mirror/upx
1
0
Fork 0
mirror of https://github.com/upx/upx synced 2025-09-28 19:06:07 +08:00
Code Issues Releases Wiki Activity

src: make sort order deterministic, next try

Browse Source 
We cannot compare pointers as they may point to qsort-local objects.
And we must make sure that cmp(a,b) always agrees with cmp(b,a).
This commit is contained in:
Markus F.X.J. Oberhumer 2023-08-30 16:41:59 +02:00
parent f4e5b29708
commit cfa8107ab9
5 changed files with 54 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
src/linker.cpp
View File

@ -329,6 +329,7 @@ ElfLinker::Section *ElfLinker::addSection(const char *sname, const void *sdata,
assert(sname[strlen(sname) - 1] != ':');
assert(findSection(sname, false) == nullptr);
Section *sec = new Section(sname, sdata, slen, p2align);
sec->sort_id = nsections;
sections[nsections++] = sec;
return sec;
}

1
src/linker.h
View File

@ -119,6 +119,7 @@ struct ElfLinker::Section : private noncopyable {
void *input = nullptr;
byte *output = nullptr;
unsigned size = 0;
unsigned sort_id = 0; // for qsort()
upx_uint64_t offset = 0;
unsigned p2align = 0; // log2
Section *next = nullptr;

19
src/p_mach.cpp
View File

@ -562,7 +562,8 @@ PackMachBase<T>::compare_segment_command(void const *const aa, void const *const
unsigned const xb = b->cmd - lc_seg;
if (xa < xb) return -1; // LC_SEGMENT first
if (xa > xb) return 1;
if (0 != xa) return 0; // not LC_SEGMENT
// mfx @jreiser: we do not want to return 0; please check
//// if (0 != xa) return 0; // not LC_SEGMENT
// Ascending by .fileoff so that find_SEGMENT_gap works
if (a->fileoff < b->fileoff)
return -1;
@ -572,10 +573,24 @@ PackMachBase<T>::compare_segment_command(void const *const aa, void const *const
if (a->vmaddr < b->vmaddr) return -1;
if (a->vmaddr > b->vmaddr) return 1;
// Descending by .vmsize
// mfx @jreiser: I think this may violate cmp(a,b) == -cmp(b,a); please check
// if ((a->vmsize != 0) != (b->vmsize != 0))
// return (a->vmsize != 0) ? -1 : 1;
if (a->vmsize) return -1; // 'a' is first
if (b->vmsize) return 1; // 'a' is last
// What could remain?
return aa < bb ? -1 : 1; // make sort order deterministic/stable
#define CMP(field) \
if (a->field != b->field) return a->field < b->field ? -1 : 1
// try to make sort order deterministic and just compare more fields
CMP(vmsize);
CMP(cmdsize);
CMP(filesize);
CMP(maxprot);
CMP(initprot);
CMP(nsects);
CMP(flags);
#undef CMP
return 0;
}
// At 2013-02-03 part of the source for codesign was

12
src/p_vmlinx.cpp
View File

@ -99,7 +99,17 @@ PackVmlinuxBase<T>::compare_Phdr(void const *aa, void const *bb)
if (a->p_paddr < b->p_paddr) return -1; // ascending by .p_paddr
if (a->p_paddr > b->p_paddr) return 1;
// What could remain?
return aa < bb ? -1 : 1; // make sort order deterministic/stable
// try to make sort order deterministic and just compare more fields
#define CMP(field) \
if (a->field != b->field) return a->field < b->field ? -1 : 1
CMP(p_offset);
CMP(p_vaddr);
CMP(p_filesz);
CMP(p_memsz);
CMP(p_flags);
CMP(p_align);
#undef CMP
return 0;
}
template <class T>

45
src/pefile.cpp
View File

@ -697,14 +697,15 @@ class PeFile::ImportLinker final : public ElfLinkerAMD64 {
infoWarning("empty import: %s", dll);
}
static int __acc_cdecl_qsort compare(const void *p1, const void *p2) {
const Section *s1 = *(const Section *const *) p1;
const Section *s2 = *(const Section *const *) p2;
int rc = strcmp(s1->name, s2->name);
static int __acc_cdecl_qsort compare(const void *aa, const void *bb) {
const Section *a = *(const Section *const *) aa;
const Section *b = *(const Section *const *) bb;
int rc = strcmp(a->name, b->name);
if (rc != 0)
return rc;
// What could remain?
return p1 < p2 ? -1 : 1; // make sort order deterministic/stable
assert_noexcept(a->sort_id != b->sort_id);
return a->sort_id < b->sort_id ? -1 : 1; // make sort order deterministic
}
virtual void alignCode(unsigned len) override { alignWithByte(len, 0); }
@ -873,29 +874,31 @@ unsigned PeFile::processImports0(ord_mask_t ord_mask) // pass 1
unsigned original_position;
bool isk32;
static int __acc_cdecl_qsort compare(const void *p1, const void *p2) {
const udll *u1 = *(const udll *const *) p1;
const udll *u2 = *(const udll *const *) p2;
if (u1->isk32 != u2->isk32)
return u1->isk32 ? -1 : 1;
if ((*u1->lookupt != 0) != (*u2->lookupt != 0))
return (*u1->lookupt != 0) ? -1 : 1;
int rc = strcasecmp(u1->name, u2->name);
static int __acc_cdecl_qsort compare(const void *aa, const void *bb) {
const udll *a = *(const udll *const *) aa;
const udll *b = *(const udll *const *) bb;
if (a->isk32 != b->isk32)
return a->isk32 ? -1 : 1;
if ((*a->lookupt != 0) != (*b->lookupt != 0))
return (*a->lookupt != 0) ? -1 : 1;
int rc = strcasecmp(a->name, b->name);
if (rc != 0)
return rc;
if ((u1->ordinal != 0) != (u2->ordinal != 0))
return (u1->ordinal != 0) ? -1 : 1;
if (u1->shname && u2->shname) {
rc = (int) (upx_safe_strlen(u1->shname) - upx_safe_strlen(u2->shname));
if ((a->ordinal != 0) != (b->ordinal != 0))
return (a->ordinal != 0) ? -1 : 1;
if (a->shname && b->shname) {
rc = (int) (upx_safe_strlen(a->shname) - upx_safe_strlen(b->shname));
if (rc != 0)
return rc;
rc = strcmp(u1->shname, u2->shname);
rc = strcmp(a->shname, b->shname);
if (rc != 0)
return rc;
} else if ((u1->shname != nullptr) != (u2->shname != nullptr))
return (u1->shname != nullptr) ? -1 : 1;
} else if ((a->shname != nullptr) != (b->shname != nullptr))
return (a->shname != nullptr) ? -1 : 1;
// What could remain?
return p1 < p2 ? -1 : 1; // make sort order deterministic/stable
// make sort order deterministic
assert_noexcept(a->original_position != b->original_position);
return a->original_position < b->original_position ? -1 : 1;
}
};