From d58ff35122847a83ba55394e2ae3a1527b6febf5 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 16 Jun 2017 14:29:23 +0200 Subject: networking: make skb_push & __skb_push return void pointers It seems like a historic accident that these return unsigned char *, and in many places that means casts are required, more often than not. Make these functions return void * and remove all the casts across the tree, adding a (u8 *) cast only where the unsigned char pointer was used directly, all done with the following spatch: @@ expression SKB, LEN; typedef u8; identifier fn = { skb_push, __skb_push, skb_push_rcsum }; @@ - *(fn(SKB, LEN)) + *(u8 *)fn(SKB, LEN) @@ expression E, SKB, LEN; identifier fn = { skb_push, __skb_push, skb_push_rcsum }; type T; @@ - E = ((T *)(fn(SKB, LEN))) + E = fn(SKB, LEN) @@ expression SKB, LEN; identifier fn = { skb_push, __skb_push, skb_push_rcsum }; @@ - fn(SKB, LEN)[0] + *(u8 *)fn(SKB, LEN) Note that the last part there converts from push(...)[0] to the more idiomatic *(u8 *)push(...). Signed-off-by: Johannes Berg Signed-off-by: David S. Miller --- net/core/netpoll.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/core/netpoll.c') diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 29be2466970c..37c1e34ddd85 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -441,7 +441,7 @@ void netpoll_send_udp(struct netpoll *np, const char *msg, int len) ip6h->saddr = np->local_ip.in6; ip6h->daddr = np->remote_ip.in6; - eth = (struct ethhdr *) skb_push(skb, ETH_HLEN); + eth = skb_push(skb, ETH_HLEN); skb_reset_mac_header(skb); skb->protocol = eth->h_proto = htons(ETH_P_IPV6); } else { @@ -470,7 +470,7 @@ void netpoll_send_udp(struct netpoll *np, const char *msg, int len) put_unaligned(np->remote_ip.ip, &(iph->daddr)); iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); - eth = (struct ethhdr *) skb_push(skb, ETH_HLEN); + eth = skb_push(skb, ETH_HLEN); skb_reset_mac_header(skb); skb->protocol = eth->h_proto = htons(ETH_P_IP); } -- cgit v1.2.3 From 633547973ffc32fd2c815639d4675e1531f0896f Mon Sep 17 00:00:00 2001 From: "Reshetova, Elena" Date: Fri, 30 Jun 2017 13:07:58 +0300 Subject: net: convert sk_buff.users from atomic_t to refcount_t refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor Signed-off-by: David S. Miller --- net/core/netpoll.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/core/netpoll.c') diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 37c1e34ddd85..a835155c85f9 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -277,7 +277,7 @@ static void zap_completion_queue(void) struct sk_buff *skb = clist; clist = clist->next; if (!skb_irq_freeable(skb)) { - atomic_inc(&skb->users); + refcount_inc(&skb->users); dev_kfree_skb_any(skb); /* put this one back */ } else { __kfree_skb(skb); @@ -309,7 +309,7 @@ repeat: return NULL; } - atomic_set(&skb->users, 1); + refcount_set(&skb->users, 1); skb_reserve(skb, reserve); return skb; } -- cgit v1.2.3 From 433cea4d9bbb83cc848b80c51bb849a2ceb49379 Mon Sep 17 00:00:00 2001 From: "Reshetova, Elena" Date: Fri, 30 Jun 2017 13:08:04 +0300 Subject: net: convert netpoll_info.refcnt from atomic_t to refcount_t refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor Signed-off-by: David S. Miller --- net/core/netpoll.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'net/core/netpoll.c') diff --git a/net/core/netpoll.c b/net/core/netpoll.c index a835155c85f9..d3408a693166 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -632,7 +632,7 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev) skb_queue_head_init(&npinfo->txq); INIT_DELAYED_WORK(&npinfo->tx_work, queue_process); - atomic_set(&npinfo->refcnt, 1); + refcount_set(&npinfo->refcnt, 1); ops = np->dev->netdev_ops; if (ops->ndo_netpoll_setup) { @@ -642,7 +642,7 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev) } } else { npinfo = rtnl_dereference(ndev->npinfo); - atomic_inc(&npinfo->refcnt); + refcount_inc(&npinfo->refcnt); } npinfo->netpoll = np; @@ -821,7 +821,7 @@ void __netpoll_cleanup(struct netpoll *np) synchronize_srcu(&netpoll_srcu); - if (atomic_dec_and_test(&npinfo->refcnt)) { + if (refcount_dec_and_test(&npinfo->refcnt)) { const struct net_device_ops *ops; ops = np->dev->netdev_ops; -- cgit v1.2.3