diff options
| -rw-r--r-- | configure.ac | 8 | ||||
| -rw-r--r-- | src/common/address.c | 3 | ||||
| -rw-r--r-- | src/common/compat.c | 2 | ||||
| -rw-r--r-- | src/common/crypto.c | 3 | ||||
| -rw-r--r-- | src/common/sandbox.c | 1364 | ||||
| -rw-r--r-- | src/common/sandbox.h | 201 | ||||
| -rw-r--r-- | src/common/util.c | 8 | ||||
| -rw-r--r-- | src/common/util.h | 2 | ||||
| -rw-r--r-- | src/or/config.c | 3 | ||||
| -rw-r--r-- | src/or/dns.c | 15 | ||||
| -rw-r--r-- | src/or/main.c | 99 | ||||
| -rw-r--r-- | src/or/routerlist.c | 2 |
12 files changed, 1616 insertions, 94 deletions
diff --git a/configure.ac b/configure.ac index 2ea69c984..7259d8812 100644 --- a/configure.ac +++ b/configure.ac @@ -402,7 +402,13 @@ save_CPPFLAGS="$CPPFLAGS" LIBS="-levent $STATIC_LIBEVENT_FLAGS $TOR_LIB_WS32 $LIBS" LDFLAGS="$TOR_LDFLAGS_libevent $LDFLAGS" CPPFLAGS="$TOR_CPPFLAGS_libevent $CPPFLAGS" -AC_CHECK_FUNCS(event_get_version event_get_version_number event_get_method event_set_log_callback evdns_set_outgoing_bind_address event_base_loopexit) +AC_CHECK_FUNCS([event_get_version \ + event_get_version_number \ + event_get_method \ + event_set_log_callback \ + evdns_set_outgoing_bind_address \ + evutil_secure_rng_set_urandom_device_file \ + event_base_loopexit]) AC_CHECK_MEMBERS([struct event.min_heap_idx], , , [#include <event.h> ]) diff --git a/src/common/address.c b/src/common/address.c index 227b4fbae..945e5e79b 100644 --- a/src/common/address.c +++ b/src/common/address.c @@ -14,6 +14,7 @@ #include "address.h" #include "torlog.h" #include "container.h" +#include "sandbox.h" #ifdef _WIN32 #include <process.h> @@ -234,7 +235,7 @@ tor_addr_lookup(const char *name, uint16_t family, tor_addr_t *addr) memset(&hints, 0, sizeof(hints)); hints.ai_family = family; hints.ai_socktype = SOCK_STREAM; - err = getaddrinfo(name, NULL, &hints, &res); + err = sandbox_getaddrinfo(name, NULL, &hints, &res); if (!err) { best = NULL; for (res_p = res; res_p; res_p = res_p->ai_next) { diff --git a/src/common/compat.c b/src/common/compat.c index d6ea41878..8e2619f84 100644 --- a/src/common/compat.c +++ b/src/common/compat.c @@ -110,6 +110,7 @@ #include "util.h" #include "container.h" #include "address.h" +#include "sandbox.h" /* Inline the strl functions if the platform doesn't have them. */ #ifndef HAVE_STRLCPY @@ -126,6 +127,7 @@ tor_open_cloexec(const char *path, int flags, unsigned mode) { int fd; #ifdef O_CLOEXEC + path = sandbox_intern_string(path); fd = open(path, flags|O_CLOEXEC, mode); if (fd >= 0) return fd; diff --git a/src/common/crypto.c b/src/common/crypto.c index 6f1a0bca5..684949964 100644 --- a/src/common/crypto.c +++ b/src/common/crypto.c @@ -56,6 +56,7 @@ #include "../common/util.h" #include "container.h" #include "compat.h" +#include "sandbox.h" #if OPENSSL_VERSION_NUMBER < OPENSSL_V_SERIES(0,9,8) #error "We require OpenSSL >= 0.9.8" @@ -2349,7 +2350,7 @@ crypto_strongest_rand(uint8_t *out, size_t out_len) return 0; #else for (i = 0; filenames[i]; ++i) { - fd = open(filenames[i], O_RDONLY, 0); + fd = open(sandbox_intern_string(filenames[i]), O_RDONLY, 0); if (fd<0) continue; log_info(LD_CRYPTO, "Reading entropy from \"%s\"", filenames[i]); n = read_all(fd, (char*)out, out_len, 0); diff --git a/src/common/sandbox.c b/src/common/sandbox.c index dbb1657cd..33ffd3356 100644 --- a/src/common/sandbox.c +++ b/src/common/sandbox.c @@ -9,53 +9,79 @@ * \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 + +/** Malloc mprotect limit in bytes. */ +#define MALLOC_MP_LIM 1048576 + #include <stdio.h> #include <string.h> #include <stdlib.h> -#include "orconfig.h" #include "sandbox.h" #include "torlog.h" +#include "torint.h" #include "util.h" - -#if defined(HAVE_SECCOMP_H) && defined(__linux__) -#define USE_LIBSECCOMP -#endif +#include "tor_queue.h" #define DEBUGGING_CLOSE #if defined(USE_LIBSECCOMP) +#define _GNU_SOURCE + +#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 <bits/signum.h> +#include <event2/event.h> + +#include <stdarg.h> #include <seccomp.h> #include <signal.h> #include <unistd.h> +#include <fcntl.h> +#include <time.h> +#include <poll.h> + +/**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; +/** Holds a list of pre-recorded results from getaddrinfo().*/ +static sb_addr_info_t *sb_addr_info = NULL; + +#undef SCMP_CMP +#define SCMP_CMP(a,b,c) ((struct scmp_arg_cmp){(a),(b),(c),0}) /** Variable used for storing all syscall numbers that will be allowed with the * stage 1 general Tor sandbox. */ -static int general_filter[] = { +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_ctl), SCMP_SYS(epoll_wait), - SCMP_SYS(execve), SCMP_SYS(fcntl), -#ifdef __NR_fcntl64 - /* Older libseccomp versions don't define PNR entries for all of these, - * so we need to ifdef them here.