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Rework ReadTile
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* Don't malloc for the swap line, just shuffle backwards
* Ensure that im->pixelsize is sanity checked
* Ensure that we're using the right size for the buffer from TiffReadRGBATile
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@wiredfool @radarhere
wiredfool authored and radarhere committed Jan 2, 2021
1 parent eb8c120 commit 45a62e9
Showing 1 changed file with 62 additions and 104 deletions.
166 changes: 62 additions & 104 deletions src/libImaging/TiffDecode.c
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Expand Up @@ -181,63 +181,6 @@ int ImagingLibTiffInit(ImagingCodecState state, int fp, uint32 offset) {
}


int ReadTile(TIFF* tiff, UINT32 col, UINT32 row, UINT32* buffer) {
uint16 photometric = 0;

TIFFGetField(tiff, TIFFTAG_PHOTOMETRIC, &photometric);

// To avoid dealing with YCbCr subsampling, let libtiff handle it
if (photometric == PHOTOMETRIC_YCBCR) {
UINT32 tile_width, tile_height, swap_line_size, i_row;
UINT32* swap_line;

TIFFGetField(tiff, TIFFTAG_TILEWIDTH, &tile_width);
TIFFGetField(tiff, TIFFTAG_TILELENGTH, &tile_height);

swap_line_size = tile_width * sizeof(UINT32);
if (tile_width != swap_line_size / sizeof(UINT32)) {
return -1;
}

/* Read the tile into an RGBA array */
if (!TIFFReadRGBATile(tiff, col, row, buffer)) {
return -1;
}

swap_line = (UINT32*)malloc(swap_line_size);
if (swap_line == NULL) {
return -1;
}
/*
* For some reason the TIFFReadRGBATile() function chooses the
* lower left corner as the origin. Vertically mirror scanlines.
*/
for(i_row = 0; i_row < tile_height / 2; i_row++) {
UINT32 *top_line, *bottom_line;

top_line = buffer + tile_width * i_row;
bottom_line = buffer + tile_width * (tile_height - i_row - 1);

memcpy(swap_line, top_line, 4*tile_width);
memcpy(top_line, bottom_line, 4*tile_width);
memcpy(bottom_line, swap_line, 4*tile_width);
}

free(swap_line);

return 0;
}

if (TIFFReadTile(tiff, (tdata_t)buffer, col, row, 0, 0) == -1) {
TRACE(("Decode Error, Tile at %dx%d\n", col, row));
return -1;
}

TRACE(("Successfully read tile at %dx%d; \n\n", col, row));

return 0;
}

int _decodeStripYCbCr(Imaging im, ImagingCodecState state, TIFF *tiff) {
// To avoid dealing with YCbCr subsampling, let libtiff handle it
// Use a TIFFRGBAImage wrapping the tiff image, and let libtiff handle
Expand All @@ -250,7 +193,6 @@ int _decodeStripYCbCr(Imaging im, ImagingCodecState state, TIFF *tiff) {
int ret;
TIFFRGBAImage img;
char emsg[1024] = "";
int ok;

ret = TIFFGetFieldDefaulted(tiff, TIFFTAG_ROWSPERSTRIP, &rows_per_strip);
if (ret != 1) {
Expand All @@ -261,7 +203,7 @@ int _decodeStripYCbCr(Imaging im, ImagingCodecState state, TIFF *tiff) {
if (!(TIFFRGBAImageOK(tiff, emsg) && TIFFRGBAImageBegin(&img, tiff, 0, emsg))) {
TRACE(("Decode error, msg: %s", emsg));
state->errcode = IMAGING_CODEC_BROKEN;
TIFFClose(tiff);
// nothing to clean up, just return
return -1;
}

Expand All @@ -272,17 +214,13 @@ int _decodeStripYCbCr(Imaging im, ImagingCodecState state, TIFF *tiff) {
TRACE(("Inconsistent Image Error: %d =? %d, %d =? %d",
state->xsize, img.width, state->ysize, img.height));
state->errcode = IMAGING_CODEC_BROKEN;
TIFFRGBAImageEnd(&img);
TIFFClose(tiff);
return -1;
goto decodeycbcr_err;
}

/* overflow check for row byte size */
if (INT_MAX / 4 < img.width) {
state->errcode = IMAGING_CODEC_MEMORY;
TIFFRGBAImageEnd(&img);
TIFFClose(tiff);
return -1;
goto decodeycbcr_err;
}

