/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include #include #include #include #include #if HAVE_ELFUTILS #include #include #endif #include "sd-daemon.h" #include "sd-journal.h" #include "sd-login.h" #include "sd-messages.h" #include "acl-util.h" #include "alloc-util.h" #include "capability-util.h" #include "cgroup-util.h" #include "compress.h" #include "conf-parser.h" #include "copy.h" #include "coredump-vacuum.h" #include "dirent-util.h" #include "escape.h" #include "fd-util.h" #include "fileio.h" #include "fs-util.h" #include "io-util.h" #include "journal-importer.h" #include "log.h" #include "macro.h" #include "main-func.h" #include "memory-util.h" #include "mkdir.h" #include "parse-util.h" #include "process-util.h" #include "signal-util.h" #include "socket-util.h" #include "special.h" #include "stacktrace.h" #include "string-table.h" #include "string-util.h" #include "strv.h" #include "tmpfile-util.h" #include "user-record.h" #include "user-util.h" /* The maximum size up to which we process coredumps */ #define PROCESS_SIZE_MAX ((uint64_t) (2LLU*1024LLU*1024LLU*1024LLU)) /* The maximum size up to which we leave the coredump around on disk */ #define EXTERNAL_SIZE_MAX PROCESS_SIZE_MAX /* The maximum size up to which we store the coredump in the journal */ #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION #define JOURNAL_SIZE_MAX ((size_t) (767LU*1024LU*1024LU)) #else /* oss-fuzz limits memory usage. */ #define JOURNAL_SIZE_MAX ((size_t) (10LU*1024LU*1024LU)) #endif /* Make sure to not make this larger than the maximum journal entry * size. See DATA_SIZE_MAX in journal-importer.h. */ assert_cc(JOURNAL_SIZE_MAX <= DATA_SIZE_MAX); enum { /* We use these as array indexes for our process metadata cache. * * The first indices of the cache stores the same metadata as the ones passed by * the kernel via argv[], ie the strings array passed by the kernel according to * our pattern defined in /proc/sys/kernel/core_pattern (see man:core(5)). */ META_ARGV_PID, /* %P: as seen in the initial pid namespace */ META_ARGV_UID, /* %u: as seen in the initial user namespace */ META_ARGV_GID, /* %g: as seen in the initial user namespace */ META_ARGV_SIGNAL, /* %s: number of signal causing dump */ META_ARGV_TIMESTAMP, /* %t: time of dump, expressed as seconds since the Epoch (we expand this to µs granularity) */ META_ARGV_RLIMIT, /* %c: core file size soft resource limit */ META_ARGV_HOSTNAME, /* %h: hostname */ _META_ARGV_MAX, /* The following indexes are cached for a couple of special fields we use (and * thereby need to be retrieved quickly) for naming coredump files, and attaching * xattrs. Unlike the previous ones they are retrieved from the runtime * environment. */ META_COMM = _META_ARGV_MAX, _META_MANDATORY_MAX, /* The rest are similar to the previous ones except that we won't fail if one of * them is missing. */ META_EXE = _META_MANDATORY_MAX, META_UNIT, _META_MAX }; static const char * const meta_field_names[_META_MAX] = { [META_ARGV_PID] = "COREDUMP_PID=", [META_ARGV_UID] = "COREDUMP_UID=", [META_ARGV_GID] = "COREDUMP_GID=", [META_ARGV_SIGNAL] = "COREDUMP_SIGNAL=", [META_ARGV_TIMESTAMP] = "COREDUMP_TIMESTAMP=", [META_ARGV_RLIMIT] = "COREDUMP_RLIMIT=", [META_ARGV_HOSTNAME] = "COREDUMP_HOSTNAME=", [META_COMM] = "COREDUMP_COMM=", [META_EXE] = "COREDUMP_EXE=", [META_UNIT] = "COREDUMP_UNIT=", }; typedef struct Context { const char *meta[_META_MAX]; pid_t pid; bool is_pid1; bool is_journald; } Context; typedef enum CoredumpStorage { COREDUMP_STORAGE_NONE, COREDUMP_STORAGE_EXTERNAL, COREDUMP_STORAGE_JOURNAL, _COREDUMP_STORAGE_MAX, _COREDUMP_STORAGE_INVALID = -1 } CoredumpStorage; static const char* const coredump_storage_table[_COREDUMP_STORAGE_MAX] = { [COREDUMP_STORAGE_NONE] = "none", [COREDUMP_STORAGE_EXTERNAL] = "external", [COREDUMP_STORAGE_JOURNAL] = "journal", }; DEFINE_PRIVATE_STRING_TABLE_LOOKUP(coredump_storage, CoredumpStorage); static DEFINE_CONFIG_PARSE_ENUM(config_parse_coredump_storage, coredump_storage, CoredumpStorage, "Failed to parse storage setting"); static CoredumpStorage arg_storage = COREDUMP_STORAGE_EXTERNAL; static bool arg_compress = true; static uint64_t arg_process_size_max = PROCESS_SIZE_MAX; static uint64_t arg_external_size_max = EXTERNAL_SIZE_MAX; static uint64_t arg_journal_size_max = JOURNAL_SIZE_MAX; static uint64_t