*/ - SCMP_SYS(fcntl64), -#endif - SCMP_SYS(flock), SCMP_SYS(fstat), #ifdef __NR_fstat64 SCMP_SYS(fstat64), #endif - SCMP_SYS(futex), SCMP_SYS(getdents64), SCMP_SYS(getegid), #ifdef __NR_getegid32 @@ -82,76 +108,1161 @@ static int general_filter[] = { SCMP_SYS(mkdir), SCMP_SYS(mlockall), SCMP_SYS(mmap), -#ifdef __NR_mmap2 - SCMP_SYS(mmap2), -#endif - SCMP_SYS(mprotect), - SCMP_SYS(mremap), SCMP_SYS(munmap), - SCMP_SYS(open), - SCMP_SYS(openat), - SCMP_SYS(poll), - SCMP_SYS(prctl), SCMP_SYS(read), SCMP_SYS(rename), - SCMP_SYS(rt_sigaction), - SCMP_SYS(rt_sigprocmask), SCMP_SYS(rt_sigreturn), + SCMP_SYS(set_robust_list), #ifdef __NR_sigreturn SCMP_SYS(sigreturn), #endif - SCMP_SYS(set_robust_list), - SCMP_SYS(set_thread_area), - SCMP_SYS(set_tid_address), SCMP_SYS(stat), -#ifdef __NR_stat64 - SCMP_SYS(stat64), -#endif - SCMP_SYS(time), SCMP_SYS(uname), SCMP_SYS(write), SCMP_SYS(exit_group), SCMP_SYS(exit), + SCMP_SYS(madvise), +#ifdef __NR_stat64 + // getaddrinfo uses this.. + SCMP_SYS(stat64), +#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(accept4), SCMP_SYS(bind), SCMP_SYS(connect), SCMP_SYS(getsockname), - SCMP_SYS(getsockopt), - SCMP_SYS(listen), -#if __NR_recv >= 0 - /* This is a kludge; It's necessary on 64-bit with libseccomp 1.0.0; I - * don't know if other 64-bit or other versions require it. */ - SCMP_SYS(recv), -#endif SCMP_SYS(recvmsg), -#if __NR_send >= 0 - SCMP_SYS(send), -#endif + SCMP_SYS(recvfrom), SCMP_SYS(sendto), - SCMP_SYS(setsockopt), - SCMP_SYS(socket), - SCMP_SYS(socketpair), + SCMP_SYS(unlink) +}; - // TODO: remove when accept4 is fixed -#ifdef __NR_socketcall - SCMP_SYS(socketcall), +/** + * 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; - SCMP_SYS(recvfrom), - SCMP_SYS(unlink) + for (i = 0; i < ARRAY_LENGTH(param); i++) { + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(rt_sigaction), 1, + SCMP_CMP(0, SCMP_CMP_EQ, param[i])); + if (rc) + break; + } + + return rc; +} + +/** + * Function responsible for setting up the execve syscall for + * the seccomp filter sandbox. + */ +static int +sb_execve(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 = (smp_param_t*) elem->param; + + if (param != NULL && param->prot == 1 && param->syscall + == SCMP_SYS(execve)) { + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(execve), 1, + SCMP_CMP(0, SCMP_CMP_EQ, param->value)); + if (rc != 0) { + log_err(LD_BUG,"(Sandbox) failed to add execve syscall, received " + "libseccomp error %d", rc); + return rc; + } + } + } + + return 0; +} + +/** + * 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; + return seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(time), 1, + SCMP_CMP(0, SCMP_CMP_EQ, 0)); +} + +/** + * 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socketcall), 1, + SCMP_CMP(0, SCMP_CMP_EQ, 18)); + if (rc) { + return rc; + } +#endif + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(accept4), 1, + SCMP_CMP(3, SCMP_CMP_EQ, SOCK_CLOEXEC)); + 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; + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mmap2), 2, + SCMP_CMP(2, SCMP_CMP_EQ, PROT_READ), + SCMP_CMP(3, SCMP_CMP_EQ, MAP_PRIVATE)); + if (rc) { + return rc; + } + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mmap2), 2, + 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mmap2), 2, + 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mmap2), 2, + 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mmap2), 2, + 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mmap2), 2, + 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mmap2), 2, + 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 + +/** + * 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; + + // 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 = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(open), 1, + SCMP_CMP(0, SCMP_CMP_EQ, 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(ctx, SCMP_ACT_ERRNO(-1), SCMP_SYS(open), 1, + SCMP_CMP(1, SCMP_CMP_EQ, O_RDONLY|O_CLOEXEC)); + if (rc != 0) { + log_err(LD_BUG,"(Sandbox) failed to add open 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(openat), 1, + SCMP_CMP(0, SCMP_CMP_EQ, AT_FDCWD), + SCMP_CMP(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; + (void) filter; + +#ifdef __i386__ + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket), 0); + if (rc) + return rc; +#endif + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket), 3, + SCMP_CMP(0, SCMP_CMP_EQ, PF_FILE), + SCMP_CMP(1, SCMP_CMP_EQ, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK), + SCMP_CMP(2, SCMP_CMP_EQ, IPPROTO_IP)); + if (rc) + return rc; + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket), 3, + SCMP_CMP(0, SCMP_CMP_EQ, PF_INET), + SCMP_CMP(1, SCMP_CMP_EQ, SOCK_STREAM|SOCK_CLOEXEC), + SCMP_CMP(2, SCMP_CMP_EQ, IPPROTO_TCP)); + if (rc) + return rc; + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket), 3, + SCMP_CMP(0, SCMP_CMP_EQ, PF_INET), + SCMP_CMP(1, SCMP_CMP_EQ, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK), + SCMP_CMP(2, SCMP_CMP_EQ, IPPROTO_IP)); + if (rc) + return rc; + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket), 3, + SCMP_CMP(0, SCMP_CMP_EQ, PF_NETLINK), + SCMP_CMP(1, SCMP_CMP_EQ, 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socketpair), 0); + if (rc) + return rc; +#endif + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socketpair), 2, + SCMP_CMP(0, SCMP_CMP_EQ, PF_FILE), + SCMP_CMP(1, SCMP_CMP_EQ, SOCK_STREAM|SOCK_CLOEXEC)); + if (rc) + return rc; + + return 0; +} + +/** + * 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(setsockopt), 0); + if (rc) + return rc; +#endif + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(setsockopt), 2, + SCMP_CMP(1, SCMP_CMP_EQ, SOL_SOCKET), + SCMP_CMP(2, SCMP_CMP_EQ, SO_REUSEADDR)); + if (rc) + return rc; + + 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(getsockopt), 0); + if (rc) + return rc; +#endif + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(getsockopt), 2, + SCMP_CMP(1, SCMP_CMP_EQ, SOL_SOCKET), + SCMP_CMP(2, SCMP_CMP_EQ, SO_ERROR)); + if (rc) + return rc; + + 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; + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl64), 1, + SCMP_CMP(1, SCMP_CMP_EQ, F_GETFL)); + if (rc) + return rc; + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl64), 2, + 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl64), 1, + SCMP_CMP(1, SCMP_CMP_EQ, F_GETFD)); + if (rc) + return rc; + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(fcntl64), 2, + SCMP_CMP(1, SCMP_CMP_EQ, F_SETFD), + SCMP_CMP(2, SCMP_CMP_EQ, FD_CLOEXEC)); + if (rc) + return rc; + + return 0; +} +#endif + +/** + * 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(epoll_ctl), 1, + SCMP_CMP(1, SCMP_CMP_EQ, EPOLL_CTL_ADD)); + if (rc) + return rc; + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(epoll_ctl), 1, + SCMP_CMP(1, SCMP_CMP_EQ, EPOLL_CTL_MOD)); + if (rc) + return rc; + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(epoll_ctl), 1, + SCMP_CMP(1, SCMP_CMP_EQ, EPOLL_CTL_DEL)); + if (rc) + return rc; + + return 0; +} + +/** + * Function responsible for setting up the fcntl64 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(prctl), 1, + SCMP_CMP(0, SCMP_CMP_EQ, PR_SET_DUMPABLE)); + if (rc) + return rc; + + return 0; +} + +/** + * Function responsible for setting up the fcntl64 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mprotect), 1, + SCMP_CMP(2, SCMP_CMP_EQ, PROT_READ)); + if (rc) + return rc; + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mprotect), 1, + 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(rt_sigprocmask), 1, + SCMP_CMP(0, SCMP_CMP_EQ, SIG_UNBLOCK)); + if (rc) + return rc; + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(rt_sigprocmask), 1, + 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(flock), 1, + SCMP_CMP(1, SCMP_CMP_EQ, LOCK_EX|LOCK_NB)); + if (rc) + return rc; + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(flock), 1, + 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(futex), 1, + SCMP_CMP(1, SCMP_CMP_EQ, + FUTEX_WAIT_BITSET_PRIVATE|FUTEX_CLOCK_REALTIME)); + if (rc) + return rc; + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(futex), 1, + SCMP_CMP(1, SCMP_CMP_EQ, FUTEX_WAKE_PRIVATE)); + if (rc) + return rc; + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(futex), 1, + 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mremap), 1, + SCMP_CMP(3, SCMP_CMP_EQ, MREMAP_MAYMOVE)); + if (rc) + return rc; + + return 0; +} + +/** + * Function responsible for setting up the poll syscall for + * the seccomp filter sandbox. + */ +static int +sb_poll(scmp_filter_ctx ctx, sandbox_cfg_t *filter) +{ + int rc = 0; + (void) filter; + + rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(poll), 2, + SCMP_CMP(1, SCMP_CMP_EQ, 1), + SCMP_CMP(2, SCMP_CMP_EQ, 10)); + 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(stat64), 1, + SCMP_CMP(0, SCMP_CMP_EQ, param->value)); + if (rc != 0) { + log_err(LD_BUG,"(Sandbox) failed to add open syscall, received " + "libseccomp error %d", rc); + return rc; + } + } + } + + return 0; +} +#endif + +/** + * 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_execve, + sb_time, + sb_accept4, +#ifdef __NR_mmap2 + sb_mmap2, +#endif + sb_open, + sb_openat, +#ifdef __NR_fcntl64 + sb_fcntl64, +#endif + sb_epoll_ctl, + sb_prctl, + sb_mprotect, + sb_flock, + sb_futex, + sb_mremap, + sb_poll, +#ifdef __NR_stat64 + sb_stat64, +#endif + + sb_socket, + sb_setsockopt, + sb_getsockopt, + sb_socketpair }; +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 && !strcmp(str, (char*)(param->value))) { + return (char*)(param->value); + } + } + + log_info(LD_GENERAL, "(Sandbox) Parameter %s not found", str); + return str; +} + +/** + * 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; + + // get total number of bytes required to mmap + for (el = cfg; el != NULL; el = el->next) { + pr_mem_size += strlen((char*) ((smp_param_t*)el->param)->value) + 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; + + // change el value pointer to protected + for (el = cfg; el != NULL; el = el->next) { + char *param_val = (char*)((smp_param_t *)el->param)->value; + size_t param_size = strlen(param_val) + 1; + + if (pr_mem_left >= param_size) { + // copy to protected + memcpy(pr_mem_next, param_val, param_size); + + // re-point el parameter to protected + { + void *old_val = (void *) ((smp_param_t*)el->param)->value; + tor_free(old_val); + } + ((smp_param_t*)el->param)->value = (intptr_t) pr_mem_next; + ((smp_param_t*)el->param)->prot = 1; + + // move next available protected memory + pr_mem_next += param_size; + pr_mem_left -= param_size; + } else { + log_err(LD_BUG,"(Sandbox) insufficient protected memory!"); + ret = -2; + goto out; + } + } + + // 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(ctx, SCMP_ACT_KILL, SCMP_SYS(mremap), 1, + SCMP_CMP(0, SCMP_CMP_EQ, (intptr_t) pr_mem_base)); + if (ret) { + log_err(LD_BUG,"(Sandbox) mremap protected memory filter fail!"); + return ret; + } + + // no munmap of the protected base address + ret = seccomp_rule_add(ctx, SCMP_ACT_KILL, SCMP_SYS(munmap), 1, + SCMP_CMP(0, SCMP_CMP_EQ, (intptr_t) pr_mem_base)); + if (ret) { + log_err(LD_BUG,"(Sandbox) munmap protected memory filter fail!"); + return ret; + } + + /* + * 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(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mprotect), 2, + 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)!"); + return ret; + } + + ret = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(mprotect), 2, + 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)!"); + return ret; + } + + out: + return ret; +} + +/** + * Auxiliary function used in order to allocate a sandbox_cfg_t element and set + * it's values according the 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_element(int syscall, int index, intptr_t value) +{ + smp_param_t *param = NULL; + + sandbox_cfg_t *elem = (sandbox_cfg_t*) tor_malloc(sizeof(sandbox_cfg_t)); + if (!elem) + return NULL; + + elem->param = (smp_param_t*) tor_malloc(sizeof(smp_param_t)); + if (!elem->param) { + tor_free(elem); + return NULL; + } + + param = elem->param; + param->syscall = syscall; + param->pindex = index; + param->value = value; + param->prot = 0; + + return elem; +} + +#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, int fr) +{ + sandbox_cfg_t *elem = NULL; + + elem = new_element(SCMP_stat, 0, (intptr_t)(void*) tor_strdup(file)); + if (!elem) { + log_err(LD_BUG,"(Sandbox) failed to register parameter!"); + return -1; + } + + elem->next = *cfg; + *cfg = elem; + + if (fr) tor_free(file); + return 0; +} + +int +sandbox_cfg_allow_stat_filename_array(sandbox_cfg_t **cfg, ...) +{ + int rc = 0; + char *fn = NULL; + + va_list ap; + va_start(ap, cfg); + + while ((fn = va_arg(ap, char*)) != NULL) { + int fr = va_arg(ap, int); + + rc = sandbox_cfg_allow_stat_filename(cfg, fn, fr); + if (rc) { + log_err(LD_BUG,"(Sandbox) sandbox_cfg_allow_stat_filename_array fail"); + goto end; + } + } + + end: + va_end(ap); + return 0; +} + +int +sandbox_cfg_allow_open_filename(sandbox_cfg_t **cfg, char *file, int fr) +{ + sandbox_cfg_t *elem = NULL; + + elem = new_element(SCMP_SYS(open), 0, (intptr_t)(void *)tor_strdup(file)); + if (!elem) { + log_err(LD_BUG,"(Sandbox) failed to register parameter!"); + return -1; + } + + elem->next = *cfg; + *cfg = elem; + + if (fr) tor_free(file); + + return 0; +} + +int +sandbox_cfg_allow_open_filename_array(sandbox_cfg_t **cfg, ...) +{ + int rc = 0; + char *fn = NULL; + + va_list ap; + va_start(ap, cfg); + + while ((fn = va_arg(ap, char*)) != NULL) { + int fr = va_arg(ap, int); + + rc = sandbox_cfg_allow_open_filename(cfg, fn, fr); + if (rc) { + log_err(LD_BUG,"(Sandbox) sandbox_cfg_allow_open_filename_array fail"); + goto end; + } + } + + end: + va_end(ap); + return 0; +} + +int +sandbox_cfg_allow_openat_filename(sandbox_cfg_t **cfg, char *file, int fr) +{ + sandbox_cfg_t *elem = NULL; + + elem = new_element(SCMP_SYS(openat), 1, (intptr_t)(void *)tor_strdup(file)); + if (!elem) { + log_err(LD_BUG,"(Sandbox) failed to register parameter!"); + return -1; + } + + elem->next = *cfg; + *cfg = elem; + + if (fr) tor_free(file); + + return 0; +} + +int +sandbox_cfg_allow_openat_filename_array(sandbox_cfg_t **cfg, ...) +{ + int rc = 0; + char *fn = NULL; + + va_list ap; + va_start(ap, cfg); + + while ((fn = va_arg(ap, char*)) != NULL) { + int fr = va_arg(ap, int); + + rc = sandbox_cfg_allow_openat_filename(cfg, fn, fr); + if (rc) { + log_err(LD_BUG,"(Sandbox) sandbox_cfg_allow_openat_filename_array fail"); + goto end; + } + } + + end: + va_end(ap); + return 0; +} + +int +sandbox_cfg_allow_execve(sandbox_cfg_t **cfg, const char *com) +{ + sandbox_cfg_t *elem = NULL; + + elem = new_element(SCMP_SYS(execve), 1, (intptr_t)(void *)tor_strdup(com)); + if (!elem) { + log_err(LD_BUG,"(Sandbox) failed to register parameter!"); + return -1; + } + + elem->next = *cfg; + *cfg = elem; + + return 0; +} + +int +sandbox_cfg_allow_execve_array(sandbox_cfg_t **cfg, ...) +{ + int rc = 0; + char *fn = NULL; + + va_list ap; + va_start(ap, cfg); + + while ((fn = va_arg(ap, char*)) != NULL) { + + rc = sandbox_cfg_allow_execve(cfg, fn); + if (rc) { + log_err(LD_BUG,"(Sandbox) sandbox_cfg_allow_execve_array failed"); + goto end; + } + } + + end: + va_end(ap); + return 0; +} + +int +sandbox_getaddrinfo(const char *name, const char *servname, + const struct addrinfo *hints, + struct addrinfo **res) +{ + sb_addr_info_t *el; + + if (servname != NULL) + return -1; + + *res = NULL; + + for (el = sb_addr_info; el; el = el->next) { + if (!strcmp(el->name, name)) { + *res = (struct addrinfo *) tor_malloc(sizeof(struct addrinfo)); + if (!res) { + return -2; + } + + memcpy(*res, el->info, sizeof(struct addrinfo)); + return 0; + } + } + + if (!sandbox_active) { + if (getaddrinfo(name, NULL, hints, res)) { + log_err(LD_BUG,"(Sandbox) getaddrinfo failed!"); + return -1; + } + + return 0; + } + + // getting here means something went wrong + log_err(LD_BUG,"(Sandbox) failed to get address %s!", name); + if (*res) { + tor_free(*res); + res = NULL; + } + return -1; +} + +int +sandbox_add_addrinfo(const char* name) +{ + int ret; + struct addrinfo hints; + sb_addr_info_t *el = NULL; + + el = (sb_addr_info_t*) tor_malloc(sizeof(sb_addr_info_t)); + if (!el) { + log_err(LD_BUG,"(Sandbox) failed to allocate addr info!"); + ret = -2; + goto out; + } + + memset(&hints, 0, sizeof(hints)); + hints.ai_family = AF_INET; + hints.ai_socktype = SOCK_STREAM; + + ret = getaddrinfo(name, NULL, &hints, &(el->info)); + if (ret) { + log_err(LD_BUG,"(Sandbox) failed to getaddrinfo"); + ret = -2; + goto out; + } + + el->name = tor_strdup(name); + el->next = sb_addr_info; + sb_addr_info = el; + + out: + return ret; +} + +/** + * 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++) { + if ((filter_func[i])(ctx, cfg)) { + 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(ctx, SCMP_ACT_ALLOW, filter_nopar_gen[i], 0); + 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_glob_syscall_filter(void) +install_syscall_filter(sandbox_cfg_t* cfg) { - int rc = 0, i, filter_size; + int rc = 0; scmp_filter_ctx ctx; ctx = seccomp_init(SCMP_ACT_TRAP); @@ -161,23 +1272,31 @@ install_glob_syscall_filter(void) goto end; } - if (general_filter != NULL) { - filter_size = sizeof(general_filter) / sizeof(general_filter[0]); - } else { - filter_size = 0; + // protectign sandbox parameter strings + if ((rc = prot_strings(ctx, cfg))) { + goto end; } - // add general filters - for (i = 0; i < filter_size; i++) { - rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, general_filter[i], 0); - if (rc != 0) { - log_err(LD_BUG,"(Sandbox) failed to add syscall index %d, " - "received libseccomp error %d", i, rc); - 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!"); + goto end; } - rc = seccomp_load(ctx); + // marking the sandbox as active + sandbox_active = 1; end: seccomp_release(ctx); @@ -269,6 +1388,29 @@ install_sigsys_debugging(void) 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 // USE_LIBSECCOMP #ifdef USE_LIBSECCOMP @@ -277,48 +1419,53 @@ install_sigsys_debugging(void) * into account various available features for different linux flavours. */ static int -initialise_libseccomp_sandbox(void) +initialise_libseccomp_sandbox(sandbox_cfg_t* cfg) { if (install_sigsys_debugging()) return -1; - if (install_glob_syscall_filter()) + if (install_syscall_filter(cfg)) return -2; + if (register_cfg(cfg)) + return -3; + return 0; } #endif // USE_LIBSECCOMP -/** - * Enables the stage 1 general sandbox. It applies a syscall filter which does - * not restrict any Tor features. The filter is representative for the whole - * application. - */ -int -tor_global_sandbox(void) +sandbox_cfg_t* +sandbox_cfg_new(void) { + return NULL; +} +int +sandbox_init(sandbox_cfg_t *cfg) +{ #if defined(USE_LIBSECCOMP) - return initialise_libseccomp_sandbox(); + return initialise_libseccomp_sandbox(cfg); #elif defined(_WIN32) + (void)cfg; log_warn(LD_BUG,"Windows sandboxing is not implemented. The feature is " "currently disabled."); return 0; #elif defined(TARGET_OS_MAC) + (void)cfg; log_warn(LD_BUG,"Mac OSX sandboxing is not implemented. The feature is " "currently disabled"); return 0; #else + (void)cfg; log_warn(LD_BUG,"Sandboxing is not implemented for your platform. The " "feature is currently disabled"); return 0; #endif } -/** Use <b>fd</b> to log non-survivable sandbox violations. */ void sandbox_set_debugging_fd(int fd) { @@ -329,3 +1476,64 @@ sandbox_set_debugging_fd(int fd) #endif } +#ifndef USE_LIBSECCOMP +int +sandbox_cfg_allow_open_filename(sandbox_cfg_t **cfg, char *file, + int fr) +{ + (void)cfg; (void)file; (void)fr; + return 0; +} + +int +sandbox_cfg_allow_open_filename_array(sandbox_cfg_t **cfg, ...) +{ + (void)cfg; + return 0; +} + +int +sandbox_cfg_allow_openat_filename(sandbox_cfg_t **cfg, char *file, + int fr) +{ + (void)cfg; (void)file; (void)fr; + return 0; +} + +int +sandbox_cfg_allow_openat_filename_array(sandbox_cfg_t **cfg, ...) +{ + (void)cfg; + return 0; +} + +int +sandbox_cfg_allow_execve(sandbox_cfg_t **cfg, const char *com) +{ + (void)cfg; (void)com; + return 0; +} + +int +sandbox_cfg_allow_execve_array(sandbox_cfg_t **cfg, ...) +{ + (void)cfg; + return 0; +} + +int +sandbox_cfg_allow_stat_filename(sandbox_cfg_t **cfg, char *file, + int fr) +{ + (void)cfg; (void)file; (void)fr; + return 0; +} + +int +sandbox_cfg_allow_stat_filename_array(sandbox_cfg_t **cfg, ...) +{ + (void)cfg; + return 0; +} +#endif + diff --git a/src/common/sandbox.h b/src/common/sandbox.h index bd6f0cfb4..1d39be409 100644 --- a/src/common/sandbox.h +++ b/src/common/sandbox.h @@ -12,6 +12,9 @@ #ifndef SANDBOX_H_ #define SANDBOX_H_ +#include "orconfig.h" +#include "torint.h" + #ifndef SYS_SECCOMP /** @@ -22,13 +25,99 @@ #endif +#if defined(HAVE_SECCOMP_H) && defined(__linux__) +#define USE_LIBSECCOMP +#endif + +struct sandbox_cfg_elem; + +/** Typedef to structure used to manage a sandbox configuration. */ +typedef struct sandbox_cfg_elem sandbox_cfg_t; + /** * Linux definitions */ -#ifdef __linux__ +#ifdef USE_LIBSECCOMP +#ifndef __USE_GNU #define __USE_GNU +#endif #include <sys/ucontext.h> +#include <seccomp.h> +#include <netdb.h> + +#define PARAM_PTR 0 +#define PARAM_NUM 1 + +/** + * Enum used to manage the type of the implementation for general purpose. + */ +typedef enum { + /** Libseccomp implementation based on seccomp2*/ + LIBSECCOMP2 = 0 +} SB_IMPL; + +/** + * Configuration parameter structure associated with the LIBSECCOMP2 + * implementation. + */ +typedef struct smp_param { + /** syscall associated with parameter. */ + int syscall; + + /** parameter index. */ + int pindex; + /** parameter value. */ + intptr_t value; + + /** parameter flag (0 = not protected, 1 = protected). */ + int prot; +} smp_param_t; + +/** + * Structure used to manage a sandbox configuration. + * + * It is implemented as a linked list of parameters. Currently only controls + * parameters for open, openat, execve, stat64. + */ +struct sandbox_cfg_elem { + /** Sandbox implementation which dictates the parameter type. */ + SB_IMPL implem; + + /** Configuration parameter. */ + void *param; + + /** Next element of the configuration*/ + struct sandbox_cfg_elem *next; +}; + +/** + * Structure used for keeping a linked list of getaddrinfo pre-recorded + * results. + */ +struct sb_addr_info_el { + /** Name of the address info result. */ + char *name; + /** Pre-recorded getaddrinfo result. */ + struct addrinfo *info; + /** Next element in the list. */ + struct sb_addr_info_el *next; +}; +/** Typedef to structure used to manage an addrinfo list. */ +typedef struct sb_addr_info_el sb_addr_info_t; + +/** Function pointer defining the prototype of a filter function.*/ +typedef int (*sandbox_filter_func_t)(scmp_filter_ctx ctx, + sandbox_cfg_t *filter); + +/** Type that will be used in step 3 in order to manage multiple sandboxes.*/ +typedef struct { + /** function pointers associated with the filter */ + sandbox_filter_func_t *filter_func; + + /** filter function pointer parameters */ + sandbox_cfg_t *filter_dynamic; +} sandbox_t; /** * Linux 32 bit definitions @@ -46,10 +135,116 @@ #endif -#endif // __linux__ +#endif // USE_LIBSECCOMP + +#ifdef USE_LIBSECCOMP +/** Pre-calls getaddrinfo in order to pre-record result. */ +int sandbox_add_addrinfo(const char *addr); + +struct addrinfo; +/** Replacement for getaddrinfo(), using pre-recorded results. */ +int sandbox_getaddrinfo(const char *name, const char *servname, + const struct addrinfo *hints, + struct addrinfo **res); +#else +#define sandbox_getaddrinfo(name, servname, hints, res) \ + getaddrinfo((name),(servname), (hints),(res)) +#define sandbox_add_addrinfo(name) \ + ((void)(name)) +#endif +/** Use <b>fd</b> to log non-survivable sandbox violations. */ void sandbox_set_debugging_fd(int fd); -int tor_global_sandbox(void); + +#ifdef USE_LIBSECCOMP +/** Returns a registered protected string used with the sandbox, given that + * it matches the parameter. + */ +const char* sandbox_intern_string(const char *param); +#else +#define sandbox_intern_string(s) (s) +#endif + +/** Creates an empty sandbox configuration file.*/ +sandbox_cfg_t * sandbox_cfg_new(void); + +/** + * Function used to add a open allowed filename to a supplied configuration. + * The (char*) specifies the path to the allowed file, fr = 1 tells the + * function that the char* needs to be free-ed, 0 means the pointer does not + * need to be free-ed. + */ +int sandbox_cfg_allow_open_filename(sandbox_cfg_t **cfg, char *file, + int fr); + +/** Function used to add a series of open allowed filenames to a supplied + * configuration. + * @param cfg sandbox configuration. + * @param ... all future parameters are specified as pairs of <(char*), 1 / 0> + * the char* specifies the path to the allowed file, 1 tells the function + * that the char* needs to be free-ed, 0 means the pointer does not need to + * be free-ed; the final parameter needs to be <NULL, 0>. + */ +int sandbox_cfg_allow_open_filename_array(sandbox_cfg_t **cfg, ...); + +/** + * Function used to add a openat allowed filename to a supplied configuration. + * The (char*) specifies the path to the allowed file, fr = 1 tells the + * function that the char* needs to be free-ed, 0 means the pointer does not + * need to be free-ed. + */ +int sandbox_cfg_allow_openat_filename(sandbox_cfg_t **cfg, char *file, + int fr); + +/** Function used to add a series of