From 43a123c1ae6613b3efeed291fa552ecd909d3acf Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Tue, 16 Apr 2024 21:23:18 +0200
Subject: Adding upstream version 1.20.14.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 src/crypto/internal/alias/alias.go      | 30 +++++++++++++++++++++
 src/crypto/internal/alias/alias_test.go | 46 +++++++++++++++++++++++++++++++++
 2 files changed, 76 insertions(+)
 create mode 100644 src/crypto/internal/alias/alias.go
 create mode 100644 src/crypto/internal/alias/alias_test.go

(limited to 'src/crypto/internal/alias')

diff --git a/src/crypto/internal/alias/alias.go b/src/crypto/internal/alias/alias.go
new file mode 100644
index 0000000..936cc25
--- /dev/null
+++ b/src/crypto/internal/alias/alias.go
@@ -0,0 +1,30 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package alias implements memory alaising tests.
+// This code also exists as golang.org/x/crypto/internal/alias.
+package alias
+
+import "unsafe"
+
+// AnyOverlap reports whether x and y share memory at any (not necessarily
+// corresponding) index. The memory beyond the slice length is ignored.
+func AnyOverlap(x, y []byte) bool {
+	return len(x) > 0 && len(y) > 0 &&
+		uintptr(unsafe.Pointer(&x[0])) <= uintptr(unsafe.Pointer(&y[len(y)-1])) &&
+		uintptr(unsafe.Pointer(&y[0])) <= uintptr(unsafe.Pointer(&x[len(x)-1]))
+}
+
+// InexactOverlap reports whether x and y share memory at any non-corresponding
+// index. The memory beyond the slice length is ignored. Note that x and y can
+// have different lengths and still not have any inexact overlap.
+//
+// InexactOverlap can be used to implement the requirements of the crypto/cipher
+// AEAD, Block, BlockMode and Stream interfaces.
+func InexactOverlap(x, y []byte) bool {
+	if len(x) == 0 || len(y) == 0 || &x[0] == &y[0] {
+		return false
+	}
+	return AnyOverlap(x, y)
+}
diff --git a/src/crypto/internal/alias/alias_test.go b/src/crypto/internal/alias/alias_test.go
new file mode 100644
index 0000000..a68fb33
--- /dev/null
+++ b/src/crypto/internal/alias/alias_test.go
@@ -0,0 +1,46 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package alias
+
+import "testing"
+
+var a, b [100]byte
+
+var aliasingTests = []struct {
+	x, y                       []byte
+	anyOverlap, inexactOverlap bool
+}{
+	{a[:], b[:], false, false},
+	{a[:], b[:0], false, false},
+	{a[:], b[:50], false, false},
+	{a[40:50], a[50:60], false, false},
+	{a[40:50], a[60:70], false, false},
+	{a[:51], a[50:], true, true},
+	{a[:], a[:], true, false},
+	{a[:50], a[:60], true, false},
+	{a[:], nil, false, false},
+	{nil, nil, false, false},
+	{a[:], a[:0], false, false},
+	{a[:10], a[:10:20], true, false},
+	{a[:10], a[5:10:20], true, true},
+}
+
+func testAliasing(t *testing.T, i int, x, y []byte, anyOverlap, inexactOverlap bool) {
+	any := AnyOverlap(x, y)
+	if any != anyOverlap {
+		t.Errorf("%d: wrong AnyOverlap result, expected %v, got %v", i, anyOverlap, any)
+	}
+	inexact := InexactOverlap(x, y)
+	if inexact != inexactOverlap {
+		t.Errorf("%d: wrong InexactOverlap result, expected %v, got %v", i, inexactOverlap, any)
+	}
+}
+
+func TestAliasing(t *testing.T) {
+	for i, tt := range aliasingTests {
+		testAliasing(t, i, tt.x, tt.y, tt.anyOverlap, tt.inexactOverlap)
+		testAliasing(t, i, tt.y, tt.x, tt.anyOverlap, tt.inexactOverlap)
+	}
+}
-- 
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