// TiffRGBAImages are 32bits/pixel.
Expand All @@ -291,9 +229,7 @@ int _decodeStripYCbCr(Imaging im, ImagingCodecState state, TIFF *tiff) {
/* overflow check for realloc */
if (INT_MAX / row_byte_size < rows_per_strip) {
state->errcode = IMAGING_CODEC_MEMORY;
TIFFRGBAImageEnd(&img);
TIFFClose(tiff);
return -1;
goto decodeycbcr_err;
}

state->bytes = rows_per_strip * row_byte_size;
Expand All @@ -305,9 +241,7 @@ int _decodeStripYCbCr(Imaging im, ImagingCodecState state, TIFF *tiff) {
new_data = realloc (state->buffer, state->bytes);
if (!new_data) {
state->errcode = IMAGING_CODEC_MEMORY;
TIFFRGBAImageEnd(&img);
TIFFClose(tiff);
return -1;
goto decodeycbcr_err;
}

state->buffer = new_data;
Expand All @@ -319,9 +253,7 @@ int _decodeStripYCbCr(Imaging im, ImagingCodecState state, TIFF *tiff) {
if (TIFFRGBAImageGet(&img, (UINT32 *)state->buffer, img.width, rows_to_read) == -1) {
TRACE(("Decode Error, y: %d\n", state->y ));
state->errcode = IMAGING_CODEC_BROKEN;
TIFFRGBAImageEnd(&img);
TIFFClose(tiff);
return -1;
goto decodeycbcr_err;
}

TRACE(("Decoded strip for row %d \n", state->y));
Expand All @@ -339,7 +271,12 @@ int _decodeStripYCbCr(Imaging im, ImagingCodecState state, TIFF *tiff) {
state->xsize);
}
}
TIFFRGBAImageEnd(&img);

decodeycbcr_err:
TIFFRGBAImageEnd(&img);
if (state->errcode != 0) {
return -1;
}
return 0;
}

Expand All @@ -361,7 +298,6 @@ int _decodeStrip(Imaging im, ImagingCodecState state, TIFF *tiff) {
/* overflow check for realloc */
if (INT_MAX / row_byte_size < rows_per_strip) {
state->errcode = IMAGING_CODEC_MEMORY;
TIFFClose(tiff);
return -1;
}

Expand All @@ -375,7 +311,6 @@ int _decodeStrip(Imaging im, ImagingCodecState state, TIFF *tiff) {
// call to TIFFReadEncodedStrip ...

state->errcode = IMAGING_CODEC_MEMORY;
TIFFClose(tiff);
return -1;
}

Expand All @@ -384,7 +319,6 @@ int _decodeStrip(Imaging im, ImagingCodecState state, TIFF *tiff) {
new_data = realloc (state->buffer, state->bytes);
if (!new_data) {
state->errcode = IMAGING_CODEC_MEMORY;
TIFFClose(tiff);
return -1;
}

Expand All @@ -394,7 +328,6 @@ int _decodeStrip(Imaging im, ImagingCodecState state, TIFF *tiff) {
if (TIFFReadEncodedStrip(tiff, TIFFComputeStrip(tiff, state->y, 0), (tdata_t)state->buffer, -1) == -1) {
TRACE(("Decode Error, strip %d\n", TIFFComputeStrip(tiff, state->y, 0)));
state->errcode = IMAGING_CODEC_BROKEN;
TIFFClose(tiff);
return -1;
}

Expand Down Expand Up @@ -423,7 +356,6 @@ int ImagingLibTiffDecode(Imaging im, ImagingCodecState state, UINT8* buffer, Py_
TIFF *tiff;
uint16 photometric = 0; // init to not PHOTOMETRIC_YCBCR
int isYCbCr = 0;
int ret;

/* buffer is the encoded file, bytes is the length of the encoded file */
/* it all ends up in state->buffer, which is a uint8* from Imaging.h */
Expand Down Expand Up @@ -480,7 +412,7 @@ int ImagingLibTiffDecode(Imaging im, ImagingCodecState state, UINT8* buffer, Py_
rv = TIFFSetSubDirectory(tiff, ifdoffset);
if (!rv){
TRACE(("error in TIFFSetSubDirectory"));
return -1;
goto decode_err;
}
}

Expand All @@ -490,7 +422,7 @@ int ImagingLibTiffDecode(Imaging im, ImagingCodecState state, UINT8* buffer, Py_

if (TIFFIsTiled(tiff)) {
INT32 x, y, tile_y;
UINT32 tile_width, tile_length, current_tile_width, row_byte_size;
UINT32 tile_width, tile_length, current_tile_length, current_line, current_tile_width, row_byte_size;
UINT8 *new_data;

