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Diffstat (limited to 'src/core/execute.c')
-rw-r--r--src/core/execute.c1282
1 files changed, 999 insertions, 283 deletions
diff --git a/src/core/execute.c b/src/core/execute.c
index 7c178b97c3..85ee82c3e1 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -25,11 +25,14 @@
#include <signal.h>
#include <string.h>
#include <sys/capability.h>
+#include <sys/eventfd.h>
#include <sys/mman.h>
#include <sys/personality.h>
#include <sys/prctl.h>
+#include <sys/shm.h>
#include <sys/socket.h>
#include <sys/stat.h>
+#include <sys/types.h>
#include <sys/un.h>
#include <unistd.h>
#include <utmpx.h>
@@ -90,6 +93,7 @@
#include "selinux-util.h"
#include "signal-util.h"
#include "smack-util.h"
+#include "special.h"
#include "string-table.h"
#include "string-util.h"
#include "strv.h"
@@ -219,12 +223,36 @@ static void exec_context_tty_reset(const ExecContext *context, const ExecParamet
(void) vt_disallocate(path);
}
+static bool is_terminal_input(ExecInput i) {
+ return IN_SET(i,
+ EXEC_INPUT_TTY,
+ EXEC_INPUT_TTY_FORCE,
+ EXEC_INPUT_TTY_FAIL);
+}
+
static bool is_terminal_output(ExecOutput o) {
- return
- o == EXEC_OUTPUT_TTY ||
- o == EXEC_OUTPUT_SYSLOG_AND_CONSOLE ||
- o == EXEC_OUTPUT_KMSG_AND_CONSOLE ||
- o == EXEC_OUTPUT_JOURNAL_AND_CONSOLE;
+ return IN_SET(o,
+ EXEC_OUTPUT_TTY,
+ EXEC_OUTPUT_SYSLOG_AND_CONSOLE,
+ EXEC_OUTPUT_KMSG_AND_CONSOLE,
+ EXEC_OUTPUT_JOURNAL_AND_CONSOLE);
+}
+
+static bool exec_context_needs_term(const ExecContext *c) {
+ assert(c);
+
+ /* Return true if the execution context suggests we should set $TERM to something useful. */
+
+ if (is_terminal_input(c->std_input))
+ return true;
+
+ if (is_terminal_output(c->std_output))
+ return true;
+
+ if (is_terminal_output(c->std_error))
+ return true;
+
+ return !!c->tty_path;
}
static int open_null_as(int flags, int nfd) {
@@ -363,13 +391,6 @@ static int open_terminal_as(const char *path, mode_t mode, int nfd) {
return r;
}
-static bool is_terminal_input(ExecInput i) {
- return
- i == EXEC_INPUT_TTY ||
- i == EXEC_INPUT_TTY_FORCE ||
- i == EXEC_INPUT_TTY_FAIL;
-}
-
static int fixup_input(ExecInput std_input, int socket_fd, bool apply_tty_stdin) {
if (is_terminal_input(std_input) && !apply_tty_stdin)
@@ -392,7 +413,8 @@ static int fixup_output(ExecOutput std_output, int socket_fd) {
static int setup_input(
const ExecContext *context,
const ExecParameters *params,
- int socket_fd) {
+ int socket_fd,
+ int named_iofds[3]) {
ExecInput i;
@@ -410,7 +432,7 @@ static int setup_input(
return STDIN_FILENO;
}
- i = fixup_input(context->std_input, socket_fd, params->apply_tty_stdin);
+ i = fixup_input(context->std_input, socket_fd, params->flags & EXEC_APPLY_TTY_STDIN);
switch (i) {
@@ -442,6 +464,10 @@ static int setup_input(
case EXEC_INPUT_SOCKET:
return dup2(socket_fd, STDIN_FILENO) < 0 ? -errno : STDIN_FILENO;
+ case EXEC_INPUT_NAMED_FD:
+ (void) fd_nonblock(named_iofds[STDIN_FILENO], false);
+ return dup2(named_iofds[STDIN_FILENO], STDIN_FILENO) < 0 ? -errno : STDIN_FILENO;
+
default:
assert_not_reached("Unknown input type");
}
@@ -453,6 +479,7 @@ static int setup_output(
const ExecParameters *params,
int fileno,
int socket_fd,
+ int named_iofds[3],
const char *ident,
uid_t uid,
gid_t gid,
@@ -485,7 +512,7 @@ static int setup_output(
return STDERR_FILENO;
}
- i = fixup_input(context->std_input, socket_fd, params->apply_tty_stdin);
+ i = fixup_input(context->std_input, socket_fd, params->flags & EXEC_APPLY_TTY_STDIN);
o = fixup_output(context->std_output, socket_fd);
if (fileno == STDERR_FILENO) {
@@ -504,7 +531,7 @@ static int setup_output(
return fileno;
/* Duplicate from stdout if possible */
- if (e == o || e == EXEC_OUTPUT_INHERIT)
+ if ((e == o && e != EXEC_OUTPUT_NAMED_FD) || e == EXEC_OUTPUT_INHERIT)
return dup2(STDOUT_FILENO, fileno) < 0 ? -errno : fileno;
o = e;
@@ -566,6 +593,10 @@ static int setup_output(
assert(socket_fd >= 0);
return dup2(socket_fd, fileno) < 0 ? -errno : fileno;
+ case EXEC_OUTPUT_NAMED_FD:
+ (void) fd_nonblock(named_iofds[fileno], false);
+ return dup2(named_iofds[fileno], fileno) < 0 ? -errno : fileno;
+
default:
assert_not_reached("Unknown error type");
}
@@ -701,73 +732,157 @@ static int ask_for_confirmation(char *response, char **argv) {
return r;
}
-static int enforce_groups(const ExecContext *context, const char *username, gid_t gid) {
- bool keep_groups = false;
+static int get_fixed_user(const ExecContext *c, const char **user,
+ uid_t *uid, gid_t *gid,
+ const char **home, const char **shell) {
int r;
+ const char *name;
- assert(context);
+ assert(c);
+
+ if (!c->user)
+ return 0;
+
+ /* Note that we don't set $HOME or $SHELL if they are not particularly enlightening anyway
+ * (i.e. are "/" or "/bin/nologin"). */
+
+ name = c->user;
+ r = get_user_creds_clean(&name, uid, gid, home, shell);
+ if (r < 0)
+ return r;
- /* Lookup and set GID and supplementary group list. Here too
- * we avoid NSS lookups for gid=0. */
+ *user = name;
+ return 0;
+}
- if (context->group || username) {
+static int get_fixed_group(const ExecContext *c, const char **group, gid_t *gid) {
+ int r;
+ const char *name;
+
+ assert(c);
+
+ if (!c->group)
+ return 0;
+
+ name = c->group;
+ r = get_group_creds(&name, gid);
+ if (r < 0)
+ return r;
+
+ *group = name;
+ return 0;
+}
+
+static int get_supplementary_groups(const ExecContext *c, const char *user,
+ const char *group, gid_t gid,
+ gid_t **supplementary_gids, int *ngids) {
+ char **i;
+ int r, k = 0;
+ int ngroups_max;
+ bool keep_groups = false;
+ gid_t *groups = NULL;
+ _cleanup_free_ gid_t *l_gids = NULL;
+
+ assert(c);
+
+ /*
+ * If user is given, then lookup GID and supplementary groups list.
