#include <errno.h>
#include <unistd.h>
+#include <stdio.h>
+#include <sys/prctl.h>
#include <systemd/sd-journal.h>
#include <systemd/sd-login.h>
#include "log.h"
#include "util.h"
+#include "special.h"
-#define COREDUMP_MAX (64*1024)
+#define COREDUMP_MAX (24*1024*1024)
enum {
ARG_PID = 1,
_ARG_MAX
};
+static int divert_coredump(void) {
+ FILE *f;
+ int r;
+
+ log_info("Detected coredump of the journal daemon itself, diverting coredump to /var/lib/systemd/coredump/.");
+
+ mkdir_p("/var/lib/systemd/coredump", 0755);
+
+ f = fopen("/var/lib/systemd/coredump/core.systemd-journald", "we");
+ if (!f) {
+ 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 = 0;
+ break;
+ }
+
+ q = fwrite(buffer, 1, l, f);
+ if (q != l) {
+ log_error("Failed to write coredump: %m");
+ r = -errno;
+ goto finish;
+ }
+ }
+
+ fflush(f);
+
+ if (ferror(f)) {
+ log_error("Failed to write coredump: %m");
+ r = -errno;
+ }
+
+finish:
+ fclose(f);
+ return r;
+}
+
int main(int argc, char* argv[]) {
int r, j = 0;
char *p = NULL;
ssize_t n;
pid_t pid;
+ uid_t 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;
- log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
- log_parse_environment();
- log_open();
+ prctl(PR_SET_DUMPABLE, 0);
if (argc != _ARG_MAX) {
+ log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
+ log_open();
+
log_error("Invalid number of arguments passed from kernel.");
r = -EINVAL;
goto finish;
r = parse_pid(argv[ARG_PID], &pid);
if (r < 0) {
+ log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
+ log_open();
+
log_error("Failed to parse PID.");
- r = -EINVAL;
goto finish;
}
- p = malloc(9 + COREDUMP_MAX);
- if (!p) {
- log_error("Out of memory");
- r = -ENOMEM;
- goto finish;
+ if (sd_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();
+ goto finish;
+ }
+
+ core_unit = strappend("COREDUMP_UNIT=", t);
+ free(t);
+
+ if (core_unit)
+ IOVEC_SET_STRING(iovec[j++], core_unit);
}
- memcpy(p, "COREDUMP=", 9);
+ /* OK, now we know it's not the journal, hence make use of
+ * it */
+ log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
+ log_open();
- 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;
+ r = parse_uid(argv[ARG_UID], &uid);
+ if (r < 0) {
+ log_error("Failed to parse UID.");
goto finish;
}
- zero(iovec);
- iovec[j].iov_base = p;
- iovec[j].iov_len = 9 + n;
- j++;
+ 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]);
if (core_pid)
IOVEC_SET_STRING(iovec[j++], core_session);
}
- if (sd_pid_get_unit(pid, &t) >= 0) {
- core_unit = strappend("COREDUMP_UNIT=", t);
- free(t);
-
- if (core_unit)
- IOVEC_SET_STRING(iovec[j++], core_unit);
- }
-
if (get_process_exe(pid, &t) >= 0) {
core_exe = strappend("COREDUMP_EXE=", t);
free(t);
if (core_message)
IOVEC_SET_STRING(iovec[j++], core_message);
+ /* 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;
+ }
+
+ p = malloc(9 + COREDUMP_MAX);
+ if (!p) {
+ log_error("Out of memory");
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ memcpy(p, "COREDUMP=", 9);
+
+ 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;
+ }
+
+ iovec[j].iov_base = p;
+ iovec[j].iov_len = 9 + n;
+ j++;
+
r = sd_journal_sendv(iovec, j);
if (r < 0)
log_error("Failed to send coredump: %s", strerror(-r));
~ianmdlvl / elogind.git / blobdiff