Pass all characters to SecureString including nulls

`SecureString` is a `std::string` specialization with
a secure allocator. However, it's treated like a C-
string (no explicit length and null-terminated). This
can cause unexpected behavior. For instance, if a user
enters a passphrase with an embedded null character
(which is possible through Qt and the JSON-RPC), it will
ignore any characters after the null, giving the user
a false sense of security.

Instead of assigning `SecureString` via `std::string::c_str()`,
assign it via a `std::string_view` of the original. This
explicitly captures the size and doesn't make any extraneous
copies in memory.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/support/allocators/secure.h b/src/support/allocators/secure.h
index c6bd685189..a0918bf463 100644
--- a/src/support/allocators/secure.h
+++ b/src/support/allocators/secure.h
@@ -56,6 +56,7 @@ struct secure_allocator : public std::allocator<T> {
 };
 
 // This is exactly like std::string, but with a custom allocator.
+// TODO: Consider finding a way to make incoming RPC request.params[i] mlock()ed as well
 typedef std::basic_string<char, std::char_traits<char>, secure_allocator<char> > SecureString;
 
 #endif // BITCOIN_SUPPORT_ALLOCATORS_SECURE_H