void Filter::unfilter(upx_byte *buf_, unsigned buf_len_, bool verify_checksum)
{
initFilter(this, buf_, buf_len_);
const FilterImp::FilterEntry * const fe = FilterImp::getFilter(id);
if (fe == NULL)
throwInternalError("unfilter-1");
if (fe->id == 0)
return;
if (buf_len < fe->min_buf_len)
return;
if (fe->max_buf_len && buf_len > fe->max_buf_len)
return;
if (!fe->do_unfilter)
throwInternalError("unfilter-2");
//printf("unfilter: %02x %p %d\n", this->id, this->buf, this->buf_len);
int r = (*fe->do_unfilter)(this);
//printf("unfilter: %02x %d\n", fe->id, r);
if (r != 0)
throwInternalError("unfilter-3");
//OutputFile::dump("unfilter.dat", buf, buf_len);
// verify checksum
if (verify_checksum && clevel != 1)
{
if (this->adler != upx_adler32(this->buf, this->buf_len))
throwInternalError("unfilter-4");
}
}
bool Filter::filter(upx_byte *buf_, unsigned buf_len_)
{
initFilter(this, buf_, buf_len_);
const FilterImp::FilterEntry * const fe = FilterImp::getFilter(id);
if (fe == NULL)
throwInternalError("filter-1");
if (fe->id == 0)
return true;
if (buf_len < fe->min_buf_len)
return false;
if (fe->max_buf_len && buf_len > fe->max_buf_len)
return false;
if (!fe->do_filter)
throwInternalError("filter-2");
// save checksum
this->adler = 0;
if (clevel != 1)
this->adler = upx_adler32(this->buf, this->buf_len);
//printf("filter: %02x %p %d\n", this->id, this->buf, this->buf_len);
//OutputFile::dump("filter.dat", buf, buf_len);
int r = (*fe->do_filter)(this);
//printf("filter: %02x %d\n", fe->id, r);
if (r > 0)
throwFilterException();
if (r == 0)
return true;
return false;
}
void
PackUnix::patchLoaderChecksum()
{
unsigned char *const ptr = getLoader();
l_info *const lp = &linfo;
// checksum for loader; also some PackHeader info
lp->l_magic = UPX_MAGIC_LE32; // LE32 always
set_te16(&lp->l_lsize, (upx_uint16_t) lsize);
lp->l_version = (unsigned char) ph.version;
lp->l_format = (unsigned char) ph.format;
// INFO: lp->l_checksum is currently unused
set_te32(&lp->l_checksum, upx_adler32(ptr, lsize));
}
void PackLinuxElf32x86interp::unpack(OutputFile *fo)
{
#define MAX_INTERP_HDR 512
union {
unsigned char buf[MAX_INTERP_HDR];
//struct { Elf32_Ehdr ehdr; Elf32_Phdr phdr; } e;
} u;
Elf32_Ehdr *const ehdr = (Elf32_Ehdr *) u.buf;
Elf32_Phdr const *phdr = (Elf32_Phdr *) (u.buf + sizeof(*ehdr));
unsigned szb_info = sizeof(b_info);
{
fi->seek(0, SEEK_SET);
fi->readx(u.buf, MAX_INTERP_HDR);
unsigned const e_entry = get_te32(&ehdr->e_entry);
if (e_entry < 0x401180) { /* old style, 8-byte b_info */
szb_info = 2*sizeof(unsigned);
}
}
fi->seek(overlay_offset, SEEK_SET);
p_info hbuf;
fi->readx(&hbuf, sizeof(hbuf));
unsigned orig_file_size = get_te32(&hbuf.p_filesize);
blocksize = get_te32(&hbuf.p_blocksize);
if (file_size > (off_t)orig_file_size || blocksize > orig_file_size)
throwCantUnpack("file header corrupted");
ibuf.alloc(blocksize + OVERHEAD);
b_info bhdr; memset(&bhdr, 0, sizeof(bhdr));
fi->readx(&bhdr, szb_info);
ph.u_len = get_te32(&bhdr.sz_unc);
ph.c_len = get_te32(&bhdr.sz_cpr);
ph.filter_cto = bhdr.b_cto8;
// Uncompress Ehdr and Phdrs.
