forked from osmocom/wireshark
478 lines
14 KiB
C
478 lines
14 KiB
C
/* packet-image-png.c
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*
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* Routines for PNG (Portable Network Graphics) image file dissection
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*
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* $Id$
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*
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* Copyright 2006 Ronnie Sahlberg
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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/* See http://www.w3.org/TR/PNG for specification
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*/
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#define NEW_PROTO_TREE_API
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#include "config.h"
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#include <glib.h>
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#include <epan/packet.h>
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#include <epan/exceptions.h>
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static header_field_info *hfi_png = NULL;
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#define PNG_HFI_INIT HFI_INIT(proto_png)
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static header_field_info hfi_png_signature PNG_HFI_INIT = {
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"PNG Signature", "png.signature", FT_BYTES, BASE_NONE,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_chunk_data PNG_HFI_INIT = {
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"Data", "png.chunk.data", FT_NONE, BASE_NONE,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_chunk_type PNG_HFI_INIT = {
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"Chunk", "png.chunk.type", FT_STRING, BASE_NONE,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_chunk_len PNG_HFI_INIT = {
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"Len", "png.chunk.len", FT_UINT32, BASE_DEC,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_chunk_crc PNG_HFI_INIT = {
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"CRC", "png.chunk.crc", FT_UINT32, BASE_HEX,
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NULL, 0, NULL, HFILL };
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static const true_false_string png_chunk_anc = {
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"This is an ANCILLARY chunk",
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"This is a CRITICAL chunk"
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};
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static header_field_info hfi_png_chunk_flag_anc PNG_HFI_INIT = {
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"Ancillary", "png.chunk.flag.ancillary", FT_BOOLEAN, 32,
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TFS(&png_chunk_anc), 0x20000000, NULL, HFILL };
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static const true_false_string png_chunk_priv = {
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"This is a PRIVATE chunk",
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"This is a PUBLIC chunk"
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};
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static header_field_info hfi_png_chunk_flag_priv PNG_HFI_INIT = {
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"Private", "png.chunk.flag.private", FT_BOOLEAN, 32,
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TFS(&png_chunk_priv), 0x00200000, NULL, HFILL };
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static const true_false_string png_chunk_stc = {
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"This chunk is SAFE TO COPY",
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"This chunk is NOT safe to copy"
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};
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static header_field_info hfi_png_chunk_flag_stc PNG_HFI_INIT = {
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"Safe To Copy", "png.chunk.flag.stc", FT_BOOLEAN, 32,
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TFS(&png_chunk_stc), 0x00000020, NULL, HFILL };
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static header_field_info hfi_png_ihdr_width PNG_HFI_INIT = {
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"Width", "png.ihdr.width", FT_UINT32, BASE_DEC,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_ihdr_height PNG_HFI_INIT = {
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"Height", "png.ihdr.height", FT_UINT32, BASE_DEC,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_ihdr_bitdepth PNG_HFI_INIT = {
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"Bit Depth", "png.ihdr.bitdepth", FT_UINT8, BASE_DEC,
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NULL, 0, NULL, HFILL };
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static const value_string colour_type_vals[] = {
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{ 0, "Greyscale"},
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{ 2, "Truecolour"},
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{ 3, "Indexed-colour"},
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{ 4, "Greyscale with alpha"},
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{ 6, "Truecolour with alpha"},
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{ 0, NULL }
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};
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static header_field_info hfi_png_ihdr_colour_type PNG_HFI_INIT = {
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"Colour Type", "png.ihdr.colour_type", FT_UINT8, BASE_DEC,
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VALS(colour_type_vals), 0, NULL, HFILL };
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static const value_string compression_method_vals[] = {
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{ 0, "Deflate"},
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{ 0, NULL }
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};
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static header_field_info hfi_png_ihdr_compression_method PNG_HFI_INIT = {
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"Compression Method", "png.ihdr.compression_method", FT_UINT8, BASE_DEC,
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VALS(compression_method_vals), 0, NULL, HFILL };
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static const value_string filter_method_vals[] = {
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{ 0, "Adaptive"},
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{ 0, NULL }
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};
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static header_field_info hfi_png_ihdr_filter_method PNG_HFI_INIT = {
