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[tor-commits] [tor/maint-0.3.5] Merge branch 'bug28183_029' into maint-0.3.5



commit 021187f91503814f13dd73b9ed835c20c57f945d
Merge: 6f2151be9 0e5378fee
Author: Nick Mathewson <nickm@xxxxxxxxxxxxxx>
Date:   Tue Nov 13 16:48:21 2018 -0500

    Merge branch 'bug28183_029' into maint-0.3.5

 changes/bug28183          | 4 ++++
 src/lib/sandbox/sandbox.c | 2 ++
 2 files changed, 6 insertions(+)

diff --cc src/lib/sandbox/sandbox.c
index 48e37ba12,000000000..6f074bb4e
mode 100644,000000..100644
--- a/src/lib/sandbox/sandbox.c
+++ b/src/lib/sandbox/sandbox.c
@@@ -1,1806 -1,0 +1,1808 @@@
 +/* Copyright (c) 2001 Matej Pfajfar.
 + * Copyright (c) 2001-2004, Roger Dingledine.
 + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
 + * Copyright (c) 2007-2018, The Tor Project, Inc. */
 +/* See LICENSE for licensing information */
 +
 +/**
 + * \file sandbox.c
 + * \brief Code to enable sandboxing.
 + **/
 +
 +#include "orconfig.h"
 +
 +#ifndef _LARGEFILE64_SOURCE
 +/**
 + * Temporarily required for O_LARGEFILE flag. Needs to be removed
 + * with the libevent fix.
 + */
 +#define _LARGEFILE64_SOURCE
 +#endif /* !defined(_LARGEFILE64_SOURCE) */
 +
 +/** Malloc mprotect limit in bytes.
 + *
 + * 28/06/2017: This value was increased from 16 MB to 20 MB after we introduced
 + * LZMA support in Tor (0.3.1.1-alpha). We limit our LZMA coder to 16 MB, but
 + * liblzma have a small overhead that we need to compensate for to avoid being
 + * killed by the sandbox.
 + */
 +#define MALLOC_MP_LIM (20*1024*1024)
 +
 +#include <stdio.h>
 +#include <string.h>
 +#include <stdlib.h>
 +#include <errno.h>
 +
 +#include "lib/sandbox/sandbox.h"
 +#include "lib/container/map.h"
 +#include "lib/err/torerr.h"
 +#include "lib/log/log.h"
 +#include "lib/cc/torint.h"
 +#include "lib/net/resolve.h"
 +#include "lib/malloc/malloc.h"
 +#include "lib/string/scanf.h"
 +
 +#include "tor_queue.h"
 +#include "ht.h"
 +#include "siphash.h"
 +
 +#define DEBUGGING_CLOSE
 +
 +#if defined(USE_LIBSECCOMP)
 +
 +#include <sys/mman.h>
 +#include <sys/syscall.h>
 +#include <sys/types.h>
 +#include <sys/stat.h>
 +#include <sys/epoll.h>
 +#include <sys/prctl.h>
 +#include <linux/futex.h>
 +#include <sys/file.h>
 +
 +#include <stdarg.h>
 +#include <seccomp.h>
 +#include <signal.h>
 +#include <unistd.h>
 +#include <fcntl.h>
 +#include <time.h>
 +#include <poll.h>
 +
 +#ifdef HAVE_GNU_LIBC_VERSION_H
 +#include <gnu/libc-version.h>
 +#endif
 +#ifdef HAVE_LINUX_NETFILTER_IPV4_H
 +#include <linux/netfilter_ipv4.h>
 +#endif
 +#ifdef HAVE_LINUX_IF_H
 +#include <linux/if.h>
 +#endif
 +#ifdef HAVE_LINUX_NETFILTER_IPV6_IP6_TABLES_H
 +#include <linux/netfilter_ipv6/ip6_tables.h>
 +#endif
 +
 +#if defined(HAVE_EXECINFO_H) && defined(HAVE_BACKTRACE) && \
 +  defined(HAVE_BACKTRACE_SYMBOLS_FD) && defined(HAVE_SIGACTION)
 +#define USE_BACKTRACE
 +#define EXPOSE_CLEAN_BACKTRACE
 +#include "lib/err/backtrace.h"
 +#endif /* defined(HAVE_EXECINFO_H) && defined(HAVE_BACKTRACE) && ... */
 +
 +#ifdef USE_BACKTRACE
 +#include <execinfo.h>
 +#endif
 +
 +/**
 + * Linux 32 bit definitions
 + */
 +#if defined(__i386__)
 +
 +#define REG_SYSCALL REG_EAX
 +#define M_SYSCALL gregs[REG_SYSCALL]
 +
 +/**
 + * Linux 64 bit definitions
 + */
 +#elif defined(__x86_64__)
 +
 +#define REG_SYSCALL REG_RAX
 +#define M_SYSCALL gregs[REG_SYSCALL]
 +
 +#elif defined(__arm__)
 +
 +#define M_SYSCALL arm_r7
 +
 +#elif defined(__aarch64__) && defined(__LP64__)
 +
 +#define REG_SYSCALL 8
 +#define M_SYSCALL regs[REG_SYSCALL]
 +
 +#endif /* defined(__i386__) || ... */
 +
 +/**Determines if at least one sandbox is active.*/
 +static int sandbox_active = 0;
 +/** Holds the parameter list configuration for the sandbox.*/
 +static sandbox_cfg_t *filter_dynamic = NULL;
 +
 +#undef SCMP_CMP
 +#define SCMP_CMP(a,b,c) ((struct scmp_arg_cmp){(a),(b),(c),0})
 +#define SCMP_CMP_STR(a,b,c) \
 +  ((struct scmp_arg_cmp) {(a),(b),(intptr_t)(void*)(c),0})
 +#define SCMP_CMP4(a,b,c,d) ((struct scmp_arg_cmp){(a),(b),(c),(d)})
 +/* We use a wrapper here because these masked comparisons seem to be pretty
 + * verbose. Also, it's important to cast to scmp_datum_t before negating the
 + * mask, since otherwise the negation might get applied to a 32 bit value, and
 + * the high bits of the value might get masked out improperly. */
 +#define SCMP_CMP_MASKED(a,b,c) \
 +  SCMP_CMP4((a), SCMP_CMP_MASKED_EQ, ~(scmp_datum_t)(b), (c))
 +
 +/** Variable used for storing all syscall numbers that will be allowed with the
 + * stage 1 general Tor sandbox.
