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upx/src/p_vmlinx.cpp
Markus F.X.J. Oberhumer c4da5e81fa Welcome 2017.
2017-01-03 12:02:07 +01:00

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/* p_vmlinx.cpp -- pack vmlinux ET_EXEC file (before bootsect or setup)
This file is part of the UPX executable compressor.
Copyright (C) 2004-2017 John Reiser
Copyright (C) 1996-2017 Markus Franz Xaver Johannes Oberhumer
Copyright (C) 1996-2017 Laszlo Molnar
All Rights Reserved.
UPX and the UCL library are free software; you can redistribute them
and/or modify them under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, 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; see the file COPYING.
If not, write to the Free Software Foundation, Inc.,
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
Markus F.X.J. Oberhumer Laszlo Molnar
<markus@oberhumer.com> <ezerotven+github@gmail.com>
John Reiser
<jreiser@users.sourceforge.net>
*/
#include "conf.h"
#include "file.h"
#include "filter.h"
#include "packer.h"
#include "p_vmlinx.h"
#include "linker.h"
static const
#include "stub/i386-linux.kernel.vmlinux.h"
static const
#include "stub/amd64-linux.kernel.vmlinux.h"
static const
#include "stub/arm.v5a-linux.kernel.vmlinux.h"
static const
#include "stub/armeb.v5a-linux.kernel.vmlinux.h"
static const
#include "stub/powerpc-linux.kernel.vmlinux.h"
/*************************************************************************
//
**************************************************************************/
template <class T>
PackVmlinuxBase<T>::PackVmlinuxBase(InputFile *f,
unsigned e_machine, unsigned elfclass, unsigned elfdata,
char const *const boot_label) :
super(f),
my_e_machine(e_machine), my_elfclass(elfclass), my_elfdata(elfdata),
my_boot_label(boot_label),
n_ptload(0), phdri(NULL), shdri(NULL), shstrtab(NULL)
{
ElfClass::compileTimeAssertions();
bele = N_BELE_CTP::getRTP((const BeLePolicy*) NULL);
}
template <class T>
PackVmlinuxBase<T>::~PackVmlinuxBase()
{
delete [] phdri;
delete [] shdri;
delete [] shstrtab;
}
template <class T>
int PackVmlinuxBase<T>::getStrategy(Filter &/*ft*/)
{
// Called just before reading and compressing each block.
// Might want to adjust blocksize, etc.
// If user specified the filter, then use it (-2==strategy).
// Else try the first two filters, and pick the better (2==strategy).
return (opt->no_filter ? -3 : ((opt->filter > 0) ? -2 : 2));
}
template <class T>
int __acc_cdecl_qsort
PackVmlinuxBase<T>::compare_Phdr(void const *aa, void const *bb)
{
Phdr const *const a = (Phdr const *)aa;
Phdr const *const b = (Phdr const *)bb;
unsigned const xa = a->p_type - Phdr::PT_LOAD;
unsigned const xb = b->p_type - Phdr::PT_LOAD;
if (xa < xb) return -1; // PT_LOAD first
if (xa > xb) return 1;
if (a->p_paddr < b->p_paddr) return -1; // ascending by .p_paddr
if (a->p_paddr > b->p_paddr) return 1;
return 0;
}
template <class T>
typename T::Shdr const *PackVmlinuxBase<T>::getElfSections()
{
Shdr const *p, *shstrsec=0;
shdri = new Shdr[(unsigned) ehdri.e_shnum];
fi->seek(ehdri.e_shoff, SEEK_SET);
fi->readx(shdri, ehdri.e_shnum * sizeof(*shdri));
int j;
for (p = shdri, j= ehdri.e_shnum; --j>=0; ++p) {
if (Shdr::SHT_STRTAB==p->sh_type
&& (p->sh_size + p->sh_offset) <= (unsigned) file_size
&& (10+ p->sh_name) <= p->sh_size // 1+ strlen(".shstrtab")
) {
delete [] shstrtab;
shstrtab = new char[1+ p->sh_size];
fi->seek(p->sh_offset, SEEK_SET);
fi->readx(shstrtab, p->sh_size);
shstrtab[p->sh_size] = '\0';
if (0==strcmp(".shstrtab", shstrtab + p->sh_name)) {
shstrsec = p;
break;
}
}
}
return shstrsec;
}
template <class T>
bool PackVmlinuxBase<T>::canPack()
{
fi->seek(0, SEEK_SET);
fi->readx(&ehdri, sizeof(ehdri));
// now check the ELF header
if (memcmp(&ehdri, "\x7f\x45\x4c\x46", 4)
|| ehdri.e_ident[Ehdr::EI_CLASS] != my_elfclass
|| ehdri.e_ident[Ehdr::EI_DATA] != my_elfdata
|| ehdri.e_ident[Ehdr::EI_VERSION] != Ehdr::EV_CURRENT
|| !memcmp(&ehdri.e_ident[8], "FreeBSD", 7) // branded
|| ehdri.e_machine != my_e_machine
|| ehdri.e_version != 1 // version
|| ehdri.e_ehsize != sizeof(ehdri) // different <elf.h> ?
) {
return false;
}
// additional requirements for vmlinux
if (ehdri.e_type != Ehdr::ET_EXEC
|| ehdri.e_phoff != sizeof(ehdri) // Phdr not contiguous with Ehdr
|| ehdri.e_phentsize!=sizeof(Phdr)
|| !is_valid_e_entry(ehdri.e_entry)
) {
return false;
}
// A Linux kernel must have a __ksymtab section. [??]
Shdr const *p, *const shstrsec = getElfSections();
if (0==shstrsec) {
return false;
}
{
int j;
for (p = shdri, j= ehdri.e_shnum; --j>=0; ++p) {
if (Shdr::SHT_PROGBITS==p->sh_type
&& (p->sh_name + shstrsec->sh_offset) < (unsigned)file_size
&& 0==strcmp("__ksymtab", p->sh_name + shstrtab)) {
break;
}
}
if (j < 0) {
return false;
}
}
phdri = new Phdr[(unsigned) ehdri.e_phnum];
fi->seek(ehdri.e_phoff, SEEK_SET);
fi->readx(phdri, ehdri.e_phnum * sizeof(*phdri));
// Put PT_LOAD together at the beginning, ascending by .p_paddr.
qsort(phdri, ehdri.e_phnum, sizeof(*phdri), compare_Phdr);
// Find convex hull of physical addresses, and count the PT_LOAD.
