Index: lib/Support/ARMAttributeParser.cpp
===================================================================
--- lib/Support/ARMAttributeParser.cpp
+++ lib/Support/ARMAttributeParser.cpp
@@ -709,6 +709,12 @@
       SW->indent();
     }
 
+    if (SectionLength == 0 || (SectionLength + Offset) > Section.size()) {
+      errs() << "invalid subsection length " << SectionLength << " at offset "
+             << Offset << "\n";
+      return;
+    }
+
     ParseSubsection(Section.data() + Offset, SectionLength);
     Offset = Offset + SectionLength;
 
Index: tools/lld/test/ELF/bad-arm-attributes.s
===================================================================
--- tools/lld/test/ELF/bad-arm-attributes.s
+++ tools/lld/test/ELF/bad-arm-attributes.s
@@ -0,0 +1,7 @@
+# RUN: llvm-mc -filetype=obj -triple=arm-unknown-linux %s -o %t
+# RUN: ld.lld %t -o %tout 2>&1 | FileCheck %s
+
+# CHECK: invalid subsection length 0 at offset 1
+
+.section .ARM.attributes,"a",%0x70000003
+  .quad 0
Index: tools/lld/test/ELF/bad-arm-attributes2.s
===================================================================
--- tools/lld/test/ELF/bad-arm-attributes2.s
+++ tools/lld/test/ELF/bad-arm-attributes2.s
@@ -0,0 +1,7 @@
+# RUN: llvm-mc -filetype=obj -triple=arm-unknown-linux %s -o %t
+# RUN: ld.lld %t -o %tout 2>&1 | FileCheck %s
+
+# CHECK: invalid subsection length 4294967295 at offset 1
+
+.section .ARM.attributes,"a",%0x70000003
+  .byte 0, 0xFF, 0xFF, 0xFF, 0xFF