Imported Upstream version 4.13upstream/4.13

1 files changed, 26 insertions, 2 deletions

diff --git a/lib/decoding.c b/lib/decoding.c
index 2240b09..05dc236 100644
--- a/lib/decoding.c
+++ b/lib/decoding.c
@@ -43,8 +43,22 @@
 
 #define HAVE_TWO(x) (x>=2?1:0)
 
+/* Decoding flags (dflags) used in several decoding functions.
+ *  DECODE_FLAG_HAVE_TAG: The provided buffer includes a tag
+ *  DECODE_FLAG_INDEFINITE: The provided buffer is of indefinite encoding (useful
+ *                          when no tags are present).
+ *  DECODE_FLAG_LEVEL1: Internal flag to indicate a level of recursion for BER strings.
+ *  DECODE_FLAG_LEVEL2: Internal flag to indicate two levels of recursion for BER strings.
+ *  DECODE_FLAG_LEVEL3: Internal flag to indicate three levels of recursion for BER strings.
+ *                      This is the maximum levels of recursion possible to prevent stack
+ *                      exhaustion.
+ */
+
 #define DECODE_FLAG_HAVE_TAG 1
 #define DECODE_FLAG_INDEFINITE (1<<1)
+#define DECODE_FLAG_LEVEL1 (1<<2)
+#define DECODE_FLAG_LEVEL2 (1<<3)
+#define DECODE_FLAG_LEVEL3 (1<<4)
 
 #define DECR_LEN(l, s) do { \
 	  l -= s; \
@@ -2216,7 +2230,8 @@ _asn1_decode_simple_ber (unsigned int etype, const unsigned char *der,
     }
 
   /* indefinite constructed */
-  if (((dflags & DECODE_FLAG_INDEFINITE) || class == ASN1_CLASS_STRUCTURED) && ETYPE_IS_STRING(etype))
+  if ((((dflags & DECODE_FLAG_INDEFINITE) || class == ASN1_CLASS_STRUCTURED) && ETYPE_IS_STRING(etype)) &&
+      !(dflags & DECODE_FLAG_LEVEL3))
     {
       len_len = 1;
 
@@ -2236,8 +2251,17 @@ _asn1_decode_simple_ber (unsigned int etype, const unsigned char *der,
       do
         {
           unsigned tmp_len;
+          unsigned flags = DECODE_FLAG_HAVE_TAG;
+
+          if (dflags & DECODE_FLAG_LEVEL1)
+                flags |= DECODE_FLAG_LEVEL2;
+          else if (dflags & DECODE_FLAG_LEVEL2)
+		flags |= DECODE_FLAG_LEVEL3;
+	  else
+		flags |= DECODE_FLAG_LEVEL1;
 
-          result = asn1_decode_simple_ber(etype, p, der_len, &out, &out_len, &tmp_len);
+          result = _asn1_decode_simple_ber(etype, p, der_len, &out, &out_len, &tmp_len,
+                                           flags);
           if (result != ASN1_SUCCESS)
             {
               warn();