// Ignore ".bss": .p_filesz < .p_memsz
unsigned phys_lo= ~0u, phys_hi= 0u;
for (unsigned j = 0; j < ehdri.e_phnum; ++j) {
if (Phdr::PT_LOAD==phdri[j].p_type) {
// Check for general sanity (not necessarily required.)
if (0xfff & (phdri[j].p_offset | phdri[j].p_paddr
| phdri[j].p_align | phdri[j].p_vaddr) ) {
return false;
}
if (phys_lo > phdri[j].p_paddr) {
phys_lo = phdri[j].p_paddr;
}
if (phys_hi < (phdri[j].p_filesz + phdri[j].p_paddr)) {
phys_hi = (phdri[j].p_filesz + phdri[j].p_paddr);
}
++n_ptload;
}
}
paddr_min = phys_lo;
sz_ptload = phys_hi - phys_lo;
return 0 < n_ptload;
}
#include "p_elf.h"
template <class T>
void PackVmlinuxBase<T>::pack(OutputFile *fo)
{
unsigned fo_off = 0;
Ehdr ehdro;
TE32 tmp_u32;
// NULL
// .text(PT_LOADs) .note(1st page) .note(rest)
// .shstrtab .symtab .strtab
Shdr shdro[1+3+3];
memset(shdro, 0, sizeof(shdro));
ibuf.alloc(file_size);
obuf.allocForCompression(file_size);
// .e_ident, .e_machine, .e_version, .e_flags
memcpy(&ehdro, &ehdri, sizeof(ehdro));
ehdro.e_type = Ehdr::ET_REL;
ehdro.e_entry = 0;
ehdro.e_phoff = 0;
ehdro.e_shoff = sizeof(ehdro);
ehdro.e_phentsize = 0;
ehdro.e_phnum = 0;
ehdro.e_shnum = 1+3+3;
ehdro.e_shstrndx = 4;
fo->write(&ehdro, sizeof(ehdro)); fo_off+= sizeof(ehdro);
fo->write(shdro, sizeof(shdro)); fo_off+= sizeof(shdro);
// Notice overlap [containment] of physical PT_LOAD[2] into PTLOAD[1]
// in this vmlinux for x86_64 from Fedora Core 6 on 2007-01-07:
//Program Headers:
// Type Offset VirtAddr PhysAddr
// FileSiz MemSiz Flags Align
// LOAD 0x0000000000200000 0xffffffff80200000 0x0000000000200000
// 0x000000000034bce8 0x000000000034bce8 R E 200000
// LOAD 0x000000000054c000 0xffffffff8054c000 0x000000000054c000
// 0x00000000000ed004 0x00000000001702a4 RWE 200000
// LOAD 0x0000000000800000 0xffffffffff600000 0x00000000005f5000
// 0x0000000000000c08 0x0000000000000c08 RWE 200000
// NOTE 0x0000000000000000 0x0000000000000000 0x0000000000000000
// 0x0000000000000000 0x0000000000000000 R 8
// Therefore we must "compose" the convex hull to be loaded.
ph.u_len = sz_ptload;
memset(ibuf, 0, sz_ptload);
for (unsigned j = 0; j < ehdri.e_phnum; ++j) {
if (Phdr::PT_LOAD==phdri[j].p_type) {
fi->seek(phdri[j].p_offset, SEEK_SET);
fi->readx(ibuf + ((unsigned) phdri[j].p_paddr - paddr_min), phdri[j].p_filesz);
}
}
checkAlreadyPacked(ibuf + ph.u_len - 1024, 1024);
// prepare filter
ph.filter = 0;
Filter ft(ph.level);
ft.buf_len = ph.u_len;
ft.addvalue = 0; // we are independent of actual runtime address; see ckt32
upx_compress_config_t cconf; cconf.reset();
// limit stack size needed for runtime decompression
cconf.conf_lzma.max_num_probs = 1846 + (768 << 4); // ushort: ~28 KiB stack
unsigned ppc32_extra = 0;
if (Ehdr::EM_PPC==my_e_machine) {
// output layout:
// .long UPX_MAGIC_LE32
// .long L20 - L10
// L10:
// b_info for Ehdr; compressed Ehdr; .balign 4 // one block only
// b_info for LOAD; compressed LOAD; .balign 4 // possibly many blocks
// // This allows per-block filters!
// L20:
// b f_decompress
// +4: f_unfilter(char *buf, unsigned len, unsigned cto8, unsigned ftid)
// // Code for multiple filters can "daisy chain" on ftid.