fi->readx(ibuf, ph.c_len);
decompress(ibuf, (upx_byte *)ehdr, false);
unsigned total_in = 0;
unsigned total_out = 0;
unsigned c_adler = upx_adler32(NULL, 0);
unsigned u_adler = upx_adler32(NULL, 0);
off_t ptload0hi=0, ptload1lo=0, ptload1sz=0;
// decompress PT_LOAD
bool first_PF_X = true;
fi->seek(- (off_t) (szb_info + ph.c_len), SEEK_CUR);
for (unsigned j=0; j < ehdr->e_phnum; ++phdr, ++j) {
if (PT_LOAD==phdr->p_type) {
if (0==ptload0hi) {
ptload0hi = phdr->p_filesz + phdr->p_offset;
}
else if (0==ptload1lo) {
ptload1lo = phdr->p_offset;
ptload1sz = phdr->p_filesz;
}
if (fo)
fo->seek(phdr->p_offset, SEEK_SET);
if (Elf32_Phdr::PF_X & phdr->p_flags) {
unpackExtent(phdr->p_filesz, fo, total_in, total_out,
c_adler, u_adler, first_PF_X, szb_info);
first_PF_X = false;
}
else {
unpackExtent(phdr->p_filesz, fo, total_in, total_out,
c_adler, u_adler, false, szb_info);
}
}
}
if (0!=ptload1sz && ptload0hi < ptload1lo) { // alignment hole?
if (fo)
fo->seek(ptload0hi, SEEK_SET);
unpackExtent(ptload1lo - ptload0hi, fo, total_in, total_out,
c_adler, u_adler, false, szb_info);
}
if (total_out != orig_file_size) { // non-PT_LOAD stuff
if (fo)
fo->seek(0, SEEK_END);
unpackExtent(orig_file_size - total_out, fo, total_in, total_out,
c_adler, u_adler, false, szb_info);
}
// check for end-of-file
fi->readx(&bhdr, szb_info);
unsigned const sz_unc = ph.u_len = get_te32(&bhdr.sz_unc);
if (sz_unc == 0) { // uncompressed size 0 -> EOF
// note: magic is always stored le32
unsigned const sz_cpr = get_le32(&bhdr.sz_cpr);
if (sz_cpr != UPX_MAGIC_LE32) // sz_cpr must be h->magic
throwCompressedDataViolation();
}
else { // extra bytes after end?
throwCompressedDataViolation();
}
// update header with totals
ph.c_len = total_in;
ph.u_len = total_out;
// all bytes must be written
if (total_out != orig_file_size)
throwEOFException();
// finally test the checksums
if (ph.c_adler != c_adler || ph.u_adler != u_adler)
throwChecksumError();
#undef MAX_INTERP_HDR
}
void PackUnix::unpack(OutputFile *fo)
{
unsigned const szb_info = sizeof(b_info);
unsigned c_adler = upx_adler32(NULL, 0);
unsigned u_adler = upx_adler32(NULL, 0);
// defaults for ph.version == 8
unsigned orig_file_size = 0;
blocksize = 512 * 1024;
fi->seek(overlay_offset, SEEK_SET);
if (ph.version > 8)
{
p_info hbuf;
fi->readx(&hbuf, sizeof(hbuf));
orig_file_size = get_te32(&hbuf.p_filesize);
blocksize = get_te32(&hbuf.p_blocksize);
if (file_size > (off_t)orig_file_size || blocksize > orig_file_size)
throwCantUnpack("file header corrupted");
}
else
{
// skip 4 bytes (program id)
fi->seek(4, SEEK_CUR);
}
if ((int)(blocksize + OVERHEAD) < 0)
