fix(security): use constant-time comparison for Convex API secret

commit: c31e89e21ca58dcf6b6bc8989c8dfd737d8640a4
author: Kit · 8mo ago · 2026-02-16 11:01 UTC
parent: 1a6a567
signature: SSH UnverifiedSHA256:H91DFuEG4jpk5edzLA4aUKkpv4zv9Q339ipRmkph6Tk The key is unknown

1 file · +22 -1

M src/convex/http.ts +22 -1


@@ -5,6 +5,23 @@ import type { Id } from './_generated/dataModel';
5	5
6	6		const http = httpRouter();
7	7
	8	+	// Constant-time string comparison to prevent timing attacks
	9	+	function constantTimeCompare(a: string, b: string): boolean {
	10	+	if (a.length !== b.length) {
	11	+	// Still do work to avoid leaking length via timing
	12	+	let result = a.length ^ b.length;
	13	+	for (let i = 0; i < a.length; i++) {
	14	+	result \|= a.charCodeAt(i) ^ a.charCodeAt(i);
	15	+	}
	16	+	return result === 0; // always false when lengths differ
	17	+	}
	18	+	let result = 0;
	19	+	for (let i = 0; i < a.length; i++) {
	20	+	result \|= a.charCodeAt(i) ^ b.charCodeAt(i);
	21	+	}
	22	+	return result === 0;
	23	+	}
	24	+
8	25		// Validate the secret header for server-to-server calls
9	26		function validateSecret(request: Request): boolean {
10	27		const secret = request.headers.get('X-Convex-Secret');

@@ -15,7 +32,11 @@ function validateSecret(request: Request): boolean {
15	32		return false;
16	33		}
17	34
18		-	return secret === expectedSecret;
	35	+	if (!secret) {
	36	+	return false;
	37	+	}
	38	+
	39	+	return constantTimeCompare(secret, expectedSecret);
19	40		}
20	41
21	42		// Generic error response


@@ -5,6 +5,23 @@ import type { Id } from './_generated/dataModel';
5			5
6		const http = httpRouter();	6		const http = httpRouter();
7			7
			8	+	// Constant-time string comparison to prevent timing attacks
			9	+	function constantTimeCompare(a: string, b: string): boolean {
			10	+	if (a.length !== b.length) {
			11	+	// Still do work to avoid leaking length via timing
			12	+	let result = a.length ^ b.length;
			13	+	for (let i = 0; i < a.length; i++) {
			14	+	result \|= a.charCodeAt(i) ^ a.charCodeAt(i);
			15	+	}
			16	+	return result === 0; // always false when lengths differ
			17	+	}
			18	+	let result = 0;
			19	+	for (let i = 0; i < a.length; i++) {
			20	+	result \|= a.charCodeAt(i) ^ b.charCodeAt(i);
			21	+	}
			22	+	return result === 0;
			23	+	}
			24	+
8		// Validate the secret header for server-to-server calls	25		// Validate the secret header for server-to-server calls
9		function validateSecret(request: Request): boolean {	26		function validateSecret(request: Request): boolean {
10		const secret = request.headers.get('X-Convex-Secret');	27		const secret = request.headers.get('X-Convex-Secret');

@@ -15,7 +32,11 @@ function validateSecret(request: Request): boolean {
15		return false;	32		return false;
16		}	33		}
17			34
18	-	return secret === expectedSecret;	35	+	if (!secret) {
			36	+	return false;
			37	+	}
			38	+
			39	+	return constantTimeCompare(secret, expectedSecret);
19		}	40		}
20			41
21		// Generic error response	42		// Generic error response