Master/upx
1
0
Fork 0
Code Issues Pull Requests Actions 1 Packages Projects Releases Wiki Activity

BvmlinuzI386 runtime-relocatable kernels

Browse Source
This commit is contained in:
John Reiser
2008-01-29 10:33:45 -08:00
parent 7f9c47176a
commit 54d0fef559
7 changed files with 3898 additions and 3513 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/p_vmlinz.cpp
+88 -14
View File
@@ -51,7 +51,7 @@ static const unsigned bzimage_offset = 0x100000;
**************************************************************************/
PackVmlinuzI386::PackVmlinuzI386(InputFile *f) :
super(f), physical_start(0x100000)
super(f), physical_start(0x100000), page_offset(0), config_physical_align(0)
{
bele = &N_BELE_RTP::le_policy;
COMPILE_TIME_ASSERT(sizeof(boot_sect_t) == 0x218);
@@ -124,6 +124,11 @@ int PackVmlinuzI386::readFileHeader()
}
static int is_pow2(unsigned const x)
{
return !(x & (-1+ x));
}
// read full kernel into obuf[], gzip-decompress into ibuf[],
// return decompressed size
int PackVmlinuzI386::decompressKernel()
@@ -133,9 +138,17 @@ int PackVmlinuzI386::decompressKernel()
fi->seek(0, SEEK_SET);
fi->readx(obuf, file_size);
char const *base = 0;
unsigned relocated = 0;
// See startup_32: in linux/arch/i386/boot/compressed/head.S
char const *p = (char const *)&obuf[setup_size];
for (int j= 0; j < 0x200; ++j, ++p) {
if (0==memcmp("\x8d\x83", p, 2) // leal d32(%ebx),%eax
&& 0==memcmp("\xff\xe0", 6+ p, 2) // jmp *%eax
) {
relocated = get_te32(2+ p);
}
if (0==memcmp("\xE8\x00\x00\x00\x00\x5D", p, 6)) {
// "call 1f; 1f: pop %ebp" determines actual execution address.
// linux-2.6.21 (spring 2007) and later; upx stub needs work
@@ -146,21 +159,45 @@ int PackVmlinuzI386::decompressKernel()
// subl $1b, %ebp # 32-bit immediate
// movl $LOAD_PHYSICAL_ADDR, %ebx
//
unsigned const cpa_0 = 1+ get_te32(16+ p);
unsigned const cpa_1 = get_te32(22+ p);
if (0==memcmp("\x81\xed", 6+ p, 2) // subl $imm.w,%ebp
&& 0==memcmp("\xbb", 12+ p, 1) ) { // movl $...,%ebx
physical_start = get_le32(13+ p);
&& 0==memcmp("\xbb", 12+ p, 1) ) { // movl $imm.w,%ebx
physical_start = get_te32(13+ p);
} else
if (0==memcmp("\x81\xed", 6+ p, 2) // subl $imm.w,%ebp
&& 0==memcmp("\x89\xeb", 12+ p, 2) // movl %ebp,%ebx
&& 0==memcmp("\x81\xc3", 14+ p, 2) // addl $imm.w,%ebx
&& 0==memcmp("\x81\xe3", 20+ p, 2) // andl $imm.w,%ebx
&& is_pow2(cpa_0) && -cpa_0==cpa_1) {
base = (5+ p) - get_te32(8+ p);
config_physical_align = cpa_0;
}
else {
throwCantPack("Relocatable kernel is not yet supported");
throwCantPack("Unrecognized relocatable kernel");
}
}
// Find "ljmp $__BOOT_CS,$__PHYSICAL_START" if any.
