From 75e4daaf29f10d2b31be4991507bfa0673b4e9e4 Mon Sep 17 00:00:00 2001
From: Breno Rodrigues Guimaraes <brenorg@gmail.com>
Date: Fri, 17 Mar 2023 17:55:32 -0300
Subject: Add infrastructure to iterate on all objects that are string indexes

---
 src/patchelf.cc | 40 ++++++++++++++++++++++++++++++++++++++--
 src/patchelf.h  | 38 ++++++++++++++++++++++++++++++++++++--
 2 files changed, 74 insertions(+), 4 deletions(-)

diff --git a/src/patchelf.cc b/src/patchelf.cc
index 37e6479..f2f9043 100644
--- a/src/patchelf.cc
+++ b/src/patchelf.cc
@@ -2293,6 +2293,42 @@ void ElfFile<ElfFileParamNames>::modifyExecstack(ExecstackMode op)
     printf("execstack: %c\n", result);
 }
 
+template<ElfFileParams>
+template<class StrIdxCallback>
+void ElfFile<ElfFileParamNames>::forAllStringReferences(Elf_Shdr& strTabHdr, StrIdxCallback&& fn)
+{
+    for (auto& sym : tryGetSectionSpan<Elf_Sym>(".dynsym"))
+        fn(sym.st_name);
+
+    for (auto& dyn : tryGetSectionSpan<Elf_Dyn>(".dynamic"))
+        switch (rdi(dyn.d_tag))
+        {
+            case DT_NEEDED:
+            case DT_SONAME:
+            case DT_RPATH:
+            case DT_RUNPATH: fn(dyn.d_un.d_val);
+            default:;
+        }
+
+    if (auto verdHdr = tryFindSectionHeader(".gnu.version_d"))
+    {
+        if (&shdrs.at(rdi(verdHdr->get().sh_link)) == &strTabHdr)
+            forAll_ElfVer(getSectionSpan<Elf_Verdef>(*verdHdr),
+                [] (auto& /*vd*/) {},
+                [&] (auto& vda) { fn(vda.vda_name); }
+            );
+    }
+
+    if (auto vernHdr = tryFindSectionHeader(".gnu.version_r"))
+    {
+        if (&shdrs.at(rdi(vernHdr->get().sh_link)) == &strTabHdr)
+            forAll_ElfVer(getSectionSpan<Elf_Verneed>(*vernHdr),
+                [&] (auto& vn) { fn(vn.vn_file); },
+                [&] (auto& vna) { fn(vna.vna_name); }
+            );
+    }
+}
+
 static bool printInterpreter = false;
 static bool printOsAbi = false;
 static bool setOsAbi = false;
@@ -2397,9 +2433,9 @@ static void patchElf()
         const std::string & outputFileName2 = outputFileName.empty() ? fileName : outputFileName;
 
         if (getElfType(fileContents).is32Bit)
-            patchElf2(ElfFile<Elf32_Ehdr, Elf32_Phdr, Elf32_Shdr, Elf32_Addr, Elf32_Off, Elf32_Dyn, Elf32_Sym, Elf32_Verneed, Elf32_Versym, Elf32_Rel, Elf32_Rela, 32>(fileContents), fileContents, outputFileName2);
+            patchElf2(ElfFile<Elf32_Ehdr, Elf32_Phdr, Elf32_Shdr, Elf32_Addr, Elf32_Off, Elf32_Dyn, Elf32_Sym, Elf32_Versym, Elf32_Verdef, Elf32_Verdaux, Elf32_Verneed, Elf32_Vernaux, Elf32_Rel, Elf32_Rela, 32>(fileContents), fileContents, outputFileName2);
         else
-            patchElf2(ElfFile<Elf64_Ehdr, Elf64_Phdr, Elf64_Shdr, Elf64_Addr, Elf64_Off, Elf64_Dyn, Elf64_Sym, Elf64_Verneed, Elf64_Versym, Elf64_Rel, Elf64_Rela, 64>(fileContents), fileContents, outputFileName2);
+            patchElf2(ElfFile<Elf64_Ehdr, Elf64_Phdr, Elf64_Shdr, Elf64_Addr, Elf64_Off, Elf64_Dyn, Elf64_Sym, Elf64_Versym, Elf64_Verdef, Elf64_Verdaux, Elf64_Verneed, Elf64_Vernaux, Elf64_Rel, Elf64_Rela, 64>(fileContents), fileContents, outputFileName2);
     }
 }
 
