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SELinuxMeter: improve SELinux detection in constrained environments #1980

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Merged
BenBE merged 1 commit into from
May 3, 2026
+24 −16
Merged

SELinuxMeter: improve SELinux detection in constrained environments #1980

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40 changes: 24 additions & 16 deletions linux/SELinuxMeter.c
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@ in the source distribution for its full text.

#include "CRT.h"

#include <errno.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
Expand All @@ -27,8 +28,19 @@ static const int SELinuxMeter_attributes[] = {
METER_TEXT,
};

static bool enabled = false;
static bool enforcing = false;
typedef enum {
SELINUX_PERMISSIVE,
SELINUX_ENFORCING,
SELINUX_UNKNOWN,
SELINUX_DISABLED,
} EnforcingMode;

static const char* const enforcingText[] = {
[SELINUX_PERMISSIVE] = "enabled; mode: permissive",
[SELINUX_ENFORCING] = "enabled; mode: enforcing",
[SELINUX_UNKNOWN] = "enabled; mode: unknown",
[SELINUX_DISABLED] = "disabled",
};

static bool hasSELinuxMount(void) {
struct statfs sfbuf;
Expand All @@ -51,32 +63,28 @@ static bool hasSELinuxMount(void) {
}

static bool isSelinuxEnabled(void) {
return hasSELinuxMount() && (0 == access("/etc/selinux/config", F_OK));
return hasSELinuxMount();
}

static bool isSelinuxEnforcing(void) {
if (!enabled) {
return false;
}
static EnforcingMode getSelinuxEnforcing(void) {
if (!isSelinuxEnabled())
return SELINUX_DISABLED;

char buf[20];
ssize_t r = Compat_readfile("/sys/fs/selinux/enforce", buf, sizeof(buf));
if (r < 0)
return false;
return (r == -ENOENT) ? SELINUX_DISABLED : SELINUX_UNKNOWN;

int enforce = 0;
if (sscanf(buf, "%d", &enforce) != 1) {
return false;
}
if (sscanf(buf, "%d", &enforce) != 1)
return SELINUX_UNKNOWN;

return !!enforce;
return enforce ? SELINUX_ENFORCING : SELINUX_PERMISSIVE;
}

static void SELinuxMeter_updateValues(Meter* this) {
enabled = isSelinuxEnabled();
enforcing = isSelinuxEnforcing();

xSnprintf(this->txtBuffer, sizeof(this->txtBuffer), "%s%s", enabled ? "enabled" : "disabled", enabled ? (enforcing ? "; mode: enforcing" : "; mode: permissive") : "");
EnforcingMode enforcing = getSelinuxEnforcing();
xSnprintf(this->txtBuffer, sizeof(this->txtBuffer), "%s", enforcingText[enforcing]);
}

const MeterClass SELinuxMeter_class = {
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