arg_keep_free = (uint64_t) -1; static uint64_t arg_max_use = (uint64_t) -1; static int parse_config(void) { static const ConfigTableItem items[] = { { "Coredump", "Storage", config_parse_coredump_storage, 0, &arg_storage }, { "Coredump", "Compress", config_parse_bool, 0, &arg_compress }, { "Coredump", "ProcessSizeMax", config_parse_iec_uint64, 0, &arg_process_size_max }, { "Coredump", "ExternalSizeMax", config_parse_iec_uint64, 0, &arg_external_size_max }, { "Coredump", "JournalSizeMax", config_parse_iec_size, 0, &arg_journal_size_max }, { "Coredump", "KeepFree", config_parse_iec_uint64, 0, &arg_keep_free }, { "Coredump", "MaxUse", config_parse_iec_uint64, 0, &arg_max_use }, {} }; return config_parse_many_nulstr( PKGSYSCONFDIR "/coredump.conf", CONF_PATHS_NULSTR("systemd/coredump.conf.d"), "Coredump\0", config_item_table_lookup, items, CONFIG_PARSE_WARN, NULL, NULL); } static uint64_t storage_size_max(void) { if (arg_storage == COREDUMP_STORAGE_EXTERNAL) return arg_external_size_max; if (arg_storage == COREDUMP_STORAGE_JOURNAL) return arg_journal_size_max; assert(arg_storage == COREDUMP_STORAGE_NONE); return 0; } static int fix_acl(int fd, uid_t uid) { #if HAVE_ACL int r; assert(fd >= 0); assert(uid_is_valid(uid)); if (uid_is_system(uid) || uid_is_dynamic(uid) || uid == UID_NOBODY) return 0; /* Make sure normal users can read (but not write or delete) their own coredumps */ r = fd_add_uid_acl_permission(fd, uid, ACL_READ); if (r < 0) return log_error_errno(r, "Failed to adjust ACL of the coredump: %m"); #endif return 0; } static int fix_xattr(int fd, const Context *context) { static const char * const xattrs[_META_MAX] = { [META_ARGV_PID] = "user.coredump.pid", [META_ARGV_UID] = "user.coredump.uid", [META_ARGV_GID] = "user.coredump.gid", [META_ARGV_SIGNAL] = "user.coredump.signal", [META_ARGV_TIMESTAMP] = "user.coredump.timestamp", [META_ARGV_RLIMIT] = "user.coredump.rlimit", [META_ARGV_HOSTNAME] = "user.coredump.hostname", [META_COMM] = "user.coredump.comm", [META_EXE] = "user.coredump.exe", }; int r = 0; unsigned i; assert(fd >= 0); /* Attach some metadata to coredumps via extended * attributes. Just because we can. */ for (i = 0; i < _META_MAX; i++) { int k; if (isempty(context->meta[i]) || !xattrs[i]) continue; k = fsetxattr(fd, xattrs[i], context->meta[i], strlen(context->meta[i]), XATTR_CREATE); if (k < 0 && r == 0) r = -errno; } return r; } #define filename_escape(s) xescape((s), "./ ") static const char *coredump_tmpfile_name(const char *s) { return s ? s : "(unnamed temporary file)"; } static int fix_permissions( int fd, const char *filename, const char *target, const Context *context, uid_t uid) { int r; assert(fd >= 0); assert(target); assert(context); /* Ignore errors on these */ (void) fchmod(fd, 0640); (void) fix_acl(fd, uid); (void) fix_xattr(fd, context); if (fsync(fd) < 0) return log_error_errno(errno, "Failed to sync coredump %s: %m", coredump_tmpfile_name(filename)); (void) fsync_directory_of_file(fd); r = link_tmpfile(fd, filename, target); if (r < 0) return log_error_errno(r, "Failed to move coredump %s into place: %m", target); return 0; } static int maybe_remove_external_coredump(const char *filename, uint64_t size) { /* Returns 1 if might remove, 0 if will not remove, < 0 on error. */ if (arg_storage == COREDUMP_STORAGE_EXTERNAL && size <= arg_external_size_max) return 0; if (!filename) return 1; if (unlink(filename) < 0 && errno != ENOENT) return log_error_errno(errno, "Failed to unlink %s: %m", filename); return 1; } static int make_filename(const Context *context, char **ret) { _cleanup_free_ char *c = NULL, *u = NULL, *p = NULL, *t = NULL; sd_id128_t boot = {}; int r; assert(context); c = filename_escape(context->meta[META_COMM]); if (!c) return -ENOMEM; u = filename_escape(context->meta[META_ARGV_UID]); if (!u) return -ENOMEM; r = sd_id128_get_boot(&boot); if (r < 0) return r; p = filename_escape(context->meta[META_ARGV_PID]); if (!p) return -ENOMEM; t = filename_escape(context->meta[META_ARGV_TIMESTAMP]); if (!t) return -ENOMEM; if (asprintf(ret, "/var/lib/systemd/coredump/core.%s.%s." SD_ID128_FORMAT_STR ".%s.