Next set of additional error checks for invalid Mach-O files.

This contains the two missing checks for LC_SEGMENT load command fields.
And checks for the Mach-O sections fields that would make them invalid.

With the new checks, some of the existing malformed file checks now trips one
of these instead of the issue it was having before so those tests were adjusted.

llvm-svn: 278557

1 files changed, 96 insertions, 17 deletions

diff --git a/llvm/lib/Object/MachOObjectFile.cpp b/llvm/lib/Object/MachOObjectFile.cpp
index 863081fbd4c..f34e68721c0 100644
--- a/llvm/lib/Object/MachOObjectFile.cpp
+++ b/llvm/lib/Object/MachOObjectFile.cpp
@@ -219,19 +219,19 @@ static void parseHeader(const MachOObjectFile *Obj, T &Header,
 // Parses LC_SEGMENT or LC_SEGMENT_64 load command, adds addresses of all
 // sections to \param Sections, and optionally sets
 // \param IsPageZeroSegment to true.
-template <typename SegmentCmd>
+template <typename Segment, typename Section>
 static Error parseSegmentLoadCommand(
     const MachOObjectFile *Obj, const MachOObjectFile::LoadCommandInfo &Load,
     SmallVectorImpl<const char *> &Sections, bool &IsPageZeroSegment,
-    uint32_t LoadCommandIndex, const char *CmdName) {
-  const unsigned SegmentLoadSize = sizeof(SegmentCmd);
+    uint32_t LoadCommandIndex, const char *CmdName, uint64_t SizeOfHeaders) {
+  const unsigned SegmentLoadSize = sizeof(Segment);
   if (Load.C.cmdsize < SegmentLoadSize)
     return malformedError("load command " + Twine(LoadCommandIndex) +
                           " " + CmdName + " cmdsize too small");
-  if (auto SegOrErr = getStructOrErr<SegmentCmd>(Obj, Load.Ptr)) {
-    SegmentCmd S = SegOrErr.get();
-    const unsigned SectionSize =
-      Obj->is64Bit() ? sizeof(MachO::section_64) : sizeof(MachO::section);
+  if (auto SegOrErr = getStructOrErr<Segment>(Obj, Load.Ptr)) {
+    Segment S = SegOrErr.get();
+    const unsigned SectionSize = sizeof(Section);
+    uint64_t FileSize = Obj->getData().size();
     if (S.nsects > std::numeric_limits<uint32_t>::max() / SectionSize ||
         S.nsects * SectionSize > Load.C.cmdsize - SegmentLoadSize)
       return malformedError("load command " + Twine(LoadCommandIndex) +
@@ -240,12 +240,88 @@ static Error parseSegmentLoadCommand(
     for (unsigned J = 0; J < S.nsects; ++J) {
       const char *Sec = getSectionPtr(Obj, Load, J);
       Sections.push_back(Sec);
+      Section s = getStruct<Section>(Obj, Sec);
+      if (Obj->getHeader().filetype != MachO::MH_DYLIB_STUB &&
+          Obj->getHeader().filetype != MachO::MH_DSYM &&
+          s.flags != MachO::S_ZEROFILL &&
+          s.flags != MachO::S_THREAD_LOCAL_ZEROFILL &&
+          s.offset > FileSize)
+        return malformedError("offset field of section " + Twine(J) + " in " +
+                              CmdName + " command " + Twine(LoadCommandIndex) +
+                              " extends past the end of the file");
+      if (Obj->getHeader().filetype != MachO::MH_DYLIB_STUB &&
+          Obj->getHeader().filetype != MachO::MH_DSYM &&
+          s.flags != MachO::S_ZEROFILL &&
+          s.flags != MachO::S_THREAD_LOCAL_ZEROFILL &&
+	  S.fileoff == 0 && s.offset < SizeOfHeaders && s.size != 0)
+        return malformedError("offset field of section " + Twine(J) + " in " +
+                              CmdName + " command " + Twine(LoadCommandIndex) +
+                              " not past the headers of the file");
+      uint64_t BigSize = s.offset;
+      BigSize += s.size;
+      if (Obj->getHeader().filetype != MachO::MH_DYLIB_STUB &&
+          Obj->getHeader().filetype != MachO::MH_DSYM &&
+          s.flags != MachO::S_ZEROFILL &&
+          s.flags != MachO::S_THREAD_LOCAL_ZEROFILL &&
+          BigSize > FileSize)
+        return malformedError("offset field plus size field of section " +
+                              Twine(J) + " in " + CmdName + " command " +
+                              Twine(LoadCommandIndex) +
+                              " extends past the end of the file");
+      if (Obj->getHeader().filetype != MachO::MH_DYLIB_STUB &&
+          Obj->getHeader().filetype != MachO::MH_DSYM &&
+          s.flags != MachO::S_ZEROFILL &&
+          s.flags != MachO::S_THREAD_LOCAL_ZEROFILL &&
+          s.size > S.filesize)
+        return malformedError("size field of section " +
+                              Twine(J) + " in " + CmdName + " command " +
+                              Twine(LoadCommandIndex) +
+                              " greater than the segment");
