From d7d84b3be6c929ee9d1b425a82b7121936a7cd34 Mon Sep 17 00:00:00 2001
From: iximeow <me@iximeow.net>
Date: Sat, 16 Dec 2023 15:05:08 -0800
Subject: fix incorrect register selection for `vpmov*2m` with `rex.r` set

---
 CHANGELOG                  | 6 ++++++
 src/shared/evex.in         | 3 +++
 test/long_mode/mod.rs      | 4 ++++
 test/protected_mode/mod.rs | 5 +++++
 test/real_mode/mod.rs      | 5 +++++
 5 files changed, 23 insertions(+)

diff --git a/CHANGELOG b/CHANGELOG
index 4210e30..5d8ae65 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -13,6 +13,12 @@
   instructions are otherwise decoded correctly.)
 * fix incorrect register selection for `vpmovm2*` with `rex.b` set (would select
   registers "k8" through "k15", but should be masked down to "k0".."k7".)
+* fix incorrect register selection for `vpmov*2m` with `rex.r` set. similar to
+  above, except 64-bit only: in 32- and 16-bit modes, this case was and continues
+  to be a `bound` instruction. in 64-bit mode, this would disassemble as a
+  `vpmov*2m` with nonsense `k8..k15` selected. to real hardware, this bit
+  sequence is an invalid instruction, and so it is now invalid to yaxpeax-x86
+  as well.
 
 ## 1.2.0
 * fix incorrect old yaxpeax-arch version selection for ffi crates
diff --git a/src/shared/evex.in b/src/shared/evex.in
index 837b867..58ec14a 100644
--- a/src/shared/evex.in
+++ b/src/shared/evex.in
@@ -2810,6 +2810,9 @@ pub(crate) fn read_evex_operands<
       if mem_oper == OperandSpec::RegMMM {
         instruction.mem_size = 0;
         instruction.regs[0].bank = RegisterBank::K;
+        if instruction.regs[0].num > 7 {
+          return Err(DecodeError::InvalidOperand);
+        }
       } else {
         return Err(DecodeError::InvalidOperand);
       }
diff --git a/test/long_mode/mod.rs b/test/long_mode/mod.rs
index c7a4788..b087d74 100644
--- a/test/long_mode/mod.rs
+++ b/test/long_mode/mod.rs
@@ -1470,6 +1470,10 @@ fn evex() {
     // modrm bits as a register selector. out-of-range `k` seem to just get masked down..
     test_display(&[0x62, 0xd2, 0x7e, 0x08, 0x28, 0xc2], "vpmovm2b xmm0, k2");
     test_display(&[0x62, 0xf2, 0x7e, 0x08, 0x28, 0xc1], "vpmovm2b xmm0, k1");
+    // vpmovb2m (and larger forms). out-of-range `k` are invalid in 64-bit mode, are part of the
+    // `bound` instruction for 32- and 16-bit modes.
+    test_invalid(&[0x62, 0x72, 0x7e, 0x28, 0x29, 0xfd]);
+    test_display(&[0x62, 0xf2, 0x7e, 0x28, 0x29, 0xfd], "vpmovb2m k7, ymm5");
 
     test_display(&[0x62, 0x12, 0x7d, 0x06, 0xa0, 0x04, 0x2f], "vpscatterdd dword [r15 + xmm29 * 1], k6, xmm8");
     test_display(&[0x62, 0x12, 0x7d, 0x06, 0xa0, 0x14, 0x0f], "vpscatterdd dword [r15 + xmm25 * 1], k6, xmm10");
diff --git a/test/protected_mode/mod.rs b/test/protected_mode/mod.rs
index e843c7a..88d6c49 100644
--- a/test/protected_mode/mod.rs
+++ b/test/protected_mode/mod.rs
@@ -1337,6 +1337,11 @@ fn evex() {
     test_display(&[0x62, 0xd2, 0x7e, 0x08, 0x28, 0xc2], "vpmovm2b xmm0, k2");
     test_display(&[0x62, 0xf2, 0x7e, 0x08, 0x28, 0xc1], "vpmovm2b xmm0, k1");
 
+    // vpmovb2m (and larger forms). out-of-range `k` are invalid in 64-bit mode, are part of the
+    // `bound` instruction for 32- and 16-bit modes.
+    test_display(&[0x62, 0x72, 0x7e /* , 0x28, 0x29, 0xfd */], "bound esi, qword [edx + 0x7e]");
+    test_display(&[0x62, 0xf2, 0x7e, 0x28, 0x29, 0xfd], "vpmovb2m k7, ymm5");
+
     test_display(&[0x62, 0xf2, 0x7d, 0x48, 0x2a, 0x44, 0x40, 0x01], "vmovntdqa zmm0, zmmword [eax + eax * 2 + 0x40]");
     test_display(&[0x62, 0xf2, 0x7d, 0x08, 0x2a, 0x44, 0x40, 0x01], "vmovntdqa xmm0, xmmword [eax + eax * 2 + 0x10]");
 }
diff --git a/test/real_mode/mod.rs b/test/real_mode/mod.rs
index a321e64..b422887 100644
--- a/test/real_mode/mod.rs
+++ b/test/real_mode/mod.rs
@@ -18406,6 +18406,11 @@ fn test_invalid_sequences() {
     test_display(&[0x62, 0xd2, 0x7e, 0x08, 0x28, 0xc2], "vpmovm2b xmm0, k2");
     test_display(&[0x62, 0xf2, 0x7e, 0x08, 0x28, 0xc1], "vpmovm2b xmm0, k1");
 
+    // vpmovb2m (and larger forms). out-of-range `k` are invalid in 64-bit mode, are part of the
+    // `bound` instruction for 32- and 16-bit modes.
+    test_display(&[0x62, 0x72, 0x7e /* , 0x28, 0x29, 0xfd */], "bound si, dword [bp + si * 1 + 0x7e]");
+    test_display(&[0x62, 0xf2, 0x7e, 0x28, 0x29, 0xfd], "vpmovb2m k7, ymm5");
+
 }
 
 #[test]
-- 
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