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

move stub escape hatch for shared library to end of .text [glibc-2.13.90]

Browse Source
This commit is contained in:
John Reiser
2011-06-02 07:18:50 -07:00
parent eea33f6019
commit 21924bf022
10 changed files with 2281 additions and 2265 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/p_lx_elf.cpp
+79 -80
View File
@@ -189,6 +189,17 @@ PackLinuxElf::~PackLinuxElf()
delete[] file_image; file_image = NULL;
}
// Swap the byte ranges fo[a to b] and fo[b to c].
static void swap_byte_ranges(OutputFile *fo, unsigned a, unsigned b, unsigned c)
{
MemBuffer buf(c - a);
fo->seek(a, SEEK_SET);
fo->readx(buf, c - a);
fo->seek(a, SEEK_SET);
fo->rewrite(&buf[b - a], c - b);
fo->rewrite(&buf[0], b - a);
}
void PackLinuxElf::pack3(OutputFile *fo, Filter &ft)
{
sz_pack2b = fpad4(fo); // after headers, all PT_LOAD, gaps
@@ -207,7 +218,7 @@ void PackLinuxElf::pack3(OutputFile *fo, Filter &ft)
fo->write(&disp, sizeof(disp));
len += sizeof(disp);
if (xct_off) {
if (xct_off) { // is_shlib
set_te32(&disp, elf_unsigned_dynamic(Elf32_Dyn::DT_INIT) - load_va);
fo->write(&disp, sizeof(disp));
len += sizeof(disp);
@@ -223,9 +234,15 @@ void PackLinuxElf::pack3(OutputFile *fo, Filter &ft)
sz_pack2 = len; // 0 mod 8
super::pack3(fo, ft); // append the decompressor
fpad4(fo);
set_te16(&linfo.l_lsize, up4(
get_te16(&linfo.l_lsize) + len - sz_pack2a));
len = fpad4(fo);
// Put the loader in the middle, after the compressed PT_LOADs
// and before the compressed gaps (and debuginfo!)
// As first written, loader is fo[sz_pack2b to len],
// and gaps and debuginfo are fo[sz_pack2a to sz_pack2b].
swap_byte_ranges(fo, sz_pack2a, sz_pack2b, len);
}
void PackLinuxElf32::pack3(OutputFile *fo, Filter &ft)
@@ -293,7 +310,7 @@ void PackLinuxElf32::pack3(OutputFile *fo, Filter &ft)
}
if (off_init) { // change DT_INIT.d_val
fo->seek(off_init, SEEK_SET);
va_init |= (Elf32_Ehdr::EM_ARM==e_machine);
va_init |= (Elf32_Ehdr::EM_ARM==e_machine); // THUMB mode
unsigned word; set_te32(&word, va_init);
fo->rewrite(&word, sizeof(word));
fo->seek(0, SEEK_END);
@@ -326,7 +343,7 @@ void PackLinuxElf64::pack3(OutputFile *fo, Filter &ft)
// Rotate to highest position, so it can be lopped
// by decrementing e_phnum.
memcpy((unsigned char *)ibuf, phdr, sizeof(*phdr));
memcpy(phdr, 1+phdr, j * sizeof(*phdr));
memmove(phdr, 1+phdr, j * sizeof(*phdr)); // overlapping
memcpy(&phdr[j], (unsigned char *)ibuf, sizeof(*phdr));
--phdr;
set_te16(&ehdri.e_phnum, --e_phnum);
@@ -1317,14 +1334,17 @@ bool PackLinuxElf32::canPack()
// Apparently glibc-2.13.90 insists on 0==e_ident[EI_PAD..15],
// so compressing shared libraries may be doomed anyway.
// 2011-06-01: stub.shlib-init.S works around by installing hatch
// at end of .text.
if (elf_find_dynamic(Elf32_Dyn::DT_INIT)) {
if (this->e_machine!=Elf32_Ehdr::EM_386)
goto abandon; // need stub: EM_ARM EM_MIPS EM_PPC
if (this->e_machine!=Elf32_Ehdr::EM_386
&& this->e_machine!=Elf32_Ehdr::EM_ARM)
goto abandon; // need stub: EM_MIPS EM_PPC
if (elf_has_dynamic(Elf32_Dyn::DT_TEXTREL)) {
shdri = NULL;
phdri = NULL;
throwCantPack("re-compile with -fPIC to remove DT_TEXTREL");
throwCantPack("DT_TEXTREL found; re-compile with -fPIC");
goto abandon;
}
Elf32_Shdr const *shdr = shdri;
@@ -1502,8 +1522,12 @@ PackLinuxElf64amd::canPack()
// and also requires ld-linux to behave.
