From 9d410c796067686b1e032d54ce475b7055537138 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 30 Oct 2009 05:03:53 +0000 Subject: [PATCH] net: fix sk_forward_alloc corruption On UDP sockets, we must call skb_free_datagram() with socket locked, or risk sk_forward_alloc corruption. This requirement is not respected in SUNRPC. Add a convenient helper, skb_free_datagram_locked() and use it in SUNRPC Reported-by: Francis Moreau Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/linux/skbuff.h | 2 ++ net/core/datagram.c | 10 +++++++++- net/ipv4/udp.c | 4 +--- net/ipv6/udp.c | 4 +--- net/sunrpc/svcsock.c | 10 +++++----- 5 files changed, 18 insertions(+), 12 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 6aebfceca3eb..bcdd6606f468 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1757,6 +1757,8 @@ extern int skb_copy_datagram_const_iovec(const struct sk_buff *from, int to_offset, int size); extern void skb_free_datagram(struct sock *sk, struct sk_buff *skb); +extern void skb_free_datagram_locked(struct sock *sk, + struct sk_buff *skb); extern int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags); extern __wsum skb_checksum(const struct sk_buff *skb, int offset, diff --git a/net/core/datagram.c b/net/core/datagram.c index 1c6cf3a1a4f6..4ade3011bb3c 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -224,6 +224,15 @@ void skb_free_datagram(struct sock *sk, struct sk_buff *skb) consume_skb(skb); sk_mem_reclaim_partial(sk); } +EXPORT_SYMBOL(skb_free_datagram); + +void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb) +{ + lock_sock(sk); + skb_free_datagram(sk, skb); + release_sock(sk); +} +EXPORT_SYMBOL(skb_free_datagram_locked); /** * skb_kill_datagram - Free a datagram skbuff forcibly @@ -752,5 +761,4 @@ unsigned int datagram_poll(struct file *file, struct socket *sock, EXPORT_SYMBOL(datagram_poll); EXPORT_SYMBOL(skb_copy_and_csum_datagram_iovec); EXPORT_SYMBOL(skb_copy_datagram_iovec); -EXPORT_SYMBOL(skb_free_datagram); EXPORT_SYMBOL(skb_recv_datagram); diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index d0d436d6216c..0fa9f70e4b19 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -999,9 +999,7 @@ try_again: err = ulen; out_free: - lock_sock(sk); - skb_free_datagram(sk, skb); - release_sock(sk); + skb_free_datagram_locked(sk, skb); out: return err; diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 3a60f12b34ed..cf538ed5ef6a 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -288,9 +288,7 @@ try_again: err = ulen; out_free: - lock_sock(sk); - skb_free_datagram(sk, skb); - release_sock(sk); + skb_free_datagram_locked(sk, skb); out: return err; diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index ccc5e83cae5d..1c246a4f491e 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -111,7 +111,7 @@ static void svc_release_skb(struct svc_rqst *rqstp) rqstp->rq_xprt_ctxt = NULL; dprintk("svc: service %p, releasing skb %p\n", rqstp, skb); - skb_free_datagram(svsk->sk_sk, skb); + skb_free_datagram_locked(svsk->sk_sk, skb); } } @@ -578,7 +578,7 @@ static int svc_udp_recvfrom(struct svc_rqst *rqstp) "svc: received unknown control message %d/%d; " "dropping RPC reply datagram\n", cmh->cmsg_level, cmh->cmsg_type); - skb_free_datagram(svsk->sk_sk, skb); + skb_free_datagram_locked(svsk->sk_sk, skb); return 0; } @@ -588,18 +588,18 @@ static int svc_udp_recvfrom(struct svc_rqst *rqstp) if (csum_partial_copy_to_xdr(&rqstp->rq_arg, skb)) { local_bh_enable(); /* checksum error */ - skb_free_datagram(svsk->sk_sk, skb); + skb_free_datagram_locked(svsk->sk_sk, skb); return 0; } local_bh_enable(); - skb_free_datagram(svsk->sk_sk, skb); + skb_free_datagram_locked(svsk->sk_sk, skb); } else { /* we can use it in-place */ rqstp->rq_arg.head[0].iov_base = skb->data + sizeof(struct udphdr); rqstp->rq_arg.head[0].iov_len = len; if (skb_checksum_complete(skb)) { - skb_free_datagram(svsk->sk_sk, skb); + skb_free_datagram_locked(svsk->sk_sk, skb); return 0; } rqstp->rq_xprt_ctxt = skb;