// f_decompress(char const *src, unsigned src_len,
// char *dst, unsigned *dst_len, int method)
unsigned tmp;
tmp = UPX_MAGIC_LE32; fo->write(&tmp, sizeof(tmp)); fo_off += sizeof(tmp);
tmp = 0; fo->write(&tmp, sizeof(tmp)); fo_off += sizeof(tmp);
ppc32_extra += 2*sizeof(tmp);
unsigned const len_unc = sizeof(ehdri) + sizeof(Phdr) * ehdri.e_phnum;
MemBuffer unc_hdr(len_unc);
MemBuffer cpr_hdr; cpr_hdr.allocForCompression(len_unc);
memcpy(&unc_hdr[0], &ehdri, sizeof(ehdri));
memcpy(&unc_hdr[sizeof(ehdri)], phdri, sizeof(Phdr) * ehdri.e_phnum);
unsigned len_cpr = 0;
int const r = upx_compress(unc_hdr, len_unc, cpr_hdr, &len_cpr,
NULL, ph.method, 10, NULL, NULL );
if (UPX_E_OK!=r || len_unc<=len_cpr) // FIXME: allow no compression
throwInternalError("Ehdr compression failed");
__packed_struct(b_info) // 12-byte header before each compressed block
unsigned sz_unc; // uncompressed_size
unsigned sz_cpr; // compressed_size
unsigned char b_method; // compression algorithm
unsigned char b_ftid; // filter id
unsigned char b_cto8; // filter parameter
unsigned char b_unused; // FIXME: !=0 for partial-block unfilter
// unsigned f_offset, f_len; // only if partial-block unfilter
__packed_struct_end()
struct b_info hdr_info;
set_be32(&hdr_info.sz_unc, len_unc);
set_be32(&hdr_info.sz_cpr, len_cpr);
hdr_info.b_method = ph.method;
hdr_info.b_ftid = 0;
hdr_info.b_cto8 = 0;
hdr_info.b_unused = 0;
fo->write(&hdr_info, sizeof(hdr_info)); fo_off += sizeof(hdr_info);
unsigned const frag = (3& (0u-len_cpr));
ppc32_extra += sizeof(hdr_info) + len_cpr + frag;
fo_off += len_cpr + frag;
memset(&cpr_hdr[len_cpr], 0, frag); // valgrind only
fo->write(cpr_hdr, len_cpr + frag);
// Partial filter: .text and following contiguous SHF_EXECINSTR
upx_bytep f_ptr = ibuf;
unsigned f_len = 0;
Shdr const *shdr = 1+ shdri; // skip empty shdr[0]
if (ft.buf_len==0 // not specified yet FIXME: was set near construction
&& (Shdr::SHF_ALLOC & shdr->sh_flags)
&& (Shdr::SHF_EXECINSTR & shdr->sh_flags)) {
// shdr[1] is instructions (probably .text)
f_ptr = ibuf + (unsigned) (shdr->sh_offset - phdri[0].p_offset);
f_len = shdr->sh_size;
++shdr;
for (int j= ehdri.e_shnum - 2; --j>=0; ++shdr) {
unsigned prev_end = shdr[-1].sh_size + shdr[-1].sh_offset;
prev_end += ~(0u-shdr[0].sh_addralign) & (0u-prev_end); // align_up
if ((Shdr::SHF_ALLOC & shdr->sh_flags)
&& (Shdr::SHF_EXECINSTR & shdr->sh_flags)
&& shdr[0].sh_offset==prev_end) {
f_len += shdr->sh_size;
}
else {
break;
}
}
}
else { // ft.buf_len already specified, or Shdr[1] not instructions
f_ptr = ibuf;
f_len = ph.u_len;
}
compressWithFilters(ibuf, ph.u_len, obuf,
f_ptr, f_len, // filter range
NULL, 0, // hdr_ptr, hdr_len
&ft, 512, &cconf, getStrategy(ft));
set_be32(&hdr_info.sz_unc, ph.u_len);
set_be32(&hdr_info.sz_cpr, ph.c_len);
hdr_info.b_ftid = ft.id;
hdr_info.b_cto8 = ft.cto;
if (ph.u_len!=f_len) {
hdr_info.b_unused = 1; // flag for partial filter
}
fo->write(&hdr_info, sizeof(hdr_info)); fo_off += sizeof(hdr_info);
ppc32_extra += sizeof(hdr_info);
if (ph.u_len!=f_len) {
set_be32(&hdr_info.sz_unc, f_ptr - (upx_bytep) ibuf);
set_be32(&hdr_info.sz_cpr, f_len);
fo->write(&hdr_info, 2*sizeof(unsigned)); fo_off += 2*sizeof(unsigned);
ppc32_extra += 2*sizeof(unsigned);
}
}
else {
compressWithFilters(&ft, 512, &cconf, getStrategy(ft));
}
unsigned const txt_c_len = ph.c_len;
const unsigned lsize = getLoaderSize();
defineDecompressorSymbols();
defineFilterSymbols(&ft);
relocateLoader();
MemBuffer loader(lsize);
memcpy(loader, getLoader(), lsize);
patchPackHeader(loader, lsize);
#define shstrtab local_shstrtab // avoid -Wshadow warning
char const shstrtab[]= "\0.text\0.note\0.shstrtab\0.symtab\0.strtab";
char const *p = shstrtab;
while (0!=*p++) ;
shdro[1].sh_name = ptr_diff(p, shstrtab);
shdro[1].sh_type = Shdr::SHT_PROGBITS;
shdro[1].sh_flags = Shdr::SHF_ALLOC | Shdr::SHF_EXECINSTR;
shdro[1].sh_offset = fo_off - ppc32_extra;
shdro[1].sh_size = ppc32_extra + txt_c_len + lsize; // plus more ...
shdro[1].sh_addralign = 1; // default
fo_off += write_vmlinux_head(fo, &shdro[1]);
fo->write(obuf, txt_c_len); fo_off += txt_c_len;
unsigned const a = (shdro[1].sh_addralign -1) & (0u-(ppc32_extra + txt_c_len));
if (0!=a) { // align
fo_off += a;
shdro[1].sh_size += a;
fo->seek(a, SEEK_CUR);
}
fo->write(loader, lsize); fo_off += lsize;
#if 0
printf("%-13s: compressed : %8u bytes\n", getName(), txt_c_len);
printf("%-13s: decompressor : %8u bytes\n", getName(), lsize);
#endif
verifyOverlappingDecompression();
// .note with 1st page --------------------------------
ph.u_len = phdri[0].p_offset;
fi->seek(0, SEEK_SET);
fi->readx(ibuf, ph.u_len);
compress(ibuf, ph.u_len, obuf, &cconf);
while (0!=*p++) ;
shdro[2].sh_name = ptr_diff(p, shstrtab);
shdro[2].sh_type = Shdr::SHT_NOTE;
shdro[2].sh_offset = fo_off;
shdro[2].sh_size = sizeof(ph.u_len) + ph.c_len;
shdro[2].sh_addralign = 1;
tmp_u32 = ph.u_len; fo->write(&tmp_u32, 4);
fo->write(obuf, ph.c_len); fo_off += shdro[2].sh_size;
// .note with rest --------------------------------
ph.u_len = file_size - (sz_ptload + phdri[0].p_offset);
fi->seek(sz_ptload + phdri[0].p_offset, SEEK_SET);
fi->readx(ibuf, ph.u_len);
// Temporarily decrease ph.level by about (1+ log2(sz_rest / sz_ptload))
// to avoid spending unreasonable effort compressing large symbol tables
// that are discarded 99.9% of the time anyway.
