diff options
Diffstat (limited to 'src/coredump/coredump.c')
| -rw-r--r-- | src/coredump/coredump.c | 1405 |
1 files changed, 1405 insertions, 0 deletions
diff --git a/src/coredump/coredump.c b/src/coredump/coredump.c new file mode 100644 index 0000000..ecbb4bf --- /dev/null +++ b/src/coredump/coredump.c @@ -0,0 +1,1405 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include <errno.h> +#include <stdio.h> +#include <stdio_ext.h> +#include <sys/prctl.h> +#include <sys/xattr.h> +#include <unistd.h> + +#if HAVE_ELFUTILS +#include <dwarf.h> +#include <elfutils/libdwfl.h> +#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 "missing.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-util.h" +#include "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 this as array indexes for a couple of special fields we use for + * naming coredump files, and attaching xattrs, and for indexing argv[]. + + * Our pattern for man:systectl(1) kernel.core_pattern is such that the + * kernel passes fields until CONTEXT_RLIMIT as arguments in argv[]. After + * that it gets complicated: the kernel passes "comm" as one or more fields + * starting at index CONTEXT_COMM (in other words, full "comm" is under index + * CONTEXT_COMM when it does not contain spaces, which is the common + * case). This mapping is not reversible, so we prefer to retrieve "comm" + * from /proc. We only fall back to argv[CONTEXT_COMM...] when that fails. + * + * In the internal context[] array, fields before CONTEXT_COMM are the + * strings from argv[], so they should not be freed. The strings at indices + * CONTEXT_COMM and higher are allocated by us and should be freed at the + * end. + */ + CONTEXT_PID, + CONTEXT_UID, + CONTEXT_GID, + CONTEXT_SIGNAL, + CONTEXT_TIMESTAMP, + CONTEXT_RLIMIT, + CONTEXT_HOSTNAME, + CONTEXT_COMM, + CONTEXT_EXE, + CONTEXT_UNIT, + _CONTEXT_MAX +}; + +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); +} + +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 + _cleanup_(acl_freep) acl_t acl = NULL; + acl_entry_t entry; + acl_permset_t permset; + int r; + + assert(fd >= 0); + + 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 */ + + acl = acl_get_fd(fd); + if (!acl) + return log_error_errno(errno, "Failed to get ACL: %m"); + + if (acl_create_entry(&acl, &entry) < 0 || + acl_set_tag_type(entry, ACL_USER) < 0 || + acl_set_qualifier(entry, &uid) < 0) + return log_error_errno(errno, "Failed to patch ACL: %m"); + + if (acl_get_permset(entry, &permset) < 0 || + acl_add_perm(permset, ACL_READ) < 0) + return log_warning_errno(errno, "Failed to patch ACL: %m"); + + r = calc_acl_mask_if_needed(&acl); + if (r < 0) + return log_warning_errno(r, "Failed to patch ACL: %m"); + + if (acl_set_fd(fd, acl) < 0) + return log_error_errno(errno, "Failed to apply ACL: %m"); +#endif + + return 0; +} + +static int fix_xattr(int fd, const char *context[_CONTEXT_MAX]) { + + static const char * const xattrs[_CONTEXT_MAX] = { + [CONTEXT_PID] = "user.coredump.pid", + [CONTEXT_UID] = "user.coredump.uid", + [CONTEXT_GID] = "user.coredump.gid", + [CONTEXT_SIGNAL] = "user.coredump.signal", + [CONTEXT_TIMESTAMP] = "user.coredump.timestamp", + [CONTEXT_RLIMIT] = "user.coredump.rlimit", + [CONTEXT_HOSTNAME] = "user.coredump.hostname", + [CONTEXT_COMM] = "user.coredump.comm", + [CONTEXT_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 < _CONTEXT_MAX; i++) { + int k; + + if (isempty(context[i]) || !xattrs[i]) + continue; + + k = fsetxattr(fd, xattrs[i], context[i], strlen(context[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 char *context[_CONTEXT_MAX], + 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 char *context[_CONTEXT_MAX], 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[CONTEXT_COMM]); + if (!c) + return -ENOMEM; + + u = filename_escape(context[CONTEXT_UID]); + if (!u) + return -ENOMEM; + + r = sd_id128_get_boot(&boot); + if (r < 0) + return r; + + p = filename_escape(context[CONTEXT_PID]); + if (!p) + return -ENOMEM; + + t = filename_escape(context[CONTEXT_TIMESTAMP]); + if (!t) + return -ENOMEM; + + if (asprintf(ret, + "/var/lib/systemd/coredump/core.%s.%s." SD_ID128_FORMAT_STR ".%s.%s000000", + c, + u, + SD_ID128_FORMAT_VAL(boot), + p, + t) < 0) + return -ENOMEM; + + return 0; +} + +static int save_external_coredump( + const char *context[_CONTEXT_MAX], + 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[CONTEXT_UID], &uid); + if (r < 0) + return log_error_errno(r, "Failed to parse UID: %m"); + + r = safe_atou64(context[CONTEXT_RLIMIT], &rlimit); + if (r < 0) + return log_error_errno(r, "Failed to parse resource limit '%s': %m", context[CONTEXT_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[CONTEXT_PID], context[CONTEXT_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"); + + 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[CONTEXT_PID], context[CONTEXT_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_XZ || HAVE_LZ4 + /* 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 = strappend(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(&buffer, &size); + if (!stream) + return -ENOMEM; + + (void) __fsetlocking(stream, FSETLOCKING_BYCALLER); + + FOREACH_DIRENT(dent, proc_fd_dir, return -errno) { + _cleanup_fclose_ FILE *fdinfo = NULL; + _cleanup_free_ char *fdname = NULL; + int fd; + + 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 = fdopen(fd, "r"); + if (!fdinfo) { + safe_close(fd); + 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 = 0; + + 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, 0, false, cmdline); + if (r < 0) + return r; + + return 1; +} + +static int change_uid_gid(const char *context[]) { + uid_t uid; + gid_t gid; + int r; + + r = parse_uid(context[CONTEXT_UID], &uid); + if (r < 0) + return r; + + if (uid <= SYSTEM_UID_MAX) { + 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[CONTEXT_GID], &gid); + if (r < 0) + return r; + } + + return drop_privileges(uid, gid, 0); +} + +static bool is_journald_crash(const char *context[_CONTEXT_MAX]) { + assert(context); + + return streq_ptr(context[CONTEXT_UNIT], SPECIAL_JOURNALD_SERVICE); +} + +static bool is_pid1_crash(const char *context[_CONTEXT_MAX]) { + assert(context); + + return streq_ptr(context[CONTEXT_UNIT], SPECIAL_INIT_SCOPE) || + streq_ptr(context[CONTEXT_PID], "1"); +} + +#define SUBMIT_COREDUMP_FIELDS 4 + +static int submit_coredump( + const char *context[_CONTEXT_MAX], + struct iovec *iovec, + size_t