1 /*
2  * Copyright (C) 1996 Wolfgang Solfrank.
3  * Copyright (C) 1996 TooLs GmbH.
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. All advertising materials mentioning features or use of this software
15  *    must display the following acknowledgement:
16  *	This product includes software developed by TooLs GmbH.
17  * 4. The name of TooLs GmbH may not be used to endorse or promote products
18  *    derived from this software without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
26  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
27  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
28  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
29  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 /* Originally derived from libsa/cd9660.c: */
33 /*	$NetBSD: cd9660.c,v 1.5 1997/06/26 19:11:33 drochner Exp $	*/
34 
35 #include <sys/cdefs.h>
36 #include <sys/param.h>
37 
38 #include <fs/cd9660/iso.h>
39 #include <fs/cd9660/cd9660_rrip.h>
40 
41 static uint64_t cd9660_lookup(const char *);
42 static ssize_t cd9660_fsread(uint64_t, void *, size_t);
43 
44 #define	SUSP_CONTINUATION	"CE"
45 #define	SUSP_PRESENT		"SP"
46 #define	SUSP_STOP		"ST"
47 #define	SUSP_EXTREF		"ER"
48 #define	RRIP_NAME		"NM"
49 
50 typedef struct {
51 	ISO_SUSP_HEADER		h;
52 	uint8_t signature	[ISODCL(5,    6)];
53 	uint8_t len_skp		[ISODCL(7,    7)]; /* 711 */
54 } ISO_SUSP_PRESENT;
55 
56 #define	cdb2devb(bno)	((bno) * ISO_DEFAULT_BLOCK_SIZE / DEV_BSIZE)
57 
58 static int
read_iso_block(void * buffer,daddr_t blkno)59 read_iso_block(void *buffer, daddr_t blkno)
60 {
61 
62 	return (drvread(&dsk, buffer, cdb2devb(blkno),
63 	    ISO_DEFAULT_BLOCK_SIZE / DEV_BSIZE));
64 }
65 
66 static ISO_SUSP_HEADER *
susp_lookup_record(const char * identifier,struct iso_directory_record * dp,int lenskip)67 susp_lookup_record(const char *identifier, struct iso_directory_record *dp,
68     int lenskip)
69 {
70 	static char susp_buffer[ISO_DEFAULT_BLOCK_SIZE];
71 	ISO_SUSP_HEADER *sh;
72 	ISO_RRIP_CONT *shc;
73 	char *p, *end;
74 	int error;
75 
76 	p = dp->name + isonum_711(dp->name_len) + lenskip;
77 	/* Names of even length have a padding byte after the name. */
78 	if ((isonum_711(dp->name_len) & 1) == 0)
79 		p++;
80 	end = (char *)dp + isonum_711(dp->length);
81 	while (p + 3 < end) {
82 		sh = (ISO_SUSP_HEADER *)p;
83 		if (bcmp(sh->type, identifier, 2) == 0)
84 			return (sh);
85 		if (bcmp(sh->type, SUSP_STOP, 2) == 0)
86 			return (NULL);
87 		if (bcmp(sh->type, SUSP_CONTINUATION, 2) == 0) {
88 			shc = (ISO_RRIP_CONT *)sh;
89 			error = read_iso_block(susp_buffer,
90 			    isonum_733(shc->location));
91 
92 			/* Bail if it fails. */
93 			if (error != 0)
94 				return (NULL);
95 			p = susp_buffer + isonum_733(shc->offset);
96 			end = p + isonum_733(shc->length);
97 		} else {
98 			/* Ignore this record and skip to the next. */
99 			p += isonum_711(sh->length);
100 
101 			/* Avoid infinite loops with corrupted file systems */
102 			if (isonum_711(sh->length) == 0)
103 				return (NULL);
104 		}
105 	}
106 	return (NULL);
107 }
108 
109 static const char *
rrip_lookup_name(struct iso_directory_record * dp,int lenskip,size_t * len)110 rrip_lookup_name(struct iso_directory_record *dp, int lenskip, size_t *len)
111 {
112 	ISO_RRIP_ALTNAME *p;
113 
114 	if (len == NULL)
115 		return (NULL);
116 
117 	p = (ISO_RRIP_ALTNAME *)susp_lookup_record(RRIP_NAME, dp, lenskip);
118 	if (p == NULL)
119 		return (NULL);
120 	switch (*p->flags) {
121 	case ISO_SUSP_CFLAG_CURRENT:
122 		*len = 1;
123 		return (".");
124 	case ISO_SUSP_CFLAG_PARENT:
125 		*len = 2;
126 		return ("..");
127 	case 0:
128 		*len = isonum_711(p->h.length) - 5;
129 		return ((char *)p + 5);
130 	default:
131 		/*
132 		 * We don't handle hostnames or continued names as they are
133 		 * too hard, so just bail and use the default name.
