Adjustment to ltc crypto provider and cipher_add_random

src/crypto.c

@@ -91,7 +91,7 @@ int sqlcipher_codec_pragma(sqlite3* db, int iDb, Parse *pParse, const char *zLef
 
   if( sqlite3StrICmp(zLeft, "cipher_add_random")==0 && zRight ){
     if(ctx) {
-      char *add_random_status = sqlite3_mprintf("%d", sqlcipher_codec_add_random(ctx, zRight));
+      char *add_random_status = sqlite3_mprintf("%d", sqlcipher_codec_add_random(ctx, zRight, sqlite3Strlen30(zRight)));
       codec_vdbe_return_static_string(pParse, "cipher_add_random", add_random_status);
       sqlite3_free(add_random_status);
     }

src/crypto.h

@@ -213,7 +213,7 @@ int sqlcipher_codec_ctx_get_flag(codec_ctx *ctx, unsigned int flag, int for_ctx)
 
 const char* sqlcipher_codec_get_cipher_provider(codec_ctx *ctx);
 int sqlcipher_codec_ctx_migrate(codec_ctx *ctx);
-int sqlcipher_codec_add_random(codec_ctx *ctx, const char *data);
+int sqlcipher_codec_add_random(codec_ctx *ctx, const char *data, int random_sz);
 #endif
 #endif
 /* END SQLCIPHER */

src/crypto_impl.c

@@ -1124,20 +1124,23 @@ int sqlcipher_codec_ctx_migrate(codec_ctx *ctx) {
   return rc;
 }
 
-int sqlcipher_codec_add_random(codec_ctx *ctx, const char *zRight){
-  int random_sz = strlen(zRight);
+int sqlcipher_codec_add_random(codec_ctx *ctx, const char *zRight, int random_sz){
   const char *suffix = &zRight[random_sz-1];
-  if (sqlite3StrNICmp((const char *)zRight ,"x'", 2) == 0 && sqlite3StrNICmp(suffix, "'", 1) == 0) {
+  int n = random_sz - 3; /* adjust for leading x' and tailing ' */
+  if (n > 0 &&
+      sqlite3StrNICmp((const char *)zRight ,"x'", 2) == 0 &&
+      sqlite3StrNICmp(suffix, "'", 1) == 0 &&
+      n % 2 == 0) {
     int rc = 0;
+    int buffer_sz = n / 2;
     unsigned char *random;
-    int n = random_sz - 3; /* adjust for leading x' and tailing ' */
     const unsigned char *z = (const unsigned char *)zRight + 2; /* adjust lead offset of x' */
     CODEC_TRACE(("sqlcipher_codec_add_random: using raw random blob from hex\n"));
-    random = sqlcipher_malloc(n);
-    memset(random, 0, n);
+    random = sqlcipher_malloc(buffer_sz);
+    memset(random, 0, buffer_sz);
     cipher_hex2bin(z, n, random);
-    rc = ctx->read_ctx->provider->add_random(ctx->read_ctx->provider_ctx, random, n);
-    sqlcipher_free(random, n);
+    rc = ctx->read_ctx->provider->add_random(ctx->read_ctx->provider_ctx, random, buffer_sz);
+    sqlcipher_free(random, buffer_sz);
     return rc;
   }
   return SQLITE_ERROR;

src/crypto_libtomcrypt.c

@@ -35,8 +35,8 @@
 #include "sqlcipher.h"
 #include <tomcrypt.h>
 
+#define FORTUNA_MAX_SZ 32
 static prng_state prng;
-static unsigned int random_block_sz = 32;
 static unsigned int ltc_init = 0;
 static unsigned int ltc_ref_count = 0;
 static sqlite3_mutex* ltc_rand_mutex = NULL;
@@ -44,7 +44,7 @@ static sqlite3_mutex* ltc_rand_mutex = NULL;
 static int sqlcipher_ltc_add_random(void *ctx, void *buffer, int length) {
   int rc = 0;
   int data_to_read = length;
-  int block_sz = data_to_read < random_block_sz ? data_to_read : random_block_sz;
+  int block_sz = data_to_read < FORTUNA_MAX_SZ ? data_to_read : FORTUNA_MAX_SZ;
   const unsigned char * data = (const unsigned char *)buffer;
 #ifndef SQLCIPHER_LTC_NO_MUTEX_RAND
   sqlite3_mutex_enter(ltc_rand_mutex);
@@ -56,10 +56,8 @@ static int sqlcipher_ltc_add_random(void *ctx, void *buffer, int length) {
         break;
       }
       data_to_read -= block_sz;
-      if(data_to_read > 0){
-        block_sz = data_to_read < random_block_sz ? data_to_read : random_block_sz;
-        data += block_sz;
-      }
+      data += block_sz;
+      block_sz = data_to_read < FORTUNA_MAX_SZ ? data_to_read : FORTUNA_MAX_SZ;
     }
     fortuna_ready(&prng);
 #ifndef SQLCIPHER_LTC_NO_MUTEX_RAND
@@ -69,42 +67,56 @@ static int sqlcipher_ltc_add_random(void *ctx, void *buffer, int length) {
 }
 
