summaryrefslogtreecommitdiff
path: root/src/core
diff options
context:
space:
mode:
Diffstat (limited to 'src/core')
-rw-r--r--src/core/dynamic-user.c51
-rw-r--r--src/core/execute.c15
2 files changed, 59 insertions, 7 deletions
diff --git a/src/core/dynamic-user.c b/src/core/dynamic-user.c
index 8035bee231..185d0e5f00 100644
--- a/src/core/dynamic-user.c
+++ b/src/core/dynamic-user.c
@@ -150,6 +150,42 @@ int dynamic_user_acquire(Manager *m, const char *name, DynamicUser** ret) {
return 1;
}
+static int make_uid_symlinks(uid_t uid, const char *name, bool b) {
+
+ char path1[strlen("/run/systemd/dynamic-uid/direct:") + DECIMAL_STR_MAX(uid_t) + 1];
+ const char *path2;
+ int r = 0;
+
+ /* Add direct additional symlinks for direct lookups of dynamic UIDs and their names by userspace code. The
+ * only reason we have this is because dbus-daemon cannot use D-Bus for resolving users and groups (since it
+ * would be its own client then). We hence keep these world-readable symlinks in place, so that the
+ * unprivileged dbus user can read the mappings when it needs them via these symlinks instead of having to go
+ * via the bus. Ideally, we'd use the lock files we keep for this anyway, but we can't since we use BSD locks
+ * on them and as those may be taken by any user with read access we can't make them world-readable. */
+
+ xsprintf(path1, "/run/systemd/dynamic-uid/direct:" UID_FMT, uid);
+ if (unlink(path1) < 0) {
+ if (errno != ENOENT)
+ r = -errno;
+ }
+ if (b) {
+ if (symlink(name, path1) < 0)
+ r = -errno;
+ }
+
+ path2 = strjoina("/run/systemd/dynamic-uid/direct:", name);
+ if (unlink(path2) < 0) {
+ if (errno != ENOENT)
+ r = -errno;
+ }
+ if (b) {
+ if (symlink(path1 + strlen("/run/systemd/dynamic-uid/direct:"), path2) < 0)
+ r = -errno;
+ }
+
+ return r;
+}
+
static int pick_uid(const char *name, uid_t *ret_uid) {
static const uint8_t hash_key[] = {
@@ -223,6 +259,7 @@ static int pick_uid(const char *name, uid_t *ret_uid) {
}
(void) ftruncate(lock_fd, l);
+ (void) make_uid_symlinks(candidate, name, true); /* also add direct lookup symlinks */
*ret_uid = candidate;
r = lock_fd;
@@ -324,14 +361,16 @@ static int dynamic_user_push(DynamicUser *d, uid_t uid, int lock_fd) {
return 0;
}
-static void unlink_uid_lock(int lock_fd, uid_t uid) {
+static void unlink_uid_lock(int lock_fd, uid_t uid, const char *name) {
char lock_path[strlen("/run/systemd/dynamic-uid/") + DECIMAL_STR_MAX(uid_t) + 1];
if (lock_fd < 0)
return;
xsprintf(lock_path, "/run/systemd/dynamic-uid/" UID_FMT, uid);
- (void) unlink_noerrno(lock_path);
+ (void) unlink(lock_path);
+
+ (void) make_uid_symlinks(uid, name, false); /* remove direct lookup symlinks */
}
int dynamic_user_realize(DynamicUser *d, uid_t *ret) {
@@ -399,7 +438,7 @@ int dynamic_user_realize(DynamicUser *d, uid_t *ret) {
/* So, we found a working UID/lock combination. Let's see if we actually still need it. */
if (lockf(d->storage_socket[0], F_LOCK, 0) < 0) {
- unlink_uid_lock(uid_lock_fd, uid);
+ unlink_uid_lock(uid_lock_fd, uid, d->name);
return -errno;
}
@@ -407,7 +446,7 @@ int dynamic_user_realize(DynamicUser *d, uid_t *ret) {
if (r < 0) {
if (r != -EAGAIN) {
/* OK, something bad happened, let's get rid of the bits we acquired. */
- unlink_uid_lock(uid_lock_fd, uid);
+ unlink_uid_lock(uid_lock_fd, uid, d->name);
goto finish;
}
@@ -416,7 +455,7 @@ int dynamic_user_realize(DynamicUser *d, uid_t *ret) {
/* Hmm, so as it appears there's now something stored in the storage socket. Throw away what we
* acquired, and use what's stored now. */
- unlink_uid_lock(uid_lock_fd, uid);
+ unlink_uid_lock(uid_lock_fd, uid, d->name);
safe_close(uid_lock_fd);
uid = new_uid;
@@ -513,7 +552,7 @@ static int dynamic_user_close(DynamicUser *d) {
goto finish;
/* This dynamic user was realized and dynamically allocated. In this case, let's remove the lock file. */
- unlink_uid_lock(lock_fd, uid);
+ unlink_uid_lock(lock_fd, uid, d->name);
r = 1;
finish:
diff --git a/src/core/execute.c b/src/core/execute.c
index 4c786a2e33..0af8eb5a02 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -91,6 +91,7 @@
#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"
@@ -1384,6 +1385,7 @@ 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,
@@ -1401,7 +1403,7 @@ static int build_environment(
assert(c);
assert(ret);
- our_env = new0(char*, 12);
+ our_env = new0(char*, 13);
if (!our_env)
return -ENOMEM;
@@ -1436,6 +1438,16 @@ 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)
@@ -2100,6 +2112,7 @@ static int exec_child(
}
r = build_environment(
+ unit,
context,
params,
n_fds,