SymbX/systemd
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

exec: SystemCallLog= directive

Browse Source 
With new directive SystemCallLog= it's possible to list system calls to be
logged. This can be used for auditing or temporarily when constructing system
call filters.

---
v5: drop intermediary, update HASHMAP_FOREACH_KEY() use
v4: skip useless debug messages, actually parse directive
v3: don't declare unused variables with old libseccomp
v2: fix build without seccomp or old libseccomp
This commit is contained in:
Topi Miettinen
2020-09-15 12:54:17 +03:00
parent 005bfaf118
commit 9df2cdd8ec
11 changed files with 280 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/core/dbus-execute.c
+123
View File
@@ -415,6 +415,58 @@ static int property_get_syscall_filter(
return sd_bus_message_close_container(reply);
}
static int property_get_syscall_log(
sd_bus *bus,
const char *path,
const char *interface,
const char *property,
sd_bus_message *reply,
void *userdata,
sd_bus_error *error) {
ExecContext *c = userdata;
_cleanup_strv_free_ char **l = NULL;
int r;
#if HAVE_SECCOMP
void *id, *val;
#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_log_allow_list);
if (r < 0)
return r;
#if HAVE_SECCOMP
HASHMAP_FOREACH_KEY(val, id, c->syscall_log) {
char *name = NULL;
name = seccomp_syscall_resolve_num_arch(SCMP_ARCH_NATIVE, PTR_TO_INT(id) - 1);
if (!name)
continue;
r = strv_consume(&l, name);
if (r < 0)
return r;
}
#endif
strv_sort(l);
r = sd_bus_message_append_strv(reply, l);
if (r < 0)
return r;
return sd_bus_message_close_container(reply);
}
static int property_get_syscall_archs(
sd_bus *bus,
const char *path,
@@ -1068,6 +1120,7 @@ const sd_bus_vtable bus_exec_vtable[] = {
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", bus_property_get_int, offsetof(ExecContext, syscall_errno), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("SystemCallLog", "(bas)", property_get_syscall_log, 0, SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("Personality", "s", property_get_personality, offsetof(ExecContext, personality), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("LockPersonality", "b", bus_property_get_bool, offsetof(ExecContext, lock_personality), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("RestrictAddressFamilies", "(bas)", property_get_address_families, 0, SD_BUS_VTABLE_PROPERTY_CONST),
@@ -2230,6 +2283,76 @@ int bus_exec_context_set_transient_property(
return 1;
} else if (streq(name, "SystemCallLog")) {
int allow_list;
_cleanup_strv_free_ char **l = NULL;
r = sd_bus_message_enter_container(message, 'r', "bas");
if (r < 0)
return r;
r = sd_bus_message_read(message, "b", &allow_list);
if (r < 0)
return r;
r = sd_bus_message_read_strv(message, &l);
if (r < 0)
return r;
r = sd_bus_message_exit_container(message);
if (r < 0)
return r;
if (!UNIT_WRITE_FLAGS_NOOP(flags)) {
_cleanup_free_ char *joined = NULL;
SeccompParseFlags invert_flag = allow_list ? 0 : SECCOMP_PARSE_INVERT;
char **s;
if (strv_isempty(l)) {
c->syscall_log_allow_list = false;
c->syscall_log = hashmap_free(c->syscall_log);
unit_write_settingf(u, flags, name, "SystemCallLog=");
return 1;
}
if (!c->syscall_log) {
c->syscall_log = hashmap_new(NULL);
if (!c->syscall_log)
return log_oom();
c->syscall_log_allow_list = allow_list;
}
STRV_FOREACH(s, l) {
_cleanup_free_ char *n = NULL;
int e;
r = parse_syscall_and_errno(*s, &n, &e);
if (r < 0)
return r;
r = seccomp_parse_syscall_filter(n,
0, /* errno not used */
c->syscall_log,
SECCOMP_PARSE_LOG | SECCOMP_PARSE_PERMISSIVE |
invert_flag |
(c->syscall_log_allow_list ? SECCOMP_PARSE_ALLOW_LIST : 0),
u->id,
NULL, 0);
if (r < 0)
return r;
}
joined = strv_join(l, " ");
if (!joined)
return -ENOMEM;
unit_write_settingf(u, flags, name, "SystemCallLog=%s%s", allow_list ? "" : "~", joined);
}
return 1;
} else if (streq(name, "SystemCallArchitectures")) {
_cleanup_strv_free_ char **l = NULL;