Check sync words count to be 24; fixes brave/brave-browser#23206

brave · Jun 3, 2022 · 2b3e1ac · 2b3e1ac
1 parent fda3cbb
commit 2b3e1ac
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diff --git a/components/brave_sync/crypto/crypto.cc b/components/brave_sync/crypto/crypto.cc
@@ -8,6 +8,7 @@
 #include <cmath>
 
 #include "base/logging.h"
+#include "base/strings/string_split.h"
 #include "brave/vendor/bat-native-tweetnacl/tweetnacl.h"
 #include "brave/vendor/bip39wally-core-native/include/wally_bip39.h"
 #include "crypto/random.h"
@@ -158,6 +159,17 @@ bool PassphraseToBytes32(const std::string& passphrase,
 }
 
 bool IsPassphraseValid(const std::string& passphrase) {
+  // This check is dedicated for old client to reject sync code from new client
+  // which has time limited code (25 words)
+  std::vector<std::string> words = base::SplitString(
+      passphrase, " ", base::WhitespaceHandling::TRIM_WHITESPACE,
+      base::SplitResult::SPLIT_WANT_NONEMPTY);
+  size_t num_words = words.size();
+  static constexpr size_t kPureWordsCount = 24u;
+  if (num_words != kPureWordsCount) {
+    return false;
+  }
+
   std::vector<uint8_t> bytes;
   return PassphraseToBytes32(passphrase, &bytes);
 }

diff --git a/components/brave_sync/crypto/crypto_unittest.cc b/components/brave_sync/crypto/crypto_unittest.cc
@@ -249,6 +249,8 @@ TEST(CryptoTest, Passphrase) {
   EXPECT_FALSE(IsPassphraseValid(""));
   EXPECT_FALSE(IsPassphraseValid(bip_passphrase + " something wrong"));
   EXPECT_FALSE(IsPassphraseValid(bip_invalid_passphrase));
+  // It makes more sense to check against additional word from bip39 list
+  EXPECT_FALSE(IsPassphraseValid(bip_passphrase + " annual"));
 }
 
 }  // namespace crypto