if (elf_find_dynamic(Elf64_Dyn::DT_INIT)) {
if (elf_has_dynamic(Elf64_Dyn::DT_TEXTREL))
if (elf_has_dynamic(Elf64_Dyn::DT_TEXTREL)) {
shdri = NULL;
phdri = NULL;
throwCantPack("DT_TEXTREL found; re-compile with -fPIC");
goto abandon;
}
Elf64_Shdr const *shdr = shdri;
xct_va = ~0ull;
for (j= n_elf_shnum; --j>=0; ++shdr) {
@@ -1523,6 +1547,9 @@ PackLinuxElf64amd::canPack()
|| xct_va < elf_unsigned_dynamic(Elf64_Dyn::DT_VERDEF)
|| xct_va < elf_unsigned_dynamic(Elf64_Dyn::DT_VERSYM)
|| xct_va < elf_unsigned_dynamic(Elf64_Dyn::DT_VERNEEDED) ) {
phdri = NULL;
shdri = NULL;
throwCantPack("DT_ tag above stub");
goto abandon;
}
for ((shdr= shdri), (j= n_elf_shnum); --j>=0; ++shdr) {
@@ -1877,7 +1904,7 @@ PackLinuxElf64::generateElfHdr(
}
}
void PackLinuxElf32::pack1(OutputFile * /*fo*/, Filter & /*ft*/)
void PackLinuxElf32::pack1(OutputFile *fo, Filter & /*ft*/)
{
fi->seek(0, SEEK_SET);
fi->readx(&ehdri, sizeof(ehdri));
@@ -1921,40 +1948,38 @@ void PackLinuxElf32::pack1(OutputFile * /*fo*/, Filter & /*ft*/)
page_mask = ~0u<<lg2_page;
progid = 0; // getRandomId(); not useful, so do not clutter
if (0!=xct_off) { // shared library
fi->seek(0, SEEK_SET);
fi->readx(ibuf, xct_off);
sz_elf_hdrs = xct_off;
fo->write(ibuf, xct_off);
memset(&linfo, 0, sizeof(linfo));
fo->write(&linfo, sizeof(linfo));
}
}
void PackLinuxElf32x86::pack1(OutputFile *fo, Filter &ft)
{
super::pack1(fo, ft);
if (0!=xct_off) { // shared library
fi->seek(0, SEEK_SET);
fi->readx(ibuf, xct_off);
sz_elf_hdrs = xct_off - sizeof(l_info);
fo->write(ibuf, xct_off);
if (0!=xct_off) // shared library
return;
}
generateElfHdr(fo, stub_i386_linux_elf_fold,
getbrk(phdri, e_phnum) );
generateElfHdr(fo, stub_i386_linux_elf_fold, getbrk(phdri, e_phnum) );
}
void PackBSDElf32x86::pack1(OutputFile *fo, Filter &ft)
{
PackLinuxElf32::pack1(fo, ft);
if (0!=xct_off) // shared library
return;
generateElfHdr(fo, stub_i386_bsd_elf_fold, getbrk(phdri, e_phnum) );
}
void PackLinuxElf32armLe::pack1(OutputFile *fo, Filter &ft)
{
super::pack1(fo, ft);
if (0!=xct_off) { // shared library
fi->seek(0, SEEK_SET);
fi->readx(ibuf, xct_off);
sz_elf_hdrs = xct_off - sizeof(l_info);
fo->write(ibuf, xct_off);
if (0!=xct_off) // shared library
return;
}
unsigned const e_flags = get_te32(&ehdri.e_flags);
cprElfHdr3 h3;
if (Elf32_Ehdr::ELFOSABI_LINUX==ei_osabi) {
@@ -1972,6 +1997,8 @@ void PackLinuxElf32armLe::pack1(OutputFile *fo, Filter &ft)
void PackLinuxElf32armBe::pack1(OutputFile *fo, Filter &ft)
{
super::pack1(fo, ft);
if (0!=xct_off) // shared library
return;
unsigned const e_flags = get_te32(&ehdri.e_flags);
cprElfHdr3 h3;
memcpy(&h3, stub_armeb_linux_elf_fold, sizeof(Elf32_Ehdr) + 2*sizeof(Elf32_Phdr));
@@ -1982,6 +2009,8 @@ void PackLinuxElf32armBe::pack1(OutputFile *fo, Filter &ft)
void PackLinuxElf32mipsel::pack1(OutputFile *fo, Filter &ft)
{
super::pack1(fo, ft);
if (0!=xct_off) // shared library
return;
cprElfHdr3 h3;
memcpy(&h3, stub_mipsel_r3000_linux_elf_fold, sizeof(Elf32_Ehdr) + 2*sizeof(Elf32_Phdr));
generateElfHdr(fo, &h3, getbrk(phdri, e_phnum) );
@@ -1990,6 +2019,8 @@ void PackLinuxElf32mipsel::pack1(OutputFile *fo, Filter &ft)
void PackLinuxElf32mipseb::pack1(OutputFile *fo, Filter &ft)
{
super::pack1(fo, ft);
if (0!=xct_off) // shared library
return;
cprElfHdr3 h3;
memcpy(&h3, stub_mips_r3000_linux_elf_fold, sizeof(Elf32_Ehdr) + 2*sizeof(Elf32_Phdr));