openat allowed filenames to a supplied + * configuration. + * @param cfg sandbox configuration. + * @param ... all future parameters are specified as pairs of <(char*), 1 / 0> + * the char* specifies the path to the allowed file, 1 tells the function + * that the char* needs to be free-ed, 0 means the pointer does not need to + * be free-ed; the final parameter needs to be <NULL, 0>. + */ +int sandbox_cfg_allow_openat_filename_array(sandbox_cfg_t **cfg, ...); + +/** + * Function used to add a execve allowed filename to a supplied configuration. + * The (char*) specifies the path to the allowed file, fr = 1 tells the + * function that the char* needs to be free-ed, 0 means the pointer does not + * need to be free-ed. + */ +int sandbox_cfg_allow_execve(sandbox_cfg_t **cfg, const char *com); + +/** Function used to add a series of execve allowed filenames to a supplied + * configuration. + * @param cfg sandbox configuration. + * @param ... all future parameters are specified as pairs of <(char*), 1 / 0> + * the char* specifies the path to the allowed file, 1 tells the function + * that the char* needs to be free-ed, 0 means the pointer does not need to + * be free-ed; the final parameter needs to be <NULL, 0>. + */ +int sandbox_cfg_allow_execve_array(sandbox_cfg_t **cfg, ...); + +/** + * Function used to add a stat/stat64 allowed filename to a configuration. + * The (char*) specifies the path to the allowed file, fr = 1 tells the + * function that the char* needs to be free-ed, 0 means the pointer does not + * need to be free-ed. + */ +int sandbox_cfg_allow_stat_filename(sandbox_cfg_t **cfg, char *file, + int fr); + +/** Function used to add a series of stat64 allowed filenames to a supplied + * configuration. + * @param cfg sandbox configuration. + * @param ... all future parameters are specified as pairs of <(char*), 1 / 0> + * the char* specifies the path to the allowed file, 1 tells the function + * that the char* needs to be free-ed, 0 means the pointer does not need to + * be free-ed; the final parameter needs to be <NULL, 0>. + */ +int sandbox_cfg_allow_stat_filename_array(sandbox_cfg_t **cfg, ...); + +/** Function used to initialise a sandbox configuration.*/ +int sandbox_init(sandbox_cfg_t* cfg); #endif /* SANDBOX_H_ */ diff --git a/src/common/util.c b/src/common/util.c index 6e14a58dd..02c51a451 100644 --- a/src/common/util.c +++ b/src/common/util.c @@ -24,6 +24,7 @@ #include "torint.h" #include "container.h" #include "address.h" +#include "../common/sandbox.h" #ifdef _WIN32 #include <io.h> @@ -1799,7 +1800,7 @@ file_status(const char *fname) int r; f = tor_strdup(fname); clean_name_for_stat(f); - r = stat(f, &st); + r = stat(sandbox_intern_string(f), &st); tor_free(f); if (r) { if (errno == ENOENT) { @@ -1849,7 +1850,7 @@ check_private_dir(const char *dirname, cpd_check_t check, tor_assert(dirname); f = tor_strdup(dirname); clean_name_for_stat(f); - r = stat(f, &st); + r = stat(sandbox_intern_string(f), &st); tor_free(f); if (r) { if (errno != ENOENT) { @@ -3039,6 +3040,7 @@ smartlist_t * tor_listdir(const char *dirname) { smartlist_t *result; + const char *prot_dname = sandbox_intern_string(dirname); #ifdef _WIN32 char *pattern=NULL; TCHAR tpattern[MAX_PATH] = {0}; @@ -3082,7 +3084,7 @@ tor_listdir(const char *dirname) #else DIR *d; struct dirent *de; - if (!(d = opendir(dirname))) + if (!(d = opendir(prot_dname))) return NULL; result = smartlist_new(); diff --git a/src/common/util.h b/src/common/util.h index 090243ea2..fdd8c135a 100644 --- a/src/common/util.h +++ b/src/common/util.h @@ -542,5 +542,7 @@ STATIC int format_helper_exit_status(unsigned char child_state, const char *libor_get_digests(void); +#define ARRAY_LENGTH(x) (sizeof(x)) / sizeof(x[0]) + #endif diff --git a/src/or/config.c b/src/or/config.c index 37b42e891..17d672885 100644 --- a/src/or/config.c +++ b/src/or/config.c @@ -6301,7 +6301,8 @@ remove_file_if_very_old(const char *fname, time_t now) #define VERY_OLD_FILE_AGE (28*24*60*60) struct stat st; - if (stat(fname, &st)==0 && st.st_mtime < now-VERY_OLD_FILE_AGE) { + if (stat(sandbox_intern_string(fname), &st)==0 && + st.st_mtime < now-VERY_OLD_FILE_AGE) { char buf[ISO_TIME_LEN+1]; format_local_iso_time(buf, st.st_mtime); log_notice(LD_GENERAL, "Obsolete file %s hasn't been modified since %s. " diff --git a/src/or/dns.c b/src/or/dns.c index f2b7eecc3..62ee4f372 100644 --- a/src/or/dns.c +++ b/src/or/dns.c @@ -24,6 +24,7 @@ #include "relay.h" #include "router.h" #include "ht.h" +#include "../common/sandbox.h" #ifdef HAVE_EVENT2_DNS_H #include <event2/event.h> #include <event2/dns.h> @@ -1443,13 +1444,14 @@ configure_nameservers(int force) const or_options_t *options; const char *conf_fname; struct stat st; - int r; + int r, flags; options = get_options(); conf_fname = options->ServerDNSResolvConfFile; #ifndef _WIN32 if (!conf_fname) conf_fname = "/etc/resolv.conf"; #endif + flags = DNS_OPTIONS_ALL; if (!the_evdns_base) { if (!