%s", c, u, SD_ID128_FORMAT_VAL(boot), p, t) < 0) return -ENOMEM; return 0; } static int save_external_coredump( const Context *context, int input_fd, char **ret_filename, int *ret_node_fd, int *ret_data_fd, uint64_t *ret_size, bool *ret_truncated) { _cleanup_free_ char *fn = NULL, *tmp = NULL; _cleanup_close_ int fd = -1; uint64_t rlimit, process_limit, max_size; struct stat st; uid_t uid; int r; assert(context); assert(ret_filename); assert(ret_node_fd); assert(ret_data_fd); assert(ret_size); r = parse_uid(context->meta[META_ARGV_UID], &uid); if (r < 0) return log_error_errno(r, "Failed to parse UID: %m"); r = safe_atou64(context->meta[META_ARGV_RLIMIT], &rlimit); if (r < 0) return log_error_errno(r, "Failed to parse resource limit '%s': %m", context->meta[META_ARGV_RLIMIT]); if (rlimit < page_size()) /* Is coredumping disabled? Then don't bother saving/processing the * coredump. Anything below PAGE_SIZE cannot give a readable coredump * (the kernel uses ELF_EXEC_PAGESIZE which is not easily accessible, but * is usually the same as PAGE_SIZE. */ return log_info_errno(SYNTHETIC_ERRNO(EBADSLT), "Resource limits disable core dumping for process %s (%s).", context->meta[META_ARGV_PID], context->meta[META_COMM]); process_limit = MAX(arg_process_size_max, storage_size_max()); if (process_limit == 0) return log_debug_errno(SYNTHETIC_ERRNO(EBADSLT), "Limits for coredump processing and storage are both 0, not dumping core."); /* Never store more than the process configured, or than we actually shall keep or process */ max_size = MIN(rlimit, process_limit); r = make_filename(context, &fn); if (r < 0) return log_error_errno(r, "Failed to determine coredump file name: %m"); (void) mkdir_p_label("/var/lib/systemd/coredump", 0755); fd = open_tmpfile_linkable(fn, O_RDWR|O_CLOEXEC, &tmp); if (fd < 0) return log_error_errno(fd, "Failed to create temporary file for coredump %s: %m", fn); r = copy_bytes(input_fd, fd, max_size, 0); if (r < 0) { log_error_errno(r, "Cannot store coredump of %s (%s): %m", context->meta[META_ARGV_PID], context->meta[META_COMM]); goto fail; } *ret_truncated = r == 1; if (*ret_truncated) log_struct(LOG_INFO, LOG_MESSAGE("Core file was truncated to %zu bytes.", max_size), "SIZE_LIMIT=%zu", max_size, "MESSAGE_ID=" SD_MESSAGE_TRUNCATED_CORE_STR); if (fstat(fd, &st) < 0) { log_error_errno(errno, "Failed to fstat core file %s: %m", coredump_tmpfile_name(tmp)); goto fail; } if (lseek(fd, 0, SEEK_SET) == (off_t) -1) { log_error_errno(errno, "Failed to seek on %s: %m", coredump_tmpfile_name(tmp)); goto fail; } #if HAVE_COMPRESSION /* If we will remove the coredump anyway, do not compress. */ if (arg_compress && !maybe_remove_external_coredump(NULL, st.st_size)) { _cleanup_free_ char *fn_compressed = NULL, *tmp_compressed = NULL; _cleanup_close_ int fd_compressed = -1; fn_compressed = strjoin(fn, COMPRESSED_EXT); if (!fn_compressed) { log_oom(); goto uncompressed; } fd_compressed = open_tmpfile_linkable(fn_compressed, O_RDWR|O_CLOEXEC, &tmp_compressed); if (fd_compressed < 0) { log_error_errno(fd_compressed, "Failed to create temporary file for coredump %s: %m", fn_compressed); goto uncompressed; } r = compress_stream(fd, fd_compressed, -1); if (r < 0) { log_error_errno(r, "Failed to compress %s: %m", coredump_tmpfile_name(tmp_compressed)); goto fail_compressed; } r = fix_permissions(fd_compressed, tmp_compressed, fn_compressed, context, uid); if (r < 0) goto fail_compressed; /* OK, this worked, we can get rid of the uncompressed version now */ if (tmp) unlink_noerrno(tmp); *ret_filename = TAKE_PTR(fn_compressed); /* compressed */ *ret_node_fd = TAKE_FD(fd_compressed); /* compressed */ *ret_data_fd = TAKE_FD(fd); /* uncompressed */ *ret_size = (uint64_t) st.st_size; /* uncompressed */ return 0; fail_compressed: if (tmp_compressed) (void) unlink(tmp_compressed); } uncompressed: #endif r = fix_permissions(fd, tmp, fn, context, uid); if (r < 0) goto fail; *ret_filename = TAKE_PTR(fn); *ret_data_fd = TAKE_FD(fd); *ret_node_fd = -1; *ret_size = (uint64_t) st.st_size; return 0; fail: if (tmp) (void) unlink(tmp); return r; } static int allocate_journal_field(int fd, size_t size, char **ret, size_t *ret_size) { _cleanup_free_ char *field = NULL; ssize_t n; assert(fd >= 0); assert(ret); assert(ret_size); if (lseek(fd, 0, SEEK_SET) == (off_t) -1) return log_warning_errno(errno, "Failed to seek: %m"); field = malloc(9 + size); if (!field) { log_warning("Failed to allocate memory for coredump, coredump will not be stored."); return -ENOMEM; } memcpy(field, "COREDUMP=", 