mirror of
https://github.com/linux-pam/linux-pam.git
synced 2024-11-23 09:43:36 +08:00
954234f0a4
The C standard guarantees that if the argument of free() is a null pointer, no action occurs.
126 lines
2.7 KiB
C
126 lines
2.7 KiB
C
/*
|
|
* $Id$
|
|
*
|
|
* This function provides a thread safer version of getgrnam() for use
|
|
* with PAM modules that care about this sort of thing.
|
|
*
|
|
* XXX - or at least it should provide a thread-safe alternative.
|
|
*/
|
|
|
|
#include "pam_modutil_private.h"
|
|
|
|
#include <errno.h>
|
|
#include <limits.h>
|
|
#include <grp.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
|
|
static int intlen(int number)
|
|
{
|
|
int len = 2;
|
|
while (number != 0) {
|
|
number /= 10;
|
|
len++;
|
|
}
|
|
return len;
|
|
}
|
|
|
|
struct group *
|
|
pam_modutil_getgrnam(pam_handle_t *pamh, const char *group)
|
|
{
|
|
#ifdef HAVE_GETGRNAM_R
|
|
|
|
void *buffer=NULL;
|
|
size_t length = PWD_INITIAL_LENGTH;
|
|
|
|
do {
|
|
int status;
|
|
void *new_buffer;
|
|
struct group *result = NULL;
|
|
|
|
new_buffer = realloc(buffer, sizeof(struct group) + length);
|
|
if (new_buffer == NULL) {
|
|
|
|
D(("out of memory"));
|
|
|
|
/* no memory for the group - so delete the memory */
|
|
free(buffer);
|
|
return NULL;
|
|
}
|
|
buffer = new_buffer;
|
|
|
|
/* make the re-entrant call to get the grp structure */
|
|
errno = 0;
|
|
status = getgrnam_r(group, buffer,
|
|
sizeof(struct group) + (char *) buffer,
|
|
length, &result);
|
|
if (!status && (result == buffer)) {
|
|
char *data_name;
|
|
const void *ignore;
|
|
int i;
|
|
|
|
data_name = malloc(strlen("_pammodutil_getgrnam") + 1 +
|
|
strlen(group) + 1 + intlen(INT_MAX) + 1);
|
|
if ((pamh != NULL) && (data_name == NULL)) {
|
|
D(("was unable to register the data item [%s]",
|
|
pam_strerror(pamh, status)));
|
|
free(buffer);
|
|
return NULL;
|
|
}
|
|
|
|
if (pamh != NULL) {
|
|
for (i = 0; i < INT_MAX; i++) {
|
|
sprintf(data_name, "_pammodutil_getgrnam_%s_%d", group, i);
|
|
status = PAM_NO_MODULE_DATA;
|
|
if (pam_get_data(pamh, data_name, &ignore) != PAM_SUCCESS) {
|
|
status = pam_set_data(pamh, data_name,
|
|
result, pam_modutil_cleanup);
|
|
}
|
|
if (status == PAM_SUCCESS) {
|
|
break;
|
|
}
|
|
}
|
|
} else {
|
|
status = PAM_SUCCESS;
|
|
}
|
|
|
|
free(data_name);
|
|
|
|
if (status == PAM_SUCCESS) {
|
|
D(("success"));
|
|
return result;
|
|
}
|
|
|
|
D(("was unable to register the data item [%s]",
|
|
pam_strerror(pamh, status)));
|
|
|
|
free(buffer);
|
|
return NULL;
|
|
|
|
} else if (errno != ERANGE && errno != EINTR) {
|
|
/* no sense in repeating the call */
|
|
break;
|
|
}
|
|
|
|
length <<= PWD_LENGTH_SHIFT;
|
|
|
|
} while (length < PWD_ABSURD_PWD_LENGTH);
|
|
|
|
D(("grp structure took %zu bytes or so of memory",
|
|
length+sizeof(struct group)));
|
|
|
|
free(buffer);
|
|
return NULL;
|
|
|
|
#else /* ie. ifndef HAVE_GETGRNAM_R */
|
|
|
|
/*
|
|
* Sorry, there does not appear to be a reentrant version of
|
|
* getgrnam(). So, we use the standard libc function.
|
|
*/
|
|
|
|
return getgrnam(group);
|
|
|
|
#endif /* def HAVE_GETGRNAM_R */
|
|
}
|