1 /* Copyright 2015 the unarr project authors (see AUTHORS file).
2 License: LGPLv3 */
3
4 #include "rar.h"
5
rar_close(ar_archive * ar)6 static void rar_close(ar_archive *ar)
7 {
8 ar_archive_rar *rar = (ar_archive_rar *)ar;
9 free(rar->entry.name);
10 rar_clear_uncompress(&rar->uncomp);
11 }
12
rar_parse_entry(ar_archive * ar,off64_t offset)13 static bool rar_parse_entry(ar_archive *ar, off64_t offset)
14 {
15 ar_archive_rar *rar = (ar_archive_rar *)ar;
16 struct rar_header header;
17 struct rar_entry entry;
18 bool out_of_order = offset != ar->entry_offset_next;
19
20 if (!ar_seek(ar->stream, offset, SEEK_SET)) {
21 warn("Couldn't seek to offset %" PRIi64, offset);
22 return false;
23 }
24
25 for (;;) {
26 ar->entry_offset = ar_tell(ar->stream);
27 ar->entry_size_uncompressed = 0;
28
29 if (!rar_parse_header(ar, &header))
30 return false;
31
32 ar->entry_offset_next = ar->entry_offset + header.size + header.datasize;
33 if (ar->entry_offset_next < ar->entry_offset + header.size) {
34 warn("Integer overflow due to overly large data size");
35 return false;
36 }
37
38 switch (header.type) {
39 case TYPE_MAIN_HEADER:
40 if ((header.flags & MHD_PASSWORD)) {
41 warn("Encrypted archives aren't supported");
42 return false;
43 }
44 ar_skip(ar->stream, 6 /* reserved data */);
45 if ((header.flags & MHD_ENCRYPTVER)) {
46 log("MHD_ENCRYPTVER is set");
47 ar_skip(ar->stream, 1);
48 }
49 if ((header.flags & MHD_COMMENT))
50 log("MHD_COMMENT is set");
51 if (ar_tell(ar->stream) - ar->entry_offset > header.size) {
52 warn("Invalid RAR header size: %d", header.size);
53 return false;
54 }
55 rar->archive_flags = header.flags;
56 break;
57
58 case TYPE_FILE_ENTRY:
59 if (!rar_parse_header_entry(rar, &header, &entry))
60 return false;
61 if ((header.flags & LHD_PASSWORD))
62 warn("Encrypted entries will fail to uncompress");
63 if ((header.flags & LHD_DIRECTORY) == LHD_DIRECTORY) {
64 if (header.datasize == 0) {
65 log("Skipping directory entry \"%s\"", rar_get_name(ar));
66 break;
67 }
68 warn("Can't skip directory entries containing data");
69 }
70 if ((header.flags & (LHD_SPLIT_BEFORE | LHD_SPLIT_AFTER)))
71 warn("Splitting files isn't really supported");
72 ar->entry_size_uncompressed = (size_t)entry.size;
73 ar->entry_filetime = ar_conv_dosdate_to_filetime(entry.dosdate);
74 if (!rar->entry.solid || rar->entry.method == METHOD_STORE || out_of_order) {
75 rar_clear_uncompress(&rar->uncomp);
76 memset(&rar->solid, 0, sizeof(rar->solid));
77 }
78 else {
79 br_clear_leftover_bits(&rar->uncomp);
80 }
81
82 rar->solid.restart = rar->entry.solid && (out_of_order || !rar->solid.part_done);
83 rar->solid.part_done = !ar->entry_size_uncompressed;
84 rar->progress.data_left = (size_t)header.datasize;
85 rar->progress.bytes_done = 0;
86 rar->progress.crc = 0;
87
88 /* TODO: CRC checks don't always hold (claim in XADRARParser.m @readBlockHeader) */
89 if (!rar_check_header_crc(ar))
90 warn("Invalid header checksum @%" PRIi64, ar->entry_offset);
91 if (ar_tell(ar->stream) != ar->entry_offset + rar->entry.header_size) {
92 warn("Couldn't seek to offset %" PRIi64, ar->entry_offset + rar->entry.header_size);
93 return false;
94 }
95 return true;
96
97 case TYPE_NEWSUB:
98 log("Skipping newsub header @%" PRIi64, ar->entry_offset);
99 break;
100
101 case TYPE_END_OF_ARCHIVE:
102 ar->at_eof = true;
103 return false;
104
105 default:
106 log("Unknown RAR header type %02x", header.type);
107 break;
108 }
109
110 /* TODO: CRC checks don't always hold (claim in XADRARParser.m @readBlockHeader) */
111 if (!rar_check_header_crc(ar))
112 warn("Invalid header checksum @%" PRIi64, ar->entry_offset);
113 if (!ar_seek(ar->stream, ar->entry_offset_next, SEEK_SET)) {
114 warn("Couldn't seek to offset %" PRIi64, ar->entry_offset_next);
115 return false;
116 }
117 }
118 }
119
