core: add SystemCallArchitectures= unit setting to allow disabling of non-native

architecture support for system calls

Also, turn system call filter bus properties into complex types instead
of concatenated strings.

6 files changed, 161 insertions, 18 deletions

diff --git a/src/core/dbus-execute.c b/src/core/dbus-execute.c
index 435c3d505f..a62f517dc6 100644
--- a/src/core/dbus-execute.c
+++ b/src/core/dbus-execute.c
@@ -21,6 +21,10 @@
 
 #include <sys/prctl.h>
 
+#ifdef HAVE_SECCOMP
+#include <seccomp.h>
+#endif
+
 #include "bus-util.h"
 #include "missing.h"
 #include "ioprio.h"
@@ -31,6 +35,10 @@
 #include "capability.h"
 #include "env-util.h"
 
+#ifdef HAVE_SECCOMP
+#include "seccomp-util.h"
+#endif
+
 BUS_DEFINE_PROPERTY_GET_ENUM(bus_property_get_exec_output, exec_output, ExecOutput);
 
 static BUS_DEFINE_PROPERTY_GET_ENUM(property_get_exec_input, exec_input, ExecInput);
@@ -349,17 +357,25 @@ static int property_get_syscall_filter(
 
         ExecContext *c = userdata;
         _cleanup_strv_free_ char **l = NULL;
-        _cleanup_free_ char *t = NULL;
+        int r;
+
 #ifdef HAVE_SECCOMP
         Iterator i;
         void *id;
-        int r;
 #endif
 
         assert(bus);
         assert(reply);
         assert(c);
 
+        r = sd_bus_message_open_container(reply, 'r', "bas");
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(reply, "b", c->syscall_whitelist);
+        if (r < 0)
+                return r;
+
 #ifdef HAVE_SECCOMP
         SET_FOREACH(id, c->syscall_filter, i) {
                 char *name;
@@ -378,22 +394,56 @@ static int property_get_syscall_filter(
 
         strv_sort(l);
 
-        t = strv_join(l, " ");
-        if (!t)
-                return -ENOMEM;
+        r = sd_bus_message_append_strv(reply, l);
+        if (r < 0)
+                return r;
 
-        if (!c->syscall_whitelist) {
-                char *d;
+        return sd_bus_message_close_container(reply);
+}
 
-                d = strappend("~", t);
-                if (!d)
-                        return -ENOMEM;
+static int property_get_syscall_archs(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                const char *property,
+                sd_bus_message *reply,
+                void *userdata,
+                sd_bus_error *error) {
 
-                free(t);
-                t = d;
+        ExecContext *c = userdata;
+        _cleanup_strv_free_ char **l = NULL;
+        int r;
+
+#ifdef HAVE_SECCOMP
+        Iterator i;
+        void *id;
+#endif
+
+        assert(bus);
+        assert(reply);
+        assert(c);
+
+#ifdef HAVE_SECCOMP
+        SET_FOREACH(id, c->syscall_archs, i) {
+                const char *name;
+
+                name = seccomp_arch_to_string(PTR_TO_UINT32(id) - 1);
+                if (!name)
+                        continue;
+
+                r = strv_extend(&l, name);
+                if (r < 0)
+                        return -ENOMEM;
         }
+#endif
 
-        return sd_bus_message_append(reply, "s", t);
+        strv_sort(l);
+
+        r = sd_bus_message_append_strv(reply, l);
+        if (r < 0)
+                return r;
+
+        return 0;
 }
 
 static int property_get_syscall_errno(
@@ -476,7 +526,8 @@ const sd_bus_vtable bus_exec_vtable[] = {
         SD_BUS_PROPERTY("SELinuxContext", "s", NULL, offsetof(ExecContext, selinux_context), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("IgnoreSIGPIPE", "b", bus_property_get_bool, offsetof(ExecContext, ignore_sigpipe), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("NoNewPrivileges", "b", bus_property_get_bool, offsetof(ExecContext, no_new_privileges), SD_BUS_VTABLE_PROPERTY_CONST),
-        SD_BUS_PROPERTY("SystemCallFilter", "s", property_get_syscall_filter, 0, SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("SystemCallFilter", "(bas)", property_get_syscall_filter, 0, SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("SystemCallArchitectures", "as", property_get_syscall_archs, 0, SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("SystemCallErrorNumber", "i", property_get_syscall_errno, 0, SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_VTABLE_END
 };
diff --git a/src/core/execute.c b/src/core/execute.c
index 4033470e5b..06ddd5c91c 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -77,6 +77,10 @@
 #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)
 
@@ -953,8 +957,17 @@ static int apply_seccomp(ExecContext *c) {
         if (!seccomp)
                 return -ENOMEM;
 
-        action = c->syscall_whitelist ? SCMP_ACT_ALLOW : negative_action;
+        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;
+                }
+        }
 
+        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) {
@@ -1548,7 +1561,7 @@ int exec_spawn(ExecCommand *command,
                                 }
 