int const old_level = ph.level;
for (unsigned v = ((ph.u_len>>3) + ph.u_len) / sz_ptload; 0 < v; v>>=1) {
if (0== --ph.level) {
ph.level = 1;
}
}
compress(ibuf, ph.u_len, obuf, &cconf);
ph.level = old_level;
// while (0!=*p++) ; // name is the same
shdro[3].sh_name = ptr_diff(p, shstrtab);
shdro[3].sh_type = Shdr::SHT_NOTE;
shdro[3].sh_offset = fo_off;
shdro[3].sh_size = sizeof(ph.u_len) + ph.c_len;
shdro[3].sh_addralign = 1;
tmp_u32 = ph.u_len; fo->write(&tmp_u32, 4);
fo->write(obuf, ph.c_len); fo_off += shdro[3].sh_size;
while (0!=*p++) ;
shdro[4].sh_name = ptr_diff(p, shstrtab);
shdro[4].sh_type = Shdr::SHT_STRTAB;
shdro[4].sh_offset = fo_off;
shdro[4].sh_size = sizeof(shstrtab); // already includes terminating '\0'
shdro[4].sh_addralign = 1;
fo->write(shstrtab, shdro[4].sh_size); fo_off += shdro[4].sh_size;
fo_off = ~3 & (3+ fo_off); fo->seek(fo_off, SEEK_SET);
while (0!=*p++) ;
shdro[5].sh_name = ptr_diff(p, shstrtab);
shdro[5].sh_type = Shdr::SHT_SYMTAB;
shdro[5].sh_offset = fo_off;
shdro[5].sh_size = ((Ehdr::EM_PPC==my_e_machine) + 5)*sizeof(Sym);
//shdro[5].sh_flags = Shdr::SHF_INFO_LINK;
shdro[5].sh_link = 6; // to .strtab for symbols
shdro[5].sh_info = 1+3; // number of non-global symbols [binutils/bfd/elf.c]
shdro[5].sh_addralign = 4;
shdro[5].sh_entsize = sizeof(Sym);
Sym sec_sym;
// Symbol 0; no references, but bfd demands it.
memset(&sec_sym, 0, sizeof(sec_sym));
fo->write(&sec_sym, sizeof(sec_sym)); fo_off += sizeof(sec_sym);
// Each section before .shstrtab needs a symbol.
sec_sym.st_info = sec_sym.make_st_info(Sym::STB_LOCAL, Sym::STT_SECTION);
sec_sym.st_other = Sym::STV_DEFAULT;
sec_sym.st_shndx = 1; // .text
fo->write(&sec_sym, sizeof(sec_sym)); fo_off += sizeof(sec_sym);
sec_sym.st_shndx = 2; // .note
fo->write(&sec_sym, sizeof(sec_sym)); fo_off += sizeof(sec_sym);
sec_sym.st_shndx = 3; // .note
fo->write(&sec_sym, sizeof(sec_sym)); fo_off += sizeof(sec_sym);
// the symbol we care about
Sym unc_ker;
unc_ker.st_name = 1; // 1 byte into strtab
unc_ker.st_value = 0;
unc_ker.st_size = ppc32_extra + txt_c_len;
unc_ker.st_info = unc_ker.make_st_info(Sym::STB_GLOBAL, Sym::STT_FUNC);
unc_ker.st_other = Sym::STV_DEFAULT;
unc_ker.st_shndx = 1; // .text
fo->write(&unc_ker, sizeof(unc_ker)); fo_off += sizeof(unc_ker);
unsigned const lablen = strlen(my_boot_label);
if (Ehdr::EM_PPC==my_e_machine) {
unc_ker.st_name += 1+ lablen;
unc_ker.st_value = unc_ker.st_size;
unc_ker.st_size = 0;
fo->write(&unc_ker, sizeof(unc_ker)); fo_off += sizeof(unc_ker);
}
while (0!=*p++) ;
shdro[6].sh_name = ptr_diff(p, shstrtab);
shdro[6].sh_type = Shdr::SHT_STRTAB;
shdro[6].sh_offset = fo_off;
shdro[6].sh_size = 2+ lablen + (Ehdr::EM_PPC==my_e_machine)*(1+ 12); // '\0' before and after
shdro[6].sh_addralign = 1;
fo->seek(1, SEEK_CUR); // the '\0' before
fo->write(my_boot_label, 1+ lablen); // include the '\0' terminator
if (Ehdr::EM_PPC==my_e_machine) {
fo->write("_vmlinux_end", 1+ 12); fo_off += 1+ 12;
}
fo_off += 2+ lablen;
fo->seek(0, SEEK_SET);
fo->write(&ehdro, sizeof(ehdro));
fo->write(&shdro[0], sizeof(shdro));
if (Ehdr::EM_PPC==my_e_machine) {
fo->seek(sizeof(unsigned), SEEK_CUR);
set_be32(&ppc32_extra, ppc32_extra - 2*sizeof(unsigned) + txt_c_len);
fo->write(&ppc32_extra, sizeof(ppc32_extra));
}
if (!checkFinalCompressionRatio(fo))
throwNotCompressible();
#undef shstrtab
}
template <class T>
int PackVmlinuxBase<T>::canUnpack()
{
fi->seek(0, SEEK_SET);
fi->readx(&ehdri, sizeof(ehdri));
// now check the ELF header
if (memcmp(&ehdri, "\x7f\x45\x4c\x46", 4)
|| ehdri.e_ident[Ehdr::EI_CLASS] != my_elfclass
|| ehdri.e_ident[Ehdr::EI_DATA] != my_elfdata
|| ehdri.e_ident[Ehdr::EI_VERSION] != Ehdr::EV_CURRENT
|| !memcmp(&ehdri.e_ident[8], "FreeBSD", 7) // branded
|| ehdri.e_machine != my_e_machine
|| ehdri.e_version != 1 // version
|| ehdri.e_ehsize != sizeof(ehdri) // different <elf.h> ?
