openssh/openssh-4.6p1-blocksigalrm.diff

49 lines
1.2 KiB
Diff

--- log.c
+++ log.c
@@ -50,6 +50,7 @@
#include "xmalloc.h"
#include "log.h"
+#include <signal.h>
static LogLevel log_level = SYSLOG_LEVEL_INFO;
static int log_on_stderr = 1;
@@ -313,6 +314,7 @@
char fmtbuf[MSGBUFSIZ];
char *txt = NULL;
int pri = LOG_INFO;
+ sigset_t nset, oset;
if (level > log_level)
return;
@@ -351,6 +353,7 @@
pri = LOG_ERR;
break;
}
+
if (txt != NULL) {
snprintf(fmtbuf, sizeof(fmtbuf), "%s: %s", txt, fmt);
vsnprintf(msgbuf, sizeof(msgbuf), fmtbuf, args);
@@ -363,6 +366,14 @@
snprintf(msgbuf, sizeof msgbuf, "%s\r\n", fmtbuf);
write(STDERR_FILENO, msgbuf, strlen(msgbuf));
} else {
+ /* Prevent a race between the grace_alarm
+ * which writes a log message and terminates
+ * and main sshd code that leads to deadlock
+ * as syslog is not async safe.
+ */
+ sigemptyset(&nset);
+ sigaddset(&nset, SIGALRM);
+ sigprocmask(SIG_BLOCK, &nset, &oset);
#if defined(HAVE_OPENLOG_R) && defined(SYSLOG_DATA_INIT)
openlog_r(argv0 ? argv0 : __progname, LOG_PID, log_facility, &sdata);
syslog_r(pri, &sdata, "%.500s", fmtbuf);
@@ -372,5 +383,6 @@
syslog(pri, "%.500s", fmtbuf);
closelog();
#endif
+ sigprocmask(SIG_SETMASK, &oset, NULL);
}
}