(the_evdns_base = evdns_base_new(tor_libevent_get_base(), 0))) { @@ -1477,7 +1479,7 @@ configure_nameservers(int force) evdns_set_log_fn(evdns_log_cb); if (conf_fname) { - if (stat(conf_fname, &st)) { + if (stat(sandbox_intern_string(conf_fname), &st)) { log_warn(LD_EXIT, "Unable to stat resolver configuration in '%s': %s", conf_fname, strerror(errno)); goto err; @@ -1491,9 +1493,14 @@ configure_nameservers(int force) evdns_base_search_clear(the_evdns_base); evdns_base_clear_nameservers_and_suspend(the_evdns_base); } + if (flags & DNS_OPTION_HOSTSFILE) { + flags ^= DNS_OPTION_HOSTSFILE; + evdns_base_load_hosts(the_evdns_base, + sandbox_intern_string("/etc/resolv.conf")); + } log_info(LD_EXIT, "Parsing resolver configuration in '%s'", conf_fname); - if ((r = evdns_base_resolv_conf_parse(the_evdns_base, - DNS_OPTIONS_ALL, conf_fname))) { + if ((r = evdns_base_resolv_conf_parse(the_evdns_base, flags, + sandbox_intern_string(conf_fname)))) { log_warn(LD_EXIT, "Unable to parse '%s', or no nameservers in '%s' (%d)", conf_fname, conf_fname, r); goto err; diff --git a/src/or/main.c b/src/or/main.c index 40e8377a9..fa112437f 100644 --- a/src/or/main.c +++ b/src/or/main.c @@ -2655,6 +2655,95 @@ find_flashcard_path(PWCHAR path, size_t size) } #endif +static void +init_addrinfo(void) +{ + char hname[256]; + + // host name to sandbox + gethostname(hname, sizeof(hname)); + sandbox_add_addrinfo(hname); +} + +static sandbox_cfg_t* +sandbox_init_filter(void) +{ + sandbox_cfg_t *cfg = sandbox_cfg_new(); + + sandbox_cfg_allow_openat_filename(&cfg, + get_datadir_fname("cached-status"), 1); + + sandbox_cfg_allow_open_filename_array(&cfg, + get_datadir_fname("cached-certs"), 1, + get_datadir_fname("cached-certs.tmp"), 1, + get_datadir_fname("cached-consensus"), 1, + get_datadir_fname("unverified-consensus"), 1, + get_datadir_fname("unverified-consensus.tmp"), 1, + get_datadir_fname("cached-microdesc-consensus"), 1, + get_datadir_fname("cached-microdesc-consensus.tmp"), 1, + get_datadir_fname("cached-microdescs"), 1, + get_datadir_fname("cached-microdescs.tmp"), 1, + get_datadir_fname("cached-microdescs.new"), 1, + get_datadir_fname("cached-microdescs.new.tmp"), 1, + get_datadir_fname("unverified-microdesc-consensus"), 1, + get_datadir_fname("cached-descriptors"), 1, + get_datadir_fname("cached-descriptors.new"), 1, + get_datadir_fname("cached-descriptors.tmp"), 1, + get_datadir_fname("cached-descriptors.new.tmp"), 1, + get_datadir_fname("cached-descriptors.tmp.tmp"), 1, + get_datadir_fname("cached-extrainfo"), 1, + get_datadir_fname("state.tmp"), 1, + get_datadir_fname("unparseable-desc.tmp"), 1, + get_datadir_fname("unparseable-desc"), 1, + "/dev/srandom", 0, + "/dev/urandom", 0, + "/dev/random", 0, + NULL, 0 + ); + + sandbox_cfg_allow_stat_filename_array(&cfg, + get_datadir_fname(NULL), 1, + get_datadir_fname("lock"), 1, + get_datadir_fname("state"), 1, + get_datadir_fname("router-stability"), 1, + get_datadir_fname("cached-extrainfo.new"), 1, + NULL, 0 + ); + + // orport + if (server_mode(get_options())) { + sandbox_cfg_allow_open_filename_array(&cfg, + get_datadir_fname2("keys", "secret_id_key"), 1, + get_datadir_fname2("keys", "secret_onion_key"), 1, + get_datadir_fname2("keys", "secret_onion_key_ntor"), 1, + get_datadir_fname2("keys", "secret_onion_key_ntor.tmp"), 1, + get_datadir_fname2("keys", "secret_id_key.old"), 1, + get_datadir_fname2("keys", "secret_onion_key.old"), 1, + get_datadir_fname2("keys", "secret_onion_key_ntor.old"), 1, + get_datadir_fname2("keys", "secret_onion_key.tmp"), 1, + get_datadir_fname2("keys", "secret_id_key.tmp"), 1, + get_datadir_fname("fingerprint"), 1, + get_datadir_fname("fingerprint.tmp"), 1, + get_datadir_fname("cached-consensus"), 1, + get_datadir_fname("cached-consensus.tmp"), 1, + "/etc/resolv.conf", 0, + NULL, 0 + ); + + sandbox_cfg_allow_stat_filename_array(&cfg, + get_datadir_fname("keys"), 1, + get_datadir_fname("stats/dirreq-stats"), 1, + NULL, 0 + ); + } + + sandbox_cfg_allow_execve(&cfg, "/usr/local/bin/tor"); + + init_addrinfo(); + + return cfg; +} + /** Main entry point for the Tor process. Called from main(). */ /* This function is distinct from main() only so we can link main.c into * the unittest binary without conflicting with the unittests' main. */ @@ -2723,10 +2812,18 @@ tor_main(int argc, char *argv[]) return -1; if (get_options()->Sandbox) { - if (tor_global_sandbox()) { + sandbox_cfg_t* cfg = sandbox_init_filter(); + + if (sandbox_init(cfg)) { log_err(LD_BUG,"Failed to create syscall sandbox filter"); return -1; } + + // registering libevent rng +#ifdef HAVE_EVUTIL_SECURE_RNG_SET_URANDOM_DEVICE_FILE + evutil_secure_rng_set_urandom_device_file( + (char*) sandbox_intern_string("/dev/urandom")); +#endif } switch (get_options()->command) { diff --git a/src/or/routerlist.c b/src/or/routerlist.c index 46da17e03..2b894277c 100644 --- a/src/or/routerlist.c +++ b/src/or/routerlist.c @@ -37,7 +37,7 @@ #include "routerlist.h" #include "routerparse.h" #include "routerset.h" - +#include "../common/sandbox.h" // #define DEBUG_ROUTERLIST /****************************************************************************/ |