+ * We avoid NSS lookups for gid=0. Also we have to initialize groups
+ * here and as early as possible so we keep the list of supplementary
+ * groups of the caller.
+ */
+ if (user && gid_is_valid(gid) && gid != 0) {
/* First step, initialize groups from /etc/groups */
- if (username && gid != 0) {
- if (initgroups(username, gid) < 0)
- return -errno;
+ if (initgroups(user, gid) < 0)
+ return -errno;
- keep_groups = true;
- }
+ keep_groups = true;
+ }
- /* Second step, set our gids */
- if (setresgid(gid, gid, gid) < 0)
+ if (!c->supplementary_groups)
+ return 0;
+
+ /*
+ * If SupplementaryGroups= was passed then NGROUPS_MAX has to
+ * be positive, otherwise fail.
+ */
+ errno = 0;
+ ngroups_max = (int) sysconf(_SC_NGROUPS_MAX);
+ if (ngroups_max <= 0) {
+ if (errno > 0)
return -errno;
+ else
+ return -EOPNOTSUPP; /* For all other values */
}
- if (context->supplementary_groups) {
- int ngroups_max, k;
- gid_t *gids;
- char **i;
+ l_gids = new(gid_t, ngroups_max);
+ if (!l_gids)
+ return -ENOMEM;
- /* Final step, initialize any manually set supplementary groups */
- assert_se((ngroups_max = (int) sysconf(_SC_NGROUPS_MAX)) > 0);
+ if (keep_groups) {
+ /*
+ * Lookup the list of groups that the user belongs to, we
+ * avoid NSS lookups here too for gid=0.
+ */
+ k = ngroups_max;
+ if (getgrouplist(user, gid, l_gids, &k) < 0)
+ return -EINVAL;
+ } else
+ k = 0;
- if (!(gids = new(gid_t, ngroups_max)))
- return -ENOMEM;
+ STRV_FOREACH(i, c->supplementary_groups) {
+ const char *g;
- if (keep_groups) {
- k = getgroups(ngroups_max, gids);
- if (k < 0) {
- free(gids);
- return -errno;
- }
- } else
- k = 0;
+ if (k >= ngroups_max)
+ return -E2BIG;
- STRV_FOREACH(i, context->supplementary_groups) {
- const char *g;
+ g = *i;
+ r = get_group_creds(&g, l_gids+k);
+ if (r < 0)
+ return r;
- if (k >= ngroups_max) {
- free(gids);
- return -E2BIG;
- }
+ k++;
+ }
- g = *i;
- r = get_group_creds(&g, gids+k);
- if (r < 0) {
- free(gids);
- return r;
- }
+ /*
+ * Sets ngids to zero to drop all supplementary groups, happens
+ * when we are under root and SupplementaryGroups= is empty.
+ */
+ if (k == 0) {
+ *ngids = 0;
+ return 0;
+ }
- k++;
- }
+ /* Otherwise get the final list of supplementary groups */
+ groups = memdup(l_gids, sizeof(gid_t) * k);
+ if (!groups)
+ return -ENOMEM;
- if (setgroups(k, gids) < 0) {
- free(gids);
- return -errno;
- }
+ *supplementary_gids = groups;
+ *ngids = k;
+
+ groups = NULL;
+
+ return 0;
+}
+
+static int enforce_groups(const ExecContext *context, gid_t gid,
+ gid_t *supplementary_gids, int ngids) {
+ int r;
+
+ assert(context);
+
+ /* Handle SupplementaryGroups= even if it is empty */
+ if (context->supplementary_groups) {
+ r = maybe_setgroups(ngids, supplementary_gids);
+ if (r < 0)
+ return r;
+ }
- free(gids);
+ if (gid_is_valid(gid)) {
+ /* Then set our gids */
+ if (setresgid(gid, gid, gid) < 0)
+ return -errno;
}
return 0;
@@ -776,6 +891,9 @@ static int enforce_groups(const ExecContext *context, const char *username, gid_
static int enforce_user(const ExecContext *context, uid_t uid) {
assert(context);
+ if (!uid_is_valid(uid))
+ return 0;
+
/* Sets (but doesn't look up) the uid and make sure we keep the
* capabilities while doing so. */
@@ -818,14 +936,19 @@ static int null_conv(
return PAM_CONV_ERR;
}
+#endif
+
static int setup_pam(
const char *name,
const char *user,
uid_t uid,
+ gid_t gid,
const char *tty,
char ***env,
int fds[], unsigned n_fds) {
+#ifdef HAVE_PAM
+
static const struct pam_conv conv = {
.conv = null_conv,
.appdata_ptr = NULL
@@ -925,8 +1048,14 @@ static int setup_pam(
* and this will make PR_SET_PDEATHSIG work in most cases.
