/* 
   Unix SMB/CIFS implementation.
   Username handling
   Copyright (C) Andrew Tridgell 1992-1998
   Copyright (C) Jeremy Allison 1997-2001.
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program 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 General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"

/* internal functions */
static struct passwd *uname_string_combinations(char *s, struct passwd * (*fn) (const char *), int N);
static struct passwd *uname_string_combinations2(char *s, int offset, struct passwd * (*fn) (const char *), int N);

/*****************************************************************
 Check if a user or group name is local (this is a *local* name for
 *local* people, there's nothing for you here...).
*****************************************************************/

static BOOL name_is_local(const char *name)
{
	return !(strchr_m(name, *lp_winbind_separator()));
}

/*****************************************************************
 Splits passed user or group name to domain and user/group name parts
 Returns True if name was splitted and False otherwise.
*****************************************************************/

BOOL split_domain_and_name(const char *name, char *domain, char* username)
{
	char *p = strchr(name,*lp_winbind_separator());
	
	
	/* Parse a string of the form DOMAIN/user into a domain and a user */
	DEBUG(10,("split_domain_and_name: checking whether name |%s| local or not\n", name));
	
	if (p) {
		fstrcpy(username, p+1);
		fstrcpy(domain, name);
		domain[PTR_DIFF(p, name)] = 0;
	} else if (lp_winbind_use_default_domain()) {
		fstrcpy(username, name);
		fstrcpy(domain, lp_workgroup());
	} else {
		return False;
	}

	DEBUG(10,("split_domain_and_name: all is fine, domain is |%s| and name is |%s|\n", domain, username));
	return True;
}

/****************************************************************************
 Get a users home directory.
****************************************************************************/

char *get_user_home_dir(const char *user)
{
	struct passwd *pass;

	/* Ensure the user exists. */

	pass = Get_Pwnam(user);

	if (!pass)
		return(NULL);
	/* Return home directory from struct passwd. */

	return(pass->pw_dir);      
}


/****************************************************************************
 * A wrapper for sys_getpwnam().  The following variations are tried:
 *   - as transmitted
 *   - in all lower case if this differs from transmitted
 *   - in all upper case if this differs from transmitted
 *   - using lp_usernamelevel() for permutations.
****************************************************************************/

static struct passwd *Get_Pwnam_ret = NULL;

static struct passwd *Get_Pwnam_internals(const char *user, char *user2)
{
	struct passwd *ret = NULL;

	if (!user2 || !(*user2))
		return(NULL);

	if (!user || !(*user))
		return(NULL);

	/* Try in all lower case first as this is the most 
	   common case on UNIX systems */
	strlower(user2);
	DEBUG(5,("Trying _Get_Pwnam(), username as lowercase is %s\n",user2));
	ret = getpwnam_alloc(user2);
	if(ret)
		goto done;

	/* Try as given, if username wasn't originally lowercase */
	if(strcmp(user, user2) != 0) {
		DEBUG(5,("Trying _Get_Pwnam(), username as given is %s\n", user));
		ret = getpwnam_alloc(user);
		if(ret)
			goto done;
	}

	/* Try as uppercase, if username wasn't originally uppercase */
	strupper(user2);
	if(strcmp(user, user2) != 0) {
		DEBUG(5,("Trying _Get_Pwnam(), username as uppercase is %s\n", user2));
		ret = getpwnam_alloc(user2);
		if(ret)
			goto done;
	}

	/* Try all combinations up to usernamelevel */
	strlower(user2);
	DEBUG(5,("Checking combinations of %d uppercase letters in %s\n", lp_usernamelevel(), user2));
	ret = uname_string_combinations(user2, getpwnam_alloc, lp_usernamelevel());

done:
	DEBUG(5,("Get_Pwnam_internals %s find user [%s]!\n",ret ? "did":"didn't", user));

	/* This call used to just return the 'passwd' static buffer.
	   This could then have accidental reuse implications, so 
	   we now malloc a copy, and free it in the next use.

	   This should cause the (ab)user to segfault if it 
	   uses an old struct. 
	   
	   This is better than useing the wrong data in security
	   critical operations.

	   The real fix is to make the callers free the returned 
	   malloc'ed data.
	*/

	if (Get_Pwnam_ret) {
		passwd_free(&Get_Pwnam_ret);
	}
	
	Get_Pwnam_ret = ret;

	return ret;
}

/****************************************************************************
 Get_Pwnam wrapper without modification.
  NOTE: This with NOT modify 'user'! 
****************************************************************************/

struct passwd *Get_Pwnam(const char *user)
{
	fstring user2;
	struct passwd *ret;

	fstrcpy(user2, user);

	DEBUG(5,("Finding user %s\n", user));

	ret = Get_Pwnam_internals(user, user2);
	
	return ret;  
}

/****************************************************************************
 Check if a user is in a netgroup user list.
****************************************************************************/

static BOOL user_in_netgroup_list(const char *user, const char *ngname)
{
#ifdef HAVE_NETGROUP
	/*	static char *mydomain = NULL; */
	/* REWRITE: make thread safe if caching */
	char *mydomain = NULL;
	/*if (mydomain == NULL) */
		yp_get_default_domain(&mydomain);

	if(mydomain == NULL) {
		DEBUG(5,("Unable to get default yp domain\n"));
		return False;
	}