 + */
 +static int filter_nopar_gen[] = {
 +    SCMP_SYS(access),
 +    SCMP_SYS(brk),
 +    SCMP_SYS(clock_gettime),
 +    SCMP_SYS(close),
 +    SCMP_SYS(clone),
 +    SCMP_SYS(epoll_create),
 +    SCMP_SYS(epoll_wait),
 +#ifdef __NR_epoll_pwait
 +    SCMP_SYS(epoll_pwait),
 +#endif
 +#ifdef HAVE_EVENTFD
 +    SCMP_SYS(eventfd2),
 +#endif
 +#ifdef HAVE_PIPE2
 +    SCMP_SYS(pipe2),
 +#endif
 +#ifdef HAVE_PIPE
 +    SCMP_SYS(pipe),
 +#endif
 +#ifdef __NR_fchmod
 +    SCMP_SYS(fchmod),
 +#endif
 +    SCMP_SYS(fcntl),
 +    SCMP_SYS(fstat),
 +#ifdef __NR_fstat64
 +    SCMP_SYS(fstat64),
 +#endif
 +    SCMP_SYS(futex),
 +    SCMP_SYS(getdents),
 +    SCMP_SYS(getdents64),
 +    SCMP_SYS(getegid),
 +#ifdef __NR_getegid32
 +    SCMP_SYS(getegid32),
 +#endif
 +    SCMP_SYS(geteuid),
 +#ifdef __NR_geteuid32
 +    SCMP_SYS(geteuid32),
 +#endif
 +    SCMP_SYS(getgid),
 +#ifdef __NR_getgid32
 +    SCMP_SYS(getgid32),
 +#endif
 +    SCMP_SYS(getpid),
 +#ifdef __NR_getrlimit
 +    SCMP_SYS(getrlimit),
 +#endif
 +    SCMP_SYS(gettimeofday),
 +    SCMP_SYS(gettid),
 +    SCMP_SYS(getuid),
 +#ifdef __NR_getuid32
 +    SCMP_SYS(getuid32),
 +#endif
 +    SCMP_SYS(lseek),
 +#ifdef __NR__llseek
 +    SCMP_SYS(_llseek),
 +#endif
 +    SCMP_SYS(mkdir),
 +    SCMP_SYS(mlockall),
 +#ifdef __NR_mmap
 +    /* XXXX restrict this in the same ways as mmap2 */
 +    SCMP_SYS(mmap),
 +#endif
 +    SCMP_SYS(munmap),
 +#ifdef __NR_nanosleep
 +    SCMP_SYS(nanosleep),
 +#endif
 +#ifdef __NR_prlimit
 +    SCMP_SYS(prlimit),
 +#endif
 +#ifdef __NR_prlimit64
 +    SCMP_SYS(prlimit64),
 +#endif
 +    SCMP_SYS(read),
 +    SCMP_SYS(rt_sigreturn),
 +    SCMP_SYS(sched_getaffinity),
 +#ifdef __NR_sched_yield
 +    SCMP_SYS(sched_yield),
 +#endif
 +    SCMP_SYS(sendmsg),
 +    SCMP_SYS(set_robust_list),
 +#ifdef __NR_setrlimit
 +    SCMP_SYS(setrlimit),
 +#endif
++    SCMP_SYS(shutdown),
 +#ifdef __NR_sigaltstack
 +    SCMP_SYS(sigaltstack),
 +#endif
 +#ifdef __NR_sigreturn
 +    SCMP_SYS(sigreturn),
 +#endif
 +    SCMP_SYS(stat),
 +    SCMP_SYS(uname),
 +    SCMP_SYS(wait4),
 +    SCMP_SYS(write),
 +    SCMP_SYS(writev),
 +    SCMP_SYS(exit_group),
 +    SCMP_SYS(exit),
 +
 +    SCMP_SYS(madvise),
 +#ifdef __NR_stat64
 +    // getaddrinfo uses this..
 +    SCMP_SYS(stat64),
 +#endif
 +
 +#ifdef __NR_getrandom
 +    SCMP_SYS(getrandom),
 +#endif
 +
 +#ifdef __NR_sysinfo
 +    // qsort uses this..
 +    SCMP_SYS(sysinfo),
 +#endif
 +    /*
 +     * These socket syscalls are not required on x86_64 and not supported with
 +     * some libseccomp versions (eg: 1.0.1)
 +     */
 +#if defined(__i386)
 +    SCMP_SYS(recv),
 +    SCMP_SYS(send),
 +#endif
 +
 +    // socket syscalls
 +    SCMP_SYS(bind),
 +    SCMP_SYS(listen),
 +    SCMP_SYS(connect),
 +    SCMP_SYS(getsockname),
 +    SCMP_SYS(recvmsg),
 +    SCMP_SYS(recvfrom),
 +    SCMP_SYS(sendto),
 +    SCMP_SYS(unlink),
 +    SCMP_SYS(poll)
 +};
 +
 +/* These macros help avoid the error where the number of filters we add on a
 + * single rule don't match the arg_cnt param. */
 +#define seccomp_rule_add_0(ctx,act,call) \
 +  seccomp_rule_add((ctx),(act),(call),0)
 +#define seccomp_rule_add_1(ctx,act,call,f1) \
 +  seccomp_rule_add((ctx),(act),(call),1,(f1))
 +#define seccomp_rule_add_2(ctx,act,call,f1,f2)  \
 +  seccomp_rule_add((ctx),(act),(call),2,(f1),(f2))
 +#define seccomp_rule_add_3(ctx,act,call,f1,f2,f3)       \
 +  seccomp_rule_add((ctx),(act),(call),3,(f1),(f2),(f3))
 +#define seccomp_rule_add_4(ctx,act,call,f1,f2,f3,f4)      \
 +  seccomp_rule_add((ctx),(act),(call),4,(f1),(f2),(f3),(f4))
 +
 +/**
 + * Function responsible for setting up the rt_sigaction syscall for
 + * the seccomp filter sandbox.
 + */
 +static int
 +sb_rt_sigaction(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  unsigned i;
 +  int rc;
 +  int param[] = { SIGINT, SIGTERM, SIGPIPE, SIGUSR1, SIGUSR2, SIGHUP, SIGCHLD,
 +#ifdef SIGXFSZ
 +      SIGXFSZ
 +#endif
 +      };
 +  (void) filter;
 +
 +  for (i = 0; i < ARRAY_LENGTH(param); i++) {
 +    rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(rt_sigaction),
 +        SCMP_CMP(0, SCMP_CMP_EQ, param[i]));
 +    if (rc)
 +      break;
 +  }
 +
 +  return rc;
 +}
 +
 +/**
 + * Function responsible for setting up the time syscall for
 + * the seccomp filter sandbox.
 + */
 +static int
 +sb_time(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  (void) filter;
 +#ifdef __NR_time
 +  return seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(time),
 +       SCMP_CMP(0, SCMP_CMP_EQ, 0));
 +#else
 +  return 0;
 +#endif /* defined(__NR_time) */
 +}
 +
 +/**
 + * Function responsible for setting up the accept4 syscall for
 + * the seccomp filter sandbox.
 + */
 +static int
 +sb_accept4(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc = 0;
 +  (void)filter;
 +
 +#ifdef __i386__
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socketcall),
 +      SCMP_CMP(0, SCMP_CMP_EQ, 18));
 +  if (rc) {
 +    return rc;
 +  }
 +#endif /* defined(__i386__) */
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(accept4),
 +                   SCMP_CMP_MASKED(3, SOCK_CLOEXEC|SOCK_NONBLOCK, 0));
 +  if (rc) {
 +    return rc;
 +  }
 +
 +  return 0;
 +}
 +
 +#ifdef __NR_mmap2
 +/**
 + * Function responsible for setting up the mmap2 syscall for
 + * the seccomp filter sandbox.
