Fix double free error with -M.

2 files changed, 17 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 394b0ed4..efe4abea 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2020-07-03         Arnold D. Robbins     <arnold@skeeve.com>
+
+	Fix a double free error with -M.  Thanks to
+	"NIDE, Naoyuki" <nide@ics.nara-wu.ac.jp> for the report.
+
+	* field.c (clear_mpfr):  New macro, clears MPFR and NUMCUR bits.
+	(reset_record): Use it on the newly copied field values.
+	(purge_record): Add introductory comment since we're in the file.
+
 2020-07-01         Arnold D. Robbins     <arnold@skeeve.com>
 
 	* eval.c (posix_compare): Rewrite contributed by
diff --git a/field.c b/field.c
index 0e84447a..c21046b9 100644
--- a/field.c
+++ b/field.c
@@ -90,6 +90,8 @@ Regexp *FPAT_re_no_case = NULL;
 Regexp *FPAT_regexp = NULL;
 NODE *Null_field = NULL;
 
+#define clear_mpfr(n) ((n)->flags &= ~(MPFN | MPZN | NUMCUR))
+
 /* init_fields --- set up the fields array to start with */
 
 void
@@ -230,6 +232,7 @@ rebuild_record()
 			}
 
 			n->stptr = cops;
+			clear_mpfr(n);
 			unref(r);
 			fields_arr[i] = n;
 			assert((n->flags & WSTRCUR) == 0);
@@ -347,6 +350,11 @@ reset_record()
 	}
 }
 
+/*
+ * purge_record --- throw away the fields, make sure that
+ * 	individual nodes remain valid.
+ */
+
 static void
 purge_record()
 {