|str| was used for multiple conflicting purposes. When using
'-strictpem', it's used to uniquely hold a reference to the loaded
payload. However, when using '-strparse', |str| was re-used to hold
the position from where to start parsing.
So when '-strparse' and '-strictpem' are were together, |str| ended up
pointing into data pointed at by |at|, and was yet being freed, with
the result that the payload it held a reference to became a memory
leak, and there was a double free conflict when both |str| and |at|
were being freed.
The situation is resolved by always having |buf| hold the pointer to
the file data, and always and only use |str| to hold the position to
start parsing from. Now, we only need to free |buf| properly and not
|str|.
Fixes#8752
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/8753)
4f29f3a29b