// // info.h: metadata extraction utilities // // Copyright (c) 2021 - 2023, Přemysl Eric Janouch // // Permission to use, copy, modify, and/or distribute this software for any // purpose with or without fee is hereby granted. // // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES // WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF // MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY // SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES // WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION // OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN // CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. // #include #include #include #include // --- TIFF/Exif --------------------------------------------------------------- #include "tiff-tables.h" #include "tiffer.h" // TODO(p): Consider if these can't be inlined into `tiff_entries`. static struct { uint16_t tag; struct tiff_entry *entries; } tiff_subifds[] = { {330, tiff_entries}, // SubIFDs {34665, exif_entries}, // Exif IFD Pointer {34853, exif_gps_entries}, // GPS Info IFD Pointer {40965, exif_interoperability_entries}, // Interoperability IFD Pointer {} }; // --- Utilities --------------------------------------------------------------- #define u64be tiffer_u64be #define u32be tiffer_u32be #define u16be tiffer_u16be #define u64le tiffer_u64le #define u32le tiffer_u32le #define u16le tiffer_u16le static char * binhex(const uint8_t *data, size_t len) { static const char *alphabet = "0123456789abcdef"; char *buf = calloc(1, len * 2 + 1), *p = buf; for (size_t i = 0; i < len; i++) { *p++ = alphabet[data[i] >> 4]; *p++ = alphabet[data[i] & 0xF]; } return buf; } // --- Analysis ---------------------------------------------------------------- static jv add_to_subarray(jv o, const char *key, jv value) { // Invalid values are not allocated, and we use up any valid one. // Beware that jv_get() returns jv_null() rather than jv_invalid(). // Also, the header comment is lying, jv_is_valid() doesn't unreference. jv a = jv_object_get(jv_copy(o), jv_string(key)); return jv_set(o, jv_string(key), jv_is_valid(a) ? jv_array_append(a, value) : JV_ARRAY(value)); } static jv add_warning(jv o, const char *message) { return add_to_subarray(o, "warnings", jv_string(message)); } static jv add_error(jv o, const char *message) { return jv_object_set(o, jv_string("error"), jv_string(message)); } // Forward declaration. static jv parse_jpeg(jv o, const uint8_t *p, size_t len); // --- Exif -------------------------------------------------------------------- static jv parse_exif_ifd(struct tiffer *T, const struct tiff_entry *info); static bool parse_exif_subifds_entry(const struct tiffer *T, const struct tiffer_entry *entry, struct tiffer *subT) { int64_t offset = 0; return tiffer_integer(T, entry, &offset) && offset >= 0 && offset <= UINT32_MAX && tiffer_subifd(T, offset, subT); } static jv parse_exif_subifds(const struct tiffer *T, struct tiffer_entry *entry, struct tiff_entry *info) { struct tiffer subT = {}; if (!parse_exif_subifds_entry(T, entry, &subT)) return jv_null(); jv a = jv_array(); do a = jv_array_append(a, parse_exif_ifd(&subT, info)); while (tiffer_next_ifd(&subT)); // The chain should correspond to the values in the entry (see TIFF // Technical Note 1: "the NextIFD value of Child #1 must point to Child #2, // and so on"), but at least some Nikon NEFs do not follow this rule. if (jv_array_length(jv_copy(a)) == 1) { while (tiffer_next_value(entry) && parse_exif_subifds_entry(T, entry, &subT)) a = jv_array_append(a, parse_exif_ifd(&subT, info)); } return a; } // Implemented partially, out of curiosity--it is not particularly useful, // because there is a ton more parsing to do here. static bool parse_exif_makernote(jv *v, const struct tiffer_entry *entry) { if (!getenv("INFO_MAKERNOTE") || entry->tag != Exif_MakerNote || entry->type != TIFFER_UNDEFINED) return false; struct tiffer T = {}; if (entry->remaining_count >= 16 && !memcmp(entry->p, "Nikon\x00\x02", 7) && tiffer_init(&T, entry->p + 10, entry->remaining_count - 10) && tiffer_next_ifd(&T)) { *v = parse_exif_ifd(&T, NULL); return true; } if (entry->remaining_count >= 16 && !memcmp(entry->p, "Apple iOS\x00\x00\x01MM", 14)) { T.un = &tiffer_unbe; T.begin = T.p = entry->p + 14; T.end = entry->p + entry->remaining_count - 14; T.remaining_fields = 0; struct tiffer subT = {}; if (tiffer_subifd(&T, 0, &subT)) { *v = parse_exif_ifd(&subT, NULL); return true; } } return false; } static jv parse_exif_ascii(struct tiffer_entry *entry) { // Adobe XMP Specification Part 3: Storage in Files, 2020/1, 2.4.2 // The text may in practice contain any 8-bit encoding, but likely UTF-8. // TODO(p): Validate UTF-8, and assume Latin 1 if unsuccessful. jv a = jv_array(); uint8_t *nul = 0; while ((nul = memchr(entry->p, 0, entry->remaining_count))) { size_t len = nul - entry->p; a = jv_array_append(a, jv_string_sized((const char *) entry->p, len)); entry->remaining_count -= len + 1; entry->p += len + 1; } // Trailing NULs are required, but let's extract everything. if (entry->remaining_count) { a = jv_array_append(a, jv_string_sized((const char *) entry->p, entry->remaining_count)); } return a; } static jv parse_exif_undefined(struct tiffer_entry *entry) { // Sometimes, it can be ASCII, but the safe bet is to hex-encode it. char *buf = binhex(entry->p, entry->remaining_count); jv s = jv_string(buf); free(buf); return s; } static jv parse_exif_value(const struct tiff_value *values, double real) { if (values) { for (; values->name; values++) if (values->value == real) return jv_string(values->name); } return jv_number(real); } static jv parse_exif_extract_sole_array_element(jv a) { return jv_array_length(jv_copy(a)) == 1 ? jv_array_get(a, 0) : a; } static jv parse_exif_entry(jv o, const struct tiffer *T, struct tiffer_entry *entry, const struct tiff_entry *info) { const struct tiff_entry *info_begin = info; static struct tiff_entry empty[] = {{}}; if (!info) info = empty; for (; info->name; info++) if (info->tag == entry->tag) break; struct tiff_entry *subentries = NULL; for (size_t i = 0; tiff_subifds[i].tag; i++) if (tiff_subifds[i].tag == entry->tag) subentries = tiff_subifds[i].entries; jv v = jv_true(); double real = 0; if (!entry->remaining_count) { v = jv_null(); } else if (entry->type == TIFFER_IFD || subentries) { v = parse_exif_subifds(T, entry, subentries); } else if (entry->type == TIFFER_ASCII) { v = parse_exif_extract_sole_array_element(parse_exif_ascii(entry)); } else if (info_begin == exif_entries && parse_exif_makernote(&v, entry)) { // Already processed. } else if (entry->type == TIFFER_UNDEFINED && !info->values) { // Several Exif entries of UNDEFINED type contain single-byte numbers. v = parse_exif_undefined(entry); } else if (info_begin == tiff_entries && entry->tag == TIFF_XMP && (entry->type == TIFFER_UNDEFINED || entry->type == TIFFER_BYTE)) { v = jv_string_sized((const char *) entry->p, entry->remaining_count); } else if (tiffer_real(T, entry, &real)) { v = jv_array(); do v = jv_array_append(v, parse_exif_value(info->values, real)); while (tiffer_next_value(entry) && tiffer_real(T, entry, &real)); v = parse_exif_extract_sole_array_element(v); } if (info->name) return jv_set(o, jv_string(info->name), v); return jv_set(o, jv_string_fmt("%u", entry->tag), v); } static jv parse_exif_ifd(struct tiffer *T, const struct tiff_entry *info) { int64_t compression = 0, jpeg = 0, jpeg_length = 0, strip_offsets = 0, strip_byte_counts = 0; jv ifd = jv_object(); struct tiffer_entry entry = {}; while (tiffer_next_entry(T, &entry)) { switch (entry.tag) { case TIFF_Compression: tiffer_integer(T, &entry, &compression); break; case TIFF_JPEGInterchangeFormat: tiffer_integer(T, &entry, &jpeg); break; case TIFF_JPEGInterchangeFormatLength: tiffer_integer(T, &entry, &jpeg_length); break; case TIFF_StripOffsets: tiffer_integer(T, &entry, &strip_offsets); break; case TIFF_StripByteCounts: tiffer_integer(T, &entry, &strip_byte_counts); break; } ifd = parse_exif_entry(ifd, T, &entry, info); } // This is how Exif specifies it, which doesn't follow TIFF 6.0. // Also support CR2 IFD1, which isn't tagged with compression at all. if (info == tiff_entries && /* compression == TIFF_Compression_JPEG && */ jpeg > 0 && jpeg_length > 0 && jpeg + jpeg_length <= (T->end - T->begin)) { ifd = jv_set(ifd, jv_string("JPEG image data"), parse_jpeg( jv_object(), T->begin + jpeg, jpeg_length)); } // As specified by DRAFT TIFF Technical Note 2 + TIFFphotoshop.pdf. // Theoretically, there may be more strips, but this is not expected. // Also support CR2 IFD0, which is tagged with the "wrong" compression. if (info == tiff_entries && (compression == TIFF_Compression_JPEGDatastream || compression == TIFF_Compression_JPEG) && strip_offsets > 0 && strip_byte_counts > 0 && strip_offsets + strip_byte_counts <= (T->end - T->begin)) { ifd = jv_set(ifd, jv_string("JPEG image data"), parse_jpeg( jv_object(), T->begin + strip_offsets, strip_byte_counts)); } return ifd; } static jv parse_exif(jv o, const uint8_t *p, size_t len) { struct tiffer T = {}; if (!tiffer_init(&T, p, len)) return add_warning(o, "invalid Exif"); while (tiffer_next_ifd(&T)) o = add_to_subarray(o, "Exif", parse_exif_ifd(&T, tiff_entries)); return o; } static bool detect_tiff(const uint8_t *p, size_t len) { return tiffer_init(&(struct tiffer) {}, p, len); } // TODO(p): Photoshop data and ICC profiles also have their tag in TIFF, // they're not currently processed. static jv parse_tiff(jv o, const uint8_t *p, size_t len) { struct tiffer T = {}; if (!tiffer_init(&T, p, len)) return add_warning(o, "invalid TIFF"); while (tiffer_next_ifd(&T)) o = add_to_subarray(o, "TIFF", parse_exif_ifd(&T, tiff_entries)); return o; } // --- Photoshop Image Resources ----------------------------------------------- // Adobe XMP Specification Part 3: Storage in Files, 2020/1, 1.1.3 + 3.1.3 // https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/ // Unless otherwise noted, the descriptions are derived from the above document. static struct { uint16_t id; const char *description; } psir_descriptions[] = { {1000, "Number of channels, rows, columns, depth, mode"}, {1001, "Macintosh print manager print info record"}, {1002, "Macintosh page format information"}, {1003, "Indexed color table"}, {1005, "Resolution information"}, {1006, "Names of alpha channels (Pascal strings)"}, {1007, "Display information"}, {1008, "Caption (Pascal string)"}, // XMP Part 3 3.3.3 {1009, "Border information"}, {1010, "Background color"}, {1011, "Print flags"}, {1012, "Grayscale and multichannel halftoning information"}, {1013, "Color halftoning information"}, {1014, "Duotone halftoning information"}, {1015, "Grayscale and multichannel transfer function"}, {1016, "Color transfer functions"}, {1017, "Duotone transfer functions"}, {1018, "Duotone image information"}, {1019, "Effective B/W values for the dot range"}, {1020, "Caption"}, // XMP Part 3 3.3.3 {1021, "EPS options"}, {1022, "Quick Mask information"}, {1023, "(Obsolete)"}, {1024, "Layer state information"}, {1025, "Working path (not saved)"}, {1026, "Layers group information"}, {1027, "(Obsolete)"}, {1028, "IPTC DataSets"}, // XMP Part 3 3.3.3 {1029, "Image mode for raw format files"}, {1030, "JPEG quality"}, {1032, "Grid and guides information"}, {1033, "Thumbnail resource"}, {1034, "Copyright flag"}, {1035, "Copyright information URL"}, // XMP Part 3 3.3.3 {1036, "Thumbnail resource"}, {1037, "Global lighting angle for effects layer"}, {1038, "Color samplers information"}, {1039, "ICC profile"}, {1040, "Watermark"}, {1041, "ICC untagged profile flag"}, {1042, "Effects visible flag"}, {1043, "Spot halftone"}, {1044, "Document-specific IDs seed number"}, {1045, "Unicode alpha names"}, {1046, "Indexed color table count"}, {1047, "Transparent color index"}, {1049, "Global altitude"}, {1050, "Slices"}, {1051, "Workflow URL"}, {1052, "Jump To XPEP"}, {1053, "Alpha identifiers"}, {1054, "URL list"}, {1057, "Version info"}, {1058, "Exif metadata 1"}, {1059, "Exif metadata 3"}, {1060, "XMP metadata"}, {1061, "MD5 digest of IPTC data"}, // XMP Part 3 3.3.3 {1062, "Print scale"}, {1064, "Pixel aspect ratio"}, {1065, "Layer comps"}, {1066, "Alternate duotone colors"}, {1067, "Alternate spot colors"}, {1069, "Layer selection IDs"}, {1070, "HDR toning information"}, {1071, "Print info"}, {1072, "Layer group(s) enabled ID"}, {1073, "Color samplers"}, {1074, "Measurement scale"}, {1075, "Timeline information"}, {1076, "Sheet disclosure"}, {1077, "Display information to support floating point colors"}, {1078, "Onion skins"}, {1080, "Count information"}, {1082, "Print information"}, {1083, "Print style"}, {1084, "Macintosh NSPrintInfo"}, {1085, "Windows DEVMODE"}, {1086, "Autosave file path"}, {1087, "Autosave format"}, {1088, "Path selection state"}, // {2000-2997, "Saved paths"}, {2999, "Name of clipping path"}, {3000, "Origin path information"}, // {4000-4999, "Plug-in resource"}, {7000, "Image Ready variables"}, {7001, "Image Ready data sets"}, {7002, "Image Ready default selected state"}, {7003, "Image Ready 7 rollover expanded state"}, {7004, "Image Ready rollover expanded state"}, {7005, "Image Ready save layer settings"}, {7006, "Image Ready version"}, {8000, "Lightroom workflow"}, {10000, "Print flags"}, {} }; static jv process_psir_thumbnail(jv res, const uint8_t *data, size_t len) { uint32_t format_number = u32be(data + 0); uint32_t compressed_size = u32be(data + 20); // TODO(p): Recurse into the thumbnail if it's a JPEG. jv format = jv_number(format_number); switch (format_number) { break; case 0: format = jv_string("kJpegRGB"); break; case 1: format = jv_string("kRawRGB"); } res = jv_object_merge(res, JV_OBJECT( jv_string("Format"), format, jv_string("Width"), jv_number(u32be(data + 4)), jv_string("Height"), jv_number(u32be(data + 8)), jv_string("Stride"), jv_number(u32be(data + 12)), jv_string("TotalSize"), jv_number(u32be(data + 16)), jv_string("CompressedSize"), jv_number(compressed_size), jv_string("BitsPerPixel"), jv_number(u16be(data + 24)), jv_string("Planes"), jv_number(u16be(data + 26)) )); if (28 + compressed_size <= len) { char *buf = binhex(data + 28, compressed_size); res = jv_set(res, jv_string("Data"), jv_string(buf)); free(buf); } return res; } static const char * process_iptc_dataset(jv *a, const uint8_t **p, size_t len) { const uint8_t *header = *p; if (len < 5) return "unexpected end of IPTC data"; if (*header != 0x1c) return "invalid tag marker"; uint8_t record = header[1]; uint8_t dataset = header[2]; uint16_t byte_count = header[3] << 8 | header[4]; // TODO(p): Although highly unlikely to appear, we could decode it. if (byte_count & 0x8000) return "unsupported extended DataSet"; if (len - 5 < byte_count) return "data overrun"; char *buf = binhex(header + 5, byte_count); *p += 5 + byte_count; *a = jv_array_append(*a, JV_OBJECT( jv_string("DataSet"), jv_string_fmt("%u:%u", record, dataset), jv_string("Data"), jv_string(buf) )); free(buf); return NULL; } static jv process_psir_iptc(jv res, const uint8_t *data, size_t len) { // https://iptc.org/standards/iim/ // https://iptc.org/std/IIM/4.2/specification/IIMV4.2.pdf jv a = jv_array(); const uint8_t *end = data + len; while (data < end) { const char *err = process_iptc_dataset(&a, &data, end - data); if (err) { a = jv_array_append(a, jv_string(err)); break; } } return jv_set(res, jv_string("DataSets"), a); } static jv process_psir(jv o, uint16_t resource_id, const char *name, const uint8_t *data, size_t len) { const char *description = NULL; if (resource_id >= 2000 && resource_id <= 2997) description = "Saved paths"; if (resource_id >= 4000 && resource_id <= 4999) description = "Plug-in resource"; for (size_t i = 0; psir_descriptions[i].id; i++) if (psir_descriptions[i].id == resource_id) description = psir_descriptions[i].description; jv res = JV_OBJECT( jv_string("name"), jv_string(name), jv_string("id"), jv_number(resource_id), jv_string("description"), description ? jv_string(description) : jv_null(), jv_string("size"), jv_number(len) ); // Both are thumbnails, older is BGR, newer is RGB. if ((resource_id == 1033 || resource_id == 1036) && len >= 28) res = process_psir_thumbnail(res, data, len); if (resource_id == 1028) res = process_psir_iptc(res, data, len); return add_to_subarray(o, "PSIR", res); } static jv parse_psir_block(jv o, const uint8_t *p, size_t len, size_t *advance) { *advance = 0; if (len < 8 || memcmp(p, "8BIM", 4)) return add_warning(o, "bad PSIR block header"); uint16_t resource_id = u16be(p + 4); uint8_t name_len = p[6]; const uint8_t *name = &p[7]; // Add one byte for the Pascal-ish string length prefix, // then another one for padding to make the length even. size_t name_len_full = (name_len + 2) & ~1U; size_t resource_len_offset = 6 + name_len_full, header_len = resource_len_offset + 4; if (len < header_len) return add_warning(o, "bad PSIR block header"); uint32_t resource_len = u32be(p + resource_len_offset); size_t resource_len_padded = (resource_len + 1) & ~1U; if (resource_len_padded < resource_len || len < header_len + resource_len_padded) return add_warning(o, "runaway PSIR block"); char *cname = calloc(1, name_len_full); strncpy(cname, (const char *) name, name_len); o = process_psir(o, resource_id, cname, p + header_len, resource_len); free(cname); *advance = header_len + resource_len_padded; return o; } static jv parse_psir(jv o, const uint8_t *p, size_t len) { if (len == 0) return add_warning(o, "empty PSIR data"); size_t advance = 0; while (len && (o = parse_psir_block(o, p, len, &advance), advance)) { p += advance; len -= advance; } return o; } // --- ICC profiles ------------------------------------------------------------ // v2 https://www.color.org/ICC_Minor_Revision_for_Web.pdf // v4 https://www.color.org/specification/ICC1v43_2010-12.pdf static jv parse_icc_mluc(jv o, const uint8_t *tag, uint32_t tag_length) { // v4 10.13 if (tag_length < 16) return add_warning(o, "invalid ICC 'mluc' structure length"); uint32_t count = u32be(tag + 8); if (count == 0) return add_warning(o, "unnamed ICC