/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2012 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 <errno.h> #include <unistd.h> #include <stdio.h> #include <sys/prctl.h> #include <sys/types.h> #include <attr/xattr.h> #include <systemd/sd-journal.h> #include <systemd/sd-login.h> #include "log.h" #include "util.h" #include "macro.h" #include "mkdir.h" #include "special.h" #include "cgroup-util.h" #include "journald-native.h" #include "conf-parser.h" #include "copy.h" #include "stacktrace.h" #ifdef HAVE_ACL #include <sys/acl.h> #include "acl-util.h" #endif /* The maximum size up to which we process coredumps */ #define PROCESS_SIZE_MAX ((off_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 */ #define JOURNAL_SIZE_MAX ((size_t) (767LU*1024LU*1024LU)) /* Make sure to not make this larger than the maximum journal entry * size. See ENTRY_SIZE_MAX in journald-native.c. */ assert_cc(JOURNAL_SIZE_MAX <= ENTRY_SIZE_MAX); enum { ARG_PID = 1, ARG_UID, ARG_GID, ARG_SIGNAL, ARG_TIMESTAMP, ARG_COMM, _ARG_MAX }; typedef enum CoredumpStorage { COREDUMP_STORAGE_NONE, COREDUMP_STORAGE_EXTERNAL, COREDUMP_STORAGE_JOURNAL, COREDUMP_STORAGE_BOTH, _COREDUMP_STORAGE_MAX, _COREDUMP_STORAGE_INVALID = -1 } CoredumpStorage; static CoredumpStorage arg_storage = COREDUMP_STORAGE_EXTERNAL; static off_t arg_process_size_max = PROCESS_SIZE_MAX; static off_t arg_external_size_max = EXTERNAL_SIZE_MAX; static size_t arg_journal_size_max = JOURNAL_SIZE_MAX; static const char* const coredump_storage_table[_COREDUMP_STORAGE_MAX] = { [COREDUMP_STORAGE_NONE] = "none", [COREDUMP_STORAGE_EXTERNAL] = "external", [COREDUMP_STORAGE_JOURNAL] = "journal", [COREDUMP_STORAGE_BOTH] = "both", }; 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 int parse_config(void) { static const ConfigTableItem items[] = { { "Coredump", "ProcessSizeMax", config_parse_iec_off, 0, &arg_process_size_max }, { "Coredump", "ExternalSizeMax", config_parse_iec_off, 0, &arg_external_size_max }, { "Coredump", "JournalSizeMax", config_parse_iec_size, 0, &arg_journal_size_max }, { "Coredump", "Storage", config_parse_coredump_storage, 0, &arg_storage }, {} }; return config_parse( NULL, "/etc/systemd/coredump.conf", NULL, "Coredump\0", config_item_table_lookup, (void*) items, false, false, NULL); } static int fix_acl(int fd, uid_t uid) { #ifdef HAVE_ACL _cleanup_(acl_freep) acl_t acl = NULL; acl_entry_t entry; acl_permset_t permset; if (uid <= SYSTEM_UID_MAX) return 0; /* Make sure normal users can read (but not write or delete) * their own coredumps */ acl = acl_get_fd(fd); if (!acl) { log_error("Failed to get ACL: %m"); return -errno; } if (acl_create_entry(&acl, &entry) < 0 || acl_set_tag_type(entry, ACL_USER) < 0 || acl_set_qualifier(entry, &uid) < 0) { log_error("Failed to patch ACL: %m"); return -errno; } if (acl_get_permset(entry, &permset) < 0 || acl_add_perm(permset, ACL_READ) < 0 || calc_acl_mask_if_needed(&acl) < 0) { log_warning("Failed to patch ACL: %m"); return -errno; } if (acl_set_fd(fd, acl) < 0) { log_error("Failed to apply ACL: %m"); return -errno; } #endif return 0; } static int fix_xattr(int fd, char *argv[]) { static const char * const xattrs[_ARG_MAX] = { [ARG_PID] = "user.coredump.pid", [ARG_UID] = "user.coredump.uid", [ARG_GID] = "user.coredump.gid", [ARG_SIGNAL] = "user.coredump.signal", [ARG_TIMESTAMP] = "user.coredump.timestamp", [ARG_COMM] = "user.coredump.comm", }; int r = 0; unsigned i; /* Attach some metadate to coredumps via extended * attributes. Just because we can. */ for (i = 0; i < _ARG_MAX; i++) { if (isempty(argv[i])) continue; if (fsetxattr(fd, xattrs[i], argv[i], strlen(argv[i]), XATTR_CREATE) < 0) r = -errno; } return r; } #define filename_escape(s) xescape((s), "./") static int save_external_coredump(char **argv, uid_t uid, char **ret_filename, int *ret_fd, off_t *ret_size) { _cleanup_free_ char *p = NULL, *t = NULL, *c = NULL, *fn = NULL, *tmp = NULL; _cleanup_close_ int fd = -1; sd_id128_t boot; struct stat st; int r; assert(argv); assert(ret_filename); assert(ret_fd); assert(ret_size); c = filename_escape(argv[ARG_COMM]); if (!c) return log_oom(); p = filename_escape(argv[ARG_PID]); if (!p) return log_oom(); t = filename_escape(argv[ARG_TIMESTAMP]); if (!t) return log_oom(); r = sd_id128_get_boot(&boot); if (r < 0) { log_error("Failed to determine boot ID: %s", strerror(-r)); return r; } r = asprintf(&fn, "/var/lib/systemd/coredump/core.