From 59071a77774c530f0ab570dda27e23a021d23972 Mon Sep 17 00:00:00 2001

From: Mark Reynolds <mreynolds@redhat.com>

Date: Thu, 23 Aug 2018 10:09:58 -0400

Subject: [PATCH] Bug 1614820 - Crash in vslapd_log_emergency_error

Description: We were not locking the error log fd before closing and reopening

             the log file.  This could cause a crash when multiple threads are

             trying to log tothe errors log.

---

 ldap/servers/slapd/log.c | 22 ++++++++++++++++------

 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/ldap/servers/slapd/log.c b/ldap/servers/slapd/log.c

index 2e4ee03a8..7dd71541b 100644

--- a/ldap/servers/slapd/log.c

+++ b/ldap/servers/slapd/log.c

@@ -2231,11 +2231,11 @@ vslapd_log_emergency_error(LOGFD fp, const char *msg, int locked)

     if (logging_hr_timestamps_enabled == 1) {

         struct timespec tsnow;

         if (clock_gettime(CLOCK_REALTIME, &tsnow) != 0) {

-            syslog(LOG_EMERG, "vslapd_log_emergency_error, Unable to determine system time for message :: %s", msg);

+            syslog(LOG_EMERG, "vslapd_log_emergency_error, Unable to determine system time for message :: %s\n", msg);

             return;

         }

         if (format_localTime_hr_log(tsnow.tv_sec, tsnow.tv_nsec, sizeof(tbuf), tbuf, &size) != 0) {

-            syslog(LOG_EMERG, "vslapd_log_emergency_error, Unable to format system time for message :: %s", msg);

+            syslog(LOG_EMERG, "vslapd_log_emergency_error, Unable to format system time for message :: %s\n", msg);

             return;

         }

     } else {

@@ -2243,14 +2243,14 @@ vslapd_log_emergency_error(LOGFD fp, const char *msg, int locked)

         time_t tnl;

         tnl = slapi_current_utc_time();

         if (format_localTime_log(tnl, sizeof(tbuf), tbuf, &size) != 0) {

-            syslog(LOG_EMERG, "vslapd_log_emergency_error, Unable to format system time for message :: %s", msg);

+            syslog(LOG_EMERG, "vslapd_log_emergency_error, Unable to format system time for message :: %s\n", msg);

             return;

         }

 #ifdef HAVE_CLOCK_GETTIME

     }

 #endif

-    PR_snprintf(buffer, sizeof(buffer), "%s - EMERG - %s", tbuf, msg);

+    PR_snprintf(buffer, sizeof(buffer), "%s - EMERG - %s\n", tbuf, msg);

     size = strlen(buffer);

     if (!locked) {

@@ -2531,7 +2531,7 @@ vslapd_log_access(char *fmt, va_list ap)

     if (SLAPI_LOG_BUFSIZ - blen < vlen) {

         /* We won't be able to fit the message in! Uh-oh! */

-        /* Should we actually just do the snprintf, and warn that message was trunced? */

+        /* Should we actually just do the snprintf, and warn that message was truncated? */

         log__error_emergency("Insufficent buffer capacity to fit timestamp and message!", 1, 0);

         return -1;

     }

@@ -4486,6 +4486,13 @@ log__error_emergency(const char *errstr, int reopen, int locked)

     if (!reopen) {

         return;

     }

+    if (!locked) {

+        /*

+         * Take the lock because we are closing and reopening the error log (fd),

+         * and we don't want any other threads trying to use this fd

+         */

+        LOG_ERROR_LOCK_WRITE();

+    }

     if (NULL != loginfo.log_error_fdes) {

         LOG_CLOSE(loginfo.log_error_fdes);

     }

@@ -4494,7 +4501,10 @@ log__error_emergency(const char *errstr, int reopen, int locked)

         PRErrorCode prerr = PR_GetError();

         syslog(LOG_ERR, "Failed to reopen errors log file, " SLAPI_COMPONENT_NAME_NSPR " error %d (%s)\n", prerr, slapd_pr_strerror(prerr));

     } else {

-        vslapd_log_emergency_error(loginfo.log_error_fdes, errstr, locked);

+        vslapd_log_emergency_error(loginfo.log_error_fdes, errstr, 1 /* locked */);

+    }

+    if (!locked) {

+        LOG_ERROR_UNLOCK_WRITE();

     }

     return;

 }

-- 

2.17.1