feat: add uppercase transformation (#935)

* add uppercase transformation
* add uppercase.json for tests

---------

Co-authored-by: Felipe Zipitría <[email protected]>

Author: blotus

Diff for: internal/transformations/testdata/uppercase.json

@@ -0,0 +1,38 @@
+[
+	{
+	   "input" : "",
+	   "name" : "uppercase",
+	   "type" : "tfn",
+	   "ret" : 0,
+	   "output" : ""
+	},
+	{
+	   "output" : "TESTCASE",
+	   "ret" : 0,
+	   "name" : "uppercase",
+	   "input" : "testcase",
+	   "type" : "tfn"
+	},
+	{
+	   "ret" : 0,
+	   "input" : "test\u0000case",
+	   "type" : "tfn",
+	   "name" : "uppercase",
+	   "output" : "TEST\u0000CASE"
+	},
+	{
+	   "output" : "TESTCASE",
+	   "input" : "testcase",
+	   "name" : "uppercase",
+	   "type" : "tfn",
+	   "ret" : 1
+	},
+	{
+	   "ret" : 1,
+	   "input" : "Test\u0000Case",
+	   "name" : "uppercase",
+	   "type" : "tfn",
+	   "output" : "TEST\u0000CASE"
+	}
+ ]
+ 

Diff for: internal/transformations/transformations.go

@@ -51,6 +51,7 @@ func init() {
 	Register("replaceComments", replaceComments)
 	Register("replaceNulls", replaceNulls)
 	Register("sha1", sha1T)
+	Register("uppercase", upperCase)
 	Register("urlDecode", urlDecode)
 	Register("urlDecodeUni", urlDecodeUni)
 	Register("urlEncode", urlEncode)

Diff for: internal/transformations/uppercase.go

@@ -0,0 +1,15 @@
+// Copyright 2022 Juan Pablo Tosso and the OWASP Coraza contributors
+// SPDX-License-Identifier: Apache-2.0
+
+package transformations
+
+import (
+	"strings"
+)
+
+func upperCase(data string) (string, bool, error) {
+	// TODO: Explicit implementation of ToUpper would allow optimizing away the byte by byte comparison for returning the changed boolean
+	// See https://github.com/corazawaf/coraza/pull/778#discussion_r1186963422
+	transformedData := strings.ToUpper(data)
+	return transformedData, data != transformedData, nil
+}

Diff for: internal/transformations/uppercase_test.go

@@ -0,0 +1,69 @@
+// Copyright 2022 Juan Pablo Tosso and the OWASP Coraza contributors
+// SPDX-License-Identifier: Apache-2.0
+
+package transformations
+
+import "testing"
+
+func TestUpperCase(t *testing.T) {
+	tests := []struct {
+		input string
+		want  string
+	}{
+		{
+			input: "TestCase",
+			want:  "TESTCASE",
+		},
+		{
+			input: "test\u0000case",
+			want:  "TEST\u0000CASE",
+		},
+		{
+			input: "TESTCASE",
+			want:  "TESTCASE",
+		},
+		{
+			input: "",
+			want:  "",
+		},
+		{
+			input: "ThIs Is A tExT fOr TeStInG uPPerCAse FuNcTiOnAlItY.",
+			want:  "THIS IS A TEXT FOR TESTING UPPERCASE FUNCTIONALITY.",
+		},
+	}
+
+	for _, tc := range tests {
+		tt := tc
+		t.Run(tt.input, func(t *testing.T) {
+			have, changed, err := upperCase(tt.input)
+			if err != nil {
+				t.Error(err)
+			}
+			if tt.input == tt.want && changed || tt.input != tt.want && !changed {
+				t.Errorf("input %q, have %q with changed %t", tt.input, have, changed)
+			}
+			if have != tt.want {
+				t.Errorf("have %q, want %q", have, tt.want)
+			}
+		})
+	}
+}
+
+func BenchmarkUppercase(b *testing.B) {
+	tests := []string{
+		"tesTcase",
+		"ThIs Is A tExT fOr TeStInG lOwErCaSe FuNcTiOnAlItY.ThIs Is A tExT fOr TeStInG lOwErCaSe FuNcTiOnAlItY. ThIs Is A tExT fOr TeStInG lOwErCaSe FuNcTiOnAlItY.ThIs Is A tExT fOr TeStInG lOwErCaSe FuNcTiOnAlItY.",
+	}
+	for i := 0; i < b.N; i++ {
+		for _, tt := range tests {
+			b.Run(tt, func(b *testing.B) {
+				for j := 0; j < b.N; j++ {
+					_, _, err := upperCase(tt)
+					if err != nil {
+						b.Error(err)
+					}
+				}
+			})
+		}
+	}
+}