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-rw-r--r--src/shared/capability.c71
-rw-r--r--src/shared/capability.h2
-rw-r--r--src/shared/util.c3
-rw-r--r--src/timesync/timesyncd.c68
4 files changed, 74 insertions, 70 deletions
diff --git a/src/shared/capability.c b/src/shared/capability.c
index b49c514009..69e054b1ff 100644
--- a/src/shared/capability.c
+++ b/src/shared/capability.c
@@ -29,12 +29,13 @@
#include <ctype.h>
#include <sys/capability.h>
#include <sys/prctl.h>
+#include "grp.h"
#include "macro.h"
-#include "capability.h"
#include "util.h"
#include "log.h"
#include "fileio.h"
+#include "capability.h"
int have_effective_cap(int value) {
_cleanup_cap_free_ cap_t cap;
@@ -212,3 +213,71 @@ int capability_bounding_set_drop_usermode(uint64_t drop) {
return r;
}
+
+int drop_privileges(uid_t uid, gid_t gid, uint64_t keep_capabilites) {
+
+ _cleanup_cap_free_ cap_t d = NULL;
+ cap_value_t bits[sizeof(keep_capabilites)*8];
+ unsigned i, j = 0;
+ int r;
+
+ /* Unfortunately we cannot leave privilege dropping to PID 1
+ * here, since we want to run as user but want to keep some
+ * capabilities. Since file capabilities have been introduced
+ * this cannot be done across exec() anymore, unless our
+ * binary has the capability configured in the file system,
+ * which we want to avoid. */
+
+ if (setresgid(gid, gid, gid) < 0) {
+ log_error("Failed change group ID: %m");
+ return -errno;
+ }
+
+ if (setgroups(0, NULL) < 0) {
+ log_error("Failed to drop auxiliary groups list: %m");
+ return -errno;
+ }
+
+ if (prctl(PR_SET_KEEPCAPS, 1) < 0) {
+ log_error("Failed to enable keep capabilities flag: %m");
+ return -errno;
+ }
+
+ r = setresuid(uid, uid, uid);
+ if (r < 0) {
+ log_error("Failed change user ID: %m");
+ return -errno;
+ }
+
+ if (prctl(PR_SET_KEEPCAPS, 0) < 0) {
+ log_error("Failed to disable keep capabilities flag: %m");
+ return -errno;
+ }
+
+ r = capability_bounding_set_drop(~keep_capabilites, true);
+ if (r < 0) {
+ log_error("Failed to drop capabilities: %s", strerror(-r));
+ return r;
+ }
+
+ d = cap_init();
+ if (!d)
+ return log_oom();
+
+ for (i = 0; i < sizeof(keep_capabilites)*8; i++)
+ if (keep_capabilites & (1ULL << i))
+ bits[j++] = i;
+
+ if (cap_set_flag(d, CAP_EFFECTIVE, j, bits, CAP_SET) < 0 ||
+ cap_set_flag(d, CAP_PERMITTED, j, bits, CAP_SET) < 0) {
+ log_error("Failed to enable capabilities bits: %m");
+ return -errno;
+ }
+
+ if (cap_set_proc(d) < 0) {
+ log_error("Failed to increase capabilities: %m");
+ return -errno;
+ }
+
+ return 0;
+}
diff --git a/src/shared/capability.h b/src/shared/capability.h
index 64f86410ab..3e6d9995f5 100644
--- a/src/shared/capability.h
+++ b/src/shared/capability.h
@@ -32,6 +32,8 @@ int have_effective_cap(int value);
int capability_bounding_set_drop(uint64_t drop, bool right_now);
int capability_bounding_set_drop_usermode(uint64_t drop);
+int drop_privileges(uid_t uid, gid_t gid, uint64_t keep_capabilites);
+
DEFINE_TRIVIAL_CLEANUP_FUNC(cap_t, cap_free);
#define _cleanup_cap_free_ _cleanup_(cap_freep)
diff --git a/src/shared/util.c b/src/shared/util.c
index 17b0ae16cf..4a3e35f356 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -6480,8 +6480,7 @@ void hexdump(FILE *f, const void *p, size_t s) {
}
}
-int update_reboot_param_file(const char *param)
-{
+int update_reboot_param_file(const char *param) {
int r = 0;
if (param) {
diff --git a/src/timesync/timesyncd.c b/src/timesync/timesyncd.c
index a56bbc30ca..27f6b2d226 100644
--- a/src/timesync/timesyncd.c
+++ b/src/timesync/timesyncd.c
@@ -1196,72 +1196,6 @@ static int manager_network_monitor_listen(Manager *m) {
return 0;
}
-static int drop_privileges(uid_t uid, gid_t gid) {
-
- static const cap_value_t bits[] = {
- CAP_SYS_TIME,
- };
-
- _cleanup_cap_free_ cap_t d = NULL;
- int r;
-
- /* Unfortunately we cannot leave privilege dropping to PID 1
- * here, since we want to run as user but want to keep te
- * CAP_SYS_TIME capability. Since file capabilities have been
- * introduced this cannot be done across exec() anymore,
- * unless our binary has the capability configured in the file
- * system, which we want to avoid. */
-
- if (setresgid(gid, gid, gid) < 0) {
- log_error("Failed change group ID: %m");
- return -errno;
- }
-
- if (setgroups(0, NULL) < 0) {
- log_error("Failed to drop auxiliary groups list: %m");
- return -errno;
- }
-
- if (prctl(PR_SET_KEEPCAPS, 1) < 0) {
- log_error("Failed to enable keep capabilities flag: %m");
- return -errno;
- }
-
- r = setresuid(uid, uid, uid);
- if (r < 0) {
- log_error("Failed change user ID: %m");
- return -errno;
- }
-
- if (prctl(PR_SET_KEEPCAPS, 0) < 0) {
- log_error("Failed to disable keep capabilities flag: %m");
- return -errno;
- }
-
- r = capability_bounding_set_drop(~(1ULL << CAP_SYS_TIME), true);
- if (r < 0) {
- log_error("Failed to drop capabilities: %s", strerror(-r));
- return r;
- }
-
- d = cap_init();
- if (!d)
- return log_oom();
-
- if (cap_set_flag(d, CAP_EFFECTIVE, ELEMENTSOF(bits), bits, CAP_SET) < 0 ||
- cap_set_flag(d, CAP_PERMITTED, ELEMENTSOF(bits), bits, CAP_SET) < 0) {
- log_error("Failed to enable capabilities bits: %m");
- return -errno;
- }
-
- if (cap_set_proc(d) < 0) {
- log_error("Failed to increase capabilities: %m");
- return -errno;
- }
-
- return 0;
-}
-
int main(int argc, char *argv[]) {
const char *user = "systemd-timesync";
_cleanup_manager_free_ Manager *m = NULL;
@@ -1291,7 +1225,7 @@ int main(int argc, char *argv[]) {
if (r < 0)
goto out;
- r = drop_privileges(uid, gid);
+ r = drop_privileges(uid, gid, (1ULL << CAP_SYS_TIME));
if (r < 0)
goto out;
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-29 00:03:36 +0000