linux-kernel - Re: linux-4.14-rc1/kernel/sysctl.c:2188: possible cut'n'paste error ?

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Date:   Mon, 18 Sep 2017 14:04:43 -0700
From:   Kees Cook <keescook@...omium.org>
To:     David Binderman <dcb314@...mail.com>
Cc:     "mcgrof@...nel.org" <mcgrof@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>
Subject: Re: linux-4.14-rc1/kernel/sysctl.c:2188: possible cut'n'paste error ?

On Mon, Sep 18, 2017 at 1:53 PM, David Binderman <dcb314@...mail.com> wrote:
> Hello there,
>
> linux-4.14-rc1/kernel/sysctl.c:2188] -> [linux-4.14-rc1/kernel/sysctl.c:2190]: (warning) Identical condition '*lvalp>UINT_MAX', second condition is always false
>
> Source code is
>
>         if (*lvalp > UINT_MAX)
>             return -EINVAL;
>         if (*lvalp > UINT_MAX)
>             return -EINVAL;
>
> Suggest remove second if test.

commit 4f2fec00afa6 ("sysctl: simplify unsigned int support") removed
"negp", but missed the duplication:

-static int do_proc_douintvec_conv(bool *negp, unsigned long *lvalp,
-                                int *valp,
-                                int write, void *data)
+static int do_proc_douintvec_conv(unsigned long *lvalp,
+                                 unsigned int *valp,
+                                 int write, void *data)
 {
        if (write) {
-               if (*negp)
+               if (*lvalp > UINT_MAX)
                        return -EINVAL;
                if (*lvalp > UINT_MAX)
                        return -EINVAL;

David, do you want to send a patch?

-Kees

-- 
Kees Cook
Pixel Security