)
return false;
if (ehdri.e_type != Ehdr::ET_REL
//i386 fails || ehdri.e_shoff != sizeof(ehdri) // Shdr not contiguous with Ehdr
|| ehdri.e_shentsize!=sizeof(Shdr)
|| ehdri.e_shnum < 4
|| (unsigned)file_size < (ehdri.e_shnum * sizeof(Shdr) + ehdri.e_shoff)
)
return false;
// find the .shstrtab section
Shdr const *const shstrsec = getElfSections();
if (0==shstrsec) {
return false;
}
// check for .text .note .note and sane (.sh_size + .sh_offset)
p_note0 = p_note1 = p_text = 0;
int j;
Shdr *p;
for (p= shdri, j= ehdri.e_shnum; --j>=0; ++p) {
if ((unsigned)file_size < (p->sh_size + p->sh_offset)
|| shstrsec->sh_size < (5+ p->sh_name) ) {
continue;
}
if (0==strcmp(".text", shstrtab + p->sh_name)) {
p_text = p;
}
if (0==strcmp(".note", shstrtab + p->sh_name)) {
if (0==p_note0) {
p_note0 = p;
} else
if (0==p_note1) {
p_note1 = p;
}
}
}
if (0==p_text || 0==p_note0 || 0==p_note1) {
return false;
}
char buf[1024];
fi->seek(p_text->sh_offset + p_text->sh_size - sizeof(buf), SEEK_SET);
fi->readx(buf, sizeof(buf));
if (!getPackHeader(buf, sizeof(buf)))
return -1; // format is known, but definitely is not packed
return true;
}
template <class T>
void PackVmlinuxBase<T>::unpack(OutputFile *fo)
{
TE32 word;
PackHeader const ph_tmp(ph);
fi->seek(p_note0->sh_offset, SEEK_SET);
fi->readx(&word, sizeof(word));
ph.u_len = word;
ph.c_len = p_note0->sh_size - sizeof(word);
ibuf.alloc(ph.c_len);
fi->readx(ibuf, ph.c_len);
obuf.allocForUncompression(ph.u_len);
decompress(ibuf, obuf, false);
fo->write(obuf, ph.u_len);
obuf.dealloc();
ibuf.dealloc();
ph = ph_tmp;
if (!has_valid_vmlinux_head()) {
throwCantUnpack(".text corrupted");
}
ibuf.alloc(ph.c_len);
fi->readx(ibuf, ph.c_len);
obuf.allocForUncompression(ph.u_len);
decompress(ibuf, obuf);
Filter ft(ph.level);
ft.init(ph.filter, 0);
ft.cto = (unsigned char) ph.filter_cto;
ft.unfilter(obuf, ph.u_len);
fo->write(obuf, ph.u_len);
obuf.dealloc();
ibuf.dealloc();
fi->seek(p_note1->sh_offset, SEEK_SET);
fi->readx(&word, sizeof(word));
ph.u_len = word;
ph.c_len = p_note1->sh_size - sizeof(word);
ibuf.alloc(ph.c_len);
fi->readx(ibuf, p_note1->sh_size - sizeof(ph.u_len));
obuf.allocForUncompression(ph.u_len);
decompress(ibuf, obuf, false);
fo->write(obuf, ph.u_len);
obuf.dealloc();
ibuf.dealloc();
ph = ph_tmp;
}
/*************************************************************************
//
**************************************************************************/
const int *PackVmlinuxI386::getCompressionMethods(int method, int level) const
{
return Packer::getDefaultCompressionMethods_le32(method, level);
}
const int *PackVmlinuxI386::getFilters() const
{
static const int filters[] = {
0x49, 0x46,
FT_END };
return filters;
}
const int *PackVmlinuxARMEL::getCompressionMethods(int method, int level) const
{
return Packer::getDefaultCompressionMethods_8(method, level);
}
const int *PackVmlinuxARMEB::getCompressionMethods(int method, int level) const
{
return Packer::getDefaultCompressionMethods_8(method, level);
}
const int *PackVmlinuxPPC32::getCompressionMethods(int method, int level) const
{
// No real dependency on LE32.
return Packer::getDefaultCompressionMethods_le32(method, level);
}
const int *PackVmlinuxPPC64LE::getCompressionMethods(int method, int level) const
{
// No real dependency on LE32.
return Packer::getDefaultCompressionMethods_le32(method, level);
}
const int *PackVmlinuxARMEL::getFilters() const
{
static const int f50[] = { 0x50, FT_END };
return f50;
}
const int *PackVmlinuxARMEB::getFilters() const
{
static const int f51[] = { 0x51, FT_END };
return f51;
}
const int *PackVmlinuxPPC32::getFilters() const
{
static const int fd0[] = { 0xd0, FT_END };
return fd0;
}
const int *PackVmlinuxPPC64LE::getFilters() const
{
static const int fd0[] = { 0xd0, FT_END };
return fd0;
}
//
// Examples as of 2004-07-16 [readelf --segments vmlinux # before fiddling]:
//
//----- kernel-2.6.7 plain [defconfig?]
