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MemBuffer lowmem; for shlib, especially android

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modified:   p_lx_elf.cpp
	modified:   p_lx_elf.h
This commit is contained in:
John Reiser 2018-01-21 14:03:52 -08:00
parent 3623199e8d
commit 7d2913709c
2 changed files with 38 additions and 40 deletions
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72
src/p_lx_elf.cpp
View File

@ -478,6 +478,8 @@ off_t PackLinuxElf32::pack3(OutputFile *fo, Filter &ft)
off_t PackLinuxElf64::pack3(OutputFile *fo, Filter &ft)
{
unsigned flen = super::pack3(fo, ft); // loader follows compressed PT_LOADs
// NOTE: PackLinuxElf::pack3 adjusted xct_off for the extra page
unsigned v_hole = sz_pack2 + lsize;
set_te64(&elfout.phdr[0].p_filesz, v_hole);
set_te64(&elfout.phdr[0].p_memsz, v_hole);
@ -522,7 +524,8 @@ off_t PackLinuxElf64::pack3(OutputFile *fo, Filter &ft)
set_te32(&elfout.phdr[1].p_flags, Elf32_Phdr::PF_W|Elf32_Phdr::PF_R);
}
if (0!=xct_off) { // shared library
Elf64_Phdr *phdr = phdro;
Elf64_Phdr *phdr = (Elf64_Phdr *)lowmem.subref(
"bad e_phoff", e_phoff, e_phnum * sizeof(Elf64_Phdr));
unsigned off = fo->st_size();
unsigned off_init = 0; // where in file
upx_uint64_t va_init = sz_pack2; // virtual address
@ -592,7 +595,8 @@ off_t PackLinuxElf64::pack3(OutputFile *fo, Filter &ft)
}
if (opt->o_unix.android_shlib) {
// Update {DYNAMIC}.sh_offset by so_slide.
Elf64_Shdr *shdr = shdro;
Elf64_Shdr *shdr = (Elf64_Shdr *)lowmem.subref(
"bad e_shoff", xct_off - asl_delta, e_shnum * sizeof(Elf64_Shdr));
for (unsigned j = 0; j < e_shnum; ++shdr, ++j) {
unsigned sh_type = get_te32(&shdr->sh_type);
if (Elf64_Shdr::SHT_DYNAMIC == sh_type) {
@ -601,7 +605,6 @@ off_t PackLinuxElf64::pack3(OutputFile *fo, Filter &ft)
fo->seek((j * sizeof(Elf64_Shdr)) + xct_off - asl_delta, SEEK_SET);
fo->rewrite(shdr, sizeof(*shdr));
fo->seek(0, SEEK_END);
break;
}
if (Elf64_Shdr::SHT_RELA == sh_type
&& n_jmp_slot
@ -677,7 +680,7 @@ void PackLinuxElf64::defineSymbols(Filter const *ft)
}
PackLinuxElf32::PackLinuxElf32(InputFile *f)
: super(f), phdro(NULL), phdri(NULL), shdro(NULL), shdri(NULL),
: super(f), phdri(NULL), shdri(NULL),
gnu_stack(NULL), note_body(NULL),
page_mask(~0u<<lg2_page),
dynseg(NULL), hashtab(NULL), gashtab(NULL), dynsym(NULL),
@ -694,13 +697,11 @@ PackLinuxElf32::PackLinuxElf32(InputFile *f)
PackLinuxElf32::~PackLinuxElf32()
{
delete[] shdro;
delete[] phdro;
delete[] note_body;
}
PackLinuxElf64::PackLinuxElf64(InputFile *f)
: super(f), phdro(NULL), phdri(NULL), shdro(NULL), shdri(NULL),
: super(f), phdri(NULL), shdri(NULL),
gnu_stack(NULL), note_body(NULL),
page_mask(~0ull<<lg2_page),
dynseg(NULL), hashtab(NULL), gashtab(NULL), dynsym(NULL),
@ -2620,7 +2621,8 @@ void PackLinuxElf32::pack1(OutputFile *fo, Filter & /*ft*/)
}
// .p_filesz,.p_memsz are updated in ::pack3
}
fo->rewrite(phdro, e_phnum * sizeof(Elf32_Phdr)); // adjacent to Ehdr
// FIXME
fo->rewrite(phdri, e_phnum * sizeof(Elf32_Phdr)); // adjacent to Ehdr
// Relocate Shdr; and Rela, Rel (below xct_off)
Elf32_Shdr *shdr = shdri;
