diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/patchelf.cc | 123 |
1 files changed, 119 insertions, 4 deletions
diff --git a/src/patchelf.cc b/src/patchelf.cc index cb5fef3..6359a04 100644 --- a/src/patchelf.cc +++ b/src/patchelf.cc @@ -144,6 +144,10 @@ public: string getInterpreter(); + string getSoname(); + + void setSoname(const string & newSoname); + void setInterpreter(const string & newInterpreter); typedef enum { rpPrint, rpShrink, rpSet } RPathOp; @@ -839,12 +843,21 @@ void ElfFile<ElfFileParamNames>::rewriteHeaders(Elf_Addr phdrAddress) debug("rewriting symbol table section %d\n", i); for (size_t entry = 0; (entry + 1) * sizeof(Elf_Sym) <= rdi(shdrs[i].sh_size); entry++) { Elf_Sym * sym = (Elf_Sym *) (contents + rdi(shdrs[i].sh_offset) + entry * sizeof(Elf_Sym)); - if (sym->st_shndx != SHN_UNDEF && sym->st_shndx < SHN_LORESERVE) { - string section = sectionsByOldIndex[rdi(sym->st_shndx)]; + unsigned int shndx = rdi(sym->st_shndx); + if (shndx != SHN_UNDEF && shndx < SHN_LORESERVE) { + if (shndx >= sectionsByOldIndex.size()) { + fprintf(stderr, "warning: entry %d in symbol table refers to a non-existent section, skipping\n", shndx); + continue; + } + string section = sectionsByOldIndex.at(shndx); assert(!section.empty()); unsigned int newIndex = findSection3(section); // inefficient - //debug("rewriting symbol %d: index = %d (%s) -> %d\n", entry, rdi(sym->st_shndx), section.c_str(), newIndex); + //debug("rewriting symbol %d: index = %d (%s) -> %d\n", entry, shndx, section.c_str(), newIndex); wri(sym->st_shndx, newIndex); + /* Rewrite st_value. FIXME: we should do this for all + types, but most don't actually change. */ + if (ELF32_ST_TYPE(rdi(sym->st_info)) == STT_SECTION) + wri(sym->st_value, rdi(shdrs[newIndex].sh_addr)); } } } @@ -866,6 +879,89 @@ string ElfFile<ElfFileParamNames>::getInterpreter() return string((char *) contents + rdi(shdr.sh_offset), rdi(shdr.sh_size)); } +template<ElfFileParams> +string ElfFile<ElfFileParamNames>::getSoname() +{ + Elf_Shdr & shdrDynamic = findSection(".dynamic"); + Elf_Shdr & shdrDynStr = findSection(".dynstr"); + char * strTab = (char *) contents + rdi(shdrDynStr.sh_offset); + + /* Find the DT_STRTAB entry in the dynamic section. */ + Elf_Dyn * dyn = (Elf_Dyn *) (contents + rdi(shdrDynamic.sh_offset)); + Elf_Addr strTabAddr = 0; + for ( ; rdi(dyn->d_tag) != DT_NULL; dyn++) + if (rdi(dyn->d_tag) == DT_STRTAB) strTabAddr = rdi(dyn->d_un.d_ptr); + if (!strTabAddr) error("strange: no string table"); + + /* We assume that the virtual address in the DT_STRTAB entry + of the dynamic section corresponds to the .dynstr section. */ + assert(strTabAddr == rdi(shdrDynStr.sh_addr)); + + Elf_Dyn * dynSoname = (Elf_Dyn *) (contents + rdi(shdrDynamic.sh_offset)); + char * soname = 0; + for ( ; rdi(dynSoname->d_tag) != DT_NULL; dynSoname++) { + if (rdi(dynSoname->d_tag) == DT_SONAME) { + soname = strTab + rdi(dynSoname->d_un.d_val); + break; + } + } + if (rdi(dynSoname->d_tag) == DT_NULL) { + error("Specified ELF file does not contain any DT_SONAME entry in .dynamic section!"); + } + else { + return soname; + } +} + +template<ElfFileParams> +void ElfFile<ElfFileParamNames>::setSoname(const string & newSoname) +{ + Elf_Shdr & shdrDynamic = findSection(".dynamic"); + Elf_Shdr & shdrDynStr = findSection(".dynstr"); + char * strTab = (char *) contents + rdi(shdrDynStr.sh_offset); + + /* Find