tree af12df2727a1a1017e1667b108a76e38bfeea412
parent 0c8cd7f6bb8a53b244ecc498dc733204099b6cf3
author Guillaume Nault <gnault@redhat.com> 1575632329 +0100
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1576921347 +0100

tcp: Protect accesses to .ts_recent_stamp with {READ,WRITE}_ONCE()

[ Upstream commit 721c8dafad26ccfa90ff659ee19755e3377b829d ]

Syncookies borrow the ->rx_opt.ts_recent_stamp field to store the
timestamp of the last synflood. Protect them with READ_ONCE() and
WRITE_ONCE() since reads and writes aren't serialised.

Use of .rx_opt.ts_recent_stamp for storing the synflood timestamp was
introduced by a0f82f64e269 ("syncookies: remove last_synq_overflow from
struct tcp_sock"). But unprotected accesses were already there when
timestamp was stored in .last_synq_overflow.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>