[llvm] r239080 - [Object, MachO] Don't crash on invalid MachO load commands.

Alexey Samsonov vonosmas at gmail.com
Thu Jun 4 12:57:46 PDT 2015


Author: samsonov
Date: Thu Jun  4 14:57:46 2015
New Revision: 239080

URL: http://llvm.org/viewvc/llvm-project?rev=239080&view=rev
Log:
[Object, MachO] Don't crash on invalid MachO load commands.

Summary:
Currently all load commands are parsed in MachOObjectFile constructor.
If the next load command cannot be parsed, or if command size is too
small, properly report it through the error code and fail to construct
the object, instead of crashing the program.

Test Plan: regression test suite

Reviewers: rafael, filcab

Subscribers: llvm-commits

Modified:
    llvm/trunk/include/llvm/Object/Error.h
    llvm/trunk/lib/Object/Error.cpp
    llvm/trunk/lib/Object/MachOObjectFile.cpp
    llvm/trunk/test/Object/macho-invalid.test

Modified: llvm/trunk/include/llvm/Object/Error.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Object/Error.h?rev=239080&r1=239079&r2=239080&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Object/Error.h (original)
+++ llvm/trunk/include/llvm/Object/Error.h Thu Jun  4 14:57:46 2015
@@ -28,6 +28,7 @@ enum class object_error {
   parse_failed,
   unexpected_eof,
   bitcode_section_not_found,
+  macho_small_load_command,
 };
 
 inline std::error_code make_error_code(object_error e) {

Modified: llvm/trunk/lib/Object/Error.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Object/Error.cpp?rev=239080&r1=239079&r2=239080&view=diff
==============================================================================
--- llvm/trunk/lib/Object/Error.cpp (original)
+++ llvm/trunk/lib/Object/Error.cpp Thu Jun  4 14:57:46 2015
@@ -44,6 +44,8 @@ std::string _object_error_category::mess
     return "The end of the file was unexpectedly encountered";
   case object_error::bitcode_section_not_found:
     return "Bitcode section not found in object file";
+  case object_error::macho_small_load_command:
+    return "Mach-O load command with size < 8 bytes";
   }
   llvm_unreachable("An enumerator of object_error does not have a message "
                    "defined.");

Modified: llvm/trunk/lib/Object/MachOObjectFile.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Object/MachOObjectFile.cpp?rev=239080&r1=239079&r2=239080&view=diff
==============================================================================
--- llvm/trunk/lib/Object/MachOObjectFile.cpp (original)
+++ llvm/trunk/lib/Object/MachOObjectFile.cpp Thu Jun  4 14:57:46 2015
@@ -194,24 +194,27 @@ static uint32_t getSectionFlags(const Ma
   return Sect.flags;
 }
 
-static MachOObjectFile::LoadCommandInfo
+static ErrorOr<MachOObjectFile::LoadCommandInfo>
 getLoadCommandInfo(const MachOObjectFile *Obj, const char *Ptr) {
+  auto CmdOrErr = getStructOrErr<MachO::load_command>(Obj, Ptr);
+  if (!CmdOrErr)
+    return CmdOrErr.getError();
+  if (CmdOrErr->cmdsize < 8)
+    return object_error::macho_small_load_command;
   MachOObjectFile::LoadCommandInfo Load;
   Load.Ptr = Ptr;
-  Load.C = getStruct<MachO::load_command>(Obj, Load.Ptr);
-  if (Load.C.cmdsize < 8)
-    report_fatal_error("Load command with size < 8 bytes.");
+  Load.C = CmdOrErr.get();
   return Load;
 }
 
-static MachOObjectFile::LoadCommandInfo
+static ErrorOr<MachOObjectFile::LoadCommandInfo>
 getFirstLoadCommandInfo(const MachOObjectFile *Obj) {
   unsigned HeaderSize = Obj->is64Bit() ? sizeof(MachO::mach_header_64)
                                        : sizeof(MachO::mach_header);
   return getLoadCommandInfo(Obj, getPtr(Obj, HeaderSize));
 }
 
-static MachOObjectFile::LoadCommandInfo
+static ErrorOr<MachOObjectFile::LoadCommandInfo>
 getNextLoadCommandInfo(const MachOObjectFile *Obj,
                        const MachOObjectFile::LoadCommandInfo &L) {
   return getLoadCommandInfo(Obj, L.Ptr + L.C.cmdsize);
@@ -251,7 +254,12 @@ MachOObjectFile::MachOObjectFile(MemoryB
   MachO::LoadCommandType SegmentLoadType = is64Bit() ?
     MachO::LC_SEGMENT_64 : MachO::LC_SEGMENT;
 
-  LoadCommandInfo Load = getFirstLoadCommandInfo(this);
+  auto LoadOrErr = getFirstLoadCommandInfo(this);
+  if (!LoadOrErr) {
+    EC = LoadOrErr.getError();
+    return;
+  }
+  LoadCommandInfo Load = LoadOrErr.get();
   for (unsigned I = 0; I < LoadCommandCount; ++I) {
     LoadCommands.push_back(Load);
     if (Load.C.cmd == MachO::LC_SYMTAB) {
@@ -318,8 +326,14 @@ MachOObjectFile::MachOObjectFile(MemoryB
                Load.C.cmd == MachO::LC_LOAD_UPWARD_DYLIB) {
       Libraries.push_back(Load.Ptr);
     }
-    if (I < LoadCommandCount - 1)
-      Load = getNextLoadCommandInfo(this, Load);
+    if (I < LoadCommandCount - 1) {
+      auto LoadOrErr = getNextLoadCommandInfo(this, Load);
+      if (!LoadOrErr) {
+        EC = LoadOrErr.getError();
+        return;
+      }
+      Load = LoadOrErr.get();
+    }
   }
   assert(LoadCommands.size() == LoadCommandCount);
 }

Modified: llvm/trunk/test/Object/macho-invalid.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Object/macho-invalid.test?rev=239080&r1=239079&r2=239080&view=diff
==============================================================================
--- llvm/trunk/test/Object/macho-invalid.test (original)
+++ llvm/trunk/test/Object/macho-invalid.test Thu Jun  4 14:57:46 2015
@@ -3,13 +3,13 @@ RUN: llvm-objdump -private-headers %p/In
 
 RUN: not llvm-objdump -private-headers %p/Inputs/macho64-invalid-incomplete-load-command 2>&1 \
 RUN:      | FileCheck -check-prefix INCOMPLETE-LOADC %s
-INCOMPLETE-LOADC: Malformed MachO file
+INCOMPLETE-LOADC: Invalid data was encountered while parsing the file.
 
 RUN: not llvm-objdump -private-headers %p/Inputs/macho-invalid-too-small-load-command 2>&1 \
 RUN:      | FileCheck -check-prefix SMALL-LOADC-SIZE %s
 RUN: not llvm-objdump -private-headers %p/Inputs/macho64-invalid-too-small-load-command 2>&1 \
 RUN:      | FileCheck -check-prefix SMALL-LOADC-SIZE %s
-SMALL-LOADC-SIZE: Load command with size < 8 bytes
+SMALL-LOADC-SIZE: Mach-O load command with size < 8 bytes
 
 RUN: not llvm-objdump -private-headers %p/Inputs/macho-invalid-too-small-segment-load-command 2>&1 \
 RUN:      | FileCheck -check-prefix SMALL-SEGLOADC-SIZE %s





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