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libisofs/libisofs/rockridge_read.c

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/*
* Copyright (c) 2007 Vreixo Formoso
* Copyright (c) 2009 Thomas Schmitt
*
* This file is part of the libisofs project; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2
* or later as published by the Free Software Foundation.
* See COPYING file for details.
*/
/*
* This file contains functions related to the reading of SUSP,
* Rock Ridge and AAIP extensions on an ECMA-119 image.
*/
#ifdef HAVE_CONFIG_H
#include "../config.h"
#endif
#include "libisofs.h"
#include "ecma119.h"
#include "util.h"
#include "rockridge.h"
#include "messages.h"
#include <sys/stat.h>
#include <stdlib.h>
#include <string.h>
struct susp_iterator
{
uint8_t* base;
int pos;
int size;
IsoDataSource *src;
int msgid;
/* Number of blocks in the ISO 9660 filesystem */
uint32_t fs_blocks;
/* block and offset for next continuation area */
uint32_t ce_block;
uint32_t ce_off;
/** Length of the next continuation area, 0 if no more CA are specified */
uint32_t ce_len;
uint8_t *buffer; /*< If there are continuation areas */
};
SuspIterator*
susp_iter_new(IsoDataSource *src, struct ecma119_dir_record *record,
uint32_t fs_blocks, uint8_t len_skp, int msgid)
{
int pad = (record->len_fi[0] + 1) % 2;
struct susp_iterator *iter = malloc(sizeof(struct susp_iterator));
if (iter == NULL) {
return NULL;
}
iter->base = record->file_id + record->len_fi[0] + pad;
iter->pos = len_skp; /* 0 in most cases */
iter->size = record->len_dr[0] - record->len_fi[0] - 33 - pad;
iter->src = src;
iter->msgid = msgid;
iter->fs_blocks = fs_blocks;
iter->ce_len = 0;
iter->buffer = NULL;
return iter;
}
/* More than 1 MiB in a single file's CE area is suspicious */
#define ISO_SUSP_MAX_CE_BYTES (1024 * 1024)
/* @param flag bit0 = First call on root:
Not yet clear whether this is SUSP at all
*/
int susp_iter_next(SuspIterator *iter, struct susp_sys_user_entry **sue,
int flag)
{
struct susp_sys_user_entry *entry;
entry = (struct susp_sys_user_entry*)(iter->base + iter->pos);
if (flag & 1) {
/* Yet unclear whether it is SUSP at all */
if (iter->size < 7)
return 0;
if (!SUSP_SIG(entry, 'S', 'P'))
return 0;
if (entry->len_sue[0] < 7)
return 0;
/* Looks like SUSP enough to pass the further processing here. */
}
if ( (iter->pos + 4 > iter->size) || (SUSP_SIG(entry, 'S', 'T'))) {
/*
* End of the System Use Area or Continuation Area.
* Note that ST is not needed when the space left is less than 4.
