X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fjournal%2Fcoredump.c;h=4d9ef1c7ee2a39e7b7a9f8df9798842c58d03940;hp=c989be9b82e96a1607260bff07b036e5eb7e9bd1;hb=1eef15b181507f95dc41ec00a0eef5c0a7499351;hpb=9bdbc2e2ec523dbefe1c1c7e164b5544aff0b185 diff --git a/src/journal/coredump.c b/src/journal/coredump.c index c989be9b8..4d9ef1c7e 100644 --- a/src/journal/coredump.c +++ b/src/journal/coredump.c @@ -23,170 +23,472 @@ #include #include #include +#include +#include #include - -#ifdef HAVE_LOGIND #include -#endif #include "log.h" #include "util.h" +#include "strv.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" +#include "path-util.h" + +#ifdef HAVE_ACL +#include +#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)) -#define COREDUMP_MAX (24*1024*1024) +/* 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 + INFO_PID, + INFO_UID, + INFO_GID, + INFO_SIGNAL, + INFO_TIMESTAMP, + INFO_COMM, + INFO_EXE, + _INFO_LEN }; -static int divert_coredump(void) { - FILE *f; +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, const char *info[_INFO_LEN]) { + + static const char * const xattrs[_INFO_LEN] = { + [INFO_PID] = "user.coredump.pid", + [INFO_UID] = "user.coredump.uid", + [INFO_GID] = "user.coredump.gid", + [INFO_SIGNAL] = "user.coredump.signal", + [INFO_TIMESTAMP] = "user.coredump.timestamp", + [INFO_COMM] = "user.coredump.comm", + [INFO_EXE] = "user.coredump.exe", + }; + + int r = 0; + unsigned i; + + /* Attach some metadata to coredumps via extended + * attributes. Just because we can. */ + + for (i = 0; i < _INFO_LEN; i++) { + int k; + + if (isempty(info[i]) || !xattrs[i]) + continue; + + k = fsetxattr(fd, xattrs[i], info[i], strlen(info[i]), XATTR_CREATE); + if (k < 0 && r == 0) + r = -errno; + } + + return r; +} + +#define filename_escape(s) xescape((s), "./ ") + +static int save_external_coredump(const char *info[_INFO_LEN], + 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; - log_info("Detected coredump of the journal daemon itself, diverting coredump to /var/lib/systemd/coredump/."); + assert(info); + assert(ret_filename); + assert(ret_fd); + assert(ret_size); + + c = filename_escape(info[INFO_COMM]); + if (!c) + return log_oom(); + + p = filename_escape(info[INFO_PID]); + if (!p) + return log_oom(); + + t = filename_escape(info[INFO_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); - f = fopen("/var/lib/systemd/coredump/core.systemd-journald", "we"); - if (!f) { + 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; } - for (;;) { - uint8_t buffer[4096]; - size_t l, q; - - l = fread(buffer, 1, sizeof(buffer), stdin); - if (l <= 0) { - if (ferror(f)) { - log_error("Failed to read coredump: %m"); - r = -errno; - goto finish; - } + r = copy_bytes(STDIN_FILENO, fd, arg_process_size_max); + if (r == -E2BIG) { + log_error("Coredump of %s (%s) is larger than configured processing limit, refusing.", + info[INFO_PID], info[INFO_COMM]); + goto fail; + } else if (IN_SET(r, -EDQUOT, -ENOSPC)) { + log_error("Not enough disk space for coredump of %s (%s), refusing.", + info[INFO_PID], info[INFO_COMM]); + goto fail; + } else if (r < 0) { + log_error("Failed to dump coredump to file: %s", strerror(-r)); + goto fail; + } - r = 0; - break; - } + /* Ignore errors on these */ + fchmod(fd, 0640); + fix_acl(fd, uid); + fix_xattr(fd, info); - q = fwrite(buffer, 1, l, f); - if (q != l) { - log_error("Failed to write coredump: %m"); - r = -errno; - goto