[Bug libstdc++/93205] std::discrete_distribution's operator>> causes OOM

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93205

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by Jonathan Wakely
<redi@gcc.gnu.org>:

https://gcc.gnu.org/g:a29236a23c03fe08998b81a0ef1f67e7ea185ba3

commit r9-8289-ga29236a23c03fe08998b81a0ef1f67e7ea185ba3
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Feb 26 16:31:19 2020 +0000

    libstdc++: Fix undefined behaviour in random dist serialization (PR93205)

    The deserialization functions for random number distributions fail to
    check the stream state before using the extracted values. In some cases
    this leads to using indeterminate values to resize a vector, and then
    filling that vector with indeterminate values.

    No values that affect control flow should be used without checking that a
    good value was read from the stream.

    Additionally, where reasonable to do so, defer modifying any state in
    the distribution until all values have been successfully read, to avoid
    modifying some of the distribution's parameters and leaving others
    unchanged.

    Backport from mainline
    2020-01-09  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/93205
        * include/bits/random.h (operator>>): Check stream operation succeeds.
        * include/bits/random.tcc: (operator>>): Likewise.
        (__extract_params): New function to fill a vector from a stream.
        * testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error line.