* (IEEE 1281, SUSP. section 4)
*/
if (iter->ce_len) {
uint32_t block, nblocks, skipped_blocks, skipped_bytes;
/* A CE was found, there is another continuation area */
skipped_blocks = iter->ce_off / BLOCK_SIZE;
skipped_bytes = skipped_blocks * BLOCK_SIZE;
nblocks = DIV_UP(iter->ce_off - skipped_bytes + iter->ce_len,
BLOCK_SIZE);
if (nblocks <= 0 || iter->ce_len > ISO_SUSP_MAX_CE_BYTES)
return ISO_SUSP_WRONG_CE_SIZE;
if (((uint64_t) iter->ce_block) + skipped_blocks + nblocks >
(uint64_t) iter->fs_blocks)
return ISO_SUSP_WRONG_CE_SIZE;
iter->buffer = realloc(iter->buffer, nblocks * BLOCK_SIZE);
/* Read blocks needed to cache the given CE area range */
for (block = 0; block < nblocks; ++block) {
int ret;
ret = iter->src->read_block(iter->src,
iter->ce_block + skipped_blocks + block,
iter->buffer + block * BLOCK_SIZE);
if (ret < 0) {
return ret;
}
}
iter->base = iter->buffer + (iter->ce_off - skipped_bytes);
iter->pos = 0;
iter->size = iter->ce_len;
iter->ce_len = 0;
entry = (struct susp_sys_user_entry*)iter->base;
} else {
return 0;
}
}
if (entry->len_sue[0] == 0) {
/* a wrong image with this lead us to a infinity loop */
iso_msg_submit(iter->msgid, ISO_WRONG_RR, 0,
"Damaged RR/SUSP information.");
return ISO_WRONG_RR;
}
iter->pos += entry->len_sue[0];
if (SUSP_SIG(entry, 'C', 'E')) {
/* Continuation entry */
if (iter->ce_len) {
int ret;
ret = iso_msg_submit(iter->msgid, ISO_UNSUPPORTED_SUSP, 0,
"More than one CE System user entry has found in a single "
"System Use field or continuation area. This breaks SUSP "
"standard and it's not supported. Ignoring last CE. Maybe "
"the image is damaged.");
if (ret < 0) {
return ret;
}
} else {
iter->ce_block = iso_read_bb(entry->data.CE.block, 4, NULL);
iter->ce_off = iso_read_bb(entry->data.CE.offset, 4, NULL);
iter->ce_len = iso_read_bb(entry->data.CE.len, 4, NULL);
}
/* we don't want to return CE entry to the user */
return susp_iter_next(iter, sue, 0);
} else if (SUSP_SIG(entry, 'P', 'D')) {
/* skip padding */
return susp_iter_next(iter, sue, 0);
}
*sue = entry;
return ISO_SUCCESS;
}
void susp_iter_free(SuspIterator *iter)
{
free(iter->buffer);
free(iter);
}
/**
* Fills a struct stat with the values of a Rock Ridge PX entry (RRIP, 4.1.1).
*
* @return
* 1 on success, < 0 on error
*/
int read_rr_PX(struct susp_sys_user_entry *px, struct stat *st)
{
if (px == NULL || st == NULL) {
return ISO_NULL_POINTER;
}
if (px->sig[0] != 'P' || px->sig[1] != 'X') {
return ISO_WRONG_ARG_VALUE;
}
if (px->len_sue[0] != 44 && px->len_sue[0] != 36) {
return ISO_WRONG_RR;
}
st->st_mode = iso_read_bb(px->data.PX.mode, 4, NULL);
st->st_nlink = iso_read_bb(px->data.PX.links, 4, NULL);
st->st_uid = iso_read_bb(px->data.PX.uid, 4, NULL);
st->st_gid = iso_read_bb(px->data.PX.gid, 4, NULL);
st->st_ino = 0;
if (px->len_sue[0] == 44) {
/* this corresponds to RRIP 1.12, so we have inode serial number */
st->st_ino = iso_read_bb(px->data.PX.serial, 4, NULL);
/* Indicate that st_ino is valid */
return 2;
}
return 1;
}
/**
* Fills a struct stat with the values of a Rock Ridge TF entry (RRIP, 4.1.6)
*
* @return
* 1 on success, < 0 on error
*/
int read_rr_TF(struct susp_sys_user_entry *tf, struct stat *st)
{
time_t time;
int s;
int nts = 0;
if (tf == NULL || st == NULL) {
return ISO_NULL_POINTER;
}
if (tf->sig[0] != 'T' || tf->sig[1] != 'F') {
return ISO_WRONG_ARG_VALUE;
}
if (tf->data.TF.flags[0] & (1 << 7)) {
/* long form */
s = 17;
} else {
s = 7;
}
/* 1. Creation time */
if (tf->data.TF.flags[0] & (1 << 0)) {
/* Linux accepts ctime by Creation time and by Attributes time.
* If both are given, then Attribute time will win.
