diff options
| author | Jakub Sitnicki <jakub@cloudflare.com> | 2022-11-14 20:16:19 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-11-16 12:52:19 +0000 |
| commit | b68777d54fac21fc833ec26ea1a2a84f975ab035 (patch) | |
| tree | bec75eaab58993c3245ac6d77c350f0b809e00b4 /include/net | |
| parent | f524b7289bbb0c8ffaa2ba3c34c146e43da54fb2 (diff) | |
l2tp: Serialize access to sk_user_data with sk_callback_lock
sk->sk_user_data has multiple users, which are not compatible with each
other. Writers must synchronize by grabbing the sk->sk_callback_lock.
l2tp currently fails to grab the lock when modifying the underlying tunnel
socket fields. Fix it by adding appropriate locking.
We err on the side of safety and grab the sk_callback_lock also inside the
sk_destruct callback overridden by l2tp, even though there should be no
refs allowing access to the sock at the time when sk_destruct gets called.
v4:
- serialize write to sk_user_data in l2tp sk_destruct
v3:
- switch from sock lock to sk_callback_lock
- document write-protection for sk_user_data
v2:
- update Fixes to point to origin of the bug
- use real names in Reported/Tested-by tags
Cc: Tom Parkin <tparkin@katalix.com>
Fixes: 3557baabf280 ("[L2TP]: PPP over L2TP driver core")
Reported-by: Haowei Yan <g1042620637@gmail.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
| -rw-r--r-- | include/net/sock.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index 5db02546941c..e0517ecc6531 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -323,7 +323,7 @@ struct sk_filter; * @sk_tskey: counter to disambiguate concurrent tstamp requests * @sk_zckey: counter to order MSG_ZEROCOPY notifications * @sk_socket: Identd and reporting IO signals - * @sk_user_data: RPC layer private data + * @sk_user_data: RPC layer private data. Write-protected by @sk_callback_lock. * @sk_frag: cached page frag * @sk_peek_off: current peek_offset value * @sk_send_head: front of stuff to transmit |