profile"); // There is no particularly good reason for us to iterate, take the first. const uint8_t *record = tag + 16 /* + i * u32be(tag + 12) */; uint32_t len = u32be(&record[4]); uint32_t off = u32be(&record[8]); if (off + len > tag_length) return add_warning(o, "invalid ICC 'mluc' structure record"); // Blindly assume simple ASCII, ensure NUL-termination. char name[len], *p = name; for (uint32_t i = 0; i < len / 2; i++) *p++ = tag[off + i * 2 + 1]; *p++ = 0; return jv_set(o, jv_string("ICC"), JV_OBJECT(jv_string("name"), jv_string(name), jv_string("version"), jv_number(4))); } static jv parse_icc_desc(jv o, const uint8_t *profile, size_t profile_len, uint32_t tag_offset, uint32_t tag_length) { const uint8_t *tag = profile + tag_offset; if (tag_offset + tag_length > profile_len) return add_warning(o, "unexpected end of ICC profile"); if (tag_length < 4) return add_warning(o, "invalid ICC tag structure length"); // v2 6.5.17 uint32_t sig = u32be(tag); if (sig == 0x6D6C7563 /* mluc */) return parse_icc_mluc(o, profile + tag_offset, tag_length); if (sig != 0x64657363 /* desc */) return add_warning(o, "invalid ICC 'desc' structure signature"); if (tag_length < 12) return add_warning(o, "invalid ICC 'desc' structure length"); uint32_t count = u32be(tag + 8); if (tag_length < 12 + count) return add_warning(o, "invalid ICC 'desc' structure length"); // Double-ensure a trailing NUL byte. char name[count + 1]; memcpy(name, tag + 12, count); name[count] = 0; return jv_set(o, jv_string("ICC"), JV_OBJECT(jv_string("name"), jv_string(name), jv_string("version"), jv_number(2))); } static jv parse_icc(jv o, const uint8_t *profile, size_t profile_len) { // v2 6, v4 7 if (profile_len < 132) return add_warning(o, "ICC profile too short"); if (u32be(profile) != profile_len) return add_warning(o, "ICC profile size mismatch"); // TODO(p): May decode more of the header fields, and validate them. // Need to check both v2 and v4, this is all fairly annoying. uint32_t count = u32be(profile + 128); if (132 + count * 12 > profile_len) return add_warning(o, "unexpected end of ICC profile"); for (uint32_t i = 0; i < count; i++) { const uint8_t *entry = profile + 132 + i * 12; uint32_t sig = u32be(&entry[0]); uint32_t off = u32be(&entry[4]); uint32_t len = u32be(&entry[8]); // v2 6.4.32, v4 9.2.41 if (sig == 0x64657363 /* desc */) return parse_icc_desc(o, profile, profile_len, off, len); } // The description is required, so this should be unreachable. return jv_set(o, jv_string("ICC"), jv_bool(true)); } // --- Multi-Picture Format ---------------------------------------------------- static uint32_t parse_mpf_mpentry(jv *a, const uint8_t *p, const struct tiffer *T) { uint32_t attrs = T->un->u32(p); uint32_t offset = T->un->u32(p + 8); uint32_t type_number = attrs & 0xFFFFFF; jv type = jv_number(type_number); switch (type_number) { break; case 0x030000: type = jv_string("Baseline MP Primary Image"); break; case 0x010001: type = jv_string("Large Thumbnail - VGA"); break; case 0x010002: type = jv_string("Large Thumbnail - Full HD"); break; case 0x020001: type = jv_string("Multi-Frame Image Panorama"); break; case 0x020002: type = jv_string("Multi-Frame Image Disparity"); break; case 0x020003: type = jv_string("Multi-Frame Image Multi-Angle"); break; case 0x000000: type = jv_string("Undefined"); } uint32_t format_number = (attrs >> 24) & 0x7; jv format = jv_number(format_number); if (format_number == 0) format = jv_string("JPEG"); *a = jv_array_append(*a, JV_OBJECT( jv_string("Individual Image Attribute"), JV_OBJECT( jv_string("Dependent Parent Image"), jv_bool((attrs >> 31) & 1), jv_string("Dependent Child Image"), jv_bool((attrs >> 30) & 1), jv_string("Representative Image"), jv_bool((attrs >> 29) & 1), jv_string("Reserved"), jv_number((attrs >> 27) & 0x3), jv_string("Image Data Format"), format, jv_string("MP Type Code"), type ), jv_string("Individual Image Size"), jv_number(T->un->u32(p + 4)), jv_string("Individual Image Data Offset"), jv_number(offset), jv_string("Dependent Image 1 Entry Number"), jv_number(T->un->u16(p + 12)), jv_string("Dependent Image 2 Entry Number"), jv_number(T->un->u16(p + 14)) )); // Don't report non-JPEGs, even though they're unlikely. return format_number == 0 ? offset : 0; } static jv parse_mpf_index_entry(jv o, uint32_t **offsets, const struct tiffer *T, struct tiffer_entry *entry) { // 5.2.3.3. MP Entry if (entry->tag != MPF_MPEntry || entry->type != TIFFER_UNDEFINED || entry->remaining_count % 16) { return