Add flag to zero progbits sections

Author: brenoguim

patchelf.1

@@ -129,6 +129,13 @@ Set the output file name.  If not specified, the input will be modified in place
 .IP --debug
 Prints details of the changes made to the input file.
 
+.IP --zero-progbits
+Clears all SHT_PROGBITS sections.
+
+This can be helpful to generate binaries that can be shared and added to regression
+tests.
+It will strip most of the sensitive content and dangerous content.
+
 .IP --version
 Shows the version of patchelf.
 

src/patchelf.cc

@@ -1878,6 +1878,18 @@ void ElfFile<ElfFileParamNames>::noDefaultLib()
     changed = true;
 }
 
+template<ElfFileParams>
+void ElfFile<ElfFileParamNames>::zeroProgbits()
+{
+    for (auto& shdr : shdrs)
+        if (rdi(shdr.sh_type) == SHT_PROGBITS)
+            memset(fileContents->data() + rdi(shdr.sh_offset), 0,
+                   rdi(shdr.sh_size));
+
+    this->rewriteSections();
+    changed = true;
+}
+
 template<ElfFileParams>
 void ElfFile<ElfFileParamNames>::addDebugTag()
 {
@@ -2040,6 +2052,7 @@ static std::set<std::string> neededLibsToAdd;
 static std::set<std::string> symbolsToClearVersion;
 static bool printNeeded = false;
 static bool noDefaultLib = false;
+static bool zeroProgbits = false;
 static bool printExecstack = false;
 static bool clearExecstack = false;
 static bool setExecstack = false;
@@ -2097,6 +2110,9 @@ static void patchElf2(ElfFile && elfFile, const FileContents & fileContents, con
     if (addDebugTag)
         elfFile.addDebugTag();
 
+    if (zeroProgbits)
+        elfFile.zeroProgbits();
+
     if (elfFile.isChanged()){
         writeFile(fileName, elfFile.fileContents);
     } else if (alwaysWrite) {
@@ -2162,6 +2178,7 @@ static void showHelp(const std::string & progName)
   [--set-execstack]\n\
   [--output FILE]\n\
   [--debug]\n\
+  [--zero-progbits]\t\tClear all progbits sections. Helpful to share tests with sensitive content\n\
   [--version]\n\
   FILENAME...\n", progName.c_str());
 }
@@ -2285,6 +2302,9 @@ static int mainWrapped(int argc, char * * argv)
         else if (arg == "--debug") {
             debugMode = true;
         }
+        else if (arg == "--zero-progbits") {
+            zeroProgbits = true;
+        }
         else if (arg == "--no-default-lib") {
             noDefaultLib = true;
         }

src/patchelf.h

@@ -149,6 +149,8 @@ class ElfFile
 
     void modifyExecstack(ExecstackMode op);
 
+    void zeroProgbits();
+
 private:
 
     /* Convert an integer in big or little endian representation (as