Store signed group avatars without replacing channel keys

src/chat/chat_core_priv.h

@@ -77,6 +77,7 @@ static inline size_t b64_decode(const char* src, size_t src_len, uint8_t* dst, s
 
 struct ms_props_cbk;    /* member_sync.c */
 struct ms_apply_cbk;    /* member_sync.c */
+struct group_avatar;
 
 struct chat_core_ctx {
     struct UTUN_INSTANCE* inst;
@@ -88,6 +89,7 @@ struct chat_core_ctx {
     /* per-instance sub-module state (was file-scope statics) */
     struct ms_props_cbk* props_cbks;   /* was member_sync.c g_props_cbks */
     struct ms_apply_cbk* apply_cbks;   /* was member_sync.c g_apply_cbks */
+    struct group_avatar* group_avatar;
     uint64_t              media_cache_bytes;   /* was chat_msg.c g_media_cache_bytes */
     void*                 media_backfill_timer;/* was chat_msg.c g_media_startup_backfill_timer */
     int                   media_backfill_ran;  /* was chat_msg.c g_media_startup_backfill_ran */

src/chat/group_avatar.h

@@ -0,0 +1,30 @@
+/* Подписанная аватарка канала: SQLite, максимум 16 КиБ, router-блоки до 4 КиБ.
+ * Все API/callbacks — uasync; данные публикуются только после полной проверки подписи. */
+#ifndef GROUP_AVATAR_H
+#define GROUP_AVATAR_H
+#include <stdint.h>
+#include <stddef.h>
+struct UTUN_INSTANCE;
+#define GROUP_AVATAR_MAX 16384
+#define GROUP_AVATAR_BLOCK 4096
+struct group_avatar_record {
+    uint64_t version;
+    uint16_t size;
+    uint8_t hash[32], signature[64], data[GROUP_AVATAR_MAX];
+};
+int group_avatar_init(struct UTUN_INSTANCE* inst);
+void group_avatar_destroy(struct UTUN_INSTANCE* inst);
+void group_avatar_cancel_group(struct UTUN_INSTANCE* inst, uint64_t group);
+int group_avatar_get(struct UTUN_INSTANCE* inst, uint64_t group, struct group_avatar_record* record);
+/* 1=изменено, 0=прежняя/старая запись; <0 — ошибка. */
+int group_avatar_apply(struct UTUN_INSTANCE* inst, uint64_t group, const struct group_avatar_record* record);
+/* Публикация своей картинки требует приватный Ed25519 ключ канала. size=0 — подписанное удаление. */
+int group_avatar_set(struct UTUN_INSTANCE* inst, uint64_t group, const uint8_t* data, size_t size);
+struct group_avatar_gui_request {
+    struct UTUN_INSTANCE* inst;
+    uint64_t id, group;
+    uint16_t size;
+    uint8_t data[GROUP_AVATAR_MAX];
+};
+void group_avatar_gui_set(void* arg);
+#endif

src/routing_layer/topo_node_sqlite.c

@@ -295,6 +295,10 @@ int topo_node_sqlite_init(sqlite3* db) {
         "  ed25519_pubkey   BLOB NOT NULL,"     // ключ для проверки подписи
         "  ed25519_privkey  BLOB,"              // ключ для создания подписи
         "  signature        BLOB NOT NULL,"     // подпись при создании канал приватным ключом канала channel_id(NUL-terminated) || name(NUL-terminated) || owner_node_id(8 байт, LE uint64) || x25519_pubkey(32 байта) || ed25519_pubkey(32 байта) 
+        "  avatar_version   INTEGER NOT NULL DEFAULT 0,"
+        "  avatar_data      BLOB,"
+        "  avatar_hash      BLOB,"
+        "  avatar_signature BLOB,"
         "  last_read_msg_id INTEGER,"           // для скроллинга чата
         "  last_pos_msg_id  INTEGER,"           // для скроллинга чата
         "  last_msg_at      INTEGER DEFAULT 0,"  // время последнего сообщения (unix timestamp)
@@ -448,9 +452,14 @@ int topo_node_sqlite_channel_put(sqlite3* db, const char* channel_id,
 
     sqlite3_stmt* stmt = NULL;
     if (sqlite3_prepare_v2(db,
-            "INSERT OR REPLACE INTO channels(channel_id, name, owner_node_id,"
+            "INSERT INTO channels(channel_id, name, owner_node_id,"
             " x25519_pubkey, x25519_privkey, ed25519_pubkey, ed25519_privkey, signature)"
-            " VALUES(?,?,?,?,?,?,?,?)", -1, &stmt, NULL) != SQLITE_OK) return -1;
+            " VALUES(?,?,?,?,?,?,?,?) ON CONFLICT(channel_id) DO UPDATE SET"
+            " name=excluded.name,owner_node_id=excluded.owner_node_id,signature=excluded.signature,"
+            " x25519_privkey=COALESCE(excluded.x25519_privkey,channels.x25519_privkey),"
+            " ed25519_privkey=COALESCE(excluded.ed25519_privkey,channels.ed25519_privkey)"
+            " WHERE channels.x25519_pubkey=excluded.x25519_pubkey AND channels.ed25519_pubkey=excluded.ed25519_pubkey",
+            -1, &stmt, NULL) != SQLITE_OK) return -1;
     sqlite3_bind_text(stmt, 1, channel_id, -1, SQLITE_STATIC);
     sqlite3_bind_text(stmt, 2, name, -1, SQLITE_STATIC);
     sqlite3_bind_int64(stmt, 3, (sqlite3_int64)owner_node_id);
@@ -462,6 +471,9 @@ int topo_node_sqlite_channel_put(sqlite3* db, const char* channel_id,
     else sqlite3_bind_null(stmt, 7);
     sqlite3_bind_blob(stmt, 8, signature, 64, SQLITE_STATIC);
     int rc = sqlite3_step(stmt); sqlite3_finalize(stmt);
+    if (rc == SQLITE_DONE && !sqlite3_changes(db)) {
+        DEBUG_WARN(DEBUG_CATEGORY_CHAT, "channel: rejected identity change channel=%s", channel_id); return -1;
+    }
     return rc == SQLITE_DONE ? 0 : -1;
 }