//Program Headers(2):
// Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
// LOAD 0x001000 0x00100000 0x00100000 0x1c7e61 0x1c7e61 R E 0x1000
// LOAD 0x1c8e64 0x002c8e64 0x002c8e64 0x00000 0x00000 RW 0x1000
//
//----- kernel-2.6.7-1.488 Fedora Core 3 test 1
//Program Headers(5):
// Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
// LOAD 0x001000 0x02100000 0x02100000 0x202246 0x202246 R E 0x1000
// LOAD 0x204000 0xffff3000 0x02303000 0x00664 0x00664 R E 0x1000
// LOAD 0x205000 0x02304000 0x02304000 0x43562 0x43562 R 0x1000
// LOAD 0x249000 0x02348000 0x02348000 0x81800 0xcb0fc RWE 0x1000
// STACK 0x000000 0x00000000 0x00000000 0x00000 0x00000 RWE 0x4
//
//----- kernel-2.6.18-1.2778 Fedora Core 6 test 3
//Program Headers(3)
// Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
// LOAD 0x001000 0xc0400000 0x00400000 0x279820 0x279820 R E 0x1000
// LOAD 0x27b000 0xc067a000 0x0067a000 0x10ee64 0x1b07e8 RWE 0x1000
// NOTE 0x000000 0x00000000 0x00000000 0x00000 0x00000 R 0x4
bool PackVmlinuxI386::is_valid_e_entry(Addr e_entry)
{
return 0==(0x000fffff & e_entry); // entry on whole 1 MiB
}
Linker* PackVmlinuxI386::newLinker() const
{
return new ElfLinkerX86;
}
void PackVmlinuxI386::buildLoader(const Filter *ft)
{
// prepare loader
initLoader(stub_i386_linux_kernel_vmlinux, sizeof(stub_i386_linux_kernel_vmlinux));
addLoader("LINUX000",
(0x40==(0xf0 & ft->id)) ? "LXCKLLT1" : (ft->id ? "LXCALLT1" : ""),
"LXMOVEUP",
getDecompressorSections(),
NULL
);
if (ft->id) {
assert(ft->calls > 0);
if (0x40==(0xf0 & ft->id)) {
addLoader("LXCKLLT9", NULL);
}
else {
addLoader("LXCALLT9", NULL);
}
addFilter32(ft->id);
}
addLoader("LINUX990",
((ph.first_offset_found == 1) ? "LINUX991" : ""),
"LINUX992,IDENTSTR,UPX1HEAD", NULL);
}
void PackVmlinuxAMD64::buildLoader(const Filter *ft)
{
// prepare loader
initLoader(stub_amd64_linux_kernel_vmlinux, sizeof(stub_amd64_linux_kernel_vmlinux));
addLoader("LINUX000",
(0x40==(0xf0 & ft->id)) ? "LXCKLLT1" : (ft->id ? "LXCALLT1" : ""),
"LXMOVEUP",
getDecompressorSections(),
NULL
);
if (ft->id) {
assert(ft->calls > 0);
if (0x40==(0xf0 & ft->id)) {
addLoader("LXCKLLT9", NULL);
}
else {
addLoader("LXCALLT9", NULL);
}
addFilter32(ft->id);
}
addLoader("LINUX990",
((ph.first_offset_found == 1) ? "LINUX991" : ""),
"LINUX992,IDENTSTR,UPX1HEAD", NULL);
}
bool PackVmlinuxARMEL::is_valid_e_entry(Addr e_entry)
{
return 0xc0008000==e_entry;
}
bool PackVmlinuxARMEB::is_valid_e_entry(Addr e_entry)
{
return 0xc0008000==e_entry;
}
bool PackVmlinuxPPC32::is_valid_e_entry(Addr e_entry)
{
return 0xc0000000==e_entry;
}
bool PackVmlinuxPPC64LE::is_valid_e_entry(Addr e_entry)
{
return 0xc0000000==e_entry;
}
Linker* PackVmlinuxARMEL::newLinker() const
{
return new ElfLinkerArmLE;
}
Linker* PackVmlinuxARMEB::newLinker() const
{
return new ElfLinkerArmBE;
}
Linker* PackVmlinuxPPC32::newLinker() const
{
return new ElfLinkerPpc32;
}
Linker* PackVmlinuxPPC64LE::newLinker() const
{
return new ElfLinkerPpc64le;
}
void PackVmlinuxARMEL::buildLoader(const Filter *ft)
{
// prepare loader
initLoader(stub_arm_v5a_linux_kernel_vmlinux, sizeof(stub_arm_v5a_linux_kernel_vmlinux));
addLoader("LINUX000", NULL);
if (ft->id) {
assert(ft->calls > 0);
addLoader("LINUX010", NULL);
}
addLoader("LINUX020", NULL);
if (ft->id) {
addFilter32(ft->id);
}
addLoader("LINUX030", NULL);
if (ph.method == M_NRV2E_8) addLoader("NRV2E", NULL);
else if (ph.method == M_NRV2B_8) addLoader("NRV2B", NULL);
else if (ph.method == M_NRV2D_8) addLoader("NRV2D", NULL);
else if (M_IS_LZMA(ph.method)) addLoader("LZMA_ELF00,LZMA_DEC10,LZMA_DEC30", NULL);
else throwBadLoader();
addLoader("IDENTSTR,UPX1HEAD", NULL);
}
void PackVmlinuxARMEB::buildLoader(const Filter *ft)
{
// prepare loader
initLoader(stub_armeb_v5a_linux_kernel_vmlinux, sizeof(stub_armeb_v5a_linux_kernel_vmlinux));
addLoader("LINUX000", NULL);
if (ft->id) {
assert(ft->calls > 0);
addLoader("LINUX010", NULL);
}
addLoader("LINUX020", NULL);
if (ft->id) {
addFilter32(ft->id);
}
addLoader("LINUX030", NULL);
if (ph.method == M_NRV2E_8) addLoader("NRV2E", NULL);
else if (ph.method == M_NRV2B_8) addLoader("NRV2B", NULL);
else if (ph.method == M_NRV2D_8) addLoader("NRV2D", NULL);
else if (M_IS_LZMA(ph.method)) addLoader("LZMA_ELF00,LZMA_DEC10,LZMA_DEC30", NULL);
else throwBadLoader();
