static void *
try_dlopen(const char *modfn, int *error)
{
void *dlh;
int fd;
openpam_log(PAM_LOG_LIBDEBUG, "dlopen(%s)", modfn);
if ((fd = open(modfn, O_RDONLY)) < 0) {
if (errno != ENOENT)
openpam_log(PAM_LOG_ERROR, "%s: %m", modfn);
return (NULL);
}
if (OPENPAM_FEATURE(VERIFY_MODULE_FILE) &&
openpam_check_desc_owner_perms(modfn, fd) != 0) {
close(fd);
return (NULL);
}
if ((dlh = fdlopen(fd, RTLD_NOW)) == NULL) {
openpam_log(PAM_LOG_ERROR, "%s: %s", modfn, dlerror());
close(fd);
errno = 0;
return (NULL);
}
close(fd);
return (dlh);
}
/*
* Validate a service name.
*
* Returns a non-zero value if the argument points to a NUL-terminated
* string consisting entirely of characters in the POSIX portable filename
* character set, excluding the path separator character.
*/
static int
valid_service_name(const char *name)
{
const char *p;
if (OPENPAM_FEATURE(RESTRICT_SERVICE_NAME)) {
/* path separator not allowed */
for (p = name; *p != '\0'; ++p)
if (!is_pfcs(*p))
return (0);
} else {
/* path separator allowed */
for (p = name; *p != '\0'; ++p)
if (!is_pfcs(*p) && *p != '/')
return (0);
}
return (1);
}
/*
* Read the specified chains from the specified file.
*
* Returns 0 if the file exists but does not contain any matching lines.
*
* Returns -1 and sets errno to ENOENT if the file does not exist.
*
* Returns -1 and sets errno to some other non-zero value if the file
* exists but is unsafe or unreadable, or an I/O error occurs.
*/
static int
openpam_load_file(pam_handle_t *pamh,
const char *service,
pam_facility_t facility,
const char *filename,
openpam_style_t style)
{
FILE *f;
int ret, serrno;
/* attempt to open the file */
if ((f = fopen(filename, "r")) == NULL) {
serrno = errno;
openpam_log(errno == ENOENT ? PAM_LOG_DEBUG : PAM_LOG_ERROR,
"%s: %m", filename);
errno = serrno;
RETURNN(-1);
} else {
openpam_log(PAM_LOG_DEBUG, "found %s", filename);
}
/* verify type, ownership and permissions */
if (OPENPAM_FEATURE(VERIFY_POLICY_FILE) &&
openpam_check_desc_owner_perms(filename, fileno(f)) != 0) {
/* already logged the cause */
serrno = errno;
fclose(f);
errno = serrno;
RETURNN(-1);
}
/* parse the file */
ret = openpam_parse_chain(pamh, service, facility,
f, filename, style);
RETURNN(ret);
}
pam_module_t *
openpam_dynamic(const char *modname)
{
pam_module_t *module;
char modpath[PATH_MAX];
const char **path, *p;
int has_so, has_ver;
int dot, len;
/*
* Simple case: module name contains path separator(s)
*/
if (strchr(modname, '/') != NULL) {
/*
* Absolute paths are not allowed if RESTRICT_MODULE_NAME
* is in effect (default off). Relative paths are never
* allowed.
*/
if (OPENPAM_FEATURE(RESTRICT_MODULE_NAME) ||
modname[0] != '/') {
openpam_log(PAM_LOG_ERROR,
"invalid module name: %s", modname);
return (NULL);
}
return (try_module(modname));
}
/*
* Check for .so and version sufixes
*/
p = strchr(modname, '\0');
has_ver = has_so = 0;
while (is_digit(*p))
--p;
if (*p == '.' && *++p != '\0') {
/* found a numeric suffix */
has_ver = 1;
/* assume that .so is either present or unneeded */
has_so = 1;
} else if (*p == '\0' && p >= modname + sizeof PAM_SOEXT &&
strcmp(p - sizeof PAM_SOEXT + 1, PAM_SOEXT) == 0) {
/* found .so suffix */
has_so = 1;
}
/*
* Complicated case: search for the module in the usual places.
*/
for (path = openpam_module_path; *path != NULL; ++path) {
/*
* Assemble the full path, including the version suffix. Take
* note of where the suffix begins so we can cut it off later.
*/
if (has_ver)
len = snprintf(modpath, sizeof modpath, "%s/%s%n",
*path, modname, &dot);
else if (has_so)
len = snprintf(modpath, sizeof modpath, "%s/%s%n.%d",
*path, modname, &dot, LIB_MAJ);
else
len = snprintf(modpath, sizeof modpath, "%s/%s%s%n.%d",
*path, modname, PAM_SOEXT, &dot, LIB_MAJ);
/* check for overflow */
if (len < 0 || (unsigned int)len >= sizeof modpath) {
errno = ENOENT;
continue;
}
/* try the versioned path */
if ((module = try_module(modpath)) != NULL)
return (module);
if (errno == ENOENT && modpath[dot] != '\0') {
/* no luck, try the unversioned path */
modpath[dot] = '\0';
if ((module = try_module(modpath)) != NULL)
return (module);
}
}
/* :( */
return (NULL);
}