* If this fails, ignore the error - but expect sd-pam threads
* to fail to exit normally */
+
+ r = maybe_setgroups(0, NULL);
+ if (r < 0)
+ log_warning_errno(r, "Failed to setgroups() in sd-pam: %m");
+ if (setresgid(gid, gid, gid) < 0)
+ log_warning_errno(errno, "Failed to setresgid() in sd-pam: %m");
if (setresuid(uid, uid, uid) < 0)
- log_error_errno(r, "Error: Failed to setresuid() in sd-pam: %m");
+ log_warning_errno(errno, "Failed to setresuid() in sd-pam: %m");
(void) ignore_signals(SIGPIPE, -1);
@@ -1019,8 +1148,10 @@ fail:
closelog();
return r;
-}
+#else
+ return 0;
#endif
+}
static void rename_process_from_path(const char *path) {
char process_name[11];
@@ -1055,15 +1186,29 @@ static void rename_process_from_path(const char *path) {
#ifdef HAVE_SECCOMP
-static int apply_seccomp(const ExecContext *c) {
+static bool skip_seccomp_unavailable(const Unit* u, const char* msg) {
+
+ if (is_seccomp_available())
+ return false;
+
+ log_open();
+ log_unit_debug(u, "SECCOMP features not detected in the kernel, skipping %s", msg);
+ log_close();
+ return true;
+}
+
+static int apply_seccomp(const Unit* u, const ExecContext *c) {
uint32_t negative_action, action;
- scmp_filter_ctx *seccomp;
+ scmp_filter_ctx seccomp;
Iterator i;
void *id;
int r;
assert(c);
+ if (skip_seccomp_unavailable(u, "syscall filtering"))
+ return 0;
+
negative_action = c->syscall_errno == 0 ? SCMP_ACT_KILL : SCMP_ACT_ERRNO(c->syscall_errno);
seccomp = seccomp_init(c->syscall_whitelist ? negative_action : SCMP_ACT_ALLOW);
@@ -1104,20 +1249,23 @@ finish:
return r;
}
-static int apply_address_families(const ExecContext *c) {
- scmp_filter_ctx *seccomp;
+static int apply_address_families(const Unit* u, const ExecContext *c) {
+ scmp_filter_ctx seccomp;
Iterator i;
int r;
+#if defined(__i386__)
+ return 0;
+#endif
+
assert(c);
- seccomp = seccomp_init(SCMP_ACT_ALLOW);
- if (!seccomp)
- return -ENOMEM;
+ if (skip_seccomp_unavailable(u, "RestrictAddressFamilies="))
+ return 0;
- r = seccomp_add_secondary_archs(seccomp);
+ r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);
if (r < 0)
- goto finish;
+ return r;
if (c->address_families_whitelist) {
int af, first = 0, last = 0;
@@ -1214,10 +1362,6 @@ static int apply_address_families(const ExecContext *c) {
}
}
- r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_NNP, 0);
- if (r < 0)
- goto finish;
-
r = seccomp_load(seccomp);
finish:
@@ -1225,15 +1369,18 @@ finish:
return r;
}
-static int apply_memory_deny_write_execute(const ExecContext *c) {
- scmp_filter_ctx *seccomp;
+static int apply_memory_deny_write_execute(const Unit* u, const ExecContext *c) {
+ scmp_filter_ctx seccomp;
int r;
assert(c);
- seccomp = seccomp_init(SCMP_ACT_ALLOW);
- if (!seccomp)
- return -ENOMEM;
+ if (skip_seccomp_unavailable(u, "MemoryDenyWriteExecute="))
+ return 0;
+
+ r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);
+ if (r < 0)
+ return r;
r = seccomp_rule_add(
seccomp,
@@ -1253,7 +1400,12 @@ static int apply_memory_deny_write_execute(const ExecContext *c) {
if (r < 0)
goto finish;
- r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_NNP, 0);
+ r = seccomp_rule_add(
+ seccomp,
+ SCMP_ACT_ERRNO(EPERM),
+ SCMP_SYS(shmat),
+ 1,
+ SCMP_A2(SCMP_CMP_MASKED_EQ, SHM_EXEC, SHM_EXEC));
if (r < 0)
goto finish;
@@ -1264,22 +1416,25 @@ finish:
return r;
}
-static int apply_restrict_realtime(const ExecContext *c) {
+static int apply_restrict_realtime(const Unit* u, const ExecContext *c) {
static const int permitted_policies[] = {
SCHED_OTHER,
SCHED_BATCH,
SCHED_IDLE,
};
- scmp_filter_ctx *seccomp;
+ scmp_filter_ctx seccomp;
unsigned i;
int r, p, max_policy = 0;
assert(c);
- seccomp = seccomp_init(SCMP_ACT_ALLOW);
- if (!seccomp)
- return -ENOMEM;
+ if (skip_seccomp_unavailable(u, "RestrictRealtime="))
+ return 0;
+
+ r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);
+ if (r < 0)
+ return r;
/* Determine the highest policy constant we want to allow */
for (i = 0; i < ELEMENTSOF(permitted_policies); i++)
@@ -1323,7 +1478,34 @@ static int apply_restrict_realtime(const ExecContext *c) {
if (r < 0)
goto finish;
- r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_NNP, 0);
+ r = seccomp_load(seccomp);
+
+finish:
+ seccomp_release(seccomp);
+ return r;
+}
+
+static int apply_protect_sysctl(const 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;
+
+ r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);
+ if (r < 0)
+ return r;
+
+ r = seccomp_rule_add(
+ seccomp,
+ SCMP_ACT_ERRNO(EPERM),
+ SCMP_SYS(_sysctl),
+ 0);
if (r < 0)
goto finish;
@@ -1334,12 +1516,33 @@ finish:
return r;
}
+static int apply_protect_kernel_modules(const Unit *u, const ExecContext *c) {
+ assert(c);
+
+ /* Turn off module syscalls on ProtectKernelModules=yes */
+
+ if (skip_seccomp_unavailable(u, "ProtectKernelModules="))
+ return 0;
+
+ return seccomp_load_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_MODULE, SCMP_ACT_ERRNO(EPERM));
+}
+
+static int apply_private_devices(const Unit *u, const ExecContext *c) {
+ assert(c);
+
+ /* If PrivateDevices= is set, also turn off iopl and all @raw-io syscalls. */
+
+ if (skip_seccomp_unavailable(u, "PrivateDevices="))
+ return 0;
+
+ return seccomp_load_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_RAW_IO, SCMP_ACT_ERRNO(EPERM));
+}
+
#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]);
@@ -1366,6 +1569,7 @@ static void do_idle_pipe_dance(int idle_pipe[4]) {
}
static int build_environment(
+ Unit *u,
const ExecContext *c,
const ExecParameters *p,
unsigned n_fds,
@@ -1380,10 +1584,11 @@ static int build_environment(
unsigned n_env = 0;
char *x;
+ assert(u);
assert(c);
assert(ret);
- our_env = new0(char*, 12);
+ our_env = new0(char*, 14);
if (!our_env)
return -ENOMEM;
