MM-68439 Centralize filename handling for FileInfo (#36223) (#36255)

Automatic Merge

server/public/model/file_info_test.go

@@ -6,6 +6,7 @@ package model
 import (
 	_ "image/gif"
 	_ "image/png"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -60,6 +61,91 @@ func TestFileInfoIsValid(t *testing.T) {
 		assert.Nil(t, info.IsValid(), "creatorId isn't valid")
 		info.CreatorId = creatorId
 	})
+
+	t.Run("Empty Name is valid", func(t *testing.T) {
+		info.Name = ""
+		assert.Nil(t, info.IsValid())
+	})
+
+	t.Run("Non-empty Name must be a plain filename", func(t *testing.T) {
+		originalName := info.Name
+		defer func() { info.Name = originalName }()
+
+		badNames := []string{
+			".",
+			"..",
+			"../a.png",
+			`..\..\a.png`,
+			"foo/bar.png",
+			`foo\bar.png`,
+			"foo\x00.png",
+		}
+		for _, bad := range badNames {
+			info.Name = bad
+			assert.NotNilf(t, info.IsValid(), "expected %q to be rejected", bad)
+		}
+	})
+}
+
+func TestIsValidFilename(t *testing.T) {
+	cases := []struct {
+		name  string
+		valid bool
+	}{
+		{"hello.png", true},
+		{"hello world (1).png", true},
+		{"日本語.txt", true},
+		{"", false},
+		{".", false},
+		{"..", false},
+		{"../a.png", false},
+		{`..\..\a`, false},
+		{"a/b", false},
+		{`foo\bar.png`, false},
+		{"a\x00b", false},
+		{"foo\tbar.png", false},
+		{"foo\rbar.png", false},
+		// MaxFilenameLength matches the VARCHAR(256) column; longer inputs
+		// that bypass SanitizeFilename's truncation must still fail here.
+		{strings.Repeat("a", MaxFilenameLength+1), false},
+		{strings.Repeat("a", MaxFilenameLength), true},
+	}
+	for _, tc := range cases {
+		assert.Equalf(t, tc.valid, IsValidFilename(tc.name), "input %q", tc.name)
+	}
+}
+
+func TestSanitizeFilename(t *testing.T) {
+	cases := []struct {
+		name string
+		in   string
+		want string
+	}{
+		{"plain name unchanged", "hello.png", "hello.png"},
+		{"preserves spaces and parens", "hello world (1).png", "hello world (1).png"},
+		{"reduces leading dotdot path to basename", "../../a.png", "a.png"},
+		{"handles backslash separators", `..\..\a.exe`, "a.exe"},
+		{"reduces nested path to basename", "a/b/c.png", "c.png"},
+		{"strips null bytes", "foo\x00bar.png", "foobar.png"},
+		{"strips control chars", "foo\tbar\x1f.png", "foobar.png"},
+		{"rejects bare dotdot", "..", ""},
+		{"rejects bare dot", ".", ""},
+		{"rejects empty", "", ""},
+		{"rejects root", "/", ""},
+		{"rejects path ending in separator", "../", ""},
+		{"truncates to max length by runes", strings.Repeat("a", MaxFilenameLength+50), strings.Repeat("a", MaxFilenameLength)},
+		{"NFC-normalizes NFD input", "ガ.txt", "ガ.txt"},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := SanitizeFilename(tc.in)
+			assert.Equal(t, tc.want, got)
+			if got != "" {
+				// SanitizeFilename output must always satisfy IsValidFilename.
+				assert.True(t, IsValidFilename(got), "sanitized output %q must be valid", got)
+			}
+		})
+	}
 }
 
 func TestFileInfoIsImage(t *testing.T) {