mirror of https://github.com/upx/upx.git
ImportLinker copied into PeFile
This commit is contained in:
László Molnár
parent
8ab229cca9
commit
96708d7592
260
src/pefile.cpp
260
src/pefile.cpp
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@ -31,6 +31,7 @@
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#include "filter.h"
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#include "packer.h"
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#include "pefile.h"
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#include "linker.h"
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#define FILLVAL 0
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@ -120,6 +121,7 @@ PeFile::PeFile(InputFile *f) : super(f)
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soxrelocs = 0;
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sotls = 0;
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isdll = false;
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ilinker = NULL;
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}
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@ -458,6 +460,257 @@ void PeFile32::processRelocs() // pass1
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info("Relocations: original size: %u bytes, preprocessed size: %u bytes",(unsigned) IDSIZE(PEDIR_RELOC),sorelocs);
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}
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/*************************************************************************
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// import handling
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**************************************************************************/
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__packed_struct(import_desc)
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LE32 oft; // orig first thunk
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char _[8];
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LE32 dllname;
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LE32 iat; // import address table
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__packed_struct_end()
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/*
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ImportLinker: 32 and 64 bit import table building.
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Import entries (dll name + proc name/ordinal pairs) can be
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added in arbitrary order.
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Internally it works by creating sections with special names,
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and adding relocation entries between those sections. The special
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names ensure that when the import table is built in the memory
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from those sections, a correct table can be generated simply by
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sorting the sections by name, and adding all of them to the output
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in the sorted order.
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*/
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class PeFile::ImportLinker : public ElfLinkerAMD64
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{
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struct tstr : private ::noncopyable
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{
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char *s;
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explicit tstr(char *str) : s(str) {}
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~tstr() { delete [] s; }
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operator char *() const { return s; }
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};
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// encoding of dll and proc names are required, so that our special
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// control characters in the name of sections can work as intended
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static char *encode_name(const char *name, char *buf)
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{
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char *b = buf;
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while (*name)
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{
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*b++ = 'a' + ((*name >> 4) & 0xf);
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*b++ = 'a' + (*name & 0xf);
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name++;
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}
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*b = 0;
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return buf;
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}
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static char *name_for_dll(const char *dll, char first_char)
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{
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assert(dll);
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unsigned l = strlen(dll);
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assert(l > 0);
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char *name = new char[3 * l + 2];
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assert(name);
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name[0] = first_char;
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char *n = name + 1 + 2 * l;
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do {
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*n++ = tolower(*dll);
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} while(*dll++);
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return encode_name(name + 1 + 2 * l, name + 1) - 1;
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}
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static char *name_for_proc(const char *dll, const char *proc,
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char first_char, char separator)
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{
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unsigned len = 1 + 2 * strlen(dll) + 1 + 2 * strlen(proc) + 1 + 1;
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tstr dlln(name_for_dll(dll, first_char));
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char *procn = new char[len];
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snprintf(procn, len - 1, "%s%c", (const char*) dlln, separator);
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encode_name(proc, procn + strlen(procn));
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return procn;
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}
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static char zeros[sizeof(import_desc)];
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enum {
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// the order of identifiers is very important below!!
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descriptor_id = 'D',
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thunk_id,
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dll_name_id,
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proc_name_id,
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ordinal_id,
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thunk_separator_first,
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thunk_separator,
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thunk_separator_last,
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procname_separator,
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};
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unsigned thunk_size; // 4 or 8 bytes
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void add(const char *dll, const char *proc, unsigned ordinal)
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{
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tstr sdll(name_for_dll(dll, dll_name_id));
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tstr desc_name(name_for_dll(dll, descriptor_id));
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char tsep = thunk_separator;
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if (findSection(sdll, false) == NULL)
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{
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tsep = thunk_separator_first;
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addSection(sdll, dll, strlen(dll) + 1, 0); // name of the dll
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addSymbol(sdll, sdll, 0);
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addSection(desc_name, zeros, sizeof(zeros), 0); // descriptor
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addRelocation(desc_name, offsetof(import_desc, dllname),
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"R_X86_64_32", sdll, 0);
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}
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tstr thunk(name_for_proc(dll, proc, thunk_id, tsep));
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addSection(thunk, zeros, thunk_size, 0);
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addSymbol(thunk, thunk, 0);
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if (tsep == thunk_separator_first)
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{
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addRelocation(desc_name, offsetof(import_desc, iat),
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"R_X86_64_32", thunk, 0);
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tstr last_thunk(name_for_proc(dll, "X", thunk_id, thunk_separator_last));
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addSection(last_thunk, zeros, thunk_size, 0);
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}
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const char *reltype = thunk_size == 4 ? "R_X86_64_32" : "R_X86_64_64";
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if (ordinal != 0u)
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{
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addRelocation(thunk, 0, reltype, "*UND*",
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ordinal | (1ull << (thunk_size * 8 - 1)));
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}
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else
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{
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tstr proc_name(name_for_proc(dll, proc, proc_name_id, procname_separator));
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addSection(proc_name, zeros, 2, 1); // 2 bytes of word aligned "hint"
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addSymbol(proc_name, proc_name, 0);
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addRelocation(thunk, 0, reltype, proc_name, 0);