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"Filter Method", "png.ihdr.filter_method", FT_UINT8, BASE_DEC,
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VALS(filter_method_vals), 0, NULL, HFILL };
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static const value_string interlace_method_vals[] = {
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{ 0, "No interlace"},
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{ 1, "Adam7"},
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{ 0, NULL }
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};
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static header_field_info hfi_png_ihdr_interlace_method PNG_HFI_INIT = {
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"Interlace Method", "png.ihdr.interlace_method", FT_UINT8, BASE_DEC,
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VALS(interlace_method_vals), 0, NULL, HFILL };
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static header_field_info hfi_png_text_keyword PNG_HFI_INIT = {
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"Keyword", "png.text.keyword", FT_STRING, BASE_NONE,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_text_string PNG_HFI_INIT = {
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"String", "png.text.string", FT_STRING, BASE_NONE,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_time_year PNG_HFI_INIT = {
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"Year", "png.time.year", FT_UINT16, BASE_DEC,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_time_month PNG_HFI_INIT = {
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"Month", "png.time.month", FT_UINT8, BASE_DEC,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_time_day PNG_HFI_INIT = {
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"Day", "png.time.day", FT_UINT8, BASE_DEC,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_time_hour PNG_HFI_INIT = {
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"Hour", "png.time.hour", FT_UINT8, BASE_DEC,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_time_minute PNG_HFI_INIT = {
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"Minute", "png.time.minute", FT_UINT8, BASE_DEC,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_time_second PNG_HFI_INIT = {
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"Second", "png.time.second", FT_UINT8, BASE_DEC,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_phys_horiz PNG_HFI_INIT = {
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"Horizontal pixels per unit", "png.phys.horiz", FT_UINT32, BASE_DEC,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_phys_vert PNG_HFI_INIT = {
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"Vertical pixels per unit", "png.phys.vert", FT_UINT32, BASE_DEC,
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NULL, 0, NULL, HFILL };
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static const value_string phys_unit_vals[] = {
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{ 0, "Unit is unknown"},
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{ 1, "Unit is METRE"},
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{ 0, NULL }
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};
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static header_field_info hfi_png_phys_unit PNG_HFI_INIT = {
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"Unit", "png.phys.unit", FT_UINT8, BASE_DEC,
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VALS(phys_unit_vals), 0, NULL, HFILL };
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static header_field_info hfi_png_bkgd_palette_index PNG_HFI_INIT = {
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"Palette Index", "png.bkgd.palette_index", FT_UINT8, BASE_DEC,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_bkgd_greyscale PNG_HFI_INIT = {
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"Greyscale", "png.bkgd.greyscale", FT_UINT16, BASE_HEX,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_bkgd_red PNG_HFI_INIT = {
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"Red", "png.bkgd.red", FT_UINT16, BASE_HEX,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_bkgd_green PNG_HFI_INIT = {
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"Green", "png.bkgd.green", FT_UINT16, BASE_HEX,
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NULL, 0, NULL, HFILL };
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static header_field_info hfi_png_bkgd_blue PNG_HFI_INIT = {
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"Blue", "png.bkgd.blue", FT_UINT16, BASE_HEX,
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NULL, 0, NULL, HFILL };
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static gint ett_png = -1;
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static gint ett_png_chunk = -1;
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static gint ett_png_chunk_item = -1;
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static dissector_handle_t png_handle;
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static void
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dissect_png_ihdr(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
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{
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proto_tree_add_item(tree, &hfi_png_ihdr_width, tvb, 0, 4, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree, &hfi_png_ihdr_height, tvb, 4, 4, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree, &hfi_png_ihdr_bitdepth, tvb, 8, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree, &hfi_png_ihdr_colour_type, tvb, 9, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree, &hfi_png_ihdr_compression_method, tvb, 10, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree, &hfi_png_ihdr_filter_method, tvb, 11, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree, &hfi_png_ihdr_interlace_method, tvb, 12, 1, ENC_BIG_ENDIAN);
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}
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static void
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dissect_png_text(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
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{
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int offset=1;
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/* find the null that separates keyword and text string */
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while(1){
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if(!tvb_get_guint8(tvb, offset)){
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break;
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}
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offset++;
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}