parse_exif_entry(o, T, entry, mpf_entries); } uint32_t count = entry->remaining_count / 16; jv a = jv_array_sized(count); uint32_t *out = *offsets = calloc(sizeof *out, count + 1); for (uint32_t i = 0; i < count; i++) { // 5.2.3.3.3. Individual Image Data Offset uint32_t offset = parse_mpf_mpentry(&a, entry->p + i * 16, T); if (offset) *out++ = offset; } return jv_set(o, jv_string("MP Entry"), a); } static jv parse_mpf_index_ifd(uint32_t **offsets, struct tiffer *T) { jv ifd = jv_object(); struct tiffer_entry entry = {}; while (tiffer_next_entry(T, &entry)) ifd = parse_mpf_index_entry(ifd, offsets, T, &entry); return ifd; } static jv parse_mpf(jv o, const uint8_t ***individuals, const uint8_t *p, size_t len, const uint8_t *end) { struct tiffer T; if (!tiffer_init(&T, p, len) || !tiffer_next_ifd(&T)) return add_warning(o, "invalid MPF segment"); // First image: IFD0 is Index IFD, any IFD1 is Attribute IFD. // Other images: IFD0 is Attribute IFD, there is no Index IFD. uint32_t *offsets = NULL; if (!*individuals) { o = add_to_subarray(o, "MPF", parse_mpf_index_ifd(&offsets, &T)); if (!tiffer_next_ifd(&T)) goto out; } // This isn't optimal, but it will do. o = add_to_subarray(o, "MPF", parse_exif_ifd(&T, mpf_entries)); out: if (offsets) { size_t count = 0; for (const uint32_t *i = offsets; *i; i++) count++; free(*individuals); const uint8_t **out = *individuals = calloc(sizeof *out, count + 1); for (const uint32_t *i = offsets; *i; i++) { if (*i > end - p) o = add_warning(o, "MPF offset points past available data"); else *out++ = p + *i; } free(offsets); } return o; } // --- JPEG -------------------------------------------------------------------- // Because the JPEG file format is simple, just do it manually. // See: https://www.w3.org/Graphics/JPEG/itu-t81.pdf enum { TEM = 0x01, SOF0 = 0xC0, SOF1, SOF2, SOF3, DHT = 0xC4, SOF5, SOF6, SOF7, JPG = 0xC8, SOF9, SOF10, SOF11, DAC = 0xCC, SOF13, SOF14, SOF15, RST0 = 0xD0, RST1, RST2, RST3, RST4, RST5, RST6, RST7, SOI = 0xD8, EOI = 0xD9, SOS = 0xDA, DQT = 0xDB, DNL = 0xDC, DRI = 0xDD, DHP = 0xDE, EXP = 0xDF, APP0 = 0xE0, APP1, APP2, APP3, APP4, APP5, APP6, APP7, APP8, APP9, APP10, APP11, APP12, APP13, APP14, APP15, JPG0 = 0xF0, JPG1, JPG2, JPG3, JPG4, JPG5, JPG6, JPG7, JPG8, JPG9, JPG10, JPG11, JPG12, JPG13, COM = 0xFE }; // The rest is "RES (Reserved)", except for 0xFF (filler) and 0x00 (invalid). static const char *marker_ids[0xFF] = { [TEM] = "TEM", [SOF0] = "SOF0", [SOF1] = "SOF1", [SOF2] = "SOF2", [SOF3] = "SOF3", [DHT] = "DHT", [SOF5] = "SOF5", [SOF6] = "SOF6", [SOF7] = "SOF7", [JPG] = "JPG", [SOF9] = "SOF9", [SOF10] = "SOF10", [SOF11] = "SOF11", [DAC] = "DAC", [SOF13] = "SOF13", [SOF14] = "SOF14", [SOF15] = "SOF15", [RST0] = "RST0", [RST1] = "RST1", [RST2] = "RST2", [RST3] = "RST3", [RST4] = "RST4", [RST5] = "RST5", [RST6] = "RST6", [RST7] = "RST7", [SOI] = "SOI", [EOI] = "EOI", [SOS] = "SOS", [DQT] = "DQT", [DNL] = "DNL", [DRI] = "DRI", [DHP] = "DHP", [EXP] = "EXP", [APP0] = "APP0", [APP1] = "APP1", [APP2] = "APP2", [APP3] = "APP3", [APP4] = "APP4", [APP5] = "APP5", [APP6] = "APP6", [APP7] = "APP7", [APP8] = "APP8", [APP9] = "APP9", [APP10] = "APP10", [APP11] = "APP11", [APP12] = "APP12", [APP13] = "APP13", [APP14] = "APP14", [APP15] = "APP15", [JPG0] = "JPG0", [JPG1] = "JPG1", [JPG2] = "JPG2", [JPG3] = "JPG3", [JPG4] = "JPG4", [JPG5] = "JPG5", [JPG6] = "JPG6", [JPG7] = "JPG7", [JPG8] = "JPG8", [JPG9] = "JPG9", [JPG10] = "JPG10", [JPG11] = "JPG11", [JPG12] = "JPG12", [JPG13] = "JPG13", [COM] = "COM" }; // The rest is "RES (Reserved)", except for 0xFF (filler) and 0x00 (invalid). static const char *marker_descriptions[0xFF] = { [TEM] = "For temporary private use in arithmetic coding", [SOF0] = "Baseline DCT", [SOF1] = "Extended sequential DCT", [SOF2] = "Progressive DCT", [SOF3] = "Lossless (sequential)", [DHT] = "Define Huffman table(s)", [SOF5] = "Differential sequential DCT", [SOF6] = "Differential progressive DCT", [SOF7] = "Differential lossless (sequential)", [JPG] = "Reserved for JPEG extensions", [SOF9] = "Extended sequential DCT", [SOF10] = "Progressive DCT", [SOF11] = "Lossless (sequential)", [DAC] = "Define arithmetic coding conditioning(s)", [SOF13] = "Differential sequential DCT", [SOF14] = "Differential progressive DCT", [SOF15] = "Differential lossless (sequential)", [RST0] = "Restart with module 8 count 0", [RST1] = "Restart with module 8 count 1", [RST2] = "Restart with module 8 count 2", [RST3] = "Restart with module 8 count 3", [RST4] = "Restart with module 8 count 4", [RST5] = "Restart with