if (pamh->handlers.modules_allocated == pamh->handlers.modules_used) {
+	    /* will need more memory */
+	    void *tmp = realloc(pamh->handlers.module,
+                               (pamh->handlers.modules_allocated+MODULE_CHUNK)
+                               *sizeof(struct loaded_module));
+	    if (tmp == NULL) {
+		D(("cannot enlarge module pointer memory"));
+		pam_syslog(pamh, LOG_CRIT,
+				"realloc returned NULL in _pam_load_module");
+		return NULL;
+	    }
+	    pamh->handlers.module = tmp;
+	    pamh->handlers.modules_allocated += MODULE_CHUNK;
+	}
+	mod = &(pamh->handlers.module[x]);
+	/* Be pessimistic... */
+	success = PAM_ABORT;
+
+	D(("_pam_load_module: _pam_dlopen(%s)", mod_path));
+	mod->dl_handle = _pam_dlopen(mod_path);
+	D(("_pam_load_module: _pam_dlopen'ed"));
+	D(("_pam_load_module: dlopen'ed"));
+	if (mod->dl_handle == NULL) {
+	    if (strstr(mod_path, "$ISA")) {
+		mod_full_isa_path = malloc(strlen(mod_path) + strlen(_PAM_ISA) + 1);
+		if (mod_full_isa_path == NULL) {
+		    D(("_pam_load_module: couldn't get memory for mod_path"));
+		    pam_syslog(pamh, LOG_CRIT, "no memory for module path");
+		    success = PAM_ABORT;
+		} else {
+		    strcpy(mod_full_isa_path, mod_path);
+                    isa = strstr(mod_full_isa_path, "$ISA");
+		    if (isa) {
+		        memmove(isa + strlen(_PAM_ISA), isa + 4, strlen(isa + 4) + 1);
+		        memmove(isa, _PAM_ISA, strlen(_PAM_ISA));
+		    }
+		    mod->dl_handle = _pam_dlopen(mod_full_isa_path);
+		    _pam_drop(mod_full_isa_path);
+		}
+	    }
+	}
+	if (mod->dl_handle == NULL) {
+	    D(("_pam_load_module: _pam_dlopen(%s) failed", mod_path));
+	    if (handler_type != PAM_HT_SILENT_MODULE)
+		pam_syslog(pamh, LOG_ERR, "unable to dlopen(%s): %s", mod_path,
+		    _pam_dlerror());
+	    /* Don't abort yet; static code may be able to find function.
+	     * But defaults to abort if nothing found below... */
+	} else {
+	    D(("module added successfully"));
+	    success = PAM_SUCCESS;
+	    mod->type = PAM_MT_DYNAMIC_MOD;
+	    pamh->handlers.modules_used++;
+	}
+
+	if (success != PAM_SUCCESS) {	         /* add a malformed module */
+	    mod->dl_handle = NULL;
+	    mod->type = PAM_MT_FAULTY_MOD;
+	    pamh->handlers.modules_used++;
+	    if (handler_type != PAM_HT_SILENT_MODULE)
+		pam_syslog(pamh, LOG_ERR, "adding faulty module: %s", mod_path);
+	    success = PAM_SUCCESS;  /* We have successfully added a module */
+	}
+
+	/* indicate its name - later we will search for it by this */
+	if ((mod->name = _pam_strdup(mod_path)) == NULL) {
+	    D(("_pam_load_module: couldn't get memory for mod_path"));
+	    pam_syslog(pamh, LOG_CRIT, "no memory for module path");
+	    success = PAM_ABORT;
+	}
+
+    } else {                           /* x != pamh->handlers.modules_used */
+	mod += x;                                    /* the located module */
+	success = PAM_SUCCESS;
+    }
+    return success == PAM_SUCCESS ? mod : NULL;
+}
+
+int _pam_add_handler(pam_handle_t *pamh
+		     , int handler_type, int other, int stack_level, int type
+		     , int *actions, const char *mod_path
+		     , int argc, char **argv, int argvlen)
+{
+    struct loaded_module *mod = NULL;
+    struct handler **handler_p;
+    struct handler **handler_p2;
+    struct handlers *the_handlers;
+    const char *sym, *sym2;
+    char *mod_full_path;
+    servicefn func, func2;
+    int mod_type = PAM_MT_FAULTY_MOD;
+
+    D(("called."));
+    IF_NO_PAMH("_pam_add_handler",pamh,PAM_SYSTEM_ERR);
+
+    D(("_pam_add_handler: adding type %d, handler_type %d, module `%s'",
+	type, handler_type, mod_path));
+
+    if ((handler_type == PAM_HT_MODULE || handler_type == PAM_HT_SILENT_MODULE) &&
+	mod_path != NULL) {
+	if (mod_path[0] == '/') {
+	    mod = _pam_load_module(pamh, mod_path, handler_type);
+	} else if (asprintf(&mod_full_path, "%s%s",
+			     DEFAULT_MODULE_PATH, mod_path) >= 0) {
+	    mod = _pam_load_module(pamh, mod_full_path, handler_type);
+	    _pam_drop(mod_full_path);
+	} else {
+	    pam_syslog(pamh, LOG_CRIT, "cannot malloc full mod path");
+	    return PAM_ABORT;
+	}
+
+	if (mod == NULL) {
+	    /* if we get here with NULL it means allocation error */
+	    return PAM_ABORT;
+	}
+
+	mod_type = mod->type;
+    }
+
+    if (mod_path == NULL)
+	mod_path = UNKNOWN_MODULE;
+
+    /*
+     * At this point 'mod' points to the stored/loaded module.
