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b55e654026
Here is a fix for the SELinux part of udev. Setfscreatecon() overrides the default labeling behavior of SELinux when creating files, so it should only be used for as short of a time as possible, around the mknod or symlink calls. Without this, the files in udev_db get the wrong label because the fscreatecon is reset after the udev_db file creation instead of before. I'm guessing the Redhat people missed this because they modify udev_db to be one big file instead of a directory of small files (at least that's what I'm told). I created selinux_resetfscreatecon() to reset the fscreatecon asap after the file/node is created. Fixed a memory leak in selinux_init. Getfscreatecon() allocates memory for the context, and the udev code was immediately setting the pointer (security_context_t is actually a typedef'ed char*) to NULL after the call regardless of success/failure. If you're wondering about the case where there's effectively a setfscreatecon(NULL), this is ok, as its used to tell SELinux to do the default labeling behavior. Renamed selinux_restore() to selinux_exit() due to the changed behavior. Fixed a couple of dbg() messages.
169 lines
3.6 KiB
C
169 lines
3.6 KiB
C
/*
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* udev_selinux.h
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*
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* Copyright (C) 2004 Daniel Walsh
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <stddef.h>
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#include <unistd.h>
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#include <string.h>
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#include <fcntl.h>
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#include <ctype.h>
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#include <limits.h>
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#include <libgen.h>
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#include <errno.h>
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#include <selinux/selinux.h>
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#include "udev_selinux.h"
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#include "logging.h"
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static security_context_t prev_scontext = NULL;
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static int is_selinux_running(void)
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{
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static int selinux_enabled = -1;
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if (selinux_enabled == -1)
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selinux_enabled = (is_selinux_enabled() > 0);
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dbg("selinux=%i", selinux_enabled);
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return selinux_enabled;
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}
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static char *get_media(const char *devname, int mode)
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{
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FILE *fp;
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char procfile[PATH_MAX];
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char mediabuf[256];
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int size;
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char *media = NULL;
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if (!(mode && S_IFBLK))
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return NULL;
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snprintf(procfile, PATH_MAX, "/proc/ide/%s/media", devname);
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procfile[PATH_MAX-1] = '\0';
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fp = fopen(procfile, "r");
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if (!fp)
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goto out;
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if (fgets(mediabuf, sizeof(mediabuf), fp) == NULL)
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goto close_out;
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size = strlen(mediabuf);
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while (size-- > 0) {
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if (isspace(mediabuf[size])) {
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mediabuf[size] = '\0';
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} else {
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break;
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}
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}
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media = strdup(mediabuf);
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info("selinux_get_media(%s)='%s'\n", devname, media);
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close_out:
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fclose(fp);
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out:
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return media;
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}
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void selinux_setfilecon(const char *file, const char *devname, unsigned int mode)
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{
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if (is_selinux_running()) {
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security_context_t scontext = NULL;
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char *media;
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int ret = -1;
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media = get_media(devname, mode);
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if (media) {
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ret = matchmediacon(media, &scontext);
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free(media);
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}
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if (ret < 0)
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if (matchpathcon(file, mode, &scontext) < 0) {
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dbg("matchpathcon(%s) failed\n", file);
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return;
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}
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if (setfilecon(file, scontext) < 0)
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dbg("setfilecon %s failed with error '%s'", file, strerror(errno));
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freecon(scontext);
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}
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}
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void selinux_setfscreatecon(const char *file, const char *devname, unsigned int mode)
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{
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if (is_selinux_running()) {
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security_context_t scontext = NULL;
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char *media;
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int ret = -1;
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media = get_media(devname, mode);
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if (media) {
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ret = matchmediacon(media, &scontext);
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free(media);
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}
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if (ret < 0)
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if (matchpathcon(file, mode, &scontext) < 0) {
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dbg("matchpathcon(%s) failed\n", file);
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return;
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}
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if (setfscreatecon(scontext) < 0)
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dbg("setfscreatecon %s failed with error '%s'", file, strerror(errno));
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freecon(scontext);
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}
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}
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void selinux_resetfscreatecon(void)
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{
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if (is_selinux_running()) {
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if (setfscreatecon(prev_scontext) < 0)
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dbg("setfscreatecon %s failed with error '%s'", file, strerror(errno));
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}
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}
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void selinux_init(void)
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{
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/*
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* record the present security context, for file-creation
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* restoration creation purposes.
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*/
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if (is_selinux_running()) {
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if (getfscreatecon(&prev_scontext) < 0) {
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dbg("getfscreatecon failed\n");
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prev_scontext = NULL;
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}
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}
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}
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void selinux_exit(void)
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{
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if (is_selinux_running() && prev_scontext) {
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freecon(prev_scontext);
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prev_scontext = NULL;
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}
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}
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