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remove raw pointer from findSection2 #323

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Merged
merged 2 commits into from
Oct 26, 2021
Merged

remove raw pointer from findSection2 #323

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a1352e5
remove raw pointer from findSection2
Mic92 Sep 19, 2021
4c73989
use more memory-safe at() function
Mic92 Sep 19, 2021
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2 changes: 1 addition & 1 deletion src/Makefile.am
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
AM_CXXFLAGS = -Wall -std=c++11 -D_FILE_OFFSET_BITS=64
AM_CXXFLAGS = -Wall -std=c++17 -D_FILE_OFFSET_BITS=64

if WITH_ASAN
AM_CXXFLAGS += -fsanitize=address -fsanitize-address-use-after-scope
Expand Down
37 changes: 20 additions & 17 deletions src/patchelf.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -160,7 +160,7 @@ class ElfFile

Elf_Shdr & findSection(const SectionName & sectionName);

Elf_Shdr * findSection2(const SectionName & sectionName);
std::optional<std::reference_wrapper<Elf_Shdr>> findSection2(const SectionName & sectionName);

unsigned int findSection3(const SectionName & sectionName);

Expand Down Expand Up @@ -600,7 +600,7 @@ void ElfFile<ElfFileParamNames>::shiftFile(unsigned int extraPages, Elf_Addr sta
PT_INTERP segment into memory. Otherwise glibc will choke. */
phdrs.resize(rdi(hdr()->e_phnum) + 1);
wri(hdr()->e_phnum, rdi(hdr()->e_phnum) + 1);
Elf_Phdr & phdr = phdrs[rdi(hdr()->e_phnum) - 1];
Elf_Phdr & phdr = phdrs.at(rdi(hdr()->e_phnum) - 1);
wri(phdr.p_type, PT_LOAD);
wri(phdr.p_offset, 0);
wri(phdr.p_vaddr, wri(phdr.p_paddr, startPage));
Expand Down Expand Up @@ -637,10 +637,12 @@ Elf_Shdr & ElfFile<ElfFileParamNames>::findSection(const SectionName & sectionNa


template<ElfFileParams>
Elf_Shdr * ElfFile<ElfFileParamNames>::findSection2(const SectionName & sectionName)
std::optional<std::reference_wrapper<Elf_Shdr>> ElfFile<ElfFileParamNames>::findSection2(const SectionName & sectionName)
{
auto i = findSection3(sectionName);
return i ? &shdrs[i] : nullptr;
if (i)
return shdrs.at(i);
return {};
}


Expand Down Expand Up @@ -861,7 +863,7 @@ void ElfFile<ElfFileParamNames>::rewriteSectionsLibrary()
wri(hdr()->e_phoff, sizeof(Elf_Ehdr));
phdrs.resize(rdi(hdr()->e_phnum) + 1);
wri(hdr()->e_phnum, rdi(hdr()->e_phnum) + 1);
Elf_Phdr & phdr = phdrs[rdi(hdr()->e_phnum) - 1];
Elf_Phdr & phdr = phdrs.at(rdi(hdr()->e_phnum) - 1);
wri(phdr.p_type, PT_LOAD);
wri(phdr.p_offset, startOffset);
wri(phdr.p_vaddr, wri(phdr.p_paddr, startPage));
Expand Down Expand Up @@ -914,7 +916,7 @@ void ElfFile<ElfFileParamNames>::rewriteSectionsExecutable()
Elf_Addr startAddr = rdi(shdrs.at(lastReplaced + 1).sh_addr);
std::string prevSection;
for (unsigned int i = 1; i <= lastReplaced; ++i) {
Elf_Shdr & shdr(shdrs[i]);
Elf_Shdr & shdr(shdrs.at(i));
std::string sectionName = getSectionName(shdr);
debug("looking at section '%s'\n", sectionName.c_str());
/* !!! Why do we stop after a .dynstr section? I can't
Expand Down Expand Up @@ -955,7 +957,7 @@ void ElfFile<ElfFileParamNames>::rewriteSectionsExecutable()
assert(rdi(hdr()->e_shnum) == shdrs.size());
sortShdrs();
for (unsigned int i = 1; i < rdi(hdr()->e_shnum); ++i)
* ((Elf_Shdr *) (fileContents->data() + rdi(hdr()->e_shoff)) + i) = shdrs[i];
* ((Elf_Shdr *) (fileContents->data() + rdi(hdr()->e_shoff)) + i) = shdrs.at(i);
}