@@ -1408,7 +1613,7 @@ static int build_environment(
our_env[n_env++] = x;
}
- if (p->watchdog_usec > 0) {
+ if ((p->flags & EXEC_SET_WATCHDOG) && p->watchdog_usec > 0) {
if (asprintf(&x, "WATCHDOG_PID="PID_FMT, getpid()) < 0)
return -ENOMEM;
our_env[n_env++] = x;
@@ -1418,6 +1623,16 @@ static int build_environment(
our_env[n_env++] = x;
}
+ /* If this is D-Bus, tell the nss-systemd module, since it relies on being able to use D-Bus look up dynamic
+ * users via PID 1, possibly dead-locking the dbus daemon. This way it will not use D-Bus to resolve names, but
+ * check the database directly. */
+ if (unit_has_name(u, SPECIAL_DBUS_SERVICE)) {
+ x = strdup("SYSTEMD_NSS_BYPASS_BUS=1");
+ if (!x)
+ return -ENOMEM;
+ our_env[n_env++] = x;
+ }
+
if (home) {
x = strappend("HOME=", home);
if (!x)
@@ -1444,12 +1659,28 @@ static int build_environment(
our_env[n_env++] = x;
}
- if (is_terminal_input(c->std_input) ||
- c->std_output == EXEC_OUTPUT_TTY ||
- c->std_error == EXEC_OUTPUT_TTY ||
- c->tty_path) {
+ if (!sd_id128_is_null(u->invocation_id)) {
+ if (asprintf(&x, "INVOCATION_ID=" SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(u->invocation_id)) < 0)
+ return -ENOMEM;
+
+ our_env[n_env++] = x;
+ }
+
+ if (exec_context_needs_term(c)) {
+ const char *tty_path, *term = NULL;
+
+ tty_path = exec_context_tty_path(c);
+
+ /* If we are forked off PID 1 and we are supposed to operate on /dev/console, then let's try to inherit
+ * the $TERM set for PID 1. This is useful for containers so that the $TERM the container manager
+ * passes to PID 1 ends up all the way in the console login shown. */
- x = strdup(default_term_for_tty(exec_context_tty_path(c)));
+ if (path_equal(tty_path, "/dev/console") && getppid() == 1)
+ term = getenv("TERM");
+ if (!term)
+ term = default_term_for_tty(tty_path);
+
+ x = strappend("TERM=", term);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
@@ -1520,20 +1751,382 @@ 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_kernel_modules ||
+ context->protect_control_groups)
return true;
return false;
}
+static int setup_private_users(uid_t uid, gid_t gid) {
+ _cleanup_free_ char *uid_map = NULL, *gid_map = NULL;
+ _cleanup_close_pair_ int errno_pipe[2] = { -1, -1 };
+ _cleanup_close_ int unshare_ready_fd = -1;
+ _cleanup_(sigkill_waitp) pid_t pid = 0;
+ uint64_t c = 1;
+ siginfo_t si;
+ ssize_t n;
+ int r;
+
+ /* Set up a user namespace and map root to root, the selected UID/GID to itself, and everything else to
+ * nobody. In order to be able to write this mapping we need CAP_SETUID in the original user namespace, which
+ * we however lack after opening the user namespace. To work around this we fork() a temporary child process,
+ * which waits for the parent to create the new user namespace while staying in the original namespace. The
+ * child then writes the UID mapping, under full privileges. The parent waits for the child to finish and
+ * continues execution normally. */
+
+ if (uid != 0 && uid_is_valid(uid))
+ asprintf(&uid_map,
+ "0 0 1\n" /* Map root → root */
+ UID_FMT " " UID_FMT " 1\n", /* Map $UID → $UID */
+ uid, uid);
+ else
+ uid_map = strdup("0 0 1\n"); /* The case where the above is the same */
+ if (!uid_map)
+ return -ENOMEM;
+
+ if (gid != 0 && gid_is_valid(gid))
+ asprintf(&gid_map,
+ "0 0 1\n" /* Map root → root */
+ GID_FMT " " GID_FMT " 1\n", /* Map $GID → $GID */
+ gid, gid);
+ else
+ gid_map = strdup("0 0 1\n"); /* The case where the above is the same */
+ if (!gid_map)
+ return -ENOMEM;
+
+ /* Create a communication channel so that the parent can tell the child when it finished creating the user
+ * namespace. */
+ unshare_ready_fd = eventfd(0, EFD_CLOEXEC);
+ if (unshare_ready_fd < 0)
+ return -errno;
+
+ /* Create a communication channel so that the child can tell the parent a proper error code in case it
+ * failed. */
+ if (pipe2(errno_pipe, O_CLOEXEC) < 0)
+ return -errno;
+
+ pid = fork();
+ if (pid < 0)
+ return -errno;
+
+ if (pid == 0) {
+ _cleanup_close_ int fd = -1;
+ const char *a;
+ pid_t ppid;
+
+ /* Child process, running in the original user namespace. Let's update the parent's UID/GID map from
+ * here, after the parent opened its own user namespace. */
+
+ ppid = getppid();
+ errno_pipe[0] = safe_close(errno_pipe[0]);
+
+ /* Wait until the parent unshared the user namespace */
+ if (read(unshare_ready_fd, &c, sizeof(c)) < 0) {
+ r = -errno;
+ goto child_fail;
+ }
+
+ /* Disable the setgroups() system call in the child user namespace, for good. */
+ a = procfs_file_alloca(ppid, "setgroups");
+ fd = open(a, O_WRONLY|O_CLOEXEC);
+ if (fd < 0) {
+ if (errno != ENOENT) {
+ r = -errno;
+ goto child_fail;
+ }
+
+ /* If the file is missing the kernel is too old, let's continue anyway. */
+ } else {
+ if (write(fd, "deny\n", 5) < 0) {
+ r = -errno;
+ goto child_fail;
+ }
+
+ fd = safe_close(fd);
+ }
+
+ /* First write the GID map */
+ a = procfs_file_alloca(ppid, "gid_map");
+ fd = open(a, O_WRONLY|O_CLOEXEC);
+ if (fd < 0) {
+ r = -errno;
+ goto child_fail;
+ }
+ if (write(fd, gid_map, strlen(gid_map)) < 0) {
+ r = -errno;
+ goto child_fail;
+ }
+ fd = safe_close(fd);
+
+ /* The write the UID map */
+ a = procfs_file_alloca(ppid, "uid_map");
+ fd = open(a, O_WRONLY|O_CLOEXEC);
+ if (fd < 0) {
+ r = -errno;
+ goto child_fail;
+ }
+ if (write(fd, uid_map, strlen(uid_map)) < 0) {
+ r = -errno;
+ goto child_fail;
+ }
+
+ _exit(EXIT_SUCCESS);
+
+ child_fail:
+ (void) write(errno_pipe[1], &r, sizeof(r));
+ _exit(EXIT_FAILURE);
+ }
+
+ errno_pipe[1] = safe_close(errno_pipe[1]);
+
+ if (unshare(CLONE_NEWUSER) < 0)
+ return -errno;
+
+ /* Let the child know that the namespace is ready now */
+ if (write(unshare_ready_fd, &c, sizeof(c)) < 0)