 #ifdef HAVE_SECCOMP
-                        if (context->syscall_filter) {
+                        if (context->syscall_filter || context->syscall_archs) {
                                 err = apply_seccomp(context);
                                 if (err < 0) {
                                         r = EXIT_SECCOMP;
@@ -1740,6 +1753,9 @@ void exec_context_done(ExecContext *c) {
 #ifdef HAVE_SECCOMP
         set_free(c->syscall_filter);
         c->syscall_filter = NULL;
+
+        set_free(c->syscall_archs);
+        c->syscall_archs = NULL;
 #endif
 }
 
@@ -2122,7 +2138,7 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
 #endif
 
                 fprintf(f,
-                        "%sSystemCallFilter: \n",
+                        "%sSystemCallFilter: ",
                         prefix);
 
                 if (!c->syscall_whitelist)
@@ -2137,7 +2153,7 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
                         else
                                 fputc(' ', f);
 
-                        name = seccomp_syscall_resolve_num_arch(PTR_TO_INT(id)-1, SCMP_ARCH_NATIVE);
+                        name = seccomp_syscall_resolve_num_arch(SCMP_ARCH_NATIVE, PTR_TO_INT(id) - 1);
                         fputs(strna(name), f);
                 }
 #endif
@@ -2145,6 +2161,23 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
                 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",
diff --git a/src/core/execute.h b/src/core/execute.h
index baf430a047..06b6b3fb2d 100644
--- a/src/core/execute.h
+++ b/src/core/execute.h
@@ -168,6 +168,7 @@ struct ExecContext {
         bool same_pgrp;
 
         Set *syscall_filter;
+        Set *syscall_archs;
         int syscall_errno;
         bool syscall_whitelist:1;
 
diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4
index 16c9e25785..fa559e58f9 100644
--- a/src/core/load-fragment-gperf.gperf.m4
+++ b/src/core/load-fragment-gperf.gperf.m4
@@ -51,8 +51,10 @@ $1.TimerSlackNSec,               config_parse_nsec,                  0,
 $1.NoNewPrivileges,              config_parse_bool,                  0,                             offsetof($1, exec_context.no_new_privileges)
 m4_ifdef(`HAVE_SECCOMP',
 `$1.SystemCallFilter,            config_parse_syscall_filter,        0,                             offsetof($1, exec_context)
+$1.SystemCallArchitectures,      config_parse_syscall_archs,         0,                             offsetof($1, exec_context)
 $1.SystemCallErrorNumber,        config_parse_syscall_errno,         0,                             offsetof($1, exec_context)',
 `$1.SystemCallFilter,            config_parse_warn_compat,           0,                             0
+$1.SystemCallArchitectures,      config_parse_warn_compat,           0,                             0
 $1.SystemCallErrorNumber,        config_parse_warn_compat,           0,                             0')
 $1.LimitCPU,                     config_parse_limit,                 RLIMIT_CPU,                    offsetof($1, exec_context.rlimit)
 $1.LimitFSIZE,                   config_parse_limit,                 RLIMIT_FSIZE,                  offsetof($1, exec_context.rlimit)
diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c
index 1b5856e273..ec04ad28ba 100644
--- a/src/core/load-fragment.c
+++ b/src/core/load-fragment.c
@@ -57,6 +57,10 @@
 #include "bus-error.h"
 #include "errno-list.h"
 
+#ifdef HAVE_SECCOMP
+#include "seccomp-util.h"
+#endif
+
 #if !defined(HAVE_SYSV_COMPAT) || !defined(HAVE_SECCOMP)
 int config_parse_warn_compat(
                 const char *unit,
@@ -2029,6 +2033,57 @@ int config_parse_syscall_filter(
         return 0;
 }
 
+int config_parse_syscall_archs(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        ExecContext *c = data;
+        char *w, *state;
+        size_t l;
+        int r;
+
+        if (isempty(rvalue)) {
+                set_free(c->syscall_archs);
+                c->syscall_archs = NULL;
+                return 0;
+        }
+
+        r = set_ensure_allocated(&c->syscall_archs, trivial_hash_func, trivial_compare_func);
+        if (r < 0)
+                return log_oom();
+
+        FOREACH_WORD_QUOTED(w, l, rvalue, state) {
+                _cleanup_free_ char *t = NULL;
+                uint32_t a;
+
+                t = strndup(w, l);
+                if (!t)
+                        return log_oom();
+
+                r = seccomp_arch_from_string(t, &a);
+                if (r < 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, EINVAL, "Failed to parse system call architecture, ignoring: %s", t);
+                        continue;
+                }
+
+                r = set_put(c->syscall_archs, UINT32_TO_PTR(a + 1));
+                if (r == -EEXIST)
+                        continue;
+                if (r < 0)
+                        return log_oom();
+        }
+
+        return 0;
+}
+
 int config_parse_syscall_errno(
                 const char *unit,
                 const char *filename,
diff --git a/src/core/load-fragment.h b/src/core/load-fragment.h
index 4cefa76157..23e9d1131b 100644
--- a/src/core/load-fragment.h
+++ b/src/core/load-fragment.h
@@ -74,6 +74,7 @@ int config_parse_notify_access(const char *unit, const char *filename, unsigned
 int config_parse_start_limit_action(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_unit_requires_mounts_for(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_syscall_filter(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
+int config_parse_syscall_archs(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_syscall_errno(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_environ(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_unit_slice(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);