[linux] Change the way we load vdso pseudo-module

Summary:
This is basically a revert of D16107 and parts of D10800, which were
trying to get vdso loading working. They did this by implementing a
generic load-an-elf-file from memory approach, which is not correct,
since we cannot assume that an elf file is loaded in memory in full (it
usually isn't, as there's no need to load section headers for example).
This meant that we would read garbage instead of section sizes, and if
that garbage happened to be a large number, we would crash while trying
to allocate a buffer to accomodate the hypothetical section.

Instead of this, I add a bit of custom code to load the vdso to
DynamicLoaderPOSIXDYLD (which already needed to handle the vdso
specially). I determine the size of the memory to read using
Process::GetMemoryRegionInfo, which is information coming from the OS,
and cannot be forged by a malicious/misbehaving application.

Reviewers: eugene, clayborg

Subscribers: lldb-commits, ravitheja, tberghammer, emaste

Differential Revision: https://reviews.llvm.org/D34352

llvm-svn: 305780

1 files changed, 19 insertions, 80 deletions

diff --git a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
index b71d6fa4ebe..e6d3379e53d 100644
--- a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
+++ b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
@@ -707,10 +707,7 @@ size_t ObjectFileELF::GetModuleSpecifications(
           SectionHeaderColl section_headers;
           lldb_private::UUID &uuid = spec.GetUUID();
 
-          using namespace std::placeholders;
-          const SetDataFunction set_data =
-              std::bind(&ObjectFileELF::SetData, std::cref(data), _1, _2, _3);
-          GetSectionHeaderInfo(section_headers, set_data, header, uuid,
+          GetSectionHeaderInfo(section_headers, data, header, uuid,
                                gnu_debuglink_file, gnu_debuglink_crc,
                                spec.GetArchitecture());
 
@@ -748,7 +745,7 @@ size_t ObjectFileELF::GetModuleSpecifications(
                     data.SetData(data_sp);
                 }
                 ProgramHeaderColl program_headers;
-                GetProgramHeaderInfo(program_headers, set_data, header);
+                GetProgramHeaderInfo(program_headers, data, header);
 
                 size_t segment_data_end = 0;
                 for (ProgramHeaderCollConstIter I = program_headers.begin();
@@ -950,29 +947,7 @@ size_t ObjectFileELF::SectionIndex(const SectionHeaderCollConstIter &I) const {
 
 bool ObjectFileELF::ParseHeader() {
   lldb::offset_t offset = 0;
-  if (!m_header.Parse(m_data, &offset))
-    return false;
-
-  if (!IsInMemory())
-    return true;
-
-  // For in memory object files m_data might not contain the full object file.
-  // Try to load it
-  // until the end of the "Section header table" what is at the end of the ELF
-  // file.
-  addr_t file_size = m_header.e_shoff + m_header.e_shnum * m_header.e_shentsize;
-  if (m_data.GetByteSize() < file_size) {
-    ProcessSP process_sp(m_process_wp.lock());
-    if (!process_sp)
-      return false;
-
-    DataBufferSP data_sp = ReadMemory(process_sp, m_memory_addr, file_size);
-    if (!data_sp)
-      return false;
-    m_data.SetData(data_sp, 0, file_size);
-  }
-
-  return true;
+  return m_header.Parse(m_data, &offset);
 }
 
 bool ObjectFileELF::GetUUID(lldb_private::UUID *uuid) {
@@ -1188,7 +1163,7 @@ size_t ObjectFileELF::ParseDependentModules() {
 // GetProgramHeaderInfo
 //----------------------------------------------------------------------
 size_t ObjectFileELF::GetProgramHeaderInfo(ProgramHeaderColl &program_headers,
-                                           const SetDataFunction &set_data,
+                                           DataExtractor &object_data,
                                            const ELFHeader &header) {
   // We have already parsed the program headers
   if (!program_headers.empty())
@@ -1205,7 +1180,7 @@ size_t ObjectFileELF::GetProgramHeaderInfo(ProgramHeaderColl &program_headers,
   const size_t ph_size = header.e_phnum * header.e_phentsize;
   const elf_off ph_offset = header.e_phoff;
   DataExtractor data;
-  if (set_data(data, ph_offset, ph_size) != ph_size)
+  if (data.SetData(object_data, ph_offset, ph_size) != ph_size)
     return 0;
 
   uint32_t idx;
@@ -1225,12 +1200,7 @@ size_t ObjectFileELF::GetProgramHeaderInfo(ProgramHeaderColl &program_headers,
 // ParseProgramHeaders
 //----------------------------------------------------------------------
 size_t ObjectFileELF::ParseProgramHeaders() {
-  using namespace std::placeholders;
-  return GetProgramHeaderInfo(
-      m_program_headers,
-      std::bind(&ObjectFileELF::SetDataWithReadMemoryFallback, this, _1, _2,
-                _3),
-      m_header);
+  return GetProgramHeaderInfo(m_program_headers, m_data, m_header);
 }
 
