linux-kernel - Re: [PATCH 14/18] ipv4: prevent bounds-check bypass via speculative execution

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <ed88131b-4da7-9dd5-0590-807ec71466ab@cogentembedded.com>
Date:   Sat, 6 Jan 2018 13:04:52 +0300
From:   Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:     Dan Williams <dan.j.williams@...el.com>,
        linux-kernel@...r.kernel.org
Cc:     linux-arch@...r.kernel.org,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        netdev@...r.kernel.org, peterz@...radead.org,
        gregkh@...uxfoundation.org,
        Alexey Kuznetsov <kuznet@....inr.ac.ru>, tglx@...utronix.de,
        torvalds@...ux-foundation.org,
        "David S. Miller" <davem@...emloft.net>,
        Elena Reshetova <elena.reshetova@...el.com>,
        alan@...ux.intel.com
Subject: Re: [PATCH 14/18] ipv4: prevent bounds-check bypass via speculative
 execution

On 1/6/2018 4:11 AM, Dan Williams wrote:

> Static analysis reports that 'offset' may be a user controlled value
> that is used as a data dependency reading from a raw_frag_vec buffer.
> In order to avoid potential leaks of kernel memory values, block
> speculative execution of the instruction stream that could issue further
> reads based on an invalid '*(rfv->c + offset)' value.
> 
> Based on an original patch by Elena Reshetova.
> 
> Cc: "David S. Miller" <davem@...emloft.net>
> Cc: Alexey Kuznetsov <kuznet@....inr.ac.ru>
> Cc: Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>
> Cc: netdev@...r.kernel.org
> Signed-off-by: Elena Reshetova <elena.reshetova@...el.com>
> Signed-off-by: Dan Williams <dan.j.williams@...el.com>
> ---
>   net/ipv4/raw.c |    9 +++++----
>   1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
> index 125c1eab3eaa..f72b20131a15 100644
> --- a/net/ipv4/raw.c
> +++ b/net/ipv4/raw.c
[...]
> @@ -472,17 +473,17 @@ static int raw_getfrag(void *from, char *to, int offset, int len, int odd,
>   		       struct sk_buff *skb)
>   {
>   	struct raw_frag_vec *rfv = from;
> +	char *rfv_buf;
>   
> -	if (offset < rfv->hlen) {
> +	if ((rfv_buf = nospec_array_ptr(rfv->hdr.c, offset, rfv->hlen))) {

    And here...

[...]

MBR, Sergei