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

--android-shlib preserves selected Elf32_Shdr

Browse Source 
32-bit only for now; also in wrong place for unpacking (-d)
	modified:   main.cpp
	modified:   options.h
	modified:   p_elf_enum.h
	modified:   p_lx_elf.cpp
	modified:   p_lx_elf.h
This commit is contained in:
John Reiser 2017-03-29 18:31:39 -07:00
parent 348173d3f1
commit 300d489408
5 changed files with 73 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
src/main.cpp
View File

@ -866,6 +866,9 @@ static int do_option(int optc, const char *arg)
case 675:
opt->o_unix.preserve_build_id = true;
break;
case 676:
opt->o_unix.android_shlib = true;
break;
case '\0':
return -1;
@ -1016,6 +1019,7 @@ static const struct mfx_option longopts[] =
{"openbsd", 0x10, 0, 669},
{"unmap-all-pages", 0x10, 0, 674}, // linux /proc/self/exe vanishes
{"preserve-build-id", 0, 0, 675},
{"android-shlib", 0, 0, 676},
// watcom/le
{"le", 0x10, 0, 620}, // produce LE output
// win32/pe

1
src/options.h
View File

@ -146,6 +146,7 @@ struct options_t {
bool unmap_all_pages; // thus /proc/self/exe vanishes
unsigned char osabi0; // replacement if 0==.e_ident[EI_OSABI]
bool preserve_build_id; // copy the build-id to the compressed binary
bool android_shlib; // keep some ElfXX_Shdr for dlopen()
} o_unix;
struct {
bool le;

2
src/p_elf_enum.h
View File

@ -123,6 +123,8 @@
SHT_GROUP = 17, /* Section group */
SHT_SYMTAB_SHNDX = 18, /* Extended section indeces */
SHT_GNU_LIBLIST = 0x6ffffff7 /* Prelink library list */
, SHT_LOOS = 0x60000000 /* LOcal OS; SHT_ANDROID_REL{,A} is +1, +2 */
};
enum { // sh_flags

