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wrapgen: Fix address resolution in dynamic section #1355

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Merged
facekapow merged 1 commit into from
May 1, 2023
Merged

wrapgen: Fix address resolution in dynamic section #1355

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23 changes: 21 additions & 2 deletions src/libelfloader/wrapgen/wrapgen.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@
void parse_elf(const char* elf, std::string& soname_out, std::set<std::string>& functions_out, std::set<std::string>& vars_out);
void generate_wrapper(std::ofstream& output, const char* soname, const std::set<std::string>& symbols);
void generate_var_wrappers(std::ofstream& output, std::ofstream& outputHeader, const std::set<std::string>& vars);
Elf64_Off vaddr_to_offset(const Elf64_Ehdr* ehdr, Elf64_Addr vaddr);

int main(int argc, const char** argv)
{
Expand Down Expand Up @@ -168,10 +169,10 @@ void parse_elf(const char* elf, std::string& soname, std::set<std::string>& symb
switch (dyn->d_tag)
{
case DT_STRTAB:
off_strtab = dyn->d_un.d_val;
off_strtab = vaddr_to_offset(ehdr, dyn->d_un.d_val);
break;
case DT_SONAME:
off_soname = dyn->d_un.d_val;
off_soname = vaddr_to_offset(ehdr, dyn->d_un.d_val);
break;
case DT_NULL:
goto end_dyn;
Expand Down Expand Up @@ -298,3 +299,21 @@ void generate_var_wrappers(std::ofstream& output, std::ofstream& outputHeader, c
"}\n"
"#endif\n\n";
}

Elf64_Off vaddr_to_offset(const Elf64_Ehdr* ehdr, Elf64_Xword vaddr)
{
for (int i = 0; i < ehdr->e_phnum; i++)
{
const Elf64_Phdr* phdr;
Elf64_Addr vstart, vend;

phdr = (const Elf64_Phdr*) (((char*) ehdr) + ehdr->e_phoff + (i * ehdr->e_phentsize));
vstart = phdr->p_vaddr;
vend = phdr->p_vaddr + phdr->p_memsz;
if (vstart <= vaddr && vaddr < vend) {
return phdr->p_offset + vaddr - vstart;
}
}

return 0;
}