n_iovec_allocated, + size_t n_iovec, + int input_fd) { + + _cleanup_close_ int coredump_fd = -1, coredump_node_fd = -1; + _cleanup_free_ char *core_message = NULL, *filename = NULL, *coredump_data = NULL; + uint64_t coredump_size = UINT64_MAX; + bool truncated = false, journald_crash; + int r; + + assert(context); + assert(iovec); + assert(n_iovec_allocated >= n_iovec + SUBMIT_COREDUMP_FIELDS); + assert(input_fd >= 0); + + journald_crash = is_journald_crash(context); + + /* 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) { + const char *coredump_filename; + + coredump_filename = strjoina("COREDUMP_FILENAME=", filename); + iovec[n_iovec++] = IOVEC_MAKE_STRING(coredump_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 strack trace if we can */ + if (coredump_size <= arg_process_size_max) { + _cleanup_free_ char *stacktrace = NULL; + + r = coredump_make_stack_trace(coredump_fd, context[CONTEXT_EXE], &stacktrace); + if (r >= 0) + core_message = strjoin("MESSAGE=Process ", context[CONTEXT_PID], + " (", context[CONTEXT_COMM], ") of user ", + context[CONTEXT_UID], " dumped core.", + journald_crash ? "\nCoredump diverted to " : "", + journald_crash ? filename : "", + "\n\n", stacktrace); + else if (r == -EINVAL) + log_warning("Failed to generate stack trace: %s", dwfl_errmsg(dwfl_errno())); + else + log_warning_errno(r, "Failed to generate stack trace: %m"); + } else + log_debug("Not generating stack trace: core size %"PRIu64" is greater than %"PRIu64" (the configured maximum)", + coredump_size, arg_process_size_max); + + if (!core_message) +#endif +log: + core_message = strjoin("MESSAGE=Process ", context[CONTEXT_PID], + " (", context[CONTEXT_COMM], ") of user ", + context[CONTEXT_UID], " dumped core.", + journald_crash && filename ? "\nCoredump diverted to " : NULL, + journald_crash && filename ? filename : NULL); + if (!core_message) + return log_oom(); + + if (journald_crash) { + /* We cannot log to the journal, so just print the message. + * The target was set previously to something safe. */ + assert(startswith(core_message, "MESSAGE=")); + log_dispatch(LOG_ERR, 0, core_message + strlen("MESSAGE=")); + return 0; + } + + iovec[n_iovec++] = IOVEC_MAKE_STRING(core_message); + + if (truncated) + iovec[n_iovec++] = IOVEC_MAKE_STRING("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) + iovec[n_iovec++] = IOVEC_MAKE(coredump_data, sz); + 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); + } + + assert(n_iovec <= n_iovec_allocated); + + r = sd_journal_sendv(iovec, n_iovec); + if (r < 0) + return log_error_errno(r, "Failed to log coredump: %m"); + + return 0; +} + +static void map_context_fields(const struct iovec *iovec, const char* context[]) { + + static const char * const context_field_names[] = { + [CONTEXT_PID] = "COREDUMP_PID=", + [CONTEXT_UID] = "COREDUMP_UID=", + [CONTEXT_GID] = "COREDUMP_GID=", + [CONTEXT_SIGNAL] = "COREDUMP_SIGNAL=", + [CONTEXT_TIMESTAMP] = "COREDUMP_TIMESTAMP=", + [CONTEXT_RLIMIT] = "COREDUMP_RLIMIT=", + [CONTEXT_HOSTNAME] = "COREDUMP_HOSTNAME=", + [CONTEXT_COMM] = "COREDUMP_COMM=", + [CONTEXT_EXE] = "COREDUMP_EXE=", + }; + + unsigned i; + + assert(iovec); + assert(context); + + for (i = 0; i < ELEMENTSOF(context_field_names); i++) { + char *p; + + if (!context_field_names[i]) + continue; + + p = memory_startswith(iovec->iov_base, iovec->iov_len, context_field_names[i]); + if (!p) + continue; + + /* 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 below) */ + context[i] = p; + break; + } +} + +static int process_socket(int fd) { + _cleanup_close_ int coredump_fd = -1; + struct iovec *iovec = NULL; + size_t n_iovec = 0, n_allocated = 0, i, k; + const char *context[_CONTEXT_MAX] = {}; + int r; + + assert(fd >= 0); + + log_setup_service(); + + log_debug("Processing coredump received on stdin..."); + + for (;;) { + union { + struct cmsghdr cmsghdr; + uint8_t buf[CMSG_SPACE(sizeof(int))]; + } control = {}; + struct msghdr mh = { + .msg_control = &control, + .msg_controllen = sizeof(control), + .msg_iovlen = 1, + }; + ssize_t n; + ssize_t l; + + if (!GREEDY_REALLOC(iovec, n_allocated, n_iovec + SUBMIT_COREDUMP_FIELDS)) { + r = log_oom(); + goto finish; + } + + l = next_datagram_size_fd(fd); + if (l < 0) { + r = log_error_errno(l, "Failed to determine datagram size to read: %m"); + goto finish; + } + + assert(l >= 0); + + iovec[n_iovec].iov_len = l; + iovec[n_iovec].iov_base = malloc(l + 1); + if (!iovec[n_iovec].iov_base) { + r = log_oom(); + goto finish; + } + + mh.msg_iov = iovec + n_iovec; + + n = recvmsg(fd, &mh, MSG_CMSG_CLOEXEC); + if (n < 0) { + free(iovec[n_iovec].iov_base); + r = log_error_errno(errno, "Failed to receive datagram: %m"); + goto finish; + } + + if (n == 0) { + struct cmsghdr *cmsg, *found = NULL; + /* The final zero-length datagram carries the file descriptor and tells us that we're done. */ + + free(iovec[n_iovec].iov_base); + + CMSG_FOREACH(cmsg, &mh) { + if (cmsg->cmsg_level == SOL_SOCKET && + cmsg->cmsg_type == SCM_RIGHTS && + cmsg->cmsg_len == CMSG_LEN(sizeof(int))) { + assert(!found); + found = cmsg; + } + } + + if (!found) { + log_error("Coredump file descriptor missing."); + r = -EBADMSG; + goto finish; + } + + assert(coredump_fd < 0); + coredump_fd = *(int*) CMSG_DATA(found); + break; + } + + /* Add trailing NUL byte, in case these are strings */ + ((char*) iovec[n_iovec].iov_base)[n] = 0; + iovec[n_iovec].iov_len = (size_t) n; + + cmsg_close_all(&mh); + map_context_fields(iovec + n_iovec, context); + n_iovec++; + } + + if (!GREEDY_REALLOC(iovec, n_allocated, n_iovec + SUBMIT_COREDUMP_FIELDS)) { + r = log_oom(); + goto finish; + } + + /* Make sure we got all data we really need */ + assert(context[CONTEXT_PID]); + assert(context[CONTEXT_UID]); + assert(context[CONTEXT_GID]); + assert(context[CONTEXT_SIGNAL]); + assert(context[CONTEXT_TIMESTAMP]); + assert(context[CONTEXT_RLIMIT]); + assert(context[CONTEXT_HOSTNAME]); + assert(context[CONTEXT_COMM]); + assert(coredump_fd >= 0); + + /* Small quirk: 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. Since we + * are reconstructing the original kernel context, we chop this off again, here. */ + k = strlen(context[CONTEXT_TIMESTAMP]); + if (k > 6) + context[CONTEXT_TIMESTAMP] = strndupa(context[CONTEXT_TIMESTAMP], k - 6); + + r = submit_coredump(context, iovec, n_allocated, n_iovec, coredump_fd); + +finish: + for (i = 0; i < n_iovec; i++) + free(iovec[i].iov_base); + free(iovec); + + return