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-rw-r--r--src/shared/clean-ipc.c452
1 files changed, 452 insertions, 0 deletions
diff --git a/src/shared/clean-ipc.c b/src/shared/clean-ipc.c
new file mode 100644
index 0000000..bbb343f
--- /dev/null
+++ b/src/shared/clean-ipc.c
@@ -0,0 +1,452 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <mqueue.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <sys/ipc.h>
+#include <sys/msg.h>
+#include <sys/sem.h>
+#include <sys/shm.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "clean-ipc.h"
+#include "dirent-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "format-util.h"
+#include "log.h"
+#include "macro.h"
+#include "string-util.h"
+#include "strv.h"
+#include "user-util.h"
+
+static bool match_uid_gid(uid_t subject_uid, gid_t subject_gid, uid_t delete_uid, gid_t delete_gid) {
+
+ if (uid_is_valid(delete_uid) && subject_uid == delete_uid)
+ return true;
+
+ if (gid_is_valid(delete_gid) && subject_gid == delete_gid)
+ return true;
+
+ return false;
+}
+
+static int clean_sysvipc_shm(uid_t delete_uid, gid_t delete_gid, bool rm) {
+ _cleanup_fclose_ FILE *f = NULL;
+ bool first = true;
+ int ret = 0, r;
+
+ f = fopen("/proc/sysvipc/shm", "re");
+ if (!f) {
+ if (errno == ENOENT)
+ return 0;
+
+ return log_warning_errno(errno, "Failed to open /proc/sysvipc/shm: %m");
+ }
+
+ for (;;) {
+ _cleanup_free_ char *line = NULL;
+ unsigned n_attached;
+ pid_t cpid, lpid;
+ uid_t uid, cuid;
+ gid_t gid, cgid;
+ int shmid;
+
+ r = read_line(f, LONG_LINE_MAX, &line);
+ if (r < 0)
+ return log_warning_errno(errno, "Failed to read /proc/sysvipc/shm: %m");
+ if (r == 0)
+ break;
+
+ if (first) {
+ first = false;
+ continue;
+ }
+
+ if (sscanf(line, "%*i %i %*o %*u " PID_FMT " " PID_FMT " %u " UID_FMT " " GID_FMT " " UID_FMT " " GID_FMT,
+ &shmid, &cpid, &lpid, &n_attached, &uid, &gid, &cuid, &cgid) != 8)
+ continue;
+
+ if (n_attached > 0)
+ continue;
+
+ if (!match_uid_gid(uid, gid, delete_uid, delete_gid))
+ continue;
+
+ if (!rm)
+ return 1;
+
+ if (shmctl(shmid, IPC_RMID, NULL) < 0) {
+
+ /* Ignore entries that are already deleted */
+ if (IN_SET(errno, EIDRM, EINVAL))
+ continue;
+
+ ret = log_warning_errno(errno,
+ "Failed to remove SysV shared memory segment %i: %m",
+ shmid);
+ } else {
+ log_debug("Removed SysV shared memory segment %i.", shmid);
+ if (ret == 0)
+ ret = 1;
+ }
+ }
+
+ return ret;
+}
+
+static int clean_sysvipc_sem(uid_t delete_uid, gid_t delete_gid, bool rm) {
+ _cleanup_fclose_ FILE *f = NULL;
+ bool first = true;
+ int ret = 0, r;
+
+ f = fopen("/proc/sysvipc/sem", "re");
+ if (!f) {
+ if (errno == ENOENT)
+ return 0;
+
+ return log_warning_errno(errno, "Failed to open /proc/sysvipc/sem: %m");
+ }
+
+ for (;;) {
+ _cleanup_free_ char *line = NULL;
+ uid_t uid, cuid;
+ gid_t gid, cgid;
+ int semid;
+
+ r = read_line(f, LONG_LINE_MAX, &line);
+ if (r < 0)
+ return log_warning_errno(r, "Failed to read /proc/sysvipc/sem: %m");
+ if (r == 0)
+ break;
+
+ if (first) {
+ first = false;
+ continue;
+ }
+
+ if (sscanf(line, "%*i %i %*o %*u " UID_FMT " " GID_FMT " " UID_FMT " " GID_FMT,
+ &semid, &uid, &gid, &cuid, &cgid) != 5)
+ continue;
+
+ if (!match_uid_gid(uid, gid, delete_uid, delete_gid))
+ continue;
+
+ if (!rm)
+ return 1;
+
+ if (semctl(semid, 0, IPC_RMID) < 0) {
+
