Commit 37db93e4260dfcb90ac1553cf096a35ada1825ca | zig

author	Rob Napier <rob@neverwood.org> 2020-09-12 15:02:00-04:00
committer	Rob Napier <rob@neverwood.org> 2020-09-12 15:03:42-04:00
log	37db93e4260dfcb90ac1553cf096a35ada1825ca
tree	312b8490c7709d7c163904c7756f225a561c0c21
parent	c2b02d01d5c0bb684565d5b23b34022b752e9507

Review comments from pbkdf2.zig

Move block definitions inside while loop.
Use usize for offset. (This still crashes on overflow)
Remove unneeded slice syntax.
Add slow test for Very large dkLen

1 files changed, 28 insertions(+), 6 deletions(-)

lib
- std
  - crypto
    pbkdf2.zig

lib/std/crypto/pbkdf2.zig+28-6

 @@ -95,11 +95,10 @@ pub fn pbkdf2(derivedKey: []u8, password: []const u8, salt: []const u8, rounds:
     //
     //            DK = T_1 || T_2 ||  ...  || T_l<0..r-1>
-    var prevBlock: [hLen]u8 = undefined;
-    var newBlock: [hLen]u8 = undefined;
     var block: u32 = 0; // Spec limits to u32
     while (block < l) : (block += 1) {
+        var prevBlock: [hLen]u8 = undefined;
+        var newBlock: [hLen]u8 = undefined;
         // U_1 = PRF (P, S || INT (i))
         const blockIndex = mem.toBytes(mem.nativeToBig(u32, block + 1)); // Block index starts at 0001
 @@ -109,15 +108,15 @@ pub fn pbkdf2(derivedKey: []u8, password: []const u8, salt: []const u8, rounds:
         ctx.final(prevBlock[0..]);
         // Choose portion of DK to write into (T_n) and initialize
-        const offset = block * hLen;
+        const offset: usize = block * hLen;
         const blockLen = if (block != l - 1) hLen else r;
         var dkBlock = derivedKey[offset..(offset + blockLen)];
-        mem.copy(u8, dkBlock[0..], prevBlock[0..dkBlock.len]);
+        mem.copy(u8, dkBlock, prevBlock[0..dkBlock.len]);
         var i: u32 = 1;
         while (i < rounds) : (i += 1) {
             // U_c = PRF (P, U_{c-1})
-            Prf.create(newBlock[0..], prevBlock[0..], password);
+            Prf.create(&newBlock, prevBlock[0..], password);
             mem.copy(u8, prevBlock[0..], newBlock[0..]);
             // F (P, S, c, i) = U_1 \xor U_2 \xor ... \xor U_c
 @@ -225,3 +224,26 @@ test "RFC 6070 embedded NUL" {
     htest.assertEqual(expected, derivedKey[0..]);
 }
+test "Very large dkLen" {
+    // These iteration tests are slow so we always skip them. Results have been verified.
+    if (true) {
+        return error.SkipZigTest;
+    }
+    const p = "password";
+    const s = "salt";
+    const c = 1;
+    const dkLen = 1 << 33;
+    var derivedKey = try std.testing.allocator.alloc(u8, dkLen);
+    defer {
+        std.testing.allocator.free(derivedKey);
+    }
+    pbkdf2(derivedKey, p, s, c, crypto.hash.Sha1);
+    const expected = "0c60c80f961f0e71f3a9b524af6012062fe037a6";
+    htest.assertEqual(expected, derivedKey[0..]);
+}