 + */
 +static int
 +sb_mmap2(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc = 0;
 +  (void)filter;
 +
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mmap2),
 +       SCMP_CMP(2, SCMP_CMP_EQ, PROT_READ),
 +       SCMP_CMP(3, SCMP_CMP_EQ, MAP_PRIVATE));
 +  if (rc) {
 +    return rc;
 +  }
 +
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mmap2),
 +       SCMP_CMP(2, SCMP_CMP_EQ, PROT_NONE),
 +       SCMP_CMP(3, SCMP_CMP_EQ, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE));
 +  if (rc) {
 +    return rc;
 +  }
 +
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mmap2),
 +       SCMP_CMP(2, SCMP_CMP_EQ, PROT_READ|PROT_WRITE),
 +       SCMP_CMP(3, SCMP_CMP_EQ, MAP_PRIVATE|MAP_ANONYMOUS));
 +  if (rc) {
 +    return rc;
 +  }
 +
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mmap2),
 +       SCMP_CMP(2, SCMP_CMP_EQ, PROT_READ|PROT_WRITE),
 +       SCMP_CMP(3, SCMP_CMP_EQ,MAP_PRIVATE|MAP_ANONYMOUS|MAP_STACK));
 +  if (rc) {
 +    return rc;
 +  }
 +
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mmap2),
 +      SCMP_CMP(2, SCMP_CMP_EQ, PROT_READ|PROT_WRITE),
 +      SCMP_CMP(3, SCMP_CMP_EQ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE));
 +  if (rc) {
 +    return rc;
 +  }
 +
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mmap2),
 +      SCMP_CMP(2, SCMP_CMP_EQ, PROT_READ|PROT_WRITE),
 +      SCMP_CMP(3, SCMP_CMP_EQ, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS));
 +  if (rc) {
 +    return rc;
 +  }
 +
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mmap2),
 +      SCMP_CMP(2, SCMP_CMP_EQ, PROT_READ|PROT_EXEC),
 +      SCMP_CMP(3, SCMP_CMP_EQ, MAP_PRIVATE|MAP_DENYWRITE));
 +  if (rc) {
 +    return rc;
 +  }
 +
 +  return 0;
 +}
 +#endif /* defined(__NR_mmap2) */
 +
 +#ifdef HAVE_GNU_LIBC_VERSION_H
 +#ifdef HAVE_GNU_GET_LIBC_VERSION
 +#define CHECK_LIBC_VERSION
 +#endif
 +#endif
 +
 +/* Return true if we think we're running with a libc that always uses
 + * openat on linux. */
 +static int
 +libc_uses_openat_for_everything(void)
 +{
 +#ifdef CHECK_LIBC_VERSION
 +  const char *version = gnu_get_libc_version();
 +  if (version == NULL)
 +    return 0;
 +
 +  int major = -1;
 +  int minor = -1;
 +
 +  tor_sscanf(version, "%d.%d", &major, &minor);
 +  if (major >= 3)
 +    return 1;
 +  else if (major == 2 && minor >= 26)
 +    return 1;
 +  else
 +    return 0;
 +#else /* !(defined(CHECK_LIBC_VERSION)) */
 +  return 0;
 +#endif /* defined(CHECK_LIBC_VERSION) */
 +}
 +
 +/** Allow a single file to be opened.  If <b>use_openat</b> is true,
 + * we're using a libc that remaps all the opens into openats. */
 +static int
 +allow_file_open(scmp_filter_ctx ctx, int use_openat, const char *file)
 +{
 +  if (use_openat) {
 +    return seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(openat),
 +                              SCMP_CMP(0, SCMP_CMP_EQ, (unsigned int)AT_FDCWD),
 +                              SCMP_CMP_STR(1, SCMP_CMP_EQ, file));
 +  } else {
 +    return seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(open),
 +                              SCMP_CMP_STR(0, SCMP_CMP_EQ, file));
 +  }
 +}
 +
 +/**
 + * Function responsible for setting up the open syscall for
 + * the seccomp filter sandbox.
 + */
 +static int
 +sb_open(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc;
 +  sandbox_cfg_t *elem = NULL;
 +
 +  int use_openat = libc_uses_openat_for_everything();
 +
 +  // for each dynamic parameter filters
 +  for (elem = filter; elem != NULL; elem = elem->next) {
 +    smp_param_t *param = elem->param;
 +
 +    if (param != NULL && param->prot == 1 && param->syscall
 +        == SCMP_SYS(open)) {
 +      rc = allow_file_open(ctx, use_openat, param->value);
 +      if (rc != 0) {
 +        log_err(LD_BUG,"(Sandbox) failed to add open syscall, received "
 +            "libseccomp error %d", rc);
 +        return rc;
 +      }
 +    }
 +  }
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ERRNO(EACCES), SCMP_SYS(open),
 +                SCMP_CMP_MASKED(1, O_CLOEXEC|O_NONBLOCK|O_NOCTTY|O_NOFOLLOW,
 +                                O_RDONLY));
 +  if (rc != 0) {
 +    log_err(LD_BUG,"(Sandbox) failed to add open syscall, received libseccomp "
 +        "error %d", rc);
 +    return rc;
 +  }
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ERRNO(EACCES), SCMP_SYS(openat),
 +                SCMP_CMP_MASKED(2, O_CLOEXEC|O_NONBLOCK|O_NOCTTY|O_NOFOLLOW,
 +                                O_RDONLY));
 +  if (rc != 0) {
 +    log_err(LD_BUG,"(Sandbox) failed to add openat syscall, received "
 +            "libseccomp error %d", rc);
 +    return rc;
 +  }
 +
 +  return 0;
 +}
 +
 +static int
 +sb_chmod(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc;
 +  sandbox_cfg_t *elem = NULL;
 +
 +  // for each dynamic parameter filters
 +  for (elem = filter; elem != NULL; elem = elem->next) {
 +    smp_param_t *param = elem->param;
 +
 +    if (param != NULL && param->prot == 1 && param->syscall
 +        == SCMP_SYS(chmod)) {
 +      rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(chmod),
 +            SCMP_CMP_STR(0, SCMP_CMP_EQ, param->value));
 +      if (rc != 0) {
 +        log_err(LD_BUG,"(Sandbox) failed to add chmod syscall, received "
 +            "libseccomp error %d", rc);
 +        return rc;
 +      }
 +    }
 +  }
 +
 +  return 0;
 +}
 +
 +static int
 +sb_chown(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc;
 +  sandbox_cfg_t *elem = NULL;
 +
 +  // for each dynamic parameter filters
 +  for (elem = filter; elem != NULL; elem = elem->next) {
 +    smp_param_t *param = elem->param;
 +
 +    if (param != NULL && param->prot == 1 && param->syscall
 +        == SCMP_SYS(chown)) {
 +      rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(chown),
 +            SCMP_CMP_STR(0, SCMP_CMP_EQ, param->value));
 +      if (rc != 0) {
 +        log_err(LD_BUG,"(Sandbox) failed to add chown syscall, received "
 +            "libseccomp error %d", rc);
 +        return rc;
 +      }
 +    }
 +  }
 +
 +  return 0;
 +}
 +
 +static int
 +sb__sysctl(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc;
 +  (void) filter;
 +  (void) ctx;
 +
 +  rc = seccomp_rule_add_0(ctx, SCMP_ACT_ERRNO(EPERM), SCMP_SYS(_sysctl));
 +  if (rc != 0) {
 +    log_err(LD_BUG,"(Sandbox) failed to add _sysctl syscall, "
 +        "received libseccomp error %d", rc);
 +    return rc;
 +  }
 +
 +  return 0;
 +}
 +
 +/**
 + * Function responsible for setting up the rename syscall for
 + * the seccomp filter sandbox.
 + */
 +static int
 +sb_rename(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc;
 +  sandbox_cfg_t *elem = NULL;
 +
 +  // for each dynamic parameter filters
 +  for (elem = filter; elem != NULL; elem = elem->next) {
 +    smp_param_t *param = elem->param;
 +
 +    if (param != NULL && param->prot == 1 &&
 +        param->syscall == SCMP_SYS(rename)) {
 +
 +      rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(rename),
 +            SCMP_CMP_STR(0, SCMP_CMP_EQ, param->value),
 +            SCMP_CMP_STR(1, SCMP_CMP_EQ, param->value2));
 +      if (rc != 0) {
 +        log_err(LD_BUG,"(Sandbox) failed to add rename syscall, received "
 +            "libseccomp error %d", rc);
 +        return rc;
 +      }
 +    }
 +  }
 +
 +  return 0;
 +}
 +
 +/**
 + * Function responsible for setting up the openat syscall for
 + * the seccomp filter sandbox.