134 		 */
135 		return (NULL);
136 	}
137 }
138 
139 static int
rrip_check(struct iso_directory_record * dp,int * lenskip)140 rrip_check(struct iso_directory_record *dp, int *lenskip)
141 {
142 	ISO_SUSP_PRESENT *sp;
143 	ISO_RRIP_EXTREF *er;
144 	char *p;
145 
146 	/* First, see if we can find a SP field. */
147 	p = dp->name + isonum_711(dp->name_len);
148 	if (p > (char *)dp + isonum_711(dp->length)) {
149 		return (0);
150 	}
151 	sp = (ISO_SUSP_PRESENT *)p;
152 	if (bcmp(sp->h.type, SUSP_PRESENT, 2) != 0) {
153 		return (0);
154 	}
155 	if (isonum_711(sp->h.length) != sizeof (ISO_SUSP_PRESENT)) {
156 		return (0);
157 	}
158 	if (sp->signature[0] != 0xbe || sp->signature[1] != 0xef) {
159 		return (0);
160 	}
161 	*lenskip = isonum_711(sp->len_skp);
162 
163 	/*
164 	 * Now look for an ER field.  If RRIP is present, then there must
165 	 * be at least one of these.  It would be more pedantic to walk
166 	 * through the list of fields looking for a Rock Ridge ER field.
167 	 */
168 	er = (ISO_RRIP_EXTREF *)susp_lookup_record(SUSP_EXTREF, dp, 0);
169 	if (er == NULL) {
170 		return (0);
171 	}
172 	return (1);
173 }
174 
175 static int
dirmatch(const char * path,struct iso_directory_record * dp,int use_rrip,int lenskip)176 dirmatch(const char *path, struct iso_directory_record *dp, int use_rrip,
177     int lenskip)
178 {
179 	size_t len;
180 	const char *cp = NULL;
181 	int i, icase;
182 
183 	if (use_rrip)
184 		cp = rrip_lookup_name(dp, lenskip, &len);
185 	else
186 		cp = NULL;
187 	if (cp == NULL) {
188 		len = isonum_711(dp->name_len);
189 		cp = dp->name;
190 		icase = 1;
191 	} else
192 		icase = 0;
193 	for (i = len; --i >= 0; path++, cp++) {
194 		if (!*path || *path == '/')
195 			break;
196 		if (*path == *cp)
197 			continue;
198 		if (!icase && toupper(*path) == *cp)
199 			continue;
200 		return (0);
201 	}
202 	if (*path && *path != '/') {
203 		return (0);
204 	}
205 	/*
206 	 * Allow stripping of trailing dots and the version number.
207 	 * Note that this will find the first instead of the last version
208 	 * of a file.
209 	 */
210 	if (i >= 0 && (*cp == ';' || *cp == '.')) {
211 		/* This is to prevent matching of numeric extensions */
212 		if (*cp == '.' && cp[1] != ';') {
213 			return (0);
214 		}
215 		while (--i >= 0)
216 			if (*++cp != ';' && (*cp < '0' || *cp > '9')) {
217 				return (0);
218 			}
219 	}
220 	return (1);
221 }
222 
223 static uint64_t
cd9660_lookup(const char * path)224 cd9660_lookup(const char *path)
225 {
226 	static char blkbuf[MAX(ISO_DEFAULT_BLOCK_SIZE,
227 	    sizeof (struct iso_primary_descriptor))];
228 	struct iso_primary_descriptor *vd;
229 	struct iso_directory_record rec;
230 	struct iso_directory_record *dp = NULL;
231 	size_t dsize, off;
232 	daddr_t bno, boff;
233 	int rc, first, use_rrip, lenskip;
234 	uint64_t cookie;
235 
236 	for (bno = 16; ; bno++) {
237 		rc = read_iso_block(blkbuf, bno);
238 		if (rc != 0)
239 			return (0);
240 		vd = (struct iso_primary_descriptor *)blkbuf;
241 
242 		if (bcmp(vd->id, ISO_STANDARD_ID, sizeof (vd->id)) != 0)
243 			return (0);
244 		if (isonum_711(vd->type) == ISO_VD_END)
245 			return (0);
