[Bug gdb/27133] Crash with set logging redirect and debugredirect

["cvs-commit at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=27133

--- Comment #2 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Lancelot SIX <lsix@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=59b59f08f6448a77730c8d8dde5871f1bf6806d0

commit 59b59f08f6448a77730c8d8dde5871f1bf6806d0
Author: Lancelot SIX <lsix@lancelotsix.com>
Date:   Fri Jan 1 20:11:28 2021 +0000

    Avoid use after free with logging and debug redirect.

    This patch addresses PR gdb/27133. Before it, the following succession
    of commands would cause gdb to crash:

            set logging redirect on
            set logging debugredirect on
            set logging on

    The problem eventually comes down to a use after free. The function
    cli_interp_base::set_logging is called with a unique_ptr argument that
    holds a pointer to the redirection file. In the problematic use case,
    no-one ever took ownership of that pointer (as far as unique_ptr is
    concerned), so the call to its dtor at the end of the function causes
    the file object to be deleted. Any later use of the pointer to the
    redirection file is therefore an error.

    This patch ensures that the unique_ptr is released  when required (so it
    does not assume ownership anymore). The internal logic of
    cli_interp_base::set_logging takes care of freeing the ui_file when it
    is not necessary anymore using the saved_output.file_to_delete field.

    gdb/ChangeLog:

            PR gdb/27133
            * cli/cli-interp.c (cli_interp_base::set_logging): Ensure the
            unique_ptr is released when the wrapped pointer is kept for later
            use.

    gdb/testsuite/ChangeLog:

            PR gdb/27133
            * gdb.base/ui-redirect.exp: Add test case that ensures that
            redirecting both logging and debug does not cause gdb to crash.

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