[2609] fix ReDoS vulnerability in email regex (#2824)

Author: MacsDickinson

deno/lib/README.md

@@ -1879,7 +1879,7 @@ You can create a Zod schema for any TypeScript type by using `z.custom()`. This
 
 ```ts
 const px = z.custom<`${number}px`>((val) => {
-  return /^\d+px$/.test(val as string);
+  return typeof val === "string" ? /^\d+px$/.test(val) : false;
 });
 
 type px = z.infer<typeof px>; // `${number}px`

deno/lib/__tests__/string.test.ts

@@ -146,6 +146,7 @@ test("email validations", () => {
     `gbacher0@[IPv6:bc37:4d3f:5048:2e26:37cc:248e:df8e:2f7f:af]`,
     `invalid@[IPv6:5348:4ed3:5d38:67fb:e9b:acd2:c13:192.168.256.1]`,
     `test@.com`,
+    `aaaaaaaaaaaaaaalongemailthatcausesregexDoSvulnerability@test.c`
   ];
   const emailSchema = z.string().email();
 

deno/lib/types.ts

@@ -565,7 +565,7 @@ const uuidRegex =
 // const emailRegex =
 //   /^(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])$/i;
 const emailRegex =
-  /^([A-Z0-9_+-]+\.?)*[A-Z0-9_+-]@([A-Z0-9][A-Z0-9\-]*\.)+[A-Z]{2,}$/i;
+  /^(?!\.)(?!.*\.\.)([A-Z0-9_+-\.]*)[A-Z0-9_+-]@([A-Z0-9][A-Z0-9\-]*\.)+[A-Z]{2,}$/i;
 // const emailRegex =
 //   /^[a-z0-9.!#$%&’*+/=?^_`{|}~-]+@[a-z0-9-]+(?:\.[a-z0-9\-]+)*$/i;
 

src/__tests__/string.test.ts

@@ -145,6 +145,7 @@ test("email validations", () => {
     `gbacher0@[IPv6:bc37:4d3f:5048:2e26:37cc:248e:df8e:2f7f:af]`,
     `invalid@[IPv6:5348:4ed3:5d38:67fb:e9b:acd2:c13:192.168.256.1]`,
     `test@.com`,
+    `aaaaaaaaaaaaaaalongemailthatcausesregexDoSvulnerability@test.c`
   ];
   const emailSchema = z.string().email();
 

src/types.ts

@@ -565,7 +565,7 @@ const uuidRegex =
 // const emailRegex =
 //   /^(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])$/i;
 const emailRegex =
-  /^([A-Z0-9_+-]+\.?)*[A-Z0-9_+-]@([A-Z0-9][A-Z0-9\-]*\.)+[A-Z]{2,}$/i;
+  /^(?!\.)(?!.*\.\.)([A-Z0-9_+-\.]*)[A-Z0-9_+-]@([A-Z0-9][A-Z0-9\-]*\.)+[A-Z]{2,}$/i;
 // const emailRegex =
 //   /^[a-z0-9.!#$%&’*+/=?^_`{|}~-]+@[a-z0-9-]+(?:\.[a-z0-9\-]+)*$/i;