netdev - Re: [PATCH nf] netfilter: xt_RATEEST: reject non-null terminated string from userspace

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Date:   Tue, 22 Dec 2020 23:50:10 +0100
From:   Florian Westphal <fw@...len.de>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Florian Westphal <fw@...len.de>,
        NetFilter <netfilter-devel@...r.kernel.org>,
        Netdev <netdev@...r.kernel.org>,
        syzkaller-bugs <syzkaller-bugs@...glegroups.com>,
        syzbot <syzbot+e86f7c428c8c50db65b4@...kaller.appspotmail.com>
Subject: Re: [PATCH nf] netfilter: xt_RATEEST: reject non-null terminated
 string from userspace

Linus Torvalds <torvalds@...ux-foundation.org> wrote:
> On Tue, Dec 22, 2020 at 2:24 PM Florian Westphal <fw@...len.de> wrote:
> >
> > strlcpy assumes src is a c-string. Check info->name before its used.
> 
> If strlcpy is the only problem, then the fix is to use strscpy(),
> which doesn't have the design mistake that strlcpy has.

It would silence the reproducer, but the checkentry function calls
__xt_rateest_lookup which may 'strcmp(..., maybe_not_zero_terminated)'.