security/sandbox/linux_seccomp.h
author Christian Holler <choller@mozilla.com>
Fri, 20 Sep 2013 13:37:53 +0200
changeset 148229 67fa64cde217038d28342a5af024129f9cc2bc28
parent 142351 9a57f0f347e3fdb8b6b38c07eeaa5eff5a4049be
permissions -rw-r--r--
Bug 917242 - Symbolize ASan traces in automation. r=ted

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

/* This file has been initially imported from
 * http://git.chromium.org/gitweb/?p=chromium.git;a=blob;f=sandbox/linux/seccomp-bpf/linux_seccomp.h;h=0de0259da39ecdb745e5923b9a6ff3961c13be00;hb=2362c9abea79cae475921bdeee58f9e3910d211c
 *
 * Contains code for macro for common filters from:
 * http://outflux.net/teach-seccomp/step-5/seccomp-bpf.h
 *
 * Contains code for arch_seccomp_data and arch_sigsys from:
 * http://git.chromium.org/gitweb/?p=chromium.git;a=blob;f=sandbox/linux/seccomp-bpf/sandbox_bpf.h;h=3d269916070c97b8be8938503b9b799f12d79ca6;hb=2362c9abea79cae475921bdeee58f9e3910d211c
 *
 * For more information about Seccomp, see also:
 * Documentation/prctl/seccomp_filter.txt and
 * samples/seccomp in the Linux kernel directory, for any kernel >= 3.5.0.
 */

#ifndef SANDBOX_LINUX_SECCOMP_BPF_LINUX_SECCOMP_H__
#define SANDBOX_LINUX_SECCOMP_BPF_LINUX_SECCOMP_H__

struct arch_seccomp_data {
  int      nr;
  uint32_t arch;
  uint64_t instruction_pointer;
  uint64_t args[6];
};

struct arch_sigsys {
  void         *ip;
  int          nr;
  unsigned int arch;
};

// The Seccomp2 kernel ABI is not part of older versions of glibc.
// As we can't break compilation with these versions of the library,
// we explicitly define all missing symbols.
// If we ever decide that we can now rely on system headers, the following
// include files should be enabled:
// #include <linux/audit.h>
// #include <linux/seccomp.h>

#include <asm/unistd.h>
#include <linux/filter.h>

// From <linux/elf.h> and <linux/audit.h>
// This is necessary as we can't expect recent audit headers.
#ifndef EM_ARM
#define EM_ARM    40
#endif
#ifndef EM_386
#define EM_386    3
#endif
#ifndef EM_X86_64
#define EM_X86_64 62
#endif

#ifndef __AUDIT_ARCH_64BIT
#define __AUDIT_ARCH_64BIT 0x80000000
#endif
#ifndef __AUDIT_ARCH_LE
#define __AUDIT_ARCH_LE    0x40000000
#endif
#ifndef AUDIT_ARCH_ARM
#define AUDIT_ARCH_ARM    (EM_ARM|__AUDIT_ARCH_LE)
#endif
#ifndef AUDIT_ARCH_I386
#define AUDIT_ARCH_I386   (EM_386|__AUDIT_ARCH_LE)
#endif
#ifndef AUDIT_ARCH_X86_64
#define AUDIT_ARCH_X86_64 (EM_X86_64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
#endif

// From <linux/prctl.h>
// This is necessary as we can't expect recent prctl headers.
#ifndef PR_SET_SECCOMP
#define PR_SET_SECCOMP               22
#define PR_GET_SECCOMP               21
#endif
#ifndef PR_SET_NO_NEW_PRIVS
#define PR_SET_NO_NEW_PRIVS          38
#define PR_GET_NO_NEW_PRIVS          39
#endif
#ifndef IPC_64
#define IPC_64                   0x0100
#endif

#ifndef BPF_MOD
#define BPF_MOD                    0x90
#endif
#ifndef BPF_XOR
#define BPF_XOR                    0xA0
#endif

// From <linux/seccomp.h>
// This is necessary as we can't expect recent seccomp headers.
#ifndef SECCOMP_MODE_FILTER
#define SECCOMP_MODE_DISABLED         0
#define SECCOMP_MODE_STRICT           1
#define SECCOMP_MODE_FILTER           2  // User user-supplied filter (seccomp-bpf)
#endif

#ifndef SECCOMP_RET_KILL
// Return values supported for BPF filter programs. Please note that the
// "illegal" SECCOMP_RET_INVALID is not supported by the kernel, should only
// ever be used internally, and would result in the kernel killing our process.
#define SECCOMP_RET_KILL    0x00000000U  // Kill the task immediately
#define SECCOMP_RET_INVALID 0x00010000U  // Illegal return value
#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
#define SECCOMP_RET_ACTION  0xffff0000U  // Masks for the return value
#define SECCOMP_RET_DATA    0x0000ffffU  //   sections
#else
#define SECCOMP_RET_INVALID 0x00010000U  // Illegal return value
#endif

