From 3d9181d7bdd8e491f745dbc9e34bd20b6f6da069 Mon Sep 17 00:00:00 2001 From: Gergely Nagy Date: Wed, 14 Dec 2016 13:19:01 +0100 Subject: [PATCH] Fix possible DoS in ASN.1 decoders (CVE-2016-9939) --- 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 @@ -122,6 +122,8 @@ size_t BERDecodeOctetString(BufferedTran size_t bc; if (!BERLengthDecode(bt, bc)) BERDecodeError(); + if (bc > bt.MaxRetrievable()) + BERDecodeError(); str.resize(bc); if (bc != bt.Get(str, bc)) @@ -138,6 +140,8 @@ 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; @@ -160,6 +164,8 @@ 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)) @@ -187,6 +193,10 @@ 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 @@ -332,6 +332,8 @@ void BERDecodeUnsigned(BufferedTransform size_t bc; BERLengthDecode(in, bc); + if (bc > in.MaxRetrievable()) + BERDecodeError(); SecByteBlock buf(bc);