9); n = read(fd, field + 9, size); if (n < 0) return log_error_errno((int) n, "Failed to read core data: %m"); if ((size_t) n < size) return log_error_errno(SYNTHETIC_ERRNO(EIO), "Core data too short."); *ret = TAKE_PTR(field); *ret_size = size + 9; return 0; } /* Joins /proc/[pid]/fd/ and /proc/[pid]/fdinfo/ into the following lines: * 0:/dev/pts/23 * pos: 0 * flags: 0100002 * * 1:/dev/pts/23 * pos: 0 * flags: 0100002 * * 2:/dev/pts/23 * pos: 0 * flags: 0100002 * EOF */ static int compose_open_fds(pid_t pid, char **open_fds) { _cleanup_closedir_ DIR *proc_fd_dir = NULL; _cleanup_close_ int proc_fdinfo_fd = -1; _cleanup_free_ char *buffer = NULL; _cleanup_fclose_ FILE *stream = NULL; const char *fddelim = "", *path; struct dirent *dent = NULL; size_t size = 0; int r; assert(pid >= 0); assert(open_fds != NULL); path = procfs_file_alloca(pid, "fd"); proc_fd_dir = opendir(path); if (!proc_fd_dir) return -errno; proc_fdinfo_fd = openat(dirfd(proc_fd_dir), "../fdinfo", O_DIRECTORY|O_NOFOLLOW|O_CLOEXEC|O_PATH); if (proc_fdinfo_fd < 0) return -errno; stream = open_memstream_unlocked(&buffer, &size); if (!stream) return -ENOMEM; FOREACH_DIRENT(dent, proc_fd_dir, return -errno) { _cleanup_fclose_ FILE *fdinfo = NULL; _cleanup_free_ char *fdname = NULL; _cleanup_close_ int fd = -1; r = readlinkat_malloc(dirfd(proc_fd_dir), dent->d_name, &fdname); if (r < 0) return r; fprintf(stream, "%s%s:%s\n", fddelim, dent->d_name, fdname); fddelim = "\n"; /* Use the directory entry from /proc/[pid]/fd with /proc/[pid]/fdinfo */ fd = openat(proc_fdinfo_fd, dent->d_name, O_NOFOLLOW|O_CLOEXEC|O_RDONLY); if (fd < 0) continue; fdinfo = take_fdopen(&fd, "r"); if (!fdinfo) continue; for (;;) { _cleanup_free_ char *line = NULL; r = read_line(fdinfo, LONG_LINE_MAX, &line); if (r < 0) return r; if (r == 0) break; fputs(line, stream); fputc('\n', stream); } } errno = 0; stream = safe_fclose(stream); if (errno > 0) return -errno; *open_fds = TAKE_PTR(buffer); return 0; } static int get_process_ns(pid_t pid, const char *namespace, ino_t *ns) { const char *p; struct stat stbuf; _cleanup_close_ int proc_ns_dir_fd; p = procfs_file_alloca(pid, "ns"); proc_ns_dir_fd = open(p, O_DIRECTORY | O_CLOEXEC | O_RDONLY); if (proc_ns_dir_fd < 0) return -errno; if (fstatat(proc_ns_dir_fd, namespace, &stbuf, /* flags */0) < 0) return -errno; *ns = stbuf.st_ino; return 0; } static int get_mount_namespace_leader(pid_t pid, pid_t *container_pid) { pid_t cpid = pid, ppid = 0; ino_t proc_mntns; int r; r = get_process_ns(pid, "mnt", &proc_mntns); if (r < 0) return r; for (;;) { ino_t parent_mntns; r = get_process_ppid(cpid, &ppid); if (r < 0) return r; r = get_process_ns(ppid, "mnt", &parent_mntns); if (r < 0) return r; if (proc_mntns != parent_mntns) break; if (ppid == 1) return -ENOENT; cpid = ppid; } *container_pid = ppid; return 0; } /* Returns 1 if the parent was found. * Returns 0 if there is not a process we can call the pid's * container parent (the pid's process isn't 'containerized'). * Returns a negative number on errors. */ static int get_process_container_parent_cmdline(pid_t pid, char** cmdline) { int r = 0; pid_t container_pid; const char *proc_root_path; struct stat root_stat, proc_root_stat; /* To compare inodes of / and /proc/[pid]/root */ if (stat("/", &root_stat) < 0) return -errno; proc_root_path = procfs_file_alloca(pid, "root"); if (stat(proc_root_path, &proc_root_stat) < 0) return -errno; /* The process uses system root. */ if (proc_root_stat.st_ino == root_stat.st_ino) { *cmdline = NULL; return 0; } r = get_mount_namespace_leader(pid, &container_pid); if (r < 0) return r; r = get_process_cmdline(container_pid, SIZE_MAX, 0, cmdline); if (r < 0) return r; return 1; } static int change_uid_gid(const Context *context) { uid_t uid; gid_t gid; int r; r = parse_uid(context->meta[META_ARGV_UID], &uid); if (r < 0) return r; if (uid_is_system(uid)) { const char *user = "systemd-coredump"; r = get_user_creds(&user, &uid, &gid, NULL, NULL, 0); if (r < 0) { log_warning_errno(r, "Cannot resolve %s user. Proceeding to dump core as root: %m", user); uid = gid = 0; } } else { r = parse_gid(context->meta[META_ARGV_GID], &gid); if (r < 0) return r; } return drop_privileges(uid, gid, 0); } static int submit_coredump( Context *context, struct iovec_wrapper *iovw, int input_fd) { _cleanup_close_ int coredump_fd = -1, coredump_node_fd = -1; _cleanup_free_ char *filename = NULL, *coredump_data = NULL; _cleanup_free_ char *stacktrace = NULL; char *core_message; uint64_t coredump_size = UINT64_MAX; bool truncated = false; int r; assert(context); assert(iovw); assert(input_fd >= 0); /* Vacuum before we write anything again */ (void) coredump_vacuum(-1, arg_keep_free, arg_max_use); /* Always stream the coredump to disk, if that's possible */ r = save_external_coredump(context, input_fd, &filename, &coredump_node_fd, &coredump_fd, &coredump_size, &truncated); if (r < 0) /* Skip whole core dumping part */ goto log; /* If we don't want to keep the coredump on disk, remove it now, as later on we * will lack the privileges for it. However, we keep the fd to it, so that we can * still process it and log it. */ r = maybe_remove_external_coredump(filename, coredump_size); if (r < 0) return r; if (r == 0) { (void) iovw_put_string_field(iovw, "COREDUMP_FILENAME=", filename); } else if (arg_storage == COREDUMP_STORAGE_EXTERNAL) log_info("The core will not be stored: size %"PRIu64" is greater than %"PRIu64" (the configured maximum)", coredump_size, arg_external_size_max); /* Vacuum again, but exclude the coredump we just created */ (void) coredump_vacuum(coredump_node_fd >= 0 ? coredump_node_fd : coredump_fd, arg_keep_free, arg_max_use); /* Now, let's drop privileges to become the user who owns the segfaulted process * and allocate the coredump memory under the user's uid. This also ensures that * the credentials journald will see are the ones of the coredumping user, thus * making sure the user gets access to the core dump. Let's also get rid of all * capabilities, if we run as root, we won't need them anymore. */ r = change_uid_gid(context); if (r < 0) return log_error_errno(r, "Failed to drop privileges: %m"); #if HAVE_ELFUTILS /* Try to get a stack trace if we can */ if (coredump_size > arg_process_size_max) { log_debug("Not generating stack trace: core size %"PRIu64" is greater " "than %"PRIu64" (the configured maximum)", coredump_size, arg_process_size_max); } else coredump_make_stack_trace(coredump_fd, context->meta[META_EXE], &stacktrace); #endif log: core_message = strjoina("Process ", context->meta[META_ARGV_PID], " (", context->meta[META_COMM], ") of user ", context->meta[META_ARGV_UID], " dumped core.", context->is_journald && filename ? "\nCoredump diverted to " : NULL, context->is_journald && filename ? filename : NULL); core_message = strjoina(core_message, stacktrace ? "\n\n" : NULL, stacktrace); if (context->is_journald) { /* We cannot log to the journal, so just print the message. * The target was set previously to something safe. */ log_dispatch(LOG_ERR, 0, core_message); return 0; } (void) iovw_put_string_field(iovw, "MESSAGE=", core_message); if (truncated) (void) iovw_put_string_field(iovw, "COREDUMP_TRUNCATED=", "1"); /* Optionally store the entire coredump in the journal */ if (arg_storage == COREDUMP_STORAGE_JOURNAL) { if (coredump_size <= arg_journal_size_max) { size_t sz = 0; /* Store the coredump itself in the journal */ r = allocate_journal_field(coredump_fd, (size_t) coredump_size, &coredump_data, &sz); if (r >= 0) { if (iovw_put(iovw, coredump_data, sz) >= 0) TAKE_PTR(coredump_data); } else log_warning_errno(r, "Failed to attach the core to the journal entry: %m"); } else log_info("The core will not be stored: size %"PRIu64" is greater than %"PRIu64" (the configured maximum)", coredump_size, arg_journal_size_max); } r = sd_journal_sendv(iovw->iovec, iovw->count); if (r < 0) return log_error_errno(r, "Failed to log coredump: %m"); return 0; } static int save_context(Context *context, const struct iovec_wrapper *iovw) { unsigned n, i, count = 0; const char *unit; int r; assert(context); assert(iovw); assert(iovw->count >= _META_ARGV_MAX); /* The context does not allocate any memory on its own */ for (n = 0; n < iovw->count; n++) { struct iovec *iovec = iovw->iovec + n; for (i = 0; i < ELEMENTSOF(meta_field_names); i++) { char *p; /* Note that these strings are NUL terminated, because we made sure that a * trailing NUL byte is in the buffer, though not included in the iov_len * count (see process_socket() and gather_pid_metadata_*()) */ assert(((char*) iovec->iov_base)[iovec->iov_len] == 0); p = startswith(iovec->iov_base, meta_field_names[i]); if (p) { context->meta[i] = p; count++; break; } } } if (!context->meta[META_ARGV_PID]) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to find the PID of crashing process"); r = parse_pid(context->meta[META_ARGV_PID], &context->pid); if (r < 0) return log_error_errno(r, "Failed to parse PID \"%s\": %m", context->meta[META_ARGV_PID]); unit = context->meta[META_UNIT]; context->is_pid1 = streq(context->meta[META_ARGV_PID], "1") || streq_ptr(unit, SPECIAL_INIT_SCOPE); context->is_journald = streq_ptr(unit, SPECIAL_JOURNALD_SERVICE); return 0; } static int process_socket(int fd) { _cleanup_close_ int input_fd = -1; Context context = {}; struct iovec_wrapper iovw = {}; struct iovec iovec; int i, r; assert(fd >= 0); log_setup_service(); log_debug("Processing coredump received on stdin..."); for (;;) { CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int))) control; struct msghdr mh = { .msg_control = &control, .msg_controllen = sizeof(control), .msg_iovlen = 1, }; ssize_t n; ssize_t l; l = next_datagram_size_fd(fd); if (l < 0) { r = log_error_errno(l, "Failed to determine datagram size to read: %m"); goto finish; } iovec.iov_len = l; iovec.iov_base = malloc(l + 1); if (!iovec.iov_base) { r = log_oom(); goto finish; } mh.msg_iov = &iovec; n = recvmsg_safe(fd, &mh, MSG_CMSG_CLOEXEC); if (n < 0) { free(iovec.iov_base); r = log_error_errno(n, "Failed to receive datagram: %m"); goto finish; } /* The final zero-length datagram carries the file descriptor and tells us * that we're done. */ if (n == 0) { struct cmsghdr *found; free(iovec.iov_base); found = cmsg_find(&mh, SOL_SOCKET, SCM_RIGHTS, CMSG_LEN(sizeof(int))); if (!found) { cmsg_close_all(&mh); r = log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Coredump file descriptor missing."); goto finish; } assert(input_fd < 0); input_fd = *(int*) CMSG_DATA(found); break; } else cmsg_close_all(&mh); /* Add trailing NUL byte, in case these are strings */ ((char*) iovec.iov_base)[n] = 0; iovec.iov_len = (size_t) n; r = iovw_put(&iovw, iovec.iov_base, iovec.iov_len); if (r < 0) goto finish; } /* Make sure we got all data we really need */ assert(input_fd >= 0); r = save_context(&context, &iovw); if (r < 0) goto finish; /* Make sure we received at least all fields we need. */ for (i = 0; i < _META_MANDATORY_MAX; i++) if (!context.meta[i]) { r = log_error_errno(SYNTHETIC_ERRNO(EINVAL), "A mandatory argument (%i) has not been sent, aborting.", i); goto finish; } r = submit_coredump(&context, &iovw, input_fd); finish: iovw_free_contents(&iovw, true); return r; } static int send_iovec(const struct iovec_wrapper *iovw, int input_fd) { static const union sockaddr_union sa = { .un.sun_family = AF_UNIX, .un.sun_path = "/run/systemd/coredump", }; _cleanup_close_ int fd = -1; size_t i; int r; assert(iovw); assert(input_fd >= 0); fd = socket(AF_UNIX, SOCK_SEQPACKET|SOCK_CLOEXEC, 0); if (fd < 0) return log_error_errno(errno, "Failed to create coredump socket: %m"); if (connect(fd, &sa.sa, SOCKADDR_UN_LEN(sa.un)) < 0) return log_error_errno(errno, "Failed to connect to coredump service: %m"); for (i = 0; i < iovw->count; i++) { struct msghdr mh = { .msg_iov = iovw->iovec + i, .msg_iovlen = 1, }; struct iovec copy[2]; for (;;) { if (sendmsg(fd, &mh, MSG_NOSIGNAL) >= 0) break; if (errno == EMSGSIZE && mh.msg_iov[0].iov_len > 0) { /* This field didn't fit? That's a pity. Given that this is * just metadata, let's truncate the field at half, and try * again. We append three dots, in order to show that this is * truncated. */ if (mh.msg_iov != copy) { /* We don't want to modify the caller's iovec, hence * let's create our own array, consisting of two new * iovecs, where the first is a (truncated) copy of * what we want to send, and the second one contains * the trailing dots. */ copy[0] = iovw->iovec[i]; copy[1] = IOVEC_MAKE(((char[]){'.', '.', '.'