pwhash: Simplify strHash/strVerify APIs

lib/std/crypto/argon2.zig

@@ -578,51 +578,30 @@ const PhcFormatHasher = struct {
 };
 
 /// Options for hashing a password.
-///
-/// Allocator is required for argon2.
-///
-/// Only phc encoding is supported.
 pub const HashOptions = struct {
-    allocator: ?mem.Allocator,
     params: Params,
     mode: Mode = .argon2id,
-    encoding: pwhash.Encoding = .phc,
+    strhash_max_bytes: usize = 128,
 };
 
 /// Compute a hash of a password using the argon2 key derivation function.
 /// The function returns a string that includes all the parameters required for verification.
 pub fn strHash(
+    allocator: mem.Allocator,
     password: []const u8,
-    options: HashOptions,
-    out: []u8,
-) Error![]const u8 {
-    const allocator = options.allocator orelse return Error.AllocatorRequired;
-    switch (options.encoding) {
-        .phc => return PhcFormatHasher.create(
-            allocator,
-            password,
-            options.params,
-            options.mode,
-            out,
-        ),
-        .crypt => return Error.InvalidEncoding,
-    }
+    comptime options: HashOptions,
+) Error![]u8 {
+    var buf: [options.strhash_max_bytes]u8 = undefined;
+    const out = try PhcFormatHasher.create(allocator, password, options.params, options.mode, &buf);
+    return allocator.dupe(u8, out);
 }
 
-/// Options for hash verification.
-///
-/// Allocator is required for argon2.
-pub const VerifyOptions = struct {
-    allocator: ?mem.Allocator,
-};
-
 /// Verify that a previously computed hash is valid for a given password.
 pub fn strVerify(
+    allocator: mem.Allocator,
     str: []const u8,
     password: []const u8,
-    options: VerifyOptions,
 ) Error!void {
-    const allocator = options.allocator orelse return Error.AllocatorRequired;
     return PhcFormatHasher.verify(allocator, str, password);
 }
 
@@ -919,13 +898,14 @@ test "password hash and password verify" {
     const allocator = std.testing.allocator;
     const password = "testpass";
 
-    var buf: [128]u8 = undefined;
     const hash = try strHash(
+        allocator,
         password,
-        .{ .allocator = allocator, .params = .{ .t = 3, .m = 32, .p = 4 } },
-        &buf,
+        .{ .params = .{ .t = 3, .m = 32, .p = 4 } },
     );
-    try strVerify(hash, password, .{ .allocator = allocator });
+    defer allocator.free(hash);
+
+    try strVerify(allocator, hash, password);
 }
 
 test "kdf derived key length" {

lib/std/crypto/bcrypt.zig

@@ -748,12 +748,17 @@ const CryptFormatHasher = struct {
 
 /// Options for hashing a password.
 pub const HashOptions = struct {
-    /// For `bcrypt`, that can be left to `null`.
-    allocator: ?mem.Allocator = null,
     /// Internal bcrypt parameters.
     params: Params,
     /// Encoding to use for the output of the hash function.
     encoding: pwhash.Encoding,
+    /// The maximum length in bytes for a hashed password. If not
+    /// set by the developer, this varies based on encoding.
+    /// `crypt` encoding uses 60 bytes, and `phc` encoding uses
+    /// 120 bytes.
+    ///
+    /// The returned hash may be smaller than the maximum length.
+    strhash_max_bytes: ?usize = null,
 };
 
 /// Compute a hash of a password using 2^rounds_log rounds of the bcrypt key stretching function.
@@ -764,20 +769,25 @@ pub const HashOptions = struct {
 /// IMPORTANT: by design, bcrypt silently truncates passwords to 72 bytes.
 /// If this is an issue for your application, set the `silently_truncate_password` option to `false`.
 pub fn strHash(
+    allocator: mem.Allocator,
     password: []const u8,
-    options: HashOptions,
-    out: []u8,
-) Error![]const u8 {
-    switch (options.encoding) {
-        .phc => return PhcFormatHasher.create(password, options.params, out),
-        .crypt => return CryptFormatHasher.create(password, options.params, out),
-    }
+    comptime options: HashOptions,
+) Error![]u8 {
+    const buf_len = comptime if (options.strhash_max_bytes) |len| len else switch (options.encoding) {
+        .crypt => hash_length,
+        .phc => hash_length * 2,
+    };
+    var buf: [buf_len]u8 = undefined;
+
+    const out = switch (options.encoding) {
+        .phc => try PhcFormatHasher.create(password, options.params, &buf),
+        .crypt => try CryptFormatHasher.create(password, options.params, &buf),
+    };
+    return allocator.dupe(u8, out);
 }
 