 static int sqlcipher_ltc_activate(void *ctx) {
-  int random_buffer_sz = sizeof(char) * 32;
-  unsigned char *random_buffer = sqlcipher_malloc(random_buffer_sz);
-  sqlcipher_memset(random_buffer, 0, random_buffer_sz);
-
+  unsigned char random_buffer[FORTUNA_MAX_SZ];
+#ifndef SQLCIPHER_LTC_NO_MUTEX_RAND
+  if(ltc_rand_mutex == NULL){
+    ltc_rand_mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+  }
+  sqlite3_mutex_enter(ltc_rand_mutex);
+#endif
+  sqlcipher_memset(random_buffer, 0, FORTUNA_MAX_SZ);
   if(ltc_init == 0) {
     if(register_prng(&fortuna_desc) != CRYPT_OK) return SQLITE_ERROR;
     if(register_cipher(&rijndael_desc) != CRYPT_OK) return SQLITE_ERROR;
     if(register_hash(&sha1_desc) != CRYPT_OK) return SQLITE_ERROR;
-#ifndef SQLCIPHER_LTC_NO_MUTEX_RAND
-    if(ltc_rand_mutex == NULL){
-      ltc_rand_mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
-    }
-#endif
     if(fortuna_start(&prng) != CRYPT_OK) {
       return SQLITE_ERROR;
     }
     ltc_init = 1;
   }
-  sqlite3_randomness(random_buffer_sz, random_buffer);
-  if(sqlcipher_ltc_add_random(ctx, random_buffer, random_buffer_sz) != SQLITE_OK) {
+  ltc_ref_count++;
+#ifndef SQLCIPHER_TEST
+  sqlite3_randomness(FORTUNA_MAX_SZ, random_buffer);
+#endif
+#ifndef SQLCIPHER_LTC_NO_MUTEX_RAND
+  sqlite3_mutex_leave(ltc_rand_mutex);
+#endif
+  if(sqlcipher_ltc_add_random(ctx, random_buffer, FORTUNA_MAX_SZ) != SQLITE_OK) {
     return SQLITE_ERROR;
   }
-  sqlcipher_free(random_buffer, random_buffer_sz);
-  ltc_ref_count++;
+  sqlcipher_memset(random_buffer, 0, FORTUNA_MAX_SZ);
   return SQLITE_OK;
 }
 
 static int sqlcipher_ltc_deactivate(void *ctx) {
+#ifndef SQLCIPHER_LTC_NO_MUTEX_RAND
+  sqlite3_mutex_enter(ltc_rand_mutex);
+#endif
   ltc_ref_count--;
   if(ltc_ref_count == 0){
     fortuna_done(&prng);
+    sqlcipher_memset((void *)&prng, 0, sizeof(prng));
 #ifndef SQLCIPHER_LTC_NO_MUTEX_RAND
+    sqlite3_mutex_leave(ltc_rand_mutex);
     sqlite3_mutex_free(ltc_rand_mutex);
     ltc_rand_mutex = NULL;
 #endif
   }
+#ifndef SQLCIPHER_LTC_NO_MUTEX_RAND
+  else {
+    sqlite3_mutex_leave(ltc_rand_mutex);
+  }
+#endif    
   return SQLITE_OK;
 }
 

test/crypto.test

@@ -87,6 +87,21 @@ proc if_built_with_commoncrypto {name cmd expected} {
      }
 }
 
+proc cmpFilesChunked {file1 file2 {chunksize 16384}} {
+    set f1 [open $file1]; fconfigure $f1 -translation binary
+    set f2 [open $file2]; fconfigure $f2 -translation binary
+    while {1} {
+        set d1 [read $f1 $chunksize]
+        set d2 [read $f2 $chunksize]
+        set diff [string compare $d1 $d2]
+        if {$diff != 0 || [eof $f1] || [eof $f2]} {
+            close $f1; close $f2
+            return $diff
+        }
+    }
+    return 0
+}
+
 # The database is initially empty.
 # set an hex key create some basic data
 # create table and insert operations should work
@@ -413,9 +428,9 @@ file delete -force test.db
 setup test.db "'testkey'"
 do_test attach-database-with-default-key {
   sqlite_orig db2 test2.db
-
   execsql {
     PRAGMA key = 'testkey';
+    PRAGMA cipher_add_random = "x'deadbaad'";
     CREATE TABLE t2(a,b);
     INSERT INTO t2 VALUES ('test1', 'test2'); 
   } db2
@@ -423,7 +438,7 @@ do_test attach-database-with-default-key {
   catchsql {
     ATTACH 'test.db' AS db;
   } db2
-
+    
 } {1 {file is encrypted or is not a database}}
 db2 close
 file delete -force test.db
@@ -2114,5 +2129,39 @@ db close
 file delete -force test.db
 file delete -force new.db
 
+# Requires SQLCipher to be built with -DSQLCIPHER_TEST
+if_built_with_libtomcrypt verify-random-data-alters-file-content {
+    file delete -force test.db
+    file delete -force test2.db
+    file delete -force test3.db
+    set rc {}
+    
+    sqlite_orig db test.db
+    execsql {
+        PRAGMA key="x'2DD29CA851E7B56E4697B0E1F08507293D761A05CE4D1B628663F411A8086D99'";
+        create table t1(a,b);
+    }
+    db close
+    sqlite_orig db test2.db
+    execsql {
+        PRAGMA key="x'2DD29CA851E7B56E4697B0E1F08507293D761A05CE4D1B628663F411A8086D99'";
+        create table t1(a,b);
+    }
+    db close
+    sqlite_orig db test3.db
+    execsql {
+        PRAGMA key="x'2DD29CA851E7B56E4697B0E1F08507293D761A05CE4D1B628663F411A8086D99'";
+        PRAGMA cipher_add_random = "x'deadbaad'";
+        create table t1(a,b);
+    }
+    db close
+    lappend rc [cmpFilesChunked test.db test2.db]
+    lappend rc [cmpFilesChunked test2.db test3.db]
+} {0 1}
+file delete -force test.db
+file delete -force test2.db
+file delete -force test3.db
+
+
 sqlite3_test_control_pending_byte $old_pending_byte
 finish_test