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Cleanup PackLinuxElf64amd::defineSymbols(): use is_pie; reduce symbols

Browse Source 
modified:   p_lx_elf.cpp
	modified:   stub/src/amd64-linux.elf-entry.S
	modified:   stub/src/amd64-linux.elf-fold.S

	modified:   stub/amd64-linux.elf-entry.h
	modified:   stub/amd64-linux.elf-fold.h
	modified:   stub/tmp/amd64-linux.elf-entry.bin.dump
	modified:   stub/tmp/amd64-linux.elf-fold.map
This commit is contained in:
John Reiser
2017-04-06 17:22:30 -07:00
parent e88d2ff88c
commit 85fdd579d6
7 changed files with 256 additions and 296 deletions
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src/p_lx_elf.cpp
+12 -40
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@@ -1060,8 +1060,6 @@ PackLinuxElf64amd::defineSymbols(Filter const *ft)
{
PackLinuxElf64::defineSymbols(ft);
unsigned const hlen = sz_elf_hdrs + sizeof(l_info) + sizeof(p_info);
// We want to know if compressed data, plus stub, plus a couple pages,
// will fit below the uncompressed program in memory. But we don't
// know the final total compressed size yet, so use the uncompressed
@@ -1079,15 +1077,13 @@ PackLinuxElf64amd::defineSymbols(Filter const *ft)
}
lsize = /*getLoaderSize()*/ 64 * 1024; // XXX: upper bound; avoid circularity
upx_uint64_t lo_va_stub = get_te64(&elfout.phdr[0].p_vaddr);
upx_uint64_t adrc;
upx_uint64_t adrm;
upx_uint64_t adru;
upx_uint64_t adrx;
unsigned cntc;
unsigned lenm;
unsigned lenu;
len += (7&-lsize) + lsize;
is_big = (lo_va_user < (lo_va_stub + len + 2*page_size));
upx_uint64_t my_page_size = 4096u;
upx_uint64_t my_page_mask = -my_page_size;
is_big = (lo_va_user < (lo_va_stub + len + 2 * my_page_size));
if (is_pie || (is_big /*&& ehdri.ET_EXEC==get_te16(&ehdri.e_type)*/)) {
// .e_entry is set later by PackLinuxElf64::updateLoader
set_te64( &elfout.ehdr.e_entry,
@@ -1095,44 +1091,20 @@ PackLinuxElf64amd::defineSymbols(Filter const *ft)
set_te64(&elfout.phdr[0].p_vaddr, lo_va_user);
set_te64(&elfout.phdr[0].p_paddr, lo_va_user);
lo_va_stub = lo_va_user;
adrc = lo_va_stub;
adrm = getbrk(phdri, e_phnum);
adru = page_mask & (~page_mask + adrm); // round up to page boundary
adrx = adru + hlen;
lenm = page_size + len;
lenu = page_size + len;
cntc = len >> 3; // over-estimate; corrected at runtime
adrm = getbrk(phdri, e_phnum) - lo_va_user;
lenm = my_page_size + len;
lenu = my_page_size + len;
}
else {
adrm = lo_va_stub + len;
adrc = adrm;
adru = lo_va_stub;
adrx = lo_va_stub + hlen;
lenm = page_size;
lenu = page_size + len;
cntc = 0;
adrm = len;
lenm = my_page_size;
lenu = my_page_size + len;
}
adrm = page_mask & (~page_mask + adrm); // round up to page boundary
adrc = page_mask & (~page_mask + adrc); // round up to page boundary
//linker->defineSymbol("ADRX", adrx); // compressed input for eXpansion
ACC_UNUSED(adrx);
// For actual moving, we need the true count, which depends on sz_pack2
// and is not yet known. So the runtime stub detects "no move"
// if adrm==adrc, and otherwise uses actual sz_pack2 to compute cntc.
//linker->defineSymbol("CNTC", cntc); // count for copy
ACC_UNUSED(cntc);
adrm = my_page_mask & (~my_page_mask + adrm); // round up to page boundary
linker->defineSymbol("LENU", lenu); // len for unmap
//linker->defineSymbol("ADRC", adrc); // addr for copy
//linker->defineSymbol("ADRU", adru); // addr for unmap
ACC_UNUSED(adru);
#define EI_NIDENT 16 /* <elf.h> */
linker->defineSymbol("JMPU", EI_NIDENT -4 + lo_va_user); // unmap trampoline
#undef EI_NIDENT
linker->defineSymbol("LENM", lenm); // len for map
linker->defineSymbol("ADRM", adrm); // addr for map
linker->defineSymbol("ADRM", adrm); // offset from &Elf64_Ehdr
//linker->dumpSymbols(); // debug
}
@@ -3769,7 +3741,7 @@ void PackLinuxElf64::pack4(OutputFile *fo, Filter &ft)
if (Elf64_Ehdr::ET_DYN==get_te16(&ehdri.e_type)) {
upx_uint64_t const base= get_te64(&elfout.phdr[0].p_vaddr);
set_te16(&elfout.ehdr.e_type, Elf64_Ehdr::ET_DYN);
set_te16(&elfout.ehdr.e_phnum, 1);
//set_te16(&elfout.ehdr.e_phnum, 1);
set_te64( &elfout.ehdr.e_entry,
get_te64(&elfout.ehdr.e_entry) - base);
set_te64(&elfout.phdr[0].p_vaddr, get_te64(&elfout.phdr[0].p_vaddr) - base);