From a0a2a6602496a45ae838a96db8b8173794b5d398 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Tue, 4 Aug 2015 15:42:47 +0800 Subject: net: Fix skb_set_peeked use-after-free bug The commit 738ac1ebb96d02e0d23bc320302a6ea94c612dec ("net: Clone skb before setting peeked flag") introduced a use-after-free bug in skb_recv_datagram. This is because skb_set_peeked may create a new skb and free the existing one. As it stands the caller will continue to use the old freed skb. This patch fixes it by making skb_set_peeked return the new skb (or the old one if unchanged). Fixes: 738ac1ebb96d ("net: Clone skb before setting peeked flag") Reported-by: Brenden Blanco Signed-off-by: Herbert Xu Tested-by: Brenden Blanco Reviewed-by: Konstantin Khlebnikov Signed-off-by: David S. Miller --- net/core/datagram.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'net/core') diff --git a/net/core/datagram.c b/net/core/datagram.c index 4967262b2707..617088aee21d 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -131,12 +131,12 @@ out_noerr: goto out; } -static int skb_set_peeked(struct sk_buff *skb) +static struct sk_buff *skb_set_peeked(struct sk_buff *skb) { struct sk_buff *nskb; if (skb->peeked) - return 0; + return skb; /* We have to unshare an skb before modifying it. */ if (!skb_shared(skb)) @@ -144,7 +144,7 @@ static int skb_set_peeked(struct sk_buff *skb) nskb = skb_clone(skb, GFP_ATOMIC); if (!nskb) - return -ENOMEM; + return ERR_PTR(-ENOMEM); skb->prev->next = nskb; skb->next->prev = nskb; @@ -157,7 +157,7 @@ static int skb_set_peeked(struct sk_buff *skb) done: skb->peeked = 1; - return 0; + return skb; } /** @@ -229,8 +229,9 @@ struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned int flags, continue; } - error = skb_set_peeked(skb); - if (error) + skb = skb_set_peeked(skb); + error = PTR_ERR(skb); + if (IS_ERR(skb)) goto unlock_err; atomic_inc(&skb->users); -- cgit v1.2.3 From 7ba8bd75ddc6b041b5716dbb29e49df3e9cc2928 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 4 Aug 2015 18:33:34 +0200 Subject: net: pktgen: don't abuse current->state in pktgen_thread_worker() Commit 1fbe4b46caca "net: pktgen: kill the Wait for kthread_stop code in pktgen_thread_worker()" removed (in particular) the final __set_current_state(TASK_RUNNING) and I didn't notice the previous set_current_state(TASK_INTERRUPTIBLE). This triggers the warning in __might_sleep() after return. Afaics, we can simply remove both set_current_state()'s, and we could do this a long ago right after ef87979c273a2 "pktgen: better scheduler friendliness" which changed pktgen_thread_worker() to use wait_event_interruptible_timeout(). Reported-by: Huang Ying Signed-off-by: Oleg Nesterov Signed-off-by: David S. Miller --- net/core/pktgen.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'net/core') diff --git a/net/core/pktgen.c b/net/core/pktgen.c index 1ebdf1c0d118..1cbd209192ea 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -3514,8 +3514,6 @@ static int pktgen_thread_worker(void *arg) set_freezable(); - __set_current_state(TASK_RUNNING); - while (!kthread_should_stop()) { pkt_dev = next_to_run(t); @@ -3560,7 +3558,6 @@ static int pktgen_thread_worker(void *arg) try_to_freeze(); } - set_current_state(TASK_INTERRUPTIBLE); pr_debug("%s stopping all device\n", t->tsk->comm); pktgen_stop(t); -- cgit v1.2.3 From 2235f2ac75fd2501c251b0b699a9632e80239a6d Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 10 Aug 2015 09:09:13 -0700 Subject: inet: fix races with reqsk timers reqsk_queue_destroy() and reqsk_queue_unlink() should use del_timer_sync() instead of del_timer() before calling reqsk_put(), otherwise we could free a req still used by another cpu. But before doing so, reqsk_queue_destroy() must release syn_wait_lock spinlock or risk a dead lock, as reqsk_timer_handler() might need to take this same spinlock from reqsk_queue_unlink() (called from inet_csk_reqsk_queue_drop()) Fixes: fa76ce7328b2 ("inet: get rid of central tcp/dccp listener timer") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/request_sock.c | 8 +++++++- net/ipv4/inet_connection_sock.c | 2 +- 2 files changed, 8 insertions(+), 2 deletions(-) (limited to 'net/core') diff --git a/net/core/request_sock.c b/net/core/request_sock.c index 87b22c0bc08c..b42f0e26f89e 100644 --- a/net/core/request_sock.c +++ b/net/core/request_sock.c @@ -103,10 +103,16 @@ void reqsk_queue_destroy(struct request_sock_queue *queue) spin_lock_bh(&queue->syn_wait_lock); while ((req = lopt->syn_table[i]) != NULL) { lopt->syn_table[i] = req->dl_next; + /* Because of following del_timer_sync(), + * we must release the spinlock here + * or risk a dead lock. + */ + spin_unlock_bh(&queue->syn_wait_lock); atomic_inc(&lopt->qlen_dec); - if (del_timer(&req->rsk_timer)) + if (del_timer_sync(&req->rsk_timer)) reqsk_put(req); reqsk_put(req); + spin_lock_bh(&queue->syn_wait_lock); } spin_unlock_bh(&queue->syn_wait_lock); } diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 60021d0d9326..05e3145f7dc3 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -593,7 +593,7 @@ static bool reqsk_queue_unlink(struct request_sock_queue *queue, } spin_unlock(&queue->syn_wait_lock); - if (del_timer(&req->rsk_timer)) + if (del_timer_sync(&req->rsk_timer)) reqsk_put(req); return found; } -- cgit v1.2.3