chiark / gitweb /
execute: support syscall filtering using seccomp filters
[elogind.git] / src / core / load-fragment.c
index 1ca0dece678fed2a7a30b170fca48516f5e9fa31..7fcd63a17a69b3d05124cf712a526f48225d1689 100644 (file)
@@ -45,6 +45,7 @@
 #include "bus-errors.h"
 #include "utf8.h"
 #include "path-util.h"
+#include "syscall-list.h"
 
 #ifndef HAVE_SYSV_COMPAT
 int config_parse_warn_compat(
@@ -879,7 +880,7 @@ int config_parse_bounding_set(
 
                 if (r < 0) {
                         log_error("[%s:%u] Failed to parse capability bounding set, ignoring: %s", filename, line, rvalue);
-                        return 0;
+                        continue;
                 }
 
                 sum |= ((uint64_t) 1ULL) << (uint64_t) cap;
@@ -1910,7 +1911,7 @@ int config_parse_unit_blkio_bandwidth(const char *filename, unsigned line, const
         }
 
         if (parse_bytes(l[1], &bytes) < 0 || bytes <= 0) {
-                log_error("[%s:%u] Failed to parse block IO bandwith value, ignoring: %s", filename, line, rvalue);
+                log_error("[%s:%u] Failed to parse block IO bandwidth value, ignoring: %s", filename, line, rvalue);
                 strv_free(l);
                 return 0;
         }
@@ -2001,6 +2002,88 @@ int config_parse_documentation(
         return r;
 }
 
+static void syscall_set(uint32_t *p, int nr) {
+        p[nr >> 4] |= 1 << (nr & 31);
+}
+
+static void syscall_unset(uint32_t *p, int nr) {
+        p[nr >> 4] &= ~(1 << (nr & 31));
+}
+
+int config_parse_syscall_filter(
+                const char *filename,
+                unsigned line,
+                const char *section,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        ExecContext *c = data;
+        Unit *u = userdata;
+        bool invert;
+        char *w;
+        size_t l;
+        char *state;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(u);
+
+        if (rvalue[0] == '~') {
+                invert = true;
+                rvalue++;
+        }
+
+        if (!c->syscall_filter) {
+                size_t n;
+
+                n = (syscall_max() + 31) >> 4;
+                c->syscall_filter = new(uint32_t, n);
+                if (!c->syscall_filter)
+                        return -ENOMEM;
+
+                memset(c->syscall_filter, invert ? 0xFF : 0, n * sizeof(uint32_t));
+
+                /* Add these by default */
+                syscall_set(c->syscall_filter, __NR_execve);
+                syscall_set(c->syscall_filter, __NR_rt_sigreturn);
+#ifdef __NR_sigreturn
+                syscall_set(c->syscall_filter, __NR_sigreturn);
+#endif
+                syscall_set(c->syscall_filter, __NR_exit_group);
+                syscall_set(c->syscall_filter, __NR_exit);
+        }
+
+        FOREACH_WORD_QUOTED(w, l, rvalue, state) {
+                int id;
+                char *t;
+
+                t = strndup(w, l);
+                if (!t)
+                        return -ENOMEM;
+
+                id = syscall_from_name(t);
+                free(t);
+
+                if (id < 0)  {
+                        log_error("[%s:%u] Failed to parse syscall, ignoring: %s", filename, line, rvalue);
+                        continue;
+                }
+
+                if (invert)
+                        syscall_unset(c->syscall_filter, id);
+                else
+                        syscall_set(c->syscall_filter, id);
+        }
+
+        c->no_new_privileges = true;
+
+        return 0;
+}
+
 #define FOLLOW_MAX 8
 
 static int open_follow(char **filename, FILE **_f, Set *names, char **_final) {
@@ -2047,21 +2130,24 @@ static int open_follow(char **filename, FILE **_f, Set *names, char **_final) {
                 }
 
                 /* Try to open the file name, but don't if its a symlink */
-                if ((fd = open(*filename, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW)) >= 0)
+                fd = open(*filename, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+                if (fd >= 0)
                         break;
 
                 if (errno != ELOOP)
                         return -errno;
 
                 /* Hmm, so this is a symlink. Let's read the name, and follow it manually */
-                if ((r = readlink_and_make_absolute(*filename, &target)) < 0)
+                r = readlink_and_make_absolute(*filename, &target);
+                if (r < 0)
                         return r;
 
                 free(*filename);
                 *filename = target;
         }
 
-        if (!(f = fdopen(fd, "re"))) {
+        f = fdopen(fd, "re");
+        if (!f) {
                 r = -errno;
                 close_nointr_nofail(fd);
                 return r;
@@ -2085,7 +2171,8 @@ static int merge_by_names(Unit **u, Set *names, const char *id) {
 