@ -2872,10 +2874,12 @@ void PackLinuxElf64::pack1(OutputFile *fo, Filter & /*ft*/)
progid = 0; // getRandomId(); not useful, so do not clutter
if (0!=xct_off) { // shared library
phdro = new Elf64_Phdr[e_phnum];
memcpy(phdro, phdri, e_phnum * sizeof(Elf64_Phdr));
sz_elf_hdrs = sizeof(ehdri) + sz_phdrs + e_shnum * sizeof(Elf64_Shdr);
fo->write(file_image, xct_off); // before the first SHF_EXECINSTR (typ ".plt")
sz_elf_hdrs = sizeof(ehdri) + sz_phdrs;
lowmem.alloc(xct_off + (!opt->o_unix.android_shlib
? 0
: e_shnum * sizeof(Elf64_Shdr)));
memcpy(lowmem, file_image, xct_off); // android omits Shdr here
fo->write(lowmem, xct_off); // < SHF_EXECINSTR (typ: in .plt or .init)
if (opt->o_unix.android_shlib) {
// In order to pacify the runtime linker on Android "O" ("Oreo"),
// we will splice-in a 4KiB page that contains an "extra" copy
@ -2902,8 +2906,8 @@ void PackLinuxElf64::pack1(OutputFile *fo, Filter & /*ft*/)
// Relocate dynsym (DT_SYMTAB) which is below xct_va
upx_uint64_t const off_dynsym = get_te64(&sec_dynsym->sh_offset);
upx_uint64_t const sz_dynsym = get_te64(&sec_dynsym->sh_size);
Elf64_Sym *dyntym = new Elf64_Sym[sz_dynsym / sizeof(Elf64_Sym)];
memcpy(dyntym, dynsym, sz_dynsym);
Elf64_Sym *dyntym = (Elf64_Sym *)lowmem.subref(
"bad dynsym", off_dynsym, sz_dynsym);
Elf64_Sym *sym = dyntym;
for (int j = sz_dynsym / sizeof(Elf64_Sym); --j>=0; ++sym) {
upx_uint64_t symval = get_te64(&sym->st_value);
@ -2914,13 +2918,12 @@ void PackLinuxElf64::pack1(OutputFile *fo, Filter & /*ft*/)
set_te64(&sym->st_value, asl_delta + symval);
}
}
fo->seek(off_dynsym, SEEK_SET);
fo->rewrite(dyntym, sz_dynsym);
// Relocate Phdr virtual addresses, but not physical offsets and sizes
unsigned char buf_notes[512]; memset(buf_notes, 0, sizeof(buf_notes));
unsigned len_notes = 0;
phdr = phdro;
phdr = (Elf64_Phdr *)lowmem.subref(
"bad e_phoff", e_phoff, e_phnum * sizeof(Elf64_Phdr));
for (unsigned j = 0; j < e_phnum; ++j, ++phdr) {
upx_uint64_t offset = get_te64(&phdr->p_offset);
if (xct_off <= offset) { // above the extra page
@ -2945,17 +2948,14 @@ void PackLinuxElf64::pack1(OutputFile *fo, Filter & /*ft*/)
}
// .p_filesz,.p_memsz are updated in ::pack3
}
set_te64(&ehdri.e_shoff, xct_off);
fo->seek(0, SEEK_SET);
fo->rewrite(&ehdri, sizeof(ehdri));
fo->rewrite(phdro, sz_phdrs); // adjacent to Ehdr
// Relocate Shdr; and Rela, Rel (below xct_off)
shdro = new Elf64_Shdr[e_shnum];
memcpy(shdro, shdri, e_shnum * sizeof(*shdro));
set_te64(&((Elf64_Ehdr *)&lowmem[0])->e_shoff, xct_off);
memcpy(&lowmem[xct_off], shdri, e_shnum * sizeof(Elf64_Ehdr));
Elf64_Shdr *const shdro = (Elf64_Shdr *)&lowmem[xct_off];
Elf64_Shdr *shdr = shdro;
upx_uint64_t sz_shstrtab = get_te64(&sec_strndx->sh_size);
for (int j = e_shnum; --j>=0; ++shdr) {
for (unsigned j = 0; j < e_shnum; ++j, ++shdr) {
unsigned sh_type = get_te32(&shdr->sh_type);
upx_uint64_t sh_size = get_te64(&shdr->sh_size);
upx_uint64_t sh_offset = get_te64(&shdr->sh_offset);
@ -2973,8 +2973,8 @@ void PackLinuxElf64::pack1(OutputFile *fo, Filter & /*ft*/)
}
n_jmp_slot = 0;
plt_off = ~0ull;
Elf64_Rela *const relb = new Elf64_Rela[sh_size / sh_entsize];
memcpy(relb, &file_image[sh_offset], sh_size);
