From 676d23690fb62b5d51ba5d659935e9f7d9da9f8e Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Fri, 11 Apr 2014 16:15:36 -0400 Subject: net: Fix use after free by removing length arg from sk_data_ready callbacks. Several spots in the kernel perform a sequence like: skb_queue_tail(&sk->s_receive_queue, skb); sk->sk_data_ready(sk, skb->len); But at the moment we place the SKB onto the socket receive queue it can be consumed and freed up. So this skb->len access is potentially to freed up memory. Furthermore, the skb->len can be modified by the consumer so it is possible that the value isn't accurate. And finally, no actual implementation of this callback actually uses the length argument. And since nobody actually cared about it's value, lots of call sites pass arbitrary values in such as '0' and even '1'. So just remove the length argument from the callback, that way there is no confusion whatsoever and all of these use-after-free cases get fixed as a side effect. Based upon a patch by Eric Dumazet and his suggestion to audit this issue tree-wide. Signed-off-by: David S. Miller --- net/sunrpc/svcsock.c | 12 ++++++------ net/sunrpc/xprtsock.c | 8 ++++---- 2 files changed, 10 insertions(+), 10 deletions(-) (limited to 'net/sunrpc') diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index b6e59f0a9475..c26ce9556581 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -60,7 +60,7 @@ static struct svc_sock *svc_setup_socket(struct svc_serv *, struct socket *, int flags); -static void svc_udp_data_ready(struct sock *, int); +static void svc_udp_data_ready(struct sock *); static int svc_udp_recvfrom(struct svc_rqst *); static int svc_udp_sendto(struct svc_rqst *); static void svc_sock_detach(struct svc_xprt *); @@ -403,14 +403,14 @@ static void svc_sock_setbufsize(struct socket *sock, unsigned int snd, /* * INET callback when data has been received on the socket. */ -static void svc_udp_data_ready(struct sock *sk, int count) +static void svc_udp_data_ready(struct sock *sk) { struct svc_sock *svsk = (struct svc_sock *)sk->sk_user_data; wait_queue_head_t *wq = sk_sleep(sk); if (svsk) { - dprintk("svc: socket %p(inet %p), count=%d, busy=%d\n", - svsk, sk, count, + dprintk("svc: socket %p(inet %p), busy=%d\n", + svsk, sk, test_bit(XPT_BUSY, &svsk->sk_xprt.xpt_flags)); set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); svc_xprt_enqueue(&svsk->sk_xprt); @@ -731,7 +731,7 @@ static void svc_udp_init(struct svc_sock *svsk, struct svc_serv *serv) * A data_ready event on a listening socket means there's a connection * pending. Do not use state_change as a substitute for it. */ -static void svc_tcp_listen_data_ready(struct sock *sk, int count_unused) +static void svc_tcp_listen_data_ready(struct sock *sk) { struct svc_sock *svsk = (struct svc_sock *)sk->sk_user_data; wait_queue_head_t *wq; @@ -783,7 +783,7 @@ static void svc_tcp_state_change(struct sock *sk) wake_up_interruptible_all(wq); } -static void svc_tcp_data_ready(struct sock *sk, int count) +static void svc_tcp_data_ready(struct sock *sk) { struct svc_sock *svsk = (struct svc_sock *)sk->sk_user_data; wait_queue_head_t *wq = sk_sleep(sk); diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 966763d735e9..96458d434324 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -254,7 +254,7 @@ struct sock_xprt { /* * Saved socket callback addresses */ - void (*old_data_ready)(struct sock *, int); + void (*old_data_ready)(struct sock *); void (*old_state_change)(struct sock *); void (*old_write_space)(struct sock *); void (*old_error_report)(struct sock *); @@ -946,7 +946,7 @@ static int xs_local_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb) * * Currently this assumes we can read the whole reply in a single gulp. */ -static void xs_local_data_ready(struct sock *sk, int len) +static void xs_local_data_ready(struct sock *sk) { struct rpc_task *task; struct rpc_xprt *xprt; @@ -1009,7 +1009,7 @@ static void xs_local_data_ready(struct sock *sk, int len) * @len: how much data to read * */ -static void xs_udp_data_ready(struct sock *sk, int len) +static void xs_udp_data_ready(struct sock *sk) { struct rpc_task *task; struct rpc_xprt *xprt; @@ -1432,7 +1432,7 @@ static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, uns * @bytes: how much data to read * */ -static void xs_tcp_data_ready(struct sock *sk, int bytes) +static void xs_tcp_data_ready(struct sock *sk) { struct rpc_xprt *xprt; read_descriptor_t rd_desc; -- cgit v1.2.3-58-ga151