+ return -errno;
+
+ /* Try to read an error code from the child */
+ n = read(errno_pipe[0], &r, sizeof(r));
+ if (n < 0)
+ return -errno;
+ if (n == sizeof(r)) { /* an error code was sent to us */
+ if (r < 0)
+ return r;
+ return -EIO;
+ }
+ if (n != 0) /* on success we should have read 0 bytes */
+ return -EIO;
+
+ r = wait_for_terminate(pid, &si);
+ if (r < 0)
+ return r;
+ pid = 0;
+
+ /* If something strange happened with the child, let's consider this fatal, too */
+ if (si.si_code != CLD_EXITED || si.si_status != 0)
+ return -EIO;
+
+ 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 int apply_mount_namespace(Unit *u, const ExecContext *context,
+ const ExecParameters *params,
+ ExecRuntime *runtime) {
+ int r;
+ _cleanup_free_ char **rw = NULL;
+ char *tmp = NULL, *var = NULL;
+ const char *root_dir = NULL;
+ NameSpaceInfo ns_info = {
+ .private_dev = context->private_devices,
+ .protect_control_groups = context->protect_control_groups,
+ .protect_kernel_tunables = context->protect_kernel_tunables,
+ .protect_kernel_modules = context->protect_kernel_modules,
+ };
+
+ assert(context);
+
+ /* The runtime struct only contains the parent of the private /tmp,
+ * which is non-accessible to world users. Inside of it there's a /tmp
+ * that is sticky, and that's the one we want to use here. */
+
+ if (context->private_tmp && runtime) {
+ if (runtime->tmp_dir)
+ tmp = strjoina(runtime->tmp_dir, "/tmp");
+ if (runtime->var_tmp_dir)
+ var = strjoina(runtime->var_tmp_dir, "/tmp");
+ }
+
+ r = compile_read_write_paths(context, params, &rw);
+ if (r < 0)
+ return r;
+
+ if (params->flags & EXEC_APPLY_CHROOT)
+ root_dir = context->root_directory;
+
+ r = setup_namespace(root_dir, &ns_info, rw,
+ context->read_only_paths,
+ context->inaccessible_paths,
+ tmp,
+ var,
+ context->protect_home,
+ context->protect_system,
+ context->mount_flags);
+
+ /* If we couldn't set up the namespace this is probably due to a
+ * missing capability. In this case, silently proceeed. */
+ if (IN_SET(r, -EPERM, -EACCES)) {
+ log_open();
+ log_unit_debug_errno(u, r, "Failed to set up namespace, assuming containerized execution, ignoring: %m");
+ log_close();
+ r = 0;
+ }
+
+ return r;
+}
+
+static int apply_working_directory(const ExecContext *context,
+ const ExecParameters *params,
+ const char *home,
+ const bool needs_mount_ns) {
+ const char *d;
+ const char *wd;
+
+ assert(context);
+
+ if (context->working_directory_home)
+ wd = home;
+ else if (context->working_directory)
+ wd = context->working_directory;
+ else
+ wd = "/";
+
+ if (params->flags & EXEC_APPLY_CHROOT) {
+ if (!needs_mount_ns && context->root_directory)
+ if (chroot(context->root_directory) < 0)
+ return -errno;
+
+ d = wd;
+ } else
+ d = strjoina(strempty(context->root_directory), "/", strempty(wd));
+
+ if (chdir(d) < 0 && !context->working_directory_missing_ok)
+ return -errno;
+
+ return 0;
+}
+
+static void append_socket_pair(int *array, unsigned *n, int pair[2]) {
+ assert(array);
+ assert(n);
+
+ if (!pair)
+ return;
+
+ if (pair[0] >= 0)
+ array[(*n)++] = pair[0];
+ if (pair[1] >= 0)
+ array[(*n)++] = pair[1];
+}
+
static int close_remaining_fds(
const ExecParameters *params,
ExecRuntime *runtime,
+ DynamicCreds *dcreds,
+ int user_lookup_fd,
int socket_fd,
int *fds, unsigned n_fds) {
unsigned n_dont_close = 0;
- int dont_close[n_fds + 7];
+ int dont_close[n_fds + 12];
assert(params);
@@ -1551,37 +2144,109 @@ static int close_remaining_fds(
n_dont_close += n_fds;
}
- if (runtime) {
- if (runtime->netns_storage_socket[0] >= 0)
- dont_close[n_dont_close++] = runtime->netns_storage_socket[0];
- if (runtime->netns_storage_socket[1] >= 0)
- dont_close[n_dont_close++] = runtime->netns_storage_socket[1];
+ if (runtime)
+ append_socket_pair(dont_close, &n_dont_close, runtime->netns_storage_socket);
+
+ if (dcreds) {
+ if (dcreds->user)
+ append_socket_pair(dont_close, &n_dont_close, dcreds->user->storage_socket);
+ if (dcreds->group)
+ append_socket_pair(dont_close, &n_dont_close, dcreds->group->storage_socket);
}
+ if (user_lookup_fd >= 0)
+ dont_close[n_dont_close++] = user_lookup_fd;
+
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 ||
+ c->protect_kernel_modules ||
+ c->private_devices ||
+ context_has_syscall_filters(c);
+}
+
+static int send_user_lookup(
+ Unit *unit,
+ int user_lookup_fd,
+ uid_t uid,
+ gid_t gid) {
+
+ assert(unit);
+
+ /* Send the resolved UID/GID to PID 1 after we learnt it. We send a single datagram, containing the UID/GID
+ * data as well as the unit name. Note that we suppress sending this if no user/group to resolve was
+ * specified. */
+
+ if (user_lookup_fd < 0)
+ return 0;
+
+ if (!uid_is_valid(uid) && !gid_is_valid(gid))
+ return 0;
+
+ if (writev(user_lookup_fd,
+ (struct iovec[]) {
+ { .iov_base = &uid, .iov_len = sizeof(uid) },
+ { .iov_base = &gid, .iov_len = sizeof(gid) },
+ { .iov_base = unit->id, .iov_len = strlen(unit->id) }}, 3) < 0)
+ return -errno;
+
+ return 0;
+}
+
static int exec_child(
Unit *unit,
ExecCommand *command,
const ExecContext *context,
const ExecParameters *params,
ExecRuntime *runtime,
+ DynamicCreds *dcreds,
char **argv,
int socket_fd,
+ int named_iofds[3],
int *fds, unsigned n_fds,
char **files_env,
+ int user_lookup_fd,
int *exit_status) {
_cleanup_strv_free_ char **our_env = NULL, **pass_env = NULL, **accum_env = NULL, **final_argv = NULL;
_cleanup_free_ char *mac_selinux_context_net = NULL;
- const char *username = NULL, *home = NULL, *shell = NULL, *wd;
+ _cleanup_free_ gid_t *supplementary_gids = NULL;
+ const char *username = NULL, *groupname = NULL;
+ const char *home = NULL, *shell = NULL;
dev_t journal_stream_dev = 0;
ino_t journal_stream_ino = 0;
bool needs_mount_namespace;