}), 3); mh.msg_iov = copy; mh.msg_iovlen = 2; } copy[0].iov_len /= 2; /* halve it, and try again */ continue; } return log_error_errno(errno, "Failed to send coredump datagram: %m"); } } r = send_one_fd(fd, input_fd, 0); if (r < 0) return log_error_errno(r, "Failed to send coredump fd: %m"); return 0; } static int gather_pid_metadata_from_argv( struct iovec_wrapper *iovw, Context *context, int argc, char **argv) { _cleanup_free_ char *free_timestamp = NULL; int i, r, signo; char *t; /* We gather all metadata that were passed via argv[] into an array of iovecs that * we'll forward to the socket unit */ if (argc < _META_ARGV_MAX) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Not enough arguments passed by the kernel (%i, expected %i).", argc, _META_ARGV_MAX); for (i = 0; i < _META_ARGV_MAX; i++) { t = argv[i]; switch (i) { case META_ARGV_TIMESTAMP: /* The journal fields contain the timestamp padded with six * zeroes, so that the kernel-supplied 1s granularity timestamps * becomes 1µs granularity, i.e. the granularity systemd usually * operates in. */ t = free_timestamp = strjoin(argv[i], "000000"); if (!t) return log_oom(); break; case META_ARGV_SIGNAL: /* For signal, record its pretty name too */ if (safe_atoi(argv[i], &signo) >= 0 && SIGNAL_VALID(signo)) (void) iovw_put_string_field(iovw, "COREDUMP_SIGNAL_NAME=SIG", signal_to_string(signo)); break; default: break; } r = iovw_put_string_field(iovw, meta_field_names[i], t); if (r < 0) return r; } /* Cache some of the process metadata we collected so far and that we'll need to * access soon */ return save_context(context, iovw); } static int gather_pid_metadata(struct iovec_wrapper *iovw, Context *context) { uid_t owner_uid; pid_t pid; char *t; const char *p; int r; /* Note that if we fail on oom later on, we do not roll-back changes to the iovec * structure. (It remains valid, with the first iovec fields initialized.) */ pid = context->pid; /* The following is mandatory */ r = get_process_comm(pid, &t); if (r < 0) return log_error_errno(r, "Failed to get COMM: %m"); r = iovw_put_string_field_free(iovw, "COREDUMP_COMM=", t); if (r < 0) return r; /* The following are optional but we used them if present */ r = get_process_exe(pid, &t); if (r >= 0) r = iovw_put_string_field_free(iovw, "COREDUMP_EXE=", t); if (r < 0) log_warning_errno(r, "Failed to get EXE, ignoring: %m"); if (cg_pid_get_unit(pid, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_UNIT=", t); /* The next are optional */ if (cg_pid_get_user_unit(pid, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_USER_UNIT=", t); if (sd_pid_get_session(pid, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_SESSION=", t); if (sd_pid_get_owner_uid(pid, &owner_uid) >= 0) { r = asprintf(&t, UID_FMT, owner_uid); if (r > 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_OWNER_UID=", t); } if (sd_pid_get_slice(pid, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_SLICE=", t); if (get_process_cmdline(pid, SIZE_MAX, 0, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_CMDLINE=", t); if (cg_pid_get_path_shifted(pid, NULL, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_CGROUP=", t); if (compose_open_fds(pid, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_OPEN_FDS=", t); p = procfs_file_alloca(pid, "status"); if (read_full_file(p, &t, NULL) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_PROC_STATUS=", t); p = procfs_file_alloca(pid, "maps"); if (read_full_file(p, &t, NULL) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_PROC_MAPS=", t); p = procfs_file_alloca(pid, "limits"); if (read_full_file(p, &t, NULL) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_PROC_LIMITS=", t); p = procfs_file_alloca(pid, "cgroup"); if (read_full_file(p, &t, NULL) >=0) (void) iovw_put_string_field_free(iovw, "COREDUMP_PROC_CGROUP=", t); p = procfs_file_alloca(pid, "mountinfo"); if (read_full_file(p, &t, NULL) >=0) (void) iovw_put_string_field_free(iovw, "COREDUMP_PROC_MOUNTINFO=", t); if (get_process_cwd(pid, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_CWD=", t); if (get_process_root(pid, &t) >= 0) { bool proc_self_root_is_slash; proc_self_root_is_slash = strcmp(t, "/") == 0; (void) iovw_put_string_field_free(iovw, "COREDUMP_ROOT=", t); /* If the process' root is "/", then there is a chance it has * mounted own root and hence being containerized. */ if (proc_self_root_is_slash && get_process_container_parent_cmdline(pid, &t) > 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_CONTAINER_CMDLINE=", t); } if (get_process_environ(pid, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_ENVIRON=", t); /* we successfully acquired all metadata */ return save_context(context, iovw); } static int process_kernel(int argc, char* argv[]) { Context context = {}; struct iovec_wrapper *iovw; int r; log_debug("Processing