Lucid CVE-2010-3880, inet_diag: Make sure we actually run the same bytecode we audited

[Brad Figg]

On 02/02/2011 10:59 AM, Tim Gardner wrote:
> The following changes since commit c164bea3e14f2b8da7241f9b756143d6434ac303:
>    Kulikov Vasiliy (1):
>          net: tipc: fix information leak to userland, CVE-2010-3877
>
> are available in the git repository at:
>
>    git://kernel.ubuntu.com/rtg/ubuntu-lucid.git CVE-2010-3880
>
> Nelson Elhage (1):
>        inet_diag: Make sure we actually run the same bytecode we audited, CVE-2010-3880
>
>   include/net/netlink.h |    2 +-
>   net/ipv4/inet_diag.c  |   27 ++++++++++++++++-----------
>   2 files changed, 17 insertions(+), 12 deletions(-)
>
>  From 55c14fda6f8ef5d2ac75045de14abe21fc69975b Mon Sep 17 00:00:00 2001
> From: Nelson Elhage<nelhage at ksplice.com>
> Date: Wed, 3 Nov 2010 16:35:41 +0000
> Subject: [PATCH] inet_diag: Make sure we actually run the same bytecode we audited, CVE-2010-3880
>
> BugLink: http://bugs.launchpad.net/bugs/711865
>
> CVE-2010-3880
>
> We were using nlmsg_find_attr() to look up the bytecode by attribute when
> auditing, but then just using the first attribute when actually running
> bytecode. So, if we received a message with two attribute elements, where only
> the second had type INET_DIAG_REQ_BYTECODE, we would validate and run different
> bytecode strings.
>
> Fix this by consistently using nlmsg_find_attr everywhere.
>
> Signed-off-by: Nelson Elhage<nelhage at ksplice.com>
> Signed-off-by: Thomas Graf<tgraf at infradead.org>
> Signed-off-by: David S. Miller<davem at davemloft.net>
> (back ported from commit 22e76c849d505d87c5ecf3d3e6742a65f0ff4860)
>
> Signed-off-by: Tim Gardner<tim.gardner at canonical.com>
> ---
>   include/net/netlink.h |    2 +-
>   net/ipv4/inet_diag.c  |   27 ++++++++++++++++-----------
>   2 files changed, 17 insertions(+), 12 deletions(-)
>
> diff --git a/include/net/netlink.h b/include/net/netlink.h
> index a63b219..c344646 100644
> --- a/include/net/netlink.h
> +++ b/include/net/netlink.h
> @@ -384,7 +384,7 @@ static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
>    *
>    * Returns the first attribute which matches the specified type.
>    */
> -static inline struct nlattr *nlmsg_find_attr(struct nlmsghdr *nlh,
> +static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
>   					     int hdrlen, int attrtype)
>   {
>   	return nla_find(nlmsg_attrdata(nlh, hdrlen),
> diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
> index a706a47..6fe360f 100644
> --- a/net/ipv4/inet_diag.c
> +++ b/net/ipv4/inet_diag.c
> @@ -489,9 +489,11 @@ static int inet_csk_diag_dump(struct sock *sk,
>   {
>   	struct inet_diag_req *r = NLMSG_DATA(cb->nlh);
>
> -	if (cb->nlh->nlmsg_len>  4 + NLMSG_SPACE(sizeof(*r))) {
> +	if (nlmsg_attrlen(cb->nlh, sizeof(*r))) {
>   		struct inet_diag_entry entry;
> -		struct rtattr *bc = (struct rtattr *)(r + 1);
> +		const struct nlattr *bc = nlmsg_find_attr(cb->nlh,
> +							  sizeof(*r),
> +							  INET_DIAG_REQ_BYTECODE);
>   		struct inet_sock *inet = inet_sk(sk);
>
>   		entry.family = sk->sk_family;
> @@ -511,7 +513,7 @@ static int inet_csk_diag_dump(struct sock *sk,
>   		entry.dport = ntohs(inet->dport);
>   		entry.userlocks = sk->sk_userlocks;
>
> -		if (!inet_diag_bc_run(RTA_DATA(bc), RTA_PAYLOAD(bc),&entry))
> +		if (!inet_diag_bc_run(nla_data(bc), nla_len(bc),&entry))
>   			return 0;
>   	}
>
> @@ -526,9 +528,11 @@ static int inet_twsk_diag_dump(struct inet_timewait_sock *tw,
>   {
>   	struct inet_diag_req *r = NLMSG_DATA(cb->nlh);
>
> -	if (cb->nlh->nlmsg_len>  4 + NLMSG_SPACE(sizeof(*r))) {
> +	if (nlmsg_attrlen(cb->nlh, sizeof(*r))) {
>   		struct inet_diag_entry entry;
> -		struct rtattr *bc = (struct rtattr *)(r + 1);
> +		const struct nlattr *bc = nlmsg_find_attr(cb->nlh,
> +							  sizeof(*r),
> +							  INET_DIAG_REQ_BYTECODE);
>
>   		entry.family = tw->tw_family;
>   #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
> @@ -547,7 +551,7 @@ static int inet_twsk_diag_dump(struct inet_timewait_sock *tw,
>   		entry.dport = ntohs(tw->tw_dport);
>   		entry.userlocks = 0;
>
> -		if (!inet_diag_bc_run(RTA_DATA(bc), RTA_PAYLOAD(bc),&entry))
> +		if (!inet_diag_bc_run(nla_data(bc), nla_len(bc),&entry))
>   			return 0;
>   	}
>
> @@ -617,7 +621,7 @@ static int inet_diag_dump_reqs(struct sk_buff *skb, struct sock *sk,
>   	struct inet_diag_req *r = NLMSG_DATA(cb->nlh);
>   	struct inet_connection_sock *icsk = inet_csk(sk);
>   	struct listen_sock *lopt;
> -	struct rtattr *bc = NULL;
> +	const struct nlattr *bc = NULL;
>   	struct inet_sock *inet = inet_sk(sk);
>   	int j, s_j;
>   	int reqnum, s_reqnum;
> @@ -637,8 +641,9 @@ static int inet_diag_dump_reqs(struct sk_buff *skb, struct sock *sk,
>   	if (!lopt || !lopt->qlen)
>   		goto out;
>
> -	if (cb->nlh->nlmsg_len>  4 + NLMSG_SPACE(sizeof(*r))) {
> -		bc = (struct rtattr *)(r + 1);
> +	if (nlmsg_attrlen(cb->nlh, sizeof(*r))) {
> +		bc = nlmsg_find_attr(cb->nlh, sizeof(*r),
> +				     INET_DIAG_REQ_BYTECODE);
>   		entry.sport = inet->num;
>   		entry.userlocks = sk->sk_userlocks;
>   	}
> @@ -671,8 +676,8 @@ static int inet_diag_dump_reqs(struct sk_buff *skb, struct sock *sk,
>   					&ireq->rmt_addr;
>   				entry.dport = ntohs(ireq->rmt_port);
>
> -				if (!inet_diag_bc_run(RTA_DATA(bc),
> -						    RTA_PAYLOAD(bc),&entry))
> +				if (!inet_diag_bc_run(nla_data(bc),
> +						      nla_len(bc),&entry))
>   					continue;
>   			}
>

Acked-by: Brad Figg <brad.figg at canonical.com>

-- 
Brad Figg brad.figg at canonical.com http://www.canonical.com