module 8 count 5", [RST6] = "Restart with module 8 count 6", [RST7] = "Restart with module 8 count 7", [SOI] = "Start of image", [EOI] = "End of image", [SOS] = "Start of scan", [DQT] = "Define quantization table(s)", [DNL] = "Define number of lines", [DRI] = "Define restart interval", [DHP] = "Define hierarchical progression", [EXP] = "Expand reference component(s)", [APP0] = "Reserved for application segments, 0", [APP1] = "Reserved for application segments, 1", [APP2] = "Reserved for application segments, 2", [APP3] = "Reserved for application segments, 3", [APP4] = "Reserved for application segments, 4", [APP5] = "Reserved for application segments, 5", [APP6] = "Reserved for application segments, 6", [APP7] = "Reserved for application segments, 7", [APP8] = "Reserved for application segments, 8", [APP9] = "Reserved for application segments, 9", [APP10] = "Reserved for application segments, 10", [APP11] = "Reserved for application segments, 11", [APP12] = "Reserved for application segments, 12", [APP13] = "Reserved for application segments, 13", [APP14] = "Reserved for application segments, 14", [APP15] = "Reserved for application segments, 15", [JPG0] = "Reserved for JPEG extensions, 0", [JPG1] = "Reserved for JPEG extensions, 1", [JPG2] = "Reserved for JPEG extensions, 2", [JPG3] = "Reserved for JPEG extensions, 3", [JPG4] = "Reserved for JPEG extensions, 4", [JPG5] = "Reserved for JPEG extensions, 5", [JPG6] = "Reserved for JPEG extensions, 6", [JPG7] = "Reserved for JPEG extensions, 7", [JPG8] = "Reserved for JPEG extensions, 8", [JPG9] = "Reserved for JPEG extensions, 9", [JPG10] = "Reserved for JPEG extensions, 10", [JPG11] = "Reserved for JPEG extensions, 11", [JPG12] = "Reserved for JPEG extensions, 12", [JPG13] = "Reserved for JPEG extensions, 13", [COM] = "Comment", }; // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - struct data { bool ended; uint8_t *exif, *icc, *psir; size_t exif_len, icc_len, psir_len; int icc_sequence, icc_done; const uint8_t **mpf_individuals, **mpf_next; }; static void parse_append(uint8_t **buffer, size_t *buffer_len, const uint8_t *p, size_t len) { size_t buffer_longer = *buffer_len + len; *buffer = realloc(*buffer, buffer_longer); memcpy(*buffer + *buffer_len, p, len); *buffer_len = buffer_longer; } static const uint8_t * parse_marker(uint8_t marker, const uint8_t *p, const uint8_t *end, struct data *data, jv *o) { // Suspected: MJPEG? Undetected format recursion, e.g., thumbnails? // Found: Random metadata! Multi-Picture Format! if ((data->ended = marker == EOI)) { // TODO(p): Handle Exifs independently--flush the last one. if ((data->mpf_next || (data->mpf_next = data->mpf_individuals)) && *data->mpf_next) return *data->mpf_next++; if (p != end) *o = add_warning(*o, "trailing data"); } // These markers stand alone, not starting a marker segment. switch (marker) { case RST0: case RST1: case RST2: case RST3: case RST4: case RST5: case RST6: case RST7: *o = add_warning(*o, "unexpected restart marker"); // Fall-through case SOI: case EOI: case TEM: return p; } uint16_t length = p[0] << 8 | p[1]; const uint8_t *payload = p + 2; if ((p += length) > end) { *o = add_error(*o, "runaway marker segment"); return NULL; } switch (marker) { case SOF0: case SOF1: case SOF2: case SOF3: case SOF5: case SOF6: case SOF7: case SOF9: case SOF10: case SOF11: case SOF13: case SOF14: case SOF15: case DHP: // B.2.2 and B.3.2. // As per B.2.5, Y can be zero, then there needs to be a DNL segment. *o = add_to_subarray(*o, "info", JV_OBJECT( jv_string("type"), jv_string(marker_descriptions[marker]), jv_string("bits"), jv_number(payload[0]), jv_string("height"), jv_number(payload[1] << 8 | payload[2]), jv_string("width"), jv_number(payload[3] << 8 | payload[4]), jv_string("components"), jv_number(payload[5]) )); return p; } // See B.1.1.5, we can brute-force our way through the entropy-coded data. if (marker == SOS) { while (p + 2 <= end && (p[0] != 0xFF || p[1] < 0xC0 || p[1] > 0xFE || (p[1] >= RST0 && p[1] <= RST7))) p++; return p; } // "The interpretation is left to the application." if (marker == COM) { int superascii = 0; char *buf = calloc(3, p - payload), *bufp = buf; for (const uint8_t *q = payload; q < p; q++) { if (*q < 128) { *bufp++ = *q; } else { superascii++; *bufp++ = 0xC0 | (*q >> 6); *bufp++ = 0x80 | (*q & 0x3F); } } *bufp++ = 0; *o = add_to_subarray(*o, "comments", jv_string(buf)); free(buf); if (superascii) *o = add_warning(*o, "super-ASCII comments"); } // These mostly contain an ASCII string header, following