+ /* Ignore entries that are already deleted */
+ if (IN_SET(errno, EIDRM, EINVAL))
+ continue;
+
+ ret = log_warning_errno(errno,
+ "Failed to remove SysV semaphores object %i: %m",
+ semid);
+ } else {
+ log_debug("Removed SysV semaphore %i.", semid);
+ if (ret == 0)
+ ret = 1;
+ }
+ }
+
+ return ret;
+}
+
+static int clean_sysvipc_msg(uid_t delete_uid, gid_t delete_gid, bool rm) {
+ _cleanup_fclose_ FILE *f = NULL;
+ bool first = true;
+ int ret = 0, r;
+
+ f = fopen("/proc/sysvipc/msg", "re");
+ if (!f) {
+ if (errno == ENOENT)
+ return 0;
+
+ return log_warning_errno(errno, "Failed to open /proc/sysvipc/msg: %m");
+ }
+
+ for (;;) {
+ _cleanup_free_ char *line = NULL;
+ uid_t uid, cuid;
+ gid_t gid, cgid;
+ pid_t cpid, lpid;
+ int msgid;
+
+ r = read_line(f, LONG_LINE_MAX, &line);
+ if (r < 0)
+ return log_warning_errno(r, "Failed to read /proc/sysvipc/msg: %m");
+ if (r == 0)
+ break;
+
+ if (first) {
+ first = false;
+ continue;
+ }
+
+ if (sscanf(line, "%*i %i %*o %*u %*u " PID_FMT " " PID_FMT " " UID_FMT " " GID_FMT " " UID_FMT " " GID_FMT,
+ &msgid, &cpid, &lpid, &uid, &gid, &cuid, &cgid) != 7)
+ continue;
+
+ if (!match_uid_gid(uid, gid, delete_uid, delete_gid))
+ continue;
+
+ if (!rm)
+ return 1;
+
+ if (msgctl(msgid, IPC_RMID, NULL) < 0) {
+
+ /* Ignore entries that are already deleted */
+ if (IN_SET(errno, EIDRM, EINVAL))
+ continue;
+
+ ret = log_warning_errno(errno,
+ "Failed to remove SysV message queue %i: %m",
+ msgid);
+ } else {
+ log_debug("Removed SysV message queue %i.", msgid);
+ if (ret == 0)
+ ret = 1;
+ }
+ }
+
+ return ret;
+}
+
+static int clean_posix_shm_internal(const char *dirname, DIR *dir, uid_t uid, gid_t gid, bool rm) {
+ int ret = 0, r;
+
+ assert(dir);
+
+ FOREACH_DIRENT_ALL(de, dir, goto fail) {
+ struct stat st;
+
+ if (dot_or_dot_dot(de->d_name))
+ continue;
+
+ if (fstatat(dirfd(dir), de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
+ if (errno == ENOENT)
+ continue;
+
+ ret = log_warning_errno(errno, "Failed to stat() POSIX shared memory segment %s/%s: %m",
+ dirname, de->d_name);
+ continue;
+ }
+
+ if (S_ISDIR(st.st_mode)) {
+ _cleanup_closedir_ DIR *kid = NULL;
+
+ kid = xopendirat(dirfd(dir), de->d_name, O_NOFOLLOW|O_NOATIME);
+ if (!kid) {
+ if (errno != ENOENT)
+ ret = log_warning_errno(errno, "Failed to enter shared memory directory %s/%s: %m",
+ dirname, de->d_name);
+ } else {
+ r = clean_posix_shm_internal(de->d_name, kid, uid, gid, rm);
+ if (r < 0)
+ ret = r;
+ }
+
+ if (!match_uid_gid(st.st_uid, st.st_gid, uid, gid))
+ continue;
+
+ if (!rm)
+ return 1;
+
+ if (unlinkat(dirfd(dir), de->d_name, AT_REMOVEDIR) < 0) {
+
+ if (errno == ENOENT)
+ continue;
+
+ ret = log_warning_errno(errno, "Failed to remove POSIX shared memory directory %s/%s: %m",
+ dirname, de->d_name);
+ } else {
+ log_debug("Removed POSIX shared memory directory %s", de->d_name);
+ if (ret == 0)
+ ret = 1;
+ }
+ } else {
+
+ if (!match_uid_gid(st.st_uid, st.st_gid, uid, gid))
+ continue;
+
+ if (!rm)
+ return 1;
+
+ if (unlinkat(dirfd(dir), de->d_name, 0) < 0) {
+
+ if (errno == ENOENT)
+ continue;
+
+ ret = log_warning_errno(errno, "Failed to remove POSIX shared memory segment %s: %m", de->d_name);
+ } else {
+ log_debug("Removed POSIX shared memory segment %s", de->d_name);
+ if (ret == 0)
+ ret = 1;
+ }
+ }
