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Commit b10bf63c authored by Elliott Hughes's avatar Elliott Hughes Committed by Cherrypicker Worker
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libutils: clearer abort on overflow. 

Let's turn a bug into a feature... Since this code is built with intsan,
anyone who caused overflow here will have had an abort, so we know
no-one actually needs the BAD_INDEX return that was presumably the
original author's intent. So let's just mandate that, since it's a lot
harder to ignore an abort than it is to ignore an error return.

Bug: http://b/179044558
Test: treehugger
Change-Id: I08f1018f9da1e09de885699138b7543d55bb2a36
(cherry picked from commit a5f2e4d4)
Merged-In: I08f1018f9da1e09de885699138b7543d55bb2a36
parent 1a2dbd91

libutils/VectorImpl.cpp

+6 −8
Original line number Diff line number Diff line
@@ -279,12 +279,10 @@ ssize_t VectorImpl::replaceAt(const void* prototype, size_t index) 


ssize_t VectorImpl::removeItemsAt(size_t index, size_t count)

{

    ALOG_ASSERT((index+count)<=size(),

        "[%p] remove: index=%d, count=%d, size=%d",

               this, (int)index, (int)count, (int)size());



    if ((index+count) > size())

        return BAD_VALUE;

    size_t end;

    LOG_ALWAYS_FATAL_IF(__builtin_add_overflow(index, count, &end), "overflow: index=%zu count=%zu",

                        index, count);

    if (end > size()) return BAD_VALUE;

    _shrink(index, count);

    return index;

}

libutils/Vector_test.cpp

+9 −0
Original line number Diff line number Diff line
@@ -136,4 +136,13 @@ TEST_F(VectorTest, editArray_Shared) { 
  }

}



TEST_F(VectorTest, removeItemsAt_overflow) {

    android::Vector<int> v;

    for (int i = 0; i < 666; i++) v.add(i);



    ASSERT_DEATH(v.removeItemsAt(SIZE_MAX, 666), "overflow");

    ASSERT_DEATH(v.removeItemsAt(666, SIZE_MAX), "overflow");

    ASSERT_DEATH(v.removeItemsAt(SIZE_MAX, SIZE_MAX), "overflow");

}



} // namespace android