chiark / gitweb /
hostnamectl: should the sanitized arch, not the native uname() one
[elogind.git] / src / core / execute.c
index 474a4af895e61b912bc58a7d0d52f7dd3bc800c2..f8b7521ff9ceb20b4a8f81b96036d40cb37c2e68 100644 (file)
@@ -38,8 +38,8 @@
 #include <linux/fs.h>
 #include <linux/oom.h>
 #include <sys/poll.h>
-#include <linux/seccomp-bpf.h>
 #include <glob.h>
+#include <sys/personality.h>
 #include <libgen.h>
 #undef basename
 
 #include <selinux/selinux.h>
 #endif
 
+#ifdef HAVE_SECCOMP
+#include <seccomp.h>
+#endif
+
 #include "execute.h"
 #include "strv.h"
 #include "macro.h"
 #include "utmp-wtmp.h"
 #include "def.h"
 #include "path-util.h"
-#include "syscall-list.h"
 #include "env-util.h"
 #include "fileio.h"
 #include "unit.h"
 #include "async.h"
+#include "selinux-util.h"
+#include "errno-list.h"
+
+#ifdef HAVE_SECCOMP
+#include "seccomp-util.h"
+#endif
 
 #define IDLE_TIMEOUT_USEC (5*USEC_PER_SEC)
 #define IDLE_TIMEOUT2_USEC (1*USEC_PER_SEC)
@@ -932,57 +941,58 @@ static void rename_process_from_path(const char *path) {
         rename_process(process_name);
 }
 
-static int apply_seccomp(uint32_t *syscall_filter) {
-        static const struct sock_filter header[] = {
-                VALIDATE_ARCHITECTURE,
-                EXAMINE_SYSCALL
-        };
-        static const struct sock_filter footer[] = {
-                _KILL_PROCESS
-        };
-
-        int i;
-        unsigned n;
-        struct sock_filter *f;
-        struct sock_fprog prog = {};
+#ifdef HAVE_SECCOMP
 
-        assert(syscall_filter);
+static int apply_seccomp(ExecContext *c) {
+        uint32_t negative_action, action;
+        scmp_filter_ctx *seccomp;
+        Iterator i;
+        void *id;
+        int r;
 
-        /* First: count the syscalls to check for */
-        for (i = 0, n = 0; i < syscall_max(); i++)
-                if (syscall_filter[i >> 4] & (1 << (i & 31)))
-                        n++;
+        assert(c);
 
-        /* Second: build the filter program from a header the syscall
-         * matches and the footer */
-        f = alloca(sizeof(struct sock_filter) * (ELEMENTSOF(header) + 2*n + ELEMENTSOF(footer)));
-        memcpy(f, header, sizeof(header));
+        negative_action = c->syscall_errno == 0 ? SCMP_ACT_KILL : SCMP_ACT_ERRNO(c->syscall_errno);
 
-        for (i = 0, n = 0; i < syscall_max(); i++)
-                if (syscall_filter[i >> 4] & (1 << (i & 31))) {
-                        struct sock_filter item[] = {
-                                BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, INDEX_TO_SYSCALL(i), 0, 1),
-                                BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW)
-                        };
+        seccomp = seccomp_init(c->syscall_whitelist ? negative_action : SCMP_ACT_ALLOW);
+        if (!seccomp)
+                return -ENOMEM;
 
-                        assert_cc(ELEMENTSOF(item) == 2);
+        if (c->syscall_archs) {
 
-                        f[ELEMENTSOF(header) + 2*n]  = item[0];
-                        f[ELEMENTSOF(header) + 2*n+1] = item[1];
+                SET_FOREACH(id, c->syscall_archs, i) {
+                        r = seccomp_arch_add(seccomp, PTR_TO_UINT32(id) - 1);
+                        if (r == -EEXIST)
+                                continue;
+                        if (r < 0) {
+                                seccomp_release(seccomp);
+                                return r;
+                        }
+                }
+        } else {
 
-                        n++;
+                r = seccomp_add_secondary_archs(seccomp);
+                if (r < 0) {
+                        seccomp_release(seccomp);
+                        return r;
                 }
+        }
 
-        memcpy(f + (ELEMENTSOF(header) + 2*n), footer, sizeof(footer));
+        action = c->syscall_whitelist ? SCMP_ACT_ALLOW : negative_action;
+        SET_FOREACH(id, c->syscall_filter, i) {
+                r = seccomp_rule_add(seccomp, action, PTR_TO_INT(id) - 1, 0);
+                if (r < 0) {
+                        seccomp_release(seccomp);
+                        return r;
+                }
+        }
 
-        /* Third: install the filter */
-        prog.len = ELEMENTSOF(header) + ELEMENTSOF(footer) + 2*n;
-        prog.filter = f;
-        if (prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog) < 0)
-                return -errno;
+        r = seccomp_load(seccomp);
+        seccomp_release(seccomp);
 
-        return 0;
+        return r;
 }
+#endif
 
 static void do_idle_pipe_dance(int idle_pipe[4]) {
         assert(idle_pipe);
@@ -1363,6 +1373,13 @@ int exec_spawn(ExecCommand *command,
                                 goto fail_child;
                         }
 
+                if (context->personality != 0xffffffffUL)
+                        if (personality(context->personality) < 0) {
+                                err = -errno;
+                                r = EXIT_PERSONALITY;
+                                goto fail_child;
+                        }
+
                 if (context->utmp_id)
                         utmp_put_init_process(context->utmp_id, getpid(), getsid(0), context->tty_path);
 
@@ -1561,22 +1578,20 @@ int exec_spawn(ExecCommand *command,
                                         goto fail_child;
                                 }
 
