From d65d8b10b0fdf3244a9e5a610d6620992b3bd725 Mon Sep 17 00:00:00 2001
From: Seraphim Mellos <mellos@ceid.upatras.gr>
Date: Fri, 1 Aug 2008 12:46:33 +0300
Subject: Completed pam_wheel

---
 modules/pam_wheel/Makefile    | 40 ++++++++++++++++++
 modules/pam_wheel/pam_wheel.c | 97 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 137 insertions(+)
 create mode 100644 modules/pam_wheel/Makefile

diff --git a/modules/pam_wheel/Makefile b/modules/pam_wheel/Makefile
new file mode 100644
index 0000000..fa4f8e4
--- /dev/null
+++ b/modules/pam_wheel/Makefile
@@ -0,0 +1,40 @@
+#
+## Copyright (c) 2008 by Seraphim Mellos.  See LICENSE.
+#
+
+include ../../Make.defs
+
+TITLE = pam_wheel
+PAM_SO_SUFFIX = 
+LIBSHARED = $(TITLE).so$(PAM_SO_SUFFIX)
+SHLIBMODE = 755
+MAN8 = $(TITLE).8
+MANMODE = 644
+#SECUREDIR = /lib/security
+#MANDIR = /usr/share/man
+#DESTDIR =
+
+
+
+PROJ = $(LIBSHARED)
+OBJS = pam_wheel.o
+
+all:
+	case "`uname -s`" in \
+	Linux)  $(MAKE) CFLAGS="$(CFLAGS)" LDFLAGS="$(LDFLAGS)" \
+			LDLIBS="$(LDLIBS)" $(PROJ);;\
+	*) 	 echo "OS not supported.";;\
+	esac
+
+$(LIBSHARED): $(OBJS) 
+	$(LD) $(LDFLAGS) $(OBJS) $(LDLIBS) -o $(LIBSHARED)
+
+.c.o:
+	$(CC) $(CFLAGS) -c $*.c
+
+
+clean:
+	$(RM) $(PROJ) *.o
+
+
+
diff --git a/modules/pam_wheel/pam_wheel.c b/modules/pam_wheel/pam_wheel.c
index e69de29..e39d106 100644
--- a/modules/pam_wheel/pam_wheel.c
+++ b/modules/pam_wheel/pam_wheel.c
@@ -0,0 +1,97 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdio.h>
+#include <string.h>
+#include <grp.h>
+#include <pwd.h>
+
+#define PAM_SM_AUTH
+
+#define PAM_OPT_ROOT_ONLY "root_only"
+
+#include <security/pam_appl.h>
+#include <security/pam_modules.h>
+#include <security/pam_mod_misc.h>
+
+PAM_EXTERN int
+pam_sm_authenticate(pam_handle_t * pamh, int flags,
+		int argc, const char * argv[]) 
+{
+	struct passwd *opwd,*tpwd;
+	struct group *group;
+	const char *orig_user, *target_user;
+	char **user_list;
+	int pam_err, member;
+
+	/* Get info for target user. Who do you want to su to ? */
+
+	if ( ( (pam_err = pam_get_user(pamh, &target_user, NULL)) != PAM_SUCCESS )
+			|| ( orig_user == NULL ) )  {
+		PAM_ERROR("Error recovering username.");	
+		return (pam_err);
+	}
+
+	if ( (tpwd = getpwnam(target_user)) == NULL ) {
+		PAM_ERROR("Could not get passwd entry for user [%s]",target_user);
+		return (PAM_SERVICE_ERR);
+	}
+	
+	if ( openpam_get_option(pamh, PAM_OPT_ROOT_ONLY) ) {
+		/* if su to non-root -> ignore */
+		if (tpwd->pw_uid != 0) 
+			return (PAM_AUTH_ERR);
+	}
+	
+	/* Get info for originating user. Who called su? */
+
+	if ( ( (pam_err = pam_get_user(pamh, &orig_user, NULL)) != PAM_SUCCESS )
+                        || ( orig_user == NULL ) )  {                                        
+	        PAM_ERROR("Error recovering username.");
+		return (pam_err);
+	}
+
+	if ( (opwd = getpwnam(orig_user)) == NULL ) {
+		PAM_ERROR("Could not get passwd entry for user [%s]",orig_user);
+		return (PAM_SERVICE_ERR);
+	}
+	
+	/* We now have all user info we need */
+
+	if ( (group = getgrnam("wheel")) == NULL ) { 
+		group = getgrgid(0); 
+	}
+	
+	/* Check wheel or group with GID 0 have any members */
+
+	if (!group || (!group->gr_mem && (opwd->pw_gid != group->gr_gid))) {
+		PAM_LOG("Group wheel or with GID 0 has no members");
+		return (PAM_AUTH_ERR);
+	}
+	/* Check user's membership to the interested groups */
+	member=0;
+	user_list = group->gr_mem; 
+	while ( !member && user_list && *(user_list) ) {
+		if (strncmp(*user_list, orig_user, strlen(orig_user)-1 ) == 0) 
+		            member=1;
+		
+		user_list++;
+	}
+	
+	if ( member || ( opwd->pw_gid == group->gr_gid ) ) { 
+		PAM_LOG("Access granted for user '%s' to user '%s'", orig_user, target_user);
+		return (PAM_SUCCESS);
+	} else { 
+		PAM_ERROR("Access denied for user '%s' to user '%s'", orig_user, target_user);
+		return (PAM_PERM_DENIED);
+	}
+}
+
+
+PAM_EXTERN int
+pam_sm_setcred(pam_handle_t *pamh , int flags ,
+                    int argc , const char *argv[])
+{
+	return (PAM_SUCCESS);
+}
+
+PAM_MODULE_ENTRY("pam_wheel");
-- 
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