diff options
Diffstat (limited to 'modules/pam_mkhomedir/mkhomedir_helper.c')
| -rw-r--r-- | modules/pam_mkhomedir/mkhomedir_helper.c | 439 |
1 files changed, 439 insertions, 0 deletions
diff --git a/modules/pam_mkhomedir/mkhomedir_helper.c b/modules/pam_mkhomedir/mkhomedir_helper.c new file mode 100644 index 0000000..582fecc --- /dev/null +++ b/modules/pam_mkhomedir/mkhomedir_helper.c @@ -0,0 +1,439 @@ +/* mkhomedir_helper - helper for pam_mkhomedir module + + Released under the GNU LGPL version 2 or later + + Copyright (c) Red Hat, Inc., 2009 + Originally written by Jason Gunthorpe <jgg@debian.org> Feb 1999 + Structure taken from pam_lastlogin by Andrew Morgan + <morgan@parc.power.net> 1996 + */ + +#include "config.h" + +#include <stdarg.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <unistd.h> +#include <pwd.h> +#include <errno.h> +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <dirent.h> +#include <syslog.h> + +#include <security/pam_ext.h> +#include <security/pam_modutil.h> + +static unsigned long u_mask = 0022; +static unsigned long home_mode = 0; +static char skeldir[BUFSIZ] = "/etc/skel"; + +/* Do the actual work of creating a home dir */ +static int +create_homedir(const struct passwd *pwd, + const char *source, const char *dest) +{ + char remark[BUFSIZ]; + DIR *d; + struct dirent *dent; + int retval = PAM_SESSION_ERR; + + /* Create the new directory */ + if (mkdir(dest, 0700) && errno != EEXIST) + { + pam_syslog(NULL, LOG_ERR, "unable to create directory %s: %m", dest); + return PAM_PERM_DENIED; + } + + /* See if we need to copy the skel dir over. */ + if ((source == NULL) || (strlen(source) == 0)) + { + retval = PAM_SUCCESS; + goto go_out; + } + + /* Scan the directory */ + d = opendir(source); + if (d == NULL) + { + pam_syslog(NULL, LOG_DEBUG, "unable to read directory %s: %m", source); + retval = PAM_PERM_DENIED; + goto go_out; + } + + for (dent = readdir(d); dent != NULL; dent = readdir(d)) + { + int srcfd; + int destfd; + int res; + struct stat st; +#ifndef PATH_MAX + char *newsource = NULL, *newdest = NULL; + /* track length of buffers */ + int nslen = 0, ndlen = 0; + int slen = strlen(source), dlen = strlen(dest); +#else + char newsource[PATH_MAX], newdest[PATH_MAX]; +#endif + + /* Skip some files.. */ + if (strcmp(dent->d_name,".") == 0 || + strcmp(dent->d_name,"..") == 0) + continue; + + /* Determine what kind of file it is. */ +#ifndef PATH_MAX + nslen = slen + strlen(dent->d_name) + 2; + + if (nslen <= 0) + { + retval = PAM_BUF_ERR; + goto go_out; + } + + if ((newsource = malloc(nslen)) == NULL) + { + retval = PAM_BUF_ERR; + goto go_out; + } + + sprintf(newsource, "%s/%s", source, dent->d_name); +#else + snprintf(newsource, sizeof(newsource), "%s/%s", source, dent->d_name); +#endif + + if (lstat(newsource, &st) != 0) +#ifndef PATH_MAX + { + free(newsource); + newsource = NULL; + continue; + } +#else + continue; +#endif + + + /* We'll need the new file's name. */ +#ifndef PATH_MAX + ndlen = dlen + strlen(dent->d_name)+2; + + if (ndlen <= 0) + { + retval = PAM_BUF_ERR; + goto go_out; + } + + if ((newdest = malloc(ndlen)) == NULL) + { + free (newsource); + retval = PAM_BUF_ERR; + goto