+      if (Obj->getHeader().filetype != MachO::MH_DYLIB_STUB &&
+          Obj->getHeader().filetype != MachO::MH_DSYM &&
+          s.size != 0 && s.addr < S.vmaddr)
+        return malformedError("addr field of section " +
+                              Twine(J) + " in " + CmdName + " command " +
+			      Twine(LoadCommandIndex) +
+			      " less than the segment's vmaddr");
+      BigSize = s.addr;
+      BigSize += s.size;
+      uint64_t BigEnd = S.vmaddr;
+      BigEnd += S.vmsize;
+      if (S.vmsize != 0 && s.size != 0 && BigSize > BigEnd)
+        return malformedError("addr field plus size of section " +
+                              Twine(J) + " in " + CmdName + " command " +
+			      Twine(LoadCommandIndex) + " greater than than "
+                              "the segment's vmaddr plus vmsize");
+      if (s.reloff > FileSize)
+        return malformedError("reloff field of section " +
+                              Twine(J) + " in " + CmdName + " command " +
+			      Twine(LoadCommandIndex) +
+                              " extends past the end of the file");
+      BigSize = s.nreloc;
+      BigSize *= sizeof(struct MachO::relocation_info);
+      BigSize += s.reloff;
+      if (BigSize > FileSize)
+        return malformedError("reloff field plus nreloc field times sizeof("
+                              "struct relocation_info) of section " +
+                              Twine(J) + " in " + CmdName + " command " +
+			      Twine(LoadCommandIndex) +
+                              " extends past the end of the file");
     }
-    uint64_t FileSize = Obj->getData().size();
     if (S.fileoff > FileSize)
       return malformedError("load command " + Twine(LoadCommandIndex) +
                             " fileoff field in " + CmdName + 
                             " extends past the end of the file");
+    uint64_t BigSize = S.fileoff;
+    BigSize += S.filesize;
+    if (BigSize > FileSize)
+      return malformedError("load command " + Twine(LoadCommandIndex) +
+                            " fileoff field plus filesize field in " +
+                            CmdName + " extends past the end of the file");
+    if (S.vmsize != 0 && S.filesize > S.vmsize)
+      return malformedError("load command " + Twine(LoadCommandIndex) +
+                            " fileoff field in " + CmdName +
+                            " greater than vmsize field");
     IsPageZeroSegment |= StringRef("__PAGEZERO").equals(S.segname);
   } else
     return SegOrErr.takeError();
@@ -273,18 +349,18 @@ MachOObjectFile::MachOObjectFile(MemoryBufferRef Object, bool IsLittleEndian,
       DyldInfoLoadCmd(nullptr), UuidLoadCmd(nullptr),
       HasPageZeroSegment(false) {
   ErrorAsOutParameter ErrAsOutParam(&Err);
-  uint64_t BigSize;
+  uint64_t SizeOfHeaders;
   if (is64Bit()) {
     parseHeader(this, Header64, Err);
-    BigSize = sizeof(MachO::mach_header_64);
+    SizeOfHeaders = sizeof(MachO::mach_header_64);
   } else {
     parseHeader(this, Header, Err);
-    BigSize = sizeof(MachO::mach_header);
+    SizeOfHeaders = sizeof(MachO::mach_header);
   }
   if (Err)
     return;
-  BigSize += getHeader().sizeofcmds;
-  if (getData().data() + BigSize > getData().end()) {
+  SizeOfHeaders += getHeader().sizeofcmds;
+  if (getData().data() + SizeOfHeaders > getData().end()) {
     Err = malformedError("load commands extend past the end of the file");
     return;
   }
@@ -366,13 +442,16 @@ MachOObjectFile::MachOObjectFile(MemoryBufferRef Object, bool IsLittleEndian,
       }
       UuidLoadCmd = Load.Ptr;
     } else if (Load.C.cmd == MachO::LC_SEGMENT_64) {
-      if ((Err = parseSegmentLoadCommand<MachO::segment_command_64>(
+      if ((Err = parseSegmentLoadCommand<MachO::segment_command_64,
+                                         MachO::section_64>(
                    this, Load, Sections, HasPageZeroSegment, I,
-                   "LC_SEGMENT_64")))
+                   "LC_SEGMENT_64", SizeOfHeaders)))
         return;
     } else if (Load.C.cmd == MachO::LC_SEGMENT) {
-      if ((Err = parseSegmentLoadCommand<MachO::segment_command>(
-                   this, Load, Sections, HasPageZeroSegment, I, "LC_SEGMENT")))
+      if ((Err = parseSegmentLoadCommand<MachO::segment_command,
+                                         MachO::section>(
+                   this, Load, Sections, HasPageZeroSegment, I,
+                   "LC_SEGMENT", SizeOfHeaders)))
         return;
     } else if (Load.C.cmd == MachO::LC_LOAD_DYLIB ||
                Load.C.cmd == MachO::LC_LOAD_WEAK_DYLIB ||