*/
if (tf->len_sue[0] < 5 + (nts+1) * s) {
/* RR TF entry too short. */
return ISO_WRONG_RR;
}
if (s == 7) {
time = iso_datetime_read_7(&tf->data.TF.t_stamps[nts*7]);
} else {
time = iso_datetime_read_17(&tf->data.TF.t_stamps[nts*17]);
}
st->st_ctime = time;
++nts;
}
/* 2. modify time */
if (tf->data.TF.flags[0] & (1 << 1)) {
if (tf->len_sue[0] < 5 + (nts+1) * s) {
/* RR TF entry too short. */
return ISO_WRONG_RR;
}
if (s == 7) {
time = iso_datetime_read_7(&tf->data.TF.t_stamps[nts*7]);
} else {
time = iso_datetime_read_17(&tf->data.TF.t_stamps[nts*17]);
}
st->st_mtime = time;
++nts;
}
/* 3. access time */
if (tf->data.TF.flags[0] & (1 << 2)) {
if (tf->len_sue[0] < 5 + (nts+1) * s) {
/* RR TF entry too short. */
return ISO_WRONG_RR;
}
if (s == 7) {
time = iso_datetime_read_7(&tf->data.TF.t_stamps[nts*7]);
} else {
time = iso_datetime_read_17(&tf->data.TF.t_stamps[nts*17]);
}
st->st_atime = time;
++nts;
}
/* 4. attributes time */
if (tf->data.TF.flags[0] & (1 << 3)) {
if (tf->len_sue[0] < 5 + (nts+1) * s) {
/* RR TF entry too short. */
return ISO_WRONG_RR;
}
if (s == 7) {
time = iso_datetime_read_7(&tf->data.TF.t_stamps[nts*7]);
} else {
time = iso_datetime_read_17(&tf->data.TF.t_stamps[nts*17]);
}
st->st_ctime = time;
++nts;
}
/* we ignore backup, expire and effect times */
return ISO_SUCCESS;
}
/**
* Read a RR NM entry (RRIP, 4.1.4), and appends the name stored there to
* the given name. You can pass a pointer to NULL as name.
*
* @return
* 1 on success, < 0 on error
*/
int read_rr_NM(struct susp_sys_user_entry *nm, char **name, int *cont)
{
if (nm == NULL || name == NULL) {
return ISO_NULL_POINTER;
}
if (nm->sig[0] != 'N' || nm->sig[1] != 'M') {
return ISO_WRONG_ARG_VALUE;
}
if (nm->len_sue[0] == 5) {
if (nm->data.NM.flags[0] & 0x2) {
/* it is a "." entry */
if (*name == NULL) {
return ISO_SUCCESS;
} else {
/* we can't have a previous not-NULL name */
return ISO_WRONG_RR;
}
}
}
if (nm->len_sue[0] <= 5) {
/* ".." entry is an error, as we will never call it */
return ISO_WRONG_RR;
}
/* concatenate the results */
if (*cont) {
*name = realloc(*name, strlen(*name) + nm->len_sue[0] - 5 + 1);
strncat(*name, (char*)nm->data.NM.name, nm->len_sue[0] - 5);
} else {
*name = iso_util_strcopy((char*)nm->data.NM.name, nm->len_sue[0] - 5);
}
if (*name == NULL) {
return ISO_OUT_OF_MEM;
}
/* and set cond according to the value of CONTINUE flag */
*cont = nm->data.NM.flags[0] & 0x01;
return ISO_SUCCESS;
}
/**
* Read a SL RR entry (RRIP, 4.1.3), checking if the destination continues.