%s." SD_ID128_FORMAT_STR ".%s.%s000000", c, SD_ID128_FORMAT_VAL(boot), p, t); if (r < 0) return log_oom(); tmp = tempfn_random(fn); if (!tmp) return log_oom(); mkdir_p_label("/var/lib/systemd/coredump", 0755); fd = open(tmp, O_CREAT|O_EXCL|O_RDWR|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW, 0640); if (fd < 0) { log_error("Failed to create coredump file: %m"); return -errno; } r = copy_bytes(STDIN_FILENO, fd); if (r < 0) { log_error("Failed to dump coredump to file: %s", strerror(-r)); goto fail; } /* Ignore errors on these */ fchmod(fd, 0640); fix_acl(fd, uid); fix_xattr(fd, argv); if (fsync(fd) < 0) { log_error("Failed to sync coredump: %m"); r = -errno; goto fail; } if (fstat(fd, &st) < 0) { log_error("Failed to fstat coredump: %m"); r = -errno; goto fail; } if (rename(tmp, fn) < 0) { log_error("Failed to rename coredump: %m"); r = -errno; goto fail; } *ret_filename = fn; *ret_fd = fd; *ret_size = st.st_size; fn = NULL; fd = -1; return 0; fail: unlink_noerrno(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) { log_warning("Failed to seek: %m"); return -errno; } field = malloc(9 + size); if (!field) { log_warning("Failed to allocate memory fore coredump, coredump will not be stored."); return -ENOMEM; } memcpy(field, "COREDUMP=", 9); n = read(fd, field + 9, size); if (n < 0) { log_error("Failed to read core data: %s", strerror(-n)); return (int) n; } if ((size_t) n < size) { log_error("Core data too short."); return -EIO; } *ret = field; *ret_size = size + 9; field = NULL; return 0; } static int maybe_remove_external_coredump(const char *filename, off_t size) { if (!filename) return 0; if (IN_SET(arg_storage, COREDUMP_STORAGE_EXTERNAL, COREDUMP_STORAGE_BOTH) && size <= arg_external_size_max) return 0; if (unlink(filename) < 0) { log_error("Failed to unlink %s: %m", filename); return -errno; } return 0; } int main(int argc, char* argv[]) { _cleanup_free_ char *core_pid = NULL, *core_uid = NULL, *core_gid = NULL, *core_signal = NULL, *core_timestamp = NULL, *core_comm = NULL, *core_exe = NULL, *core_unit = NULL, *core_session = NULL, *core_message = NULL, *core_cmdline = NULL, *coredump_data = NULL, *coredump_filename = NULL, *core_slice = NULL, *core_cgroup = NULL, *core_owner_uid = NULL, *exe = NULL; _cleanup_close_ int coredump_fd = -1; struct iovec iovec[17]; off_t coredump_size; int r, j = 0; uid_t uid, owner_uid; gid_t gid; pid_t pid; char *t; /* Make sure we never enter a loop */ prctl(PR_SET_DUMPABLE, 0); /* 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(); if (argc != _ARG_MAX) { log_error("Invalid number of arguments passed from kernel."); r = -EINVAL; goto finish; } /* Ignore all parse errors */ parse_config(); log_debug("Selected storage '%s'.", coredump_storage_to_string(arg_storage)); r = parse_uid(argv[ARG_UID], &uid); if (r < 0) { log_error("Failed to parse UID."); goto finish; } r = parse_pid(argv[ARG_PID], &pid); if (r < 0) { log_error("Failed to parse PID."); goto finish; } r = parse_gid(argv[ARG_GID], &gid); if (r < 0) { log_error("Failed to parse GID."); goto finish; } if (cg_pid_get_unit(pid, &t) >= 0) { if (streq(t, SPECIAL_JOURNALD_SERVICE)) { /* If we are journald, we cut things short, * don't write to the journal, but still * create a coredump. */ if (arg_storage != COREDUMP_STORAGE_NONE) arg_storage = COREDUMP_STORAGE_EXTERNAL; r = save_external_coredump(argv, uid, &coredump_filename, &coredump_fd, &coredump_size); if (r < 0) goto finish; r = maybe_remove_external_coredump(coredump_filename, coredump_size); if (r < 0) goto finish; log_info("Detected coredump of the journal daemon itself, diverted to %s.", coredump_filename); goto finish; } core_unit = strappend("COREDUMP_UNIT=", t); } else if (cg_pid_get_user_unit(pid, &t) >= 0) core_unit = strappend("COREDUMP_USER_UNIT=", t); if (core_unit) IOVEC_SET_STRING(iovec[j++], core_unit); /* 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(); core_pid = strappend("COREDUMP_PID=", argv[ARG_PID]); if (core_pid) IOVEC_SET_STRING(iovec[j++], core_pid); core_uid = strappend("COREDUMP_UID=", argv[ARG_UID]); if (core_uid) IOVEC_SET_STRING(iovec[j++], core_uid); core_gid = strappend("COREDUMP_GID=", argv[ARG_GID]); if (core_gid) IOVEC_SET_STRING(iovec[j++], core_gid); core_signal = strappend("COREDUMP_SIGNAL=", argv[ARG_SIGNAL]); if (core_signal) IOVEC_SET_STRING(iovec[j++], core_signal); core_comm = strappend("COREDUMP_COMM=", argv[ARG_COMM]); if (core_comm) IOVEC_SET_STRING(iovec[j++], core_comm); if (sd_pid_get_session(pid, &t) >= 0) { core_session = strappend("COREDUMP_SESSION=", t); free(t); if (core_session) IOVEC_SET_STRING(iovec[j++], core_session); } if (sd_pid_get_owner_uid(pid, &owner_uid) >= 0) { asprintf(&core_owner_uid, "COREDUMP_OWNER_UID=" UID_FMT, owner_uid); if (core_owner_uid) IOVEC_SET_STRING(iovec[j++], core_owner_uid); } if (sd_pid_get_slice(pid, &t) >= 0) { core_slice = strappend("COREDUMP_SLICE=", t); free(t); if (core_slice) IOVEC_SET_STRING(iovec[j++], core_slice); } if (get_process_exe(pid, &exe) >= 0) { core_exe = strappend("COREDUMP_EXE=", exe); if (core_exe) IOVEC_SET_STRING(iovec[j++], core_exe); } if (get_process_cmdline(pid, 0, false, &t) >= 0) { core_cmdline = strappend("COREDUMP_CMDLINE=", t); free(t); if (core_cmdline) IOVEC_SET_STRING(iovec[j++], core_cmdline); } if (cg_pid_get_path_shifted(pid, NULL, &t) >= 0) { core_cgroup = strappend("COREDUMP_CGROUP=", t); free(t); if (core_cgroup) IOVEC_SET_STRING(iovec[j++], core_cgroup); } core_timestamp = strjoin("COREDUMP_TIMESTAMP=", argv[ARG_TIMESTAMP], "000000", NULL); if (core_timestamp) IOVEC_SET_STRING(iovec[j++], core_timestamp); IOVEC_SET_STRING(iovec[j++], "MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1"); IOVEC_SET_STRING(iovec[j++], "PRIORITY=2"); /* Always stream the coredump to disk, if that's possible */ r = save_external_coredump(argv, uid, &coredump_filename, &coredump_fd, &coredump_size); if (r < 0) goto finish; /* 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(coredump_filename, coredump_size); if (r < 0) goto finish; /* Now, let's drop privileges to become the user who owns the * segfaulted process and allocate the coredump memory under * his uid. This also ensures that the credentials journald * will see are the ones of the coredumping user, thus making * sure the user himself gets access to the core dump. */ if (setresgid(gid, gid, gid) < 0 || setresuid(uid, uid, uid) < 0) { log_error("Failed to drop privileges: %m"); r = -errno; goto finish; } #ifdef HAVE_ELFUTILS /* Try to get a strack trace if we can */ if (coredump_size <= arg_process_size_max) { _cleanup_free_ char *stacktrace = NULL; r = coredump_make_stack_trace(coredump_fd, exe, &stacktrace); if (r >= 0) core_message = strjoin("MESSAGE=Process ", argv[ARG_PID], " (", argv[ARG_COMM], ") of user ", argv[ARG_UID], " dumped core.\n\n", stacktrace, NULL); else log_warning("Failed to generate stack trace: %s", strerror(-r)); } if (!core_message) #endif core_message = strjoin("MESSAGE=Process ", argv[ARG_PID], " (", argv[ARG_COMM], ") of user ", argv[ARG_UID], " dumped core.", NULL); if (core_message) IOVEC_SET_STRING(iovec[j++], core_message); /* Optionally store the entire coredump in the journal */ if (IN_SET(arg_storage, COREDUMP_STORAGE_JOURNAL, COREDUMP_STORAGE_BOTH) && coredump_size <= (off_t) arg_journal_size_max) { size_t sz; /* Store the coredump itself in the journal */ r = allocate_journal_field(coredump_fd, (size_t) coredump_size, &coredump_data, &sz); if (r >= 0) { iovec[j].iov_base = coredump_data; iovec[j].iov_len = sz; j++; } } r = sd_journal_sendv(iovec, j); if (r < 0) log_error("Failed to log coredump: %s", strerror(-r)); finish: return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS; }