 + */
 +static int
 +sb_openat(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc;
 +  sandbox_cfg_t *elem = NULL;
 +
 +  // for each dynamic parameter filters
 +  for (elem = filter; elem != NULL; elem = elem->next) {
 +    smp_param_t *param = elem->param;
 +
 +    if (param != NULL && param->prot == 1 && param->syscall
 +        == SCMP_SYS(openat)) {
 +      rc = seccomp_rule_add_3(ctx, SCMP_ACT_ALLOW, SCMP_SYS(openat),
 +          SCMP_CMP(0, SCMP_CMP_EQ, AT_FDCWD),
 +          SCMP_CMP_STR(1, SCMP_CMP_EQ, param->value),
 +          SCMP_CMP(2, SCMP_CMP_EQ, O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_DIRECTORY|
 +              O_CLOEXEC));
 +      if (rc != 0) {
 +        log_err(LD_BUG,"(Sandbox) failed to add openat syscall, received "
 +            "libseccomp error %d", rc);
 +        return rc;
 +      }
 +    }
 +  }
 +
 +  return 0;
 +}
 +
 +/**
 + * Function responsible for setting up the socket syscall for
 + * the seccomp filter sandbox.
 + */
 +static int
 +sb_socket(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc = 0;
 +  int i, j;
 +  (void) filter;
 +
 +#ifdef __i386__
 +  rc = seccomp_rule_add_0(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket));
 +  if (rc)
 +    return rc;
 +#endif
 +
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket),
 +      SCMP_CMP(0, SCMP_CMP_EQ, PF_FILE),
 +      SCMP_CMP_MASKED(1, SOCK_CLOEXEC|SOCK_NONBLOCK, SOCK_STREAM));
 +  if (rc)
 +    return rc;
 +
 +  for (i = 0; i < 2; ++i) {
 +    const int pf = i ? PF_INET : PF_INET6;
 +    for (j=0; j < 3; ++j) {
 +      const int type     = (j == 0) ? SOCK_STREAM :
 +                                      SOCK_DGRAM;
 +      const int protocol = (j == 0) ? IPPROTO_TCP :
 +                           (j == 1) ? IPPROTO_IP :
 +                                      IPPROTO_UDP;
 +      rc = seccomp_rule_add_3(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket),
 +        SCMP_CMP(0, SCMP_CMP_EQ, pf),
 +        SCMP_CMP_MASKED(1, SOCK_CLOEXEC|SOCK_NONBLOCK, type),
 +        SCMP_CMP(2, SCMP_CMP_EQ, protocol));
 +      if (rc)
 +        return rc;
 +    }
 +  }
 +
 +  rc = seccomp_rule_add_3(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket),
 +      SCMP_CMP(0, SCMP_CMP_EQ, PF_UNIX),
 +      SCMP_CMP_MASKED(1, SOCK_CLOEXEC|SOCK_NONBLOCK, SOCK_STREAM),
 +      SCMP_CMP(2, SCMP_CMP_EQ, 0));
 +  if (rc)
 +    return rc;
 +
 +  rc = seccomp_rule_add_3(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket),
 +      SCMP_CMP(0, SCMP_CMP_EQ, PF_UNIX),
 +      SCMP_CMP_MASKED(1, SOCK_CLOEXEC|SOCK_NONBLOCK, SOCK_DGRAM),
 +      SCMP_CMP(2, SCMP_CMP_EQ, 0));
 +  if (rc)
 +    return rc;
 +
 +  rc = seccomp_rule_add_3(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket),
 +      SCMP_CMP(0, SCMP_CMP_EQ, PF_NETLINK),
 +      SCMP_CMP_MASKED(1, SOCK_CLOEXEC, SOCK_RAW),
 +      SCMP_CMP(2, SCMP_CMP_EQ, 0));
 +  if (rc)
 +    return rc;
 +
 +  return 0;
 +}
 +
 +/**
 + * Function responsible for setting up the socketpair syscall for
 + * the seccomp filter sandbox.
 + */
 +static int
 +sb_socketpair(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc = 0;
 +  (void) filter;
 +
 +#ifdef __i386__
 +  rc = seccomp_rule_add_0(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socketpair));
 +  if (rc)
 +    return rc;
 +#endif
 +
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socketpair),
 +      SCMP_CMP(0, SCMP_CMP_EQ, PF_FILE),
 +      SCMP_CMP(1, SCMP_CMP_EQ, SOCK_STREAM|SOCK_CLOEXEC));
 +  if (rc)
 +    return rc;
 +
 +  return 0;
 +}
 +
 +#ifdef HAVE_KIST_SUPPORT
 +
 +#include <linux/sockios.h>
 +
 +static int
 +sb_ioctl(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc;
 +  (void) filter;
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(ioctl),
 +                          SCMP_CMP(1, SCMP_CMP_EQ, SIOCOUTQNSD));
 +  if (rc)
 +    return rc;
 +  return 0;
 +}
 +
 +#endif /* defined(HAVE_KIST_SUPPORT) */
 +
 +/**
 + * Function responsible for setting up the setsockopt syscall for
 + * the seccomp filter sandbox.
 + */
 +static int
 +sb_setsockopt(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc = 0;
 +  (void) filter;
 +
 +#ifdef __i386__
 +  rc = seccomp_rule_add_0(ctx, SCMP_ACT_ALLOW, SCMP_SYS(setsockopt));
 +  if (rc)
 +    return rc;
 +#endif
 +
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(setsockopt),
 +      SCMP_CMP(1, SCMP_CMP_EQ, SOL_SOCKET),
 +      SCMP_CMP(2, SCMP_CMP_EQ, SO_REUSEADDR));
 +  if (rc)
 +    return rc;
 +
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(setsockopt),
 +      SCMP_CMP(1, SCMP_CMP_EQ, SOL_SOCKET),
 +      SCMP_CMP(2, SCMP_CMP_EQ, SO_SNDBUF));
 +  if (rc)
 +    return rc;
 +
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(setsockopt),
 +      SCMP_CMP(1, SCMP_CMP_EQ, SOL_SOCKET),
 +      SCMP_CMP(2, SCMP_CMP_EQ, SO_RCVBUF));
 +  if (rc)
 +    return rc;
 +
 +#ifdef HAVE_SYSTEMD
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(setsockopt),
 +      SCMP_CMP(1, SCMP_CMP_EQ, SOL_SOCKET),
 +      SCMP_CMP(2, SCMP_CMP_EQ, SO_SNDBUFFORCE));
 +  if (rc)
 +    return rc;
 +#endif /* defined(HAVE_SYSTEMD) */
 +
 +#ifdef IP_TRANSPARENT
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(setsockopt),
 +      SCMP_CMP(1, SCMP_CMP_EQ, SOL_IP),
 +      SCMP_CMP(2, SCMP_CMP_EQ, IP_TRANSPARENT));
 +  if (rc)
 +    return rc;
 +#endif /* defined(IP_TRANSPARENT) */
 +
 +#ifdef IPV6_V6ONLY
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(setsockopt),
 +      SCMP_CMP(1, SCMP_CMP_EQ, IPPROTO_IPV6),
 +      SCMP_CMP(2, SCMP_CMP_EQ, IPV6_V6ONLY));
 +  if (rc)
 +    return rc;
 +#endif /* defined(IPV6_V6ONLY) */
 +
 +  return 0;
 +}
 +
 +/**
 + * Function responsible for setting up the getsockopt syscall for
 + * the seccomp filter sandbox.