throwCantUnpack("blocksize corrupted");
ibuf.alloc(blocksize + OVERHEAD);
// decompress blocks
unsigned total_in = 0;
unsigned total_out = 0;
b_info bhdr; memset(&bhdr, 0, sizeof(bhdr));
for (;;)
{
#define buf ibuf
int i;
unsigned sz_unc, sz_cpr;
fi->readx(&bhdr, szb_info);
ph.u_len = sz_unc = get_te32(&bhdr.sz_unc);
ph.c_len = sz_cpr = get_te32(&bhdr.sz_cpr);
if (sz_unc == 0) // uncompressed size 0 -> EOF
{
// note: must reload sz_cpr as magic is always stored le32
sz_cpr = get_le32(&bhdr.sz_cpr);
if (sz_cpr != UPX_MAGIC_LE32) // sz_cpr must be h->magic
throwCompressedDataViolation();
break;
}
if (sz_unc <= 0 || sz_cpr <= 0)
throwCompressedDataViolation();
if (sz_cpr > sz_unc || sz_unc > blocksize)
throwCompressedDataViolation();
i = blocksize + OVERHEAD - sz_cpr;
if (i < 0)
throwCantUnpack("corrupt b_info");
fi->readx(buf+i, sz_cpr);
// update checksum of compressed data
c_adler = upx_adler32(buf + i, sz_cpr, c_adler);
// decompress
if (sz_cpr < sz_unc) {
decompress(buf+i, buf, false);
if (0!=bhdr.b_ftid) {
Filter ft(ph.level);
ft.init(bhdr.b_ftid);
ft.cto = bhdr.b_cto8;
ft.unfilter(buf, sz_unc);
}
i = 0;
}
// update checksum of uncompressed data
u_adler = upx_adler32(buf + i, sz_unc, u_adler);
total_in += sz_cpr;
total_out += sz_unc;
// write block
if (fo)
fo->write(buf + i, sz_unc);
#undef buf
}
// update header with totals
ph.c_len = total_in;
ph.u_len = total_out;
// all bytes must be written
if (ph.version > 8 && total_out != orig_file_size)
throwEOFException();
// finally test the checksums
if (ph.c_adler != c_adler || ph.u_adler != u_adler)
throwChecksumError();
}
void PackUnix::unpackExtent(unsigned wanted, OutputFile *fo,
unsigned &total_in, unsigned &total_out,
unsigned &c_adler, unsigned &u_adler,
bool first_PF_X, unsigned szb_info
)
{
b_info hdr; memset(&hdr, 0, sizeof(hdr));
while (wanted) {
fi->readx(&hdr, szb_info);
int const sz_unc = ph.u_len = get_te32(&hdr.sz_unc);
int const sz_cpr = ph.c_len = get_te32(&hdr.sz_cpr);
ph.filter_cto = hdr.b_cto8;
if (sz_unc == 0) { // must never happen while 0!=wanted
throwCantUnpack("corrupt b_info");
break;
}
if (sz_unc <= 0 || sz_cpr <= 0)
throwCantUnpack("corrupt b_info");
if (sz_cpr > sz_unc || sz_unc > (int)blocksize)
throwCantUnpack("corrupt b_info");
int j = blocksize + OVERHEAD - sz_cpr;
fi->readx(ibuf+j, sz_cpr);
// update checksum of compressed data
c_adler = upx_adler32(ibuf + j, sz_cpr, c_adler);
// decompress
if (sz_cpr < sz_unc)
{
decompress(ibuf+j, ibuf, false);
if (12==szb_info) { // modern per-block filter
if (hdr.b_ftid) {
Filter ft(ph.level); // FIXME: ph.level for b_info?
