mirror of
https://github.com/ventoy/Ventoy.git
synced 2024-12-28 08:05:58 -05:00
412 lines
11 KiB
C
412 lines
11 KiB
C
/*
|
|
* Unsquash a squashfs filesystem. This is a highly compressed read only
|
|
* filesystem.
|
|
*
|
|
* Copyright (c) 2009, 2010, 2011, 2012, 2019
|
|
* Phillip Lougher <phillip@squashfs.org.uk>
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version 2,
|
|
* or (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
|
*
|
|
* unsquash-1.c
|
|
*/
|
|
|
|
#include "unsquashfs.h"
|
|
#include "squashfs_compat.h"
|
|
|
|
static unsigned int *uid_table, *guid_table;
|
|
static char *inode_table, *directory_table;
|
|
static squashfs_operations ops;
|
|
|
|
static void read_block_list(unsigned int *block_list, char *block_ptr, int blocks)
|
|
{
|
|
unsigned short block_size;
|
|
int i;
|
|
|
|
TRACE("read_block_list: blocks %d\n", blocks);
|
|
|
|
for(i = 0; i < blocks; i++, block_ptr += 2) {
|
|
if(swap) {
|
|
unsigned short sblock_size;
|
|
memcpy(&sblock_size, block_ptr, sizeof(unsigned short));
|
|
SQUASHFS_SWAP_SHORTS_3((&block_size), &sblock_size, 1);
|
|
} else
|
|
memcpy(&block_size, block_ptr, sizeof(unsigned short));
|
|
block_list[i] = SQUASHFS_COMPRESSED_SIZE(block_size) |
|
|
(SQUASHFS_COMPRESSED(block_size) ? 0 :
|
|
SQUASHFS_COMPRESSED_BIT_BLOCK);
|
|
}
|
|
}
|
|
|
|
|
|
static struct inode *read_inode(unsigned int start_block, unsigned int offset)
|
|
{
|
|
static union squashfs_inode_header_1 header;
|
|
long long start = sBlk.s.inode_table_start + start_block;
|
|
int bytes = lookup_entry(inode_table_hash, start);
|
|
char *block_ptr = inode_table + bytes + offset;
|
|
static struct inode i;
|
|
|
|
TRACE("read_inode: reading inode [%d:%d]\n", start_block, offset);
|
|
|
|
if(bytes == -1)
|
|
EXIT_UNSQUASH("read_inode: inode table block %lld not found\n",
|
|
start);
|
|
|
|
if(swap) {
|
|
squashfs_base_inode_header_1 sinode;
|
|
memcpy(&sinode, block_ptr, sizeof(header.base));
|
|
SQUASHFS_SWAP_BASE_INODE_HEADER_1(&header.base, &sinode,
|
|
sizeof(squashfs_base_inode_header_1));
|
|
} else
|
|
memcpy(&header.base, block_ptr, sizeof(header.base));
|
|
|
|
i.uid = (uid_t) uid_table[(header.base.inode_type - 1) /
|
|
SQUASHFS_TYPES * 16 + header.base.uid];
|
|
if(header.base.inode_type == SQUASHFS_IPC_TYPE) {
|
|
squashfs_ipc_inode_header_1 *inodep = &header.ipc;
|
|
|
|
if(swap) {
|
|
squashfs_ipc_inode_header_1 sinodep;
|
|
memcpy(&sinodep, block_ptr, sizeof(sinodep));
|
|
SQUASHFS_SWAP_IPC_INODE_HEADER_1(inodep, &sinodep);
|
|
} else
|
|
memcpy(inodep, block_ptr, sizeof(*inodep));
|
|
|
|
if(inodep->type == SQUASHFS_SOCKET_TYPE) {
|
|
i.mode = S_IFSOCK | header.base.mode;
|
|
i.type = SQUASHFS_SOCKET_TYPE;
|
|
} else {
|
|
i.mode = S_IFIFO | header.base.mode;
|
|
i.type = SQUASHFS_FIFO_TYPE;
|
|
}
|
|
i.uid = (uid_t) uid_table[inodep->offset * 16 + inodep->uid];
|
|
} else {
|
|
i.mode = lookup_type[(header.base.inode_type - 1) %
|
|
SQUASHFS_TYPES + 1] | header.base.mode;
