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

Option --preserve-build-id for Gnu ELF; contributed by Nicholas Twerdochlib

Browse Source 
(SourceForge [ upx-Patches-3413335 ])
This commit is contained in:
John Reiser
2011-12-13 17:26:03 -08:00
parent 57e9b27085
commit 640d5b2dec
5 changed files with 222 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/p_lx_elf.cpp
+196 -5
View File
@@ -51,6 +51,12 @@
static unsigned const EF_ARM_EABI_VER4 = 0x04000000;
static unsigned const EF_ARM_EABI_VER5 = 0x05000000;
unsigned char PackLinuxElf::o_shstrtab[] = { \
/*start*/ '\0',
/*offset 1*/ '.','n','o','t','e','.','g','n','u','.','b','u','i','l','d','-','i','d','\0',
/*offset 20*/ '.','s','h','s','t','r','t','a','b','\0'
};
static unsigned
umin(unsigned a, unsigned b)
{
@@ -180,7 +186,8 @@ PackLinuxElf::PackLinuxElf(InputFile *f)
: super(f), e_phnum(0), file_image(NULL), dynstr(NULL),
sz_phdrs(0), sz_elf_hdrs(0), sz_pack2(0), sz_pack2a(0), sz_pack2b(0),
lg2_page(12), page_size(1u<<lg2_page), xct_off(0), xct_va(0),
e_machine(0), ei_class(0), ei_data(0), ei_osabi(0), osabi_note(NULL)
e_machine(0), ei_class(0), ei_data(0), ei_osabi(0), osabi_note(NULL),
o_elf_shnum(0)
{
}
@@ -1141,6 +1148,21 @@ Elf32_Shdr const *PackLinuxElf32::elf_find_section_name(
return 0;
}
Elf64_Shdr const *PackLinuxElf64::elf_find_section_name(
char const *const name
) const
{
Elf64_Shdr const *shdr = shdri;
int j = n_elf_shnum;
for (; 0 <=--j; ++shdr) {
unsigned ndx = get_te64(&shdr->sh_name);
if (0==strcmp(name, &shstrtab[ndx])) {
return shdr;
}
}
return 0;
}
Elf32_Shdr const *PackLinuxElf32::elf_find_section_type(
unsigned const type
) const
@@ -1652,8 +1674,14 @@ PackLinuxElf32::generateElfHdr(
assert(get_te16(&h2->ehdr.e_ehsize) == sizeof(Elf32_Ehdr));
assert(get_te16(&h2->ehdr.e_phentsize) == sizeof(Elf32_Phdr));
set_te16(&h2->ehdr.e_shentsize, sizeof(Elf32_Shdr));
h2->ehdr.e_shnum = 0;
h2->ehdr.e_shstrndx = 0;
if (o_elf_shnum) {
h2->ehdr.e_shnum = o_elf_shnum;
h2->ehdr.e_shstrndx = o_elf_shnum - 1;
}
else {
h2->ehdr.e_shnum = 0;
h2->ehdr.e_shstrndx = 0;
}
sz_elf_hdrs = sizeof(*h2) - sizeof(linfo); // default
set_te32(&h2->phdr[0].p_filesz, sizeof(*h2)); // + identsize;
@@ -1878,8 +1906,14 @@ PackLinuxElf64::generateElfHdr(
assert(get_te16(&h2->ehdr.e_ehsize) == sizeof(Elf64_Ehdr));
assert(get_te16(&h2->ehdr.e_phentsize) == sizeof(Elf64_Phdr));
set_te16(&h2->ehdr.e_shentsize, sizeof(Elf64_Shdr));
h2->ehdr.e_shnum = 0;
h2->ehdr.e_shstrndx = 0;
if (o_elf_shnum) {
h2->ehdr.e_shnum = o_elf_shnum;
h2->ehdr.e_shstrndx = o_elf_shnum - 1;
}
else {
h2->ehdr.e_shnum = 0;
h2->ehdr.e_shstrndx = 0;
}
sz_elf_hdrs = sizeof(*h2) - sizeof(linfo); // default
set_te64(&h2->phdr[0].p_filesz, sizeof(*h2)); // + identsize;
@@ -1965,6 +1999,65 @@ void PackLinuxElf32::pack1(OutputFile *fo, Filter & /*ft*/)
memset(&linfo, 0, sizeof(linfo));
fo->write(&linfo, sizeof(linfo));
}
// if the preserve build-id option was specified
if (opt->o_unix.preserve_build_id) {
n_elf_shnum = ehdri.e_shnum;
Elf32_Shdr *shdr = NULL;
Elf32_Shdr const *tmp = shdri;
if (! shdri) {
shdr = new Elf32_Shdr[n_elf_shnum];
fi->seek(0,SEEK_SET);
fi->seek(ehdri.e_shoff,SEEK_SET);
fi->readx((void*)shdr,ehdri.e_shentsize*ehdri.e_shnum);
// set this so we can use elf_find_section_name
shdri = (Elf32_Shdr * const)shdr;
}
//set the shstrtab
sec_strndx = &shdr[ehdri.e_shstrndx];
char *strtab = new char[sec_strndx->sh_size];
fi->seek(0,SEEK_SET);
fi->seek(sec_strndx->sh_offset,SEEK_SET);
fi->readx(strtab,sec_strndx->sh_size);
shstrtab = (const char*)strtab;
Elf32_Shdr const *buildid = elf_find_section_name(".note.gnu.build-id");
if (buildid) {
unsigned char *data = new unsigned char[buildid->sh_size];
memset(data,0,buildid->sh_size);
fi->seek(0,SEEK_SET);
fi->seek(buildid->sh_offset,SEEK_SET);
fi->readx(data,buildid->sh_size);
buildid_data = data;
o_elf_shnum = 3;