72
src/p_lx_elf.cpp
View File

@ -344,8 +344,8 @@ void PackLinuxElf32::pack3(OutputFile *fo, Filter &ft)
unsigned off = fo->st_size();
unsigned off_init = 0; // where in file
unsigned va_init = sz_pack2; // virtual address
unsigned rel = 0;
unsigned old_dtinit = 0;
so_slide = 0;
for (int j = e_phnum; --j>=0; ++phdr) {
unsigned const len = get_te32(&phdr->p_filesz);
unsigned const ioff = get_te32(&phdr->p_offset);
@ -367,8 +367,8 @@ void PackLinuxElf32::pack3(OutputFile *fo, Filter &ft)
off += ~page_mask & (ioff - off);
fo->seek(off, SEEK_SET);
fo->write(ibuf, len);
rel = off - ioff;
set_te32(&phdr->p_offset, rel + ioff);
so_slide = off - ioff;
set_te32(&phdr->p_offset, so_slide + ioff);
}
else { // Change length of first PT_LOAD.
va_init += get_te32(&phdr->p_vaddr);
@ -379,7 +379,7 @@ void PackLinuxElf32::pack3(OutputFile *fo, Filter &ft)
}
// Compute new offset of &DT_INIT.d_val.
if (/*0==jni_onload_sym &&*/ phdr->PT_DYNAMIC==type) {
off_init = rel + ioff;
off_init = so_slide + ioff;
fi->seek(ioff, SEEK_SET);
fi->read(ibuf, len);
Elf32_Dyn *dyn = (Elf32_Dyn *)(void *)ibuf;
@ -395,7 +395,7 @@ void PackLinuxElf32::pack3(OutputFile *fo, Filter &ft)
// fall through to relocate .p_offset
}
if (xct_off < ioff)
set_te32(&phdr->p_offset, rel + ioff);
set_te32(&phdr->p_offset, so_slide + ioff);
}
if (off_init) { // change DT_INIT.d_val
fo->seek(off_init, SEEK_SET);
@ -546,7 +546,7 @@ void PackLinuxElf::defineSymbols(Filter const *)
}
PackLinuxElf32::PackLinuxElf32(InputFile *f)
: super(f), phdri(NULL), note_body(NULL), shdri(NULL),
: super(f), phdri(NULL) , shdri(NULL), note_body(NULL),
page_mask(~0u<<lg2_page),
dynseg(NULL), hashtab(NULL), gashtab(NULL), dynsym(NULL),
jni_onload_sym(NULL),
@ -566,7 +566,7 @@ PackLinuxElf32::~PackLinuxElf32()
}
PackLinuxElf64::PackLinuxElf64(InputFile *f)
: super(f), phdri(NULL), note_body(NULL), shdri(NULL),
: super(f), phdri(NULL), shdri(NULL), note_body(NULL),
page_mask(~0ull<<lg2_page),
dynseg(NULL), hashtab(NULL), gashtab(NULL), dynsym(NULL),
jni_onload_sym(NULL),
@ -3521,8 +3521,62 @@ void PackLinuxElf32::pack4(OutputFile *fo, Filter &ft)
//elfout.phdr[0].p_flags |= Elf32_Phdr::PF_W;
}
fo->seek(0, SEEK_SET);
if (0!=xct_off) { // shared library
if (opt->o_unix.android_shlib && shdri) { // dlopen() checks Elf32_Shdr vs Elf32_Phdr
unsigned load0_hi = ~0;
Elf32_Phdr const *phdr = phdri;
for (unsigned j = 0; j < e_phnum; ++j, ++phdr) {
unsigned load0_lo = get_te32(&phdr->p_vaddr);
unsigned load0_sz = get_te32(&phdr->p_memsz);
if (PT_LOAD32==get_te32(&phdr->p_type)
&& (xct_off - load0_lo) < load0_sz) {
load0_hi = load0_lo + load0_sz;
break;
}
}
MemBuffer smap(e_shnum); smap.clear(); // smap[0] = 0; // SHN_UNDEF
MemBuffer snew(e_shnum * sizeof(*shdri));
Elf32_Shdr const *shdr = shdri;
unsigned k = 0;
for (unsigned j = 0; j < e_shnum; ++j, ++shdr) {
// Select some Elf32_Shdr by .sh_type
unsigned const type = get_te32(&shdr->sh_type);
unsigned const flags = get_te32(&shdr->sh_flags);
if (((Elf32_Shdr::SHT_STRTAB == type) && (Elf32_Shdr::SHF_ALLOC & flags))
|| ((Elf32_Shdr::SHT_DYNAMIC == type) && (Elf32_Shdr::SHF_ALLOC & flags))
|| ( ((1+ Elf32_Shdr::SHT_LOOS) <= type) // SHT_ANDROID_REL
&& ((2+ Elf32_Shdr::SHT_LOOS) >= type)) // SHT_ANDROID_RELA
) {
Elf32_Shdr *const sptr = k + (Elf32_Shdr *)(void *)snew;
unsigned va = get_te32(&shdr->sh_addr);
if (xct_off <= va && va <= load0_hi) {
throwCantPack("Android-required Shdr in packed region");
}
*sptr = *shdr; // copy old Elf32_Shdr
smap[j] = 1+ k++; // for later forwarding
}
}
if (k && fo) {
set_te32(&ehdri.e_shoff, fpad4(fo));
set_te16(&ehdri.e_shentsize, sizeof(*shdri));
set_te16(&ehdri.e_shnum, 1+ k);
Elf32_Shdr shdr_undef; memset(&shdr_undef, 0, sizeof(shdr_undef));
fo->write(&shdr_undef, sizeof(shdr_undef));
for (unsigned j = 0; j < k; ++j) { // forward .sh_link
Elf32_Shdr *const sptr = j + (Elf32_Shdr *)(void *)snew;
unsigned sh_offset = get_te32(&sptr->sh_offset);
if (xct_off <= sh_offset) {
set_te32(&sptr->sh_offset, so_slide + sh_offset);
}
sptr->sh_name = 0; // we flushed .e_shstrndx
set_te16(&sptr->sh_link, smap[sptr->sh_link]);
set_te16(&sptr->sh_info, smap[sptr->sh_info]); // ?
}
fo->write(snew, k * sizeof(*shdri));
}
}
fo->seek(0, SEEK_SET);
fo->rewrite(&ehdri, sizeof(ehdri));
fo->rewrite(phdri, e_phnum * sizeof(*phdri));
fo->seek(sz_elf_hdrs, SEEK_SET);
@ -3534,7 +3588,6 @@ void PackLinuxElf32::pack4(OutputFile *fo, Filter &ft)
set_te32(&tmp, tmp);
fo->seek(ptr_udiff(&jni_onload_sym->st_value, file_image), SEEK_SET);
fo->rewrite(&tmp, sizeof(tmp));
fo->seek(0, SEEK_SET);
}
}
else {
@ -3549,6 +3602,7 @@ void PackLinuxElf32::pack4(OutputFile *fo, Filter &ft)
reloc + get_te32(&phdr->p_paddr));
}
}
fo->seek(0, SEEK_SET);
fo->rewrite(&elfout, sizeof(Elf32_Phdr) * o_phnum + sizeof(Elf32_Ehdr));
fo->seek(sz_elf_hdrs, SEEK_SET); // skip over PT_NOTE bodies, if any
fo->rewrite(&linfo, sizeof(linfo));

5
src/p_lx_elf.h
View File

@ -152,11 +152,12 @@ protected:
protected:
Elf32_Ehdr ehdri; // from input file
Elf32_Phdr *phdri; // for input file
Elf32_Shdr const *shdri; // from input file
unsigned e_phoff;
unsigned e_shoff;
unsigned so_slide;
unsigned char *note_body; // concatenated contents of PT_NOTEs, if any
unsigned note_size; // total size of PT_NOTEs
Elf32_Shdr const *shdri; // from input file
unsigned page_mask; // AND clears the offset-within-page
Elf32_Dyn const *dynseg; // from PT_DYNAMIC
@ -270,11 +271,11 @@ protected:
protected:
Elf64_Ehdr ehdri; // from input file
Elf64_Phdr *phdri; // for input file
Elf64_Shdr const *shdri; // from input file
upx_uint64_t e_phoff;
upx_uint64_t e_shoff;
unsigned char *note_body; // concatenated contents of PT_NOTEs, if any
unsigned note_size; // total size of PT_NOTEs
Elf64_Shdr const *shdri; // from input file
upx_uint64_t page_mask; // AND clears the offset-within-page
Elf64_Dyn const *dynseg; // from PT_DYNAMIC