1 files changed, 80 insertions, 0 deletions
diff --git a/modules/auth/password/hash/argon2.go b/modules/auth/password/hash/argon2.go
new file mode 100644
index 0000000..0cd6472
--- /dev/null
+++ b/modules/auth/password/hash/argon2.go
@@ -0,0 +1,80 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package hash
+
+import (
+	"encoding/hex"
+	"strings"
+
+	"code.gitea.io/gitea/modules/log"
+
+	"golang.org/x/crypto/argon2"
+)
+
+func init() {
+	MustRegister("argon2", NewArgon2Hasher)
+}
+
+// Argon2Hasher implements PasswordHasher
+// and uses the Argon2 key derivation function, hybrant variant
+type Argon2Hasher struct {
+	time    uint32
+	memory  uint32
+	threads uint8
+	keyLen  uint32
+}
+
+// HashWithSaltBytes a provided password and salt
+func (hasher *Argon2Hasher) HashWithSaltBytes(password string, salt []byte) string {
+	if hasher == nil {
+		return ""
+	}
+	return hex.EncodeToString(argon2.IDKey([]byte(password), salt, hasher.time, hasher.memory, hasher.threads, hasher.keyLen))
+}
+
+// NewArgon2Hasher is a factory method to create an Argon2Hasher
+// The provided config should be either empty or of the form:
+// "<time>$<memory>$<threads>$<keyLen>", where <x> is the string representation
+// of an integer
+func NewArgon2Hasher(config string) *Argon2Hasher {
+	// This default configuration uses the following parameters:
+	// time=2, memory=64*1024, threads=8, keyLen=50.
+	// It will make two passes through the memory, using 64MiB in total.
+	// This matches the original configuration for `argon2` prior to storing hash parameters
+	// in the database.
+	// THESE VALUES MUST NOT BE CHANGED OR BACKWARDS COMPATIBILITY WILL BREAK
+	hasher := &Argon2Hasher{
+		time:    2,
+		memory:  1 << 16,
+		threads: 8,
+		keyLen:  50,
+	}
+
+	if config == "" {
+		return hasher
+	}
+
+	vals := strings.SplitN(config, "$", 4)
+	if len(vals) != 4 {
+		log.Error("invalid argon2 hash spec %s", config)
+		return nil
+	}
+
+	parsed, err := parseUIntParam(vals[0], "time", "argon2", config, nil)
+	hasher.time = uint32(parsed)
+
+	parsed, err = parseUIntParam(vals[1], "memory", "argon2", config, err)
+	hasher.memory = uint32(parsed)
+
+	parsed, err = parseUIntParam(vals[2], "threads", "argon2", config, err)
+	hasher.threads = uint8(parsed)
+
+	parsed, err = parseUIntParam(vals[3], "keyLen", "argon2", config, err)
+	hasher.keyLen = uint32(parsed)
+	if err != nil {
+		return nil
+	}
+
+	return hasher
+}