 /// Options for hash verification.
 pub const VerifyOptions = struct {
-    /// For `bcrypt`, that can be left to `null`.
-    allocator: ?mem.Allocator = null,
     /// Whether to silently truncate the password to 72 bytes, or pre-hash the password when it is longer.
     silently_truncate_password: bool,
 };
@@ -806,14 +816,15 @@ test "bcrypt codec" {
 }
 
 test "bcrypt crypt format" {
-    var hash_options = HashOptions{
+    const allocator = std.testing.allocator;
+    const hash_options = HashOptions{
         .params = .{ .rounds_log = 5, .silently_truncate_password = false },
         .encoding = .crypt,
     };
-    var verify_options = VerifyOptions{ .silently_truncate_password = false };
+    const verify_options = VerifyOptions{ .silently_truncate_password = false };
 
-    var buf: [hash_length]u8 = undefined;
-    const s = try strHash("password", hash_options, &buf);
+    const s = try strHash(allocator, "password", hash_options);
+    defer allocator.free(s);
 
     try testing.expect(mem.startsWith(u8, s, crypt_format.prefix));
     try strVerify(s, "password", verify_options);
@@ -822,8 +833,7 @@ test "bcrypt crypt format" {
         strVerify(s, "invalid password", verify_options),
     );
 
-    var long_buf: [hash_length]u8 = undefined;
-    var long_s = try strHash("password" ** 100, hash_options, &long_buf);
+    var long_s = try strHash(allocator, "password" ** 100, hash_options);
 
     try testing.expect(mem.startsWith(u8, long_s, crypt_format.prefix));
     try strVerify(long_s, "password" ** 100, verify_options);
@@ -832,28 +842,33 @@ test "bcrypt crypt format" {
         strVerify(long_s, "password" ** 101, verify_options),
     );
 
-    hash_options.params.silently_truncate_password = true;
-    verify_options.silently_truncate_password = true;
-    long_s = try strHash("password" ** 100, hash_options, &long_buf);
-    try strVerify(long_s, "password" ** 101, verify_options);
+    allocator.free(long_s);
+
+    long_s = try strHash(allocator, "password" ** 100, .{
+        .params = .{ .rounds_log = 5, .silently_truncate_password = true },
+        .encoding = .crypt,
+    });
+    defer allocator.free(long_s);
+    try strVerify(long_s, "password" ** 101, .{ .silently_truncate_password = true });
 
     try strVerify(
         "$2b$08$WUQKyBCaKpziCwUXHiMVvu40dYVjkTxtWJlftl0PpjY2BxWSvFIEe",
         "The devil himself",
-        verify_options,
+        .{ .silently_truncate_password = true },
     );
 }
 
 test "bcrypt phc format" {
-    var hash_options = HashOptions{
+    const allocator = std.testing.allocator;
+    const hash_options = HashOptions{
         .params = .{ .rounds_log = 5, .silently_truncate_password = false },
         .encoding = .phc,
     };
-    var verify_options = VerifyOptions{ .silently_truncate_password = false };
+    const verify_options = VerifyOptions{ .silently_truncate_password = false };
     const prefix = "$bcrypt$";
 
-    var buf: [hash_length * 2]u8 = undefined;
-    const s = try strHash("password", hash_options, &buf);
+    const s = try strHash(allocator, "password", hash_options);
+    defer allocator.free(s);
 
     try testing.expect(mem.startsWith(u8, s, prefix));
     try strVerify(s, "password", verify_options);
@@ -862,8 +877,7 @@ test "bcrypt phc format" {
         strVerify(s, "invalid password", verify_options),
     );
 
-    var long_buf: [hash_length * 2]u8 = undefined;
-    var long_s = try strHash("password" ** 100, hash_options, &long_buf);
+    var long_s = try strHash(allocator, "password" ** 100, hash_options);
 
     try testing.expect(mem.startsWith(u8, long_s, prefix));
     try strVerify(long_s, "password" ** 100, verify_options);
@@ -872,10 +886,14 @@ test "bcrypt phc format" {
         strVerify(long_s, "password" ** 101, verify_options),
     );
 
