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filter 0x51 (ARM call trick, big-endian at compress time)

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This commit is contained in:
John Reiser
2006-06-16 06:49:37 -07:00
parent fa702b48e3
commit fd2b9a6e21
5 changed files with 115 additions and 67 deletions
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src/p_lx_elf.cpp
+88 -58
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@@ -625,53 +625,16 @@ ehdr_lebe(Elf_LE32_Ehdr *const ehdr_le, Elf_BE32_Ehdr const *const ehdr_be)
ehdr_le->e_shstrndx = ehdr_be->e_shstrndx;
}
int
PackLinuxElf32::ARM_buildLoader(const Filter *ft, void (*fix_ehdr)(void *, void const *))
{
unsigned const sz_loader = sizeof(linux_elf32arm_loader);
unsigned const sz_fold = sizeof(linux_elf32arm_fold);
if (this->ei_data
== ((Elf32_Ehdr const *)linux_elf32arm_fold)->e_ident[Elf32_Ehdr::EI_DATA] ) {
return buildLinuxLoader(linux_elf32arm_loader, sz_loader,
linux_elf32arm_fold, sz_fold, ft );
}
else {
// linux_elf32arm_loader[] is all instructions, except for two strings
// at the end: the copyright message, and the SELinux message.
// The copyright message begins and ends with '\n', and the SELinux
// message ends with '\n'. So copy back to the third '\n' from the end,
// and apply brev() only before that point.
MemBuffer brev_loader(sz_loader);
MemBuffer brev_fold (sz_fold);
int nl = 0;
int j;
for (j= sz_loader; --j>=0; ) {
unsigned char const c = linux_elf32arm_loader[j];
brev_loader[j] = c;
if ('\n'==c) {
if (3==++nl) {
break;
}
}
}
brev(brev_loader, linux_elf32arm_loader, j);
brev(brev_fold, linux_elf32arm_fold, sz_fold);
fix_ehdr(brev_fold.getVoidPtr(), (void const *)linux_elf32arm_fold);
return buildLinuxLoader(brev_loader, sz_loader, brev_fold, sz_fold, ft);
}
}
int
PackLinuxElf32armBe::buildLoader(Filter const *ft)
{
return ARM_buildLoader(ft, (void (*)(void*, const void*))ehdr_bele);
return ARM_buildLoader(ft, true);
}
int
PackLinuxElf32armLe::buildLoader(Filter const *ft)
{
return ARM_buildLoader(ft, (void (*)(void*, const void*))ehdr_lebe);
return ARM_buildLoader(ft, false);
}
static const
@@ -1024,18 +987,20 @@ void PackLinuxElf32x86::pack1(OutputFile *fo, Filter &ft)
generateElfHdr(fo, linux_i386elf_fold, getbrk(phdri, ehdri.e_phnum) );
}
void PackLinuxElf32::ARM_pack1(OutputFile *fo, void (*fix_ehdr)(void *, void const *))
void PackLinuxElf32::ARM_pack1(OutputFile *fo, bool const isBE)
{
Elf32_Ehdr const *const fold = (Elf32_Ehdr const *)&linux_elf32arm_fold;
cprElfHdr3 h3;
// We need Elf32_Ehdr and Elf32_Phdr with the correct byte gender.
// We need Elf32_Ehdr and Elf32_Phdr with byte gender of target.
// The stub may have been compiled differently.
