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Code

core/bpf: lsm_bpf_supported() returns a boolean

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The code was corret, but confusing, because it was treating the int
as a boolean.

(cherry picked from commit 389db516df)
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2022-05-17 10:11:05 +02:00
parent 6f8adbad80
commit 9d6fa4e17d
3 changed files with 13 additions and 14 deletions
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22
src/core/bpf-lsm.c
View File

@ -125,7 +125,7 @@ static int mac_bpf_use(void) {
}
}
int lsm_bpf_supported(void) {
bool lsm_bpf_supported(void) {
_cleanup_(restrict_fs_bpf_freep) struct restrict_fs_bpf *obj = NULL;
static int supported = -1;
int r;
@ -136,44 +136,44 @@ int lsm_bpf_supported(void) {
r = dlopen_bpf();
if (r < 0) {
log_info_errno(r, "Failed to open libbpf, LSM BPF is not supported: %m");
return supported = 0;
return (supported = false);
}
r = cg_unified_controller(SYSTEMD_CGROUP_CONTROLLER);
if (r < 0) {
log_warning_errno(r, "Can't determine whether the unified hierarchy is used: %m");
return supported = 0;
return (supported = false);
}
if (r == 0) {
log_info_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
"Not running with unified cgroup hierarchy, LSM BPF is not supported");
return supported = 0;
return (supported = false);
}
r = mac_bpf_use();
if (r < 0) {
log_warning_errno(r, "Can't determine whether the BPF LSM module is used: %m");
return supported = 0;
return (supported = false);
}
if (r == 0) {
log_info_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
"BPF LSM hook not enabled in the kernel, LSM BPF not supported");
return supported = 0;
return (supported = false);
}
r = prepare_restrict_fs_bpf(&obj);
if (r < 0)
return supported = 0;
return (supported = false);
if (!bpf_can_link_lsm_program(obj->progs.restrict_filesystems)) {
log_warning_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
"Failed to link BPF program. Assuming BPF is not available");
return supported = 0;
return (supported = false);
}
return supported = 1;
return (supported = true);
}
int lsm_bpf_setup(Manager *m) {
@ -297,8 +297,8 @@ void lsm_bpf_destroy(struct restrict_fs_bpf *prog) {
restrict_fs_bpf__destroy(prog);
}
#else /* ! BPF_FRAMEWORK */
int lsm_bpf_supported(void) {
return 0;
bool lsm_bpf_supported(void) {
return false;
}
int lsm_bpf_setup(Manager *m) {

2
src/core/bpf-lsm.h
View File

@ -14,7 +14,7 @@ typedef struct Manager Manager;
typedef struct restrict_fs_bpf restrict_fs_bpf;
int lsm_bpf_supported(void);
bool lsm_bpf_supported(void);
int lsm_bpf_setup(Manager *m);
int lsm_bpf_unit_restrict_filesystems(Unit *u, const Set *filesystems, bool allow_list);
int lsm_bpf_cleanup(const Unit *u);

3
src/test/test-bpf-lsm.c
View File

@ -81,8 +81,7 @@ int main(int argc, char *argv[]) {
if (!can_memlock())
return log_tests_skipped("Can't use mlock(), skipping.");
r = lsm_bpf_supported();
if (r <= 0)
if (!lsm_bpf_supported())
return log_tests_skipped("LSM BPF hooks are not supported");
r = enter_cgroup_subroot(NULL);