netdev - Re: [PATCH] net: don't unnecessarily load kernel modules in dev

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 07 Mar 2018 15:13:32 -0500 (EST)
From:   David Miller <davem@...emloft.net>
To:     paul@...l-moore.com
Cc:     pmoore@...hat.com, netdev@...r.kernel.org, viro@...iv.linux.org.uk,
        dac.override@...il.com, selinux@...ho.nsa.gov,
        linux-security-module@...r.kernel.org
Subject: Re: [PATCH] net: don't unnecessarily load kernel modules in
 dev_ioctl()

From: Paul Moore <paul@...l-moore.com>
Date: Tue, 6 Mar 2018 17:32:47 -0500

> On Tue, Mar 6, 2018 at 5:27 PM, Paul Moore <pmoore@...hat.com> wrote:
>> From: Paul Moore <paul@...l-moore.com>
>>
>> Starting with v4.16-rc1 we've been seeing a higher than usual number
>> of requests for the kernel to load networking modules, even on events
>> which shouldn't trigger a module load (e.g. ioctl(TCGETS)).  Stephen
>> Smalley suggested the problem may lie in commit 44c02a2c3dc5
>> ("dev_ioctl(): move copyin/copyout to callers") which moves changes
>> the network dev_ioctl() function to always call dev_load(),
>> regardless of the requested ioctl.
>>
>> This patch moves the dev_load() calls back into the individual ioctls
>> while preserving the rest of the original patch.
>>
>> Reported-by: Dominick Grift <dac.override@...il.com>
>> Suggested-by: Stephen Smalley <sds@...ho.nsa.gov>
>> Signed-off-by: Paul Moore <paul@...l-moore.com>
>> ---
>>  net/core/dev_ioctl.c |    7 +++++--
>>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> In the interest of full disclosure, I've compiled this code but I
> haven't booted it yet (test kernel building now).  I just wanted to
> post this sooner rather than later in case the networking folks, or
> Al, had a different solution they would prefer.

This is definitely the right fix, so patch applied.

Taking the dev_load() out of that switch statement definitely has
side effects.