linux/net/dccp
Eric Dumazet 6bd4f355df ipv6: kill sk_dst_lock
While testing the np->opt RCU conversion, I found that UDP/IPv6 was
using a mixture of xchg() and sk_dst_lock to protect concurrent changes
to sk->sk_dst_cache, leading to possible corruptions and crashes.

ip6_sk_dst_lookup_flow() uses sk_dst_check() anyway, so the simplest
way to fix the mess is to remove sk_dst_lock completely, as we did for
IPv4.

__ip6_dst_store() and ip6_dst_store() share same implementation.

sk_setup_caps() being called with socket lock being held or not,
we have to use sk_dst_set() instead of __sk_dst_set()

Note that I had to move the "np->dst_cookie = rt6_get_cookie(rt);"
in ip6_dst_store() before the sk_setup_caps(sk, dst) call.

This is because ip6_dst_store() can be called from process context,
without any lock held.

As soon as the dst is installed in sk->sk_dst_cache, dst can be freed
from another cpu doing a concurrent ip6_dst_store()

Doing the dst dereference before doing the install is needed to make
sure no use after free would trigger.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-03 11:32:06 -05:00
..
ccids
ackvec.c dccp: drop null test before destroy functions 2015-09-15 16:49:43 -07:00
ackvec.h
ccid.c dccp: drop null test before destroy functions 2015-09-15 16:49:43 -07:00
ccid.h
dccp.h tcp/dccp: fix hashdance race for passive sessions 2015-10-23 05:42:21 -07:00
diag.c sock_diag: specify info_size per inet protocol 2015-06-15 19:49:22 -07:00
feat.c
feat.h
input.c
ipv4.c tcp/dccp: fix hashdance race for passive sessions 2015-10-23 05:42:21 -07:00
ipv6.c ipv6: kill sk_dst_lock 2015-12-03 11:32:06 -05:00
ipv6.h
Kconfig
Makefile
minisocks.c tcp/dccp: fix hashdance race for passive sessions 2015-10-23 05:42:21 -07:00
options.c
output.c dccp: constify dccp_make_response() socket argument 2015-09-25 13:00:39 -07:00
probe.c Use 64-bit timekeeping 2015-11-01 17:01:16 -05:00
proto.c net: rename SOCK_ASYNC_NOSPACE and SOCK_ASYNC_WAITDATA 2015-12-01 15:45:05 -05:00
qpolicy.c
sysctl.c
timer.c inet: get rid of central tcp/dccp listener timer 2015-03-20 12:40:25 -04:00