Elf64_Rela *const relb = (Elf64_Rela *)lowmem.subref(
"bad Rela offset", sh_offset, sh_size);
Elf64_Rela *rela = relb;
for (int k = sh_size / sh_entsize; --k >= 0; ++rela) {
upx_uint64_t r_addend = get_te64(&rela->r_addend);
@ -3013,7 +3013,8 @@ void PackLinuxElf64::pack1(OutputFile *fo, Filter & /*ft*/)
snprintf(msg, sizeof(msg), "bad Rel.sh_entsize %lu", (long)sh_entsize);
throwCantPack(msg);
}
Elf64_Rel *rel = (Elf64_Rel *)(sh_offset + file_image);
Elf64_Rel *rel = (Elf64_Rel *)lowmem.subref(
"bad Rel sh_offset", sh_offset, sh_size);
for (int k = sh_size / sh_entsize; --k >= 0; ++rel) {
upx_uint64_t r_offset = get_te64(&rel->r_offset);
if (xct_off <= r_offset) {
@ -3028,11 +3029,9 @@ void PackLinuxElf64::pack1(OutputFile *fo, Filter & /*ft*/)
&& Elf64_Ehdr::EM_AARCH64 == e_machine
&& ( R_AARCH64_RELATIVE == r_type
|| R_AARCH64_JUMP_SLOT == r_type)) {
set_te64(&file_image[d], asl_delta + w);
set_te64(&file_image[d], asl_delta + w); // FIXME
}
}
fo->seek(sh_offset, SEEK_SET);
fo->rewrite(sh_offset + file_image, sh_size);
}
if (Elf64_Shdr::SHT_NOTE == sh_type) {
if (xct_off <= sh_offset) {
@ -3046,9 +3045,12 @@ void PackLinuxElf64::pack1(OutputFile *fo, Filter & /*ft*/)
set_te64(&shdro[get_te16(&ehdri.e_shstrndx)].sh_offset,
len_notes + e_shnum * sizeof(Elf64_Shdr) + xct_off);
// (Re-)write all changes below xct_off
fo->seek(0, SEEK_SET);
fo->rewrite(lowmem, xct_off);
// New copy of Shdr
fo->seek(xct_off, SEEK_SET);
Elf64_Shdr blank; blank = shdro[0];
Elf64_Shdr blank; memset(&blank, 0, sizeof(blank));
set_te64(&blank.sh_offset, xct_off); // hint for "upx -d"
fo->write(&blank, sizeof(blank));
fo->write(&shdro[1], (-1+ e_shnum) * sizeof(Elf64_Shdr));
@ -3487,8 +3489,7 @@ void PackLinuxElf32::pack4(OutputFile *fo, Filter &ft)
fo->seek(0, SEEK_SET);
if (0!=xct_off) { // shared library
fo->rewrite(&ehdri, sizeof(ehdri));
fo->rewrite(phdro, e_phnum * sizeof(*phdri));
fo->rewrite(&lowmem[0], sizeof(ehdri) + e_phnum * sizeof(*phdri));
fo->seek(sz_elf_hdrs, SEEK_SET);
fo->rewrite(&linfo, sizeof(linfo));
@ -3549,8 +3550,7 @@ void PackLinuxElf64::pack4(OutputFile *fo, Filter &ft)
fo->seek(0, SEEK_SET);
if (0!=xct_off) { // shared library
fo->rewrite(&ehdri, sizeof(ehdri));
fo->rewrite(phdro, e_phnum * sizeof(*phdro));
fo->rewrite(&lowmem[0], sizeof(ehdri) + e_phnum * sizeof(Elf64_Phdr));
fo->seek(sz_elf_hdrs, SEEK_SET);
fo->rewrite(&linfo, sizeof(linfo));
}

6
src/p_lx_elf.h
View File

@ -157,9 +157,8 @@ protected:
protected:
Elf32_Ehdr ehdri; // from input file
Elf32_Ehdr *phdro; // especially for shlib
MemBuffer lowmem; // especially for shlib
Elf32_Phdr *phdri; // for input file
Elf32_Shdr *shdro; // especial for shlib
Elf32_Shdr *shdri; // from input file
Elf32_Phdr const *gnu_stack; // propagate NX
unsigned e_phoff;
@ -284,9 +283,8 @@ protected:
protected:
Elf64_Ehdr ehdri; // from input file
Elf64_Phdr *phdro; // especially for shlib
MemBuffer lowmem; // especially for shlib
Elf64_Phdr *phdri; // for input file
Elf64_Shdr *shdro; // especial for shlib
Elf64_Shdr *shdri; // from input file
Elf64_Phdr const *gnu_stack; // propagate NX
upx_uint64_t e_phoff;