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Change class PackLinuxI386elf : public PackLinuxI386

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into   class PackLinuxElf32x86 : public PackLinuxElf32Le : public PackLinuxElf32
which makes the code for compressing ELF (for direct-to-memory decompression)
cleaner because ELF has some of the class tree to itself.
This assumes PROT_EXEC|PROT_WRITE ought to work.
This is checked at runtime, and if it fails then
give a message on stderr and exit(127).

Modify --force-execve so that runtime avoids PROT_EXEC|PROT_WRITE.
Then executables compressed with --force-execve will run under
PaX, grSecurity, and strict SELinux.
This commit is contained in:
John Reiser
2006-05-21 13:58:24 -07:00
parent 69a00c0ab3
commit d2718e99a4
26 changed files with 1049 additions and 969 deletions
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src/p_lx_exc.cpp
+14 -97
View File
@@ -134,11 +134,6 @@ PackLinuxI386::generateElfHdr(
memset(&h1->linfo, 0, sizeof(h1->linfo));
fo->write(h1, sizeof(*h1));
}
else if (ph.format==UPX_F_LINUX_ELF_i386) {
assert(h2->ehdr.e_phnum==2);
memset(&h2->linfo, 0, sizeof(h2->linfo));
fo->write(h2, sizeof(*h2));
}
else if (ph.format==UPX_F_LINUX_SH_i386) {
assert(h2->ehdr.e_phnum==1);
h2->ehdr.e_phnum = 1;
@@ -228,11 +223,19 @@ PackLinuxI386::pack4(OutputFile *fo, Filter &ft)
fo->write(shstrtab, sizeof(shstrtab));
#endif // }
// 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.
#if 0 /*{*/
#undef PAGE_MASK
#define PAGE_MASK (~0u<<12)
// pre-calculate for benefit of runtime disappearing act via munmap()
elfout.phdr[0].p_memsz = PAGE_MASK & (~PAGE_MASK + elfout.phdr[0].p_filesz);
#undef PAGE_MASK
#else /*}{*/
elfout.phdr[0].p_memsz = elfout.phdr[0].p_filesz;
#endif /*}*/
// rewrite Elf header
fo->seek(0, SEEK_SET);
@@ -276,19 +279,14 @@ PackLinuxI386::buildLinuxLoader(
}
unsigned char const *const uncLoader = fold_hdrlen + fold;
unsigned char *const cprLoader = new unsigned char[sizeof(h) + h.sz_unc];
unsigned char *const cprLoader = new unsigned char[h.sz_unc];
if (0 < szfold) {
unsigned sz_cpr;
int r = upx_compress(uncLoader, h.sz_unc, sizeof(h) + cprLoader, &sz_cpr,
NULL, ph.method, 10, NULL, NULL );
unsigned sz_cpr = h.sz_unc;
memcpy(cprLoader, uncLoader, sz_cpr);
h.sz_cpr = sz_cpr;
if (r != UPX_E_OK || h.sz_cpr >= h.sz_unc)
throwInternalError("loader compression failed");
}
memcpy(cprLoader, &h, sizeof(h));
// This adds the definition to the "library", to be used later.
linker->addSection("FOLDEXEC", cprLoader, sizeof(h) + h.sz_cpr);
linker->addSection("FOLDEXEC", cprLoader, h.sz_cpr);
delete [] cprLoader;
n_mru = ft->n_mru;
@@ -311,28 +309,6 @@ PackLinuxI386::buildLinuxLoader(
addLoader("LEXEC000", NULL);
if (ft->id) {
if (ph.format==UPX_F_LINUX_ELF_i386) { // decompr, unfilter are separate
addLoader("LXUNF000", NULL);
addLoader("LXUNF002", NULL);
if (0x80==(ft->id & 0xF0)) {
if (256==n_mru) {
addLoader("MRUBYTE0", NULL);
}
else if (n_mru) {
addLoader("LXMRU005", NULL);
}
if (n_mru) {
addLoader("LXMRU006", NULL);
}
else {
addLoader("LXMRU007", NULL);
}
}
else if (0x40==(ft->id & 0xF0)) {
addLoader("LXUNF008", NULL);
}
addLoader("LXUNF010", NULL);
}
if (n_mru) {
addLoader("LEXEC009", NULL);
}
@@ -341,12 +317,7 @@ PackLinuxI386::buildLinuxLoader(
addLoader(getDecompressor(), NULL);
addLoader("LEXEC015", NULL);
if (ft->id) {
if (ph.format==UPX_F_LINUX_ELF_i386) { // decompr, unfilter are separate
if (0x80!=(ft->id & 0xF0)) {
addLoader("LXUNF042", NULL);
}
}
else { // decompr, unfilter not separate
{ // decompr, unfilter not separate
if (0x80==(ft->id & 0xF0)) {
addLoader("LEXEC110", NULL);
if (n_mru) {
@@ -357,15 +328,7 @@ PackLinuxI386::buildLinuxLoader(
}
}
addFilter32(ft->id);
if (ph.format==UPX_F_LINUX_ELF_i386) { // decompr, unfilter are separate
if (0x80==(ft->id & 0xF0)) {
if (0==n_mru) {
addLoader("LXMRU058", NULL);
}
}
addLoader("LXUNF035", NULL);
}
else { // decompr always unfilters
{ // decompr always unfilters
addLoader("LEXEC017", NULL);
}
}
@@ -404,24 +367,6 @@ PackLinuxI386::buildLoader(Filter const *ft)
patch_le32(buf,sz_fold,"UPX3",progid);
patch_le32(buf,sz_fold,"UPX2",exetype > 0 ? 0 : 0x7fffffff);
// get fresh filter
Filter fold_ft = *ft;
fold_ft.init(ft->id, ft->addvalue);
int preferred_ctos[2] = {ft->cto, -1};
fold_ft.preferred_ctos = preferred_ctos;
// filter
optimizeFilter(&fold_ft, buf, sz_fold);
unsigned fold_hdrlen = sizeof(l_info) + sizeof(Elf32_Ehdr) +
sizeof(Elf32_Phdr) * get_native32(&((Elf32_Ehdr const *)(void *)buf)->e_phnum);
if (0 == get_le32(fold_hdrlen + buf)) {
// inconsistent SIZEOF_HEADERS in *.lds (ld, binutils)
fold_hdrlen = umax(0x80, fold_hdrlen);
}
bool success = fold_ft.filter(buf + fold_hdrlen, sz_fold - fold_hdrlen);
(void)success;
return buildLinuxLoader(
linux_i386exec_loader, sizeof(linux_i386exec_loader),
buf, sz_fold, ft );
@@ -479,34 +424,6 @@ int PackLinuxI386::checkEhdr(const Elf32_Ehdr *ehdr) const
}
off_t PackLinuxI386::getbrk(const Elf32_Phdr *phdr, int e_phnum) const
{
off_t brka = 0;
for (int j = 0; j < e_phnum; ++phdr, ++j) {
if (phdr->PT_LOAD == phdr->p_type) {
off_t b = phdr->p_vaddr + phdr->p_memsz;
if (b > brka)
brka = b;
}
}
return brka;
}
off_t PackLinuxI386::getbase(const Elf32_Phdr *phdr, int e_phnum) const
{
off_t base = ~0u;
for (int j = 0; j < e_phnum; ++phdr, ++j) {
if (phdr->PT_LOAD == phdr->p_type) {
if (phdr->p_vaddr < (unsigned) base)
base = phdr->p_vaddr;
}
}
if (0!=base) {
return base;
}
return 0x12000;
}
/*************************************************************************
//