diff options
Diffstat (limited to 'src/libshared/clean-ipc.c')
| -rw-r--r-- | src/libshared/clean-ipc.c | 365 |
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; +} |