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-rw-r--r--src/wrap/sqlite/codecext.cpp261
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diff --git a/src/wrap/sqlite/codecext.cpp b/src/wrap/sqlite/codecext.cpp
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+/*
+ * SQLite3 encryption extention codec
+ * (C) 2010 Olivier de Gaalon
+ *
+ * Distributed under the terms of the Botan license
+ */
+
+#ifndef SQLITE_OMIT_DISKIO
+#ifdef SQLITE_HAS_CODEC
+
+#include "codec.h"
+#include "sqlite3.h"
+
+// Required to implement, called from pragma.c, guessing that "see" is related to the
+// "SQLite Encryption Extension" (the semi-official, for-pay, encryption codec)
+extern "C"
+void sqlite3_activate_see(const char *info) { }
+
+// Free the encryption codec, called from pager.c (address passed in sqlite3PagerSetCodec)
+extern "C"
+void sqlite3PagerFreeCodec(void *pCodec)
+{
+ if (pCodec)
+ delete (Codec*) pCodec;
+}
+
+// Report the page size to the codec, called from pager.c (address passed in sqlite3PagerSetCodec)
+extern "C"
+void sqlite3CodecSizeChange(void *pCodec, int pageSize, int nReserve)
+{
+ Codec* codec = (Codec*) pCodec;
+ codec->SetPageSize(pageSize);
+}
+
+// Encrypt/Decrypt functionality, called by pager.c
+extern "C"
+void* sqlite3Codec(void* pCodec, void* data, Pgno nPageNum, int nMode)
+{
+ if (pCodec == NULL) //Db not encrypted
+ return data;
+
+ Codec* codec = (Codec*) pCodec;
+
+ try
+ {
+ switch(nMode)
+ {
+ case 0: // Undo a "case 7" journal file encryption
+ case 2: // Reload a page
+ case 3: // Load a page
+ if (codec->HasReadKey())
+ codec->Decrypt(nPageNum, (unsigned char*) data);
+ break;
+ case 6: // Encrypt a page for the main database file
+ if (codec->HasWriteKey())
+ data = codec->Encrypt(nPageNum, (unsigned char*) data, true);
+ break;
+ case 7: // Encrypt a page for the journal file
+ /*
+ *Under normal circumstances, the readkey is the same as the writekey. However,
+ *when the database is being rekeyed, the readkey is not the same as the writekey.
+ *(The writekey is the "destination key" for the rekey operation and the readkey
+ *is the key the db is currently encrypted with)
+ *Therefore, for case 7, when the rollback is being written, always encrypt using
+ *the database's readkey, which is guaranteed to be the same key that was used to
+ *read and write the original data.
+ */
+ if (codec->HasReadKey())
+ data = codec->Encrypt(nPageNum, (unsigned char*) data, false);
+ break;
+ }
+ }
+ catch(Botan::Exception e)
+ {
+ sqlite3Error((sqlite3*)codec->GetDB(), SQLITE_ERROR, "Botan Error: %s", e.what());
+ }
+
+ return data;
+}
+
+//These functions are defined in pager.c
+extern "C" void* sqlite3PagerGetCodec(Pager *pPager);
+extern "C" void sqlite3PagerSetCodec(
+ Pager *pPager,
+ void *(*xCodec)(void*,void*,Pgno,int),
+ void (*xCodecSizeChng)(void*,int,int),
+ void (*xCodecFree)(void*),
+ void *pCodec
+);
+
+
+extern "C"
+int sqlite3CodecAttach(sqlite3* db, int nDb, const void* zKey, int nKey)
+{
+ try {
+ if (zKey == NULL || nKey <= 0)
+ {
+ // No key specified, could mean either use the main db's encryption or no encryption
+ if (nDb != 0 && nKey < 0)
+ {
+ //Is an attached database, therefore use the key of main database, if main database is encrypted
+ Codec* mainCodec = (Codec*) sqlite3PagerGetCodec(sqlite3BtreePager(db->aDb[0].pBt));
+ if (mainCodec != NULL)
+ {
+ Codec* codec = new Codec(*mainCodec, db);
+ sqlite3PagerSetCodec(sqlite3BtreePager(db->aDb[nDb].pBt),
+ sqlite3Codec,
+ sqlite3CodecSizeChange,
+ sqlite3PagerFreeCodec, codec);
+ }
+ }
+ }
+ else
+ {
+ // Key specified, setup encryption key for database
+ Codec* codec = new Codec(db);
+ codec->GenerateWriteKey((const char*) zKey, nKey);
+ codec->SetReadIsWrite();
+ sqlite3PagerSetCodec(sqlite3BtreePager(db->aDb[nDb].pBt),
+ sqlite3Codec,
+ sqlite3CodecSizeChange,
+ sqlite3PagerFreeCodec, codec);
+ }
+ }
+ catch(Botan::Exception e) {
+ sqlite3Error(db, SQLITE_ERROR, "Botan Error: %s", e.what());
+ return SQLITE_ERROR;
+ }
+ return SQLITE_OK;
+}
+
+extern "C"
+void sqlite3CodecGetKey(sqlite3* db, int nDb, void** zKey, int* nKey)
+{
+ // The unencrypted password is not stored for security reasons
+ // therefore always return NULL
+ *zKey = NULL;
+ *nKey = -1;
+}
+
+extern "C"
+int sqlite3_key(sqlite3 *db, const void *zKey, int nKey)
+{
+ // The key is only set for the main database, not the temp database
+ return sqlite3CodecAttach(db, 0, zKey, nKey);
+}
+
+extern "C"
+int sqlite3_rekey(sqlite3 *db, const void *zKey, int nKey)
+{
+ // Changes the encryption key for an existing database.
