From: Sabrina Dubroca <sd@queasysnail.net>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
David.Laight@aculab.com, kernel-hardening@lists.openwall.com,
davem@davemloft.net
Subject: Re: [PATCH v6 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow
Date: Fri, 28 Apr 2017 18:18:40 +0200 [thread overview]
Message-ID: <20170428161840.GA30423@bistromath.localdomain> (raw)
In-Reply-To: <20170425184734.26563-1-Jason@zx2c4.com>
2017-04-25, 20:47:30 +0200, Jason A. Donenfeld wrote:
> This is a defense-in-depth measure in response to bugs like
> 4d6fa57b4dab ("macsec: avoid heap overflow in skb_to_sgvec"). While
> we're at it, we also limit the amount of recursion this function is
> allowed to do. Not actually providing a bounded base case is a future
> diaster that we can easily avoid here.
>
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
> ---
> Changes v5->v6:
> * Use unlikely() for the rare overflow conditions.
> * Also bound recursion, since this is a potential disaster we can avert.
>
> net/core/skbuff.c | 31 ++++++++++++++++++++++++-------
> 1 file changed, 24 insertions(+), 7 deletions(-)
>
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index f86bf69cfb8d..24fb53f8534e 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -3489,16 +3489,22 @@ void __init skb_init(void)
> * @len: Length of buffer space to be mapped
> *
> * Fill the specified scatter-gather list with mappings/pointers into a
> - * region of the buffer space attached to a socket buffer.
> + * region of the buffer space attached to a socket buffer. Returns either
> + * the number of scatterlist items used, or -EMSGSIZE if the contents
> + * could not fit.
> */
One small thing here: since you're touching this comment, could you
move it next to skb_to_sgvec, since that's the function it's supposed
to document?
Thanks!
> static int
> -__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
> +__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len,
> + unsigned int recursion_level)
--
Sabrina
next prev parent reply other threads:[~2017-04-28 16:18 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-25 14:08 [PATCH 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow Jason A. Donenfeld
2017-04-25 14:08 ` [PATCH 2/5] ipsec: check return value of skb_to_sgvec always Jason A. Donenfeld
2017-04-25 14:08 ` [PATCH 3/5] rxrpc: " Jason A. Donenfeld
2017-04-25 14:08 ` [PATCH 4/5] macsec: " Jason A. Donenfeld
2017-04-25 14:08 ` [PATCH 5/5] virtio_net: " Jason A. Donenfeld
2017-04-25 14:16 ` [PATCH v2 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow Jason A. Donenfeld
2017-04-25 14:21 ` [PATCH v3 " Jason A. Donenfeld
2017-04-25 14:47 ` [PATCH " David Miller
2017-04-25 15:04 ` [PATCH v4 " Jason A. Donenfeld
2017-04-25 15:17 ` David Miller
2017-04-25 15:52 ` [PATCH v5 " Jason A. Donenfeld
2017-04-25 15:52 ` [PATCH v5 2/5] ipsec: check return value of skb_to_sgvec always Jason A. Donenfeld
2017-04-25 15:52 ` [PATCH v5 3/5] rxrpc: " Jason A. Donenfeld
2017-04-25 15:52 ` [PATCH v5 4/5] macsec: " Jason A. Donenfeld
2017-04-25 15:52 ` [PATCH v5 5/5] virtio_net: " Jason A. Donenfeld
2017-04-25 18:47 ` [PATCH v6 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow Jason A. Donenfeld
2017-04-25 18:47 ` [PATCH v6 2/5] ipsec: check return value of skb_to_sgvec always Jason A. Donenfeld
2017-04-25 18:47 ` [PATCH v6 3/5] rxrpc: " Jason A. Donenfeld
2017-04-28 11:41 ` Sabrina Dubroca
2017-04-28 13:29 ` Jason A. Donenfeld
2017-04-25 18:47 ` [PATCH v6 4/5] macsec: " Jason A. Donenfeld
2017-04-25 18:47 ` [PATCH v6 5/5] virtio_net: " Jason A. Donenfeld
2017-04-27 9:21 ` [PATCH v6 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow Jason A. Donenfeld
2017-04-27 11:30 ` Sabrina Dubroca
2017-04-27 12:04 ` Jason A. Donenfeld
2017-04-27 14:54 ` David Laight
2017-04-27 15:54 ` David Miller
2017-04-28 16:18 ` Sabrina Dubroca [this message]
2017-04-28 22:47 ` Jason A. Donenfeld
2017-04-25 15:42 ` [PATCH " Sergei Shtylyov
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