execute: support syscall filtering using seccomp filters

[elogind.git] / src / shared / linux / seccomp-bpf.h

diff --git a/src/shared/linux/seccomp-bpf.h b/src/shared/linux/seccomp-bpf.h
new file mode 100644 (file)
index 0000000..1e3d136
--- /dev/null
+++ b/src/shared/linux/seccomp-bpf.h
@@ -0,0 +1,76 @@
+/*
+ * seccomp example for x86 (32-bit and 64-bit) with BPF macros
+ *
+ * Copyright (c) 2012 The Chromium OS Authors <chromium-os-dev@chromium.org>
+ * Authors:
+ *  Will Drewry <wad@chromium.org>
+ *  Kees Cook <keescook@chromium.org>
+ *
+ * The code may be used by anyone for any purpose, and can serve as a
+ * starting point for developing applications using mode 2 seccomp.
+ */
+#ifndef _SECCOMP_BPF_H_
+#define _SECCOMP_BPF_H_
+
+#include <stdio.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/prctl.h>
+
+#include <linux/unistd.h>
+#include <linux/audit.h>
+#include <linux/filter.h>
+#include <linux/seccomp.h>
+
+#ifndef SECCOMP_MODE_FILTER
+# define SECCOMP_MODE_FILTER   2 /* uses user-supplied filter. */
+# define SECCOMP_RET_KILL      0x00000000U /* kill the task immediately */
+# define SECCOMP_RET_TRAP      0x00030000U /* disallow and force a SIGSYS */
+# define SECCOMP_RET_ALLOW     0x7fff0000U /* allow */
+struct seccomp_data {
+    int nr;
+    __u32 arch;
+    __u64 instruction_pointer;
+    __u64 args[6];
+};
+#endif
+#ifndef SYS_SECCOMP
+# define SYS_SECCOMP 1
+#endif
+
+#define syscall_nr (offsetof(struct seccomp_data, nr))
+#define arch_nr (offsetof(struct seccomp_data, arch))
+
+#if defined(__i386__)
+# define REG_SYSCALL   REG_EAX
+# define ARCH_NR       AUDIT_ARCH_I386
+#elif defined(__x86_64__)
+# define REG_SYSCALL   REG_RAX
+# define ARCH_NR       AUDIT_ARCH_X86_64
+#else
+# warning "Platform does not support seccomp filter yet"
+# define REG_SYSCALL   0
+# define ARCH_NR       0
+#endif
+
+#define VALIDATE_ARCHITECTURE \
+       BPF_STMT(BPF_LD+BPF_W+BPF_ABS, arch_nr), \
+       BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, ARCH_NR, 1, 0), \
+       BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL)
+
+#define EXAMINE_SYSCALL \
+       BPF_STMT(BPF_LD+BPF_W+BPF_ABS, syscall_nr)
+
+#define ALLOW_SYSCALL(name) \
+       BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __NR_##name, 0, 1), \
+       BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW)
+
+#define _KILL_PROCESS \
+       BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL)
+
+#endif /* _SECCOMP_BPF_H_ */