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tdf#108039: check for nullptr in rtl_uString and OUString

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rtl_[u]String_newConcat now checks allocation result to return
early and avoid SIGSEGV. Other functions are not modified, to
keep old behavior relying on allocation success and crashing
early on OOM to avoid added overhead in performance-critical
places.

OUString operator+= now checks rtl_uString_newConcat result and
throws std::bad_alloc on failure, to specifically address BASIC
problem. It keeps strong exception guarantee of leaving this'
state unaltered.

Concatenation in BASIC now checks for bad string allocation
(previously SIGSEGV was generated).

Unit test included.

Change-Id: I1513311d3d58eac43b2d2ec9a230e22dff0b4245
Reviewed-on: https://gerrit.libreoffice.org/37965
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
Tested-by: Jenkins <ci@libreoffice.org>
This commit is contained in:
Mike Kaganski
2017-05-23 23:57:50 +03:00
parent 9d1edef89b
commit ef117cad3a
4 changed files with 43 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
basic/qa/basic_coverage/test_string_overflow_safe.vb Normal file
View File

@@ -0,0 +1,22 @@
Option Explicit
Function doUnitTest As Integer
' Trying to create too long string should generate proper BASIC overflow error.
' Longest possible string is 2147483638 wchar_t (2G - 10).
' This tries to create string with 2G wchar_t. If it does not overflow, test fails.
' If overflow is not safe, it segfaults.
On Error GoTo errorHandler
Dim s As String, i As Integer
s = "0"
For i=1 To 31
s = s & s
Next i
doUnitTest = 0
Exit Function
errorHandler:
If ( Err <> 6 ) Then
doUnitTest = 0
Else
doUnitTest = 1
Endif
End Function

9
basic/source/sbx/sbxvalue.cxx
View File

@@ -875,14 +875,19 @@ bool SbxValue::Compute( SbxOperator eOp, const SbxValue& rOp )
// #30576: To begin with test, if the conversion worked
if( aL.pOUString != nullptr && aR.pOUString != nullptr )
{
*aL.pOUString += *aR.pOUString;
// tdf#108039: catch possible bad_alloc
try {
*aL.pOUString += *aR.pOUString;
}
catch (const std::bad_alloc&) {
SetError(ERRCODE_SBX_OVERFLOW);
}
}
// Not even Left OK?
else if( aL.pOUString == nullptr )
{
aL.pOUString = new OUString();
}
Put( aL );
}
else
SetError( ERRCODE_SBX_CONVERSION );

10
include/rtl/ustring.hxx
View File

@@ -519,13 +519,21 @@ public:
Append a string to this string.
@param str a OUString.
@exception std::bad_alloc is thrown if an out-of-memory condition occurs
*/
OUString & operator+=( const OUString & str )
#if defined LIBO_INTERNAL_ONLY && HAVE_CXX11_REF_QUALIFIER
&
#endif
{
rtl_uString_newConcat( &pData, pData, str.pData );
rtl_uString* pNewData = NULL;
rtl_uString_newConcat( &pNewData, pData, str.pData );
if (pNewData == NULL) {
throw std::bad_alloc();
}
rtl_uString_assign(&pData, pNewData);
rtl_uString_release(pNewData);
return *this;
}
#if defined LIBO_INTERNAL_ONLY && HAVE_CXX11_REF_QUALIFIER

8
sal/rtl/strtmpl.cxx
View File

@@ -1507,11 +1507,13 @@ void SAL_CALL IMPL_RTL_STRINGNAME( newConcat )( IMPL_RTL_STRINGDATA** ppThis,
{
IMPL_RTL_STRINGDATA* pTempStr = IMPL_RTL_STRINGNAME( ImplAlloc )( pLeft->length + pRight->length );
OSL_ASSERT(pTempStr != nullptr);
rtl_str_ImplCopy( pTempStr->buffer, pLeft->buffer, pLeft->length );
rtl_str_ImplCopy( pTempStr->buffer+pLeft->length, pRight->buffer, pRight->length );
*ppThis = pTempStr;
if (*ppThis != nullptr) {
rtl_str_ImplCopy( pTempStr->buffer, pLeft->buffer, pLeft->length );
rtl_str_ImplCopy( pTempStr->buffer+pLeft->length, pRight->buffer, pRight->length );
RTL_LOG_STRING_NEW( *ppThis );
RTL_LOG_STRING_NEW( *ppThis );
}
}
/* must be done last, if left or right == *ppThis */