finish; - } + if (fsync(fd) < 0) { + log_error("Failed to sync coredump %s: %m", tmp); + r = -errno; + goto fail; } - fflush(f); + if (fstat(fd, &st) < 0) { + log_error("Failed to fstat coredump %s: %m", tmp); + r = -errno; + goto fail; + } - if (ferror(f)) { - log_error("Failed to write coredump: %m"); + if (rename(tmp, fn) < 0) { + log_error("Failed to rename coredump %s -> %s: %m", tmp, fn); r = -errno; + goto fail; } -finish: - fclose(f); + *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, *comm = NULL; + const char *info[_INFO_LEN]; + + _cleanup_close_ int coredump_fd = -1; + + struct iovec iovec[17]; + off_t coredump_size; int r, j = 0; - char *p = NULL; - ssize_t n; - pid_t pid; - uid_t uid; + uid_t uid, owner_uid; gid_t gid; - struct iovec iovec[14]; - 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, *t; + pid_t pid; + char *t; + /* Make sure we never enter a loop */ prctl(PR_SET_DUMPABLE, 0); - if (argc != _ARG_MAX) { - log_set_target(LOG_TARGET_JOURNAL_OR_KMSG); - log_open(); + /* 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(); - log_error("Invalid number of arguments passed from kernel."); + if (argc < INFO_COMM + 1) { + log_error("Not enough arguments passed from kernel (%d, expected %d).", + argc - 1, INFO_COMM + 1 - 1); r = -EINVAL; goto finish; } - r = parse_pid(argv[ARG_PID], &pid); + /* Ignore all parse errors */ + parse_config(); + log_debug("Selected storage '%s'.", coredump_storage_to_string(arg_storage)); + + /* Exit early if we cannot write the coredump to disk anyway */ + if (path_is_read_only_fs("/var/lib") != 0) { + log_error("Coredump directory not mounted or not writable, skipping coredump."); + r = -EROFS; + goto finish; + } + + r = parse_uid(argv[INFO_UID + 1], &uid); if (r < 0) { - log_set_target(LOG_TARGET_JOURNAL_OR_KMSG); - log_open(); + log_error("Failed to parse UID."); + goto finish; + } + r = parse_pid(argv[INFO_PID + 1], &pid); + if (r < 0) { log_error("Failed to parse PID."); goto finish; } + r = parse_gid(argv[INFO_GID + 1], &gid); + if (r < 0) { + log_error("Failed to parse GID."); + goto finish; + } + + if (get_process_comm(pid, &comm) < 0) { + log_warning("Failed to get COMM, falling back to the commandline."); + comm = strv_join(argv + INFO_COMM + 1, " "); + } + + if (get_process_exe(pid, &exe) < 0) + log_warning("Failed to get EXE."); + + info[INFO_PID] = argv[INFO_PID + 1]; + info[INFO_UID] = argv[INFO_UID + 1]; + info[INFO_GID] = argv[INFO_GID + 1]; + info[INFO_SIGNAL] = argv[INFO_SIGNAL + 1]; + info[INFO_TIMESTAMP] = argv[INFO_TIMESTAMP + 1]; + info[INFO_COMM] = comm; + info[INFO_EXE] = exe; + if (cg_pid_get_unit(pid, &t) >= 0) { if (streq(t, SPECIAL_JOURNALD_SERVICE)) { - /* Make sure we don't make use of the journal, - * if it's the journal which is crashing */ - log_set_target(LOG_TARGET_KMSG); - log_open(); - r = divert_coredump(); + /* 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(info, 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); - free(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); - } + if (core_unit) + IOVEC_SET_STRING(iovec[j++], core_unit); - /* OK, now we know it's not the journal, hence make use of - * it */ + /* 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(); - r = parse_uid(argv[ARG_UID], &uid); - if (r < 0) { - log_error("Failed to parse UID."); - goto finish; - } - - r = parse_gid(argv[ARG_GID], &gid); - if (r < 0) { - log_error("Failed to parse GID."); - goto