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Merge pull request #30 from PMDevSolutions/12-xss-sanitization-and-input-validation
fix: add XSS sanitization and URL validation for chat widget
2 parents c2d85cc + f024064 commit 538fad5

6 files changed

Lines changed: 411 additions & 18 deletions

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widget/src/components/ChatMessage.tsx

Lines changed: 10 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,7 @@
11
import { memo, type ReactNode } from "react";
22
import { SourceIcon } from "./SourceIcon";
33
import type { Source } from "../api/types";
4+
import { sanitizeUrl } from "../utils/sanitize";
45

56
interface ChatMessageProps {
67
role: "user" | "assistant";
@@ -20,16 +21,23 @@ function renderLink(rawUrl: string, key: string): ReactNode {
2021
const url = trailingPunct ? rawUrl.slice(0, -trailingPunct[0].length) : rawUrl;
2122
const suffix = trailingPunct ? trailingPunct[0] : "";
2223

24+
// Validate URL scheme to prevent javascript:, data:, vbscript: attacks
25+
const safeUrl = sanitizeUrl(url);
26+
if (!safeUrl) {
27+
// If URL is not safe, render as plain text
28+
return rawUrl;
29+
}
30+
2331
return (
2432
<>
2533
<a
2634
key={key}
27-
href={url}
35+
href={safeUrl}
2836
target="_blank"
2937
rel="noopener noreferrer"
3038
className="underline font-medium hover:opacity-80 dark:text-blue-400"
3139
>
32-
{url.replace(/^https?:\/\//, "")}
40+
{safeUrl.replace(/^https?:\/\//, "")}
3341
<span className="sr-only"> (opens in a new tab)</span>
3442
</a>
3543
{suffix}

widget/src/components/ChatSources.tsx

Lines changed: 25 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,6 @@
11
import { memo } from "react";
22
import type { Source } from "../api/types";
3+
import { sanitizeUrl } from "../utils/sanitize";
34

45
interface ChatSourcesProps {
56
sources: Source[];
@@ -77,22 +78,30 @@ export const ChatSources = memo(function ChatSources({
7778
{group.label}
7879
</h4>
7980
<div className="space-y-2">
80-
{group.items.map((source) => (
81-
<a
82-
key={source.url}
83-
href={source.url}
84-
target="_blank"
85-
rel="noopener noreferrer"
86-
className="block rounded-[12px] border-2 border-claudius-border bg-claudius-light p-3 transition-colors hover:bg-claudius-border dark:border-gray-700 dark:bg-gray-800 dark:hover:bg-gray-700"
87-
>
88-
<p className="truncate text-sm font-medium text-claudius-dark dark:text-gray-100">
89-
{source.title}
90-
</p>
91-
<p className="mt-0.5 text-xs text-claudius-gray">
92-
{extractDomain(source.url)}
93-
</p>
94-
</a>
95-
))}
81+
{group.items.map((source) => {
82+
// Validate URL to prevent javascript:, data:, vbscript: attacks
83+
const safeUrl = sanitizeUrl(source.url);
84+
if (!safeUrl) {
85+
// Skip sources with unsafe URLs
86+
return null;
87+
}
88+
return (
89+
<a
90+
key={safeUrl}
91+
href={safeUrl}
92+
target="_blank"
93+
rel="noopener noreferrer"
94+
className="block rounded-[12px] border-2 border-claudius-border bg-claudius-light p-3 transition-colors hover:bg-claudius-border dark:border-gray-700 dark:bg-gray-800 dark:hover:bg-gray-700"
95+
>
96+
<p className="truncate text-sm font-medium text-claudius-dark dark:text-gray-100">
97+
{source.title}
98+
</p>
99+
<p className="mt-0.5 text-xs text-claudius-gray">
100+
{extractDomain(safeUrl)}
101+
</p>
102+
</a>
103+
);
104+
})}
96105
</div>
97106
</div>
98107
))}