addLoader("IDENTSTR,UPX1HEAD", NULL);
}
void PackVmlinuxPPC32::buildLoader(const Filter *ft)
{
// prepare loader
initLoader(stub_powerpc_linux_kernel_vmlinux, sizeof(stub_powerpc_linux_kernel_vmlinux));
addLoader("LINUX000", NULL);
if (ft->id) {
assert(ft->calls > 0);
addLoader("LINUX010", NULL);
}
addLoader("LINUX020", NULL);
if (ft->id) {
addFilter32(ft->id);
}
addLoader("LINUX030", NULL);
if (ph.method == M_NRV2E_LE32) addLoader("NRV2E,NRV_TAIL", NULL);
else if (ph.method == M_NRV2B_LE32) addLoader("NRV2B,NRV_TAIL", NULL);
else if (ph.method == M_NRV2D_LE32) addLoader("NRV2D,NRV_TAIL", NULL);
else if (M_IS_LZMA(ph.method)) addLoader("LZMA_ELF00,LZMA_DEC10,LZMA_DEC30", NULL);
else throwBadLoader();
if (hasLoaderSection("CFLUSH"))
addLoader("CFLUSH");
addLoader("IDENTSTR,UPX1HEAD", NULL);
}
static const
#include "stub/powerpc64le-linux.kernel.vmlinux.h"
void PackVmlinuxPPC64LE::buildLoader(const Filter *ft)
{
// prepare loader
initLoader(stub_powerpc64le_linux_kernel_vmlinux, sizeof(stub_powerpc64le_linux_kernel_vmlinux));
addLoader("LINUX000", NULL);
if (ft->id) {
assert(ft->calls > 0);
addLoader("LINUX010", NULL);
}
addLoader("LINUX020", NULL);
if (ft->id) {
addFilter32(ft->id);
}
addLoader("LINUX030", NULL);
if (ph.method == M_NRV2E_LE32) addLoader("NRV2E,NRV_TAIL", NULL);
else if (ph.method == M_NRV2B_LE32) addLoader("NRV2B,NRV_TAIL", NULL);
else if (ph.method == M_NRV2D_LE32) addLoader("NRV2D,NRV_TAIL", NULL);
else if (M_IS_LZMA(ph.method)) addLoader("LZMA_ELF00,LZMA_DEC10,LZMA_DEC30", NULL);
else throwBadLoader();
if (hasLoaderSection("CFLUSH"))
addLoader("CFLUSH");
addLoader("IDENTSTR,UPX1HEAD", NULL);
}
static const
#include "stub/i386-linux.kernel.vmlinux-head.h"
static const
#include "stub/amd64-linux.kernel.vmlinux-head.h"
static const
#include "stub/arm.v5a-linux.kernel.vmlinux-head.h"
static const
#include "stub/armeb.v5a-linux.kernel.vmlinux-head.h"
static const
#include "stub/powerpc-linux.kernel.vmlinux-head.h"
unsigned PackVmlinuxI386::write_vmlinux_head(
OutputFile *fo,
Shdr *stxt
)
{
// COMPRESSED_LENGTH
fo->write(&stub_i386_linux_kernel_vmlinux_head[0],
sizeof(stub_i386_linux_kernel_vmlinux_head)-(1+ 4) +1);
TE32 tmp_u32; tmp_u32 = ph.c_len; fo->write(&tmp_u32, 4);
stxt->sh_size += sizeof(stub_i386_linux_kernel_vmlinux_head);
return sizeof(stub_i386_linux_kernel_vmlinux_head);
}
unsigned PackVmlinuxAMD64::write_vmlinux_head(
OutputFile *fo,
Shdr *stxt
)
{
// COMPRESSED_LENGTH
fo->write(&stub_amd64_linux_kernel_vmlinux_head[0],
sizeof(stub_amd64_linux_kernel_vmlinux_head)-(1+ 4) +1);
TE32 tmp_u32; tmp_u32 = ph.c_len; fo->write(&tmp_u32, 4);
printf(" Compressed length=0x%x\n", ph.c_len);
printf("UnCompressed length=0x%x\n", ph.u_len);
stxt->sh_size += sizeof(stub_amd64_linux_kernel_vmlinux_head);
return sizeof(stub_amd64_linux_kernel_vmlinux_head);
}
void PackVmlinuxARMEL::defineDecompressorSymbols()
{
super::defineDecompressorSymbols();
linker->defineSymbol( "COMPRESSED_LENGTH", ph.c_len);
linker->defineSymbol("UNCOMPRESSED_LENGTH", ph.u_len);
linker->defineSymbol("METHOD", ph.method);
}
void PackVmlinuxARMEB::defineDecompressorSymbols()
{
super::defineDecompressorSymbols();
linker->defineSymbol( "COMPRESSED_LENGTH", ph.c_len);
linker->defineSymbol("UNCOMPRESSED_LENGTH", ph.u_len);
linker->defineSymbol("METHOD", ph.method);
}
void PackVmlinuxPPC32::defineDecompressorSymbols()
{
super::defineDecompressorSymbols();
// linker->defineSymbol( "COMPRESSED_LENGTH", ph.c_len);
// linker->defineSymbol("UNCOMPRESSED_LENGTH", ph.u_len);
// linker->defineSymbol("METHOD", ph.method);
}
void PackVmlinuxPPC64LE::defineDecompressorSymbols()
{
super::defineDecompressorSymbols();
// linker->defineSymbol( "COMPRESSED_LENGTH", ph.c_len);
// linker->defineSymbol("UNCOMPRESSED_LENGTH", ph.u_len);
// linker->defineSymbol("METHOD", ph.method);
}
void PackVmlinuxI386::defineDecompressorSymbols()
{
super::defineDecompressorSymbols();
linker->defineSymbol("ENTRY_POINT", phdri[0].p_paddr);
linker->defineSymbol("PHYSICAL_START", phdri[0].p_paddr);
}
void PackVmlinuxAMD64::defineDecompressorSymbols()
{
super::defineDecompressorSymbols();
// We assume a 32-bit boot loader, so we use the 32-bit convention
// of "enter at the beginning" (startup_32). The 64-bit convention
// would be to use ehdri.e_entry (startup_64).
