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Diffstat (limited to 'src/core/execute.c')
-rw-r--r--src/core/execute.c392
1 files changed, 315 insertions, 77 deletions
diff --git a/src/core/execute.c b/src/core/execute.c
index 2026137721..3da7ef3be6 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -837,6 +837,8 @@ static int null_conv(
return PAM_CONV_ERR;
}
+#endif
+
static int setup_pam(
const char *name,
const char *user,
@@ -845,6 +847,8 @@ static int setup_pam(
char ***env,
int fds[], unsigned n_fds) {
+#ifdef HAVE_PAM
+
static const struct pam_conv conv = {
.conv = null_conv,
.appdata_ptr = NULL
@@ -1038,8 +1042,10 @@ fail:
closelog();
return r;
-}
+#else
+ return 0;
#endif
+}
static void rename_process_from_path(const char *path) {
char process_name[11];
@@ -1273,6 +1279,10 @@ static int apply_memory_deny_write_execute(const Unit* u, const ExecContext *c)
if (!seccomp)
return -ENOMEM;
+ r = seccomp_add_secondary_archs(seccomp);
+ if (r < 0)
+ goto finish;
+
r = seccomp_rule_add(
seccomp,
SCMP_ACT_ERRNO(EPERM),
@@ -1322,6 +1332,10 @@ static int apply_restrict_realtime(const Unit* u, const ExecContext *c) {
if (!seccomp)
return -ENOMEM;
+ r = seccomp_add_secondary_archs(seccomp);
+ if (r < 0)
+ goto finish;
+
/* Determine the highest policy constant we want to allow */
for (i = 0; i < ELEMENTSOF(permitted_policies); i++)
if (permitted_policies[i] > max_policy)
@@ -1375,12 +1389,121 @@ finish:
return r;
}
+static int apply_protect_sysctl(Unit *u, const ExecContext *c) {
+ scmp_filter_ctx *seccomp;
+ int r;
+
+ assert(c);
+
+ /* Turn off the legacy sysctl() system call. Many distributions turn this off while building the kernel, but
+ * let's protect even those systems where this is left on in the kernel. */
+
+ if (skip_seccomp_unavailable(u, "ProtectKernelTunables="))
+ return 0;
+
+ seccomp = seccomp_init(SCMP_ACT_ALLOW);
+ if (!seccomp)
+ return -ENOMEM;
+
+ r = seccomp_add_secondary_archs(seccomp);
+ if (r < 0)
+ goto finish;
+
+ r = seccomp_rule_add(
+ seccomp,
+ SCMP_ACT_ERRNO(EPERM),
+ SCMP_SYS(_sysctl),
+ 0);
+ if (r < 0)
+ goto finish;
+
+ r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_NNP, 0);
+ if (r < 0)
+ goto finish;
+
+ r = seccomp_load(seccomp);
+
+finish:
+ seccomp_release(seccomp);
+ return r;
+}
+
+static int apply_private_devices(Unit *u, const ExecContext *c) {
+ const SystemCallFilterSet *set;
+ scmp_filter_ctx *seccomp;
+ const char *sys;
+ bool syscalls_found = false;
+ int r;
+
+ assert(c);
+
+ /* If PrivateDevices= is set, also turn off iopl and all @raw-io syscalls. */
+
+ if (skip_seccomp_unavailable(u, "PrivateDevices="))
+ return 0;
+
+ seccomp = seccomp_init(SCMP_ACT_ALLOW);
+ if (!seccomp)
+ return -ENOMEM;
+
+ r = seccomp_add_secondary_archs(seccomp);
+ if (r < 0)
+ goto finish;
+
+ for (set = syscall_filter_sets; set->set_name; set++)
+ if (streq(set->set_name, "@raw-io")) {
+ syscalls_found = true;
+ break;
+ }
+
+ /* We should never fail here */
+ if (!syscalls_found) {
+ r = -EOPNOTSUPP;
+ goto finish;
+ }
+
+ NULSTR_FOREACH(sys, set->value) {
+ int id;
+ bool add = true;
+
+#ifndef __NR_s390_pci_mmio_read
+ if (streq(sys, "s390_pci_mmio_read"))
+ add = false;
+#endif
+#ifndef __NR_s390_pci_mmio_write
+ if (streq(sys, "s390_pci_mmio_write"))
+ add = false;
+#endif
+
+ if (!add)
+ continue;
+
+ id = seccomp_syscall_resolve_name(sys);
+
+ r = seccomp_rule_add(
+ seccomp,
+ SCMP_ACT_ERRNO(EPERM),