finish; - } - - core_pid = strappend("COREDUMP_PID=", argv[ARG_PID]); + core_pid = strappend("COREDUMP_PID=", info[INFO_PID]); if (core_pid) IOVEC_SET_STRING(iovec[j++], core_pid); - core_uid = strappend("COREDUMP_UID=", argv[ARG_UID]); + core_uid = strappend("COREDUMP_UID=", info[INFO_UID]); if (core_uid) IOVEC_SET_STRING(iovec[j++], core_uid); - core_gid = strappend("COREDUMP_GID=", argv[ARG_GID]); + core_gid = strappend("COREDUMP_GID=", info[INFO_GID]); if (core_gid) IOVEC_SET_STRING(iovec[j++], core_gid); - core_signal = strappend("COREDUMP_SIGNAL=", argv[ARG_SIGNAL]); + core_signal = strappend("COREDUMP_SIGNAL=", info[INFO_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); - -#ifdef HAVE_LOGIND if (sd_pid_get_session(pid, &t) >= 0) { core_session = strappend("COREDUMP_SESSION=", t); free(t); @@ -195,12 +497,29 @@ int main(int argc, char* argv[]) { IOVEC_SET_STRING(iovec[j++], core_session); } -#endif + if (sd_pid_get_owner_uid(pid, &owner_uid) >= 0) { + asprintf(&core_owner_uid, "COREDUMP_OWNER_UID=" UID_FMT, owner_uid); - if (get_process_exe(pid, &t) >= 0) { - core_exe = strappend("COREDUMP_EXE=", t); + 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 (comm) { + core_comm = strappend("COREDUMP_COMM=", comm); + if (core_comm) + IOVEC_SET_STRING(iovec[j++], core_comm); + } + + if (exe) { + core_exe = strappend("COREDUMP_EXE=", exe); if (core_exe) IOVEC_SET_STRING(iovec[j++], core_exe); } @@ -213,23 +532,39 @@ int main(int argc, char* argv[]) { IOVEC_SET_STRING(iovec[j++], core_cmdline); } - core_timestamp = strjoin("COREDUMP_TIMESTAMP=", argv[ARG_TIMESTAMP], "000000", NULL); + 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=", info[INFO_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"); - core_message = strjoin("MESSAGE=Process ", argv[ARG_PID], " (", argv[ARG_COMM], ") dumped core.", NULL); - if (core_message) - IOVEC_SET_STRING(iovec[j++], core_message); + /* Always stream the coredump to disk, if that's possible */ + r = save_external_coredump(info, 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"); @@ -237,42 +572,43 @@ int main(int argc, char* argv[]) { goto finish; } - p = malloc(9 + COREDUMP_MAX); - if (!p) { - r = log_oom(); - 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 ", info[INFO_PID], " (", comm, ") of user ", info[INFO_UID], " dumped core.\n\n", stacktrace, NULL); + else + log_warning("Failed to generate stack trace: %s", strerror(-r)); } - memcpy(p, "COREDUMP=", 9); + if (!core_message) +#endif + core_message = strjoin("MESSAGE=Process ", info[INFO_PID], " (", comm, ") of user ", info[INFO_UID], " dumped core.", NULL); + if (core_message) + IOVEC_SET_STRING(iovec[j++], core_message); - n = loop_read(STDIN_FILENO, p + 9, COREDUMP_MAX, false); - if (n < 0) { - log_error("Failed to read core dump data: %s", strerror(-n)); - r = (int) n; - goto finish; - } + /* 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; - iovec[j].iov_base = p; - iovec[j].iov_len = 9 + n; - j++; + /* 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 send coredump: %s", strerror(-r)); + log_error("Failed to log coredump: %s", strerror(-r)); finish: - free(p); - free(core_pid); - free(core_uid); - free(core_gid); - free(core_signal); - free(core_timestamp); - free(core_comm); - free(core_exe); - free(core_cmdline); - free(core_unit); - free(core_session); - free(core_message); - return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS; }