[C++] Reading some Parquet data can return uninitialized memory

[asfimport]

In #5365 we found via a UBSAN issue that Parquet decoding of RLE-encoded dict-encoded Parquet data with nulls does not initialize the output data array for null entries. Since the output data array is generally a freshly-allocated memory buffer, this means it will contain uninitialized memory.

Reporter: Antoine Pitrou / @pitrou
Assignee: Antoine Pitrou / @pitrou

Related issues:

• [C++] [Parquet] Using deprecated Int96 storage for timestamps triggers integer overflow in some cases (is duplicated by)

PRs and other links:

• GitHub Pull Request #5392

_{Note: This issue was originally created as ARROW-6572. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
Issue resolved by pull request 5392
#5392