+ id, 0);
+ if (r < 0)
+ goto finish;
+ }
+
+ r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_NNP, 0);
+ if (r < 0)
+ goto finish;
+
+ r = seccomp_load(seccomp);
+
+finish:
+ seccomp_release(seccomp);
+ return r;
+}
+
#endif
static void do_idle_pipe_dance(int idle_pipe[4]) {
assert(idle_pipe);
-
idle_pipe[1] = safe_close(idle_pipe[1]);
idle_pipe[2] = safe_close(idle_pipe[2]);
@@ -1581,7 +1704,9 @@ static bool exec_needs_mount_namespace(
if (context->private_devices ||
context->protect_system != PROTECT_SYSTEM_NO ||
- context->protect_home != PROTECT_HOME_NO)
+ context->protect_home != PROTECT_HOME_NO ||
+ context->protect_kernel_tunables ||
+ context->protect_control_groups)
return true;
return false;
@@ -1740,6 +1865,111 @@ static int setup_private_users(uid_t uid, gid_t gid) {
return 0;
}
+static int setup_runtime_directory(
+ const ExecContext *context,
+ const ExecParameters *params,
+ uid_t uid,
+ gid_t gid) {
+
+ char **rt;
+ int r;
+
+ assert(context);
+ assert(params);
+
+ STRV_FOREACH(rt, context->runtime_directory) {
+ _cleanup_free_ char *p;
+
+ p = strjoin(params->runtime_prefix, "/", *rt, NULL);
+ if (!p)
+ return -ENOMEM;
+
+ r = mkdir_p_label(p, context->runtime_directory_mode);
+ if (r < 0)
+ return r;
+
+ r = chmod_and_chown(p, context->runtime_directory_mode, uid, gid);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+static int setup_smack(
+ const ExecContext *context,
+ const ExecCommand *command) {
+
+#ifdef HAVE_SMACK
+ int r;
+
+ assert(context);
+ assert(command);
+
+ if (!mac_smack_use())
+ return 0;
+
+ if (context->smack_process_label) {
+ r = mac_smack_apply_pid(0, context->smack_process_label);
+ if (r < 0)
+ return r;
+ }
+#ifdef SMACK_DEFAULT_PROCESS_LABEL
+ else {
+ _cleanup_free_ char *exec_label = NULL;
+
+ r = mac_smack_read(command->path, SMACK_ATTR_EXEC, &exec_label);
+ if (r < 0 && r != -ENODATA && r != -EOPNOTSUPP)
+ return r;
+
+ r = mac_smack_apply_pid(0, exec_label ? : SMACK_DEFAULT_PROCESS_LABEL);
+ if (r < 0)
+ return r;
+ }
+#endif
+#endif
+
+ return 0;
+}
+
+static int compile_read_write_paths(
+ const ExecContext *context,
+ const ExecParameters *params,
+ char ***ret) {
+
+ _cleanup_strv_free_ char **l = NULL;
+ char **rt;
+
+ /* Compile the list of writable paths. This is the combination of the explicitly configured paths, plus all
+ * runtime directories. */
+
+ if (strv_isempty(context->read_write_paths) &&
+ strv_isempty(context->runtime_directory)) {
+ *ret = NULL; /* NOP if neither is set */
+ return 0;
+ }
+
+ l = strv_copy(context->read_write_paths);
+ if (!l)
+ return -ENOMEM;
+
+ STRV_FOREACH(rt, context->runtime_directory) {
+ char *s;
+
+ s = strjoin(params->runtime_prefix, "/", *rt, NULL);
+ if (!s)
+ return -ENOMEM;
+
+ if (strv_consume(&l, s) < 0)
+ return -ENOMEM;
+ }
+
+ *ret = l;
+ l = NULL;
+
+ return 0;
+}
+
static void append_socket_pair(int *array, unsigned *n, int pair[2]) {
assert(array);
assert(n);
@@ -1796,6 +2026,37 @@ static int close_remaining_fds(
return close_all_fds(dont_close, n_dont_close);
}
+static bool context_has_address_families(const ExecContext *c) {
+ assert(c);
+
+ return c->address_families_whitelist ||
+ !set_isempty(c->address_families);
+}
+
+static bool context_has_syscall_filters(const ExecContext *c) {
+ assert(c);
+
+ return c->syscall_whitelist ||
+ !set_isempty(c->syscall_filter) ||
+ !set_isempty(c->syscall_archs);
+}
+
