linux/net/dccp
Eric Dumazet b357a364c5 inet: fix possible panic in reqsk_queue_unlink()
[ 3897.923145] BUG: unable to handle kernel NULL pointer dereference at
 0000000000000080
[ 3897.931025] IP: [<ffffffffa9f27686>] reqsk_timer_handler+0x1a6/0x243

There is a race when reqsk_timer_handler() and tcp_check_req() call
inet_csk_reqsk_queue_unlink() on the same req at the same time.

Before commit fa76ce7328 ("inet: get rid of central tcp/dccp listener
timer"), listener spinlock was held and race could not happen.

To solve this bug, we change reqsk_queue_unlink() to not assume req
must be found, and we return a status, to conditionally release a
refcount on the request sock.

This also means tcp_check_req() in non fastopen case might or not
consume req refcount, so tcp_v6_hnd_req() & tcp_v4_hnd_req() have
to properly handle this.

(Same remark for dccp_check_req() and its callers)

inet_csk_reqsk_queue_drop() is now too big to be inlined, as it is
called 4 times in tcp and 3 times in dccp.

Fixes: fa76ce7328 ("inet: get rid of central tcp/dccp listener timer")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-04-24 11:39:15 -04:00
..
ccids dccp: re-enable debug macro 2014-02-16 23:45:00 -05:00
ackvec.c dccp: replace min/casting by min_t 2014-11-18 15:26:32 -05:00
ackvec.h net: dccp: Remove extern from function prototypes 2013-10-19 19:12:11 -04:00
ccid.c net/dccp/ccid.c: add __init to ccid_activate 2014-10-01 18:33:13 -04:00
ccid.h net: dccp: Remove extern from function prototypes 2013-10-19 19:12:11 -04:00
dccp.h ipv4: dccp: handle ICMP messages on DCCP_NEW_SYN_RECV request sockets 2015-03-23 16:52:26 -04:00
diag.c inet_diag: add const to inet_diag_req_v2 2015-03-10 13:45:28 -04:00
feat.c dccp: kerneldoc warning fixes 2014-11-18 15:26:31 -05:00
feat.h net: dccp: Remove extern from function prototypes 2013-10-19 19:12:11 -04:00
input.c dccp: spelling s/reseting/resetting 2014-11-18 15:26:32 -05:00
ipv4.c inet: fix possible panic in reqsk_queue_unlink() 2015-04-24 11:39:15 -04:00
ipv6.c inet: fix possible panic in reqsk_queue_unlink() 2015-04-24 11:39:15 -04:00
ipv6.h inet: includes a sock_common in request_sock 2013-10-10 00:08:07 -04:00
Kconfig net/dccp: remove depends on CONFIG_EXPERIMENTAL 2013-01-11 11:39:34 -08:00
Makefile
minisocks.c inet: fix possible panic in reqsk_queue_unlink() 2015-04-24 11:39:15 -04:00
options.c dccp: remove obsolete code 2014-01-04 20:18:49 -05:00
output.c ipv4: add a sock pointer to ip_queue_xmit() 2014-04-15 12:58:34 -04:00
probe.c net: Remove iocb argument from sendmsg and recvmsg 2015-03-02 13:06:31 -05:00
proto.c net: Remove iocb argument from sendmsg and recvmsg 2015-03-02 13:06:31 -05:00
qpolicy.c
sysctl.c dccp: make the request_retries minimum is 1 2014-05-14 15:34:16 -04:00
timer.c inet: get rid of central tcp/dccp listener timer 2015-03-20 12:40:25 -04:00