 + */
 +static int
 +sb_getsockopt(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc = 0;
 +  (void) filter;
 +
 +#ifdef __i386__
 +  rc = seccomp_rule_add_0(ctx, SCMP_ACT_ALLOW, SCMP_SYS(getsockopt));
 +  if (rc)
 +    return rc;
 +#endif
 +
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(getsockopt),
 +      SCMP_CMP(1, SCMP_CMP_EQ, SOL_SOCKET),
 +      SCMP_CMP(2, SCMP_CMP_EQ, SO_ERROR));
 +  if (rc)
 +    return rc;
 +
 +#ifdef HAVE_SYSTEMD
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(getsockopt),
 +      SCMP_CMP(1, SCMP_CMP_EQ, SOL_SOCKET),
 +      SCMP_CMP(2, SCMP_CMP_EQ, SO_SNDBUF));
 +  if (rc)
 +    return rc;
 +#endif /* defined(HAVE_SYSTEMD) */
 +
 +#ifdef HAVE_LINUX_NETFILTER_IPV4_H
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(getsockopt),
 +      SCMP_CMP(1, SCMP_CMP_EQ, SOL_IP),
 +      SCMP_CMP(2, SCMP_CMP_EQ, SO_ORIGINAL_DST));
 +  if (rc)
 +    return rc;
 +#endif /* defined(HAVE_LINUX_NETFILTER_IPV4_H) */
 +
 +#ifdef HAVE_LINUX_NETFILTER_IPV6_IP6_TABLES_H
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(getsockopt),
 +      SCMP_CMP(1, SCMP_CMP_EQ, SOL_IPV6),
 +      SCMP_CMP(2, SCMP_CMP_EQ, IP6T_SO_ORIGINAL_DST));
 +  if (rc)
 +    return rc;
 +#endif /* defined(HAVE_LINUX_NETFILTER_IPV6_IP6_TABLES_H) */
 +
 +#ifdef HAVE_KIST_SUPPORT
 +#include <netinet/tcp.h>
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(getsockopt),
 +      SCMP_CMP(1, SCMP_CMP_EQ, SOL_TCP),
 +      SCMP_CMP(2, SCMP_CMP_EQ, TCP_INFO));
 +  if (rc)
 +    return rc;
 +#endif /* defined(HAVE_KIST_SUPPORT) */
 +
 +  return 0;
 +}
 +
 +#ifdef __NR_fcntl64
 +/**
 + * Function responsible for setting up the fcntl64 syscall for
 + * the seccomp filter sandbox.
 + */
 +static int
 +sb_fcntl64(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc = 0;
 +  (void) filter;
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl64),
 +      SCMP_CMP(1, SCMP_CMP_EQ, F_GETFL));
 +  if (rc)
 +    return rc;
 +
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl64),
 +      SCMP_CMP(1, SCMP_CMP_EQ, F_SETFL),
 +      SCMP_CMP(2, SCMP_CMP_EQ, O_RDWR|O_NONBLOCK));
 +  if (rc)
 +    return rc;
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl64),
 +      SCMP_CMP(1, SCMP_CMP_EQ, F_GETFD));
 +  if (rc)
 +    return rc;
 +
 +  rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl64),
 +      SCMP_CMP(1, SCMP_CMP_EQ, F_SETFD),
 +      SCMP_CMP(2, SCMP_CMP_EQ, FD_CLOEXEC));
 +  if (rc)
 +    return rc;
 +
 +  return 0;
 +}
 +#endif /* defined(__NR_fcntl64) */
 +
 +/**
 + * Function responsible for setting up the epoll_ctl syscall for
 + * the seccomp filter sandbox.
 + *
 + *  Note: basically allows everything but will keep for now..
 + */
 +static int
 +sb_epoll_ctl(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc = 0;
 +  (void) filter;
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(epoll_ctl),
 +      SCMP_CMP(1, SCMP_CMP_EQ, EPOLL_CTL_ADD));
 +  if (rc)
 +    return rc;
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(epoll_ctl),
 +      SCMP_CMP(1, SCMP_CMP_EQ, EPOLL_CTL_MOD));
 +  if (rc)
 +    return rc;
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(epoll_ctl),
 +      SCMP_CMP(1, SCMP_CMP_EQ, EPOLL_CTL_DEL));
 +  if (rc)
 +    return rc;
 +
 +  return 0;
 +}
 +
 +/**
 + * Function responsible for setting up the prctl syscall for
 + * the seccomp filter sandbox.
 + *
 + * NOTE: if multiple filters need to be added, the PR_SECCOMP parameter needs
 + * to be whitelisted in this function.
 + */
 +static int
 +sb_prctl(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc = 0;
 +  (void) filter;
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(prctl),
 +      SCMP_CMP(0, SCMP_CMP_EQ, PR_SET_DUMPABLE));
 +  if (rc)
 +    return rc;
 +
 +  return 0;
 +}
 +
 +/**
 + * Function responsible for setting up the mprotect syscall for
 + * the seccomp filter sandbox.
 + *
 + * NOTE: does not NEED to be here.. currently only occurs before filter; will
 + * keep just in case for the future.
 + */
 +static int
 +sb_mprotect(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc = 0;
 +  (void) filter;
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mprotect),
 +      SCMP_CMP(2, SCMP_CMP_EQ, PROT_READ));
 +  if (rc)
 +    return rc;
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mprotect),
 +      SCMP_CMP(2, SCMP_CMP_EQ, PROT_NONE));
 +  if (rc)
 +    return rc;
 +
 +  return 0;
 +}
 +
 +/**
 + * Function responsible for setting up the rt_sigprocmask syscall for
 + * the seccomp filter sandbox.
 + */
 +static int
 +sb_rt_sigprocmask(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc = 0;
 +  (void) filter;
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(rt_sigprocmask),
 +      SCMP_CMP(0, SCMP_CMP_EQ, SIG_UNBLOCK));
 +  if (rc)
 +    return rc;
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(rt_sigprocmask),
 +      SCMP_CMP(0, SCMP_CMP_EQ, SIG_SETMASK));
 +  if (rc)
 +    return rc;
 +
 +  return 0;
 +}
 +
 +/**
 + * Function responsible for setting up the flock syscall for
 + * the seccomp filter sandbox.
 + *
 + *  NOTE: does not need to be here, occurs before filter is applied.
 + */
 +static int
 +sb_flock(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc = 0;
 +  (void) filter;
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(flock),
 +      SCMP_CMP(1, SCMP_CMP_EQ, LOCK_EX|LOCK_NB));
 +  if (rc)
 +    return rc;
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(flock),
 +      SCMP_CMP(1, SCMP_CMP_EQ, LOCK_UN));
 +  if (rc)
 +    return rc;
 +
 +  return 0;
 +}
 +
 +/**
 + * Function responsible for setting up the futex syscall for
 + * the seccomp filter sandbox.
 + */
 +static int
 +sb_futex(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc = 0;
 +  (void) filter;
 +
 +  // can remove
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(futex),
 +      SCMP_CMP(1, SCMP_CMP_EQ,
 +          FUTEX_WAIT_BITSET_PRIVATE|FUTEX_CLOCK_REALTIME));
 +  if (rc)
 +    return rc;
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(futex),
 +      SCMP_CMP(1, SCMP_CMP_EQ, FUTEX_WAKE_PRIVATE));
 +  if (rc)
 +    return rc;
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(futex),
 +      SCMP_CMP(1, SCMP_CMP_EQ, FUTEX_WAIT_PRIVATE));
 +  if (rc)
 +    return rc;
 +
 +  return 0;
 +}
 +
 +/**
 + * Function responsible for setting up the mremap syscall for
 + * the seccomp filter sandbox.
 + *
 + *  NOTE: so far only occurs before filter is applied.
 + */
 +static int
 +sb_mremap(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc = 0;
 +  (void) filter;
 +
 +  rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mremap),
 +      SCMP_CMP(3, SCMP_CMP_EQ, MREMAP_MAYMOVE));
 +  if (rc)
 +    return rc;
 +
 +  return 0;
 +}
 +
 +#ifdef __NR_stat64
 +/**
 + * Function responsible for setting up the stat64 syscall for
 + * the seccomp filter sandbox.
