Merge pull request #30 from zkemail/audit/cleanup-documentation

veredise audit fix: Correct and add missing documentation in zkemail.nr

js/src/utils.ts

@@ -8,7 +8,7 @@ export type BoundedVec = {
   len: string;
 };
 /**
- * Transforms a u32 array to a u8 array
+ * Transforms a u32 array to a u8 array in big-endian format
  * @dev sha-utils in zk-email-verify encodes partial hash as u8 array but noir expects u32
  *      transform back to keep upstream code but not have noir worry about transformation
  *
@@ -111,6 +111,7 @@ export function getAddressHeaderSequence(
 
 /**
  * Build a ROM table for allowable email characters
+ * === This function is used to generate a table to reference in Noir code ===
  */
 export function makeEmailAddressCharTable(): string {
   // max value: z = 122
@@ -119,7 +120,7 @@ export function makeEmailAddressCharTable(): string {
   const emailChars =
     "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789.-@";
   const precedingChars = "<: ";
-  const procedingChars = ">\r\n";
+  const proceedingChars = ">\r\n";
   // set valid email chars
   for (let i = 0; i < emailChars.length; i++) {
     table[emailChars.charCodeAt(i)] = 1;
@@ -129,19 +130,14 @@ export function makeEmailAddressCharTable(): string {
     table[precedingChars.charCodeAt(i)] = 2;
   }
   // set valid proceding chars
-  for (let i = 0; i < procedingChars.length; i++) {
-    table[procedingChars.charCodeAt(i)] = 3;
+  for (let i = 0; i < proceedingChars.length; i++) {
+    table[proceedingChars.charCodeAt(i)] = 3;
   }
   let tableStr = `global EMAIL_ADDRESS_CHAR_TABLE: [u8; ${tableLength}] = [\n`;
-  console.log();
   for (let i = 0; i < table.length; i += 10) {
     const end = i + 10 < table.length ? i + 10 : table.length;
     tableStr += `    ${table.slice(i, end).join(", ")},\n`;
   }
   tableStr += "];";
   return tableStr;
 }
-
-// export function computeStandardOutputs(email: Buffer): Promise<[bigint, bigint]> {
-
-// }

lib/src/headers/body_hash.nr

@@ -46,7 +46,8 @@ pub fn get_body_hash<let MAX_HEADER_LENGTH: u32>(
     }
 
 /**
- * Get the body hash from the header without validating the access index
+ * Get the body hash from the header without validating the access index. Does not validate body
+ * hash is valid base64 sequence (https://github.com/noir-lang/noir_base64/blob/4431d08ac661ada9d8d18b115487ff0190b43856/src/lib.nr#L209-L232)
  *
  * @param MAX_HEADER_LENGTH - The maximum length of the email header
  * @param header - The email header as validated in the DKIM signature

lib/src/lib.nr

@@ -16,7 +16,7 @@ global BODY_HASH_BASE64_LENGTH: u32 = 44;
 global CR: u8 = 0x0D;
 global LF: u8 = 0x0A;
 global MAX_DKIM_HEADER_FIELD_LENGTH: u32 = 300; // kinda arbitrary but gives > 100 chars for selector and domain
-global MAX_EMAIL_ADDRESS_LENGTH: u32 = 320;
+global MAX_EMAIL_ADDRESS_LENGTH: u32 = 320; // derived via (https://datatracker.ietf.org/doc/html/rfc5321#section-4.5.3.1.1)
 
 pub struct Sequence {
     index: u32,

lib/src/partial_hash.nr

@@ -74,7 +74,7 @@ global BLOCK_SIZE = 64;
  * @notice can be used for post-partial hashing where client proves part of hash and relies on server to finish
  * 
  *
- * @param N: the maximum length of the message to hash.
+ * @param N: the length of the message to hash.
  *  --- WARNING: N must be divisible by BLOCK_SIZE such that N % BLOCK_SIZE == 0 
  *      otherwise the remaining bytes will not be inputted when computing the initial hash
  * @param msg: the preimage to begin hashing