diff options
author | David Howells <dhowells@redhat.com> | 2016-08-09 13:30:43 +0300 |
---|---|---|
committer | David Howells <dhowells@redhat.com> | 2016-08-09 19:13:55 +0300 |
commit | 50fd85a1f94753b86a7f540794dfd4f799e81ac2 (patch) | |
tree | c3d0c1d0a2ce49de1c77a3003188bc5243361916 | |
parent | 2e7e9758b2b680fa615d5cf70b7af416e96162d2 (diff) | |
download | linux-50fd85a1f94753b86a7f540794dfd4f799e81ac2.tar.xz |
rxrpc: Fix a use-after-push in data_ready handler
Fix a use of a packet after it has been enqueued onto the packet processing
queue in the data_ready handler. Once on a call's Rx queue, we mustn't
touch it any more as it may be dequeued and freed by the call processor
running on a work queue.
Save the values we need before enqueuing.
Without this, we can get an oops like the following:
BUG: unable to handle kernel NULL pointer dereference at 000000000000009c
IP: [<ffffffffa01854e8>] rxrpc_fast_process_packet+0x724/0xa11 [af_rxrpc]
PGD 0
Oops: 0000 [#1] SMP
Modules linked in: kafs(E) af_rxrpc(E) [last unloaded: af_rxrpc]
CPU: 2 PID: 0 Comm: swapper/2 Tainted: G E 4.7.0-fsdevel+ #1336
Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
task: ffff88040d6863c0 task.stack: ffff88040d68c000
RIP: 0010:[<ffffffffa01854e8>] [<ffffffffa01854e8>] rxrpc_fast_process_packet+0x724/0xa11 [af_rxrpc]
RSP: 0018:ffff88041fb03a78 EFLAGS: 00010246
RAX: ffffffffffffffff RBX: ffff8803ff195b00 RCX: 0000000000000001
RDX: ffffffffa01854d1 RSI: 0000000000000008 RDI: ffff8803ff195b00
RBP: ffff88041fb03ab0 R08: 0000000000000000 R09: 0000000000000001
R10: ffff88041fb038c8 R11: 0000000000000000 R12: ffff880406874800
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88041fb00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000009c CR3: 0000000001c14000 CR4: 00000000001406e0
Stack:
ffff8803ff195ea0 ffff880408348800 ffff880406874800 ffff8803ff195b00
ffff880408348800 ffff8803ff195ed8 0000000000000000 ffff88041fb03af0
ffffffffa0186072 0000000000000000 ffff8804054da000 0000000000000000
Call Trace:
<IRQ>
[<ffffffffa0186072>] rxrpc_data_ready+0x89d/0xbae [af_rxrpc]
[<ffffffff814c94d7>] __sock_queue_rcv_skb+0x24c/0x2b2
[<ffffffff8155c59a>] __udp_queue_rcv_skb+0x4b/0x1bd
[<ffffffff8155e048>] udp_queue_rcv_skb+0x281/0x4db
[<ffffffff8155ea8f>] __udp4_lib_rcv+0x7ed/0x963
[<ffffffff8155ef9a>] udp_rcv+0x15/0x17
[<ffffffff81531d86>] ip_local_deliver_finish+0x1c3/0x318
[<ffffffff81532544>] ip_local_deliver+0xbb/0xc4
[<ffffffff81531bc3>] ? inet_del_offload+0x40/0x40
[<ffffffff815322a9>] ip_rcv_finish+0x3ce/0x42c
[<ffffffff81532851>] ip_rcv+0x304/0x33d
[<ffffffff81531edb>] ? ip_local_deliver_finish+0x318/0x318
[<ffffffff814dff9d>] __netif_receive_skb_core+0x601/0x6e8
[<ffffffff814e072e>] __netif_receive_skb+0x13/0x54
[<ffffffff814e082a>] netif_receive_skb_internal+0xbb/0x17c
[<ffffffff814e1838>] napi_gro_receive+0xf9/0x1bd
[<ffffffff8144eb9f>] rtl8169_poll+0x32b/0x4a8
[<ffffffff814e1c7b>] net_rx_action+0xe8/0x357
[<ffffffff81051074>] __do_softirq+0x1aa/0x414
[<ffffffff810514ab>] irq_exit+0x3d/0xb0
[<ffffffff810184a2>] do_IRQ+0xe4/0xfc
[<ffffffff81612053>] common_interrupt+0x93/0x93
<EOI>
[<ffffffff814af837>] ? cpuidle_enter_state+0x1ad/0x2be
[<ffffffff814af832>] ? cpuidle_enter_state+0x1a8/0x2be
[<ffffffff814af96a>] cpuidle_enter+0x12/0x14
[<ffffffff8108956f>] call_cpuidle+0x39/0x3b
[<ffffffff81089855>] cpu_startup_entry+0x230/0x35d
[<ffffffff810312ea>] start_secondary+0xf4/0xf7
Signed-off-by: David Howells <dhowells@redhat.com>
-rw-r--r-- | net/rxrpc/input.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c index 04afdc09557b..789719031462 100644 --- a/net/rxrpc/input.c +++ b/net/rxrpc/input.c @@ -124,11 +124,15 @@ static int rxrpc_fast_process_data(struct rxrpc_call *call, struct rxrpc_skb_priv *sp; bool terminal; int ret, ackbit, ack; + u32 serial; + u8 flags; _enter("{%u,%u},,{%u}", call->rx_data_post, call->rx_first_oos, seq); sp = rxrpc_skb(skb); ASSERTCMP(sp->call, ==, NULL); + flags = sp->hdr.flags; + serial = sp->hdr.serial; spin_lock(&call->lock); @@ -192,8 +196,8 @@ static int rxrpc_fast_process_data(struct rxrpc_call *call, sp->call = call; rxrpc_get_call(call); atomic_inc(&call->skb_count); - terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) && - !(sp->hdr.flags & RXRPC_CLIENT_INITIATED)); + terminal = ((flags & RXRPC_LAST_PACKET) && + !(flags & RXRPC_CLIENT_INITIATED)); ret = rxrpc_queue_rcv_skb(call, skb, false, terminal); if (ret < 0) { if (ret == -ENOMEM || ret == -ENOBUFS) { @@ -205,12 +209,13 @@ static int rxrpc_fast_process_data(struct rxrpc_call *call, } skb = NULL; + sp = NULL; _debug("post #%u", seq); ASSERTCMP(call->rx_data_post, ==, seq); call->rx_data_post++; - if (sp->hdr.flags & RXRPC_LAST_PACKET) + if (flags & RXRPC_LAST_PACKET) set_bit(RXRPC_CALL_RCVD_LAST, &call->flags); /* if we've reached an out of sequence packet then we need to drain @@ -226,7 +231,7 @@ static int rxrpc_fast_process_data(struct rxrpc_call *call, spin_unlock(&call->lock); atomic_inc(&call->ackr_not_idle); - rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, sp->hdr.serial, false); + rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, serial, false); _leave(" = 0 [posted]"); return 0; @@ -239,7 +244,7 @@ out: discard_and_ack: _debug("discard and ACK packet %p", skb); - __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true); + __rxrpc_propose_ACK(call, ack, serial, true); discard: spin_unlock(&call->lock); rxrpc_free_skb(skb); @@ -247,7 +252,7 @@ discard: return 0; enqueue_and_ack: - __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true); + __rxrpc_propose_ACK(call, ack, serial, true); enqueue_packet: _net("defer skb %p", skb); spin_unlock(&call->lock); |