From: Stefano Brivio <sbrivio@redhat.com>
To: Eric Dumazet <edumazet@google.com>
Cc: "David S . Miller" <davem@davemloft.net>,
netdev <netdev@vger.kernel.org>,
Eric Dumazet <eric.dumazet@gmail.com>,
syzbot <syzkaller@googlegroups.com>,
Sabrina Dubroca <sd@queasysnail.net>
Subject: Re: [PATCH net] fou, fou6: do not assume linear skbs
Date: Fri, 11 Jan 2019 15:15:07 +0100 [thread overview]
Message-ID: <20190111151507.393bab41@redhat.com> (raw)
In-Reply-To: <20190111125552.148871-1-edumazet@google.com>
On Fri, 11 Jan 2019 04:55:52 -0800
Eric Dumazet <edumazet@google.com> wrote:
> Both gue_err() and gue6_err() incorrectly assume
> linear skbs. Fix them to use pskb_may_pull().
Thanks for fixing this! I stupidly didn't suspect we could get
non-linear skbs there. Just two things:
> +++ b/net/ipv4/fou.c
> @@ -1020,10 +1020,11 @@ static int gue_err(struct sk_buff *skb, u32 info)
> {
> int transport_offset = skb_transport_offset(skb);
> struct guehdr *guehdr;
> - size_t optlen;
> + size_t len, optlen;
> int ret;
>
> - if (skb->len < sizeof(struct udphdr) + sizeof(struct guehdr))
> + len = sizeof(struct udphdr) + sizeof(struct guehdr);
> + if (!pskb_may_pull(skb, len))
> return -EINVAL;
>
> guehdr = (struct guehdr *)&udp_hdr(skb)[1];
> @@ -1058,6 +1059,10 @@ static int gue_err(struct sk_buff *skb, u32 info)
>
> optlen = guehdr->hlen << 2;
>
> + if (!pskb_may_pull(skb, len + optlen)
^ ) missing
> + return -EINVAL;
> +
> + guehdr = (struct guehdr *)&udp_hdr(skb)[1];
> if (validate_gue_flags(guehdr, optlen))
> return -EINVAL;
>
> diff --git a/net/ipv6/fou6.c b/net/ipv6/fou6.c
> index 7da7bf3b7fe3953eeb60addfffd6687c4da582c4..320413af4890641e7199d7d7102e7d8c2794d557 100644
> --- a/net/ipv6/fou6.c
> +++ b/net/ipv6/fou6.c
> @@ -90,10 +90,11 @@ static int gue6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
> {
> int transport_offset = skb_transport_offset(skb);
> struct guehdr *guehdr;
> - size_t optlen;
> + size_t len, optlen;
> int ret;
>
> - if (skb->len < sizeof(struct udphdr) + sizeof(struct guehdr))
> + len = sizeof(struct udphdr) + sizeof(struct guehdr);
> + if (!pskb_may_pull(skb, len))
> return -EINVAL;
>
> guehdr = (struct guehdr *)&udp_hdr(skb)[1];
> @@ -128,6 +129,10 @@ static int gue6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
>
> optlen = guehdr->hlen << 2;
>
> + if (!pskb_may_pull(skb, len + optlen)
^ ) missing
> + return -EINVAL;
> +
> + guehdr = (struct guehdr *)&udp_hdr(skb)[1];
> if (validate_gue_flags(guehdr, optlen))
> return -EINVAL;
>
--
Stefano
next prev parent reply other threads:[~2019-01-11 14:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-11 12:55 [PATCH net] fou, fou6: do not assume linear skbs Eric Dumazet
2019-01-11 14:15 ` Stefano Brivio [this message]
2019-01-11 14:20 ` Eric Dumazet
2019-01-11 14:23 ` Eric Dumazet
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190111151507.393bab41@redhat.com \
--to=sbrivio@redhat.com \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=eric.dumazet@gmail.com \
--cc=netdev@vger.kernel.org \
--cc=sd@queasysnail.net \
--cc=syzkaller@googlegroups.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).