+ int rc = SQLITE_ERROR;
+ Btree* pbt = db->aDb[0].pBt;
+ Pager* pPager = sqlite3BtreePager(pbt);
+ Codec* codec = (Codec*) sqlite3PagerGetCodec(pPager);
+
+ if ((zKey == NULL || nKey == 0) && codec == NULL)
+ {
+ // Database not encrypted and key not specified. Do nothing
+ return SQLITE_OK;
+ }
+
+ if (codec == NULL)
+ {
+ // Database not encrypted, but key specified. Encrypt database
+ try {
+ codec = new Codec(db);
+ codec->GenerateWriteKey((const char*) zKey, nKey);
+ } catch (Botan::Exception e) {
+ sqlite3Error(db, SQLITE_ERROR, "Botan Error %s", e.what());
+ return SQLITE_ERROR;
+ }
+ sqlite3PagerSetCodec(pPager, sqlite3Codec, sqlite3CodecSizeChange, sqlite3PagerFreeCodec, codec);
+ }
+ else if (zKey == NULL || nKey == 0)
+ {
+ // Database encrypted, but key not specified. Decrypt database
+ // Keep read key, drop write key
+ codec->DropWriteKey();
+ }
+ else
+ {
+ // Database encrypted and key specified. Re-encrypt database with new key
+ // Keep read key, change write key to new key
+ try {
+ codec->GenerateWriteKey((const char*) zKey, nKey);
+ } catch (Botan::Exception e) {
+ sqlite3Error(db, SQLITE_ERROR, "Botan Error %s", e.what());
+ return SQLITE_ERROR;
+ }
+ }
+
+ // Start transaction
+ rc = sqlite3BtreeBeginTrans(pbt, 1);
+ if (rc == SQLITE_OK)
+ {
+ // Rewrite all pages using the new encryption key (if specified)
+ int nPageCount = -1;
+ int rc = sqlite3PagerPagecount(pPager, &nPageCount);
+ Pgno nPage = (Pgno) nPageCount;
+ int pageSize = sqlite3BtreeGetPageSize(pbt);
+ //Can't use SQLite3 macro here since pager is forward declared...sigh
+ Pgno nSkip = CODEC_PAGER_MJ_PGNO(pageSize);
+ DbPage *pPage;
+
+ for (Pgno n = 1; rc == SQLITE_OK && n <= nPage; n++)
+ {
+ if (n == nSkip)
+ continue;
+
+ rc = sqlite3PagerGet(pPager, n, &pPage);
+
+ if (!rc)
+ {
+ rc = sqlite3PagerWrite(pPage);
+ sqlite3PagerUnref(pPage);
+ }
+ else
+ sqlite3Error(db, SQLITE_ERROR, "%s", "Error while rekeying database page. Transaction Canceled.");
+ }
+ }
+ else
+ sqlite3Error(db, SQLITE_ERROR, "%s", "Error beginning rekey transaction. Make sure that the current encryption key is correct.");
+
+ if (rc == SQLITE_OK)
+ {
+ // All good, commit
+ rc = sqlite3BtreeCommit(pbt);
+
+ if (rc == SQLITE_OK)
+ {
+ //Database rekeyed and committed successfully, update read key
+ if (codec->HasWriteKey())
+ codec->SetReadIsWrite();
+ else //No write key == no longer encrypted
+ sqlite3PagerSetCodec(pPager, NULL, NULL, NULL, NULL);
+ }
+ else
+ {
+ //FIXME: can't trigger this, not sure if rollback is needed, reference implementation didn't rollback
+ sqlite3Error(db, SQLITE_ERROR, "%s", "Could not commit rekey transaction.");
+ }
+ }
+ else
+ {
+ // Rollback, rekey failed
+ sqlite3BtreeRollback(pbt);
+
+ // go back to read key
+ if (codec->HasReadKey())
+ codec->SetWriteIsRead();
+ else //Database wasn't encrypted to start with
+ sqlite3PagerSetCodec(pPager, NULL, NULL, NULL, NULL);
+ }
+
+ return rc;
+}
+
+#endif // SQLITE_HAS_CODEC
+
+#endif // SQLITE_OMIT_DISKIO
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