+static bool context_has_no_new_privileges(const ExecContext *c) {
+ assert(c);
+
+ if (c->no_new_privileges)
+ return true;
+
+ if (have_effective_cap(CAP_SYS_ADMIN)) /* if we are privileged, we don't need NNP */
+ return false;
+
+ return context_has_address_families(c) || /* we need NNP if we have any form of seccomp and are unprivileged */
+ c->memory_deny_write_execute ||
+ c->restrict_realtime ||
+ c->protect_kernel_tunables ||
+ context_has_syscall_filters(c);
+}
+
static int send_user_lookup(
Unit *unit,
int user_lookup_fd,
@@ -1940,22 +2201,14 @@ static int exec_child(
} else {
if (context->user) {
username = context->user;
- r = get_user_creds(&username, &uid, &gid, &home, &shell);
+ r = get_user_creds_clean(&username, &uid, &gid, &home, &shell);
if (r < 0) {
*exit_status = EXIT_USER;
return r;
}
- /* Don't set $HOME or $SHELL if they are are not particularly enlightening anyway. */
- if (isempty(home) || path_equal(home, "/"))
- home = NULL;
-
- if (isempty(shell) || PATH_IN_SET(shell,
- "/bin/nologin",
- "/sbin/nologin",
- "/usr/bin/nologin",
- "/usr/sbin/nologin"))
- shell = NULL;
+ /* Note that we don't set $HOME or $SHELL if they are are not particularly enlightening anyway
+ * (i.e. are "/" or "/bin/nologin"). */
}
if (context->group) {
@@ -2108,28 +2361,10 @@ static int exec_child(
}
if (!strv_isempty(context->runtime_directory) && params->runtime_prefix) {
- char **rt;
-
- STRV_FOREACH(rt, context->runtime_directory) {
- _cleanup_free_ char *p;
-
- p = strjoin(params->runtime_prefix, "/", *rt, NULL);
- if (!p) {
- *exit_status = EXIT_RUNTIME_DIRECTORY;
- return -ENOMEM;
- }
-
- r = mkdir_p_label(p, context->runtime_directory_mode);
- if (r < 0) {
- *exit_status = EXIT_RUNTIME_DIRECTORY;
- return r;
- }
-
- r = chmod_and_chown(p, context->runtime_directory_mode, uid, gid);
- if (r < 0) {
- *exit_status = EXIT_RUNTIME_DIRECTORY;
- return r;
- }
+ r = setup_runtime_directory(context, params, uid, gid);
+ if (r < 0) {
+ *exit_status = EXIT_RUNTIME_DIRECTORY;
+ return r;
}
}
@@ -2168,41 +2403,15 @@ static int exec_child(
}
accum_env = strv_env_clean(accum_env);
- umask(context->umask);
+ (void) umask(context->umask);
if ((params->flags & EXEC_APPLY_PERMISSIONS) && !command->privileged) {
- r = enforce_groups(context, username, gid);
+ r = setup_smack(context, command);
if (r < 0) {
- *exit_status = EXIT_GROUP;
+ *exit_status = EXIT_SMACK_PROCESS_LABEL;
return r;
}
-#ifdef HAVE_SMACK
- if (context->smack_process_label) {
- r = mac_smack_apply_pid(0, context->smack_process_label);
- if (r < 0) {
- *exit_status = EXIT_SMACK_PROCESS_LABEL;
- return r;
- }
- }
-#ifdef SMACK_DEFAULT_PROCESS_LABEL
- else {
- _cleanup_free_ char *exec_label = NULL;
- r = mac_smack_read(command->path, SMACK_ATTR_EXEC, &exec_label);
- if (r < 0 && r != -ENODATA && r != -EOPNOTSUPP) {
- *exit_status = EXIT_SMACK_PROCESS_LABEL;
- return r;
- }
-
- r = mac_smack_apply_pid(0, exec_label ? : SMACK_DEFAULT_PROCESS_LABEL);
- if (r < 0) {
- *exit_status = EXIT_SMACK_PROCESS_LABEL;
- return r;
- }
- }
-#endif
-#endif
-#ifdef HAVE_PAM
if (context->pam_name && username) {
r = setup_pam(context->pam_name, username, uid, context->tty_path, &accum_env, fds, n_fds);
if (r < 0) {
@@ -2210,7 +2419,6 @@ static int exec_child(
return r;
}
}
-#endif
}
if (context->private_network && runtime && runtime->netns_storage_socket[0] >= 0) {
@@ -2222,8 +2430,8 @@ static int exec_child(
}
