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authorDan Sinclair <dsinclair@chromium.org>2017-06-13 15:21:14 -0400
committerChromium commit bot <commit-bot@chromium.org>2017-06-13 19:33:05 +0000
commit957480c17682008ae2a14723868fcdcab89b6577 (patch)
treecf5f1cb09c4385b7a107d8c8efcc99ea046849f8 /core/fpdfapi
parent6500c6faf82f636d55c9ca5682711022890bef1d (diff)
downloadpdfium-957480c17682008ae2a14723868fcdcab89b6577.tar.xz
Allow zero length streams when parsing.chromium/3130
It's possible to create a stream of length 0 in a PDF document. Currently the code will early exit and return a nullptr. This causes issues when you want to print the given PDF as the FPDF_ImportPages code ends up only generating up to the zero length object. This CL allows creating streams with length 0 and updates the PDF saving code to output a blank stream. Bug: chromium:732380 Change-Id: I44182ba4aaac7c51284b002ba01bbc34b6bcf9e0 Reviewed-on: https://pdfium-review.googlesource.com/6490 Reviewed-by: Lei Zhang <thestig@chromium.org> Commit-Queue: dsinclair <dsinclair@chromium.org>
Diffstat (limited to 'core/fpdfapi')
-rw-r--r--core/fpdfapi/edit/cpdf_creator.cpp14
-rw-r--r--core/fpdfapi/parser/cpdf_syntax_parser.cpp8
2 files changed, 15 insertions, 7 deletions
diff --git a/core/fpdfapi/edit/cpdf_creator.cpp b/core/fpdfapi/edit/cpdf_creator.cpp
index 1c0cd69a4b..858d56cbaf 100644
--- a/core/fpdfapi/edit/cpdf_creator.cpp
+++ b/core/fpdfapi/edit/cpdf_creator.cpp
@@ -171,13 +171,21 @@ bool CPDF_Creator::WriteStream(const CPDF_Object* pStream,
encoder.GetDict()->SetNewFor<CPDF_Number>(
"Length", static_cast<int>(encryptor.GetSize()));
}
+
if (!WriteDirectObj(objnum, encoder.GetDict(), true) ||
- !m_Archive->WriteString("stream\r\n") ||
- !m_Archive->WriteBlock(encryptor.GetData(), encryptor.GetSize()) ||
- !m_Archive->WriteString("\r\nendstream")) {
+ !m_Archive->WriteString("stream\r\n")) {
+ return false;
+ }
+
+ // Allow for empty streams.
+ if (encryptor.GetSize() > 0 &&
+ !m_Archive->WriteBlock(encryptor.GetData(), encryptor.GetSize())) {
return false;
}
+ if (!m_Archive->WriteString("\r\nendstream"))
+ return false;
+
return true;
}
diff --git a/core/fpdfapi/parser/cpdf_syntax_parser.cpp b/core/fpdfapi/parser/cpdf_syntax_parser.cpp
index fe1a197028..9dccbd936e 100644
--- a/core/fpdfapi/parser/cpdf_syntax_parser.cpp
+++ b/core/fpdfapi/parser/cpdf_syntax_parser.cpp
@@ -725,10 +725,11 @@ std::unique_ptr<CPDF_Stream> CPDF_SyntaxParser::ReadStream(
}
m_Pos = streamStartPos;
}
-
- // Read up to the end of the buffer.
+ // Read up to the end of the buffer. Note, we allow zero length streams as
+ // we need to pass them through when we are importing pages into a new
+ // document.
len = std::min(len, m_FileLen - m_Pos - m_HeaderOffset);
- if (len <= 0)
+ if (len < 0)
return nullptr;
std::unique_ptr<uint8_t, FxFreeDeleter> pData;
@@ -746,7 +747,6 @@ std::unique_ptr<CPDF_Stream> CPDF_SyntaxParser::ReadStream(
pData = dest_buf.DetachBuffer();
}
}
-
auto pStream =
pdfium::MakeUnique<CPDF_Stream>(std::move(pData), len, std::move(pDict));
streamStartPos = m_Pos;