Chad Sellers wrote:
On 8/28/09 1:58 PM, "Daniel J Walsh" <dwalsh@xxxxxxxxxx> wrote:
The general idea is to relabel a disabled policy module as
policymodule.pp.disabled
Then make sure -u and -i update this name.
Rebuilding policy does not include .disabled
Listing shows disabled as disabled.
semodule -r will remove disabled modules. If you reinstall they will come
back.
# /usr/sbin/semodule -d unconfined
# /usr/sbin/semodule -l | grep unc
unconfined 3.0.1 Disabled
unconfineduser 1.0.0
# ls -lZ /etc/selinux/targeted/modules/active/modules/unconfined.pp*
-rw-------. root root staff_u:object_r:semanage_store_t:s0
/etc/selinux/targeted/modules/active/modules/unconfined.pp.disabled
# /usr/sbin/semodule -i /usr/share/selinux/targeted/unconfined.pp.bz2
# /usr/sbin/semodule -l | grep unc
unconfined 3.0.1 Disabled
unconfineduser 1.0.0
# /usr/sbin/semodule -e unconfined
# /usr/sbin/semodule -l | grep unc
unconfined 3.0.1
unconfineduser 1.0.0
This would allow an admin to disable a module and the module will stay
disabled until he enables it.
<snip>
diff --git a/libsemanage/src/direct_api.c b/libsemanage/src/direct_api.c
index f7d65eb..49a2357 100644
--- a/libsemanage/src/direct_api.c
+++ b/libsemanage/src/direct_api.c
@@ -53,6 +53,8 @@
#include "policy.h"
#include <sys/mman.h>
+static const char *DISABLESTR=".disabled";
+
static void semanage_direct_destroy(semanage_handle_t * sh);
static int semanage_direct_disconnect(semanage_handle_t * sh);
static int semanage_direct_begintrans(semanage_handle_t * sh);
@@ -66,6 +68,8 @@ static int semanage_direct_upgrade_file(semanage_handle_t *
sh, const char *modu
static int semanage_direct_install_base(semanage_handle_t * sh, char
*base_data,
size_t data_len);
static int semanage_direct_install_base_file(semanage_handle_t * sh, const
char *module_name);
+static int semanage_direct_enable(semanage_handle_t * sh, char *module_name);
+static int semanage_direct_disable(semanage_handle_t * sh, char
*module_name);
static int semanage_direct_remove(semanage_handle_t * sh, char *module_name);
static int semanage_direct_list(semanage_handle_t * sh,
semanage_module_info_t ** modinfo,
@@ -83,6 +87,8 @@ static struct semanage_policy_table direct_funcs = {
.upgrade_file = semanage_direct_upgrade_file,
.install_base = semanage_direct_install_base,
.install_base_file = semanage_direct_install_base_file,
+ .enable = semanage_direct_enable,
+ .disable = semanage_direct_disable,
.remove = semanage_direct_remove,
.list = semanage_direct_list
};
@@ -1002,6 +1008,17 @@ static int semanage_direct_commit(semanage_handle_t *
sh)
return retval;
}
+static char * get_store_name(const char *file)
+{
+ int len = strlen(file) + strlen(DISABLESTR) + 1;
+ char *storename = calloc(1, len);
+ if (! storename) return NULL;
+ snprintf(storename,len, "%s%s", file, DISABLESTR);
+ if ( access(storename, F_OK) == 0) return storename;
+ free(storename);
+ return strdup(file);
+}
+
/* Writes a module to the sandbox's module directory, overwriting any
* previous module stored within. Note that module data are not
* free()d by this function; caller is responsible for deallocating it
@@ -1019,11 +1036,20 @@ static int semanage_direct_install(semanage_handle_t *
sh,
&filename)) != 0) {
goto cleanup;
}
- if (bzip(sh, filename, data, data_len) <= 0) {
+
+ char *storename = get_store_name(filename);
+ if (!storename) {
+ ERR(sh, "Could not allocate memory");
+ retval = -1;
+ goto cleanup;
+ }
+ if (bzip(sh, storename, data, data_len) <= 0) {
Should we present some sort of warning to the user if they install/upgrade a
module that is disabled? This seems to maintain the disabled status
silently, which might confuse users (e.g. "I just installed that module, why
isn't the policy working").
Also, I see that you patched direct_install, but not direct_upgrade. So,
upgrade will try to re-enable the module if it has been disabled.
