[sqlite3] Limit max number of memory pages for fuzzing builds.

third_party/sqlite/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//testing/libfuzzer/fuzzer_test.gni")
 
 declare_args() {
   # Controls whether the build should uses the version of sqlite3 library
   # shipped with the system (currently only supported on iOS) or the one
   # shipped with Chromium source.
@@ skipping 119 matching lines @@
       defines += [ "_HAVE_SQLITE_CONFIG_H" ]
     }
 
     if (using_sanitizer) {
       # Limit max length of data blobs and queries for fuzzing builds by 128 MB.
       defines += [
         "SQLITE_MAX_LENGTH=128000000",
         "SQLITE_MAX_SQL_LENGTH=128000000",
         "SQLITE_PRINTF_PRECISION_LIMIT=1280000",
       ]
+
+      # During fuzz testing, valid SQL queries generated by fuzzing engine may
+      # lead to large memory allocations. If that happens, fuzzer reports an
+      # out-of-memory error. However, such errors are not valid bugs.
+      # To avoid hitting those irrelevant OOMs, we limit max number of memory
+      # pages, so fuzzer will not crash when reaching the limit.
+      # Apply this for fuzzing builds only, not for all builds with sanitizers.
+      if (use_libfuzzer || use_afl) {
+        defines += [ "SQLITE_MAX_PAGE_COUNT=16384" ]
+      }
     }
 
     include_dirs = [ "amalgamation" ]
 
     configs -= [ "//build/config/compiler:chromium_code" ]
     configs += [
       "//build/config/compiler:no_chromium_code",
 
       # Must be after no_chromium_code for warning flags to be ordered
       # correctly.
@@ skipping 130 matching lines @@
 fuzzer_test("sqlite3_ossfuzz_fuzzer") {
   # TODO(mmoroz, shess): remove fuzz/ossfuzz.c after next sqlite3 update.
   sources = [
     "fuzz/ossfuzz.c",
   ]
   deps = [
     ":sqlite",
   ]
   dict = "fuzz/sql.dict"
 }