lkml.org 
[lkml]   [2023]   [Aug]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] staging: rtl8192e: prefer strscpy over strncpy
On Wed, Aug 09, 2023 at 08:02:05PM +0200, Michael Straube wrote:
> On 8/9/23 14:21, Greg KH wrote:
> > On Sat, Aug 05, 2023 at 09:51:14AM +0200, Michael Straube wrote:
> > > Replace strncpy with strscpy in two places where the destination buffer
> > > should be NUL-terminated. Found by checkpatch.
> > >
> > > WARNING: Prefer strscpy, strscpy_pad, or __nonstring over strncpy - see: https://github.com/KSPP/linux/issues/90
> >
> > If a global search/replace could be done, it would have happend a long
> > time ago.
> >
> > How was this tested? The functions work differently, are you sure there
> > is no change in functionality here?
> >
>
> It was only compile tested. To me it looked as it does not change
> functionality, but looking a bit deeper at it I'm not sure anymore.
> So, we should leave it as is.

So there are three main differences between strncpy() and strcpy().

1) The return.
2) strncpy() will always write net->hidden_ssid_len bytes. If the
string to copy is smaller than net->hidden_ssid_len bytes it will
fill the rest with zeroes. This can be important for preventing
information leaks.
3) strscpy() will always add a NUL terminator where strncpy() just
truncates a too long string without adding a terminator.

We want #3. We don't care about #1. The only thing to check is #2.

regards,
dan carpenter

\
 
 \ /
  Last update: 2023-08-10 07:03    [W:0.069 / U:1.132 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site