 lldb_private::Status
@@ -1562,7 +1532,7 @@ void ObjectFileELF::ParseARMAttributes(DataExtractor &data, uint64_t length,
 // GetSectionHeaderInfo
 //----------------------------------------------------------------------
 size_t ObjectFileELF::GetSectionHeaderInfo(SectionHeaderColl &section_headers,
-                                           const SetDataFunction &set_data,
+                                           DataExtractor &object_data,
                                            const elf::ELFHeader &header,
                                            lldb_private::UUID &uuid,
                                            std::string &gnu_debuglink_file,
@@ -1634,7 +1604,7 @@ size_t ObjectFileELF::GetSectionHeaderInfo(SectionHeaderColl &section_headers,
   const size_t sh_size = header.e_shnum * header.e_shentsize;
   const elf_off sh_offset = header.e_shoff;
   DataExtractor sh_data;
-  if (set_data(sh_data, sh_offset, sh_size) != sh_size)
+  if (sh_data.SetData(object_data, sh_offset, sh_size) != sh_size)
     return 0;
 
   uint32_t idx;
@@ -1653,7 +1623,7 @@ size_t ObjectFileELF::GetSectionHeaderInfo(SectionHeaderColl &section_headers,
     const Elf64_Off offset = sheader.sh_offset;
     lldb_private::DataExtractor shstr_data;
 
-    if (set_data(shstr_data, offset, byte_size) == byte_size) {
+    if (shstr_data.SetData(object_data, offset, byte_size) == byte_size) {
       for (SectionHeaderCollIter I = section_headers.begin();
            I != section_headers.end(); ++I) {
         static ConstString g_sect_name_gnu_debuglink(".gnu_debuglink");
@@ -1669,8 +1639,8 @@ size_t ObjectFileELF::GetSectionHeaderInfo(SectionHeaderColl &section_headers,
           DataExtractor data;
           if (sheader.sh_type == SHT_MIPS_ABIFLAGS) {
 
-            if (section_size && (set_data(data, sheader.sh_offset,
-                                          section_size) == section_size)) {
+            if (section_size && (data.SetData(object_data, sheader.sh_offset,
+                                              section_size) == section_size)) {
               // MIPS ASE Mask is at offset 12 in MIPS.abiflags section
               lldb::offset_t offset = 12; // MIPS ABI Flags Version: 0
               arch_flags |= data.GetU32(&offset);
@@ -1735,14 +1705,14 @@ size_t ObjectFileELF::GetSectionHeaderInfo(SectionHeaderColl &section_headers,
           DataExtractor data;
 
           if (sheader.sh_type == SHT_ARM_ATTRIBUTES && section_size != 0 &&
-              set_data(data, sheader.sh_offset, section_size) == section_size)
+              data.SetData(object_data, sheader.sh_offset, section_size) == section_size)
             ParseARMAttributes(data, section_size, arch_spec);
         }
 
         if (name == g_sect_name_gnu_debuglink) {
           DataExtractor data;
-          if (section_size && (set_data(data, sheader.sh_offset,
-                                        section_size) == section_size)) {
+          if (section_size && (data.SetData(object_data, sheader.sh_offset,
+                                            section_size) == section_size)) {
             lldb::offset_t gnu_debuglink_offset = 0;
             gnu_debuglink_file = data.GetCStr(&gnu_debuglink_offset);
             gnu_debuglink_offset = llvm::alignTo(gnu_debuglink_offset, 4);
@@ -1762,8 +1732,8 @@ size_t ObjectFileELF::GetSectionHeaderInfo(SectionHeaderColl &section_headers,
         if (is_note_header) {
           // Allow notes to refine module info.
           DataExtractor data;
-          if (section_size && (set_data(data, sheader.sh_offset,
-                                        section_size) == section_size)) {
+          if (section_size && (data.SetData(object_data, sheader.sh_offset,
+                                            section_size) == section_size)) {
             Status error = RefineModuleDetailsFromNote(data, arch_spec, uuid);
             if (error.Fail()) {
               if (log)
@@ -1819,40 +1789,9 @@ ObjectFileELF::StripLinkerSymbolAnnotations(llvm::StringRef symbol_name) const {
 // ParseSectionHeaders
 //----------------------------------------------------------------------
 size_t ObjectFileELF::ParseSectionHeaders() {
-  using namespace std::placeholders;
-
-  return GetSectionHeaderInfo(
-      m_section_headers,
-      std::bind(&ObjectFileELF::SetDataWithReadMemoryFallback, this, _1, _2,
-                _3),
-      m_header, m_uuid, m_gnu_debuglink_file, m_gnu_debuglink_crc, m_arch_spec);
-}
-
-lldb::offset_t ObjectFileELF::SetData(const lldb_private::DataExtractor &src,
-                                      lldb_private::DataExtractor &dst,
-                                      lldb::offset_t offset,
-                                      lldb::offset_t length) {
-  return dst.SetData(src, offset, length);
-}
-
-lldb::offset_t
-ObjectFileELF::SetDataWithReadMemoryFallback(lldb_private::DataExtractor &dst,
-                                             lldb::offset_t offset,
-                                             lldb::offset_t length) {
-  if (offset + length <= m_data.GetByteSize())
-    return dst.SetData(m_data, offset, length);
-
-  const auto process_sp = m_process_wp.lock();
-  if (process_sp != nullptr) {
-    addr_t file_size = offset + length;
-
-    DataBufferSP data_sp = ReadMemory(process_sp, m_memory_addr, file_size);
-    if (!data_sp)
-      return false;
-    m_data.SetData(data_sp, 0, file_size);
-  }
-
-  return dst.SetData(m_data, offset, length);
+  return GetSectionHeaderInfo(m_section_headers, m_data, m_header, m_uuid,
+                              m_gnu_debuglink_file, m_gnu_debuglink_crc,
+                              m_arch_spec);
 }
 
 const ObjectFileELF::ELFSectionHeaderInfo *