Viktor Semykin : windowscodecs: Fixed loading png from streams.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 2d5c861f750eea985a45c726f31576d941e824e4
URL:    http://source.winehq.org/git/wine.git/?a=commit;h=2d5c861f750eea985a45c726f3...

Author: Viktor Semykin 
Date:   Thu Mar 30 13:52:13 2017 -0300

windowscodecs: Fixed loading png from streams.

Png decoder was making one extra seek after it met IEND chunk. This led to
crashes of some software.

Signed-off-by: Viktor Semykin 
Signed-off-by: Vincent Povirk 
Signed-off-by: Alexandre Julliard

---

dlls/windowscodecs/pngformat.c       | 7 +++----
 dlls/windowscodecs/tests/pngformat.c | 2 +-
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/dlls/windowscodecs/pngformat.c b/dlls/windowscodecs/pngformat.c
index 990dcf6..c98a6a7 100644
--- a/dlls/windowscodecs/pngformat.c
+++ b/dlls/windowscodecs/pngformat.c
@@ -774,11 +774,12 @@ static HRESULT WINAPI PngDecoder_Initialize(IWICBitmapDecoder *iface, IStream *p

/* Find the metadata chunks in the file. */
     seek.QuadPart = 8;
-    hr = IStream_Seek(pIStream, seek, STREAM_SEEK_SET, &chunk_start);
-    if (FAILED(hr)) goto end;

do
     {
+        hr = IStream_Seek(pIStream, seek, STREAM_SEEK_SET, &chunk_start);
+        if (FAILED(hr)) goto end;
+
         hr = read_png_chunk(pIStream, chunk_type, NULL, &chunk_size);
         if (FAILED(hr)) goto end;

@@ -816,8 +817,6 @@ static HRESULT WINAPI PngDecoder_Initialize(IWICBitmapDecoder *iface, IStream *p
         }

seek.QuadPart = chunk_start.QuadPart + chunk_size + 12; /* skip data and CRC */
-        hr = IStream_Seek(pIStream, seek, STREAM_SEEK_SET, &chunk_start);
-        if (FAILED(hr)) goto end;
     } while (memcmp(chunk_type, "IEND", 4));

This->stream = pIStream;
diff --git a/dlls/windowscodecs/tests/pngformat.c b/dlls/windowscodecs/tests/pngformat.c
index e9a0c18..02e0b1c 100644
--- a/dlls/windowscodecs/tests/pngformat.c
+++ b/dlls/windowscodecs/tests/pngformat.c
@@ -306,7 +306,7 @@ static IWICBitmapDecoder *create_decoder(const void *image_data, UINT image_size

zero.QuadPart = 0;
     IStream_Seek (stream, zero, STREAM_SEEK_CUR, &pos);
-    todo_wine ok(pos.QuadPart < image_size, "seek beyond the end of stream: %x%08x >= %x\n",
+    ok(pos.QuadPart < image_size, "seek beyond the end of stream: %x%08x >= %x\n",
        (UINT)(pos.QuadPart >> 32), (UINT)pos.QuadPart, image_size);

refcount = IStream_Release(stream);