memset(&shdrout.shdr,0,sizeof(shdrout));
//setup the build-id
memcpy(&shdrout.shdr[1],buildid, sizeof(shdrout.shdr[1]));
shdrout.shdr[1].sh_name = 1;
//setup the shstrtab
memcpy(&shdrout.shdr[2],sec_strndx, sizeof(shdrout.shdr[2]));
shdrout.shdr[2].sh_name = 20;
shdrout.shdr[2].sh_size = 29; //size of our static shstrtab
}
// repoint shdr in case it is used by code some where else
if (shdr) {
shdri = tmp;
delete [] shdr;
shdr = NULL;
}
}
}
void PackLinuxElf32x86::pack1(OutputFile *fo, Filter &ft)
@@ -2094,6 +2187,68 @@ void PackLinuxElf64::pack1(OutputFile *fo, Filter & /*ft*/)
memset(&linfo, 0, sizeof(linfo));
fo->write(&linfo, sizeof(linfo));
}
// only execute if option present
if (opt->o_unix.preserve_build_id) {
// set this so we can use elf_find_section_name
n_elf_shnum = ehdri.e_shnum;
// there is a class member similar to this, but I did not
// want to assume it would be available
Elf64_Shdr const *tmp = shdri;
Elf64_Shdr *shdr = NULL;
if (! shdri) {
shdr = new Elf64_Shdr[n_elf_shnum];
fi->seek(0,SEEK_SET);
fi->seek(ehdri.e_shoff,SEEK_SET);
fi->readx((void*)shdr,ehdri.e_shentsize*ehdri.e_shnum);
// set this so we can use elf_find_section_name
shdri = (Elf64_Shdr * const)shdr;
}
//set the shstrtab
sec_strndx = &shdri[ehdri.e_shstrndx];
char *strtab = new char[sec_strndx->sh_size];
fi->seek(0,SEEK_SET);
fi->seek(sec_strndx->sh_offset,SEEK_SET);
fi->readx(strtab,sec_strndx->sh_size);
shstrtab = (const char*)strtab;
Elf64_Shdr const *buildid = elf_find_section_name(".note.gnu.build-id");
if (buildid) {
unsigned char *data = new unsigned char[buildid->sh_size];
memset(data,0,buildid->sh_size);
fi->seek(0,SEEK_SET);
fi->seek(buildid->sh_offset,SEEK_SET);
fi->readx(data,buildid->sh_size);
buildid_data = data;
o_elf_shnum = 3;
memset(&shdrout.shdr,0,sizeof(shdrout));
//setup the build-id
memcpy(&shdrout.shdr[1],buildid, sizeof(shdrout.shdr[1]));
shdrout.shdr[1].sh_name = 1;
//setup the shstrtab
memcpy(&shdrout.shdr[2],sec_strndx, sizeof(shdrout.shdr[2]));
shdrout.shdr[2].sh_name = 20;
shdrout.shdr[2].sh_size = 29; //size of our static shstrtab
}
if (shdr) {
shdri = tmp;
delete [] shdr;
shdr = NULL;
}
}
}
void PackLinuxElf64amd::pack1(OutputFile *fo, Filter &ft)
@@ -2601,6 +2756,24 @@ void PackLinuxElf32::pack4(OutputFile *fo, Filter &ft)
{
overlay_offset = sz_elf_hdrs + sizeof(linfo);
if (opt->o_unix.preserve_build_id) {
// calc e_shoff here and write shdrout, then o_shstrtab
//NOTE: these are pushed last to ensure nothing is stepped on
//for the UPX structure.
unsigned const len = fpad4(fo);
set_te32(&elfout.ehdr.e_shoff,len);
int const ssize = sizeof(shdrout);
shdrout.shdr[2].sh_offset = len+ssize;
shdrout.shdr[1].sh_offset = shdrout.shdr[2].sh_offset+shdrout.shdr[2].sh_size;
fo->write(&shdrout, ssize);
fo->write(o_shstrtab,shdrout.shdr[2].sh_size);
fo->write(buildid_data,shdrout.shdr[1].sh_size);
}
// Cannot pre-round .p_memsz. If .p_filesz < .p_memsz, then kernel
// tries to make .bss, which requires PF_W.
// But strict SELinux (or PaX, grSecurity) disallows PF_W with PF_X.
@@ -2650,6 +2823,24 @@ void PackLinuxElf64::pack4(OutputFile *fo, Filter &ft)
{
overlay_offset = sz_elf_hdrs + sizeof(linfo);
if (opt->o_unix.preserve_build_id) {
// calc e_shoff here and write shdrout, then o_shstrtab
//NOTE: these are pushed last to ensure nothing is stepped on
//for the UPX structure.
unsigned const len = fpad4(fo);
set_te64(&elfout.ehdr.e_shoff,len);
int const ssize = sizeof(shdrout);
shdrout.shdr[2].sh_offset = len+ssize;
shdrout.shdr[1].sh_offset = shdrout.shdr[2].sh_offset+shdrout.shdr[2].sh_size;
fo->write(&shdrout, ssize);
fo->write(o_shstrtab,shdrout.shdr[2].sh_size);
fo->write(buildid_data,shdrout.shdr[1].sh_size);
}
// Cannot pre-round .p_memsz. If .p_filesz < .p_memsz, then kernel
// tries to make .bss, which requires PF_W.
// But strict SELinux (or PaX, grSecurity) disallows PF_W with PF_X.