if (this->ei_data==fold->e_ident[Elf32_Ehdr::EI_DATA]) {
memcpy(&h3, (void const *)linux_elf32arm_fold,
sizeof(Elf32_Ehdr) + 2*sizeof(Elf32_Phdr) );
}
else {
fix_ehdr((void *)&h3.ehdr, (void const *)linux_elf32arm_fold);
(isBE ? (void (*)(void *, void const *))ehdr_bele
: (void (*)(void *, void const *))ehdr_lebe)
((void *)&h3.ehdr, (void const *)linux_elf32arm_fold);
brev((unsigned char *)&h3.phdr[0],
sizeof(Elf32_Ehdr) + (unsigned char const *)&linux_elf32arm_fold,
3*sizeof(Elf32_Phdr) );
@@ -1046,13 +1011,13 @@ void PackLinuxElf32::ARM_pack1(OutputFile *fo, void (*fix_ehdr)(void *, void con
void PackLinuxElf32armLe::pack1(OutputFile *fo, Filter &ft)
{
super::pack1(fo, ft);
ARM_pack1(fo, (void (*)(void *, void const *))ehdr_lebe);
ARM_pack1(fo, false);
}
void PackLinuxElf32armBe::pack1(OutputFile *fo, Filter &ft) // FIXME
{
super::pack1(fo, ft);
ARM_pack1(fo, (void (*)(void *, void const *))ehdr_bele);
ARM_pack1(fo, true);
}
void PackLinuxElf32ppc::pack1(OutputFile *fo, Filter &ft)
@@ -1371,6 +1336,85 @@ void PackLinuxElf64amd::pack3(OutputFile *fo, Filter &ft)
#include "bele.h"
using namespace NBELE;
// Filter 0x50, 0x51 assume HostPolicy::isLE
static const int *
ARM_getFilters(bool const isBE)
{
static const int f50[] = { 0x50, -1 };
static const int f51[] = { 0x51, -1 };
if (HostPolicy::isBE ^ isBE)
return f51;
return f50;
}
const int *
PackLinuxElf32armBe::getFilters() const
{
return ARM_getFilters(true);
}
const int *
PackLinuxElf32armLe::getFilters() const
{
return ARM_getFilters(false);
}
int
PackLinuxElf32::ARM_buildLoader(const Filter *ft, bool const isBE)
{
unsigned const sz_loader = sizeof(linux_elf32arm_loader);
unsigned const sz_fold = sizeof(linux_elf32arm_fold);
// Was ARM code assembled for same endianness as the target?
bool const asm_brev = (this->ei_data
!= ((Elf32_Ehdr const *)linux_elf32arm_fold)->e_ident[Elf32_Ehdr::EI_DATA] );
MemBuffer tmp_fold(sz_fold);
memcpy(tmp_fold, linux_elf32arm_fold, sz_fold);
// 0xe3530050 is "cmp fid,#0x50" with fid .req r3
if (HostPolicy::isBE ^ isBE) { // change filter 0x50 to filter 0x51
if (HostPolicy::isBE ^ isBE ^ asm_brev) { // find 0xe3530050 big-endian
checkPatch(NULL,0,0,0); // reset
patch_be32(tmp_fold, sz_fold, "\xe3\x53\x00\x50", 0xe3530051);
checkPatch(NULL,0,0,0); // reset
}
else { // find 0xe3530050 little-endian
checkPatch(NULL,0,0,0); // reset
patch_le32(tmp_fold, sz_fold, "\x50\x00\x53\xe3", 0xe3530051);
checkPatch(NULL,0,0,0); // reset
}
}
if (!asm_brev) { // was assembled to match target
return buildLinuxLoader(linux_elf32arm_loader, sz_loader,
tmp_fold, sz_fold, ft );
}
else { // was assembled brev() from target
// linux_elf32arm_loader[] is all instructions, except for two strings
// at the end: the copyright message, and the SELinux message.
// The copyright message begins and ends with '\n', and the SELinux
// message ends with '\n'. So copy back to the third '\n' from the end,
// and apply brev() only before that point.
MemBuffer brev_loader(sz_loader);
int nl = 0;
int j;
for (j= sz_loader; --j>=0; ) {
unsigned char const c = linux_elf32arm_loader[j];
brev_loader[j] = c;
if ('\n'==c) {
if (3==++nl) {
break;
}
}
}
brev(brev_loader, linux_elf32arm_loader, j);
(isBE ? (void (*)(void *, void const *))ehdr_bele
: (void (*)(void *, void const *))ehdr_lebe)
(tmp_fold.getVoidPtr(), (void const *)linux_elf32arm_fold);
return buildLinuxLoader(brev_loader, sz_loader, tmp_fold, sz_fold, ft);
}
}
void PackLinuxElf32::ARM_pack3(OutputFile *fo, Filter &ft, bool isBE)
{
unsigned const hlen = sz_elf_hdrs + sizeof(l_info) + sizeof(p_info);
@@ -1803,20 +1847,6 @@ PackLinuxElf32armBe::~PackLinuxElf32armBe()
{
}
const int *
PackLinuxElf32armLe::getFilters() const
{
static const int filters[] = { 0x50, -1 };
return filters;
}
const int *
PackLinuxElf32armBe::getFilters() const
{
static const int filters[] = { 0x50, -1 };
return filters;
}
unsigned
PackLinuxElf32::elf_get_offset_from_address(unsigned const addr) const
{