Expand Down Expand Up @@ -1121,7 +1123,7 @@ void ElfFile<ElfFileParamNames>::rewriteHeaders(Elf_Addr phdrAddress)
(e.g., those produced by klibc's klcc). */
auto shdrDynamic = findSection2(".dynamic");
if (shdrDynamic) {
auto dyn_table = (Elf_Dyn *) (fileContents->data() + rdi(shdrDynamic->sh_offset));
auto dyn_table = (Elf_Dyn *) (fileContents->data() + rdi((*shdrDynamic).get().sh_offset));
unsigned int d_tag;
for (auto dyn = dyn_table; (d_tag = rdi(dyn->d_tag)) != DT_NULL; dyn++)
if (d_tag == DT_STRTAB)
Expand All @@ -1136,13 +1138,14 @@ void ElfFile<ElfFileParamNames>::rewriteHeaders(Elf_Addr phdrAddress)
auto shdr = findSection2(".gnu.hash");
// some binaries might this section stripped
// in which case we just ignore the value.
if (shdr) dyn->d_un.d_ptr = shdr->sh_addr;
if (shdr) dyn->d_un.d_ptr = (*shdr).get().sh_addr;
} else if (d_tag == DT_JMPREL) {
auto shdr = findSection2(".rel.plt");
if (!shdr) shdr = findSection2(".rela.plt"); /* 64-bit Linux, x86-64 */
if (!shdr) shdr = findSection2(".rela.plt");
/* 64-bit Linux, x86-64 */
if (!shdr) shdr = findSection2(".rela.IA_64.pltoff"); /* 64-bit Linux, IA-64 */
if (!shdr) error("cannot find section corresponding to DT_JMPREL");
dyn->d_un.d_ptr = shdr->sh_addr;
dyn->d_un.d_ptr = (*shdr).get().sh_addr;
}
else if (d_tag == DT_REL) { /* !!! hack! */
auto shdr = findSection2(".rel.dyn");
Expand All @@ -1152,14 +1155,14 @@ void ElfFile<ElfFileParamNames>::rewriteHeaders(Elf_Addr phdrAddress)
/* some programs have neither section, but this doesn't seem
to be a problem */
if (!shdr) continue;
dyn->d_un.d_ptr = shdr->sh_addr;
dyn->d_un.d_ptr = (*shdr).get().sh_addr;
}
else if (d_tag == DT_RELA) {
auto shdr = findSection2(".rela.dyn");
/* some programs lack this section, but it doesn't seem to
be a problem */
if (!shdr) continue;
dyn->d_un.d_ptr = shdr->sh_addr;
dyn->d_un.d_ptr = (*shdr).get().sh_addr;
}
else if (d_tag == DT_VERNEED)
dyn->d_un.d_ptr = findSection(".gnu.version_r").sh_addr;
Expand All @@ -1172,7 +1175,7 @@ void ElfFile<ElfFileParamNames>::rewriteHeaders(Elf_Addr phdrAddress)
if (shdr) {
auto rld_map_addr = findSection(".rld_map").sh_addr;
auto dyn_offset = ((char*)dyn) - ((char*)dyn_table);
dyn->d_un.d_ptr = rld_map_addr + dyn_offset - shdrDynamic->sh_addr;
dyn->d_un.d_ptr = rld_map_addr + dyn_offset - (*shdrDynamic).get().sh_addr;
} else {
/* ELF file with DT_MIPS_RLD_MAP_REL but without .rld_map
is broken, and it's not our job to fix it; yet, we have
Expand Down Expand Up @@ -1346,12 +1349,12 @@ std::string ElfFile<ElfFileParamNames>::shrinkRPath(char* rpath, std::vector<std
exists in this directory. */
bool libFound = false;
for (unsigned int j = 0; j < neededLibs.size(); ++j)
if (!neededLibFound[j]) {
std::string libName = dirName + "/" + neededLibs[j];
if (!neededLibFound.at(j)) {
std::string libName = dirName + "/" + neededLibs.at(j);
try {
Elf32_Half library_e_machine = getElfType(readFile(libName, sizeof(Elf32_Ehdr))).machine;
if (rdi(library_e_machine) == rdi(hdr()->e_machine)) {
neededLibFound[j] = true;
neededLibFound.at(j) = true;
libFound = true;
} else
debug("ignoring library '%s' because its machine type differs\n", libName.c_str());
Expand Down