diff options
Diffstat (limited to '')
-rw-r--r-- | src/shared/clean-ipc.c | 452 |
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); +} |