mirrors/scylladb
1
0
Fork 0
mirror of https://github.com/scylladb/scylladb.git synced 2026-05-12 19:02:12 +00:00
Code Issues Packages Projects Releases Wiki Activity

cql3 : add workaround to antlr3 null dereference bug

Browse Source 
The Antlr3 exception class has a null dereference bug that crashes
the system when trying to extract the exception message using
ANTLR_Exception<...>::displayRecognitionError(...) function. When
a parsing error occurs the CqlParser throws an exception which in
turn processesed for some special cases in scylla to generate a custom
message. The default case however, creates the message using
displayRecognitionError, causing the system to crash.
The fix is a simple workaround, making sure the pointer is not null
before the call to the function. A "proper" fix can't be implemented
because the exception class itself is implemented outside scylla
in antlr headers that resides on the host machine os.

Tested manualy 2 testcases, a typo causing scylla to crash and
a cql comment without a newline at the end also caused scylla to crash.
Ran unit tests (release).

Fixes #3740
Fixes #3764

Signed-off-by: Eliran Sinvani <eliransin@scylladb.com>
Message-Id: <cfc7e0d758d7a855d113bb7c8191b0fd7d2e8921.1538566542.git.eliransin@scylladb.com>
This commit is contained in:
Eliran Sinvani
2018-10-03 14:38:04 +03:00
committed by Avi Kivity
parent 9c57abcce7
commit 20f49566a2
1 changed files with 18 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
cql3/error_collector.hh
View File

@@ -67,6 +67,12 @@ class error_collector : public error_listener<RecognizerType, ExceptionBaseType>
*/
const sstring_view _query;
/**
* An empty bitset to be used as a workaround for AntLR null dereference
* bug.
*/
static typename ExceptionBaseType::BitsetListType _empty_bit_list;
public:
/**
@@ -144,6 +150,14 @@ private:
break;
}
default:
// AntLR Exception class has a bug of dereferencing a null
// pointer in the displayRecognitionError. The following
// if statement makes sure it will not be null before the
// call to that function (displayRecognitionError).
// bug reference: https://github.com/antlr/antlr3/issues/191
if (!ex->get_expectingSet()) {
ex->set_expectingSet(&_empty_bit_list);
}
ex->displayRecognitionError(token_names, msg);
}
return msg.str();
@@ -345,4 +359,8 @@ private:
#endif
};
template<typename RecognizerType, typename TokenType, typename ExceptionBaseType>
typename ExceptionBaseType::BitsetListType
error_collector<RecognizerType,TokenType,ExceptionBaseType>::_empty_bit_list = typename ExceptionBaseType::BitsetListType();
}