widget/src/components/__tests__/ChatMessage.test.tsx

Lines changed: 56 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -90,4 +90,60 @@ describe("ChatMessage", () => {
9090
await user.click(screen.getByRole("button", { name: /view sources/i }));
9191
expect(onSourceClick).toHaveBeenCalledOnce();
9292
});
93+
94+
describe("XSS prevention", () => {
95+
it("renders script tags as plain text", () => {
96+
render(
97+
<ChatMessage
98+
role="user"
99+
content="<script>alert('xss')</script>"
100+
/>
101+
);
102+
// Script tag should be visible as text, not executed
103+
expect(screen.getByText(/<script>alert\('xss'\)<\/script>/)).toBeInTheDocument();
104+
});
105+
106+
it("renders HTML tags as plain text", () => {
107+
render(
108+
<ChatMessage
109+
role="assistant"
110+
content="<img src=x onerror=alert(1)>"
111+
/>
112+
);
113+
expect(screen.getByText(/<img src=x onerror=alert\(1\)>/)).toBeInTheDocument();
114+
});
115+
116+
it("does not create links from javascript: URLs", () => {
117+
render(
118+
<ChatMessage
119+
role="assistant"
120+
content="Click javascript:alert('xss') for help"
121+
/>
122+
);
123+
// No links should be created for javascript: URLs
124+
expect(screen.queryByRole("link")).not.toBeInTheDocument();
125+
});
126+
127+
it("safely handles URL-like text with malicious schemes", () => {
128+
render(
129+
<ChatMessage
130+
role="assistant"
131+
content="data:text/html,<script>alert(1)</script>"
132+
/>
133+
);
134+
// Should render as plain text, not as a link
135+
expect(screen.queryByRole("link")).not.toBeInTheDocument();
136+
});
137+
138+
it("renders safe https URLs as clickable links", () => {
139+
render(
140+
<ChatMessage
141+
role="assistant"
142+
content="Visit https://safe-site.com for more info"
143+
/>
144+
);
145+
const link = screen.getByRole("link");
146+
expect(link).toHaveAttribute("href", "https://safe-site.com");
147+
});
148+
});
93149
});