|
|
i.type = (header.base.inode_type - 1) % SQUASHFS_TYPES + 1;
|
|
}
|
|
|
|
i.xattr = SQUASHFS_INVALID_XATTR;
|
|
i.gid = header.base.guid == 15 ? i.uid :
|
|
(uid_t) guid_table[header.base.guid];
|
|
i.time = sBlk.s.mkfs_time;
|
|
i.inode_number = inode_number ++;
|
|
|
|
switch(i.type) {
|
|
case SQUASHFS_DIR_TYPE: {
|
|
squashfs_dir_inode_header_1 *inode = &header.dir;
|
|
|
|
if(swap) {
|
|
squashfs_dir_inode_header_1 sinode;
|
|
memcpy(&sinode, block_ptr, sizeof(header.dir));
|
|
SQUASHFS_SWAP_DIR_INODE_HEADER_1(inode,
|
|
&sinode);
|
|
} else
|
|
memcpy(inode, block_ptr, sizeof(header.dir));
|
|
|
|
i.data = inode->file_size;
|
|
i.offset = inode->offset;
|
|
i.start = inode->start_block;
|
|
i.time = inode->mtime;
|
|
break;
|
|
}
|
|
case SQUASHFS_FILE_TYPE: {
|
|
squashfs_reg_inode_header_1 *inode = &header.reg;
|
|
|
|
if(swap) {
|
|
squashfs_reg_inode_header_1 sinode;
|
|
memcpy(&sinode, block_ptr, sizeof(sinode));
|
|
SQUASHFS_SWAP_REG_INODE_HEADER_1(inode,
|
|
&sinode);
|
|
} else
|
|
memcpy(inode, block_ptr, sizeof(*inode));
|
|
|
|
i.data = inode->file_size;
|
|
i.time = inode->mtime;
|
|
i.blocks = (i.data + sBlk.s.block_size - 1) >>
|
|
sBlk.s.block_log;
|
|
i.start = inode->start_block;
|
|
i.block_ptr = block_ptr + sizeof(*inode);
|
|
i.fragment = 0;
|
|
i.frag_bytes = 0;
|
|
i.offset = 0;
|
|
i.sparse = 0;
|
|
break;
|
|
}
|
|
case SQUASHFS_SYMLINK_TYPE: {
|
|
squashfs_symlink_inode_header_1 *inodep =
|
|
&header.symlink;
|
|
|
|
if(swap) {
|
|
squashfs_symlink_inode_header_1 sinodep;
|
|
memcpy(&sinodep, block_ptr, sizeof(sinodep));
|
|
SQUASHFS_SWAP_SYMLINK_INODE_HEADER_1(inodep,
|
|
&sinodep);
|
|
} else
|
|
memcpy(inodep, block_ptr, sizeof(*inodep));
|
|
|
|
i.symlink = malloc(inodep->symlink_size + 1);
|
|
if(i.symlink == NULL)
|
|
EXIT_UNSQUASH("read_inode: failed to malloc "
|
|
"symlink data\n");
|
|
strncpy(i.symlink, block_ptr +
|
|
sizeof(squashfs_symlink_inode_header_1),
|
|
inodep->symlink_size);
|
|
i.symlink[inodep->symlink_size] = '\0';
|
|
i.data = inodep->symlink_size;
|
|
break;
|
|
}
|
|
case SQUASHFS_BLKDEV_TYPE:
|
|
case SQUASHFS_CHRDEV_TYPE: {
|
|
squashfs_dev_inode_header_1 *inodep = &header.dev;
|
|
|
|
if(swap) {
|
|
squashfs_dev_inode_header_1 sinodep;
|
|
memcpy(&sinodep, block_ptr, sizeof(sinodep));
|
|
SQUASHFS_SWAP_DEV_INODE_HEADER_1(inodep,
|
|
&sinodep);
|
|
} else
|
|
memcpy(inodep, block_ptr, sizeof(*inodep));
|
|
|
|
i.data = inodep->rdev;
|
|
break;
|
|
}
|
|
case SQUASHFS_FIFO_TYPE:
|
|
case SQUASHFS_SOCKET_TYPE: {
|
|
i.data = 0;
|
|
break;
|
|
}
|
|
default:
|
|
EXIT_UNSQUASH("Unknown inode type %d in "
|
|
" read_inode_header_1!\n",
|
|
header.base.inode_type);
|
|
}
|
|
return &i;
|
|
}
|
|
|
|
|
|
static struct dir *squashfs_opendir(unsigned int block_start, unsigned int offset,
|
|
struct inode **i)
|
|
{
|
|
squashfs_dir_header_2 dirh;
|
|
char buffer[sizeof(squashfs_dir_entry_2) + SQUASHFS_NAME_LEN + 1]
|
|
__attribute__((aligned));
|