 + */
 +static int
 +sb_stat64(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  int rc = 0;
 +  sandbox_cfg_t *elem = NULL;
 +
 +  // for each dynamic parameter filters
 +  for (elem = filter; elem != NULL; elem = elem->next) {
 +    smp_param_t *param = elem->param;
 +
 +    if (param != NULL && param->prot == 1 && (param->syscall == SCMP_SYS(open)
 +        || param->syscall == SCMP_SYS(stat64))) {
 +      rc = seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(stat64),
 +          SCMP_CMP_STR(0, SCMP_CMP_EQ, param->value));
 +      if (rc != 0) {
 +        log_err(LD_BUG,"(Sandbox) failed to add stat64 syscall, received "
 +            "libseccomp error %d", rc);
 +        return rc;
 +      }
 +    }
 +  }
 +
 +  return 0;
 +}
 +#endif /* defined(__NR_stat64) */
 +
 +static int
 +sb_kill(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
 +{
 +  (void) filter;
 +#ifdef __NR_kill
 +  /* Allow killing anything with signal 0 -- it isn't really a kill. */
 +  return seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(kill),
 +       SCMP_CMP(1, SCMP_CMP_EQ, 0));
 +#else
 +  return 0;
 +#endif /* defined(__NR_kill) */
 +}
 +
 +/**
 + * Array of function pointers responsible for filtering different syscalls at
 + * a parameter level.
 + */
 +static sandbox_filter_func_t filter_func[] = {
 +    sb_rt_sigaction,
 +    sb_rt_sigprocmask,
 +    sb_time,
 +    sb_accept4,
 +#ifdef __NR_mmap2
 +    sb_mmap2,
 +#endif
 +    sb_chown,
 +    sb_chmod,
 +    sb_open,
 +    sb_openat,
 +    sb__sysctl,
 +    sb_rename,
 +#ifdef __NR_fcntl64
 +    sb_fcntl64,
 +#endif
 +    sb_epoll_ctl,
 +    sb_prctl,
 +    sb_mprotect,
 +    sb_flock,
 +    sb_futex,
 +    sb_mremap,
 +#ifdef __NR_stat64
 +    sb_stat64,
 +#endif
 +
 +    sb_socket,
 +    sb_setsockopt,
 +    sb_getsockopt,
 +    sb_socketpair,
 +#ifdef HAVE_KIST_SUPPORT
 +    sb_ioctl,
 +#endif
 +    sb_kill
 +};
 +
 +const char *
 +sandbox_intern_string(const char *str)
 +{
 +  sandbox_cfg_t *elem;
 +
 +  if (str == NULL)
 +    return NULL;
 +
 +  for (elem = filter_dynamic; elem != NULL; elem = elem->next) {
 +    smp_param_t *param = elem->param;
 +
 +    if (param->prot) {
 +      if (!strcmp(str, (char*)(param->value))) {
 +        return (char*)param->value;
 +      }
 +      if (param->value2 && !strcmp(str, (char*)param->value2)) {
 +        return (char*)param->value2;
 +      }
 +    }
 +  }
 +
 +  if (sandbox_active)
 +    log_warn(LD_BUG, "No interned sandbox parameter found for %s", str);
 +  return str;
 +}
 +
 +/* DOCDOC */
 +static int
 +prot_strings_helper(strmap_t *locations,
 +                    char **pr_mem_next_p,
 +                    size_t *pr_mem_left_p,
 +                    char **value_p)
 +{
 +  char *param_val;
 +  size_t param_size;
 +  void *location;
 +
 +  if (*value_p == 0)
 +    return 0;
 +
 +  param_val = (char*) *value_p;
 +  param_size = strlen(param_val) + 1;
 +  location = strmap_get(locations, param_val);
 +
 +  if (location) {
 +    // We already interned this string.
 +    tor_free(param_val);
 +    *value_p = location;
 +    return 0;
 +  } else if (*pr_mem_left_p >= param_size) {
 +    // copy to protected
 +    location = *pr_mem_next_p;
 +    memcpy(location, param_val, param_size);
 +
 +    // re-point el parameter to protected
 +    tor_free(param_val);
 +    *value_p = location;
 +
 +    strmap_set(locations, location, location); /* good real estate advice */
 +
 +    // move next available protected memory
 +    *pr_mem_next_p += param_size;
 +    *pr_mem_left_p -= param_size;
 +    return 0;
 +  } else {
 +    log_err(LD_BUG,"(Sandbox) insufficient protected memory!");
 +    return -1;
 +  }
 +}
 +
 +/**
 + * Protects all the strings in the sandbox's parameter list configuration. It
 + * works by calculating the total amount of memory required by the parameter
 + * list, allocating the memory using mmap, and protecting it from writes with
 + * mprotect().
 + */
 +static int
 +prot_strings(scmp_filter_ctx ctx, sandbox_cfg_t* cfg)
 +{
 +  int ret = 0;
 +  size_t pr_mem_size = 0, pr_mem_left = 0;
 +  char *pr_mem_next = NULL, *pr_mem_base;
 +  sandbox_cfg_t *el = NULL;
 +  strmap_t *locations = NULL;
 +
 +  // get total number of bytes required to mmap. (Overestimate.)
 +  for (el = cfg; el != NULL; el = el->next) {
 +    pr_mem_size += strlen((char*) el->param->value) + 1;
 +    if (el->param->value2)
 +      pr_mem_size += strlen((char*) el->param->value2) + 1;
 +  }
 +
 +  // allocate protected memory with MALLOC_MP_LIM canary
 +  pr_mem_base = (char*) mmap(NULL, MALLOC_MP_LIM + pr_mem_size,
 +      PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
 +  if (pr_mem_base == MAP_FAILED) {
 +    log_err(LD_BUG,"(Sandbox) failed allocate protected memory! mmap: %s",
 +        strerror(errno));
 +    ret = -1;
 +    goto out;
 +  }
 +
 +  pr_mem_next = pr_mem_base + MALLOC_MP_LIM;
 +  pr_mem_left = pr_mem_size;
 +
 +  locations = strmap_new();
 +
 +  // change el value pointer to protected
 +  for (el = cfg; el != NULL; el = el->next) {
 +    if (prot_strings_helper(locations, &pr_mem_next, &pr_mem_left,
 +                            &el->param->value) < 0) {
 +      ret = -2;
 +      goto out;
 +    }
 +    if (prot_strings_helper(locations, &pr_mem_next, &pr_mem_left,
 +                            &el->param->value2) < 0) {
 +      ret = -2;
 +      goto out;
 +    }
 +    el->param->prot = 1;
 +  }
 +
 +  // protecting from writes
 +  if (mprotect(pr_mem_base, MALLOC_MP_LIM + pr_mem_size, PROT_READ)) {
 +    log_err(LD_BUG,"(Sandbox) failed to protect memory! mprotect: %s",
 +        strerror(errno));
 +    ret = -3;
 +    goto out;
 +  }
 +
 +  /*
 +   * Setting sandbox restrictions so the string memory cannot be tampered with
 +   */
 +  // no mremap of the protected base address
 +  ret = seccomp_rule_add_1(ctx, SCMP_ACT_KILL, SCMP_SYS(mremap),
 +      SCMP_CMP(0, SCMP_CMP_EQ, (intptr_t) pr_mem_base));
 +  if (ret) {
 +    log_err(LD_BUG,"(Sandbox) mremap protected memory filter fail!");
 +    goto out;
 +  }
 +
 +  // no munmap of the protected base address
 +  ret = seccomp_rule_add_1(ctx, SCMP_ACT_KILL, SCMP_SYS(munmap),
 +        SCMP_CMP(0, SCMP_CMP_EQ, (intptr_t) pr_mem_base));
 +  if (ret) {
 +    log_err(LD_BUG,"(Sandbox) munmap protected memory filter fail!");
 +    goto out;
 +  }
 +
 +  /*
 +   * Allow mprotect with PROT_READ|PROT_WRITE because openssl uses it, but
 +   * never over the memory region used by the protected strings.
 +   *
 +   * PROT_READ|PROT_WRITE was originally fully allowed in sb_mprotect(), but
 +   * had to be removed due to limitation of libseccomp regarding intervals.
 +   *
 +   * There is a restriction on how much you can mprotect with R|W up to the
 +   * size of the canary.
