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-rw-r--r--src/libshared/clean-ipc.c365
1 files changed, 365 insertions, 0 deletions
diff --git a/src/libshared/clean-ipc.c b/src/libshared/clean-ipc.c
new file mode 100644
index 0000000000..a3ac7aeb82
--- /dev/null
+++ b/src/libshared/clean-ipc.c
@@ -0,0 +1,365 @@
+/***
+ This file is part of systemd.
+
+ Copyright 2014 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <mqueue.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.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 "formats-util.h"
+#include "log.h"
+#include "macro.h"
+#include "string-util.h"
+#include "strv.h"
+
+static int clean_sysvipc_shm(uid_t delete_uid) {
+ _cleanup_fclose_ FILE *f = NULL;
+ char line[LINE_MAX];
+ bool first = true;
+ int ret = 0;
+
+ 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");
+ }
+
+ FOREACH_LINE(line, f, goto fail) {
+ unsigned n_attached;
+ pid_t cpid, lpid;
+ uid_t uid, cuid;
+ gid_t gid, cgid;
+ int shmid;
+
+ if (first) {
+ first = false;
+ continue;
+ }
+
+ truncate_nl(line);
+
+ 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 (uid != delete_uid)
+ continue;
+
+ if (shmctl(shmid, IPC_RMID, NULL) < 0) {
+
+ /* Ignore entries that are already deleted */
+ if (errno == EIDRM || errno == EINVAL)
+ continue;
+
+ ret = log_warning_errno(errno,
+ "Failed to remove SysV shared memory segment %i: %m",
+ shmid);
+ }
+ }
+
+ return ret;
+
+fail:
+ return log_warning_errno(errno, "Failed to read /proc/sysvipc/shm: %m");
+}
+
+static int clean_sysvipc_sem(uid_t delete_uid) {
+ _cleanup_fclose_ FILE *f = NULL;
+ char line[LINE_MAX];
+ bool first = true;
+ int ret = 0;
+
+ 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");
+ }
+
+ FOREACH_LINE(line, f, goto fail) {
+ uid_t uid, cuid;
+ gid_t gid, cgid;
+ int semid;
+
+ if (first) {
+ first = false;
+ continue;
+ }
+
+ truncate_nl(line);
+
+ if (sscanf(line, "%*i %i %*o %*u " UID_FMT " " GID_FMT " " UID_FMT " " GID_FMT,
+ &semid, &uid, &gid, &cuid, &cgid) != 5)
+ continue;
+
+ if (uid != delete_uid)
+ continue;
+
+ if (semctl(semid, 0, IPC_RMID) < 0) {
+
+ /* Ignore entries that are already deleted */
+ if (errno == EIDRM || errno == EINVAL)
+ continue;
+
+ ret = log_warning_errno(errno,
+ "Failed to remove SysV semaphores object %i: %m",
+ semid);
+ }
+ }
+
+ return ret;
+
+fail:
+ return log_warning_errno(errno, "Failed to read /proc/sysvipc/sem: %m");
+}
+
+static int clean_sysvipc_msg(uid_t delete_uid) {
+ _cleanup_fclose_ FILE *f = NULL;
+ char line[LINE_MAX];
+ bool first = true;
+ int ret = 0;
+
+ 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");
+ }
+
+ FOREACH_LINE(line, f, goto fail) {
+ uid_t uid, cuid;
+ gid_t gid, cgid;
+ pid_t cpid, lpid;
+ int msgid;
+
+ if (first) {
+ first = false;
+ continue;
+ }
+
+ truncate_nl(line);
+
+ 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 (uid != delete_uid)
+ continue;
+
+ if (msgctl(msgid, IPC_RMID, NULL) < 0) {
+
+ /* Ignore entries that are already deleted */
+ if (errno == EIDRM || errno == EINVAL)
+ continue;
+
+ ret = log_warning_errno(errno,
+ "Failed to remove SysV message queue %i: %m",
+ msgid);
+ }
+ }
+
+ return ret;
+
+fail:
+ return log_warning_errno(errno, "Failed to read /proc/sysvipc/msg: %m");
+}
+
+static int clean_posix_shm_internal(DIR *dir, uid_t uid) {
+ struct dirent *de;
+ int ret = 0, r;
+
+ assert(dir);
+
+ FOREACH_DIRENT(de, dir, goto fail) {
+ struct stat st;
+
+ if (STR_IN_SET(de->d_name, "..", "."))
+ continue;
+
+ if (fstatat(dirfd(dir), de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
+ if (errno == ENOENT)
+ continue;
+
+ log_warning_errno(errno, "Failed to stat() POSIX shared memory segment %s: %m", de->d_name);
+ ret = -errno;
+ continue;
+ }
+
+ if (st.st_uid != uid)
+ continue;
+
+ if (S_ISDIR(st.st_mode)) {
+ _cleanup_closedir_ DIR *kid;
+
+ kid = xopendirat(dirfd(dir), de->d_name, O_NOFOLLOW|O_NOATIME);
+ if (!kid) {
+ if (errno != ENOENT) {
+ log_warning_errno(errno, "Failed to enter shared memory directory %s: %m", de->d_name);
+ ret = -errno;
+ }
+ } else {
+ r = clean_posix_shm_internal(kid, uid);
+ if (r < 0)
+ ret = r;
+ }
+
+ if (unlinkat(dirfd(dir), de->d_name, AT_REMOVEDIR) < 0) {
+
+ if (errno == ENOENT)
+ continue;
+
+ log_warning_errno(errno, "Failed to remove POSIX shared memory directory %s: %m", de->d_name);
+ ret = -errno;
+ }
+ } else {
+
+ if (unlinkat(dirfd(dir), de->d_name, 0) < 0) {
+
+ if (errno == ENOENT)
+ continue;
+
+ log_warning_errno(errno, "Failed to remove POSIX shared memory segment %s: %m", de->d_name);
+ ret = -errno;
+ }
+ }
+ }
+
+ return ret;
+
+fail:
+ log_warning_errno(errno, "Failed to read /dev/shm: %m");
+ return -errno;
+}
+
+static int clean_posix_shm(uid_t uid) {
+ _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(dir, uid);
+}
+
+static int clean_posix_mq(uid_t uid) {
+ _cleanup_closedir_ DIR *dir = NULL;
+ struct dirent *de;
+ 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(de, dir, goto fail) {
+ struct stat st;
+ char fn[1+strlen(de->d_name)+1];
+
+ if (STR_IN_SET(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 (st.st_uid != uid)
+ continue;
+
+ 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);
+ }
+ }
+
+ return ret;
+
+fail:
+ return log_warning_errno(errno, "Failed to read /dev/mqueue: %m");
+}
+
+int clean_ipc(uid_t uid) {
+ int ret = 0, r;
+
+ /* Refuse to clean IPC of the root and system users */
+ if (uid <= SYSTEM_UID_MAX)
+ return 0;
+
+ r = clean_sysvipc_shm(uid);
+ if (r < 0)
+ ret = r;
+
+ r = clean_sysvipc_sem(uid);
+ if (r < 0)
+ ret = r;
+
+ r = clean_sysvipc_msg(uid);
+ if (r < 0)
+ ret = r;
+
+ r = clean_posix_shm(uid);
+ if (r < 0)
+ ret = r;
+
+ r = clean_posix_mq(uid);
+ if (r < 0)
+ ret = r;
+
+ return ret;
+}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-07-06 01:55:07 +0000