cryptopp: add upstream security fix for CVE-2016-9939

Fixes security issue (DoS) in Crypto++ ASN1 decoder:

https://github.com/weidai11/cryptopp/issues/346

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/cryptopp/0001-Fix-possible-DoS-in-ASN.1-decoders-CVE-2016-9939.patch

@@ -0,0 +1,69 @@
+From 3d9181d7bdd8e491f745dbc9e34bd20b6f6da069 Mon Sep 17 00:00:00 2001
+From: Gergely Nagy <ngg@tresorit.com>
+Date: Wed, 14 Dec 2016 13:19:01 +0100
+Subject: [PATCH] Fix possible DoS in ASN.1 decoders (CVE-2016-9939)
+
+Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
+---
+ asn.cpp | 10 ++++++++++
+ asn.h   |  2 ++
+ 2 files changed, 12 insertions(+)
+
+diff --git a/asn.cpp b/asn.cpp
+index 297ff01..2e923ef 100644
+--- a/asn.cpp
++++ b/asn.cpp
+@@ -123,6 +123,8 @@ size_t BERDecodeOctetString(BufferedTransformation &bt, SecByteBlock &str)
+ 	size_t bc;
+ 	if (!BERLengthDecode(bt, bc))
+ 		BERDecodeError();
++	if (bc > bt.MaxRetrievable())
++		BERDecodeError();
+ 
+ 	str.New(bc);
+ 	if (bc != bt.Get(str, bc))
+@@ -139,6 +141,8 @@ size_t BERDecodeOctetString(BufferedTransformation &bt, BufferedTransformation &
+ 	size_t bc;
+ 	if (!BERLengthDecode(bt, bc))
+ 		BERDecodeError();
++	if (bc > bt.MaxRetrievable())
++		BERDecodeError();
+ 
+ 	bt.TransferTo(str, bc);
+ 	return bc;
+@@ -161,6 +165,8 @@ size_t BERDecodeTextString(BufferedTransformation &bt, std::string &str, byte as
+ 	size_t bc;
+ 	if (!BERLengthDecode(bt, bc))
+ 		BERDecodeError();
++	if (bc > bt.MaxRetrievable())
++		BERDecodeError();
+ 
+ 	SecByteBlock temp(bc);
+ 	if (bc != bt.Get(temp, bc))
+@@ -188,6 +194,10 @@ size_t BERDecodeBitString(BufferedTransformation &bt, SecByteBlock &str, unsigne
+ 	size_t bc;
+ 	if (!BERLengthDecode(bt, bc))
+ 		BERDecodeError();
++	if (bc == 0)
++		BERDecodeError();
++	if (bc > bt.MaxRetrievable())
++		BERDecodeError();
+ 
+ 	byte unused;
+ 	if (!bt.Get(unused))
+diff --git a/asn.h b/asn.h
+index ed9de52..33f0dd0 100644
+--- a/asn.h
++++ b/asn.h
+@@ -498,6 +498,8 @@ void BERDecodeUnsigned(BufferedTransformation &in, T &w, byte asnTag = INTEGER,
+ 	bool definite = BERLengthDecode(in, bc);
+ 	if (!definite)
+ 		BERDecodeError();
++	if (bc > in.MaxRetrievable())
++		BERDecodeError();
+ 
+ 	SecByteBlock buf(bc);
+ 
+-- 
+2.10.2
+