fa1b89a6bd scripted-diff: Rename nReadPos to m_read_pos in streams.h (MarcoFalke)
fa56c79df9 Make CDataStream work properly on 64-bit systems (MarcoFalke)
fab02f7991 streams: Fix read-past-the-end and integer overflows (MarcoFalke)
Pull request description:
This is a follow-up to commit e26b62093a with the following fixes:
* Fix unsigned integer overflow in `ignore()`, when `nReadPos` wraps.
* Fix unsigned integer overflow in `read()`, when `nReadPos` wraps.
* Fix read-past-the-end in `read()`, when `nReadPos` wraps.
This shouldn't be remote-exploitable, because it requires a stream of more than 1GB of size. However, it might be exploitable if the attacker controls the datadir (I haven't checked).
A unit test for the overflow in `ignore()` looks like following. It is left as an excercise to the reader to replace `foo.ignore(7)` with the appropriate call to `read()` to reproduce the overflow and read-error in `read()`.
```diff
diff --git a/src/test/coins_tests.cpp b/src/test/coins_tests.cpp
index 922fd8e513..ec6ea93919 100644
--- a/src/test/coins_tests.cpp
+++ b/src/test/coins_tests.cpp
@@ -534,6 +534,20 @@ BOOST_AUTO_TEST_CASE(ccoins_serialization)
} catch (const std::ios_base::failure&) {
}
+ CDataStream foo{0, 0};
+ auto size{std::numeric_limits<uint32_t>::max()};
+ foo.resize(size);
+ BOOST_CHECK_EQUAL(foo.size(), size);
+ foo.ignore(std::numeric_limits<int32_t>::max());
+ size -= std::numeric_limits<int32_t>::max();
+ BOOST_CHECK_EQUAL(foo.size(), size);
+ foo.ignore(std::numeric_limits<int32_t>::max());
+ size -= std::numeric_limits<int32_t>::max();
+ BOOST_CHECK_EQUAL(foo.size(), size);
+ BOOST_CHECK_EQUAL(foo.size(), 1);
+ foo.ignore(7); // Should overflow, as the size is only 1
+ BOOST_CHECK_EQUAL(foo.size(), uint32_t(1 - 7));
+
// Very large scriptPubKey (3*10^9 bytes) past the end of the stream
CDataStream tmp(SER_DISK, CLIENT_VERSION);
uint64_t x = 3000000000ULL;
```
ACKs for top commit:
klementtan:
Code Review ACK fa1b89a6bd:
Tree-SHA512: 67f0a1baafe88eaf1dc844ac55b638d5cf168a18c945e3bf7a2cb03c9a5976674a8e3af2487d8a2c3eae21e5c0e7a519c8b16ee7f104934442e2769d100660e9
abaf943477