r; +} + +static int send_iovec(const struct iovec iovec[], size_t n_iovec, 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(iovec || n_iovec <= 0); + 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 < n_iovec; i++) { + struct msghdr mh = { + .msg_iov = (struct iovec*) 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] = iovec[i]; + copy[1] = (struct iovec) { + .iov_base = (char[]) { '.', '.', '.' }, + .iov_len = 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 char* set_iovec_field_free(struct iovec *iovec, size_t *n_iovec, const char *field, char *value) { + char *x; + + x = set_iovec_string_field(iovec, n_iovec, field, value); + free(value); + return x; +} + +static int gather_pid_metadata( + char* context[_CONTEXT_MAX], + char **comm_fallback, + struct iovec *iovec, size_t *n_iovec) { + + /* We need 27 empty slots in iovec! + * + * 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 n_iovec fields initialized.) */ + + uid_t owner_uid; + pid_t pid; + char *t; + const char *p; + int r, signo; + + r = parse_pid(context[CONTEXT_PID], &pid); + if (r < 0) + return log_error_errno(r, "Failed to parse PID \"%s\": %m", context[CONTEXT_PID]); + + r = get_process_comm(pid, &context[CONTEXT_COMM]); + if (r < 0) { + log_warning_errno(r, "Failed to get COMM, falling back to the command line: %m"); + context[CONTEXT_COMM] = strv_join(comm_fallback, " "); + if (!context[CONTEXT_COMM]) + return log_oom(); + } + + r = get_process_exe(pid, &context[CONTEXT_EXE]); + if (r < 0) + log_warning_errno(r, "Failed to get EXE, ignoring: %m"); + + if (cg_pid_get_unit(pid, &context[CONTEXT_UNIT]) >= 0) { + if (!is_journald_crash((const char**) context)) { + /* 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. */ + if (is_pid1_crash((const char**) context)) { + log_notice("Due to PID 1 having crashed coredump collection will now be turned off."); + disable_coredumps(); + } + + set_iovec_string_field(iovec, n_iovec, "COREDUMP_UNIT=", context[CONTEXT_UNIT]); + } + + if (cg_pid_get_user_unit(pid, &t) >= 0) + set_iovec_field_free(iovec, n_iovec, "COREDUMP_USER_UNIT=", t); + + /* The next few are mandatory */ + if (!set_iovec_string_field(iovec, n_iovec, "COREDUMP_PID=", context[CONTEXT_PID])) + return log_oom(); + + if (!set_iovec_string_field(iovec, n_iovec, "COREDUMP_UID=", context[CONTEXT_UID])) + return log_oom(); + + if (!set_iovec_string_field(iovec, n_iovec, "COREDUMP_GID=", context[CONTEXT_GID])) + return log_oom(); + + if (!set_iovec_string_field(iovec, n_iovec, "COREDUMP_SIGNAL=", context[CONTEXT_SIGNAL])) + return log_oom(); + + if (!set_iovec_string_field(iovec, n_iovec, "COREDUMP_RLIMIT=", context[CONTEXT_RLIMIT])) + return log_oom(); + + if (!set_iovec_string_field(iovec, n_iovec, "COREDUMP_HOSTNAME=", context[CONTEXT_HOSTNAME])) + return log_oom(); + + if (!set_iovec_string_field(iovec, n_iovec, "COREDUMP_COMM=", context[CONTEXT_COMM])) + return log_oom(); + + if (context[CONTEXT_EXE] && + !set_iovec_string_field(iovec, n_iovec, "COREDUMP_EXE=", context[CONTEXT_EXE])) + return log_oom(); + + if (sd_pid_get_session(pid, &t) >= 0) + set_iovec_field_free(iovec, n_iovec, "COREDUMP_SESSION=", t); + + if (sd_pid_get_owner_uid(pid, &owner_uid) >= 0) { + r = asprintf(&t, "COREDUMP_OWNER_UID=" UID_FMT, owner_uid); + if (r > 0) + iovec[(*n_iovec)++] = IOVEC_MAKE_STRING(t); + } + + if (sd_pid_get_slice(pid, &t) >= 0) + set_iovec_field_free(iovec, n_iovec, "COREDUMP_SLICE=", t); + + if (get_process_cmdline(pid, 0, false, &t) >= 0) + set_iovec_field_free(iovec, n_iovec, "COREDUMP_CMDLINE=", t); + + if (cg_pid_get_path_shifted(pid, NULL, &t) >= 0) + set_iovec_field_free(iovec, n_iovec, "COREDUMP_CGROUP=", t); + + if (compose_open_fds(pid, &t) >= 0) + set_iovec_field_free(iovec, n_iovec, "COREDUMP_OPEN_FDS=", t); + + p = procfs_file_alloca(pid, "status"); + if (read_full_file(p, &t, NULL) >= 0) + set_iovec_field_free(iovec, n_iovec, "COREDUMP_PROC_STATUS=", t); + + p = procfs_file_alloca(pid, "maps"); + if (read_full_file(p, &t, NULL) >= 0) + set_iovec_field_free(iovec, n_iovec, "COREDUMP_PROC_MAPS=", t); + + p = procfs_file_alloca(pid, "limits"); + if (read_full_file(p, &t, NULL) >= 0) + set_iovec_field_free(iovec, n_iovec, "COREDUMP_PROC_LIMITS=", t); + + p = procfs_file_alloca(pid, "cgroup"); + if (read_full_file(p, &t, NULL) >=0) + set_iovec_field_free(iovec, n_iovec, "COREDUMP_PROC_CGROUP=", t); + + p = procfs_file_alloca(pid, "mountinfo"); + if (read_full_file(p, &t, NULL) >=0) + set_iovec_field_free(iovec, n_iovec, "COREDUMP_PROC_MOUNTINFO=", t); + + if (get_process_cwd(pid, &t) >= 0) + set_iovec_field_free(iovec, n_iovec, "COREDUMP_CWD=", t); + + if (get_process_root(pid, &t) >= 0) { + bool proc_self_root_is_slash; + + proc_self_root_is_slash = strcmp(t, "/") == 0; + + set_iovec_field_free(iovec, n_iovec, "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) + set_iovec_field_free(iovec, n_iovec, "COREDUMP_CONTAINER_CMDLINE=", t); + } + + if (get_process_environ(pid, &t) >= 0) + set_iovec_field_free(iovec, n_iovec, "COREDUMP_ENVIRON=", t); + + t = strjoin("COREDUMP_TIMESTAMP=", context[CONTEXT_TIMESTAMP], "000000"); + if (t) + iovec[(*n_iovec)++] = IOVEC_MAKE_STRING(t); + + if (safe_atoi(context[CONTEXT_SIGNAL], &signo) >= 0 && SIGNAL_VALID(signo)) + set_iovec_string_field(iovec, n_iovec, "COREDUMP_SIGNAL_NAME=SIG", signal_to_string(signo)); + + return 0; /* we successfully acquired all metadata */ +} + +static int process_kernel(int argc, char* argv[]) { + + char* context[_CONTEXT_MAX] = {}; + struct iovec iovec[29 + SUBMIT_COREDUMP_FIELDS]; + size_t i, n_iovec, n_to_free = 0; + int r; + + log_debug("Processing coredump received from the kernel..."); + + if (argc < CONTEXT_COMM + 1) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Not enough arguments passed by the kernel (%i, expected %i).", + argc - 1, CONTEXT_COMM + 1 - 1); + + context[CONTEXT_PID] = argv[1 + CONTEXT_PID]; + context[CONTEXT_UID] = argv[1 + CONTEXT_UID]; + context[CONTEXT_GID] = argv[1 + CONTEXT_GID]; + context[CONTEXT_SIGNAL] = argv[1 + CONTEXT_SIGNAL]; + context[CONTEXT_TIMESTAMP] = argv[1 + CONTEXT_TIMESTAMP]; + context[CONTEXT_RLIMIT] = argv[1 + CONTEXT_RLIMIT]; + context[CONTEXT_HOSTNAME] = argv[1 + CONTEXT_HOSTNAME]; + + r = gather_pid_metadata(context, argv + 1 + CONTEXT_COMM, iovec, &n_to_free); + if (r < 0) + goto finish; + + n_iovec = n_to_free; + + iovec[n_iovec++] = IOVEC_MAKE_STRING("MESSAGE_ID=" SD_MESSAGE_COREDUMP_STR); + + assert_cc(2 == LOG_CRIT); + iovec[n_iovec++] = IOVEC_MAKE_STRING("PRIORITY=2"); + + assert(n_iovec <= ELEMENTSOF(iovec)); + + if (is_journald_crash((const char**) context) || is_pid1_crash((const char**) context)) + r = submit_coredump((const char**) context, + iovec, ELEMENTSOF(iovec), n_iovec, + STDIN_FILENO); + else + r = send_iovec(iovec, n_iovec, STDIN_FILENO); + + finish: + for (i = 0; i < n_to_free; i++) + free(iovec[i].iov_base); + + /* Those fields are allocated by gather_pid_metadata */ + free(context[CONTEXT_COMM]); + free(context[CONTEXT_EXE]); + free(context[CONTEXT_UNIT]); + + return r; +} + +static int process_backtrace(int argc, char *argv[]) { + char *context[_CONTEXT_MAX] = {}; + _cleanup_free_ char *message = NULL; + _cleanup_free_ struct iovec *iovec = NULL; + size_t n_iovec, n_allocated, n_to_free = 0, i; + int r; + JournalImporter importer = { + .fd = STDIN_FILENO, + }; + + log_debug("Processing backtrace on stdin..."); + + if (argc < CONTEXT_COMM + 1) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Not enough arguments passed (%i, expected %i).", + argc - 1, CONTEXT_COMM + 1 - 1); + + context[CONTEXT_PID] = argv[2 + CONTEXT_PID]; + context[CONTEXT_UID] = argv[2 + CONTEXT_UID]; + context[CONTEXT_GID] = argv[2 + CONTEXT_GID]; + context[CONTEXT_SIGNAL] = argv[2 + CONTEXT_SIGNAL]; + context[CONTEXT_TIMESTAMP] = argv[2 + CONTEXT_TIMESTAMP]; + context[CONTEXT_RLIMIT] = argv[2 + CONTEXT_RLIMIT]; + context[CONTEXT_HOSTNAME] = argv[2 + CONTEXT_HOSTNAME]; + + n_allocated = 34 + COREDUMP_STORAGE_EXTERNAL; + /* 26 metadata, 2 static, +unknown input, 4 storage, rounded up */ + iovec = new(struct iovec, n_allocated); + if (!iovec) + return log_oom(); + + r = gather_pid_metadata(context, argv + 2 + CONTEXT_COMM, iovec, &n_to_free); + if (r < 0) + goto finish; + if (r > 0) { + /* This was a special crash, and has already been processed. */ + r = 0; + goto finish; + } + n_iovec = n_to_free; + + 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 (!GREEDY_REALLOC(iovec, n_allocated, n_iovec + importer.iovw.count + 2)) + return log_oom(); + + if (journal_importer_eof(&importer)) { + log_warning("Did not receive a full journal entry on stdin, ignoring message sent by reporter"); + + message = strjoin("MESSAGE=Process ", context[CONTEXT_PID], + " (", context[CONTEXT_COMM], ")" + " of user ", context[CONTEXT_UID], + " failed with ", context[CONTEXT_SIGNAL]); + if (!message) { + r = log_oom(); + goto finish; + } + iovec[n_iovec++] = IOVEC_MAKE_STRING(message); + } else { + for (i = 0; i < importer.iovw.count; i++) + iovec[n_iovec++] = importer.iovw.iovec[i]; + } + + iovec[n_iovec++] = IOVEC_MAKE_STRING("MESSAGE_ID=" SD_MESSAGE_BACKTRACE_STR); + assert_cc(2 == LOG_CRIT); + iovec[n_iovec++] = IOVEC_MAKE_STRING("PRIORITY=2"); + + assert(n_iovec <= n_allocated); + + r = sd_journal_sendv(iovec, n_iovec); + if (r < 0) + log_error_errno(r, "Failed to log backtrace: %m"); + + finish: + for (i = 0; i < n_to_free; i++) + free(iovec[i].iov_base); + + /* Those fields are allocated by gather_pid_metadata */ + free(context[CONTEXT_COMM]); + free(context[CONTEXT_EXE]); + free(context[CONTEXT_UNIT]); + + 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); |