uid_t uid = UID_INVALID;
gid_t gid = GID_INVALID;
- int i, r;
+ int i, r, ngids = 0;
assert(unit);
assert(command);
@@ -1617,7 +2282,7 @@ static int exec_child(
log_forget_fds();
- r = close_remaining_fds(params, runtime, socket_fd, fds, n_fds);
+ r = close_remaining_fds(params, runtime, dcreds, user_lookup_fd, socket_fd, fds, n_fds);
if (r < 0) {
*exit_status = EXIT_FDS;
return r;
@@ -1631,7 +2296,7 @@ static int exec_child(
exec_context_tty_reset(context, params);
- if (params->confirm_spawn) {
+ if (params->flags & EXEC_CONFIRM_SPAWN) {
char response;
r = ask_for_confirmation(&response, argv);
@@ -1650,44 +2315,76 @@ static int exec_child(
}
}
- if (context->user) {
- username = context->user;
- r = get_user_creds(&username, &uid, &gid, &home, &shell);
+ if (context->dynamic_user && dcreds) {
+
+ /* Make sure we bypass our own NSS module for any NSS checks */
+ if (putenv((char*) "SYSTEMD_NSS_DYNAMIC_BYPASS=1") != 0) {
+ *exit_status = EXIT_USER;
+ return -errno;
+ }
+
+ r = dynamic_creds_realize(dcreds, &uid, &gid);
if (r < 0) {
*exit_status = EXIT_USER;
return r;
}
- }
- if (context->group) {
- const char *g = context->group;
+ if (!uid_is_valid(uid) || !gid_is_valid(gid)) {
+ *exit_status = EXIT_USER;
+ return -ESRCH;
+ }
+
+ if (dcreds->user)
+ username = dcreds->user->name;
+
+ } else {
+ r = get_fixed_user(context, &username, &uid, &gid, &home, &shell);
+ if (r < 0) {
+ *exit_status = EXIT_USER;
+ return r;
+ }
- r = get_group_creds(&g, &gid);
+ r = get_fixed_group(context, &groupname, &gid);
if (r < 0) {
*exit_status = EXIT_GROUP;
return r;
}
}
+ /* Initialize user supplementary groups and get SupplementaryGroups= ones */
+ r = get_supplementary_groups(context, username, groupname, gid,
+ &supplementary_gids, &ngids);
+ if (r < 0) {
+ *exit_status = EXIT_GROUP;
+ return r;
+ }
+
+ r = send_user_lookup(unit, user_lookup_fd, uid, gid);
+ if (r < 0) {
+ *exit_status = EXIT_USER;
+ return r;
+ }
+
+ user_lookup_fd = safe_close(user_lookup_fd);
/* If a socket is connected to STDIN/STDOUT/STDERR, we
* must sure to drop O_NONBLOCK */
if (socket_fd >= 0)
(void) fd_nonblock(socket_fd, false);
- r = setup_input(context, params, socket_fd);
+ r = setup_input(context, params, socket_fd, named_iofds);
if (r < 0) {
*exit_status = EXIT_STDIN;
return r;
}
- r = setup_output(unit, context, params, STDOUT_FILENO, socket_fd, basename(command->path), uid, gid, &journal_stream_dev, &journal_stream_ino);
+ r = setup_output(unit, context, params, STDOUT_FILENO, socket_fd, named_iofds, basename(command->path), uid, gid, &journal_stream_dev, &journal_stream_ino);
if (r < 0) {
*exit_status = EXIT_STDOUT;
return r;
}
- r = setup_output(unit, context, params, STDERR_FILENO, socket_fd, basename(command->path), uid, gid, &journal_stream_dev, &journal_stream_ino);
+ r = setup_output(unit, context, params, STDERR_FILENO, socket_fd, named_iofds, basename(command->path), uid, gid, &journal_stream_dev, &journal_stream_ino);
if (r < 0) {
*exit_status = EXIT_STDERR;
return r;
@@ -1774,7 +2471,7 @@ static int exec_child(
USER_PROCESS,
username ? "root" : context->user);
- if (context->user && is_terminal_input(context->std_input)) {
+ if (context->user) {
r = chown_terminal(STDIN_FILENO, uid);
if (r < 0) {
*exit_status = EXIT_STDIN;
@@ -1801,32 +2498,15 @@ 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;
}
}
r = build_environment(
+ unit,
context,
params,
n_fds,
@@ -1860,49 +2540,16 @@ static int exec_child(
}
accum_env = strv_env_clean(accum_env);
- umask(context->umask);
+ (void) umask(context->umask);
- if (params->apply_permissions && !command->privileged) {
- r = enforce_groups(context, username, gid);
- if (r < 0) {
- *exit_status = EXIT_GROUP;
- 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 ((params->flags & EXEC_APPLY_PERMISSIONS) && !command->privileged) {
if (context->pam_name && username) {
- r = setup_pam(context->pam_name, username, uid, context->tty_path, &accum_env, fds, n_fds);
+ r = setup_pam(context->pam_name, username, uid, gid, context->tty_path, &accum_env, fds, n_fds);
if (r < 0) {
*exit_status = EXIT_PAM;
return r;
}
}
-#endif
}
if (context->private_network && runtime && runtime->netns_storage_socket[0] >= 0) {
@@ -1914,80 +2561,37 @@ static int exec_child(
}
needs_mount_namespace = exec_needs_mount_namespace(context, params, runtime);
-
if (needs_mount_namespace) {
- char *tmp = NULL, *var = NULL;
-
- /* The runtime struct only contains the parent
- * of the private /tmp, which is
- * non-accessible to world users. Inside of it
- * there's a /tmp that is sticky, and that's
- * the one we want to use here. */
-
- if (context->private_tmp && runtime) {
- if (runtime->tmp_dir)
- tmp = strjoina(runtime->tmp_dir, "/tmp");
- if (runtime->var_tmp_dir)
- var = strjoina(runtime->var_tmp_dir, "/tmp");
- }
-
- r = setup_namespace(
- params->apply_chroot ? context->root_directory : NULL,
- context->read_write_paths,
- context->read_only_paths,
- context->inaccessible_paths,
- tmp,
- var,
- context->private_devices,
- context->protect_home,
- context->protect_system,
- context->mount_flags);
-
- /* If we couldn't set up the namespace this is
- * probably due to a missing capability. In this case,
- * silently proceeed. */
- if (r == -EPERM || r == -EACCES) {
- log_open();
- log_unit_debug_errno(unit, r, "Failed to set up namespace, assuming containerized execution, ignoring: %m");
- log_close();
- } else if (r < 0) {
+ r = apply_mount_namespace(unit, context, params, runtime);
+ if (r < 0) {
*exit_status = EXIT_NAMESPACE;
return r;
}
}
- if (context->working_directory_home)
- wd = home;
- else if (context->working_directory)
- wd = context->working_directory;
- else
- wd = "/";
-
- if (params->apply_chroot) {
