Zbigniew Jędrzejewski-Szmek
fd421c4adc
If the cleanup function returns the appropriate type, use that to reset the variable. For other functions (usually the foreign ones which return void), add an explicit value to reset to. This causes a bit of code churn, but I think it might be worth it. In a following patch static destructors will be called from a fuzzer, and this change allows them to be called multiple times. But I think such a change might help with detecting unitialized code reuse too. We hit various bugs like this, and things are more obvious when a pointer has been set to NULL. I was worried whether this change increases text size, but it doesn't seem to: -Dbuildtype=debug: before "tree-wide: return NULL from freeing functions": -rwxrwxr-x 1 zbyszek zbyszek 4117672 Feb 16 14:36 build/libsystemd.so.0.30.0* -rwxrwxr-x 1 zbyszek zbyszek 4494520 Feb 16 15:06 build/systemd* after "tree-wide: return NULL from freeing functions": -rwxrwxr-x 1 zbyszek zbyszek 4117672 Feb 16 14:36 build/libsystemd.so.0.30.0* -rwxrwxr-x 1 zbyszek zbyszek 4494576 Feb 16 15:10 build/systemd* now: -rwxrwxr-x 1 zbyszek zbyszek 4117672 Feb 16 14:36 build/libsystemd.so.0.30.0* -rwxrwxr-x 1 zbyszek zbyszek 4494640 Feb 16 15:15 build/systemd* -Dbuildtype=release: before "tree-wide: return NULL from freeing functions": -rwxrwxr-x 1 zbyszek zbyszek 5252256 Feb 14 14:47 build-rawhide/libsystemd.so.0.30.0* -rwxrwxr-x 1 zbyszek zbyszek 1834184 Feb 16 15:09 build-rawhide/systemd* after "tree-wide: return NULL from freeing functions": -rwxrwxr-x 1 zbyszek zbyszek 5252256 Feb 14 14:47 build-rawhide/libsystemd.so.0.30.0* -rwxrwxr-x 1 zbyszek zbyszek 1834184 Feb 16 15:10 build-rawhide/systemd* now: -rwxrwxr-x 1 zbyszek zbyszek 5252256 Feb 14 14:47 build-rawhide/libsystemd.so.0.30.0* -rwxrwxr-x 1 zbyszek zbyszek 1834184 Feb 16 15:16 build-rawhide/systemd* I would expect that the compiler would be able to elide the setting of a variable if the variable is never used again. And this seems to be the case: in optimized builds there is no change in size whatsoever. And the change in size in unoptimized build is negligible. Something strange is happening with size of libsystemd: it's bigger in optimized builds. Something to figure out, but unrelated to this patch.
101 lines
4.1 KiB
C
101 lines
4.1 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include <errno.h>
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#if HAVE_APPARMOR
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# include <sys/apparmor.h>
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#endif
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#include <unistd.h>
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#include "apparmor-setup.h"
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#include "apparmor-util.h"
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#include "fd-util.h"
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#include "fileio.h"
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#include "log.h"
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#include "macro.h"
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#include "string-util.h"
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#include "strv.h"
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#if HAVE_APPARMOR
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DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(aa_policy_cache *, aa_policy_cache_unref, NULL);
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DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(aa_features *, aa_features_unref, NULL);
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#endif
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int mac_apparmor_setup(void) {
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#if HAVE_APPARMOR
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_cleanup_(aa_policy_cache_unrefp) aa_policy_cache *policy_cache = NULL;
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_cleanup_(aa_features_unrefp) aa_features *features = NULL;
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const char *current_file;
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_cleanup_free_ char *current_profile = NULL, *cache_dir_path = NULL;
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int r;
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if (!mac_apparmor_use()) {
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log_debug("AppArmor either not supported by the kernel or disabled.");
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return 0;
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}
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/* To enable LSM stacking a patch to the kernel is proposed to create a
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* per-LSM subdirectory to distinguish between the LSMs. Therefore, we
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* read the file from the LSM specific directory first and only if that
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* fails the one from the generic directory.
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*/
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FOREACH_STRING(current_file, "/proc/self/attr/apparmor/current", "/proc/self/attr/current") {
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r = read_one_line_file(current_file, ¤t_profile);
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if (r == -ENOENT)
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continue;
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else if (r < 0)
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log_warning_errno(r, "Failed to read current AppArmor profile from file %s, ignoring: %m", current_file);
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else
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break;
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}
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if (!current_profile) {
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log_warning("Failed to get the current AppArmor profile of systemd from /proc/self/attr/apparmor/current or /proc/self/attr/current, ignoring.");
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return 0;
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}
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if (!streq(current_profile, "unconfined")) {
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log_debug("We are already confined in an AppArmor profile.");
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return 0;
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}
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r = aa_features_new_from_kernel(&features);
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if (r < 0) {
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log_warning_errno(errno, "Failed to get the AppArmor feature set from the kernel, ignoring: %m");
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return 0;
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}
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cache_dir_path = aa_policy_cache_dir_path_preview(features, AT_FDCWD, "/etc/apparmor/earlypolicy");
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if (!cache_dir_path) {
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log_debug_errno(errno, "Failed to get the path of the early AppArmor policy cache directory.");
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return 0;
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}
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/* aa_policy_cache_new will internally use the same path as aa_policy_cache_dir_path_preview has returned. */
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r = aa_policy_cache_new(&policy_cache, features, AT_FDCWD, "/etc/apparmor/earlypolicy", 0);
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if (r < 0) {
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if (errno == ENOENT) {
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log_debug_errno(errno, "The early AppArmor policy cache directory %s does not exist.", cache_dir_path);
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return 0;
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}
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log_warning_errno(errno, "Failed to create a new AppArmor policy cache, ignoring: %m");
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return 0;
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}
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r = aa_policy_cache_replace_all(policy_cache, NULL);
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if (r < 0) {
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log_warning_errno(errno, "Failed to load the profiles from the early AppArmor policy cache directory %s, ignoring: %m", cache_dir_path);
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return 0;
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}
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log_info("Successfully loaded all binary profiles from AppArmor early policy cache at %s.", cache_dir_path);
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r = aa_change_profile("systemd");
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if (r < 0) {
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if (errno == ENOENT)
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log_debug_errno(errno, "Failed to change to AppArmor profile 'systemd'. Please ensure that one of the binary profile files in policy cache directory %s contains a profile with that name.", cache_dir_path);
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else
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log_error_errno(errno, "Failed to change to AppArmor profile 'systemd': %m");
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return 0;
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}
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log_info("Changed to AppArmor profile systemd.");
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#endif
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return 0;
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}
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