From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Heiko Carstens <hca@linux.ibm.com>
Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>
Subject: Re: [PATCH v1 1/1] s390: Use string_upper() instead of open coded variant
Date: Tue, 5 Oct 2021 11:18:38 +0300 [thread overview]
Message-ID: <YVwKXn1Nqwk+Ahsx@smile.fi.intel.com> (raw)
In-Reply-To: <YVtksmjj1eGqw5GY@osiris>
On Mon, Oct 04, 2021 at 10:31:46PM +0200, Heiko Carstens wrote:
> On Fri, Oct 01, 2021 at 04:02:01PM +0300, Andy Shevchenko wrote:
...
> > + /* Segment name is limited by 8 characters + NUL */
> > + char tmp[8 + 1];
> > int i;
> >
> > - for (i = 0; i < 8; i++) {
> > - if (name[i] == '\0')
> > - break;
> > - dcss_name[i] = toupper(name[i]);
> > - }
> > - for (; i < 8; i++)
> > - dcss_name[i] = ' ';
> > + /*
> > + * This snprintf() call does two things:
> > + * - makes a NUL-terminated copy of the input string
> > + * - pads it with spaces
> > + */
> > + snprintf(tmp, sizeof(tmp), "%s ", name);
>
> I can't say I like code where I have to count spaces in order to
> verify if the code is actually correct.
I understand your point, but have any idea how to make it differently
and not ugly at the same time?
> > + string_upper(dcss_name, tmp);
...
> > static struct dcss_segment *
> > segment_by_name (char *name)
> > {
> > - char dcss_name[9];
> > + char dcss_name[8];
>
> string_upper will copy the terminating NUL-byte. By reducing the size
> of dcss_name to 8 bytes this will result in stack corruption.
Nope. Even in the original code this additional byte is left unused.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2021-10-05 8:18 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-01 13:02 [PATCH v1 1/1] s390: Use string_upper() instead of open coded variant Andy Shevchenko
2021-10-04 20:31 ` Heiko Carstens
2021-10-05 8:18 ` Andy Shevchenko [this message]
2021-10-05 8:54 ` Heiko Carstens
2021-10-05 12:09 ` Andy Shevchenko
2021-10-11 8:21 ` David Laight
2021-10-11 10:09 ` Heiko Carstens
2021-10-12 8:04 ` David Laight
2021-10-12 9:12 ` Heiko Carstens
2021-10-07 18:07 ` Heiko Carstens
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