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/***
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 "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) {
_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 (!match_uid_gid(uid, gid, delete_uid, delete_gid))
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);
} else
log_debug("Removed SysV shared memory segment %i.", 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, gid_t delete_gid) {
_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 (!match_uid_gid(uid, gid, delete_uid, delete_gid))
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);
} else
log_debug("Removed SysV semaphore %i.", 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, gid_t delete_gid) {
_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 (!match_uid_gid(uid, gid, delete_uid, delete_gid))
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);
} else
log_debug("Removed SysV message queue %i.", 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, gid_t gid) {
struct dirent *de;
int ret = 0, r;
assert(dir);
FOREACH_DIRENT_ALL(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;
ret = log_warning_errno(errno, "Failed to stat() POSIX shared memory segment %s: %m", de->d_name);
continue;
}
if (!match_uid_gid(st.st_uid, st.st_gid, uid, gid))
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)
ret = log_warning_errno(errno, "Failed to enter shared memory directory %s: %m", de->d_name);
} else {
r = clean_posix_shm_internal(kid, uid, gid);
if (r < 0)
ret = r;
}
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: %m", de->d_name);
} else
log_debug("Removed POSIX shared memory directory %s", de->d_name);
} else {
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);
}
}
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) {
_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, gid);
}
static int clean_posix_mq(uid_t uid, gid_t gid) {
_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_ALL(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 (!match_uid_gid(st.st_uid, st.st_gid, uid, gid))
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);
} else
log_debug("Removed POSIX message queue %s", fn);
}
return ret;
fail:
return log_warning_errno(errno, "Failed to read /dev/mqueue: %m");
}
int clean_ipc(uid_t uid, gid_t gid) {
int ret = 0, r;
/* Anything to do? */
if (!uid_is_valid(uid) && !gid_is_valid(gid))
return 0;
/* Refuse to clean IPC of the root user */
if (uid == 0 && gid == 0)
return 0;
r = clean_sysvipc_shm(uid, gid);
if (r < 0)
ret = r;
r = clean_sysvipc_sem(uid, gid);
if (r < 0)
ret = r;
r = clean_sysvipc_msg(uid, gid);
if (r < 0)
ret = r;
r = clean_posix_shm(uid, gid);
if (r < 0)
ret = r;
r = clean_posix_mq(uid, gid);
if (r < 0)
ret = r;
return ret;
}
int clean_ipc_by_uid(uid_t uid) {
return clean_ipc(uid, GID_INVALID);
}
int clean_ipc_by_gid(gid_t gid) {
return clean_ipc(UID_INVALID, gid);
}
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