Fix for Coverity perl5 CID 29068: Insecure temporary file (SECURE_TEMP) secure_temp: Calling mkstemp() without securely setting umask first.

The umask used for mkstemp should be secure, but umask 0600 has been
the required umask only since POSIX.1-2008.  In glibc 2.06 and earlier
the default was 0666, which is not secure.  And no explicit knowledge
of how well non-glibc platforms implement mkstemp.  Better err on the
side security, so set the umask temporarily to 0600, and then restore it.

1 files changed, 2 insertions, 0 deletions

diff --git a/perl.c b/perl.c
index 86fb8d9c4b..51deabde79 100644
--- a/perl.c
+++ b/perl.c
@@ -3762,7 +3762,9 @@ S_open_script(pTHX_ const char *scriptname, bool dosearch, bool *suidscript)
 	const char * const err = "Failed to create a fake bit bucket";
 	if (strEQ(scriptname, BIT_BUCKET)) {
 #ifdef HAS_MKSTEMP /* Hopefully mkstemp() is safe here. */
+            int old_umask = umask(0600);
 	    int tmpfd = mkstemp(tmpname);
+            umask(old_umask);
 	    if (tmpfd > -1) {
 		scriptname = tmpname;
 		close(tmpfd);