mirror of
https://git.code.sf.net/p/libpng/code.git
synced 2025-07-10 18:04:09 +02:00
[libpng16] Unknown handling fixes and clean up. This adds more correct option
control of the unknown handling, corrects the pre-existing bug where the per-chunk 'keep' setting is ignored and makes it possible to skip IDAT chunks in the sequential reader (broken in earlier 1.6 versions). There is a new test program, test-unknown.c, which is a work in progress (not currently part of the test suite). Comments in the header files now explain how the unknown handling works.
This commit is contained in:
John Bowler
committed by
Glenn Randers-Pehrson
Glenn Randers-Pehrson
parent
b593b3f035
commit
e9567514dd
82
pngread.c
82
pngread.c
@@ -91,6 +91,10 @@ png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
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void PNGAPI
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png_read_info(png_structrp png_ptr, png_inforp info_ptr)
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{
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#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
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int keep;
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#endif
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png_debug(1, "in png_read_info");
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if (png_ptr == NULL || info_ptr == NULL)
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@@ -104,13 +108,30 @@ png_read_info(png_structrp png_ptr, png_inforp info_ptr)
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png_uint_32 length = png_read_chunk_header(png_ptr);
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png_uint_32 chunk_name = png_ptr->chunk_name;
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/* IDAT logic needs to happen here to simplify getting the two flags
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* right.
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*/
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if (chunk_name == png_IDAT)
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{
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if (!(png_ptr->mode & PNG_HAVE_IHDR))
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png_chunk_error(png_ptr, "Missing IHDR before IDAT");
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else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
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!(png_ptr->mode & PNG_HAVE_PLTE))
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png_chunk_error(png_ptr, "Missing PLTE before IDAT");
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else if (png_ptr->mode & PNG_AFTER_IDAT)
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png_chunk_benign_error(png_ptr, "Too many IDATs found");
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png_ptr->mode |= PNG_HAVE_IDAT;
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}
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else if (png_ptr->mode & PNG_HAVE_IDAT)
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png_ptr->mode |= PNG_AFTER_IDAT;
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/* This should be a binary subdivision search or a hash for
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* matching the chunk name rather than a linear search.
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*/
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if (chunk_name == png_IDAT)
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if (png_ptr->mode & PNG_AFTER_IDAT)
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png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
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if (chunk_name == png_IHDR)
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png_handle_IHDR(png_ptr, info_ptr, length);
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@@ -118,26 +139,16 @@ png_read_info(png_structrp png_ptr, png_inforp info_ptr)
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png_handle_IEND(png_ptr, info_ptr, length);
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#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
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else if (png_chunk_unknown_handling(png_ptr, chunk_name) !=
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PNG_HANDLE_CHUNK_AS_DEFAULT)
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else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)))
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{
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if (chunk_name == png_IDAT)
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png_ptr->mode |= PNG_HAVE_IDAT;
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png_handle_unknown(png_ptr, info_ptr, length);
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png_handle_unknown(png_ptr, info_ptr, length, keep);
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if (chunk_name == png_PLTE)
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png_ptr->mode |= PNG_HAVE_PLTE;
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else if (chunk_name == png_IDAT)
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{
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if (!(png_ptr->mode & PNG_HAVE_IHDR))
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png_error(png_ptr, "Missing IHDR before IDAT");
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else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
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!(png_ptr->mode & PNG_HAVE_PLTE))
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png_error(png_ptr, "Missing PLTE before IDAT");
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png_ptr->idat_size = 0; /* It has been consumed */
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break;
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}
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}
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@@ -147,15 +158,7 @@ png_read_info(png_structrp png_ptr, png_inforp info_ptr)
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else if (chunk_name == png_IDAT)
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{
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if (!(png_ptr->mode & PNG_HAVE_IHDR))
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png_error(png_ptr, "Missing IHDR before IDAT");
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else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
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!(png_ptr->mode & PNG_HAVE_PLTE))
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png_error(png_ptr, "Missing PLTE before IDAT");
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png_ptr->idat_size = length;
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png_ptr->mode |= PNG_HAVE_IDAT;
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break;
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}
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@@ -245,7 +248,8 @@ png_read_info(png_structrp png_ptr, png_inforp info_ptr)
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#endif
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else
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png_handle_unknown(png_ptr, info_ptr, length);
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png_handle_unknown(png_ptr, info_ptr, length,
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PNG_HANDLE_CHUNK_AS_DEFAULT);
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}
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}
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#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
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@@ -683,6 +687,10 @@ png_read_image(png_structrp png_ptr, png_bytepp image)
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void PNGAPI
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png_read_end(png_structrp png_ptr, png_inforp info_ptr)
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{
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#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
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int keep;
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#endif
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png_debug(1, "in png_read_end");
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if (png_ptr == NULL)
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@@ -691,7 +699,10 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
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/* If png_read_end is called in the middle of reading the rows there may
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* still be pending IDAT data and an owned zstream. Deal with this here.
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*/
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png_read_finish_IDAT(png_ptr);
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#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
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if (!png_chunk_unknown_handling(png_ptr, png_IDAT))
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#endif
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png_read_finish_IDAT(png_ptr);
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#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
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/* Report invalid palette index; added at libng-1.5.10 */
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@@ -712,15 +723,14 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
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png_handle_IEND(png_ptr, info_ptr, length);
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#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
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else if (png_chunk_unknown_handling(png_ptr, chunk_name) !=
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PNG_HANDLE_CHUNK_AS_DEFAULT)
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else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)))
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{
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if (chunk_name == png_IDAT)
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{
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if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
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png_benign_error(png_ptr, "Too many IDATs found");
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}
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png_handle_unknown(png_ptr, info_ptr, length);
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png_handle_unknown(png_ptr, info_ptr, length, keep);
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if (chunk_name == png_PLTE)
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png_ptr->mode |= PNG_HAVE_PLTE;
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}
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@@ -825,7 +835,8 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
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#endif
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else
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png_handle_unknown(png_ptr, info_ptr, length);
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png_handle_unknown(png_ptr, info_ptr, length,
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PNG_HANDLE_CHUNK_AS_DEFAULT);
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} while (!(png_ptr->mode & PNG_HAVE_IEND));
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}
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#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
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@@ -866,11 +877,12 @@ png_read_destroy(png_structrp png_ptr)
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png_free(png_ptr, png_ptr->save_buffer);
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#endif
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#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
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#if (defined PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) &&\
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(defined PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
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png_free(png_ptr, png_ptr->unknown_chunk.data);
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#endif
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#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
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#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
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png_free(png_ptr, png_ptr->chunk_list);
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#endif
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@@ -1476,11 +1488,11 @@ png_image_skip_unused_chunks(png_structrp png_ptr)
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/* Ignore unknown chunks and all other chunks except for the
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* IHDR, PLTE, tRNS, IDAT, and IEND chunks.
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*/
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png_set_keep_unknown_chunks(png_ptr, 1 /* PNG_HANDLE_CHUNK_NEVER */,
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png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_NEVER,
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NULL, -1);
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/* But do not ignore image data handling chunks */
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png_set_keep_unknown_chunks(png_ptr, 0 /* PNG_HANDLE_CHUNK_AS_DEFAULT */,
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png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_AS_DEFAULT,
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chunks_to_process, (sizeof chunks_to_process)/5);
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}
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}
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