coredump received from the kernel..."); iovw = iovw_new(); if (!iovw) return log_oom(); (void) iovw_put_string_field(iovw, "MESSAGE_ID=", SD_MESSAGE_COREDUMP_STR); (void) iovw_put_string_field(iovw, "PRIORITY=", STRINGIFY(LOG_CRIT)); /* Collect all process metadata passed by the kernel through argv[] */ r = gather_pid_metadata_from_argv(iovw, &context, argc - 1, argv + 1); if (r < 0) goto finish; /* Collect the rest of the process metadata retrieved from the runtime */ r = gather_pid_metadata(iovw, &context); if (r < 0) goto finish; if (!context.is_journald) { /* OK, now we know it's not the journal, hence we can make use of it now. */ log_set_target(LOG_TARGET_JOURNAL_OR_KMSG); log_open(); } /* If this is PID 1 disable coredump collection, we'll unlikely be able to process * it later on. * * FIXME: maybe we should disable coredumps generation from the beginning and * re-enable it only when we know it's either safe (ie we're not running OOM) or * it's not pid1 ? */ if (context.is_pid1) { log_notice("Due to PID 1 having crashed coredump collection will now be turned off."); disable_coredumps(); } if (context.is_journald || context.is_pid1) r = submit_coredump(&context, iovw, STDIN_FILENO); else r = send_iovec(iovw, STDIN_FILENO); finish: iovw = iovw_free_free(iovw); return r; } static int process_backtrace(int argc, char *argv[]) { Context context = {}; struct iovec_wrapper *iovw; char *message; size_t i; int r; _cleanup_(journal_importer_cleanup) JournalImporter importer = JOURNAL_IMPORTER_INIT(STDIN_FILENO); log_debug("Processing backtrace on stdin..."); iovw = iovw_new(); if (!iovw) return log_oom(); (void) iovw_put_string_field(iovw, "MESSAGE_ID=", SD_MESSAGE_BACKTRACE_STR); (void) iovw_put_string_field(iovw, "PRIORITY=", STRINGIFY(LOG_CRIT)); /* Collect all process metadata from argv[] by making sure to skip the * '--backtrace' option */ r = gather_pid_metadata_from_argv(iovw, &context, argc - 2, argv + 2); if (r < 0) goto finish; /* Collect the rest of the process metadata retrieved from the runtime */ r = gather_pid_metadata(iovw, &context); if (r < 0) goto finish; for (;;) { r = journal_importer_process_data(&importer); if (r < 0) { log_error_errno(r, "Failed to parse journal entry on stdin: %m"); goto finish; } if (r == 1 || /* complete entry */ journal_importer_eof(&importer)) /* end of data */ break; } if (journal_importer_eof(&importer)) { log_warning("Did not receive a full journal entry on stdin, ignoring message sent by reporter"); message = strjoina("Process ", context.meta[META_ARGV_PID], " (", context.meta[META_COMM], ")" " of user ", context.meta[META_ARGV_UID], " failed with ", context.meta[META_ARGV_SIGNAL]); r = iovw_put_string_field(iovw, "MESSAGE=", message); if (r < 0) return r; } else { /* The imported iovecs are not supposed to be freed by us so let's store * them at the end of the array so we can skip them while freeing the * rest. */ for (i = 0; i < importer.iovw.count; i++) { struct iovec *iovec = importer.iovw.iovec + i; iovw_put(iovw, iovec->iov_base, iovec->iov_len); } } r = sd_journal_sendv(iovw->iovec, iovw->count); if (r < 0) log_error_errno(r, "Failed to log backtrace: %m"); finish: iovw->count -= importer.iovw.count; iovw = iovw_free_free(iovw); return r; } static int run(int argc, char *argv[]) { int r; /* First, log to a safe place, since we don't know what crashed and it might * be journald which we'd rather not log to then. */ log_set_target(LOG_TARGET_KMSG); log_open(); /* Make sure we never enter a loop */ (void) prctl(PR_SET_DUMPABLE, 0); /* Ignore all parse errors */ (void) parse_config(); log_debug("Selected storage '%s'.", coredump_storage_to_string(arg_storage)); log_debug("Selected compression %s.", yes_no(arg_compress)); r = sd_listen_fds(false); if (r < 0) return log_error_errno(r, "Failed to determine the number of file descriptors: %m"); /* If we got an fd passed, we are running in coredumpd mode. Otherwise we * are invoked from the kernel as coredump handler. */ if (r == 0) { if (streq_ptr(argv[1], "--backtrace")) return process_backtrace(argc, argv); else return process_kernel(argc, argv); } else if (r == 1) return process_socket(SD_LISTEN_FDS_START); return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Received unexpected number of file descriptors."); } DEFINE_MAIN_FUNCTION(run);