 +   */
 +  ret = seccomp_rule_add_3(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mprotect),
 +      SCMP_CMP(0, SCMP_CMP_LT, (intptr_t) pr_mem_base),
 +      SCMP_CMP(1, SCMP_CMP_LE, MALLOC_MP_LIM),
 +      SCMP_CMP(2, SCMP_CMP_EQ, PROT_READ|PROT_WRITE));
 +  if (ret) {
 +    log_err(LD_BUG,"(Sandbox) mprotect protected memory filter fail (LT)!");
 +    goto out;
 +  }
 +
 +  ret = seccomp_rule_add_3(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mprotect),
 +      SCMP_CMP(0, SCMP_CMP_GT, (intptr_t) pr_mem_base + pr_mem_size +
 +          MALLOC_MP_LIM),
 +      SCMP_CMP(1, SCMP_CMP_LE, MALLOC_MP_LIM),
 +      SCMP_CMP(2, SCMP_CMP_EQ, PROT_READ|PROT_WRITE));
 +  if (ret) {
 +    log_err(LD_BUG,"(Sandbox) mprotect protected memory filter fail (GT)!");
 +    goto out;
 +  }
 +
 + out:
 +  strmap_free(locations, NULL);
 +  return ret;
 +}
 +
 +/**
 + * Auxiliary function used in order to allocate a sandbox_cfg_t element and set
 + * its values according the parameter list. All elements are initialised
 + * with the 'prot' field set to false, as the pointer is not protected at this
 + * point.
 + */
 +static sandbox_cfg_t*
 +new_element2(int syscall, char *value, char *value2)
 +{
 +  smp_param_t *param = NULL;
 +
 +  sandbox_cfg_t *elem = tor_malloc_zero(sizeof(sandbox_cfg_t));
 +  param = elem->param = tor_malloc_zero(sizeof(smp_param_t));
 +
 +  param->syscall = syscall;
 +  param->value = value;
 +  param->value2 = value2;
 +  param->prot = 0;
 +
 +  return elem;
 +}
 +
 +static sandbox_cfg_t*
 +new_element(int syscall, char *value)
 +{
 +  return new_element2(syscall, value, NULL);
 +}
 +
 +#ifdef __NR_stat64
 +#define SCMP_stat SCMP_SYS(stat64)
 +#else
 +#define SCMP_stat SCMP_SYS(stat)
 +#endif
 +
 +int
 +sandbox_cfg_allow_stat_filename(sandbox_cfg_t **cfg, char *file)
 +{
 +  sandbox_cfg_t *elem = NULL;
 +
 +  elem = new_element(SCMP_stat, file);
 +
 +  elem->next = *cfg;
 +  *cfg = elem;
 +
 +  return 0;
 +}
 +
 +int
 +sandbox_cfg_allow_open_filename(sandbox_cfg_t **cfg, char *file)
 +{
 +  sandbox_cfg_t *elem = NULL;
 +
 +  elem = new_element(SCMP_SYS(open), file);
 +
 +  elem->next = *cfg;
 +  *cfg = elem;
 +
 +  return 0;
 +}
 +
 +int
 +sandbox_cfg_allow_chmod_filename(sandbox_cfg_t **cfg, char *file)
 +{
 +  sandbox_cfg_t *elem = NULL;
 +
 +  elem = new_element(SCMP_SYS(chmod), file);
 +
 +  elem->next = *cfg;
 +  *cfg = elem;
 +
 +  return 0;
 +}
 +
 +int
 +sandbox_cfg_allow_chown_filename(sandbox_cfg_t **cfg, char *file)
 +{
 +  sandbox_cfg_t *elem = NULL;
 +
 +  elem = new_element(SCMP_SYS(chown), file);
 +
 +  elem->next = *cfg;
 +  *cfg = elem;
 +
 +  return 0;
 +}
 +
 +int
 +sandbox_cfg_allow_rename(sandbox_cfg_t **cfg, char *file1, char *file2)
 +{
 +  sandbox_cfg_t *elem = NULL;
 +
 +  elem = new_element2(SCMP_SYS(rename), file1, file2);
 +
 +  elem->next = *cfg;
 +  *cfg = elem;
 +
 +  return 0;
 +}
 +
 +int
 +sandbox_cfg_allow_openat_filename(sandbox_cfg_t **cfg, char *file)
 +{
 +  sandbox_cfg_t *elem = NULL;
 +
 +  elem = new_element(SCMP_SYS(openat), file);
 +
 +  elem->next = *cfg;
 +  *cfg = elem;
 +
 +  return 0;
 +}
 +
 +/**
 + * Function responsible for going through the parameter syscall filters and
 + * call each function pointer in the list.
 + */
 +static int
 +add_param_filter(scmp_filter_ctx ctx, sandbox_cfg_t* cfg)
 +{
 +  unsigned i;
 +  int rc = 0;
 +
 +  // function pointer
 +  for (i = 0; i < ARRAY_LENGTH(filter_func); i++) {
 +    rc = filter_func[i](ctx, cfg);
 +    if (rc) {
 +      log_err(LD_BUG,"(Sandbox) failed to add syscall %d, received libseccomp "
 +          "error %d", i, rc);
 +      return rc;
 +    }
 +  }
 +
 +  return 0;
 +}
 +
 +/**
 + * Function responsible of loading the libseccomp syscall filters which do not
 + * have parameter filtering.
 + */
 +static int
 +add_noparam_filter(scmp_filter_ctx ctx)
 +{
 +  unsigned i;
 +  int rc = 0;
 +
 +  // add general filters
 +  for (i = 0; i < ARRAY_LENGTH(filter_nopar_gen); i++) {
 +    rc = seccomp_rule_add_0(ctx, SCMP_ACT_ALLOW, filter_nopar_gen[i]);
 +    if (rc != 0) {
 +      log_err(LD_BUG,"(Sandbox) failed to add syscall index %d (NR=%d), "
 +          "received libseccomp error %d", i, filter_nopar_gen[i], rc);
 +      return rc;
 +    }
 +  }
 +
 +  return 0;
 +}
 +
 +/**
 + * Function responsible for setting up and enabling a global syscall filter.
 + * The function is a prototype developed for stage 1 of sandboxing Tor.
 + * Returns 0 on success.
 + */
 +static int
 +install_syscall_filter(sandbox_cfg_t* cfg)
 +{
 +  int rc = 0;
 +  scmp_filter_ctx ctx;
 +
 +  ctx = seccomp_init(SCMP_ACT_TRAP);
 +  if (ctx == NULL) {
 +    log_err(LD_BUG,"(Sandbox) failed to initialise libseccomp context");
 +    rc = -1;
 +    goto end;
 +  }
 +
 +  // protectign sandbox parameter strings
 +  if ((rc = prot_strings(ctx, cfg))) {
 +    goto end;
 +  }
 +
 +  // add parameter filters
 +  if ((rc = add_param_filter(ctx, cfg))) {
 +    log_err(LD_BUG, "(Sandbox) failed to add param filters!");
 +    goto end;
 +  }
 +
 +  // adding filters with no parameters
 +  if ((rc = add_noparam_filter(ctx))) {
 +    log_err(LD_BUG, "(Sandbox) failed to add param filters!");
 +    goto end;
 +  }
 +
 +  // loading the seccomp2 filter
 +  if ((rc = seccomp_load(ctx))) {
 +    log_err(LD_BUG, "(Sandbox) failed to load: %d (%s)! "
 +            "Are you sure that your kernel has seccomp2 support? The "
 +            "sandbox won't work without it.", rc,
 +            strerror(-rc));
 +    goto end;
 +  }
 +
 +  // marking the sandbox as active
 +  sandbox_active = 1;
 +  tor_make_getaddrinfo_cache_active();
 +
 + end:
 +  seccomp_release(ctx);
 +  return (rc < 0 ? -rc : rc);
 +}
 +
 +#include "lib/sandbox/linux_syscalls.inc"
 +
 +static const char *
 +get_syscall_name(int syscall_num)
 +{
 +  int i;
 +  for (i = 0; SYSCALLS_BY_NUMBER[i].syscall_name; ++i) {
 +    if (SYSCALLS_BY_NUMBER[i].syscall_num == syscall_num)
 +      return SYSCALLS_BY_NUMBER[i].syscall_name;
 +  }
 +
 +  {
 +     static char syscall_name_buf[64];
 +     format_dec_number_sigsafe(syscall_num,
 +                               syscall_name_buf, sizeof(syscall_name_buf));
 +     return syscall_name_buf;
 +  }
 +}
 +
 +#ifdef USE_BACKTRACE
 +#define MAX_DEPTH 256
 +static void *syscall_cb_buf[MAX_DEPTH];
 +#endif
 +
 +/**
 + * Function called when a SIGSYS is caught by the application. It notifies the
 + * user that an error has occurred and either terminates or allows the
 + * application to continue execution, based on the DEBUGGING_CLOSE symbol.
