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ELF shared library: PT_NOTE can prevent packing

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Android build environment post-processing is adding a PT_NOTE
("Android", 21, "r16-beta1") at the high end of PT_LOAD[0],
above the stub; the runtime linker looks there before de-compression.
https://github.com/upx/upx/issues/124
	modified:   p_lx_elf.cpp
This commit is contained in:
John Reiser 2017-11-20 10:08:24 -08:00
parent 6eafa552bb
commit b413f3da26
1 changed files with 24 additions and 3 deletions
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27
src/p_lx_elf.cpp
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@ -1774,6 +1774,17 @@ bool PackLinuxElf32::canPack()
throwCantPack("DT_ tag above stub");
goto abandon;
}
phdr = phdri;
for (unsigned j= 0; j < e_phnum; ++phdr, ++j) {
unsigned const vaddr = get_te32(&phdr->p_vaddr);
if (Elf32_Phdr::PT_NOTE == get_te32(&phdr->p_type)
&& xct_va < vaddr) {
char buf[40]; snprintf(buf, sizeof(buf),
"PT_NOTE %#x above stub", vaddr);
throwCantPack(buf);
goto abandon;
}
}
xct_off = elf_get_offset_from_address(xct_va);
if (opt->debug.debug_level) {
fprintf(stderr, "shlib canPack: xct_va=%#lx xct_off=%lx\n",
@ -1879,9 +1890,8 @@ PackLinuxElf64::canPack()
if (sec_dynsym)
sec_dynstr = get_te64(&sec_dynsym->sh_link) + shdri;
int j= e_phnum;
phdr= phdri;
for (; --j>=0; ++phdr)
for (int j= e_phnum; --j>=0; ++phdr)
if (Elf64_Phdr::PT_DYNAMIC==get_te32(&phdr->p_type)) {
dynseg= (Elf64_Dyn const *)(get_te64(&phdr->p_offset) + file_image);
break;
@ -1918,7 +1928,7 @@ PackLinuxElf64::canPack()
}
Elf64_Shdr const *shdr = shdri;
xct_va = ~0ull;
for (j= e_shnum; --j>=0; ++shdr) {
for (int j= e_shnum; --j>=0; ++shdr) {
if (Elf64_Shdr::SHF_EXECINSTR & get_te32(&shdr->sh_flags)) {
xct_va = umin64(xct_va, get_te64(&shdr->sh_addr));
}
@ -1938,6 +1948,17 @@ PackLinuxElf64::canPack()
throwCantPack("DT_ tag above stub");
goto abandon;
}
phdr = phdri;
for (unsigned j= 0; j < e_phnum; ++phdr, ++j) {
upx_uint64_t const vaddr = get_te64(&phdr->p_vaddr);
if (Elf64_Phdr::PT_NOTE == get_te32(&phdr->p_type)
&& xct_va < vaddr) {
char buf[40]; snprintf(buf, sizeof(buf),
"PT_NOTE %#lx above stub", (unsigned long)vaddr);
throwCantPack(buf);
goto abandon;
}
}
xct_off = elf_get_offset_from_address(xct_va);
if (opt->debug.debug_level) {
fprintf(stderr, "shlib canPack: xct_va=%#lx xct_off=%lx\n",