From 6c45d2c4795dd3abe12b4f5fd95ec20ae019b90c Mon Sep 17 00:00:00 2001
From: levlam <levlam@telegram.org>
Date: Thu, 9 Aug 2018 21:03:21 +0300
Subject: [PATCH] Make BigNum::from_decimal safe.

GitOrigin-RevId: bc414c62024d0f971d3400fec738545f898654a4
---
 tdutils/td/utils/BigNum.cpp |  8 +++++---
 tdutils/td/utils/BigNum.h   |  3 ++-
 tdutils/test/misc.cpp       | 15 +++++++++++++++
 tdutils/test/pq.cpp         |  4 ++--
 4 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/tdutils/td/utils/BigNum.cpp b/tdutils/td/utils/BigNum.cpp
index 6e21b435b..2b6331436 100644
--- a/tdutils/td/utils/BigNum.cpp
+++ b/tdutils/td/utils/BigNum.cpp
@@ -85,10 +85,12 @@ BigNum BigNum::from_binary(Slice str) {
   return BigNum(make_unique<Impl>(BN_bin2bn(str.ubegin(), narrow_cast<int>(str.size()), nullptr)));
 }
 
-BigNum BigNum::from_decimal(CSlice str) {
+Result<BigNum> BigNum::from_decimal(CSlice str) {
   BigNum result;
-  int err = BN_dec2bn(&result.impl_->big_num, str.c_str());
-  LOG_IF(FATAL, err == 0);
+  int res = BN_dec2bn(&result.impl_->big_num, str.c_str());
+  if (res == 0 || static_cast<size_t>(res) != str.size()) {
+    return Status::Error(PSLICE() << "Failed to parse \"" << str << "\" as BigNum");
+  }
   return result;
 }
 
diff --git a/tdutils/td/utils/BigNum.h b/tdutils/td/utils/BigNum.h
index 8de4e5871..a94b16173 100644
--- a/tdutils/td/utils/BigNum.h
+++ b/tdutils/td/utils/BigNum.h
@@ -11,6 +11,7 @@
 #if TD_HAVE_OPENSSL
 
 #include "td/utils/Slice.h"
+#include "td/utils/Status.h"
 
 namespace td {
 
@@ -41,7 +42,7 @@ class BigNum {
 
   static BigNum from_binary(Slice str);
 
-  static BigNum from_decimal(CSlice str);
+  static Result<BigNum> from_decimal(CSlice str);
 
   static BigNum from_raw(void *openssl_big_num);
 
diff --git a/tdutils/test/misc.cpp b/tdutils/test/misc.cpp
index 3a251229a..0280d819c 100644
--- a/tdutils/test/misc.cpp
+++ b/tdutils/test/misc.cpp
@@ -5,6 +5,7 @@
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 //
 #include "td/utils/base64.h"
+#include "td/utils/BigNum.h"
 #include "td/utils/HttpUrl.h"
 #include "td/utils/logging.h"
 #include "td/utils/misc.h"
@@ -404,3 +405,17 @@ TEST(Misc, unicode) {
   test_unicode(unicode_to_lower);
   test_unicode(remove_diacritics);
 }
+
+TEST(BigNum, from_decimal) {
+  ASSERT_TRUE(BigNum::from_decimal("").is_error());
+  ASSERT_TRUE(BigNum::from_decimal("a").is_error());
+  ASSERT_TRUE(BigNum::from_decimal("123a").is_error());
+  ASSERT_TRUE(BigNum::from_decimal("-123a").is_error());
+  // ASSERT_TRUE(BigNum::from_decimal("-").is_error());
+  ASSERT_TRUE(BigNum::from_decimal("123").is_ok());
+  ASSERT_TRUE(BigNum::from_decimal("-123").is_ok());
+  ASSERT_TRUE(BigNum::from_decimal("0").is_ok());
+  ASSERT_TRUE(BigNum::from_decimal("-0").is_ok());
+  ASSERT_TRUE(BigNum::from_decimal("-999999999999999999999999999999999999999999999999").is_ok());
+  ASSERT_TRUE(BigNum::from_decimal("999999999999999999999999999999999999999999999999").is_ok());
+}
diff --git a/tdutils/test/pq.cpp b/tdutils/test/pq.cpp
index c70527e10..8260c8b59 100644
--- a/tdutils/test/pq.cpp
+++ b/tdutils/test/pq.cpp
@@ -70,8 +70,8 @@ static std::vector<PqQuery> gen_pq_queries() {
 }
 
 static void test_pq(uint64 first, uint64 second) {
-  BigNum p = BigNum::from_decimal(PSLICE() << first);
-  BigNum q = BigNum::from_decimal(PSLICE() << second);
+  BigNum p = BigNum::from_decimal(PSLICE() << first).move_as_ok();
+  BigNum q = BigNum::from_decimal(PSLICE() << second).move_as_ok();
 
   BigNum pq;
   BigNumContext context;