	DEBUG(5,("looking for user %s of domain %s in netgroup %s\n",
		user, mydomain, ngname));
	DEBUG(5,("innetgr is %s\n", innetgr(ngname, NULL, user, mydomain)
		? "TRUE" : "FALSE"));

	if (innetgr(ngname, NULL, user, mydomain))
		return (True);
#endif /* HAVE_NETGROUP */
	return False;
}

/****************************************************************************
 Check if a user is in a winbind group.
****************************************************************************/
  
static BOOL user_in_winbind_group_list(const char *user, const char *gname, BOOL *winbind_answered)
{
	int num_groups;
	int i;
 	gid_t *groups = NULL;
 	gid_t gid, gid_low, gid_high;
 	BOOL ret = False;
 
 	*winbind_answered = False;
 
	if ((gid = nametogid(gname)) == (gid_t)-1) {
 		DEBUG(0,("user_in_winbind_group_list: nametogid for group %s failed.\n",
 			gname ));
 		goto err;
 	}

	if (!lp_winbind_gid(&gid_low, &gid_high)) {
		DEBUG(4, ("winbind gid range not configured, therefore %s cannot be a winbind group\n", gname));
 		goto err;
	}

	if (gid < gid_low || gid > gid_high) {
		DEBUG(4, ("group %s is not a winbind group\n", gname));
 		goto err;
	}
 
 	/*
 	 * Get the gid's that this user belongs to.
 	 */
 
 	if ((num_groups = winbind_getgroups(user, 0, NULL)) == -1)
 		return False;
 
 	if (num_groups == 0) {
 		*winbind_answered = True;
 		return False;
 	}
 
 	if ((groups = (gid_t *)malloc(sizeof(gid_t) * num_groups )) == NULL) {
 		DEBUG(0,("user_in_winbind_group_list: malloc fail.\n"));
 		goto err;
 	}
 
 	if ((num_groups = winbind_getgroups(user, num_groups, groups)) == -1) {
 		DEBUG(0,("user_in_winbind_group_list: second winbind_getgroups call \
failed with error %s\n", strerror(errno) ));
 		goto err;
	}
 
	/*
	 * Now we have the gid list for this user - convert the gname
	 * to a gid_t via either winbind or the local UNIX lookup and do the comparison.
	 */
 
 	for (i = 0; i < num_groups; i++) {
 		if (gid == groups[i]) {
 			ret = True;
 			break;
 		}
 	}
 
 	*winbind_answered = True;
 	SAFE_FREE(groups);
 	return ret;
 
   err:
 
 	*winbind_answered = False;
 	SAFE_FREE(groups);
 	return False;
}	      
 
/****************************************************************************
 Check if a user is in a UNIX group.
****************************************************************************/
static BOOL user_in_unix_group_list(const char *user,const char *gname)
{
	struct passwd *pass = Get_Pwnam(user);
	struct sys_userlist *user_list;
	struct sys_userlist *member;
	TALLOC_CTX *mem_ctx;

	DEBUG(10,("user_in_unix_group_list: checking user %s in group %s\n", user, gname));

 	/*
 	 * We need to check the users primary group as this
 	 * group is implicit and often not listed in the group database.
 	 */
 
 	mem_ctx = talloc_init("smbgroupedit talloc");
	if (!mem_ctx) return -1;
 	if (pass) {
 		if (strequal(gname,gidtoname(mem_ctx, pass->pw_gid))) {
 			DEBUG(10,("user_in_unix_group_list: group %s is primary group.\n", gname ));
 			goto exit;
 		}
 	}
 
	user_list = get_users_in_group(gname);
 	if (user_list == NULL) {
 		DEBUG(10,("user_in_unix_group_list: no such group %s\n", gname ));
 		return False;
 	}

	for (member = user_list; member; member = member->next) {
 		DEBUG(10,("user_in_unix_group_list: checking user %s against member %s\n",
			user, member->unix_name ));
  		if (strequal(member->unix_name,user)) {
			free_userlist(user_list);
  			goto exit;
  		}
	}

	free_userlist(user_list);
	talloc_destroy(mem_ctx);
	return False;
exit:
	talloc_destroy(mem_ctx);
	return True;
}	      

/****************************************************************************
 Check if a user is in a group list. Ask winbind first, then use UNIX.
****************************************************************************/
static BOOL user_in_group_list(const char *user, const char *gname, gid_t *groups, size_t n_groups)
{
	BOOL winbind_answered = False;
	BOOL ret;
	gid_t gid;
	unsigned i;

	gid = nametogid(gname);
	if (gid == (gid_t)-1) 
		return False;

	if (groups && n_groups > 0) {
		for (i=0; i < n_groups; i++) {
			if (groups[i] == gid) {
				return True;
			}
		}
		return False;
	}

