From 7b9f23a99a1ea3e97eaecf80ef29e2805e351b8f Mon Sep 17 00:00:00 2001 From: Jay Berkenbilt Date: Sat, 3 Mar 2018 11:35:01 -0500 Subject: Ignore zlib data check errors (fixes #191) --- libqpdf/Pl_Flate.cc | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'libqpdf/Pl_Flate.cc') diff --git a/libqpdf/Pl_Flate.cc b/libqpdf/Pl_Flate.cc index 212f7e1d..3becc135 100644 --- a/libqpdf/Pl_Flate.cc +++ b/libqpdf/Pl_Flate.cc @@ -1,5 +1,6 @@ #include #include +#include #include @@ -71,7 +72,8 @@ Pl_Flate::write(unsigned char* data, size_t len) while (bytes_left > 0) { size_t bytes = (bytes_left >= max_bytes ? max_bytes : bytes_left); - handleData(buf, bytes, Z_NO_FLUSH); + handleData(buf, bytes, + (action == a_inflate ? Z_SYNC_FLUSH : Z_NO_FLUSH)); bytes_left -= bytes; buf += bytes; } @@ -125,6 +127,14 @@ Pl_Flate::handleData(unsigned char* data, int len, int flush) { err = inflate(&zstream, flush); } + if ((action == a_inflate) && (err != Z_OK) && zstream.msg && + (strcmp(zstream.msg, "incorrect data check") == 0)) + { + // Other PDF readers ignore this specific error. Combining + // this with Z_SYNC_FLUSH enables qpdf to handle some + // broken zlib streams without losing data. + err = Z_STREAM_END; + } switch (err) { case Z_BUF_ERROR: -- cgit v1.2.3-54-g00ecf