Re: [PATCH] more out of bounds checking improvements

[Florian Weimer <fweimer@redhat.com>]

* Martin Sebor:

> diff --git a/nss/makedb.c b/nss/makedb.c
> index 9389f6b548..6551b3cf2a 100644
> --- a/nss/makedb.c
> +++ b/nss/makedb.c
> @@ -792,14 +792,25 @@ write_output (int fd)
>                           + nhashentries_total * sizeof (stridx_t)));
>    header->allocate = file_offset;
>
> -  /* Help GCC 10 see iov_nelts doesn't overflow the writev argument.  */
>    assert (iov_nelts <= INT_MAX);
> +
> +#if __GNUC_PREREQ (10, 0)
> +  DIAG_PUSH_NEEDS_COMMENT;
> +  /* Avoid GCC 10 false positice warning: specified size exceeds maximum
> +     object size.  */
> +  DIAG_IGNORE_NEEDS_COMMENT (10, "-Wstringop-overflow");
> +#endif
> +
>    if (writev (fd, iov, iov_nelts) != keydataoffset)
>      {
>        error (0, errno, gettext ("failed to write new database file"));
>        return EXIT_FAILURE;
>      }
>
> +#if __GNUC_PREREQ (10, 0)
> +  DIAG_POP_NEEDS_COMMENT;
> +#endif
> +
>    return EXIT_SUCCESS;
>  }

Typo: positice

I'm building this with build-many-glibcs.py right now, first with GCC
11, then with GCC 10.  I don't have a GCC 10 tree yet, so it's goint to
take some time, hopefully less than two hours.

If the warning happens with GCC 10 only, should we disable it for GCC 11
as well?

Thanks,
Florian