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strcat(proc_name, "X");
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addSection(proc_name, proc, strlen(proc), 0); // the name of the symbol
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}
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}
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static int __acc_cdecl_qsort compare(const void *p1, const void *p2)
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{
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const Section *s1 = * (const Section * const *) p1;
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const Section *s2 = * (const Section * const *) p2;
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return strcmp(s1->name, s2->name);
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}
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virtual void alignCode(unsigned len) { alignWithByte(len, 0); }
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const Section *getThunk(const char *dll, const char *proc, char tsep) const
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{
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assert(dll);
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assert(proc);
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tstr thunk(name_for_proc(dll, proc, thunk_id, tsep));
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return findSection(thunk, false);
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}
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public:
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explicit ImportLinker(unsigned thunk_size_) : thunk_size(thunk_size_)
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{
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assert(thunk_size == 4 || thunk_size == 8);
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addSection("*UND*", NULL, 0, 0);
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addSymbol("*UND*", "*UND*", 0);
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addSection("*ZSTART", NULL, 0, 0);
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addSymbol("*ZSTART", "*ZSTART", 0);
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Section *s = addSection("Dzero", zeros, sizeof(import_desc), 0);
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assert(s->name[0] == descriptor_id);
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// one trailing 00 byte after the last proc name
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addSection("Zzero", zeros, 1, 0);
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}
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template <typename C>
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void add(const C *dll, unsigned ordinal)
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{
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assert(ordinal > 0 && ordinal < 0x10000);
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char ord[20];
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snprintf(ord, sizeof(ord), "%c%05u", ordinal_id, ordinal);
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add((const char*) dll, ord, ordinal);
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}
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template <typename C1, typename C2>
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void add(const C1 *dll, const C2 *proc)
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{
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assert(proc);
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add((const char*) dll, (const char*) proc, 0);
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}
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unsigned build()
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{
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assert(output == NULL);
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int osize = 4 + 2 * nsections; // upper limit for alignments
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for (unsigned ic = 0; ic < nsections; ic++)
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osize += sections[ic]->size;
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output = new upx_byte[osize];
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// sort the sections by name before adding them all
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qsort(sections, nsections, sizeof (Section*), ImportLinker::compare);
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for (unsigned ic = 0; ic < nsections; ic++)
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addLoader(sections[ic]->name);
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addLoader("+40D");
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assert(outputlen <= osize);
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//OutputFile::dump("il0.imp", output, outputlen);
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return outputlen;
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}
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void relocate(unsigned myimport)
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{
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assert(nsections > 0);
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assert(output);
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defineSymbol("*ZSTART", /*0xffffffffff1000ull + 0 * */ myimport);
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ElfLinkerAMD64::relocate();
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//OutputFile::dump("il1.imp", output, outputlen);
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}
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template <typename C1, typename C2>
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upx_uint64_t getAddress(const C1 *dll, const C2 *proc) const
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{
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const Section *s = getThunk((const char*) dll, (const char*) proc,
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thunk_separator_first);
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if (s == NULL && (s = getThunk((const char*) dll,(const char*) proc,
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thunk_separator)) == NULL)
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throwInternalError("entry not found");
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return s->offset;
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}
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template <typename C1>
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upx_uint64_t getAddress(const C1 *dll, unsigned ordinal) const
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{
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assert(ordinal > 0 && ordinal < 0x10000);
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char ord[20];
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snprintf(ord, sizeof(ord), "%c%05u", ordinal_id, ordinal);
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const Section *s = getThunk((const char*) dll, ord, thunk_separator_first);
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if (s == NULL
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&& (s = getThunk((const char*) dll, ord, thunk_separator)) == NULL)
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throwInternalError("entry not found");
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return s->offset;
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}
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template <typename C1>
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upx_uint64_t getAddress(const C1 *dll) const
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{
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tstr sdll(name_for_dll((const char*) dll, dll_name_id));
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return findSection(sdll, true)->offset;
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}
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};
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char PeFile::ImportLinker::zeros[sizeof(import_desc)];
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#if 0
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/*************************************************************************
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// import handling
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@ -1804,6 +2057,13 @@ PeFile32::PeFile32(InputFile *f) : super(f)
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iddirs = ih.ddirs;
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oddirs = oh.ddirs;
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ilinker = new ImportLinker(4);
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}
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PeFile32::~PeFile32()
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{
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delete ilinker;
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}
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void PeFile32::readPeHeader()
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@ -42,6 +42,7 @@ protected:
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class Reloc;
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class Resource;
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class Export;
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class ImportLinker;
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PeFile(InputFile *f);
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virtual ~PeFile();
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@ -68,6 +69,7 @@ protected:
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unsigned soimport;
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upx_byte *oimpdlls;
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unsigned soimpdlls;
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ImportLinker *ilinker;
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virtual void processRelocs() = 0;
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void processRelocs(Reloc *);
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@ -347,7 +349,7 @@ class PeFile32 : public PeFile
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typedef PeFile super;
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protected:
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PeFile32(InputFile *f);
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//virtual ~PeFile32();
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virtual ~PeFile32();
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virtual void unpack(OutputFile *fo);
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virtual void readPeHeader();
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