Re: [PATCH] util/error: Fix use-after-free errors reported by Coverity

[Marc-André Lureau]

Hi

On Thu, Apr 6, 2023 at 7:43 PM Stefan Berger <stefanb@linux.ibm.com> wrote:
>
> Fix use-after-free errors in the code path that called error_handle(). A
> call to error_handle() will now either free the passed Error 'err' or
> assign it to '*errp' if '*errp' is currently NULL. This ensures that 'err'
> either has been freed or is assigned to '*errp' if this function returns.
> Adjust the two callers of this function to not assign the 'err' to '*errp'
> themselves, since this is now handled by error_handle().
>

Fixes: commit 3ffef1a55ca3 ("error: add global &error_warn destination")

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

worth including for 8.0 imho.

> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
> ---
>  util/error.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/util/error.c b/util/error.c
> index 5537245da6..e5e247209a 100644
> --- a/util/error.c
> +++ b/util/error.c
> @@ -46,6 +46,10 @@ static void error_handle(Error **errp, Error *err)
>      }
>      if (errp == &error_warn) {
>          warn_report_err(err);
> +    } else if (errp && !*errp) {
> +        *errp = err;
> +    } else {
> +        error_free(err);
>      }
>  }
>
> @@ -76,7 +80,6 @@ static void error_setv(Error **errp,
>      err->func = func;
>
>      error_handle(errp, err);
> -    *errp = err;
>
>      errno = saved_errno;
>  }
> @@ -289,11 +292,6 @@ void error_propagate(Error **dst_errp, Error *local_err)
>          return;
>      }
>      error_handle(dst_errp, local_err);
> -    if (dst_errp && !*dst_errp) {
> -        *dst_errp = local_err;
> -    } else {
> -        error_free(local_err);
> -    }
>  }
>
>  void error_propagate_prepend(Error **dst_errp, Error *err,
> --
> 2.39.1
>


-- 
Marc-André Lureau