[Xen-devel] [PATCH] x86/HVM: fix boundary check in hvmemul_insn_fetch() (again)

["Jan Beulich" <JBeulich@xxxxxxxx>]

Commit 5a992b670b ("x86/hvm: Fix boundary check in
hvmemul_insn_fetch()") went a little too far in its correction to
commit 0943a03037 ("x86/hvm: Fixes to hvmemul_insn_fetch()"): Keep the
start offset check, but restore the original end offset one.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -959,7 +959,7 @@ int hvmemul_insn_fetch(
              * which means something went wrong with instruction decoding...
              */
             if ( insn_off >= sizeof(hvmemul_ctxt->insn_buf) ||
-                 (insn_off + bytes) >= sizeof(hvmemul_ctxt->insn_buf) )
+                 insn_off + bytes > sizeof(hvmemul_ctxt->insn_buf) )
             {
                 ASSERT_UNREACHABLE();
                 return X86EMUL_UNHANDLEABLE;




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