                 /* First try to merge in the other name into our
                  * unit */
-                if ((r = unit_merge_by_name(*u, k)) < 0) {
+                r = unit_merge_by_name(*u, k);
+                if (r < 0) {
                         Unit *other;
 
                         /* Hmm, we couldn't merge the other unit into
@@ -2095,11 +2182,13 @@ static int merge_by_names(Unit **u, Set *names, const char *id) {
                         other = manager_get_unit((*u)->manager, k);
                         free(k);
 
-                        if (other)
-                                if ((r = unit_merge(other, *u)) >= 0) {
+                        if (other) {
+                                r = unit_merge(other, *u);
+                                if (r >= 0) {
                                         *u = other;
                                         return merge_by_names(u, names, NULL);
                                 }
+                        }
 
                         return r;
                 }
@@ -2130,12 +2219,14 @@ static int load_from_path(Unit *u, const char *path) {
 
         if (path_is_absolute(path)) {
 
-                if (!(filename = strdup(path))) {
+                filename = strdup(path);
+                if (!filename) {
                         r = -ENOMEM;
                         goto finish;
                 }
 
-                if ((r = open_follow(&filename, &f, symlink_names, &id)) < 0) {
+                r = open_follow(&filename, &f, symlink_names, &id);
+                if (r < 0) {
                         free(filename);
                         filename = NULL;
 
@@ -2151,7 +2242,8 @@ static int load_from_path(Unit *u, const char *path) {
                         /* Instead of opening the path right away, we manually
                          * follow all symlinks and add their name to our unit
                          * name set while doing so */
-                        if (!(filename = path_make_absolute(path, *p))) {
+                        filename = path_make_absolute(path, *p);
+                        if (!filename) {
                                 r = -ENOMEM;
                                 goto finish;
                         }
@@ -2163,8 +2255,6 @@ static int load_from_path(Unit *u, const char *path) {
                                 r = open_follow(&filename, &f, symlink_names, &id);
 
                         if (r < 0) {
-                                char *sn;
-
                                 free(filename);
                                 filename = NULL;
 
@@ -2172,9 +2262,7 @@ static int load_from_path(Unit *u, const char *path) {
                                         goto finish;
 
                                 /* Empty the symlink names for the next run */
-                                while ((sn = set_steal_first(symlink_names)))
-                                        free(sn);
-
+                                set_clear_free(symlink_names);
                                 continue;
                         }
 
@@ -2189,7 +2277,8 @@ static int load_from_path(Unit *u, const char *path) {
         }
 
         merged = u;
-        if ((r = merge_by_names(&merged, symlink_names, id)) < 0)
+        r = merge_by_names(&merged, symlink_names, id);
+        if (r < 0)
                 goto finish;
 
         if (merged != u) {
@@ -2252,7 +2341,8 @@ int unit_load_fragment(Unit *u) {
         /* First, try to find the unit under its id. We always look
          * for unit files in the default directories, to make it easy
          * to override things by placing things in /etc/systemd/system */
-        if ((r = load_from_path(u, u->id)) < 0)
+        r = load_from_path(u, u->id);
+        if (r < 0)
                 return r;
 
         /* Try to find an alias we can load this with */
@@ -2262,7 +2352,8 @@ int unit_load_fragment(Unit *u) {
                         if (t == u->id)
                                 continue;
 
-                        if ((r = load_from_path(u, t)) < 0)
+                        r = load_from_path(u, t);
+                        if (r < 0)
                                 return r;
 
                         if (u->load_state != UNIT_STUB)
@@ -2272,7 +2363,8 @@ int unit_load_fragment(Unit *u) {
         /* And now, try looking for it under the suggested (originally linked) path */
         if (u->load_state == UNIT_STUB && u->fragment_path) {
 
-                if ((r = load_from_path(u, u->fragment_path)) < 0)
+                r = load_from_path(u, u->fragment_path);
+                if (r < 0)
                         return r;
 
                 if (u->load_state == UNIT_STUB) {
@@ -2288,7 +2380,8 @@ int unit_load_fragment(Unit *u) {
         if (u->load_state == UNIT_STUB && u->instance) {
                 char *k;
 
-                if (!(k = unit_name_template(u->id)))
+                k = unit_name_template(u->id);
+                if (!k)
                         return -ENOMEM;
 
                 r = load_from_path(u, k);
@@ -2303,7 +2396,8 @@ int unit_load_fragment(Unit *u) {
                                 if (t == u->id)
                                         continue;
 
-                                if (!(k = unit_name_template(t)))
+                                k = unit_name_template(t);
+                                if (!k)
                                         return -ENOMEM;
 
                                 r = load_from_path(u, k);