246 		if (isonum_711(vd->type) == ISO_VD_PRIMARY)
247 			break;
248 	}
249 
250 	bcopy(vd->root_directory_record, &rec, sizeof (rec));
251 	if (*path == '/') path++; /* eat leading '/' */
252 
253 	first = 1;
254 	use_rrip = 0;
255 	lenskip = 0;
256 	while (*path) {
257 		bno = isonum_733(rec.extent) + isonum_711(rec.ext_attr_length);
258 		dsize = isonum_733(rec.size);
259 		off = 0;
260 		boff = 0;
261 
262 		while (off < dsize) {
263 			if ((off % ISO_DEFAULT_BLOCK_SIZE) == 0) {
264 				rc = read_iso_block(blkbuf, bno + boff);
265 				if (rc) {
266 					return (0);
267 				}
268 				boff++;
269 				dp = (struct iso_directory_record *)blkbuf;
270 			}
271 			if (isonum_711(dp->length) == 0) {
272 				/* skip to next block, if any */
273 				off = boff * ISO_DEFAULT_BLOCK_SIZE;
274 				continue;
275 			}
276 
277 			/* See if RRIP is in use. */
278 			if (first)
279 				use_rrip = rrip_check(dp, &lenskip);
280 
281 			if (dirmatch(path, dp, use_rrip,
282 			    first ? 0 : lenskip)) {
283 				first = 0;
284 				break;
285 			} else
286 				first = 0;
287 
288 			dp = (struct iso_directory_record *)
289 			    ((char *)dp + isonum_711(dp->length));
290 			/* If the new block has zero length, it is padding. */
291 			if (isonum_711(dp->length) == 0) {
292 				/* Skip to next block, if any. */
293 				off = boff * ISO_DEFAULT_BLOCK_SIZE;
294 				continue;
295 			}
296 			off += isonum_711(dp->length);
297 		}
298 		if (off >= dsize) {
299 			return (0);
300 		}
301 
302 		rec = *dp;
303 		while (*path && *path != '/') /* look for next component */
304 			path++;
305 		if (*path) path++; /* skip '/' */
306 	}
307 
308 	if ((isonum_711(rec.flags) & 2) != 0) {
309 		return (0);
310 	}
311 
312 	cookie = isonum_733(rec.extent) + isonum_711(rec.ext_attr_length);
313 	cookie = (cookie << 32) | isonum_733(rec.size);
314 
315 	return (cookie);
316 }
317 
318 static ssize_t
cd9660_fsread(uint64_t cookie,void * buf,size_t nbytes)319 cd9660_fsread(uint64_t cookie, void *buf, size_t nbytes)
320 {
321 	static char blkbuf[ISO_DEFAULT_BLOCK_SIZE];
322 	static daddr_t curstart = 0, curblk = 0;
323 	daddr_t blk, blk_off;
324 	off_t byte_off;
325 	size_t size, remaining, n;
326 	char *s;
327 
328 	size = cookie & 0xffffffff;
329 	blk = (cookie >> 32) & 0xffffffff;
330 
331 	/* Make sure we're looking at the right file. */
332 	if ((uint64_t)((blk << 32) | size) != cookie) {
333 		return (-1);
334 	}
335 
336 	if (blk != curstart) {
337 		curstart = blk;
338 		fs_off = 0;
339 	}
340 
341 	size -= fs_off;
342 	if (size < nbytes) {
343 		nbytes = size;
344 	}
345 	remaining = nbytes;
346 	s = buf;
347 
348 	while (remaining > 0) {
349 		blk_off = fs_off >> ISO_DEFAULT_BLOCK_SHIFT;
350 		byte_off = fs_off & (ISO_DEFAULT_BLOCK_SIZE - 1);
351 
352 		if (curblk != curstart + blk_off) {
353 			curblk = curstart + blk_off;
354 			read_iso_block(blkbuf, curblk);
355 		}
356 
357 		if (remaining < ISO_DEFAULT_BLOCK_SIZE - byte_off) {
358 			n = remaining;
359 		} else {
360 			n = ISO_DEFAULT_BLOCK_SIZE - byte_off;
361 		}
362 		memcpy(s, blkbuf + byte_off, n);
363 		remaining -= n;
364 		s += n;
365 
366 		fs_off += n;
367 	}
368 
369 	return (nbytes);
370 }
371