	/* fallback if we don't yet have the group list */

	ret = user_in_winbind_group_list(user, gname, &winbind_answered);
	if (!winbind_answered)
		ret = user_in_unix_group_list(user, gname);

	if (ret)
		DEBUG(10,("user_in_group_list: user |%s| is in group |%s|\n", user, gname));
	return ret;
}

/****************************************************************************
 Check if a user is in a user list - can check combinations of UNIX
 and netgroup lists.
****************************************************************************/

BOOL user_in_list(const char *user,const char **list, gid_t *groups, size_t n_groups)
{
	if (!list || !*list)
		return False;

	DEBUG(10,("user_in_list: checking user %s in list\n", user));

	while (*list) {

		DEBUG(10,("user_in_list: checking user |%s| against |%s|\n", user, *list));

		/*
		 * Check raw username.
		 */
		if (strequal(user, *list))
			return(True);

		/*
		 * Now check to see if any combination
		 * of UNIX and netgroups has been specified.
		 */

		if(**list == '@') {
			/*
			 * Old behaviour. Check netgroup list
			 * followed by UNIX list.
			 */
			if(user_in_netgroup_list(user, *list +1))
				return True;
			if(user_in_group_list(user, *list +1, groups, n_groups))
				return True;
		} else if (**list == '+') {

			if((*(*list +1)) == '&') {
				/*
				 * Search UNIX list followed by netgroup.
				 */
				if(user_in_group_list(user, *list +2, groups, n_groups))
					return True;
				if(user_in_netgroup_list(user, *list +2))
					return True;

			} else {

				/*
				 * Just search UNIX list.
				 */

				if(user_in_group_list(user, *list +1, groups, n_groups))
					return True;
			}

		} else if (**list == '&') {

			if(*(*list +1) == '+') {
				/*
				 * Search netgroup list followed by UNIX list.
				 */
				if(user_in_netgroup_list(user, *list +2))
					return True;
				if(user_in_group_list(user, *list +2, groups, n_groups))
					return True;
			} else {
				/*
				 * Just search netgroup list.
				 */
				if(user_in_netgroup_list(user, *list +1))
					return True;
			}
		} else if (!name_is_local(*list)) {
			/*
			 * If user name did not match and token is not
			 * a unix group and the token has a winbind separator in the
			 * name then see if it is a Windows group.
			 */

			DOM_SID g_sid;
			enum SID_NAME_USE name_type;
			BOOL winbind_answered = False;
			BOOL ret;
			fstring groupname, domain;
			
			/* Parse a string of the form DOMAIN/user into a domain and a user */

			char *p = strchr(*list,*lp_winbind_separator());
			
			DEBUG(10,("user_in_list: checking if user |%s| is in winbind group |%s|\n", user, *list));

			if (p) {
				fstrcpy(groupname, p+1);
				fstrcpy(domain, *list);
				domain[PTR_DIFF(p, *list)] = 0;

				/* Check to see if name is a Windows group */
				if (winbind_lookup_name(domain, groupname, &g_sid, &name_type) && name_type == SID_NAME_DOM_GRP) {
					
				/* Check if user name is in the Windows group */
					ret = user_in_winbind_group_list(user, *list, &winbind_answered);
					
					if (winbind_answered && ret == True) {
						DEBUG(10,("user_in_list: user |%s| is in winbind group |%s|\n", user, *list));
						return ret;
					}
				}
			}
		}
    
		list++;
	}
	return(False);
}

/* The functions below have been taken from password.c and slightly modified */
/****************************************************************************
 Apply a function to upper/lower case combinations
 of a string and return true if one of them returns true.
 Try all combinations with N uppercase letters.
 offset is the first char to try and change (start with 0)
 it assumes the string starts lowercased
****************************************************************************/

static struct passwd *uname_string_combinations2(char *s,int offset,struct passwd *(*fn)(const char *),int N)
{
	ssize_t len = (ssize_t)strlen(s);
	int i;
	struct passwd *ret;

	if (N <= 0 || offset >= len)
		return(fn(s));

	for (i=offset;i<(len-(N-1));i++) {
		char c = s[i];
		if (!islower((int)c))
			continue;
		s[i] = toupper(c);
		ret = uname_string_combinations2(s,i+1,fn,N-1);
		if(ret)
			return(ret);
		s[i] = c;
	}
	return(NULL);
}

/****************************************************************************
 Apply a function to upper/lower case combinations
 of a string and return true if one of them returns true.
 Try all combinations with up to N uppercase letters.
 offset is the first char to try and change (start with 0)
 it assumes the string starts lowercased
****************************************************************************/

static struct passwd * uname_string_combinations(char *s,struct passwd * (*fn)(const char *),int N)
{
	int n;
	struct passwd *ret;

	for (n=1;n<=N;n++) {
		ret = uname_string_combinations2(s,0,fn,n);
		if(ret)
			return(ret);
	}  
	return(NULL);
}