|
squashfs_dir_entry_2 *dire = (squashfs_dir_entry_2 *) buffer;
|
|
long long start;
|
|
int bytes;
|
|
int dir_count, size;
|
|
struct dir_ent *new_dir;
|
|
struct dir *dir;
|
|
|
|
TRACE("squashfs_opendir: inode start block %d, offset %d\n",
|
|
block_start, offset);
|
|
|
|
*i = read_inode(block_start, offset);
|
|
|
|
dir = malloc(sizeof(struct dir));
|
|
if(dir == NULL)
|
|
EXIT_UNSQUASH("squashfs_opendir: malloc failed!\n");
|
|
|
|
dir->dir_count = 0;
|
|
dir->cur_entry = 0;
|
|
dir->mode = (*i)->mode;
|
|
dir->uid = (*i)->uid;
|
|
dir->guid = (*i)->gid;
|
|
dir->mtime = (*i)->time;
|
|
dir->xattr = (*i)->xattr;
|
|
dir->dirs = NULL;
|
|
|
|
if ((*i)->data == 0)
|
|
/*
|
|
* if the directory is empty, skip the unnecessary
|
|
* lookup_entry, this fixes the corner case with
|
|
* completely empty filesystems where lookup_entry correctly
|
|
* returning -1 is incorrectly treated as an error
|
|
*/
|
|
return dir;
|
|
|
|
start = sBlk.s.directory_table_start + (*i)->start;
|
|
bytes = lookup_entry(directory_table_hash, start);
|
|
if(bytes == -1)
|
|
EXIT_UNSQUASH("squashfs_opendir: directory block %d not "
|
|
"found!\n", block_start);
|
|
|
|
bytes += (*i)->offset;
|
|
size = (*i)->data + bytes;
|
|
|
|
while(bytes < size) {
|
|
if(swap) {
|
|
squashfs_dir_header_2 sdirh;
|
|
memcpy(&sdirh, directory_table + bytes, sizeof(sdirh));
|
|
SQUASHFS_SWAP_DIR_HEADER_2(&dirh, &sdirh);
|
|
} else
|
|
memcpy(&dirh, directory_table + bytes, sizeof(dirh));
|
|
|
|
dir_count = dirh.count + 1;
|
|
TRACE("squashfs_opendir: Read directory header @ byte position "
|
|
"%d, %d directory entries\n", bytes, dir_count);
|
|
bytes += sizeof(dirh);
|
|
|
|
/* dir_count should never be larger than SQUASHFS_DIR_COUNT */
|
|
if(dir_count > SQUASHFS_DIR_COUNT) {
|
|
ERROR("File system corrupted: too many entries in directory\n");
|
|
goto corrupted;
|
|
}
|
|
|
|
while(dir_count--) {
|
|
if(swap) {
|
|
squashfs_dir_entry_2 sdire;
|
|
memcpy(&sdire, directory_table + bytes,
|
|
sizeof(sdire));
|
|
SQUASHFS_SWAP_DIR_ENTRY_2(dire, &sdire);
|
|
} else
|
|
memcpy(dire, directory_table + bytes,
|
|
sizeof(*dire));
|
|
bytes += sizeof(*dire);
|
|
|
|
/* size should never be SQUASHFS_NAME_LEN or larger */
|
|
if(dire->size >= SQUASHFS_NAME_LEN) {
|
|
ERROR("File system corrupted: filename too long\n");
|
|
goto corrupted;
|
|
}
|
|
|
|
memcpy(dire->name, directory_table + bytes,
|
|
dire->size + 1);
|
|
dire->name[dire->size + 1] = '\0';
|
|
TRACE("squashfs_opendir: directory entry %s, inode "
|
|
"%d:%d, type %d\n", dire->name,
|
|
dirh.start_block, dire->offset, dire->type);
|
|
if((dir->dir_count % DIR_ENT_SIZE) == 0) {
|
|
new_dir = realloc(dir->dirs, (dir->dir_count +
|
|
DIR_ENT_SIZE) * sizeof(struct dir_ent));
|
|
if(new_dir == NULL)
|
|
EXIT_UNSQUASH("squashfs_opendir: "
|
|
"realloc failed!\n");
|
|
dir->dirs = new_dir;
|
|
}
|
|
strcpy(dir->dirs[dir->dir_count].name, dire->name);
|
|
dir->dirs[dir->dir_count].start_block =