-                        if (context->syscall_filter) {
-                                err = apply_seccomp(context->syscall_filter);
+#ifdef HAVE_SECCOMP
+                        if (context->syscall_filter || context->syscall_archs) {
+                                err = apply_seccomp(context);
                                 if (err < 0) {
                                         r = EXIT_SECCOMP;
                                         goto fail_child;
                                 }
                         }
+#endif
+
 #ifdef HAVE_SELINUX
                         if (context->selinux_context && use_selinux()) {
-                                err = security_check_context(context->selinux_context);
-                                if (err < 0) {
-                                        r = EXIT_SELINUX_CONTEXT;
-                                        goto fail_child;
-                                }
                                 err = setexeccon(context->selinux_context);
-                                if (err < 0) {
+                                if (err < 0 && !context->selinux_context_ignore) {
                                         r = EXIT_SELINUX_CONTEXT;
                                         goto fail_child;
                                 }
@@ -1676,6 +1691,7 @@ void exec_context_init(ExecContext *c) {
         c->syslog_level_prefix = true;
         c->ignore_sigpipe = true;
         c->timer_slack_nsec = (nsec_t) -1;
+        c->personality = 0xffffffffUL;
 }
 
 void exec_context_done(ExecContext *c) {
@@ -1743,8 +1759,13 @@ void exec_context_done(ExecContext *c) {
         free(c->selinux_context);
         c->selinux_context = NULL;
 
-        free(c->syscall_filter);
+#ifdef HAVE_SECCOMP
+        set_free(c->syscall_filter);
         c->syscall_filter = NULL;
+
+        set_free(c->syscall_archs);
+        c->syscall_archs = NULL;
+#endif
 }
 
 void exec_command_done(ExecCommand *c) {
@@ -1956,27 +1977,20 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
                         fprintf(f, "%s%s: %llu\n", prefix, rlimit_to_string(i), (unsigned long long) c->rlimit[i]->rlim_max);
 
         if (c->ioprio_set) {
-                char *class_str;
-                int r;
+                _cleanup_free_ char *class_str = NULL;
 
-                r = ioprio_class_to_string_alloc(IOPRIO_PRIO_CLASS(c->ioprio), &class_str);
-                if (r < 0)
-                        class_str = NULL;
+                ioprio_class_to_string_alloc(IOPRIO_PRIO_CLASS(c->ioprio), &class_str);
                 fprintf(f,
                         "%sIOSchedulingClass: %s\n"
                         "%sIOPriority: %i\n",
                         prefix, strna(class_str),
                         prefix, (int) IOPRIO_PRIO_DATA(c->ioprio));
-                free(class_str);
         }
 
         if (c->cpu_sched_set) {
-                char *policy_str;
-                int r;
+                _cleanup_free_ char *policy_str = NULL;
 
-                r = sched_policy_to_string_alloc(c->cpu_sched_policy, &policy_str);
-                if (r < 0)
-                        policy_str = NULL;
+                sched_policy_to_string_alloc(c->cpu_sched_policy, &policy_str);
                 fprintf(f,
                         "%sCPUSchedulingPolicy: %s\n"
                         "%sCPUSchedulingPriority: %i\n"
@@ -1984,7 +1998,6 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
                         prefix, strna(policy_str),
                         prefix, c->cpu_sched_priority,
                         prefix, yes_no(c->cpu_sched_reset_on_fork));
-                free(policy_str);
         }
 
         if (c->cpuset) {
@@ -2115,9 +2128,66 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
 
         if (c->selinux_context)
                 fprintf(f,
-                        "%sSELinuxContext: %s\n",
-                        prefix, c->selinux_context);
+                        "%sSELinuxContext: %s%s\n",
+                        prefix, c->selinux_context_ignore ? "-" : "", c->selinux_context);
+
+        if (c->personality != 0xffffffffUL)
+                fprintf(f,
+                        "%sPersonality: %s\n",
+                        prefix, strna(personality_to_string(c->personality)));
+
+        if (c->syscall_filter) {
+#ifdef HAVE_SECCOMP
+                Iterator j;
+                void *id;
+                bool first = true;
+#endif
+
+                fprintf(f,
+                        "%sSystemCallFilter: ",
+                        prefix);
 
+                if (!c->syscall_whitelist)
+                        fputc('~', f);
+
+#ifdef HAVE_SECCOMP
+                SET_FOREACH(id, c->syscall_filter, j) {
+                        _cleanup_free_ char *name = NULL;
+
+                        if (first)
+                                first = false;
+                        else
+                                fputc(' ', f);
+
+                        name = seccomp_syscall_resolve_num_arch(SCMP_ARCH_NATIVE, PTR_TO_INT(id) - 1);
+                        fputs(strna(name), f);
+                }
+#endif
+
+                fputc('\n', f);
+        }
+
+        if (c->syscall_archs) {
+#ifdef HAVE_SECCOMP
+                Iterator j;
+                void *id;
+#endif
+
+                fprintf(f,
+                        "%sSystemCallArchitectures:",
+                        prefix);
+
+#ifdef HAVE_SECCOMP
+                SET_FOREACH(id, c->syscall_archs, j)
+                        fprintf(f, " %s", strna(seccomp_arch_to_string(PTR_TO_UINT32(id) - 1)));
+#endif
+                fputc('\n', f);
+        }
+
+        if (c->syscall_errno != 0)
+                fprintf(f,
+                        "%sSystemCallErrorNumber: %s\n",
+                        prefix, strna(errno_to_name(c->syscall_errno)));
 }
 
 void exec_status_start(ExecStatus *s, pid_t pid) {