rar_copy_stored(ar_archive_rar * rar,void * buffer,size_t count)120 static bool rar_copy_stored(ar_archive_rar *rar, void *buffer, size_t count)
121 {
122 if (count > rar->progress.data_left) {
123 warn("Unexpected EOS in stored data");
124 return false;
125 }
126 if (ar_read(rar->super.stream, buffer, count) != count) {
127 warn("Unexpected EOF in stored data");
128 return false;
129 }
130 rar->progress.data_left -= count;
131 rar->progress.bytes_done += count;
132 return true;
133 }
134
rar_restart_solid(ar_archive * ar)135 static bool rar_restart_solid(ar_archive *ar)
136 {
137 ar_archive_rar *rar = (ar_archive_rar *)ar;
138 off64_t current_offset = ar->entry_offset;
139 log("Restarting decompression for solid entry");
140 if (!ar_parse_entry_at(ar, ar->entry_offset_first)) {
141 ar_parse_entry_at(ar, current_offset);
142 return false;
143 }
144 while (ar->entry_offset < current_offset) {
145 size_t size = ar->entry_size_uncompressed;
146 rar->solid.restart = false;
147 while (size > 0) {
148 unsigned char buffer[1024];
149 size_t count = smin(size, sizeof(buffer));
150 if (!ar_entry_uncompress(ar, buffer, count)) {
151 ar_parse_entry_at(ar, current_offset);
152 return false;
153 }
154 size -= count;
155 }
156 if (!ar_parse_entry(ar)) {
157 ar_parse_entry_at(ar, current_offset);
158 return false;
159 }
160 }
161 rar->solid.restart = false;
162 return true;
163 }
164
rar_uncompress(ar_archive * ar,void * buffer,size_t count)165 static bool rar_uncompress(ar_archive *ar, void *buffer, size_t count)
166 {
167 ar_archive_rar *rar = (ar_archive_rar *)ar;
168 if (count > ar->entry_size_uncompressed - rar->progress.bytes_done) {
169 warn("Requesting too much data (%" PRIuPTR " < %" PRIuPTR ")", ar->entry_size_uncompressed - rar->progress.bytes_done, count);
170 return false;
171 }
172 if (rar->entry.method == METHOD_STORE) {
173 if (!rar_copy_stored(rar, buffer, count))
174 return false;
175 }
176 else if (rar->entry.method == METHOD_FASTEST || rar->entry.method == METHOD_FAST ||
177 rar->entry.method == METHOD_NORMAL || rar->entry.method == METHOD_GOOD ||
178 rar->entry.method == METHOD_BEST) {
179 if (rar->solid.restart && !rar_restart_solid(ar)) {
180 warn("Failed to produce the required solid decompression state");
181 return false;
182 }
183 if (!rar_uncompress_part(rar, buffer, count))
184 return false;
185 }
186 else {
187 warn("Unknown compression method %#02x", rar->entry.method);
188 return false;
189 }
190
191 rar->progress.crc = ar_crc32(rar->progress.crc, buffer, count);
192 if (rar->progress.bytes_done < ar->entry_size_uncompressed)
193 return true;
194 if (rar->progress.data_left)
195 log("Compressed block has more data than required");
196 rar->solid.part_done = true;
197 rar->solid.size_total += rar->progress.bytes_done;
198 if (rar->progress.crc != rar->entry.crc) {
199 warn("Checksum of extracted data doesn't match");
200 return false;
201 }
202 return true;
203 }
204
ar_open_rar_archive(ar_stream * stream)205 ar_archive *ar_open_rar_archive(ar_stream *stream)
206 {
207 char signature[FILE_SIGNATURE_SIZE];
208 if (!ar_seek(stream, 0, SEEK_SET))
209 return NULL;
210 if (ar_read(stream, signature, sizeof(signature)) != sizeof(signature))
211 return NULL;
212 if (memcmp(signature, "Rar!\x1A\x07\x00", sizeof(signature)) != 0) {
213 if (memcmp(signature, "Rar!\x1A\x07\x01", sizeof(signature)) == 0)
214 warn("RAR 5 format isn't supported");
215 else if (memcmp(signature, "RE~^", 4) == 0)
216 warn("Ancient RAR format isn't supported");
217 else if (memcmp(signature, "MZ", 2) == 0 || memcmp(signature, "\x7F\x45LF", 4) == 0)
218 warn("SFX archives aren't supported");
219 return NULL;
220 }
221
222 return ar_open_archive(stream, sizeof(ar_archive_rar), rar_close, rar_parse_entry, rar_get_name, rar_uncompress, NULL, FILE_SIGNATURE_SIZE);
223 }
224