From 9cf879cebac7577b5a4986155bae134f31cb91a0 Mon Sep 17 00:00:00 2001 From: Jennifer Herbert Date: Tue, 7 Jul 2015 16:38:59 +0000 Subject: [PATCH] libxc: Prevent NULL pointer dereference in stdiostream_vmessage() Unlikely that it may seem localtime_r could fail, which would result in a null pointer dereference. In this case, it shoud log the errno, (instead of the date/time), and and continue its logging, as this is still useful. Signed-off-by: Jennifer Herbert Acked-by: Ian Jackson --- tools/libxc/xtl_logger_stdio.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/tools/libxc/xtl_logger_stdio.c b/tools/libxc/xtl_logger_stdio.c index d8646e08b9..b28ef730a3 100644 --- a/tools/libxc/xtl_logger_stdio.c +++ b/tools/libxc/xtl_logger_stdio.c @@ -61,10 +61,13 @@ static void stdiostream_vmessage(xentoollog_logger *logger_in, struct tm lt_buf; time_t now = time(0); struct tm *lt= localtime_r(&now, <_buf); - fprintf(lg->f, "%04d-%02d-%02d %02d:%02d:%02d %s ", - lt->tm_year+1900, lt->tm_mon+1, lt->tm_mday, - lt->tm_hour, lt->tm_min, lt->tm_sec, - tzname[!!lt->tm_isdst]); + if (lt != NULL) + fprintf(lg->f, "%04d-%02d-%02d %02d:%02d:%02d %s ", + lt->tm_year+1900, lt->tm_mon+1, lt->tm_mday, + lt->tm_hour, lt->tm_min, lt->tm_sec, + tzname[!!lt->tm_isdst]); + else + fprintf(lg->f, "[localtime_r failed: %d] ", errno); } if (lg->flags & XTL_STDIOSTREAM_SHOW_PID) fprintf(lg->f, "[%lu] ", (unsigned long)getpid()); -- 2.30.2