Have BER_Deocder::decode_list actually start the SEQUENCE. All callers

did it and it would be silly for it not to. Update the two existing
callers, who were both doing start_cons().decode_list().end_cons() to
just call decode_list().

Add BER_Decoder::get_next so we can get arbitrarily weird types
without having to break message chains.

Add dummy tag arguments to the ASN1_Object decoder so it can be used
from decode_optional.

3 files changed, 22 insertions, 12 deletions

diff --git a/src/asn1/ber_dec.cpp b/src/asn1/ber_dec.cpp
index dbd59988b..51b952e71 100644
--- a/src/asn1/ber_dec.cpp
+++ b/src/asn1/ber_dec.cpp
@@ -232,6 +232,12 @@ BER_Object BER_Decoder::get_next_object()
    return next;
    }
 
+BER_Decoder& BER_Decoder::get_next(BER_Object& ber)
+   {
+   ber = get_next_object();
+   return (*this);
+   }
+
 /*
 * Push a object back into the stream
 */
@@ -341,7 +347,8 @@ BER_Decoder::~BER_Decoder()
 /*
 * Request for an object to decode itself
 */
-BER_Decoder& BER_Decoder::decode(ASN1_Object& obj)
+BER_Decoder& BER_Decoder::decode(ASN1_Object& obj,
+                                 ASN1_Tag, ASN1_Tag)
    {
    obj.decode_from(*this);
    return (*this);
diff --git a/src/asn1/ber_dec.h b/src/asn1/ber_dec.h
index 6b010fcc4..6ca9aa777 100644
--- a/src/asn1/ber_dec.h
+++ b/src/asn1/ber_dec.h
@@ -29,6 +29,8 @@ class BOTAN_DLL BER_Decoder
       BER_Decoder  start_cons(ASN1_Tag type_tag, ASN1_Tag class_tag = UNIVERSAL);
       BER_Decoder& end_cons();
 
+      BER_Decoder& get_next(BER_Object& ber);
+
       BER_Decoder& raw_bytes(secure_vector<byte>& v);
       BER_Decoder& raw_bytes(std::vector<byte>& v);
 
@@ -61,7 +63,9 @@ class BOTAN_DLL BER_Decoder
                           ASN1_Tag type_tag,
                           ASN1_Tag class_tag = CONTEXT_SPECIFIC);
 
-      BER_Decoder& decode(class ASN1_Object& obj);
+      BER_Decoder& decode(class ASN1_Object& obj,
+                          ASN1_Tag type_tag = NO_OBJECT,
+                          ASN1_Tag class_tag = NO_OBJECT);
 
       BER_Decoder& decode_octet_string_bigint(class BigInt& b);
 
@@ -172,12 +176,17 @@ BER_Decoder& BER_Decoder::decode_list(std::vector<T>& vec, bool clear_it)
    if(clear_it)
       vec.clear();
 
-   while(more_items())
+   BER_Decoder list = start_cons(SEQUENCE);
+
+   while(list.more_items())
       {
       T value;
-      decode(value);
+      list.decode(value);
       vec.push_back(value);
       }
+
+   list.end_cons();
+
    return (*this);
    }
 
diff --git a/src/cert/x509/x509_ext.cpp b/src/cert/x509/x509_ext.cpp
index 751d20266..7daa58f20 100644
--- a/src/cert/x509/x509_ext.cpp
+++ b/src/cert/x509/x509_ext.cpp
@@ -418,10 +418,7 @@ std::vector<byte> Extended_Key_Usage::encode_inner() const
 */
 void Extended_Key_Usage::decode_inner(const std::vector<byte>& in)
    {
-   BER_Decoder(in)
-      .start_cons(SEQUENCE)
-         .decode_list(oids)
-      .end_cons();
+   BER_Decoder(in).decode_list(oids);
    }
 
 /*
@@ -488,10 +485,7 @@ void Certificate_Policies::decode_inner(const std::vector<byte>& in)
    {
    std::vector<Policy_Information> policies;
 
-   BER_Decoder(in)
-      .start_cons(SEQUENCE)
-         .decode_list(policies)
-      .end_cons();
+   BER_Decoder(in).decode_list(policies);
 
    oids.clear();
    for(size_t i = 0; i != policies.size(); ++i)