-    hash_options.params.silently_truncate_password = true;
-    verify_options.silently_truncate_password = true;
-    long_s = try strHash("password" ** 100, hash_options, &long_buf);
-    try strVerify(long_s, "password" ** 101, verify_options);
+    allocator.free(long_s);
+
+    long_s = try strHash(allocator, "password" ** 100, .{
+        .params = .{ .rounds_log = 5, .silently_truncate_password = true },
+        .encoding = .crypt,
+    });
+    defer allocator.free(long_s);
+    try strVerify(long_s, "password" ** 101, .{ .silently_truncate_password = true });
 
     try strVerify(
         "$bcrypt$r=5$2NopntlgE2lX3cTwr4qz8A$r3T7iKYQNnY4hAhGjk9RmuyvgrYJZwc",

lib/std/crypto/benchmark.zig

@@ -387,50 +387,95 @@ pub fn benchmarkAes8(comptime Aes: anytype, comptime count: comptime_int) !u64 {
 }
 
 const CryptoPwhash = struct {
-    ty: type,
-    params: *const anyopaque,
     name: []const u8,
+    benchmark: fn (mem.Allocator, comptime comptime_int) anyerror!f64,
 };
 const bcrypt_params = crypto.pwhash.bcrypt.Params{ .rounds_log = 8, .silently_truncate_password = true };
 const pwhashes = [_]CryptoPwhash{
     .{
-        .ty = crypto.pwhash.bcrypt,
-        .params = &bcrypt_params,
         .name = "bcrypt",
+        .benchmark = benchmarkBcryptPwhash,
     },
     .{
-        .ty = crypto.pwhash.scrypt,
-        .params = &crypto.pwhash.scrypt.Params.interactive,
         .name = "scrypt",
+        .benchmark = benchmarkScryptPwhash,
     },
     .{
-        .ty = crypto.pwhash.argon2,
-        .params = &crypto.pwhash.argon2.Params.interactive_2id,
         .name = "argon2",
+        .benchmark = benchmarkArgon2Pwhash,
     },
 };
 
-fn benchmarkPwhash(
+fn benchmarkBcryptPwhash(
+    allocator: mem.Allocator,
+    comptime count: comptime_int,
+) !f64 {
+    const password = "testpass" ** 2;
+    const opts = crypto.pwhash.bcrypt.HashOptions{
+        .params = bcrypt_params,
+        .encoding = .phc,
+        .strhash_max_bytes = 256,
+    };
+
+    var timer = try Timer.start();
+    const start = timer.lap();
+    {
+        var i: usize = 0;
+        while (i < count) : (i += 1) {
+            _ = try crypto.pwhash.bcrypt.strHash(allocator, password, opts);
+        }
+    }
+    const end = timer.read();
+
+    const elapsed_s = @as(f64, @floatFromInt(end - start)) / time.ns_per_s;
+    const throughput = elapsed_s / count;
+
+    return throughput;
+}
+
+fn benchmarkScryptPwhash(
     allocator: mem.Allocator,
-    comptime ty: anytype,
-    comptime params: *const anyopaque,
     comptime count: comptime_int,
 ) !f64 {
     const password = "testpass" ** 2;
-    const opts = ty.HashOptions{
-        .allocator = allocator,
-        .params = @as(*const ty.Params, @ptrCast(@alignCast(params))).*,
+    const opts = crypto.pwhash.scrypt.HashOptions{
+        .params = crypto.pwhash.scrypt.Params.interactive,
         .encoding = .phc,
+        .strhash_max_bytes = 256,
+    };
+
+    var timer = try Timer.start();
+    const start = timer.lap();
+    {
+        var i: usize = 0;
+        while (i < count) : (i += 1) {
+            _ = try crypto.pwhash.scrypt.strHash(allocator, password, opts);
+        }
+    }
+    const end = timer.read();
+
+    const elapsed_s = @as(f64, @floatFromInt(end - start)) / time.ns_per_s;
+    const throughput = elapsed_s / count;
+
+    return throughput;
+}
+
+fn benchmarkArgon2Pwhash(
+    allocator: mem.Allocator,
+    comptime count: comptime_int,
+) !f64 {
+    const password = "testpass" ** 2;
+    const opts = crypto.pwhash.argon2.HashOptions{
+        .params = crypto.pwhash.argon2.Params.interactive_2id,
+        .strhash_max_bytes = 256,
     };
-    var buf: [256]u8 = undefined;
 
     var timer = try Timer.start();
     const start = timer.lap();
     {
         var i: usize = 0;
         while (i < count) : (i += 1) {
-            _ = try ty.strHash(password, opts, &buf);
-            mem.doNotOptimizeAway(&buf);
+            _ = try crypto.pwhash.argon2.strHash(allocator, password, opts);
         }
     }
     const end = timer.read();
@@ -563,7 +608,7 @@ pub fn main() !void {
 
     inline for (pwhashes) |H| {
         if (filter == null or std.mem.indexOf(u8, H.name, filter.?) != null) {
-            const throughput = try benchmarkPwhash(arena_allocator, H.ty, H.params, mode(64));
+            const throughput = try H.benchmark(arena_allocator, mode(64));
             try stdout.print("{s:>17}: {d:10.3} s/ops\n", .{ H.name, throughput });
         }
     }