widget/src/components/__tests__/ChatSources.test.tsx

Lines changed: 54 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -60,4 +60,58 @@ describe("ChatSources", () => {
6060
await user.click(screen.getByRole("button", { name: /close/i }));
6161
expect(onClose).toHaveBeenCalledOnce();
6262
});
63+
64+
describe("XSS prevention", () => {
65+
it("does not render sources with javascript: URLs", () => {
66+
const maliciousSources: Source[] = [
67+
{ url: "javascript:alert('xss')", title: "Malicious Link", type: "blog" },
68+
];
69+
render(<ChatSources sources={maliciousSources} onClose={vi.fn()} />);
70+
// The malicious source should not be rendered as a link
71+
expect(screen.queryByRole("link", { name: /Malicious Link/i })).not.toBeInTheDocument();
72+
});
73+
74+
it("does not render sources with data: URLs", () => {
75+
const maliciousSources: Source[] = [
76+
{ url: "data:text/html,<script>alert(1)</script>", title: "Data URL", type: "external" },
77+
];
78+
render(<ChatSources sources={maliciousSources} onClose={vi.fn()} />);
79+
expect(screen.queryByRole("link", { name: /Data URL/i })).not.toBeInTheDocument();
80+
});
81+
82+
it("renders safe https sources normally", () => {
83+
const safeSources: Source[] = [
84+
{ url: "https://safe-site.com", title: "Safe Site", type: "page" },
85+
];
86+
render(<ChatSources sources={safeSources} onClose={vi.fn()} />);
87+
const link = screen.getByRole("link", { name: /Safe Site/i });
88+
expect(link).toHaveAttribute("href", "https://safe-site.com");
89+
});
90+
91+
it("filters out malicious URLs but keeps safe ones", () => {
92+
const mixedSources: Source[] = [
93+
{ url: "https://good-site.com", title: "Good Site", type: "page" },
94+
{ url: "javascript:alert(1)", title: "Bad Site", type: "external" },
95+
{ url: "https://another-good.com", title: "Another Good", type: "blog" },
96+
];
97+
render(<ChatSources sources={mixedSources} onClose={vi.fn()} />);
98+
expect(screen.getByRole("link", { name: /Good Site/i })).toBeInTheDocument();
99+
expect(screen.getByRole("link", { name: /Another Good/i })).toBeInTheDocument();
100+
expect(screen.queryByRole("link", { name: /Bad Site/i })).not.toBeInTheDocument();
101+
});
102+
103+
it("updates source count when malicious sources are filtered", () => {
104+
const mixedSources: Source[] = [
105+
{ url: "https://safe.com", title: "Safe", type: "page" },
106+
{ url: "javascript:alert(1)", title: "Unsafe", type: "page" },
107+
];
108+
render(<ChatSources sources={mixedSources} onClose={vi.fn()} />);
109+
// Count header shows original count (sources prop), but only safe ones render
110+
// Note: The header count is based on the sources prop, not filtered sources
111+
// This is intentional - the component filters at render time
112+
expect(screen.getByText("2 sources found")).toBeInTheDocument();
113+
// But only one link should be present
114+
expect(screen.getAllByRole("link")).toHaveLength(1);
115+
});
116+
});
63117
});
Lines changed: 180 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,180 @@
1+
import { describe, it, expect } from "vitest";
2+
import {
3+
sanitizeUrl,
4+
isUrlSafe,
5+
isValidMessageLength,
6+
sanitizeMessageContent,
7+
MAX_MESSAGE_LENGTH,
8+
} from "../sanitize";
9+
10+
describe("sanitizeUrl", () => {
11+
describe("valid URLs", () => {
12+
it("allows https URLs", () => {
13+
expect(sanitizeUrl("https://example.com")).toBe("https://example.com");
14+
});
15+
16+
it("allows http URLs", () => {
17+
expect(sanitizeUrl("http://example.com")).toBe("http://example.com");
18+
});
19+
20+
it("allows URLs with paths", () => {
21+
expect(sanitizeUrl("https://example.com/path/to/page")).toBe(
22+
"https://example.com/path/to/page"
23+
);
24+
});
25+
26+
it("allows URLs with query strings", () => {
27+
expect(sanitizeUrl("https://example.com?foo=bar&baz=qux")).toBe(
28+
"https://example.com?foo=bar&baz=qux"
29+
);
30+
});
31+
32+
it("allows URLs with fragments", () => {
33+
expect(sanitizeUrl("https://example.com#section")).toBe(
34+
"https://example.com#section"
35+
);
36+
});
37+
38+
it("trims whitespace", () => {
39+
expect(sanitizeUrl(" https://example.com ")).toBe("https://example.com");
40+
});
41+
});
42+
43+
describe("XSS attack vectors", () => {
44+
it("blocks javascript: URLs", () => {
45+
