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WIP: clarify compressWithFilters; reduce size of obuf for PackLinuxElf64

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modified:   p_lx_elf.cpp
	modified:   packer.cpp
	modified:   packer.h
This commit is contained in:
John Reiser
2022-03-21 13:49:46 -07:00
committed by Markus F.X.J. Oberhumer
parent 0e2a9de2b2
commit 663d6b466b
3 changed files with 92 additions and 44 deletions
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src/p_lx_elf.cpp
+37 -20
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@@ -2276,8 +2276,8 @@ bool PackLinuxElf32::canPack()
if (r_va == user_init_ava) { // found the Elf32_Rel
unsigned r_info = get_te32(&rp->r_info);
unsigned r_type = ELF32_R_TYPE(r_info);
if (Elf32_Ehdr::EM_ARM == e_machine
&& R_ARM_RELATIVE == r_type) {
if ((Elf32_Ehdr::EM_ARM == e_machine && R_ARM_RELATIVE == r_type)
|| (Elf32_Ehdr::EM_386 == e_machine && R_386_RELATIVE == r_type) ) {
user_init_va = get_te32(&file_image[user_init_off]);
}
else {
@@ -2464,7 +2464,7 @@ PackLinuxElf64::canPack()
return false;
}
// The first PT_LOAD64 must cover the beginning of the file (0==p_offset).
upx_uint64_t max_LOADsz = 0, max_offset = 0;
Elf64_Phdr const *phdr = phdri;
for (unsigned j=0; j < e_phnum; ++phdr, ++j) {
if (j >= 14) {
@@ -2472,23 +2472,27 @@ PackLinuxElf64::canPack()
return false;
}
unsigned const p_type = get_te32(&phdr->p_type);
if (1!=exetype && PT_LOAD64 == p_type) { // 1st PT_LOAD
exetype = 1;
load_va = get_te64(&phdr->p_vaddr); // class data member
upx_uint64_t const p_offset = get_te64(&phdr->p_offset);
upx_uint64_t const off = ~page_mask & load_va;
if (off && off == p_offset) { // specific hint
throwCantPack("Go-language PT_LOAD: try hemfix.c, or try '--force-execve'");
// Fixing it inside upx fails because packExtent() reads original file.
return false;
if (PT_LOAD64 == p_type) {
// The first PT_LOAD64 must cover the beginning of the file (0==p_offset).
if (1!= exetype) {
exetype = 1;
load_va = get_te64(&phdr->p_vaddr); // class data member
upx_uint64_t const p_offset = get_te64(&phdr->p_offset);
upx_uint64_t const off = ~page_mask & load_va;
if (off && off == p_offset) { // specific hint
throwCantPack("Go-language PT_LOAD: try hemfix.c, or try '--force-execve'");
// Fixing it inside upx fails because packExtent() reads original file.
return false;
}
if (0 != p_offset) { // 1st PT_LOAD must cover Ehdr and Phdr
throwCantPack("first PT_LOAD.p_offset != 0; try '--force-execve'");
return false;
}
// FIXME: bad for shlib!
hatch_off = ~3ul & (3+ get_te64(&phdr->p_memsz));
}
if (0 != p_offset) { // 1st PT_LOAD must cover Ehdr and Phdr
throwCantPack("first PT_LOAD.p_offset != 0; try '--force-execve'");
return false;
}
// FIXME: bad for shlib!
hatch_off = ~3ul & (3+ get_te64(&phdr->p_memsz));
break;
max_LOADsz = UPX_MAX(max_LOADsz, get_te64(&phdr->p_filesz));
max_offset = UPX_MAX(max_offset, get_te64(&phdr->p_filesz) + get_te64(&phdr->p_offset));
}
}
// We want to compress position-independent executable (gcc -pie)
@@ -2804,7 +2808,8 @@ proceed: ;
exetype = 0;
// set options
opt->o_unix.blocksize = blocksize = file_size;
// .blocksize: avoid over-allocating
opt->o_unix.blocksize = blocksize = UPX_MAX(max_LOADsz, file_size - max_offset);
return true;
}
@@ -3689,6 +3694,18 @@ void PackLinuxElf64::pack1(OutputFile *fo, Filter & /*ft*/)
assert(e_phoff == sizeof(Elf64_Ehdr)); // checked by canPack()
sz_phdrs = e_phnum * get_te16(&ehdri.e_phentsize);
// We compress separate pieces (usually each PT_LOAD, plus the gaps in the file
// that are not covered by any PT_LOAD), but currently at run time there can be
// only one decompressor method.
// Therefore we must plan ahead because Packer::compressWithFilters tries
// to find the smallest result among the available methods.
// In the future we may allow more than one decompression method at run time,
// but for now we must choose just one, and force compressWithFilters to use it.
int methods[256];
int nmethods = prepareMethods(methods, ph.method, getCompressionMethods(M_ALL, ph.level));
if (1 < nmethods) {
}
Elf64_Phdr *phdr = phdri;
note_size = 0;
for (unsigned j=0; j < e_phnum; ++phdr, ++j) {