|
|
dirh.start_block;
|
|
dir->dirs[dir->dir_count].offset = dire->offset;
|
|
dir->dirs[dir->dir_count].type = dire->type;
|
|
dir->dir_count ++;
|
|
bytes += dire->size + 1;
|
|
}
|
|
}
|
|
|
|
return dir;
|
|
|
|
corrupted:
|
|
free(dir->dirs);
|
|
free(dir);
|
|
return NULL;
|
|
}
|
|
|
|
|
|
squashfs_operations *read_filesystem_tables_1()
|
|
{
|
|
long long table_start;
|
|
|
|
/* Read uid and gid lookup tables */
|
|
|
|
/* Sanity check super block contents */
|
|
if(sBlk.no_guids) {
|
|
if(sBlk.guid_start >= sBlk.s.bytes_used) {
|
|
ERROR("read_filesystem_tables: gid start too large in super block\n");
|
|
goto corrupted;
|
|
}
|
|
|
|
/* In 1.x filesystems, there should never be more than 15 gids */
|
|
if(sBlk.no_guids > 15) {
|
|
ERROR("read_filesystem_tables: gids too large in super block\n");
|
|
goto corrupted;
|
|
}
|
|
|
|
if(read_ids(sBlk.no_guids, sBlk.guid_start, sBlk.s.bytes_used, &guid_table) == FALSE)
|
|
goto corrupted;
|
|
|
|
table_start = sBlk.guid_start;
|
|
} else {
|
|
/* no guids, guid_start should be 0 */
|
|
if(sBlk.guid_start != 0) {
|
|
ERROR("read_filesystem_tables: gid start too large in super block\n");
|
|
goto corrupted;
|
|
}
|
|
|
|
table_start = sBlk.s.bytes_used;
|
|
}
|
|
|
|
if(sBlk.uid_start >= table_start) {
|
|
ERROR("read_filesystem_tables: uid start too large in super block\n");
|
|
goto corrupted;
|
|
}
|
|
|
|
/* There should be at least one uid */
|
|
if(sBlk.no_uids == 0) {
|
|
ERROR("read_filesystem_tables: uid count bad in super block\n");
|
|
goto corrupted;
|
|
}
|
|
|
|
/* In 1.x filesystems, there should never be more than 48 uids */
|
|
if(sBlk.no_uids > 48) {
|
|
ERROR("read_filesystem_tables: uids too large in super block\n");
|
|
goto corrupted;
|
|
}
|
|
|
|
if(read_ids(sBlk.no_uids, sBlk.uid_start, table_start, &uid_table) == FALSE)
|
|
goto corrupted;
|
|
|
|
table_start = sBlk.uid_start;
|
|
|
|
/* Read directory table */
|
|
|
|
/* Sanity check super block contents */
|
|
if(sBlk.s.directory_table_start > table_start) {
|
|
ERROR("read_filesystem_tables: directory table start too large in super block\n");
|
|
goto corrupted;
|
|
}
|
|
|
|
directory_table = read_directory_table(sBlk.s.directory_table_start,
|
|
table_start);
|
|
if(directory_table == NULL)
|
|
goto corrupted;
|
|
|
|
/* Read inode table */
|
|
|
|
/* Sanity check super block contents */
|
|
if(sBlk.s.inode_table_start >= sBlk.s.directory_table_start) {
|
|
ERROR("read_filesystem_tables: inode table start too large in super block\n");
|
|
goto corrupted;
|
|
}
|
|
|
|
inode_table = read_inode_table(sBlk.s.inode_table_start,
|
|
sBlk.s.directory_table_start);
|
|
if(inode_table == NULL)
|
|
goto corrupted;
|
|
|
|
return &ops;
|
|
|
|
corrupted:
|
|
ERROR("File system corruption detected\n");
|
|
return NULL;
|
|
}
|
|
|
|
|
|
static squashfs_operations ops = {
|
|
.opendir = squashfs_opendir,
|
|
.read_block_list = read_block_list,
|
|
.read_inode = read_inode
|
|
};
|