TIFFGetField(tiff, TIFFTAG_TILEWIDTH, &tile_width);
Expand All @@ -499,36 +431,42 @@ int ImagingLibTiffDecode(Imaging im, ImagingCodecState state, UINT8* buffer, Py_
/* overflow check for row_byte_size calculation */
if ((UINT32) INT_MAX / state->bits < tile_width) {
state->errcode = IMAGING_CODEC_MEMORY;
TIFFClose(tiff);
return -1;
goto decode_err;
}

// We could use TIFFTileSize, but for YCbCr data it returns subsampled data size
row_byte_size = (tile_width * state->bits + 7) / 8;

if (isYCbCr) {
row_byte_size = tile_width * 4;
/* sanity check, we use this value in shuffle below */
if (im->pixelsize != 4) {
state->errcode = IMAGING_CODEC_BROKEN;
goto decode_err;
}
} else {
// We could use TIFFTileSize, but for YCbCr data it returns subsampled data size
row_byte_size = (tile_width * state->bits + 7) / 8;
}

/* overflow check for realloc */
if (INT_MAX / row_byte_size < tile_length) {
state->errcode = IMAGING_CODEC_MEMORY;
TIFFClose(tiff);
return -1;
goto decode_err;
}

state->bytes = row_byte_size * tile_length;

if (TIFFTileSize(tiff) > state->bytes) {
// If the strip size as expected by LibTiff isn't what we're expecting, abort.
state->errcode = IMAGING_CODEC_MEMORY;
TIFFClose(tiff);
return -1;
goto decode_err;
}

/* realloc to fit whole tile */
/* malloc check above */
new_data = realloc (state->buffer, state->bytes);
if (!new_data) {
state->errcode = IMAGING_CODEC_MEMORY;
TIFFClose(tiff);
return -1;
goto decode_err;
}

state->buffer = new_data;
Expand All @@ -537,41 +475,61 @@ int ImagingLibTiffDecode(Imaging im, ImagingCodecState state, UINT8* buffer, Py_

for (y = state->yoff; y < state->ysize; y += tile_length) {
for (x = state->xoff; x < state->xsize; x += tile_width) {
if (ReadTile(tiff, x, y, (UINT32*) state->buffer) == -1) {
TRACE(("Decode Error, Tile at %dx%d\n", x, y));
state->errcode = IMAGING_CODEC_BROKEN;
TIFFClose(tiff);
return -1;
if (isYCbCr) {
/* To avoid dealing with YCbCr subsampling, let libtiff handle it */
if (!TIFFReadRGBATile(tiff, x, y, (UINT32 *)state->buffer)) {
TRACE(("Decode Error, Tile at %dx%d\n", x, y));
state->errcode = IMAGING_CODEC_BROKEN;
goto decode_err;
}
} else {
if (TIFFReadTile(tiff, (tdata_t)state->buffer, x, y, 0, 0) == -1) {
TRACE(("Decode Error, Tile at %dx%d\n", x, y));
state->errcode = IMAGING_CODEC_BROKEN;
goto decode_err;
}
}

TRACE(("Read tile at %dx%d; \n\n", x, y));

current_tile_width = min((INT32) tile_width, state->xsize - x);

current_tile_length = min((INT32) tile_length, state->ysize - y);
// iterate over each line in the tile and stuff data into image
for (tile_y = 0; tile_y < min((INT32) tile_length, state->ysize - y); tile_y++) {
for (tile_y = 0; tile_y < current_tile_length; tile_y++) {
TRACE(("Writing tile data at %dx%d using tile_width: %d; \n", tile_y + y, x, current_tile_width));

// UINT8 * bbb = state->buffer + tile_y * row_byte_size;
// TRACE(("chars: %x%x%x%x\n", ((UINT8 *)bbb)[0], ((UINT8 *)bbb)[1], ((UINT8 *)bbb)[2], ((UINT8 *)bbb)[3]));

/*
* For some reason the TIFFReadRGBATile() function
* chooses the lower left corner as the origin.
* Vertically mirror by shuffling the scanlines
* backwards
*/

if (isYCbCr) {
current_line = tile_length - tile_y - 1;
} else {
current_line = tile_y;
}

state->shuffle((UINT8*) im->image[tile_y + y] + x * im->pixelsize,
state->buffer + tile_y * row_byte_size,
state->buffer + current_line * row_byte_size,
current_tile_width
);
}
}
}
} else {
if (!isYCbCr) {
ret = _decodeStrip(im, state, tiff);
_decodeStrip(im, state, tiff);
}
else {
ret = _decodeStripYCbCr(im, state, tiff);
_decodeStripYCbCr(im, state, tiff);
}
if (ret == -1) { return ret; }
}

decode_err:
TIFFClose(tiff);
TRACE(("Done Decoding, Returning \n"));
// Returning -1 here to force ImageFile.load to break, rather than
Expand Down

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