From 532a4f3d60f6981b22beb32e6ff688ec41f87e26 Mon Sep 17 00:00:00 2001 From: Jay Berkenbilt Date: Tue, 2 Nov 2021 17:54:10 -0400 Subject: Detect recoverable but invalid zlib data streams (fixes #562) --- libqpdf/Pl_Flate.cc | 35 ++++++++++++++++++++++++++++++++--- 1 file changed, 32 insertions(+), 3 deletions(-) (limited to 'libqpdf/Pl_Flate.cc') diff --git a/libqpdf/Pl_Flate.cc b/libqpdf/Pl_Flate.cc index 1eca837e..ee07b6f1 100644 --- a/libqpdf/Pl_Flate.cc +++ b/libqpdf/Pl_Flate.cc @@ -71,6 +71,21 @@ Pl_Flate::~Pl_Flate() { } +void +Pl_Flate::setWarnCallback(std::function callback) +{ + this->m->callback = callback; +} + +void +Pl_Flate::warn(char const* msg, int code) +{ + if (this->m->callback != nullptr) + { + this->m->callback(msg, code); + } +} + void Pl_Flate::write(unsigned char* data, size_t len) { @@ -164,7 +179,14 @@ Pl_Flate::handleData(unsigned char* data, size_t len, int flush) // Probably shouldn't be able to happen, but possible as a // boundary condition: if the last call to inflate exactly // filled the output buffer, it's possible that the next - // call to inflate could have nothing to do. + // call to inflate could have nothing to do. There are PDF + // files in the wild that have this error (including at + // least one in qpdf's test suite). In some cases, we want + // to know about this, because it indicates incorrect + // compression, so call a callback if provided. + this->warn( + "input stream is complete but output may still be valid", + err); done = true; break; @@ -231,8 +253,15 @@ Pl_Flate::finish() } catch (std::exception& e) { - this->getNext()->finish(); - throw e; + try + { + this->getNext()->finish(); + } + catch (...) + { + // ignore secondary exception + } + throw std::runtime_error(e.what()); } this->getNext()->finish(); } -- cgit v1.2.3-54-g00ecf