#ifndef SYS_SECCOMP
#define SYS_SECCOMP                   1
#endif

// Impose some reasonable maximum BPF program size. Realistically, the
// kernel probably has much lower limits. But by limiting to less than
// 30 bits, we can ease requirements on some of our data types.
#define SECCOMP_MAX_PROGRAM_SIZE (1<<30)

#if defined(__i386__)
#define MIN_SYSCALL         0u
#define MAX_PUBLIC_SYSCALL  1024u
#define MAX_SYSCALL         MAX_PUBLIC_SYSCALL
#define SECCOMP_ARCH        AUDIT_ARCH_I386

#define SECCOMP_REG(_ctx, _reg) ((_ctx)->uc_mcontext.gregs[(_reg)])
#define SECCOMP_RESULT(_ctx)    SECCOMP_REG(_ctx, REG_EAX)
#define SECCOMP_SYSCALL(_ctx)   SECCOMP_REG(_ctx, REG_EAX)
#define SECCOMP_IP(_ctx)        SECCOMP_REG(_ctx, REG_EIP)
#define SECCOMP_PARM1(_ctx)     SECCOMP_REG(_ctx, REG_EBX)
#define SECCOMP_PARM2(_ctx)     SECCOMP_REG(_ctx, REG_ECX)
#define SECCOMP_PARM3(_ctx)     SECCOMP_REG(_ctx, REG_EDX)
#define SECCOMP_PARM4(_ctx)     SECCOMP_REG(_ctx, REG_ESI)
#define SECCOMP_PARM5(_ctx)     SECCOMP_REG(_ctx, REG_EDI)
#define SECCOMP_PARM6(_ctx)     SECCOMP_REG(_ctx, REG_EBP)
#define SECCOMP_NR_IDX          (offsetof(struct arch_seccomp_data, nr))
#define SECCOMP_ARCH_IDX        (offsetof(struct arch_seccomp_data, arch))
#define SECCOMP_IP_MSB_IDX      (offsetof(struct arch_seccomp_data,           \
                                          instruction_pointer) + 4)
#define SECCOMP_IP_LSB_IDX      (offsetof(struct arch_seccomp_data,           \
                                          instruction_pointer) + 0)
#define SECCOMP_ARG_MSB_IDX(nr) (offsetof(struct arch_seccomp_data, args) +   \
                                 8*(nr) + 4)
#define SECCOMP_ARG_LSB_IDX(nr) (offsetof(struct arch_seccomp_data, args) +   \
                                 8*(nr) + 0)

#elif defined(__x86_64__)
#define MIN_SYSCALL         0u
#define MAX_PUBLIC_SYSCALL  1024u
#define MAX_SYSCALL         MAX_PUBLIC_SYSCALL
#define SECCOMP_ARCH        AUDIT_ARCH_X86_64

#define SECCOMP_REG(_ctx, _reg) ((_ctx)->uc_mcontext.gregs[(_reg)])
#define SECCOMP_RESULT(_ctx)    SECCOMP_REG(_ctx, REG_RAX)
#define SECCOMP_SYSCALL(_ctx)   SECCOMP_REG(_ctx, REG_RAX)
#define SECCOMP_IP(_ctx)        SECCOMP_REG(_ctx, REG_RIP)
#define SECCOMP_PARM1(_ctx)     SECCOMP_REG(_ctx, REG_RDI)
#define SECCOMP_PARM2(_ctx)     SECCOMP_REG(_ctx, REG_RSI)
#define SECCOMP_PARM3(_ctx)     SECCOMP_REG(_ctx, REG_RDX)
#define SECCOMP_PARM4(_ctx)     SECCOMP_REG(_ctx, REG_R10)
#define SECCOMP_PARM5(_ctx)     SECCOMP_REG(_ctx, REG_R8)
#define SECCOMP_PARM6(_ctx)     SECCOMP_REG(_ctx, REG_R9)
#define SECCOMP_NR_IDX          (offsetof(struct arch_seccomp_data, nr))
#define SECCOMP_ARCH_IDX        (offsetof(struct arch_seccomp_data, arch))
#define SECCOMP_IP_MSB_IDX      (offsetof(struct arch_seccomp_data,           \
                                          instruction_pointer) + 4)
#define SECCOMP_IP_LSB_IDX      (offsetof(struct arch_seccomp_data,           \
                                          instruction_pointer) + 0)
#define SECCOMP_ARG_MSB_IDX(nr) (offsetof(struct arch_seccomp_data, args) +   \
                                 8*(nr) + 4)
#define SECCOMP_ARG_LSB_IDX(nr) (offsetof(struct arch_seccomp_data, args) +   \
                                 8*(nr) + 0)

