Rename Exercice's Keys as Flags

libfic/flag.go

@@ -0,0 +1,129 @@
+package fic
+
+import (
+	"time"
+
+	"golang.org/x/crypto/blake2b"
+)
+
+
+// Flag represents a flag's challenge, stored as hash.
+type Flag struct {
+	Id         int64  `json:"id"`
+	// IdExercice is the identifier of the underlying challenge
+	IdExercice int64  `json:"idExercice"`
+	// Label is the title of the flag as displayed to players
+	Label      string `json:"label"`
+	// Help is a small piece of text that aims to add useful information like flag format, ...
+	Help       string `json:"help"`
+	// IgnoreCase indicates if the case is sensitive to case or not
+	IgnoreCase bool   `json:"ignorecase"`
+	// Checksum is the expected hashed flag
+	Checksum   []byte `json:"value"`
+}
+
+// GetFlags returns a list of flags comming with the challenge.
+func (e Exercice) GetFlags() ([]Flag, error) {
+	if rows, err := DBQuery("SELECT id_flag, id_exercice, type, help, ignorecase, cksum FROM exercice_flags WHERE id_exercice = ?", e.Id); err != nil {
+		return nil, err
+	} else {
+		defer rows.Close()
+
+		var flags = make([]Flag, 0)
+		for rows.Next() {
+			var k Flag
+			k.IdExercice = e.Id
+
+			if err := rows.Scan(&k.Id, &k.IdExercice, &k.Label, &k.Help, &k.IgnoreCase, &k.Checksum); err != nil {
+				return nil, err
+			}
+			flags = append(flags, k)
+		}
+		if err := rows.Err(); err != nil {
+			return nil, err
+		}
+
+		return flags, nil
+	}
+}
+
+// getHashedFlag calculates the expected checksum for the given raw_value.
+func getHashedFlag(raw_value string) [blake2b.Size]byte {
+	hash := blake2b.Sum512([]byte(raw_value))
+	return hash
+}
+
+// AddRawFlag creates and fills a new struct Flag, from a non-hashed flag, and registers it into the database.
+func (e Exercice) AddRawFlag(name string, help string, ignorecase bool, raw_value string) (Flag, error) {
+	hash := getHashedFlag(raw_value)
+	return e.AddFlag(name, help, ignorecase, hash[:])
+}
+
+// AddFlag creates and fills a new struct Flag, from a hashed flag, and registers it into the database.
+func (e Exercice) AddFlag(name string, help string, ignorecase bool, checksum []byte) (Flag, error) {
+	if res, err := DBExec("INSERT INTO exercice_flags (id_exercice, type, help, ignorecase, cksum) VALUES (?, ?, ?, ?, ?)", e.Id, name, help, ignorecase, checksum); err != nil {
+		return Flag{}, err
+	} else if kid, err := res.LastInsertId(); err != nil {
+		return Flag{}, err
+	} else {
+		return Flag{kid, e.Id, name, help, ignorecase, checksum}, nil
+	}
+}
+
+// Update applies modifications back to the database.
+func (k Flag) Update() (int64, error) {
+	if res, err := DBExec("UPDATE exercice_flags SET id_exercice = ?, type = ?, help = ?, ignorecase = ?, cksum = ? WHERE id_flag = ?", k.IdExercice, k.Label, k.Help, k.IgnoreCase, k.Checksum, k.Id); err != nil {
+		return 0, err
+	} else if nb, err := res.RowsAffected(); err != nil {
+		return 0, err
+	} else {
+		return nb, err
+	}
+}
+
+// Delete the flag from the database.
+func (k Flag) Delete() (int64, error) {
+	if _, err := DBExec("DELETE FROM exercice_files_deps WHERE id_flag = ?", k.Id); err != nil {
+		return 0, err
+	} else if res, err := DBExec("DELETE FROM exercice_flags WHERE id_flag = ?", k.Id); err != nil {
+		return 0, err
+	} else if nb, err := res.RowsAffected(); err != nil {
+		return 0, err
+	} else {
+		return nb, err
+	}
+}
+
+// WipeFlags deletes flags coming with the challenge.
+func (e Exercice) WipeFlags() (int64, error) {
+	if _, err := DBExec("DELETE FROM exercice_files_deps WHERE id_flag IN (SELECT id_flag FROM exercice_flags WHERE id_exercice = ?)", e.Id); err != nil {
+		return 0, err
+	} else if res, err := DBExec("DELETE FROM exercice_flags WHERE id_exercice = ?", e.Id); err != nil {
+		return 0, err
+	} else if nb, err := res.RowsAffected(); err != nil {
+		return 0, err
+	} else {
+		return nb, err
+	}
+}
+
+// Check if the given val is the expected one for this flag.
+func (k Flag) Check(val string) bool {
+	hash := getHashedFlag(val)
+	if len(k.Checksum) != len(hash) {
+		return false
+	}
+
+	for i := range hash {
+		if k.Checksum[i] != hash[i] {
+			return false
+		}
+	}
+
+	return true
+}
+
+// FoundBy registers in the database that the given Team solved the flag.
+func (k Flag) FoundBy(t Team) {
+	DBExec("INSERT INTO flag_found (id_flag, id_team, time) VALUES (?, ?, ?)", k.Id, t.Id, time.Now())
+}