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proto_tree_add_item(tree, &hfi_png_text_keyword, tvb, 0, offset, ENC_ASCII|ENC_NA);
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offset++;
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proto_tree_add_item(tree, &hfi_png_text_string, tvb, offset, tvb_length_remaining(tvb, offset), ENC_ASCII|ENC_NA);
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}
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static void
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dissect_png_time(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
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{
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proto_tree_add_item(tree, &hfi_png_time_year, tvb, 0, 2, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree, &hfi_png_time_month, tvb, 2, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree, &hfi_png_time_day, tvb, 3, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree, &hfi_png_time_hour, tvb, 4, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree, &hfi_png_time_minute, tvb, 5, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree, &hfi_png_time_second, tvb, 6, 1, ENC_BIG_ENDIAN);
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}
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static void
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dissect_png_phys(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
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{
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proto_tree_add_item(tree, &hfi_png_phys_horiz, tvb, 0, 4, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree, &hfi_png_phys_vert, tvb, 4, 4, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree, &hfi_png_phys_unit, tvb, 8, 1, ENC_BIG_ENDIAN);
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}
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static void
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dissect_png_bkgd(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
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{
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switch(tvb_reported_length(tvb)){
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case 1: /* colour type 3 */
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proto_tree_add_item(tree, &hfi_png_bkgd_palette_index, tvb, 0, 1, ENC_BIG_ENDIAN);
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break;
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case 2: /* colour type 0, 4 */
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proto_tree_add_item(tree, &hfi_png_bkgd_greyscale, tvb, 0, 2, ENC_BIG_ENDIAN);
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break;
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case 6: /* colour type 2, 6 */
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proto_tree_add_item(tree, &hfi_png_bkgd_red, tvb, 0, 2, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree, &hfi_png_bkgd_green, tvb, 2, 2, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree, &hfi_png_bkgd_blue, tvb, 4, 2, ENC_BIG_ENDIAN);
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break;
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}
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}
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typedef struct _chunk_dissector_t {
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guint32 type;
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const char *name;
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void (*dissector)(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
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} chunk_dissector_t;
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static chunk_dissector_t chunk_table[] = {
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{ 0x49484452, "Image Header", dissect_png_ihdr }, /* IHDR */
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{ 0x624b4744, "Background colour", dissect_png_bkgd }, /* bKGD */
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{ 0x70485973, "Physical pixel dimensions",
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dissect_png_phys }, /* pHYs */
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{ 0x74455874, "Textual data", dissect_png_text }, /* tEXt */
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{ 0x74494d45, "Image last-modification time",
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dissect_png_time }, /* tIME */
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{ 0x49454e44, "Image Trailer", NULL }, /* IEND */
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{ 0, NULL, NULL }
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};
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static gint
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dissect_png(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *data _U_)
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{
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proto_tree *tree = NULL;
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proto_item *ti;
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int offset=0;
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/* http://libpng.org/pub/png/spec/1.2/PNG-Structure.html#PNG-file-signature */
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static const guint8 magic[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
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if (tvb_length(tvb) < 20)
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return 0;
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if (tvb_memeql(tvb, 0, magic, sizeof(magic)) != 0)
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return 0;
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col_append_str(pinfo->cinfo, COL_INFO, " (PNG)");
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if(parent_tree){
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ti=proto_tree_add_item(parent_tree, hfi_png, tvb, offset, -1, ENC_NA);
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tree=proto_item_add_subtree(ti, ett_png);
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}
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proto_tree_add_item(tree, &hfi_png_signature, tvb, offset, 8, ENC_NA);
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offset+=8;
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while(tvb_reported_length_remaining(tvb, offset) > 0){
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proto_tree *chunk_tree=NULL;
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proto_item *it=NULL;
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guint32 len, type;
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chunk_dissector_t *cd;
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char str[5];
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len=tvb_get_ntohl(tvb, offset);