 + */
 +static void
 +sigsys_debugging(int nr, siginfo_t *info, void *void_context)
 +{
 +  ucontext_t *ctx = (ucontext_t *) (void_context);
 +  const char *syscall_name;
 +  int syscall;
 +#ifdef USE_BACKTRACE
 +  size_t depth;
 +  int n_fds, i;
 +  const int *fds = NULL;
 +#endif
 +
 +  (void) nr;
 +
 +  if (info->si_code != SYS_SECCOMP)
 +    return;
 +
 +  if (!ctx)
 +    return;
 +
 +  syscall = (int) ctx->uc_mcontext.M_SYSCALL;
 +
 +#ifdef USE_BACKTRACE
 +  depth = backtrace(syscall_cb_buf, MAX_DEPTH);
 +  /* Clean up the top stack frame so we get the real function
 +   * name for the most recently failing function. */
 +  clean_backtrace(syscall_cb_buf, depth, ctx);
 +#endif /* defined(USE_BACKTRACE) */
 +
 +  syscall_name = get_syscall_name(syscall);
 +
 +  tor_log_err_sigsafe("(Sandbox) Caught a bad syscall attempt (syscall ",
 +                      syscall_name,
 +                      ")\n",
 +                      NULL);
 +
 +#ifdef USE_BACKTRACE
 +  n_fds = tor_log_get_sigsafe_err_fds(&fds);
 +  for (i=0; i < n_fds; ++i)
 +    backtrace_symbols_fd(syscall_cb_buf, (int)depth, fds[i]);
 +#endif
 +
 +#if defined(DEBUGGING_CLOSE)
 +  _exit(1); // exit ok: programming error has led to sandbox failure.
 +#endif // DEBUGGING_CLOSE
 +}
 +
 +/**
 + * Function that adds a handler for SIGSYS, which is the signal thrown
 + * when the application is issuing a syscall which is not allowed. The
 + * main purpose of this function is to help with debugging by identifying
 + * filtered syscalls.
 + */
 +static int
 +install_sigsys_debugging(void)
 +{
 +  struct sigaction act;
 +  sigset_t mask;
 +
 +  memset(&act, 0, sizeof(act));
 +  sigemptyset(&mask);
 +  sigaddset(&mask, SIGSYS);
 +
 +  act.sa_sigaction = &sigsys_debugging;
 +  act.sa_flags = SA_SIGINFO;
 +  if (sigaction(SIGSYS, &act, NULL) < 0) {
 +    log_err(LD_BUG,"(Sandbox) Failed to register SIGSYS signal handler");
 +    return -1;
 +  }
 +
 +  if (sigprocmask(SIG_UNBLOCK, &mask, NULL)) {
 +    log_err(LD_BUG,"(Sandbox) Failed call to sigprocmask()");
 +    return -2;
 +  }
 +
 +  return 0;
 +}
 +
 +/**
 + * Function responsible of registering the sandbox_cfg_t list of parameter
 + * syscall filters to the existing parameter list. This is used for incipient
 + * multiple-sandbox support.
 + */
 +static int
 +register_cfg(sandbox_cfg_t* cfg)
 +{
 +  sandbox_cfg_t *elem = NULL;
 +
 +  if (filter_dynamic == NULL) {
 +    filter_dynamic = cfg;
 +    return 0;
 +  }
 +
 +  for (elem = filter_dynamic; elem->next != NULL; elem = elem->next)
 +    ;
 +
 +  elem->next = cfg;
 +
 +  return 0;
 +}
 +
 +#endif /* defined(USE_LIBSECCOMP) */
 +
 +#ifdef USE_LIBSECCOMP
 +/**
 + * Initialises the syscall sandbox filter for any linux architecture, taking
 + * into account various available features for different linux flavours.
 + */
 +static int
 +initialise_libseccomp_sandbox(sandbox_cfg_t* cfg)
 +{
 +  /* Prevent glibc from trying to open /dev/tty on fatal error */
 +  setenv("LIBC_FATAL_STDERR_", "1", 1);
 +
 +  if (install_sigsys_debugging())
 +    return -1;
 +
 +  if (install_syscall_filter(cfg))
 +    return -2;
 +
 +  if (register_cfg(cfg))
 +    return -3;
 +
 +  return 0;
 +}
 +
 +int
 +sandbox_is_active(void)
 +{
 +  return sandbox_active != 0;
 +}
 +#endif /* defined(USE_LIBSECCOMP) */
 +
 +sandbox_cfg_t*
 +sandbox_cfg_new(void)
 +{
 +  return NULL;
 +}
 +
 +int
 +sandbox_init(sandbox_cfg_t *cfg)
 +{
 +#if defined(USE_LIBSECCOMP)
 +  return initialise_libseccomp_sandbox(cfg);
 +
 +#elif defined(__linux__)
 +  (void)cfg;
 +  log_warn(LD_GENERAL,
 +           "This version of Tor was built without support for sandboxing. To "
 +           "build with support for sandboxing on Linux, you must have "
 +           "libseccomp and its necessary header files (e.g. seccomp.h).");
 +  return 0;
 +
 +#else
 +  (void)cfg;
 +  log_warn(LD_GENERAL,
 +           "Currently, sandboxing is only implemented on Linux. The feature "
 +           "is disabled on your platform.");
 +  return 0;
 +#endif /* defined(USE_LIBSECCOMP) || ... */
 +}
 +
 +#ifndef USE_LIBSECCOMP
 +int
 +sandbox_cfg_allow_open_filename(sandbox_cfg_t **cfg, char *file)
 +{
 +  (void)cfg; (void)file;
 +  return 0;
 +}
 +
 +int
 +sandbox_cfg_allow_openat_filename(sandbox_cfg_t **cfg, char *file)
 +{
 +  (void)cfg; (void)file;
 +  return 0;
 +}
 +
 +int
 +sandbox_cfg_allow_stat_filename(sandbox_cfg_t **cfg, char *file)
 +{
 +  (void)cfg; (void)file;
 +  return 0;
 +}
 +
 +int
 +sandbox_cfg_allow_chown_filename(sandbox_cfg_t **cfg, char *file)
 +{
 +  (void)cfg; (void)file;
 +  return 0;
 +}
 +
 +int
 +sandbox_cfg_allow_chmod_filename(sandbox_cfg_t **cfg, char *file)
 +{
 +  (void)cfg; (void)file;
 +  return 0;
 +}
 +
 +int
 +sandbox_cfg_allow_rename(sandbox_cfg_t **cfg, char *file1, char *file2)
 +{
 +  (void)cfg; (void)file1; (void)file2;
 +  return 0;
 +}
 +
 +int
 +sandbox_is_active(void)
 +{
 +  return 0;
 +}
 +
 +void
 +sandbox_disable_getaddrinfo_cache(void)
 +{
 +}
++
 +#endif /* !defined(USE_LIBSECCOMP) */

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