diff options
Diffstat (limited to 'src/shared/linux')
| -rw-r--r-- | src/shared/linux/seccomp-bpf.h | 76 | ||||
| -rw-r--r-- | src/shared/linux/seccomp.h | 47 |
2 files changed, 123 insertions, 0 deletions
diff --git a/src/shared/linux/seccomp-bpf.h b/src/shared/linux/seccomp-bpf.h new file mode 100644 index 0000000000..1e3d136739 --- /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_ */ diff --git a/src/shared/linux/seccomp.h b/src/shared/linux/seccomp.h new file mode 100644 index 0000000000..9c03683fa0 --- /dev/null +++ b/src/shared/linux/seccomp.h @@ -0,0 +1,47 @@ +#ifndef _LINUX_SECCOMP_H +#define _LINUX_SECCOMP_H + + +#include <linux/types.h> + + +/* Valid values for seccomp.mode and prctl(PR_SET_SECCOMP, <mode>) */ +#define SECCOMP_MODE_DISABLED 0 /* seccomp is not in use. */ +#define SECCOMP_MODE_STRICT 1 /* uses hard-coded filter. */ +#define SECCOMP_MODE_FILTER 2 /* uses user-supplied filter. */ + +/* + * All BPF programs must return a 32-bit value. + * The bottom 16-bits are for optional return data. + * The upper 16-bits are ordered from least permissive values to most. + * + * The ordering ensures that a min_t() over composed return values always + * selects the least permissive choice. + */ +#define SECCOMP_RET_KILL 0x00000000U /* kill the task immediately */ +#define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */ +#define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */ +#define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */ +#define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */ + +/* Masks for the return value sections. */ +#define SECCOMP_RET_ACTION 0x7fff0000U +#define SECCOMP_RET_DATA 0x0000ffffU + +/** + * struct seccomp_data - the format the BPF program executes over. + * @nr: the system call number + * @arch: indicates system call convention as an AUDIT_ARCH_* value + * as defined in <linux/audit.h>. + * @instruction_pointer: at the time of the system call. + * @args: up to 6 system call arguments always stored as 64-bit values + * regardless of the architecture. + */ +struct seccomp_data { + int nr; + __u32 arch; + __u64 instruction_pointer; + __u64 args[6]; +}; + +#endif /* _LINUX_SECCOMP_H */ |