+     */
+
+    /* Now define the handler(s) based on mod->dlhandle and type */
+
+    /* decide which list of handlers to use */
+    the_handlers = (other) ? &pamh->handlers.other : &pamh->handlers.conf;
+
+    handler_p = handler_p2 = NULL;
+    func = func2 = NULL;
+    sym2 = NULL;
+
+    /* point handler_p's at the root addresses of the function stacks */
+    switch (type) {
+    case PAM_T_AUTH:
+	handler_p = &the_handlers->authenticate;
+	sym = "pam_sm_authenticate";
+	handler_p2 = &the_handlers->setcred;
+	sym2 = "pam_sm_setcred";
+	break;
+    case PAM_T_SESS:
+	handler_p = &the_handlers->open_session;
+	sym = "pam_sm_open_session";
+	handler_p2 = &the_handlers->close_session;
+	sym2 = "pam_sm_close_session";
+	break;
+    case PAM_T_ACCT:
+	handler_p = &the_handlers->acct_mgmt;
+	sym = "pam_sm_acct_mgmt";
+	break;
+    case PAM_T_PASS:
+	handler_p = &the_handlers->chauthtok;
+	sym = "pam_sm_chauthtok";
+	break;
+    default:
+	/* Illegal module type */
+	D(("_pam_add_handler: illegal module type %d", type));
+	return PAM_ABORT;
+    }
+
+    /* are the modules reliable? */
+    if (mod_type != PAM_MT_DYNAMIC_MOD &&
+	 mod_type != PAM_MT_FAULTY_MOD) {
+	D(("_pam_add_handlers: illegal module library type; %d", mod_type));
+	pam_syslog(pamh, LOG_ERR,
+			"internal error: module library type not known: %s;%d",
+			sym, mod_type);
+	return PAM_ABORT;
+    }
+
+    /* now identify this module's functions - for non-faulty modules */
+
+    if ((mod_type == PAM_MT_DYNAMIC_MOD) &&
+        !(func = _pam_dlsym(mod->dl_handle, sym)) ) {
+	pam_syslog(pamh, LOG_ERR, "unable to resolve symbol: %s", sym);
+    }
+    if (sym2) {
+	if ((mod_type == PAM_MT_DYNAMIC_MOD) &&
+	    !(func2 = _pam_dlsym(mod->dl_handle, sym2)) ) {
+	    pam_syslog(pamh, LOG_ERR, "unable to resolve symbol: %s", sym2);
+	}
+    }
+
+    /* here func (and perhaps func2) point to the appropriate functions */
+
+    /* add new handler to end of existing list */
+    while (*handler_p != NULL) {
+	handler_p = &((*handler_p)->next);
+    }
+
+    if ((*handler_p = malloc(sizeof(struct handler))) == NULL) {
+	pam_syslog(pamh, LOG_CRIT, "cannot malloc struct handler #1");
+	return (PAM_ABORT);
+    }
+
+    (*handler_p)->handler_type = handler_type;
+    (*handler_p)->stack_level = stack_level;
+    (*handler_p)->func = func;
+    memcpy((*handler_p)->actions,actions,sizeof((*handler_p)->actions));
+    (*handler_p)->cached_retval = _PAM_INVALID_RETVAL;
+    (*handler_p)->cached_retval_p = &((*handler_p)->cached_retval);
+    (*handler_p)->argc = argc;
+    (*handler_p)->argv = argv;                       /* not a copy */
+    if (((*handler_p)->mod_name = extract_modulename(mod_path)) == NULL)
+	return PAM_ABORT;
+    (*handler_p)->grantor = 0;
+    (*handler_p)->next = NULL;
+
+    /* some of the modules have a second calling function */
+    if (handler_p2) {
+	/* add new handler to end of existing list */
+	while (*handler_p2) {
+	    handler_p2 = &((*handler_p2)->next);
+	}
+
+	if ((*handler_p2 = malloc(sizeof(struct handler))) == NULL) {
+	    pam_syslog(pamh, LOG_CRIT, "cannot malloc struct handler #2");
+	    return (PAM_ABORT);
+	}
+
+	(*handler_p2)->handler_type = handler_type;
+	(*handler_p2)->stack_level = stack_level;
+	(*handler_p2)->func = func2;
+	memcpy((*handler_p2)->actions,actions,sizeof((*handler_p2)->actions));
+	(*handler_p2)->cached_retval =  _PAM_INVALID_RETVAL;     /* ignored */
+	/* Note, this next entry points to the handler_p value! */
+	(*handler_p2)->cached_retval_p = &((*handler_p)->cached_retval);