generateElfHdr(fo, &h3, getbrk(phdri, e_phnum) );
@@ -1998,10 +2029,12 @@ void PackLinuxElf32mipseb::pack1(OutputFile *fo, Filter &ft)
void PackLinuxElf32ppc::pack1(OutputFile *fo, Filter &ft)
{
super::pack1(fo, ft);
if (0!=xct_off) // shared library
return;
generateElfHdr(fo, stub_powerpc_linux_elf_fold, getbrk(phdri, e_phnum) );
}
void PackLinuxElf64::pack1(OutputFile * /*fo*/, Filter & /*ft*/)
void PackLinuxElf64::pack1(OutputFile *fo, Filter & /*ft*/)
{
fi->seek(0, SEEK_SET);
fi->readx(&ehdri, sizeof(ehdri));
@@ -2044,20 +2077,23 @@ void PackLinuxElf64::pack1(OutputFile * /*fo*/, Filter & /*ft*/)
page_mask = ~0ull<<lg2_page;
progid = 0; // getRandomId(); not useful, so do not clutter
if (0!=xct_off) { // shared library
fi->seek(0, SEEK_SET);
fi->readx(ibuf, xct_off);
sz_elf_hdrs = xct_off;
fo->write(ibuf, xct_off);
memset(&linfo, 0, sizeof(linfo));
fo->write(&linfo, sizeof(linfo));
}
}
void PackLinuxElf64amd::pack1(OutputFile *fo, Filter &ft)
{
super::pack1(fo, ft);
if (0==xct_off) // main executable
generateElfHdr(fo, stub_amd64_linux_elf_fold, getbrk(phdri, e_phnum) );
else { // shared library
fi->seek(0, SEEK_SET);
fi->readx(ibuf, xct_off);
sz_elf_hdrs = xct_off - sizeof(l_info);
fo->write(ibuf, xct_off);
}
if (0!=xct_off) // shared library
return;
generateElfHdr(fo, stub_amd64_linux_elf_fold, getbrk(phdri, e_phnum) );
}
// Determine length of gap between PT_LOAD phdr[k] and closest PT_LOAD
@@ -2507,27 +2543,9 @@ void PackLinuxElf32mipsel::defineSymbols(Filter const * /*ft*/)
//linker->dumpSymbols(); // debug
}
// Swap the byte ranges fo[a to b] and fo[b to c].
static void swap_byte_ranges(OutputFile *fo, unsigned a, unsigned b, unsigned c)
{
MemBuffer buf(c - a);
fo->seek(a, SEEK_SET);
fo->readx(buf, c - a);
fo->seek(a, SEEK_SET);
fo->rewrite(&buf[b - a], c - b);
fo->rewrite(&buf[0], b - a);
}
void PackLinuxElf32::pack4(OutputFile *fo, Filter &ft)
{
overlay_offset = sz_elf_hdrs + sizeof(linfo);
unsigned len = fpad4(fo);
// Put the loader in the middle, after the compressed PT_LOADs
// and before the compressed gaps (and debuginfo!)
// As first written, loader is fo[sz_pack2b to len],
// and gaps and debuginfo are fo[sz_pack2a to sz_pack2b].
swap_byte_ranges(fo, sz_pack2a, sz_pack2b, len);
// Cannot pre-round .p_memsz. If .p_filesz < .p_memsz, then kernel
// tries to make .bss, which requires PF_W.
@@ -2551,16 +2569,10 @@ void PackLinuxElf32::pack4(OutputFile *fo, Filter &ft)
fo->seek(0, SEEK_SET);
if (0!=xct_off) { // shared library
ehdri.e_ident[12] = 0xcd; // INT 0x80 (syscall [munmap])
ehdri.e_ident[13] = 0x80;
ehdri.e_ident[14] = 0x61; // POPA
ehdri.e_ident[15] = 0xc3; // RET
if (Elf32_Ehdr::EM_ARM==e_machine) {
set_te16(&ehdri.e_ident[12], 0xdf00); // swi 0
set_te16(&ehdri.e_ident[14], 0xbdff); // pop {all regs}
}
fo->rewrite(&ehdri, sizeof(ehdri));
fo->rewrite(phdri, e_phnum * sizeof(*phdri));
fo->seek(sz_elf_hdrs, SEEK_SET);
fo->rewrite(&linfo, sizeof(linfo));
}
else {
unsigned const reloc = get_te32(&elfout.phdr[0].p_vaddr);
@@ -2583,13 +2595,6 @@ void PackLinuxElf32::pack4(OutputFile *fo, Filter &ft)
void PackLinuxElf64::pack4(OutputFile *fo, Filter &ft)
{
overlay_offset = sz_elf_hdrs + sizeof(linfo);
unsigned len = fpad4(fo);
// Put the loader in the middle, after the compressed PT_LOADs
// and before the compressed gaps (and debuginfo!)