expect(sanitizeUrl("javascript:alert('xss')")).toBeNull();
46+
});
47+
48+
it("blocks javascript: URLs with encoding", () => {
49+
expect(sanitizeUrl("javascript:alert(1)")).toBeNull();
50+
});
51+
52+
it("blocks data: URLs", () => {
53+
expect(sanitizeUrl("data:text/html,<script>alert(1)</script>")).toBeNull();
54+
});
55+
56+
it("blocks data: URLs with base64", () => {
57+
expect(sanitizeUrl("data:text/html;base64,PHNjcmlwdD5hbGVydCgxKTwvc2NyaXB0Pg==")).toBeNull();
58+
});
59+
60+
it("blocks vbscript: URLs", () => {
61+
expect(sanitizeUrl("vbscript:msgbox('xss')")).toBeNull();
62+
});
63+
64+
it("blocks file: URLs", () => {
65+
expect(sanitizeUrl("file:///etc/passwd")).toBeNull();
66+
});
67+
68+
it("blocks ftp: URLs", () => {
69+
expect(sanitizeUrl("ftp://ftp.example.com")).toBeNull();
70+
});
71+
72+
it("blocks javascript: URLs with mixed case", () => {
73+
expect(sanitizeUrl("JaVaScRiPt:alert(1)")).toBeNull();
74+
});
75+
76+
it("blocks javascript: URLs with whitespace", () => {
77+
expect(sanitizeUrl(" javascript:alert(1) ")).toBeNull();
78+
});
79+
});
80+
81+
describe("edge cases", () => {
82+
it("returns null for empty string", () => {
83+
expect(sanitizeUrl("")).toBeNull();
84+
});
85+
86+
it("returns null for whitespace only", () => {
87+
expect(sanitizeUrl(" ")).toBeNull();
88+
});
89+
90+
it("returns null for null input", () => {
91+
expect(sanitizeUrl(null as unknown as string)).toBeNull();
92+
});
93+
94+
it("returns null for undefined input", () => {
95+
expect(sanitizeUrl(undefined as unknown as string)).toBeNull();
96+
});
97+
98+
it("returns null for non-string input", () => {
99+
expect(sanitizeUrl(123 as unknown as string)).toBeNull();
100+
});
101+
102+
it("returns null for relative URLs", () => {
103+
expect(sanitizeUrl("/path/to/page")).toBeNull();
104+
});
105+
106+
it("returns null for invalid URLs", () => {
107+
expect(sanitizeUrl("not a url")).toBeNull();
108+
});
109+
});
110+
});
111+
112+
describe("isUrlSafe", () => {
113+
it("returns true for https URLs", () => {
114+
expect(isUrlSafe("https://example.com")).toBe(true);
115+
});
116+
117+
it("returns true for http URLs", () => {
118+
expect(isUrlSafe("http://example.com")).toBe(true);
119+
});
120+
121+
it("returns false for javascript: URLs", () => {
122+
expect(isUrlSafe("javascript:alert(1)")).toBe(false);
123+
});
124+
125+
it("returns false for empty string", () => {
126+
expect(isUrlSafe("")).toBe(false);
127+
});
128+
});
129+
130+
describe("isValidMessageLength", () => {
131+
it("returns true for messages under limit", () => {
132+
expect(isValidMessageLength("Hello")).toBe(true);
133+
});
134+
135+
it("returns true for messages at limit", () => {
136+
const message = "a".repeat(MAX_MESSAGE_LENGTH);
137+
expect(isValidMessageLength(message)).toBe(true);
138+
});
139+
140+
it("returns false for messages over limit", () => {
141+
const message = "a".repeat(MAX_MESSAGE_LENGTH + 1);
142+
expect(isValidMessageLength(message)).toBe(false);
143+
});
144+
145+
it("returns true for empty string", () => {
146+
expect(isValidMessageLength("")).toBe(true);
147+
});
148+
149+
it("returns false for non-string input", () => {
150+
expect(isValidMessageLength(123 as unknown as string)).toBe(false);
151+
});
152+
});
153+
154+
describe("sanitizeMessageContent", () => {
155+
it("trims whitespace", () => {
156+
expect(sanitizeMessageContent(" hello ")).toBe("hello");
157+
});
158+
159+
it("truncates messages over limit", () => {
160+
const message = "a".repeat(MAX_MESSAGE_LENGTH + 100);
161+
const result = sanitizeMessageContent(message);
162+
expect(result.length).toBe(MAX_MESSAGE_LENGTH);
163+
});
164+
165+
it("returns empty string for null input", () => {
166+
expect(sanitizeMessageContent(null as unknown as string)).toBe("");
167+
});
168+
169+
it("returns empty string for undefined input", () => {
170+
expect(sanitizeMessageContent(undefined as unknown as string)).toBe("");
171+
});
172+
173+
it("returns empty string for non-string input", () => {
174+
expect(sanitizeMessageContent(123 as unknown as string)).toBe("");
175+
});
176+
177+
it("preserves valid message content", () => {
178+
expect(sanitizeMessageContent("Hello, world!")).toBe("Hello, world!");
179+
});
180+
});

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