diff --git a/src/patchelf.h b/src/patchelf.h
index 9fab18c..4e229d6 100644
--- a/src/patchelf.h
+++ b/src/patchelf.h
@@ -10,8 +10,8 @@
 
 using FileContents = std::shared_ptr<std::vector<unsigned char>>;
 
-#define ElfFileParams class Elf_Ehdr, class Elf_Phdr, class Elf_Shdr, class Elf_Addr, class Elf_Off, class Elf_Dyn, class Elf_Sym, class Elf_Verneed, class Elf_Versym, class Elf_Rel, class Elf_Rela, unsigned ElfClass
-#define ElfFileParamNames Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Addr, Elf_Off, Elf_Dyn, Elf_Sym, Elf_Verneed, Elf_Versym, Elf_Rel, Elf_Rela, ElfClass
+#define ElfFileParams class Elf_Ehdr, class Elf_Phdr, class Elf_Shdr, class Elf_Addr, class Elf_Off, class Elf_Dyn, class Elf_Sym, class Elf_Versym, class Elf_Verdef, class Elf_Verdaux, class Elf_Verneed, class Elf_Vernaux, class Elf_Rel, class Elf_Rela, unsigned ElfClass
+#define ElfFileParamNames Elf_Ehdr, Elf_Phdr, Elf_Shdr, Elf_Addr, Elf_Off, Elf_Dyn, Elf_Sym, Elf_Versym, Elf_Verdef, Elf_Verdaux, Elf_Verneed, Elf_Vernaux, Elf_Rel, Elf_Rela, ElfClass
 
 template<class T>
 struct span
@@ -237,6 +237,40 @@ private:
         }
     }
 
+    template<class StrIdxCallback>
+    void forAllStringReferences(const Elf_Shdr& strTabHdr, StrIdxCallback&& fn);
+
+    template<class T, class U>
+    auto follow(U* ptr, size_t offset) -> T* {
+        return offset ? (T*)(((char*)ptr)+offset) : nullptr;
+    };
+
+    template<class VdFn, class VaFn>
+    void forAll_ElfVer(span<Elf_Verdef> vdspan, VdFn&& vdfn, VaFn&& vafn)
+    {
+        auto* vd = vdspan.begin();
+        for (; vd; vd = follow<Elf_Verdef>(vd, rdi(vd->vd_next)))
+        {
+            vdfn(*vd);
+            auto va = follow<Elf_Verdaux>(vd, rdi(vd->vd_aux));
+            for (; va; va = follow<Elf_Verdaux>(va, rdi(va->vda_next)))
+                vafn(*va);
+        }
+    }
+
+    template<class VnFn, class VaFn>
+    void forAll_ElfVer(span<Elf_Verneed> vnspan, VnFn&& vnfn, VaFn&& vafn)
+    {
+        auto* vn = vnspan.begin();
+        for (; vn; vn = follow<Elf_Verneed>(vn, rdi(vn->vn_next)))
+        {
+            vnfn(*vn);
+            auto va = follow<Elf_Vernaux>(vn, rdi(vn->vn_aux));
+            for (; va; va = follow<Elf_Vernaux>(va, rdi(va->vna_next)))
+                vafn(*va);
+        }
+    }
+
     /* Convert an integer in big or little endian representation (as
        specified by the ELF header) to this platform's integer
        representation. */
-- 
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