ft.init(hdr.b_ftid, 0);
ft.cto = hdr.b_cto8;
ft.unfilter(ibuf, sz_unc);
}
}
else { // ancient per-file filter
if (first_PF_X) { // Elf32_Ehdr is never filtered
first_PF_X = false; // but everything else might be
}
else if (ph.filter) {
Filter ft(ph.level);
ft.init(ph.filter, 0);
ft.cto = (unsigned char) ph.filter_cto;
ft.unfilter(ibuf, sz_unc);
}
}
j = 0;
}
// update checksum of uncompressed data
u_adler = upx_adler32(ibuf + j, sz_unc, u_adler);
total_in += sz_cpr;
total_out += sz_unc;
// write block
if (fo)
fo->write(ibuf + j, sz_unc);
if (wanted < (unsigned)sz_unc)
throwCantUnpack("corrupt b_info");
wanted -= sz_unc;
}
}
void PackUnix::packExtent(
const Extent &x,
unsigned &total_in,
unsigned &total_out,
Filter *ft,
OutputFile *fo,
unsigned hdr_u_len
)
{
unsigned const init_u_adler = ph.u_adler;
unsigned const init_c_adler = ph.c_adler;
MemBuffer hdr_ibuf;
if (hdr_u_len) {
hdr_ibuf.alloc(hdr_u_len);
fi->seek(0, SEEK_SET);
int l = fi->readx(hdr_ibuf, hdr_u_len);
(void)l;
}
fi->seek(x.offset, SEEK_SET);
for (off_t rest = x.size; 0 != rest; ) {
int const filter_strategy = ft ? getStrategy(*ft) : 0;
int l = fi->readx(ibuf, UPX_MIN(rest, (off_t)blocksize));
if (l == 0) {
break;
}
rest -= l;
// Note: compression for a block can fail if the
// file is e.g. blocksize + 1 bytes long
// compress
ph.c_len = ph.u_len = l;
ph.overlap_overhead = 0;
unsigned end_u_adler = 0;
if (ft) {
// compressWithFilters() updates u_adler _inside_ compress();
// that is, AFTER filtering. We want BEFORE filtering,
// so that decompression checks the end-to-end checksum.
end_u_adler = upx_adler32(ibuf, ph.u_len, ph.u_adler);
ft->buf_len = l;
// compressWithFilters() requirements?
ph.filter = 0;
ph.filter_cto = 0;
ft->id = 0;
ft->cto = 0;
compressWithFilters(ft, OVERHEAD, NULL_cconf, filter_strategy,
0, 0, 0, hdr_ibuf, hdr_u_len);
}
else {
(void) compress(ibuf, ph.u_len, obuf); // ignore return value
}
if (ph.c_len < ph.u_len) {
const upx_bytep tbuf = NULL;
if (ft == NULL || ft->id == 0) tbuf = ibuf;
ph.overlap_overhead = OVERHEAD;
if (!testOverlappingDecompression(obuf, tbuf, ph.overlap_overhead)) {
// not in-place compressible
ph.c_len = ph.u_len;
}
}
if (ph.c_len >= ph.u_len) {
// block is not compressible
ph.c_len = ph.u_len;
memcpy(obuf, ibuf, ph.c_len);
// must update checksum of compressed data
ph.c_adler = upx_adler32(ibuf, ph.u_len, ph.saved_c_adler);
}
// write block sizes
b_info tmp;
if (hdr_u_len) {
unsigned hdr_c_len = 0;
MemBuffer hdr_obuf;
hdr_obuf.allocForCompression(hdr_u_len);
int r = upx_compress(hdr_ibuf, hdr_u_len, hdr_obuf, &hdr_c_len, 0,
ph.method, 10, NULL, NULL);
if (r != UPX_E_OK)
throwInternalError("header compression failed");
if (hdr_c_len >= hdr_u_len)
throwInternalError("header compression size increase");
ph.saved_u_adler = upx_adler32(hdr_ibuf, hdr_u_len, init_u_adler);
ph.saved_c_adler = upx_adler32(hdr_obuf, hdr_c_len, init_c_adler);
ph.u_adler = upx_adler32(ibuf, ph.u_len, ph.saved_u_adler);
ph.c_adler = upx_adler32(obuf, ph.c_len, ph.saved_c_adler);
end_u_adler = ph.u_adler;
memset(&tmp, 0, sizeof(tmp));
set_te32(&tmp.sz_unc, hdr_u_len);
set_te32(&tmp.sz_cpr, hdr_c_len);
tmp.b_method = (unsigned char) ph.method;
fo->write(&tmp, sizeof(tmp));
b_len += sizeof(b_info);
fo->write(hdr_obuf, hdr_c_len);
total_out += hdr_c_len;
total_in += hdr_u_len;
hdr_u_len = 0; // compress hdr one time only
}
memset(&tmp, 0, sizeof(tmp));
set_te32(&tmp.sz_unc, ph.u_len);
set_te32(&tmp.sz_cpr, ph.c_len);
if (ph.c_len < ph.u_len) {
tmp.b_method = (unsigned char) ph.method;
if (ft) {
tmp.b_ftid = (unsigned char) ft->id;
tmp.b_cto8 = ft->cto;
}
}
fo->write(&tmp, sizeof(tmp));
b_len += sizeof(b_info);
if (ft) {
ph.u_adler = end_u_adler;
}
// write compressed data
if (ph.c_len < ph.u_len) {
fo->write(obuf, ph.c_len);
// Checks ph.u_adler after decompression, after unfiltering
verifyOverlappingDecompression(ft);
}
else {
fo->write(ibuf, ph.u_len);
}
total_in += ph.u_len;
total_out += ph.c_len;
}
}
int PackUnix::pack2(OutputFile *fo, Filter &ft)
{
// compress blocks
unsigned total_in = 0;
unsigned total_out = 0;
// FIXME: ui_total_passes is not correct with multiple blocks...