- if (!needs_mount_namespace && context->root_directory)
- if (chroot(context->root_directory) < 0) {
- *exit_status = EXIT_CHROOT;
- return -errno;
- }
-
- if (chdir(wd) < 0 &&
- !context->working_directory_missing_ok) {
- *exit_status = EXIT_CHDIR;
- return -errno;
- }
- } else {
- const char *d;
+ /* Apply just after mount namespace setup */
+ r = apply_working_directory(context, params, home, needs_mount_namespace);
+ if (r < 0) {
+ *exit_status = EXIT_CHROOT;
+ return r;
+ }
- d = strjoina(strempty(context->root_directory), "/", strempty(wd));
- if (chdir(d) < 0 &&
- !context->working_directory_missing_ok) {
- *exit_status = EXIT_CHDIR;
- return -errno;
+ /* Drop groups as early as possbile */
+ if ((params->flags & EXEC_APPLY_PERMISSIONS) && !command->privileged) {
+ r = enforce_groups(context, gid, supplementary_gids, ngids);
+ if (r < 0) {
+ *exit_status = EXIT_GROUP;
+ return r;
}
}
#ifdef HAVE_SELINUX
- if (params->apply_permissions && mac_selinux_use() && params->selinux_context_net && socket_fd >= 0 && !command->privileged) {
+ if ((params->flags & EXEC_APPLY_PERMISSIONS) &&
+ mac_selinux_use() &&
+ params->selinux_context_net &&
+ socket_fd >= 0 &&
+ !command->privileged) {
+
r = mac_selinux_get_child_mls_label(socket_fd, command->path, context->selinux_context, &mac_selinux_context_net);
if (r < 0) {
*exit_status = EXIT_SELINUX_CONTEXT;
@@ -1996,6 +2600,14 @@ static int exec_child(
}
#endif
+ if ((params->flags & EXEC_APPLY_PERMISSIONS) && context->private_users) {
+ r = setup_private_users(uid, gid);
+ if (r < 0) {
+ *exit_status = EXIT_USER;
+ return r;
+ }
+ }
+
/* We repeat the fd closing here, to make sure that
* nothing is leaked from the PAM modules. Note that
* we are more aggressive this time since socket_fd
@@ -2012,13 +2624,8 @@ static int exec_child(
return r;
}
- if (params->apply_permissions && !command->privileged) {
+ 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++) {
@@ -2085,6 +2692,41 @@ static int exec_child(
}
}
+ /* Apply the MAC contexts late, but before seccomp syscall filtering, as those should really be last to
+ * influence our own codepaths as little as possible. Moreover, applying MAC contexts usually requires
+ * syscalls that are subject to seccomp filtering, hence should probably be applied before the syscalls
+ * are restricted. */
+
+#ifdef HAVE_SELINUX
+ if (mac_selinux_use()) {
+ char *exec_context = mac_selinux_context_net ?: context->selinux_context;
+
+ if (exec_context) {
+ r = setexeccon(exec_context);
+ if (r < 0) {
+ *exit_status = EXIT_SELINUX_CONTEXT;
+ return r;
+ }
+ }
+ }
+#endif
+
+ r = setup_smack(context, command);
+ if (r < 0) {
+ *exit_status = EXIT_SMACK_PROCESS_LABEL;
+ return r;
+ }
+
+#ifdef HAVE_APPARMOR
+ if (context->apparmor_profile && mac_apparmor_use()) {
+ r = aa_change_onexec(context->apparmor_profile);
+ if (r < 0 && !context->apparmor_profile_ignore) {
+ *exit_status = EXIT_APPARMOR_PROFILE;
+ return -errno;
+ }
+ }
+#endif
+
/* PR_GET_SECUREBITS is not privileged, while
* PR_SET_SECUREBITS is. So to suppress
* potential EPERMs we'll try not to call
@@ -2095,16 +2737,15 @@ 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) {
- r = apply_address_families(context);
+ if (context_has_address_families(context)) {
+ r = apply_address_families(unit, context);
if (r < 0) {
*exit_status = EXIT_ADDRESS_FAMILIES;
return r;
@@ -2112,7 +2753,7 @@ static int exec_child(
}
if (context->memory_deny_write_execute) {
- r = apply_memory_deny_write_execute(context);
+ r = apply_memory_deny_write_execute(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return r;
@@ -2120,42 +2761,44 @@ static int exec_child(
}
if (context->restrict_realtime) {
- r = apply_restrict_realtime(context);
+ r = apply_restrict_realtime(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return r;
}
}
- if (use_syscall_filter) {
- r = apply_seccomp(context);
+ if (context->protect_kernel_tunables) {
+ r = apply_protect_sysctl(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return r;
}
}
-#endif
-#ifdef HAVE_SELINUX
- if (mac_selinux_use()) {
- char *exec_context = mac_selinux_context_net ?: context->selinux_context;
+ if (context->protect_kernel_modules) {
+ r = apply_protect_kernel_modules(unit, context);
+ if (r < 0) {
+ *exit_status = EXIT_SECCOMP;
+ return r;
+ }
+ }
- if (exec_context) {
- r = setexeccon(exec_context);
- if (r < 0) {
- *exit_status = EXIT_SELINUX_CONTEXT;
- return r;
- }
+ if (context->private_devices) {
+ r = apply_private_devices(unit, context);
+ if (r < 0) {
+ *exit_status = EXIT_SECCOMP;
+ return r;
}
}
-#endif
-#ifdef HAVE_APPARMOR
- if (context->apparmor_profile && mac_apparmor_use()) {
- r = aa_change_onexec(context->apparmor_profile);
- if (r < 0 && !context->apparmor_profile_ignore) {
- *exit_status = EXIT_APPARMOR_PROFILE;
- return -errno;
+ /* This really should remain the last step before the execve(), to make sure our own code is unaffected
+ * by the filter as little as possible. */
+ if (context_has_syscall_filters(context)) {
+ r = apply_seccomp(unit, context);
+ if (r < 0) {
+ *exit_status = EXIT_SECCOMP;
+ return r;
}
}
#endif
@@ -2192,12 +2835,14 @@ int exec_spawn(Unit *unit,
const ExecContext *context,
const ExecParameters *params,
ExecRuntime *runtime,
+ DynamicCreds *dcreds,
pid_t *ret) {
_cleanup_strv_free_ char **files_env = NULL;
int *fds = NULL; unsigned n_fds = 0;
_cleanup_free_ char *line = NULL;
int socket_fd, r;
+ int named_iofds[3] = { -1, -1, -1 };
char **argv;
pid_t pid;
@@ -2224,6 +2869,10 @@ int exec_spawn(Unit *unit,
n_fds = params->n_fds;
}
+ r = exec_context_named_iofds(unit, context, params, named_iofds);
+ if (r < 0)
+ return log_unit_error_errno(unit, r, "Failed to load a named file descriptor: %m");