JPEG FIF: // // "Application-specific APP0 marker segments are identified // by a zero terminated string which identifies the application // (not 'JFIF' or 'JFXX')." if (marker >= APP0 && marker <= APP15) { const uint8_t *nul = memchr(payload, 0, p - payload); int unprintable = !nul; if (nul) { for (const uint8_t *q = payload; q < nul; q++) unprintable += *q < 32 || *q >= 127; } *o = add_to_subarray(*o, "apps", unprintable ? jv_null() : jv_string((const char *) payload)); } // CIPA DC-007-2021 (Multi-Picture Format) 5.2 // https://www.cipa.jp/e/std/std-sec.html if (marker == APP2 && p - payload >= 8 && !memcmp(payload, "MPF\0", 4)) { payload += 4; *o = parse_mpf(*o, &data->mpf_individuals, payload, p - payload, end); } // CIPA DC-006 (Stereo Still Image Format for Digital Cameras) // TODO(p): Handle by properly skipping trailing data (use Stim offsets). // https://www.w3.org/Graphics/JPEG/jfif3.pdf if (marker == APP0 && p - payload >= 14 && !memcmp(payload, "JFIF\0", 5)) { payload += 5; jv units = jv_number(payload[2]); switch (payload[2]) { break; case 0: units = jv_null(); break; case 1: units = jv_string("DPI"); break; case 2: units = jv_string("dots per cm"); } // The rest is picture data. *o = add_to_subarray(*o, "JFIF", JV_OBJECT( jv_string("version"), jv_number(payload[0] * 100 + payload[1]), jv_string("units"), units, jv_string("density-x"), jv_number(payload[3] << 8 | payload[4]), jv_string("density-y"), jv_number(payload[5] << 8 | payload[6]), jv_string("thumbnail-w"), jv_number(payload[7]), jv_string("thumbnail-h"), jv_number(payload[8]) )); } if (marker == APP0 && p - payload >= 6 && !memcmp(payload, "JFXX\0", 5)) { payload += 5; jv extension = jv_number(payload[0]); switch (payload[0]) { break; case 0x10: extension = jv_string("JPEG thumbnail"); break; case 0x11: extension = jv_string("Paletted thumbnail"); break; case 0x13: extension = jv_string("RGB thumbnail"); } // The rest is picture data. *o = add_to_subarray(*o, "JFXX", JV_OBJECT(jv_string("extension"), extension)); } // https://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf 4.7.2 // Adobe XMP Specification Part 3: Storage in Files, 2020/1, 1.1.3 if (marker == APP1 && p - payload >= 6 && !memcmp(payload, "Exif\0", 5)) { payload += 6; if (payload[-1] != 0) *o = add_warning(*o, "weirdly padded Exif header"); if (data->exif) *o = add_warning(*o, "multiple Exif segments"); parse_append(&data->exif, &data->exif_len, payload, p - payload); } // https://www.color.org/specification/ICC1v43_2010-12.pdf B.4 if (marker == APP2 && p - payload >= 14 && !memcmp(payload, "ICC_PROFILE\0", 12) && !data->icc_done && payload[12] == ++data->icc_sequence && payload[13] >= payload[12]) { payload += 14; parse_append(&data->icc, &data->icc_len, payload, p - payload); data->icc_done = payload[-1] == data->icc_sequence; } // Adobe XMP Specification Part 3: Storage in Files, 2020/1, 1.1.3 + 3.1.3 // https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/ if (marker == APP13 && p - payload >= 14 && !memcmp(payload, "Photoshop 3.0\0", 14)) { payload += 14; parse_append(&data->psir, &data->psir_len, payload, p - payload); } // TODO(p): Extract all XMP segments. return p; } static bool detect_jpeg(const uint8_t *p, size_t len) { return len >= 2 && p[0] == 0xff && p[1] == SOI; } static jv parse_jpeg(jv o, const uint8_t *p, size_t len) { struct data data = {}; const uint8_t *end = p + len; jv markers = jv_array(); while (p) { // This is an expectable condition, use a simple warning. if (p + 2 > end) { if (!data.ended) o = add_warning(o, "unexpected EOF"); break; } if (*p++ != 0xFF || *p == 0) { if (!data.ended) o = add_error(o, "no marker found where one was expected"); break; } // Markers may be preceded by fill bytes. if (*p == 0xFF) { o = jv_object_set(o, jv_string("fillers"), jv_bool(true)); continue; } uint8_t marker = *p++; markers = jv_array_append(markers, jv_string(marker_ids[marker] ? marker_ids[marker] : "RES")); p = parse_marker(marker, p, end, &data, &o); } if (data.exif) { // TODO(p): Probably extend it until the end of the JPEG, // seeing as, e.g., thumbnail data can overflow into follow-up segments. o = parse_exif(o, data.exif, data.exif_len); free(data.exif); } if (data.icc) { if (data.icc_done) o = parse_icc(o, data.icc, data.icc_len); else o = add_warning(o, "bad ICC profile sequence"); free(data.icc); } if (data.psir) { o = parse_psir(o, data.psir, data.psir_len); free(data.psir); } free(data.mpf_individuals); return jv_set(o, jv_string("markers"), markers); }