// ui_total_passes = (file_size + blocksize - 1) / blocksize;
// if (ui_total_passes == 1)
// ui_total_passes = 0;
unsigned remaining = file_size;
unsigned n_block = 0;
while (remaining > 0)
{
// FIXME: disable filters if we have more than one block.
// FIXME: There is only 1 un-filter in the stub [as of 2002-11-10].
// So the next block really has no choice!
// This merely prevents an assert() in compressWithFilters(),
// which assumes it has free choice on each call [block].
// And if the choices aren't the same on each block,
// then un-filtering will give incorrect results.
int filter_strategy = getStrategy(ft);
if (file_size > (off_t)blocksize)
filter_strategy = -3; // no filters
int l = fi->readx(ibuf, UPX_MIN(blocksize, remaining));
remaining -= l;
// Note: compression for a block can fail if the
// file is e.g. blocksize + 1 bytes long
// compress
ph.overlap_overhead = 0;
ph.c_len = ph.u_len = l;
ft.buf_len = l;
// compressWithFilters() updates u_adler _inside_ compress();
// that is, AFTER filtering. We want BEFORE filtering,
// so that decompression checks the end-to-end checksum.
unsigned const end_u_adler = upx_adler32(ibuf, ph.u_len, ph.u_adler);
compressWithFilters(&ft, OVERHEAD, NULL_cconf, filter_strategy,
!!n_block++); // check compression ratio only on first block
if (ph.c_len < ph.u_len) {
const upx_bytep tbuf = NULL;
if (ft.id == 0) tbuf = ibuf;
ph.overlap_overhead = OVERHEAD;
if (!testOverlappingDecompression(obuf, tbuf, ph.overlap_overhead)) {
// not in-place compressible
ph.c_len = ph.u_len;
}
}
if (ph.c_len >= ph.u_len) {
// block is not compressible
ph.c_len = ph.u_len;
// must manually update checksum of compressed data
ph.c_adler = upx_adler32(ibuf, ph.u_len, ph.saved_c_adler);
}
// write block header
b_info blk_info;
memset(&blk_info, 0, sizeof(blk_info));
set_te32(&blk_info.sz_unc, ph.u_len);
set_te32(&blk_info.sz_cpr, ph.c_len);
if (ph.c_len < ph.u_len) {
blk_info.b_method = (unsigned char) ph.method;
blk_info.b_ftid = (unsigned char) ph.filter;
blk_info.b_cto8 = (unsigned char) ph.filter_cto;
}
fo->write(&blk_info, sizeof(blk_info));
b_len += sizeof(b_info);
// write compressed data
if (ph.c_len < ph.u_len) {
fo->write(obuf, ph.c_len);
verifyOverlappingDecompression(); // uses ph.u_adler
}
else {
fo->write(ibuf, ph.u_len);
}
ph.u_adler = end_u_adler;
total_in += ph.u_len;
total_out += ph.c_len;
}
// update header with totals
ph.u_len = total_in;
ph.c_len = total_out;
if ((off_t)total_in != file_size) {
throwEOFException();
}
return 1; // default: write end-of-compression bhdr next
}