*
* @param cont
* 0 not continue, 1 continue, 2 continue component
* @return
* 1 on success, < 0 on error
*/
int read_rr_SL(struct susp_sys_user_entry *sl, char **dest, int *cont)
{
int pos;
if (sl == NULL || dest == NULL) {
return ISO_NULL_POINTER;
}
if (sl->sig[0] != 'S' || sl->sig[1] != 'L') {
return ISO_WRONG_ARG_VALUE;
}
for (pos = 0; pos + 5 < sl->len_sue[0];
pos += 2 + sl->data.SL.comps[pos + 1]) {
char *comp;
uint8_t len;
uint8_t flags = sl->data.SL.comps[pos];
if (flags & 0x2) {
/* current directory */
len = 1;
comp = ".";
} else if (flags & 0x4) {
/* parent directory */
len = 2;
comp = "..";
} else if (flags & 0x8) {
/* root directory */
len = 1;
comp = "/";
} else if (flags & ~0x01) {
/* unsupported flag component */
return ISO_UNSUPPORTED_RR;
} else {
len = sl->data.SL.comps[pos + 1];
comp = (char*)&sl->data.SL.comps[pos + 2];
}
if (*cont == 1) {
/* new component */
size_t size = strlen(*dest);
int has_slash;
*dest = realloc(*dest, strlen(*dest) + len + 2);
if (*dest == NULL) {
return ISO_OUT_OF_MEM;
}
/* it is a new compoenent, add the '/' */
has_slash = 0;
if (size > 0)
if ((*dest)[size - 1] == '/')
has_slash = 1;
if (!has_slash) {
(*dest)[size] = '/';
(*dest)[size+1] = '\0';
}
strncat(*dest, comp, len);
} else if (*cont == 2) {
/* the component continues */
*dest = realloc(*dest, strlen(*dest) + len + 1);
if (*dest == NULL) {
return ISO_OUT_OF_MEM;
}
/* we don't have to add the '/' */
strncat(*dest, comp, len);
} else {
*dest = iso_util_strcopy(comp, len);
}
if (*dest == NULL) {
return ISO_OUT_OF_MEM;
}
/* do the component continue or not? */
*cont = (flags & 0x01) ? 2 : 1;
}
if (*cont == 2) {
/* TODO check that SL flag is set to continute too ?*/
} else {
*cont = sl->data.SL.flags[0] & 0x1 ? 1 : 0;
}
return ISO_SUCCESS;
}
/**
* Fills a struct stat with the values of a Rock Ridge PN entry (RRIP, 4.1.2).
*
* @return
* 1 on success, < 0 on error
*/
int read_rr_PN(struct susp_sys_user_entry *pn, struct stat *st)
{
int high_shift= 0;
if (pn == NULL || st == NULL) {
return ISO_NULL_POINTER;
}
if (pn->sig[0] != 'P' || pn->sig[1] != 'N') {
return ISO_WRONG_ARG_VALUE;
}
if (pn->len_sue[0] != 20) {
return ISO_WRONG_RR;
}
/* (dev_t << 32) causes compiler warnings on FreeBSD
because sizeof(dev_t) is 4.
*/
st->st_rdev = (dev_t)iso_read_bb(pn->data.PN.low, 4, NULL);
if (sizeof(st->st_rdev) > 4) {
high_shift = 32;
st->st_rdev |= (dev_t)((dev_t)iso_read_bb(pn->data.PN.high, 4, NULL) <<
high_shift);
}
/* was originally:
st->st_rdev = (dev_t)((dev_t)iso_read_bb(pn->data.PN.high, 4, NULL) << 32)
| (dev_t)iso_read_bb(pn->data.PN.low, 4, NULL);
*/
return ISO_SUCCESS;
}
/* AA is the obsolete field signature of AAIP versions < 2.0
*/
int read_aaip_AA(struct susp_sys_user_entry *sue,
unsigned char **aa_string, size_t *aa_size, size_t *aa_len,
size_t *prev_field, int *is_done, int flag)
{
unsigned char *aapt;
if (*is_done) {
/* To coexist with Apple ISO :
Gracefully react on possibly trailing Apple AA
*/
if (sue->version[0] != 1 || sue->len_sue[0] == 7)
return ISO_SUCCESS;
return ISO_WRONG_RR;
}
if (*aa_size == 0 || *aa_string == NULL) {
/* Gracefully react on possibly leading Apple AA
*/
