From 4f5a821e931be3b3794d147a6ac4e1ca400b319d Mon Sep 17 00:00:00 2001
From: Stephen Lombardo <sjlombardo@zetetic.net>
Date: Tue, 28 May 2019 15:40:59 -0400
Subject: [PATCH] do not attempt to lock the database as it will fail if the
 first page is invalid

---
 src/crypto_impl.c             | 10 +---------
 test/sqlcipher-integrity.test | 21 ---------------------
 2 files changed, 1 insertion(+), 30 deletions(-)

diff --git a/src/crypto_impl.c b/src/crypto_impl.c
index d3a1f1e..993531b 100644
--- a/src/crypto_impl.c
+++ b/src/crypto_impl.c
@@ -1256,7 +1256,7 @@ cleanup:
 
 int sqlcipher_codec_ctx_integrity_check(codec_ctx *ctx, Parse *pParse, char *column) {
   Pgno page = 1;
-  int i, trans_rc, rc = 0;
+  int i, rc = 0;
   char *result;
   unsigned char *hmac_out = NULL;
   sqlite3_file *fd = sqlite3PagerFile(ctx->pBt->pBt->pPager);
@@ -1284,13 +1284,6 @@ int sqlcipher_codec_ctx_integrity_check(codec_ctx *ctx, Parse *pParse, char *col
     goto cleanup;
   }
 
-  /* establish an exclusive lock on the database */
-  if((trans_rc = sqlite3BtreeBeginTrans(ctx->pBt, 2, 0)) != SQLITE_OK) {
-    sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, "unable to lock database", P4_TRANSIENT);
-    sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
-    goto cleanup;
-  }
-
   sqlite3OsFileSize(fd, &file_sz);
   hmac_out = sqlcipher_malloc(ctx->hmac_sz);
 
@@ -1330,7 +1323,6 @@ int sqlcipher_codec_ctx_integrity_check(codec_ctx *ctx, Parse *pParse, char *col
   }
 
 cleanup:
-  if(trans_rc == SQLITE_OK) sqlite3BtreeRollback(ctx->pBt, SQLITE_OK, 0);
   if(hmac_out != NULL) sqlcipher_free(hmac_out, ctx->hmac_sz);
   return SQLITE_OK;
 }
diff --git a/test/sqlcipher-integrity.test b/test/sqlcipher-integrity.test
index ec6856b..098c162 100644
--- a/test/sqlcipher-integrity.test
+++ b/test/sqlcipher-integrity.test
@@ -308,25 +308,4 @@ do_test integrity-check-plaintext-header {
 } {{} 1 {{HMAC verification failed for page 1} {HMAC verification failed for page 2}}}
 file delete -force test.db
 
-# verify database locking for cipher_integrity_check
-do_test integrity-check-locking {
-  sqlite_orig db test.db
-  sqlite_orig db2 test.db
-
-  execsql {
-    PRAGMA key = 'test';
-    CREATE TABLE t1(a,b);
-    BEGIN EXCLUSIVE;
-    INSERT INTO t1(a,b) VALUES (1,2);
-  }
-
-  execsql {
-    PRAGMA key = 'test';
-    PRAGMA cipher_integrity_check;
-  } db2
-} {{unable to lock database}}
-sqlite_orig db test.db
-sqlite_orig db2 test.db
-file delete -force test.db
-
 finish_test