+
r = exec_context_load_environment(unit, context, &files_env);
if (r < 0)
return log_unit_error_errno(unit, r, "Failed to load environment files: %m");
@@ -2250,10 +2899,13 @@ int exec_spawn(Unit *unit,
context,
params,
runtime,
+ dcreds,
argv,
socket_fd,
+ named_iofds,
fds, n_fds,
files_env,
+ unit->manager->user_lookup_fds[1],
&exit_status);
if (r < 0) {
log_open();
@@ -2313,6 +2965,9 @@ void exec_context_done(ExecContext *c) {
for (l = 0; l < ELEMENTSOF(c->rlimit); l++)
c->rlimit[l] = mfree(c->rlimit[l]);
+ for (l = 0; l < 3; l++)
+ c->stdio_fdname[l] = mfree(c->stdio_fdname[l]);
+
c->working_directory = mfree(c->working_directory);
c->root_directory = mfree(c->root_directory);
c->tty_path = mfree(c->tty_path);
@@ -2411,6 +3066,56 @@ static void invalid_env(const char *p, void *userdata) {
log_unit_error(info->unit, "Ignoring invalid environment assignment '%s': %s", p, info->path);
}
+const char* exec_context_fdname(const ExecContext *c, int fd_index) {
+ assert(c);
+
+ switch (fd_index) {
+ case STDIN_FILENO:
+ if (c->std_input != EXEC_INPUT_NAMED_FD)
+ return NULL;
+ return c->stdio_fdname[STDIN_FILENO] ?: "stdin";
+ case STDOUT_FILENO:
+ if (c->std_output != EXEC_OUTPUT_NAMED_FD)
+ return NULL;
+ return c->stdio_fdname[STDOUT_FILENO] ?: "stdout";
+ case STDERR_FILENO:
+ if (c->std_error != EXEC_OUTPUT_NAMED_FD)
+ return NULL;
+ return c->stdio_fdname[STDERR_FILENO] ?: "stderr";
+ default:
+ return NULL;
+ }
+}
+
+int exec_context_named_iofds(Unit *unit, const ExecContext *c, const ExecParameters *p, int named_iofds[3]) {
+ unsigned i, targets;
+ const char *stdio_fdname[3];
+
+ assert(c);
+ assert(p);
+
+ targets = (c->std_input == EXEC_INPUT_NAMED_FD) +
+ (c->std_output == EXEC_OUTPUT_NAMED_FD) +
+ (c->std_error == EXEC_OUTPUT_NAMED_FD);
+
+ for (i = 0; i < 3; i++)
+ stdio_fdname[i] = exec_context_fdname(c, i);
+
+ for (i = 0; i < p->n_fds && targets > 0; i++)
+ if (named_iofds[STDIN_FILENO] < 0 && c->std_input == EXEC_INPUT_NAMED_FD && stdio_fdname[STDIN_FILENO] && streq(p->fd_names[i], stdio_fdname[STDIN_FILENO])) {
+ named_iofds[STDIN_FILENO] = p->fds[i];
+ targets--;
+ } else if (named_iofds[STDOUT_FILENO] < 0 && c->std_output == EXEC_OUTPUT_NAMED_FD && stdio_fdname[STDOUT_FILENO] && streq(p->fd_names[i], stdio_fdname[STDOUT_FILENO])) {
+ named_iofds[STDOUT_FILENO] = p->fds[i];
+ targets--;
+ } else if (named_iofds[STDERR_FILENO] < 0 && c->std_error == EXEC_OUTPUT_NAMED_FD && stdio_fdname[STDERR_FILENO] && streq(p->fd_names[i], stdio_fdname[STDERR_FILENO])) {
+ named_iofds[STDERR_FILENO] = p->fds[i];
+ targets--;
+ }
+
+ return (targets == 0 ? 0 : -ENOENT);
+}
+
int exec_context_load_environment(Unit *unit, const ExecContext *c, char ***l) {
char **i, **r = NULL;
@@ -2555,8 +3260,12 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
"%sRootDirectory: %s\n"
"%sNonBlocking: %s\n"
"%sPrivateTmp: %s\n"
- "%sPrivateNetwork: %s\n"
"%sPrivateDevices: %s\n"
+ "%sProtectKernelTunables: %s\n"
+ "%sProtectKernelModules: %s\n"
+ "%sProtectControlGroups: %s\n"
+ "%sPrivateNetwork: %s\n"
+ "%sPrivateUsers: %s\n"
"%sProtectHome: %s\n"
"%sProtectSystem: %s\n"
"%sIgnoreSIGPIPE: %s\n"
@@ -2567,8 +3276,12 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
prefix, c->root_directory ? c->root_directory : "/",
prefix, yes_no(c->non_blocking),
prefix, yes_no(c->private_tmp),
- prefix, yes_no(c->private_network),
prefix, yes_no(c->private_devices),
+ prefix, yes_no(c->protect_kernel_tunables),
+ prefix, yes_no(c->protect_kernel_modules),
+ 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),
prefix, protect_system_to_string(c->protect_system),
prefix, yes_no(c->ignore_sigpipe),
@@ -2723,6 +3436,8 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
if (c->group)
fprintf(f, "%sGroup: %s\n", prefix, c->group);
+ fprintf(f, "%sDynamicUser: %s\n", prefix, yes_no(c->dynamic_user));
+
if (strv_length(c->supplementary_groups) > 0) {
fprintf(f, "%sSupplementaryGroups:", prefix);
strv_fprintf(f, c->supplementary_groups);
@@ -2882,12 +3597,12 @@ void exec_status_dump(ExecStatus *s, FILE *f, const char *prefix) {
"%sPID: "PID_FMT"\n",
prefix, s->pid);
- if (s->start_timestamp.realtime > 0)
+ if (dual_timestamp_is_set(&s->start_timestamp))
fprintf(f,
"%sStart Timestamp: %s\n",
prefix, format_timestamp(buf, sizeof(buf), s->start_timestamp.realtime));
- if (s->exit_timestamp.realtime > 0)
+ if (dual_timestamp_is_set(&s->exit_timestamp))
fprintf(f,
"%sExit Timestamp: %s\n"
"%sExit Code: %s\n"
@@ -2908,7 +3623,8 @@ char *exec_command_line(char **argv) {
STRV_FOREACH(a, argv)
k += strlen(*a)+3;
- if (!(n = new(char, k)))
+ n = new(char, k);
+ if (!n)
return NULL;
p = n;
@@ -3097,9 +3813,7 @@ ExecRuntime *exec_runtime_unref(ExecRuntime *r) {
free(r->tmp_dir);
free(r->var_tmp_dir);
safe_close_pair(r->netns_storage_socket);
- free(r);
-
- return NULL;
+ return mfree(r);
}
int exec_runtime_serialize(Unit *u, ExecRuntime *rt, FILE *f, FDSet *fds) {
@@ -3255,7 +3969,8 @@ static const char* const exec_input_table[_EXEC_INPUT_MAX] = {
[EXEC_INPUT_TTY] = "tty",
[EXEC_INPUT_TTY_FORCE] = "tty-force",
[EXEC_INPUT_TTY_FAIL] = "tty-fail",
- [EXEC_INPUT_SOCKET] = "socket"
+ [EXEC_INPUT_SOCKET] = "socket",
+ [EXEC_INPUT_NAMED_FD] = "fd",
};
DEFINE_STRING_TABLE_LOOKUP(exec_input, ExecInput);
@@ -3270,7 +3985,8 @@ static const char* const exec_output_table[_EXEC_OUTPUT_MAX] = {
[EXEC_OUTPUT_KMSG_AND_CONSOLE] = "kmsg+console",
[EXEC_OUTPUT_JOURNAL] = "journal",
[EXEC_OUTPUT_JOURNAL_AND_CONSOLE] = "journal+console",
- [EXEC_OUTPUT_SOCKET] = "socket"
+ [EXEC_OUTPUT_SOCKET] = "socket",
+ [EXEC_OUTPUT_NAMED_FD] = "fd",
};
DEFINE_STRING_TABLE_LOOKUP(exec_output, ExecOutput);
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-12-18 02:08:24 +0000