go_out; + } + + sprintf (newdest, "%s/%s", dest, dent->d_name); +#else + snprintf (newdest, sizeof (newdest), "%s/%s", dest, dent->d_name); +#endif + + /* If it's a directory, recurse. */ + if (S_ISDIR(st.st_mode)) + { + retval = create_homedir(pwd, newsource, newdest); + +#ifndef PATH_MAX + free(newsource); newsource = NULL; + free(newdest); newdest = NULL; +#endif + + if (retval != PAM_SUCCESS) + { + closedir(d); + goto go_out; + } + continue; + } + + /* If it's a symlink, create a new link. */ + if (S_ISLNK(st.st_mode)) + { + int pointedlen = 0; +#ifndef PATH_MAX + char *pointed = NULL; + { + int size = 100; + + while (1) { + pointed = malloc(size); + if (pointed == NULL) { + free(newsource); + free(newdest); + return PAM_BUF_ERR; + } + pointedlen = readlink(newsource, pointed, size); + if (pointedlen < 0) break; + if (pointedlen < size) break; + free(pointed); + size *= 2; + } + } + if (pointedlen < 0) + free(pointed); + else + pointed[pointedlen] = 0; +#else + char pointed[PATH_MAX]; + memset(pointed, 0, sizeof(pointed)); + + pointedlen = readlink(newsource, pointed, sizeof(pointed) - 1); +#endif + + if (pointedlen >= 0) { + if(symlink(pointed, newdest) == 0) + { + if (lchown(newdest, pwd->pw_uid, pwd->pw_gid) != 0) + { + pam_syslog(NULL, LOG_DEBUG, + "unable to change perms on link %s: %m", newdest); + closedir(d); +#ifndef PATH_MAX + free(pointed); + free(newsource); + free(newdest); +#endif + return PAM_PERM_DENIED; + } + } +#ifndef PATH_MAX + free(pointed); +#endif + } +#ifndef PATH_MAX + free(newsource); newsource = NULL; + free(newdest); newdest = NULL; +#endif + continue; + } + + /* If it's not a regular file, it's probably not a good idea to create + * the new device node, FIFO, or whatever it is. */ + if (!S_ISREG(st.st_mode)) + { +#ifndef PATH_MAX + free(newsource); newsource = NULL; + free(newdest); newdest = NULL; +#endif + continue; + } + + /* Open the source file */ + if ((srcfd = open(newsource, O_RDONLY)) < 0 || fstat(srcfd, &st) != 0) + { + pam_syslog(NULL, LOG_DEBUG, + "unable to open or stat src file %s: %m", newsource); + if (srcfd >= 0) + close(srcfd); + closedir(d); + +#ifndef PATH_MAX + free(newsource); newsource = NULL; + free(newdest); newdest = NULL; +#endif + + return PAM_PERM_DENIED; + } + + /* Open the dest file */ + if ((destfd = open(newdest, O_WRONLY | O_TRUNC | O_CREAT, 0600)) < 0) + { + pam_syslog(NULL, LOG_DEBUG, + "unable to open dest file %s: %m", newdest); + close(srcfd); + closedir(d); + +#ifndef PATH_MAX + free(newsource); newsource = NULL; + free(newdest); newdest = NULL; +#endif + return PAM_PERM_DENIED; + } + + /* Set the proper ownership and permissions for the module. We make + the file a+w and then mask it with the set mask. This preserves + execute bits */ + if (fchmod(destfd, (st.st_mode | 0222) & (~u_mask)) != 0 || + fchown(destfd, pwd->pw_uid, pwd->pw_gid) != 0) + { + pam_syslog(NULL, LOG_DEBUG, + "unable to change perms on copy %s: %m", newdest); + close(srcfd); + close(destfd); + closedir(d); + +#ifndef PATH_MAX + free(newsource); newsource = NULL; + free(newdest); newdest = NULL; +#endif + + return PAM_PERM_DENIED; + } + + /* Copy the file */ + do + { + res = pam_modutil_read(srcfd, remark, sizeof(remark)); + + if (res == 0) + continue; + + if (res > 0) { + if (pam_modutil_write(destfd, remark, res) == res) + continue; + } + + /* If we get here, pam_modutil_read returned a -1 or + pam_modutil_write returned something unexpected. */ + pam_syslog(NULL, LOG_DEBUG, "unable to perform IO: %m"); + close(srcfd); + close(destfd); + closedir(d); + +#ifndef PATH_MAX + free(newsource); newsource = NULL; + free(newdest); newdest = NULL; +#endif + + return PAM_PERM_DENIED; + } + while (res != 0); + close(srcfd); + close(destfd); + +#ifndef PATH_MAX + free(newsource); newsource = NULL; + free(newdest); newdest = NULL; +#endif + + } + closedir(d); + + retval = PAM_SUCCESS; + + go_out: + + if (chmod(dest, 0777 & (~u_mask)) != 0 || + chown(dest, pwd->pw_uid, pwd->pw_gid) != 0) + { + pam_syslog(NULL, LOG_DEBUG, + "unable to change perms on directory %s: %m", dest); + return PAM_PERM_DENIED; + } + + return retval; +} + +static int +create_homedir_helper(const struct passwd *_pwd, + const char *_skeldir, const char *_homedir) +{ + int retval = PAM_SESSION_ERR; + + retval = create_homedir(_pwd, _skeldir, _homedir); + + if (chmod(_homedir, home_mode) != 0) + { + pam_syslog(NULL, LOG_DEBUG, + "unable to change perms on home directory %s: %m", _homedir); + return PAM_PERM_DENIED; + } + + return retval; +} + +static int +make_parent_dirs(char *dir, int make) +{ + int rc = PAM_SUCCESS; + char *cp = strrchr(dir, '/'); + struct stat st; + + if (!cp) + return rc; + + if (cp != dir) { + *cp = '\0'; + if (stat(dir, &st) && errno == ENOENT) + rc = make_parent_dirs(dir, 1); + *cp = '/'; + + if (rc != PAM_SUCCESS) + return rc; + } + + if (make && mkdir(dir, 0755) && errno != EEXIST) { + pam_syslog(NULL, LOG_ERR, "unable to create directory %s: %m", dir); + return PAM_PERM_DENIED; + } + + return rc; +} + +int +main(int argc, char *argv[]) +{ + struct passwd *pwd; + struct stat st; + char *eptr; + + if (argc < 2) { + fprintf(stderr, "Usage: %s <username> [<umask> [<skeldir> [<home_mode>]]]\n", argv[0]); + return PAM_SESSION_ERR; + } + + pwd = getpwnam(argv[1]); + if (pwd == NULL) { + pam_syslog(NULL, LOG_ERR, "User unknown."); + return PAM_USER_UNKNOWN; + } + + if (argc >= 3) { + errno = 0; + u_mask = strtoul(argv[2], &eptr, 0); + if (errno != 0 || *eptr != '\0') { + pam_syslog(NULL, LOG_ERR, "Bogus umask value %s", argv[2]); + return PAM_SESSION_ERR; + } + } + + if (argc >= 4) { + if (strlen(argv[3]) >= sizeof(skeldir)) { + pam_syslog(NULL, LOG_ERR, "Too long skeldir path."); + return PAM_SESSION_ERR; + } + strcpy(skeldir, argv[3]); + } + + if (argc >= 5) { + errno = 0; + home_mode = strtoul(argv[4], &eptr, 0); + if (errno != 0 || *eptr != '\0') { + pam_syslog(NULL, LOG_ERR, "Bogus home_mode value %s", argv[4]); + return PAM_SESSION_ERR; + } + } + + if (home_mode == 0) + home_mode = 0777 & ~u_mask; + + /* Stat the home directory, if something exists then we assume it is + correct and return a success */ + if (stat(pwd->pw_dir, &st) == 0) + return PAM_SUCCESS; + + if (make_parent_dirs(pwd->pw_dir, 0) != PAM_SUCCESS) + return PAM_PERM_DENIED; + + return create_homedir_helper(pwd, skeldir, pwd->pw_dir); +} |