+ }
+
+ return ret;
+
+fail:
+ return log_warning_errno(errno, "Failed to read /dev/shm: %m");
+}
+
+static int clean_posix_shm(uid_t uid, gid_t gid, bool rm) {
+ _cleanup_closedir_ DIR *dir = NULL;
+
+ dir = opendir("/dev/shm");
+ if (!dir) {
+ if (errno == ENOENT)
+ return 0;
+
+ return log_warning_errno(errno, "Failed to open /dev/shm: %m");
+ }
+
+ return clean_posix_shm_internal("/dev/shm", dir, uid, gid, rm);
+}
+
+static int clean_posix_mq(uid_t uid, gid_t gid, bool rm) {
+ _cleanup_closedir_ DIR *dir = NULL;
+ int ret = 0;
+
+ dir = opendir("/dev/mqueue");
+ if (!dir) {
+ if (errno == ENOENT)
+ return 0;
+
+ return log_warning_errno(errno, "Failed to open /dev/mqueue: %m");
+ }
+
+ FOREACH_DIRENT_ALL(de, dir, goto fail) {
+ struct stat st;
+ char fn[1+strlen(de->d_name)+1];
+
+ if (dot_or_dot_dot(de->d_name))
+ continue;
+
+ if (fstatat(dirfd(dir), de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
+ if (errno == ENOENT)
+ continue;
+
+ ret = log_warning_errno(errno,
+ "Failed to stat() MQ segment %s: %m",
+ de->d_name);
+ continue;
+ }
+
+ if (!match_uid_gid(st.st_uid, st.st_gid, uid, gid))
+ continue;
+
+ if (!rm)
+ return 1;
+
+ fn[0] = '/';
+ strcpy(fn+1, de->d_name);
+
+ if (mq_unlink(fn) < 0) {
+ if (errno == ENOENT)
+ continue;
+
+ ret = log_warning_errno(errno,
+ "Failed to unlink POSIX message queue %s: %m",
+ fn);
+ } else {
+ log_debug("Removed POSIX message queue %s", fn);
+ if (ret == 0)
+ ret = 1;
+ }
+ }
+
+ return ret;
+
+fail:
+ return log_warning_errno(errno, "Failed to read /dev/mqueue: %m");
+}
+
+int clean_ipc_internal(uid_t uid, gid_t gid, bool rm) {
+ int ret = 0, r;
+
+ /* If 'rm' is true, clean all IPC objects owned by either the specified UID or the specified GID. Return the
+ * last error encountered or == 0 if no matching IPC objects have been found or > 0 if matching IPC objects
+ * have been found and have been removed.
+ *
+ * If 'rm' is false, just search for IPC objects owned by either the specified UID or the specified GID. In
+ * this case we return < 0 on error, > 0 if we found a matching object, == 0 if we didn't.
+ *
+ * As special rule: if UID/GID is specified as root we'll silently not clean up things, and always claim that
+ * there are IPC objects for it. */
+
+ if (uid == 0) {
+ if (!rm)
+ return 1;
+
+ uid = UID_INVALID;
+ }
+ if (gid == 0) {
+ if (!rm)
+ return 1;
+
+ gid = GID_INVALID;
+ }
+
+ /* Anything to do? */
+ if (!uid_is_valid(uid) && !gid_is_valid(gid))
+ return 0;
+
+ r = clean_sysvipc_shm(uid, gid, rm);
+ if (r != 0) {
+ if (!rm)
+ return r;
+ if (ret == 0)
+ ret = r;
+ }
+
+ r = clean_sysvipc_sem(uid, gid, rm);
+ if (r != 0) {
+ if (!rm)
+ return r;
+ if (ret == 0)
+ ret = r;
+ }
+
+ r = clean_sysvipc_msg(uid, gid, rm);
+ if (r != 0) {
+ if (!rm)
+ return r;
+ if (ret == 0)
+ ret = r;
+ }
+
+ r = clean_posix_shm(uid, gid, rm);
+ if (r != 0) {
+ if (!rm)
+ return r;
+ if (ret == 0)
+ ret = r;
+ }
+
+ r = clean_posix_mq(uid, gid, rm);
+ if (r != 0) {
+ if (!rm)
+ return r;
+ if (ret == 0)
+ ret = r;
+ }
+
+ return ret;
+}
+
+int clean_ipc_by_uid(uid_t uid) {
+ return clean_ipc_internal(uid, GID_INVALID, true);
+}
+
+int clean_ipc_by_gid(gid_t gid) {
+ return clean_ipc_internal(UID_INVALID, gid, true);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-01 17:27:20 +0000