needs_mount_namespace = exec_needs_mount_namespace(context, params, runtime);
-
if (needs_mount_namespace) {
+ _cleanup_free_ char **rw = NULL;
char *tmp = NULL, *var = NULL;
/* The runtime struct only contains the parent
@@ -2239,14 +2447,22 @@ static int exec_child(
var = strjoina(runtime->var_tmp_dir, "/tmp");
}
+ r = compile_read_write_paths(context, params, &rw);
+ if (r < 0) {
+ *exit_status = EXIT_NAMESPACE;
+ return r;
+ }
+
r = setup_namespace(
(params->flags & EXEC_APPLY_CHROOT) ? context->root_directory : NULL,
- context->read_write_paths,
+ rw,
context->read_only_paths,
context->inaccessible_paths,
tmp,
var,
context->private_devices,
+ context->protect_kernel_tunables,
+ context->protect_control_groups,
context->protect_home,
context->protect_system,
context->mount_flags);
@@ -2264,6 +2480,14 @@ static int exec_child(
}
}
+ if ((params->flags & EXEC_APPLY_PERMISSIONS) && !command->privileged) {
+ r = enforce_groups(context, username, gid);
+ if (r < 0) {
+ *exit_status = EXIT_GROUP;
+ return r;
+ }
+ }
+
if (context->working_directory_home)
wd = home;
else if (context->working_directory)
@@ -2335,11 +2559,6 @@ static int exec_child(
if ((params->flags & EXEC_APPLY_PERMISSIONS) && !command->privileged) {
- bool use_address_families = context->address_families_whitelist ||
- !set_isempty(context->address_families);
- bool use_syscall_filter = context->syscall_whitelist ||
- !set_isempty(context->syscall_filter) ||
- !set_isempty(context->syscall_archs);
int secure_bits = context->secure_bits;
for (i = 0; i < _RLIMIT_MAX; i++) {
@@ -2416,15 +2635,14 @@ static int exec_child(
return -errno;
}
- if (context->no_new_privileges ||
- (!have_effective_cap(CAP_SYS_ADMIN) && (use_address_families || context->memory_deny_write_execute || context->restrict_realtime || use_syscall_filter)))
+ if (context_has_no_new_privileges(context))
if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) < 0) {
*exit_status = EXIT_NO_NEW_PRIVILEGES;
return -errno;
}
#ifdef HAVE_SECCOMP
- if (use_address_families) {
+ if (context_has_address_families(context)) {
r = apply_address_families(unit, context);
if (r < 0) {
*exit_status = EXIT_ADDRESS_FAMILIES;
@@ -2448,7 +2666,23 @@ static int exec_child(
}
}
- if (use_syscall_filter) {
+ if (context->protect_kernel_tunables) {
+ r = apply_protect_sysctl(unit, context);
+ if (r < 0) {
+ *exit_status = EXIT_SECCOMP;
+ return r;
+ }
+ }
+
+ if (context->private_devices) {
+ r = apply_private_devices(unit, context);
+ if (r < 0) {
+ *exit_status = EXIT_SECCOMP;
+ return r;
+ }
+ }
+
+ if (context_has_syscall_filters(context)) {
r = apply_seccomp(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
@@ -2880,6 +3114,8 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
"%sNonBlocking: %s\n"
"%sPrivateTmp: %s\n"
"%sPrivateDevices: %s\n"
+ "%sProtectKernelTunables: %s\n"
+ "%sProtectControlGroups: %s\n"
"%sPrivateNetwork: %s\n"
"%sPrivateUsers: %s\n"
"%sProtectHome: %s\n"
@@ -2893,6 +3129,8 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
prefix, yes_no(c->non_blocking),
prefix, yes_no(c->private_tmp),
prefix, yes_no(c->private_devices),
+ prefix, yes_no(c->protect_kernel_tunables),
+ prefix, yes_no(c->protect_control_groups),
prefix, yes_no(c->private_network),
prefix, yes_no(c->private_users),
prefix, protect_home_to_string(c->protect_home),
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-07-03 15:43:19 +0000