From: Andrew Morton <akpm@linux-foundation.org>
To: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>,
Kees Cook <keescook@chromium.org>,
Don Zickus <dzickus@redhat.com>,
Al Viro <viro@zeniv.linux.org.uk>, Dave Young <dyoung@redhat.com>,
Hugh Dickins <hughd@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Daniel Cashman <dcashman@google.com>, Willy Tarreau <w@1wt.eu>,
Alexei Starovoitov <ast@plumgrid.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Ilya Dryomov <idryomov@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1] kernel/sysctl.c: avoid overflow
Date: Tue, 14 Jun 2016 13:19:06 -0700 [thread overview]
Message-ID: <20160614131906.4a5a9db55946735fbd57c4f5@linux-foundation.org> (raw)
In-Reply-To: <1465608788-4813-1-git-send-email-xypron.glpk@gmx.de>
On Sat, 11 Jun 2016 03:33:08 +0200 Heinrich Schuchardt <xypron.glpk@gmx.de> wrote:
> An undetected overflow may occur in do_proc_dointvec_minmax_conv_param.
>
> ...
>
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -2313,7 +2313,17 @@ static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
> {
> struct do_proc_dointvec_minmax_conv_param *param = data;
> if (write) {
> - int val = *negp ? -*lvalp : *lvalp;
> + int val;
> +
> + if (*negp) {
> + if (*lvalp > (unsigned long) INT_MAX + 1)
> + return -EINVAL;
> + val = -*lvalp;
> + } else {
> + if (*lvalp > (unsigned long) INT_MAX)
> + return -EINVAL;
> + val = *lvalp;
> + }
> if ((param->min && *param->min > val) ||
> (param->max && *param->max < val))
> return -EINVAL;
hm.
What happens if someone does
echo -1 > /proc/foo
expecting to get 0xffffffff? That's a reasonable shorthand, and if we
change that to spit out EINVAL then people's stuff may break.
next prev parent reply other threads:[~2016-06-14 20:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-11 1:33 Heinrich Schuchardt
2016-06-14 18:33 ` Kees Cook
2016-06-14 20:19 ` Andrew Morton [this message]
2016-06-14 20:41 ` Willy Tarreau
2016-06-15 8:33 ` Dave Young
2016-06-15 8:40 ` Willy Tarreau
2016-06-15 8:50 ` Dave Young
2016-06-14 21:05 ` Kees Cook
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