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type=tvb_get_ntohl(tvb, offset+4);
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str[0]=tvb_get_guint8(tvb, offset+4);
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str[1]=tvb_get_guint8(tvb, offset+5);
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str[2]=tvb_get_guint8(tvb, offset+6);
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str[3]=tvb_get_guint8(tvb, offset+7);
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str[4]=0;
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if(tree){
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it=proto_tree_add_text(tree, tvb, offset, offset+8+len+4, "%s", str);
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chunk_tree=proto_item_add_subtree(it, ett_png_chunk);
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}
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proto_tree_add_item(chunk_tree, &hfi_png_chunk_len, tvb, offset, 4, ENC_BIG_ENDIAN);
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offset+=4;
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it=proto_tree_add_item(chunk_tree, &hfi_png_chunk_type, tvb, offset, 4, ENC_ASCII|ENC_NA);
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proto_tree_add_item(chunk_tree, &hfi_png_chunk_flag_anc, tvb, offset, 4, ENC_BIG_ENDIAN);
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proto_tree_add_item(chunk_tree, &hfi_png_chunk_flag_priv, tvb, offset, 4, ENC_BIG_ENDIAN);
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proto_tree_add_item(chunk_tree, &hfi_png_chunk_flag_stc, tvb, offset, 4, ENC_BIG_ENDIAN);
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offset+=4;
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if (len >= 1000000000)
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THROW(ReportedBoundsError);
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cd=&chunk_table[0];
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while(1){
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if(cd->type==0){
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cd=NULL;
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break;
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}
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if(cd->type==type){
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break;
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}
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cd++;
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}
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if(chunk_tree){
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proto_item_append_text(chunk_tree, " %s", cd?cd->name:"(don't know how to dissect this)");
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}
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if(!cd){
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proto_tree_add_item(chunk_tree, &hfi_png_chunk_data, tvb, offset, len, ENC_NA);
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} else {
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if(cd->dissector){
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tvbuff_t *next_tvb;
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proto_tree *cti=NULL;
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next_tvb=tvb_new_subset(tvb, offset, MIN(tvb_length_remaining(tvb, offset), (int)len), len);
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if(it){
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cti=proto_item_add_subtree(it, ett_png_chunk_item);
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}
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cd->dissector(next_tvb, pinfo, cti);
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}
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}
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offset+=len;
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proto_tree_add_item(chunk_tree, &hfi_png_chunk_crc, tvb, offset, 4, ENC_BIG_ENDIAN);
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offset+=4;
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}
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return offset;
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}
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void
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proto_register_png(void)
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{
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#ifndef HAVE_HFI_SECTION_INIT
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static header_field_info *hfi[] =
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{
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&hfi_png_signature,
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&hfi_png_chunk_type,
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&hfi_png_chunk_data,
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&hfi_png_chunk_len,
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&hfi_png_chunk_crc,
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&hfi_png_chunk_flag_anc,
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&hfi_png_chunk_flag_priv,
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&hfi_png_chunk_flag_stc,
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&hfi_png_ihdr_width,
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&hfi_png_ihdr_height,
|
|
&hfi_png_ihdr_bitdepth,
|
|
&hfi_png_ihdr_colour_type,
|
|
&hfi_png_ihdr_compression_method,
|
|
&hfi_png_ihdr_filter_method,
|
|
&hfi_png_ihdr_interlace_method,
|
|
&hfi_png_text_keyword,
|
|
&hfi_png_text_string,
|
|
&hfi_png_time_year,
|
|
&hfi_png_time_month,
|
|
&hfi_png_time_day,
|
|
&hfi_png_time_hour,
|
|
&hfi_png_time_minute,
|
|
&hfi_png_time_second,
|
|
&hfi_png_phys_horiz,
|
|
&hfi_png_phys_vert,
|
|
&hfi_png_phys_unit,
|
|
&hfi_png_bkgd_palette_index,
|
|
&hfi_png_bkgd_greyscale,
|
|
&hfi_png_bkgd_red,
|
|
&hfi_png_bkgd_green,
|
|
&hfi_png_bkgd_blue,
|
|
};
|
|
#endif
|
|
|
|
static gint *ett[] =
|
|
{
|
|
&ett_png,
|
|
&ett_png_chunk,
|
|
&ett_png_chunk_item,
|
|
};
|
|
|
|
int proto_png;
|
|
|
|
proto_png = proto_register_protocol("Portable Network Graphics","PNG","png");
|
|
hfi_png = proto_registrar_get_nth(proto_png);
|
|
|
|
proto_register_fields(proto_png, hfi, array_length(hfi));
|
|
proto_register_subtree_array(ett, array_length(ett));
|
|
|
|
png_handle = new_register_dissector("png", dissect_png, proto_png);
|
|
}
|
|
|
|
static gboolean dissect_png_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
|
|
{
|
|
return dissect_png(tvb, pinfo, tree, NULL) > 0;
|
|
}
|
|
|
|
void
|
|
proto_reg_handoff_png(void)
|
|
{
|
|
dissector_add_string("media_type", "image/png", png_handle);
|
|
heur_dissector_add("http", dissect_png_heur, hfi_png->id);
|
|
heur_dissector_add("wtap_file", dissect_png_heur, hfi_png->id);
|
|
}
|