// As first written, loader is fo[sz_pack2b to len],
// and gaps and debuginfo are fo[sz_pack2a to sz_pack2b].
swap_byte_ranges(fo, sz_pack2a, sz_pack2b, len);
// Cannot pre-round .p_memsz. If .p_filesz < .p_memsz, then kernel
// tries to make .bss, which requires PF_W.
@@ -2613,11 +2618,6 @@ void PackLinuxElf64::pack4(OutputFile *fo, Filter &ft)
fo->seek(0, SEEK_SET);
if (0!=xct_off) { // shared library
ehdri.e_ident[11] = 0x0f; // syscall [munmap]
ehdri.e_ident[12] = 0x05;
ehdri.e_ident[13] = 0x5f; // pop %rdi (arg1)
ehdri.e_ident[14] = 0x5e; // pop %rsi (arg2)
ehdri.e_ident[15] = 0xc3; // RET
fo->rewrite(&ehdri, sizeof(ehdri));
fo->rewrite(phdri, e_phnum * sizeof(*phdri));
}
@@ -2665,7 +2665,8 @@ void PackLinuxElf64::unpack(OutputFile *fo)
load_va = get_te64(&phdr0x.p_vaddr);
fi->seek(overlay_offset - sizeof(l_info), SEEK_SET);
fi->readx(&linfo, sizeof(linfo));
fi->readx(&linfo, sizeof(linfo));
lsize = get_te16(&linfo.l_lsize);
p_info hbuf; fi->readx(&hbuf, sizeof(hbuf));
unsigned orig_file_size = get_te32(&hbuf.p_filesize);
blocksize = get_te32(&hbuf.p_blocksize);
@@ -2709,7 +2710,6 @@ void PackLinuxElf64::unpack(OutputFile *fo)
}
}
}
lsize = get_te16(&linfo.l_lsize);
if (( (unsigned)(get_te64(&ehdri.e_entry) - load_va) + up4(lsize) +
ph.getPackHeaderSize() + sizeof(overlay_offset)) < up4(fi->st_size())) {
// Loader is not at end; skip past it.
@@ -3125,7 +3125,8 @@ void PackLinuxElf32::unpack(OutputFile *fo)
load_va = get_te32(&phdr0x.p_vaddr);
fi->seek(overlay_offset - sizeof(l_info), SEEK_SET);
fi->readx(&linfo, sizeof(linfo));
fi->readx(&linfo, sizeof(linfo));
lsize = get_te16(&linfo.l_lsize);
p_info hbuf; fi->readx(&hbuf, sizeof(hbuf));
unsigned orig_file_size = get_te32(&hbuf.p_filesize);
blocksize = get_te32(&hbuf.p_blocksize);
@@ -3138,9 +3139,7 @@ void PackLinuxElf32::unpack(OutputFile *fo)
ph.u_len = get_te32(&bhdr.sz_unc);
ph.c_len = get_te32(&bhdr.sz_cpr);
ph.filter_cto = bhdr.b_cto8;
bool const is_shlib = (ehdr->e_ident[12]==0xcd) // EM_386
|| (ehdr->e_ident[11]==0x0f) // EM_X86_64
|| (get_te16(&ehdr->e_ident[12])==0xdf00); // EM_ARM (thumb)
bool const is_shlib = (ehdr->e_shoff!=0);
// Peek at resulting Ehdr and Phdrs for use in controlling unpacking.
// Uncompress an extra time, and don't verify or update checksums.
@@ -3166,6 +3165,7 @@ void PackLinuxElf32::unpack(OutputFile *fo)
// Read enough to position the input for next unpackExtent.
fi->seek(0, SEEK_SET);
fi->readx(ibuf, overlay_offset + sizeof(hbuf) + szb_info + ph.c_len);
overlay_offset -= sizeof(linfo);
if (fo) {
fo->write(ibuf + ph.u_len, overlay_offset - ph.u_len);
}
@@ -3216,7 +3216,6 @@ void PackLinuxElf32::unpack(OutputFile *fo)
}
}
}
lsize = get_te16(&linfo.l_lsize);
if (( (unsigned)(get_te32(&ehdri.e_entry) - load_va) + up4(lsize) +
ph.getPackHeaderSize() + sizeof(overlay_offset)) < up4(fi->st_size())) {
// Loader is not at end; skip past it.