the DT_STRTAB entry in the dynamic section. */ + Elf_Dyn * dyn = (Elf_Dyn *) (contents + rdi(shdrDynamic.sh_offset)); + Elf_Addr strTabAddr = 0; + for ( ; rdi(dyn->d_tag) != DT_NULL; dyn++) + if (rdi(dyn->d_tag) == DT_STRTAB) strTabAddr = rdi(dyn->d_un.d_ptr); + if (!strTabAddr) error("strange: no string table"); + + /* We assume that the virtual address in the DT_STRTAB entry + of the dynamic section corresponds to the .dynstr section. */ + assert(strTabAddr == rdi(shdrDynStr.sh_addr)); + + Elf_Dyn * dynSoname = (Elf_Dyn *) (contents + rdi(shdrDynamic.sh_offset)); + char * soname = 0; + for ( ; rdi(dynSoname->d_tag) != DT_NULL; dynSoname++) { + if (rdi(dynSoname->d_tag) == DT_SONAME) { + soname = strTab + rdi(dynSoname->d_un.d_val); + break; + } + } + if (rdi(dynSoname->d_tag) == DT_NULL) + error("Specified ELF file does not contain any DT_SONAME entry in .dynamic section!"); + + if (newSoname.size() <= strlen(soname)) { + debug("old soname: `%s', new soname: `%s'\n", soname, newSoname.c_str()); + strcpy(soname, newSoname.c_str()); + changed = true; + } + else { + /* Grow the .dynstr section to make room for the new DT_SONAME */ + debug("new soname is too long, resizing .dynstr section...\n"); + + string & newDynStr = replaceSection(".dynstr", + rdi(shdrDynStr.sh_size) + newSoname.size() + 1); + setSubstr(newDynStr, rdi(shdrDynStr.sh_size), newSoname + '\0'); + /* Update the DT_SONAME entry, if any */ + if (dynSoname) { + debug("old soname: `%s', new soname: `%s'\n", soname, newSoname.c_str()); + dynSoname->d_un.d_val = shdrDynStr.sh_size; + changed = true; + } + } +} template<ElfFileParams> void ElfFile<ElfFileParamNames>::setInterpreter(const string & newInterpreter) @@ -1177,6 +1273,9 @@ void ElfFile<ElfFileParamNames>::addNeeded(set<string> libs) static bool printInterpreter = false; +static bool printSoname = false; +static bool setSoname = false; +static string newSoname; static string newInterpreter; static bool shrinkRPath = false; @@ -1195,6 +1294,12 @@ static void patchElf2(ElfFile & elfFile, mode_t fileMode) if (printInterpreter) printf("%s\n", elfFile.getInterpreter().c_str()); + if (printSoname) + printf("%s\n", elfFile.getSoname().c_str()); + + if (setSoname) + elfFile.setSoname(newSoname); + if (newInterpreter != "") elfFile.setInterpreter(newInterpreter); @@ -1219,7 +1324,7 @@ static void patchElf2(ElfFile & elfFile, mode_t fileMode) static void patchElf() { - if (!printInterpreter && !printRPath) + if (!printInterpreter && !printRPath && !printSoname) debug("patching ELF file `%s'\n", fileName.c_str()); mode_t fileMode; @@ -1256,6 +1361,8 @@ void showHelp(const string & progName) fprintf(stderr, "syntax: %s\n\ [--set-interpreter FILENAME]\n\ [--print-interpreter]\n\ + [--print-soname]\t\tPrints 'DT_SONAME' entry of .dynamic section. Raises an error if DT_SONAME doesn't exist\n\ + [--set-soname SONAME]\t\tSets 'DT_SONAME' entry to SONAME. Raises an error if DT_SONAME doesn't exist\n\ [--set-rpath RPATH]\n\ [--shrink-rpath]\n\ [--print-rpath]\n\ @@ -1288,6 +1395,14 @@ int main(int argc, char * * argv) else if (arg == "--print-interpreter") { printInterpreter = true; } + else if (arg == "--print-soname") { + printSoname = true; + } + else if (arg == "--set-soname") { + if (++i == argc) error("missing argument"); + setSoname = true; + newSoname = argv[i]; + } else if (arg == "--shrink-rpath") { shrinkRPath = true; } |