Add checks to the MachOObjectFile() constructor to make sure load commands sizes

are the correct multiple.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@274798 91177308-0d34-0410-b5e6-96231b3b80d8

Author: enderby

lib/Object/MachOObjectFile.cpp

@@ -297,6 +297,25 @@ MachOObjectFile::MachOObjectFile(MemoryBufferRef Object, bool IsLittleEndian,
   }
 
   for (unsigned I = 0; I < LoadCommandCount; ++I) {
+    if (is64Bit()) {
+      if (Load.C.cmdsize % 8 != 0) {
+        // We have a hack here to allow 64-bit Mach-O core files to have
+        // LC_THREAD commands that are only a multiple of 4 and not 8 to be
+        // allowed since the macOS kernel produces them.
+        if (getHeader().filetype != MachO::MH_CORE ||
+            Load.C.cmd != MachO::LC_THREAD || Load.C.cmdsize % 4) {
+          Err = malformedError("load command " + Twine(I) + " cmdsize not a "
+                               "multiple of 8");
+          return;
+        }
+      }
+    } else {
+      if (Load.C.cmdsize % 4 != 0) {
+        Err = malformedError("load command " + Twine(I) + " cmdsize not a "
+                             "multiple of 4");
+        return;
+      }
+    }
     LoadCommands.push_back(Load);
     if (Load.C.cmd == MachO::LC_SYMTAB) {
       // Multiple symbol tables

test/Object/macho-invalid.test

@@ -24,13 +24,16 @@ RUN:      | FileCheck -check-prefix SMALL-LOADC-SIZE-1 %s
 SMALL-LOADC-SIZE-1: truncated or malformed object (load command 1 with size less than 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
+RUN:      | FileCheck -check-prefix MULTIPLE-NOT-4 %s
+MULTIPLE-NOT-4: truncated or malformed object (load command 0 cmdsize not a multiple of 4)
+
 RUN: not llvm-objdump -private-headers %p/Inputs/macho-invalid-too-small-segment-load-command.1 2>&1 \
 RUN:      | FileCheck -check-prefix SMALL-SEGLOADC-SIZE %s
 SMALL-SEGLOADC-SIZE: truncated or malformed object (load command 0 LC_SEGMENT cmdsize too small)
+
 RUN: not llvm-objdump -private-headers %p/Inputs/macho64-invalid-too-small-segment-load-command 2>&1 \
-RUN:      | FileCheck -check-prefix SMALL-SEGLOADC-SIZE-64 %s
-SMALL-SEGLOADC-SIZE-64: truncated or malformed object (load command 0 LC_SEGMENT_64 cmdsize too small)
+RUN:      | FileCheck -check-prefix MULTIPLE-NOT-8 %s
+MULTIPLE-NOT-8: truncated or malformed object (load command 0 cmdsize not a multiple of 8)
 
 RUN: not llvm-objdump -private-headers %p/Inputs/macho-invalid-no-size-for-sections 2>&1 \
 RUN:      | FileCheck -check-prefix TOO-MANY-SECTS %s