if (0==memcmp("\xEA\x00\x00", p, 3) && 0==(0xf & p[3]) && 0==p[4]) {
/* whole megabyte < 16MB */
physical_start = get_le32(1+ p);
physical_start = get_te32(1+ p);
break;
}
}
if (base && relocated) {
char const *p = relocated + base;
for (int j= 0; j < 0x200; ++j, ++p) {
if (0==memcmp("\x01\x9c\x0b", p, 3) // addl %ebx,d32(%ebx,%ecx)
) {
page_offset = - get_te32(3+ p);
}
if (0==memcmp("\x89\xeb", p, 2) // movl %ebp,%ebx
&& 0==memcmp("\x81\xeb", 2+ p, 2) // subl $imm32,%ebx
) {
physical_start = get_te32(4+ p);
}
}
}
checkAlreadyPacked(obuf + setup_size, UPX_MIN(file_size - setup_size, (off_t)1024));
@@ -376,7 +413,15 @@ void PackBvmlinuzI386::buildLoader(const Filter *ft)
{
// prepare loader
initLoader(stub_i386_linux_kernel_vmlinuz, sizeof(stub_i386_linux_kernel_vmlinuz));
addLoader("LINUZ000",
if (0!=page_offset) { // relocatable kernel
addLoader("LINUZ100,LINUZ110",
((0!=config_physical_align) ? "LINUZ120" : "LINUZ130"),
"LINUZ140,LZCUTPOI",
(ph.first_offset_found == 1 ? "LINUZ001" : ""),
NULL);
}
else {
addLoader("LINUZ000",
ph.first_offset_found == 1 ? "LINUZ001" : "",
(0x40==(0xf0 & ft->id)) ? "LZCKLLT1" : (ft->id ? "LZCALLT1" : ""),
"LBZIMAGE,IDENTSTR",
@@ -384,16 +429,15 @@ void PackBvmlinuzI386::buildLoader(const Filter *ft)
"UPX1HEAD", // 32 byte
"LZCUTPOI",
NULL);
// fake alignment for the start of the decompressor
linker->defineSymbol("LZCUTPOI", 0x1000);
}
// fake alignment for the start of the decompressor
linker->defineSymbol("LZCUTPOI", 0x1000);
addLoader(getDecompressorSections(), NULL);
addLoader(getDecompressorSections(),
NULL
);
if (ft->id)
{
assert(ft->calls > 0);
assert(ft->calls > 0);
if (0x40==(0xf0 & ft->id)) {
addLoader("LZCKLLT9", NULL);
}
@@ -402,7 +446,27 @@ void PackBvmlinuzI386::buildLoader(const Filter *ft)
}
addFilter32(ft->id);
}
addLoader("LINUZ990", NULL);
if (0!=page_offset) {
addLoader("LINUZ150", NULL);
unsigned const l_len = getLoaderSize();
unsigned const c_len = ALIGN_UP(ph.c_len, 4u);
unsigned const e_len = getLoaderSectionStart("LZCUTPOI");
linker->defineSymbol("compressed_length", c_len);
linker->defineSymbol("load_physical_address", physical_start); // FIXME
if (0!=config_physical_align) {
linker->defineSymbol("neg_config_physical_align", - config_physical_align);
}
linker->defineSymbol("neg_length_mov", - ALIGN_UP(c_len + l_len, 4u));
linker->defineSymbol("neg_page_offset", - page_offset);
//linker->defineSymbol("physical_start", physical_start);
linker->defineSymbol("unc_length", ph.u_len);
linker->defineSymbol("dec_offset", ph.overlap_overhead + e_len);
linker->defineSymbol("unc_offset", ph.overlap_overhead + ph.u_len - c_len);
addLoader("IDENTSTR,+40,UPX1HEAD", NULL);
}
else {
addLoader("LINUZ990", NULL);
}
}
@@ -472,8 +536,18 @@ void PackBvmlinuzI386::pack(OutputFile *fo)
bs->sys_size = (ALIGN_UP(lsize + c_len, 16u) / 16) & 0xffff;
fo->write(setup_buf, setup_buf.getSize());
fo->write(loader, e_len);
unsigned const e_pfx = (0==page_offset) ? 0 : getLoaderSectionStart("LINUZ110");
if (0!=page_offset) {
fo->write(loader, e_pfx);
}
else {
fo->write(loader, e_len);
}
fo->write(obuf, c_len);
if (0!=page_offset) {
fo->write(loader + e_pfx, e_len - e_pfx);
}
fo->write(loader + e_len, lsize - e_len);
#if 0
printf("%-13s: setup : %8ld bytes\n", getName(), (long) setup_buf.getSize());