ERR(sh, "Error while writing to %s.", filename);
retval = -3;
goto cleanup;
}
+ free(storename);
+
retval = 0;
cleanup:
free(version);
@@ -1268,6 +1294,107 @@ static int
semanage_direct_install_base_file(semanage_handle_t * sh,
return retval;
}
+/* Enables a module from the sandbox. Returns 0 on success, -1 if out
+ * of memory, -2 if module not found or could not be enabled. */
+static int semanage_direct_enable(semanage_handle_t * sh, char *module_name)
+{
+ int i, retval = -1;
+ char **module_filenames = NULL;
+ int num_mod_files;
+ size_t name_len = strlen(module_name);
+ if (semanage_get_modules_names(sh, &module_filenames, &num_mod_files) ==
+ -1) {
+ return -1;
+ }
+ for (i = 0; i < num_mod_files; i++) {
+ char *base = strrchr(module_filenames[i], '/');
+ if (base == NULL) {
+ ERR(sh, "Could not read module names.");
+ retval = -2;
+ goto cleanup;
+ }
+ base++;
+ if (memcmp(module_name, base, name_len) == 0 &&
+ strcmp(base + name_len + 3, DISABLESTR) == 0) {
+ int len = strlen(module_filenames[i]) - strlen(DISABLESTR);
+ char *enabled_name = calloc(1, len+1);
+ if (!enabled_name) {
+ ERR(sh, "Could not allocate memory");
+ retval = -1;
+ goto cleanup;
+ }
+
+ strncpy(enabled_name, module_filenames[i],len);
+
+ if (rename(module_filenames[i], enabled_name) == -1) {
+ ERR(sh, "Could not enable module file %s.",
+ enabled_name);
+ retval = -2;
+ }
+ retval = 0;
+ free(enabled_name);
+ goto cleanup;
+ }
+ }
+ ERR(sh, "Module %s was not found.", module_name);
+ retval = -2; /* module not found */
+ cleanup:
+ for (i = 0; module_filenames != NULL && i < num_mod_files; i++) {
+ free(module_filenames[i]);
+ }
+ free(module_filenames);
+ return retval;
+}
+
+/* Enables a module from the sandbox. Returns 0 on success, -1 if out
+ * of memory, -2 if module not found or could not be enabled. */
+static int semanage_direct_disable(semanage_handle_t * sh, char *module_name)
+{
+ int i, retval = -1;
+ char **module_filenames = NULL;
+ int num_mod_files;
+ size_t name_len = strlen(module_name);
+ if (semanage_get_modules_names(sh, &module_filenames, &num_mod_files) ==
+ -1) {
+ return -1;
+ }
+ for (i = 0; i < num_mod_files; i++) {
+ char *base = strrchr(module_filenames[i], '/');
+ if (base == NULL) {
+ ERR(sh, "Could not read module names.");
+ retval = -2;
+ goto cleanup;
+ }
+ base++;
+ if (memcmp(module_name, base, name_len) == 0 &&
+ strcmp(base + name_len, ".pp") == 0) {
+ char disabled_name[PATH_MAX];
+ if (snprintf(disabled_name, PATH_MAX, "%s%s",
+ module_filenames[i], DISABLESTR) == PATH_MAX) {
+ ERR(sh, "Could not disable module file %s.",
+ module_filenames[i]);
+ retval = -2;
+ goto cleanup;
+ }
+ if (rename(module_filenames[i], disabled_name) == -1) {
+ ERR(sh, "Could not disable module file %s.",
+ module_filenames[i]);
+ retval = -2;
+ }
+ retval = 0;
+ goto cleanup;
+ }
+ }
+ ERR(sh, "Module %s was not found.", module_name);
+ retval = -2; /* module not found */
+ cleanup:
+ for (i = 0; module_filenames != NULL && i < num_mod_files; i++) {
+ free(module_filenames[i]);
+ }
+ free(module_filenames);
+ return retval;
+}
+
While this function does succeed in renaming a file, it does not succeed in
preventing the module from being linked in. semanage_get_modules_names()
grabs everything in the modules directory, so the disabled modules here are
still linked into the policy. A quick sesearch confirms this.
To fix this, you'll either need to modify semanage_filename_select() to
filter out files ending in .disabled or perhaps just move them from the
modules directory to a disabled_modules directory (instead of the rename).
The latter option has the advantage of not requiring filtering that could go
wrong at some point, so I would lean toward it.
Thanks,
Chad
Do you have an updated version of this?
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