linux/include/trace
David Howells 99f0eae653 rxrpc: Fix oops in tracepoint
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: a25e21f0bc ("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>
2019-07-02 15:29:57 -07:00
..
events rxrpc: Fix oops in tracepoint 2019-07-02 15:29:57 -07:00
bpf_probe.h bpf: add writable context for raw tracepoints 2019-04-26 19:04:19 -07:00
define_trace.h tracing: introduce TRACE_EVENT_NOP() 2019-04-08 09:22:51 -04:00
perf.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
syscall.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
trace_events.h tracing: Prevent further users of zero size static arrays in trace events 2018-05-29 08:29:13 -04:00