From 225cd9dac27d685833156dfc249838cda11cd2ef Mon Sep 17 00:00:00 2001 From: Jay Berkenbilt Date: Wed, 21 Aug 2019 12:50:36 -0400 Subject: Protect against coding error of re-entrant parsing --- libqpdf/QPDF.cc | 15 +++++++++++++++ libqpdf/QPDFObjectHandle.cc | 6 +++++- 2 files changed, 20 insertions(+), 1 deletion(-) (limited to 'libqpdf') diff --git a/libqpdf/QPDF.cc b/libqpdf/QPDF.cc index 068630d1..1d54ef44 100644 --- a/libqpdf/QPDF.cc +++ b/libqpdf/QPDF.cc @@ -150,6 +150,7 @@ QPDF::Members::Members() : reconstructed_xref(false), fixed_dangling_refs(false), immediate_copy_from(false), + in_parse(false), first_xref_item_offset(0), uncompressed_after_compressed(false) { @@ -416,6 +417,20 @@ QPDF::parse(char const* password) findAttachmentStreams(); } +void +QPDF::inParse(bool v) +{ + if (this->m->in_parse == v) + { + // This happens of QPDFObjectHandle::parseInternal tries to + // resolve an indirect object while it is parsing. + throw std::logic_error( + "QPDF: re-entrant parsing detected. This is a qpdf bug." + " Please report at https://github.com/qpdf/qpdf/issues."); + } + this->m->in_parse = v; +} + void QPDF::warn(QPDFExc const& e) { diff --git a/libqpdf/QPDFObjectHandle.cc b/libqpdf/QPDFObjectHandle.cc index 1b3b64b0..6240395d 100644 --- a/libqpdf/QPDFObjectHandle.cc +++ b/libqpdf/QPDFObjectHandle.cc @@ -1714,7 +1714,11 @@ QPDFObjectHandle::parseInternal(PointerHolder input, // This method must take care not to resolve any objects. Don't // check the type of any object without first ensuring that it is // a direct object. Otherwise, doing so may have the side effect - // of reading the object and changing the file pointer. + // of reading the object and changing the file pointer. If you do + // this, it will cause a logic error to be thrown from + // QPDF::inParse(). + + QPDF::ParseGuard pg(context); empty = false; -- cgit v1.2.3-54-g00ecf