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/* 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) {
struct dirent *de;
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;
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 (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);
}
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