use a safer variant of realloc

This variant does not create memory leaks if allocation fails.
Report and initial patch by Pascal Cuoq.

3 files changed, 20 insertions, 4 deletions

diff --git a/lib/decoding.c b/lib/decoding.c
index 3f459f2..4fa045c 100644
--- a/lib/decoding.c
+++ b/lib/decoding.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2002-2014 Free Software Foundation, Inc.
+ * Copyright (C) 2002-2016 Free Software Foundation, Inc.
  *
  * This file is part of LIBTASN1.
  *
@@ -2193,7 +2193,7 @@ asn1_decode_simple_der (unsigned int etype, const unsigned char *der,
 
 static int append(uint8_t **dst, unsigned *dst_size, const unsigned char *src, unsigned src_size)
 {
-  *dst = realloc(*dst, *dst_size+src_size);
+  *dst = _asn1_realloc(*dst, *dst_size+src_size);
   if (*dst == NULL)
     return ASN1_MEM_ERROR;
   memcpy(*dst + *dst_size, src, src_size);
diff --git a/lib/int.h b/lib/int.h
index 322b80f..a3e890d 100644
--- a/lib/int.h
+++ b/lib/int.h
@@ -197,4 +197,20 @@ convert_old_type (unsigned int ntype)
     return ntype;
 }
 
+static inline
+void *_asn1_realloc(void *ptr, size_t size)
+{
+  void *ret;
+
+  if (size == 0)
+    return ptr;
+
+  ret = realloc(ptr, size);
+  if (ret == NULL)
+    {
+      free(ptr);
+    }
+  return ret;
+}
+
 #endif /* INT_H */
diff --git a/lib/parser_aux.c b/lib/parser_aux.c
index 8e85bf8..0a1f645 100644
--- a/lib/parser_aux.c
+++ b/lib/parser_aux.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2000-2014 Free Software Foundation, Inc.
+ * Copyright (C) 2000-2016 Free Software Foundation, Inc.
  *
  * This file is part of LIBTASN1.
  *
@@ -321,7 +321,7 @@ _asn1_append_value (asn1_node node, const void *value, unsigned int len)
       /* value is allocated */
       int prev_len = node->value_len;
       node->value_len += len;
-      node->value = realloc (node->value, node->value_len);
+      node->value = _asn1_realloc (node->value, node->value_len);
       if (node->value == NULL)
 	{
 	  node->value_len = 0;