if (sue->version[0] != 1 || sue->len_sue[0] < 9)
return ISO_SUCCESS;
}
/* A valid AAIP AA entry has 5 header bytes and at least 1 component byte
*/
if (sue->len_sue[0] < 6)
return ISO_WRONG_RR;
/* Possibly create or grow storage */
if (*aa_size == 0 || *aa_string == NULL) {
*aa_size = *aa_len + sue->len_sue[0];
*aa_string = calloc(*aa_size, 1);
*aa_len = 0;
} else if (*aa_len + sue->len_sue[0] > *aa_size) {
if (sue->version[0] != 1) {
/* Apple ISO within the AAIP field group is not AAIP compliant
*/
return ISO_WRONG_RR;
}
*aa_size += *aa_len + sue->len_sue[0];
*aa_string = realloc(*aa_string, *aa_size);
}
if (*aa_string == NULL)
return ISO_OUT_OF_MEM;
if (*aa_len > 0) {
/* Mark prev_field as being continued */
(*aa_string)[*prev_field + 4] = 1;
}
*prev_field = *aa_len;
/* Compose new SUSP header with signature aa[], cont == 0 */
aapt = *aa_string + *aa_len;
aapt[0] = 'A';
aapt[1] = 'L';
aapt[2] = sue->len_sue[0];
aapt[3] = 1;
aapt[4] = 0;
/* Append sue payload */
memcpy(aapt + 5, sue->data.AL.comps, sue->len_sue[0] - 5);
*is_done = !(sue->data.AL.flags[0] & 1);
*aa_len += sue->len_sue[0];
return ISO_SUCCESS;
}
/* AL is the field signature of AAIP versions >= 2.0
*/
int read_aaip_AL(struct susp_sys_user_entry *sue,
unsigned char **aa_string, size_t *aa_size, size_t *aa_len,
size_t *prev_field, int *is_done, int flag)
{
unsigned char *aapt;
if (*is_done)
return ISO_WRONG_RR;
if (sue->version[0] != 1)
return ISO_WRONG_RR;
/* A valid AL entry has 5 header bytes and at least 1 component byte
*/
if (sue->len_sue[0] < 6)
return ISO_WRONG_RR;
/* Possibly create or grow storage */
if (*aa_size == 0 || *aa_string == NULL) {
*aa_size = *aa_len + sue->len_sue[0];
*aa_string = calloc(*aa_size, 1);
*aa_len = 0;
} else if (*aa_len + sue->len_sue[0] > *aa_size) {
*aa_size += *aa_len + sue->len_sue[0];
*aa_string = realloc(*aa_string, *aa_size);
}
if (*aa_string == NULL)
return ISO_OUT_OF_MEM;
if (*aa_len > 0) {
/* Mark prev_field as being continued */
(*aa_string)[*prev_field + 4] = 1;
}
*prev_field = *aa_len;
/* Compose new SUSP header with signature aa[], cont == 0 */
aapt = *aa_string + *aa_len;
aapt[0] = 'A';
aapt[1] = 'L';
aapt[2] = sue->len_sue[0];
aapt[3] = 1;
aapt[4] = 0;
/* Append sue payload */
memcpy(aapt + 5, sue->data.AL.comps, sue->len_sue[0] - 5);
*is_done = !(sue->data.AL.flags[0] & 1);
*aa_len += sue->len_sue[0];
return ISO_SUCCESS;
}
/**
* Reads the zisofs parameters from a ZF field (see doc/zisofs_format.txt).
*
* @return
* 1 on success, < 0 on error
*/
int read_zisofs_ZF(struct susp_sys_user_entry *zf, uint8_t algorithm[2],
uint8_t *header_size_div4, uint8_t *block_size_log2,
uint32_t *uncompressed_size, int flag)
{
if (zf == NULL) {
return ISO_NULL_POINTER;
}
if (zf->sig[0] != 'Z' || zf->sig[1] != 'F') {
return ISO_WRONG_ARG_VALUE;
}
if (zf->len_sue[0] != 16) {
return ISO_WRONG_RR;
}
algorithm[0] = zf->data.ZF.parameters[0];
algorithm[1] = zf->data.ZF.parameters[1];
*header_size_div4 = zf->data.ZF.parameters[2];
*block_size_log2 = zf->data.ZF.parameters[3];
*uncompressed_size = iso_read_bb(&(zf->data.ZF.parameters[4]), 4, NULL);
return ISO_SUCCESS;
}
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