linker->defineSymbol("ENTRY_POINT", (unsigned) phdri[0].p_paddr);
linker->defineSymbol("PHYSICAL_START", (unsigned) phdri[0].p_paddr);
}
unsigned PackVmlinuxARMEL::write_vmlinux_head(
OutputFile *fo,
Shdr *stxt
)
{
// First word from vmlinux-head.S
fo->write(&stub_arm_v5a_linux_kernel_vmlinux_head[0], 4);
// Second word
TE32 tmp_u32;
unsigned const t = (0xff000000 &
BeLePolicy::get32(&stub_arm_v5a_linux_kernel_vmlinux_head[4]))
| (0x00ffffff & (0u - 1 + ((3+ ph.c_len)>>2)));
tmp_u32 = t;
fo->write(&tmp_u32, 4);
stxt->sh_addralign = 4;
stxt->sh_size += sizeof(stub_arm_v5a_linux_kernel_vmlinux_head);
return sizeof(stub_arm_v5a_linux_kernel_vmlinux_head);
}
unsigned PackVmlinuxARMEB::write_vmlinux_head(
OutputFile *fo,
Shdr *stxt
)
{
// First word from vmlinux-head.S
fo->write(&stub_armeb_v5a_linux_kernel_vmlinux_head[0], 4);
// Second word
TE32 tmp_u32;
unsigned const t = (0xff000000 &
BeLePolicy::get32(&stub_armeb_v5a_linux_kernel_vmlinux_head[4]))
| (0x00ffffff & (0u - 1 + ((3+ ph.c_len)>>2)));
tmp_u32 = t;
fo->write(&tmp_u32, 4);
stxt->sh_addralign = 4;
stxt->sh_size += sizeof(stub_armeb_v5a_linux_kernel_vmlinux_head);
return sizeof(stub_armeb_v5a_linux_kernel_vmlinux_head);
}
unsigned PackVmlinuxPPC32::write_vmlinux_head(
OutputFile * /*fo*/,
Shdr * /*stxt*/
)
{
return 0;
}
unsigned PackVmlinuxPPC64LE::write_vmlinux_head(
OutputFile * /*const fo*/,
Shdr * /*const stxt*/
)
{
return 0;
}
bool PackVmlinuxARMEL::has_valid_vmlinux_head()
{
TE32 buf[2];
fi->seek(p_text->sh_offset + sizeof(stub_arm_v5a_linux_kernel_vmlinux_head) -8, SEEK_SET);
fi->readx(buf, sizeof(buf));
//unsigned const word0 = buf[0];
unsigned const word1 = buf[1];
if (0xeb==(word1>>24)
&& (0x00ffffff& word1)==(0u - 1 + ((3+ ph.c_len)>>2))) {
return true;
}
return false;
}
bool PackVmlinuxARMEB::has_valid_vmlinux_head()
{
TE32 buf[2];
fi->seek(p_text->sh_offset + sizeof(stub_armeb_v5a_linux_kernel_vmlinux_head) -8, SEEK_SET);
fi->readx(buf, sizeof(buf));
//unsigned const word0 = buf[0];
unsigned const word1 = buf[1];
if (0xeb==(word1>>24)
&& (0x00ffffff& word1)==(0u - 1 + ((3+ ph.c_len)>>2))) {
return true;
}
return false;
}
bool PackVmlinuxPPC32::has_valid_vmlinux_head()
{
TE32 buf[2];
fi->seek(p_text->sh_offset + sizeof(stub_powerpc_linux_kernel_vmlinux_head) -8, SEEK_SET);
fi->readx(buf, sizeof(buf));
//unsigned const word0 = buf[0];
unsigned const word1 = buf[1];
if (0xeb==(word1>>24)
&& (0x00ffffff& word1)==(0u - 1 + ((3+ ph.c_len)>>2))) {
return true;
}
return false;
}
#include "stub/powerpc64le-linux.kernel.vmlinux-head.h"
bool PackVmlinuxPPC64LE::has_valid_vmlinux_head()
{
TE64 buf[2];
fi->seek(p_text->sh_offset + sizeof(stub_powerpc64le_linux_kernel_vmlinux_head) -8, SEEK_SET);
fi->readx(buf, sizeof(buf));
//unsigned const word0 = buf[0];
unsigned const word1 = buf[1];
if (0xeb==(word1>>24)
&& (0x00ffffff& word1)==(0u - 1 + ((3+ ph.c_len)>>2))) {
return true;
}
return false;
}
bool PackVmlinuxI386::has_valid_vmlinux_head()
{
unsigned char buf[5];
fi->seek(p_text->sh_offset + sizeof(stub_i386_linux_kernel_vmlinux_head) -5, SEEK_SET);
fi->readx(&buf[0], 5);
if (0xE8!=buf[0] || BeLePolicy::get32(&buf[1]) != ph.c_len)
{
return false;
}
return true;
}
bool PackVmlinuxAMD64::has_valid_vmlinux_head()
{
unsigned char buf[5];
fi->seek(p_text->sh_offset + sizeof(stub_amd64_linux_kernel_vmlinux_head) -5, SEEK_SET);
fi->readx(&buf[0], 5);
if (0xE8!=buf[0] || BeLePolicy::get32(&buf[1]) != ph.c_len)
{
return false;
}
return true;
}
/*************************************************************************
//
**************************************************************************/
const int *PackVmlinuxAMD64::getCompressionMethods(int method, int level) const
{
return Packer::getDefaultCompressionMethods_le32(method, level);
}
const int *PackVmlinuxAMD64::getFilters() const
{
static const int filters[] = {
0x49, 0x46,
-1 };
return filters;
}
bool PackVmlinuxAMD64::is_valid_e_entry(Addr e_entry)
{
return 0x200000<=e_entry; // 2 MiB
}
Linker* PackVmlinuxAMD64::newLinker() const
{
return new ElfLinkerX86;
}
// instantiate instances
template class PackVmlinuxBase<ElfClass_LE32>;
template class PackVmlinuxBase<ElfClass_BE32>;
template class PackVmlinuxBase<ElfClass_LE64>;
/* vim:set ts=4 sw=4 et: */
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