+	(*handler_p2)->argc = argc;
+	if (argv) {
+	    if (((*handler_p2)->argv = malloc(argvlen)) == NULL) {
+		pam_syslog(pamh, LOG_CRIT, "cannot malloc argv for handler #2");
+		return (PAM_ABORT);
+	    }
+	    memcpy((*handler_p2)->argv, argv, argvlen);
+	} else {
+	    (*handler_p2)->argv = NULL;              /* no arguments */
+	}
+	if (((*handler_p2)->mod_name = extract_modulename(mod_path)) == NULL)
+	    return PAM_ABORT;
+	(*handler_p2)->grantor = 0;
+	(*handler_p2)->next = NULL;
+    }
+
+    D(("_pam_add_handler: returning successfully"));
+
+    return PAM_SUCCESS;
+}
+
+/* Free various allocated structures and dlclose() the libs */
+int _pam_free_handlers(pam_handle_t *pamh)
+{
+    struct loaded_module *mod;
+
+    D(("called."));
+    IF_NO_PAMH("_pam_free_handlers",pamh,PAM_SYSTEM_ERR);
+
+    mod = pamh->handlers.module;
+
+    /* Close all loaded modules */
+
+    while (pamh->handlers.modules_used) {
+	D(("_pam_free_handlers: dlclose(%s)", mod->name));
+	free(mod->name);
+	if (mod->type == PAM_MT_DYNAMIC_MOD) {
+	    _pam_dlclose(mod->dl_handle);
+	}
+	mod++;
+	pamh->handlers.modules_used--;
+    }
+
+    /* Free all the handlers */
+
+    _pam_free_handlers_aux(&(pamh->handlers.conf.authenticate));
+    _pam_free_handlers_aux(&(pamh->handlers.conf.setcred));
+    _pam_free_handlers_aux(&(pamh->handlers.conf.acct_mgmt));
+    _pam_free_handlers_aux(&(pamh->handlers.conf.open_session));
+    _pam_free_handlers_aux(&(pamh->handlers.conf.close_session));
+    _pam_free_handlers_aux(&(pamh->handlers.conf.chauthtok));
+
+    _pam_free_handlers_aux(&(pamh->handlers.other.authenticate));
+    _pam_free_handlers_aux(&(pamh->handlers.other.setcred));
+    _pam_free_handlers_aux(&(pamh->handlers.other.acct_mgmt));
+    _pam_free_handlers_aux(&(pamh->handlers.other.open_session));
+    _pam_free_handlers_aux(&(pamh->handlers.other.close_session));
+    _pam_free_handlers_aux(&(pamh->handlers.other.chauthtok));
+
+    /* no more loaded modules */
+
+    _pam_drop(pamh->handlers.module);
+
+    /* Indicate that handlers are not initialized for this pamh */
+
+    pamh->handlers.handlers_loaded = 0;
+
+    return PAM_SUCCESS;
+}
+
+void _pam_start_handlers(pam_handle_t *pamh)
+{
+    D(("called."));
+    /* NB. There is no check for a NULL pamh here, since no return
+     * value to communicate the fact!  */
+
+    /* Indicate that handlers are not initialized for this pamh */
+    pamh->handlers.handlers_loaded = 0;
+
+    pamh->handlers.modules_allocated = 0;
+    pamh->handlers.modules_used = 0;
+    pamh->handlers.module = NULL;
+
+    /* initialize the .conf and .other entries */
+
+    pamh->handlers.conf.authenticate = NULL;
+    pamh->handlers.conf.setcred = NULL;
+    pamh->handlers.conf.acct_mgmt = NULL;
+    pamh->handlers.conf.open_session = NULL;
+    pamh->handlers.conf.close_session = NULL;
+    pamh->handlers.conf.chauthtok = NULL;
+
+    pamh->handlers.other.authenticate = NULL;
+    pamh->handlers.other.setcred = NULL;
+    pamh->handlers.other.acct_mgmt = NULL;
+    pamh->handlers.other.open_session = NULL;
+    pamh->handlers.other.close_session = NULL;
+    pamh->handlers.other.chauthtok = NULL;
+}
+
+void _pam_free_handlers_aux(struct handler **hp)
+{
+    struct handler *h = *hp;
+    struct handler *last;
+
+    D(("called."));
+    while (h) {
+	last = h;
+	_pam_drop(h->argv);  /* This is all alocated in a single chunk */
+	_pam_drop(h->mod_name);
+	h = h->next;
+	memset(last, 0, sizeof(*last));
+	free(last);
+    }
+
+    *hp = NULL;
+}