mirrors/apparmor
1
0
Fork 0
mirror of https://gitlab.com/apparmor/apparmor.git synced 2025-03-04 08:24:42 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions

Thorsten Kukuk (kukuk@suse.de) pointed out a couple problems with

Browse source 
pam_apparmor and here's a patch to address most of them--

 * header comment was incorrect
 * use pam_get_user() instead of pam_get_item()
 * return an error if we're unable to change to the DEFAULT hat

In addition, this has a fix to make sure that the magic token we read
from /dev/urandom is not null (which would cause the hat probing to fail 
if we need to fall back to the DEFAULT hat).
This commit is contained in:
Jesse Michael 2006-09-14 12:44:01 +00:00
parent 16ede09541
commit 4f4a56859e
1 changed files with 23 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

34
changehat/pam_apparmor/pam_apparmor.c
View file

@ -1,12 +1,13 @@
/* pam_apparmor module */
/*
* Modified for pam_motd by Ben Collins <bcollins@debian.org>
*
* Based off of:
* $Id$
*
* Written by Michael K. Johnson <johnsonm@redhat.com> 1996/10/24
* Written by Jesse Michael <jmichael@suse.de> 2006/08/24
*
* Based off of pam_motd by:
* Ben Collins <bcollins@debian.org> 2005/10/04
* Michael K. Johnson <johnsonm@redhat.com> 1996/10/24
*
*/
@ -20,6 +21,7 @@
#include <pwd.h>
#include <security/_pam_macros.h>
/*
* here, we make a definition for the externally accessible function
* in this file (this definition is required for static a module
@ -44,13 +46,13 @@ PAM_EXTERN
int pam_sm_open_session(pam_handle_t *pamh, int flags,
int argc, const char **argv)
{
int fd, retval = PAM_IGNORE;
unsigned int magic_token = 0xDEADC0ED;
const void *user;
int fd, retval;
unsigned int magic_token;
const char *user;
/* grab the target user name */
retval = pam_get_item(pamh, PAM_USER, &user);
if (retval != PAM_SUCCESS || user == NULL || *(const char *)user == '\0') {
retval = pam_get_user(pamh, &user, NULL);
if (retval != PAM_SUCCESS || user == NULL || *user == '\0') {
return PAM_USER_UNKNOWN;
}
@ -58,7 +60,15 @@ int pam_sm_open_session(pam_handle_t *pamh, int flags,
if (fd < 0) {
return PAM_PERM_DENIED;
}
retval = read(fd, (void *) &magic_token, sizeof(magic_token));
/* the magic token needs to be non-zero otherwise, we won't be able to
probe for hats */
do {
retval = read(fd, (void *) &magic_token, sizeof(magic_token));
if (retval < 0) {
return PAM_PERM_DENIED;
}
} while (magic_token == 0);
close(fd);
@ -74,11 +84,13 @@ int pam_sm_open_session(pam_handle_t *pamh, int flags,
/* failed to change into default hat, so we'll
jump back out */
retval = change_hat(NULL, magic_token);
return PAM_PERM_DENIED;
}
}
}
/* zero out the magic token so we can't get back out */
/* zero out the magic token so an attacker wouldn't be able to just grab
it out of process memory and instead would need to brute force it */
memset(&magic_token, 0, sizeof(magic_token));
return PAM_SUCCESS;