From: David Howells dhowells@redhat.com
[ Upstream commit 99f0eae653b2db64917d0b58099eb51e300b311d ]
If the rxrpc_eproto tracepoint is enabled, an oops will be cause by the trace line that rxrpc_extract_header() tries to emit when a protocol error occurs (typically because the packet is short) because the call argument is NULL.
Fix this by using ?: to assume 0 as the debug_id if call is NULL.
This can then be induced by:
echo -e '\0\0\0\0\0\0\0\0' | ncat -4u --send-only <addr> 20001
where addr has the following program running on it:
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <arpa/inet.h> #include <linux/rxrpc.h> int main(void) { struct sockaddr_rxrpc srx; int fd; memset(&srx, 0, sizeof(srx)); srx.srx_family = AF_RXRPC; srx.srx_service = 0; srx.transport_type = AF_INET; srx.transport_len = sizeof(srx.transport.sin); srx.transport.sin.sin_family = AF_INET; srx.transport.sin.sin_port = htons(0x4e21); fd = socket(AF_RXRPC, SOCK_DGRAM, AF_INET6); bind(fd, (struct sockaddr *)&srx, sizeof(srx)); sleep(20); return 0; }
It results in the following oops.
BUG: kernel NULL pointer dereference, address: 0000000000000340 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page ... RIP: 0010:trace_event_raw_event_rxrpc_rx_eproto+0x47/0xac ... Call Trace: <IRQ> rxrpc_extract_header+0x86/0x171 ? rcu_read_lock_sched_held+0x5d/0x63 ? rxrpc_new_skb+0xd4/0x109 rxrpc_input_packet+0xef/0x14fc ? rxrpc_input_data+0x986/0x986 udp_queue_rcv_one_skb+0xbf/0x3d0 udp_unicast_rcv_skb.isra.8+0x64/0x71 ip_protocol_deliver_rcu+0xe4/0x1b4 ip_local_deliver+0xf0/0x154 __netif_receive_skb_one_core+0x50/0x6c netif_receive_skb_internal+0x26b/0x2e9 napi_gro_receive+0xf8/0x1da rtl8169_poll+0x303/0x4c4 net_rx_action+0x10e/0x333 __do_softirq+0x1a5/0x38f irq_exit+0x54/0xc4 do_IRQ+0xda/0xf8 common_interrupt+0xf/0xf </IRQ> ... ? cpuidle_enter_state+0x23c/0x34d cpuidle_enter+0x2a/0x36 do_idle+0x163/0x1ea cpu_startup_entry+0x1d/0x1f start_secondary+0x157/0x172 secondary_startup_64+0xa4/0xb0
Fixes: a25e21f0bcd2 ("rxrpc, afs: Use debug_ids rather than pointers in traces") Signed-off-by: David Howells dhowells@redhat.com Reviewed-by: Marc Dionne marc.dionne@auristor.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- include/trace/events/rxrpc.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h index 6d182746afab..147546e0c11b 100644 --- a/include/trace/events/rxrpc.h +++ b/include/trace/events/rxrpc.h @@ -1381,7 +1381,7 @@ TRACE_EVENT(rxrpc_rx_eproto, ),
TP_fast_assign( - __entry->call = call->debug_id; + __entry->call = call ? call->debug_id : 0; __entry->serial = serial; __entry->why = why; ),