#elif defined(__arm__) && (defined(__thumb__) || defined(__ARM_EABI__))
// ARM EABI includes "ARM private" system calls starting at |__ARM_NR_BASE|,
// and a "ghost syscall private to the kernel", cmpxchg,
// at |__ARM_NR_BASE+0x00fff0|.
// See </arch/arm/include/asm/unistd.h> in the Linux kernel.
#define MIN_SYSCALL         ((unsigned int)__NR_SYSCALL_BASE)
#define MAX_PUBLIC_SYSCALL  (MIN_SYSCALL + 1024u)
#define MIN_PRIVATE_SYSCALL ((unsigned int)__ARM_NR_BASE)
#define MAX_PRIVATE_SYSCALL (MIN_PRIVATE_SYSCALL + 16u)
#define MIN_GHOST_SYSCALL   ((unsigned int)__ARM_NR_BASE + 0xfff0u)
#define MAX_SYSCALL         (MIN_GHOST_SYSCALL + 4u)

#define SECCOMP_ARCH AUDIT_ARCH_ARM

// ARM sigcontext_t is different from i386/x86_64.
// See </arch/arm/include/asm/sigcontext.h> in the Linux kernel.
#define SECCOMP_REG(_ctx, _reg) ((_ctx)->uc_mcontext.arm_##_reg)
// ARM EABI syscall convention.
#define SECCOMP_RESULT(_ctx)    SECCOMP_REG(_ctx, r0)
#define SECCOMP_SYSCALL(_ctx)   SECCOMP_REG(_ctx, r7)
#define SECCOMP_IP(_ctx)        SECCOMP_REG(_ctx, pc)
#define SECCOMP_PARM1(_ctx)     SECCOMP_REG(_ctx, r0)
#define SECCOMP_PARM2(_ctx)     SECCOMP_REG(_ctx, r1)
#define SECCOMP_PARM3(_ctx)     SECCOMP_REG(_ctx, r2)
#define SECCOMP_PARM4(_ctx)     SECCOMP_REG(_ctx, r3)
#define SECCOMP_PARM5(_ctx)     SECCOMP_REG(_ctx, r4)
#define SECCOMP_PARM6(_ctx)     SECCOMP_REG(_ctx, r5)
#define SECCOMP_NR_IDX          (offsetof(struct arch_seccomp_data, nr))
#define SECCOMP_ARCH_IDX        (offsetof(struct arch_seccomp_data, arch))
#define SECCOMP_IP_MSB_IDX      (offsetof(struct arch_seccomp_data,           \
                                          instruction_pointer) + 4)
#define SECCOMP_IP_LSB_IDX      (offsetof(struct arch_seccomp_data,           \
                                          instruction_pointer) + 0)
#define SECCOMP_ARG_MSB_IDX(nr) (offsetof(struct arch_seccomp_data, args) +   \
                                 8*(nr) + 4)
#define SECCOMP_ARG_LSB_IDX(nr) (offsetof(struct arch_seccomp_data, args) +   \
                                 8*(nr) + 0)

#else
#error Unsupported target platform

#endif

/* Macros to common filters */
#define VALIDATE_ARCHITECTURE \
        BPF_STMT(BPF_LD+BPF_W+BPF_ABS, SECCOMP_ARCH_IDX), \
        BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, SECCOMP_ARCH, 1, 0), \
        BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL)

#define EXAMINE_SYSCALL \
        BPF_STMT(BPF_LD+BPF_W+BPF_ABS, SECCOMP_NR_IDX)

#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)

#if defined(__arm__) && (defined(__thumb__) || defined(__ARM_EABI__))
#define ALLOW_ARM_SYSCALL(name) \
        BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __ARM_NR_##name, 0, 1), \
        BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW)
#endif

#define DENY_SYSCALL(name) \
        BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __NR_##name, 0, 1), \
        BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL)

#define KILL_PROCESS \
        BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL)

#define TRAP_PROCESS \
        BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_TRAP)

#define ALLOW_PROCESS \
        BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW)

#define TRACE_PROCESS \
        BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_TRACE)

#define ERRNO_PROCESS \
        BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ERRNO)

#endif  // SANDBOX_LINUX_SECCOMP_BPF_LINUX_SECCOMP_H__