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Extend LOAD segments by the size of the new section #470

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Extend LOAD segments by the size of the new section #470

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21 changes: 17 additions & 4 deletions src/patchelf.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -922,10 +922,7 @@ void ElfFile<ElfFileParamNames>::rewriteSectionsExecutable()
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
remember! */
if ((rdi(shdr.sh_type) == SHT_PROGBITS && sectionName != ".interp")
|| prevSection == ".dynstr")
if (rdi(shdr.sh_type) == SHT_PROGBITS && sectionName != ".interp")
{
startOffset = rdi(shdr.sh_offset);
startAddr = rdi(shdr.sh_addr);
Expand Down Expand Up @@ -994,6 +991,22 @@ void ElfFile<ElfFileParamNames>::rewriteSectionsExecutable()

firstPage -= neededPages * getPageSize();
startOffset += neededPages * getPageSize();
} else {
// Calculate how many bytes are needed out of the additional pages.
Elf_Off curOff = sizeof(Elf_Ehdr) + phdrs.size() * sizeof(Elf_Phdr);
size_t extraSpace = neededSpace - curOff;

/* Find segment mapping the rewritten sections and increase its size
Also make it RW (not great) */
for (auto& segment : phdrs)
if (rdi(segment.p_type) == PT_LOAD &&
rdi(segment.p_offset) <= curOff &&
rdi(segment.p_offset) + rdi(segment.p_filesz) >= curOff)
{
wri(segment.p_filesz, rdi(segment.p_filesz) + extraSpace);
wri(segment.p_memsz, rdi(segment.p_memsz) + extraSpace);
wri(segment.p_flags, PF_R | PF_W);
}
}


Expand Down