diff options
| author | Jakub Kicinski <kuba@kernel.org> | 2026-04-27 12:06:06 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-04-28 17:43:32 -0700 |
| commit | b89769f936a8fa9e66de72ddc1b71a9745a488e6 (patch) | |
| tree | 490816c0380f1e23f37a44f4f08cc298335d9e2c | |
| parent | 67d7ae3340cae0a18ec1d53a2fce198c31a211b8 (diff) | |
net: psp: check for device unregister when creating assoc
psp_assoc_device_get_locked() obtains a psp_dev reference via
psp_dev_get_for_sock() (which uses psp_dev_tryget() under RCU);
it then acquires psd->lock and drops the reference. Before
the lock is taken, psp_dev_unregister() can run to completion:
take psd->lock, clear out state, unlock, drop the registration
reference.
The expectation is that the lock prevents device unregistration,
but much like with netdevs special care has to be taken when
"upgrading" a reference to a locked device. Add the missing
check if device is still alive. psp_dev_is_registered() exists
already but had no callers, which makes me wonder if I either
forgot to add this or lost the check during refactoring...
Reported-by: Yiming Qian <yimingqian591@gmail.com>
Fixes: 6b46ca260e22 ("net: psp: add socket security association code")
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20260427190606.366101-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/psp/psp_nl.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/net/psp/psp_nl.c b/net/psp/psp_nl.c index 6afd7707ec12..0cc744a6e1c9 100644 --- a/net/psp/psp_nl.c +++ b/net/psp/psp_nl.c @@ -305,8 +305,13 @@ int psp_assoc_device_get_locked(const struct genl_split_ops *ops, psd = psp_dev_get_for_sock(socket->sk); if (psd) { - err = psp_dev_check_access(psd, genl_info_net(info)); - if (err) { + /* Extra care needed here, psp_dev_get_for_sock() only gives + * us access to struct psp_dev's memory, which is quite weak. + */ + mutex_lock(&psd->lock); + if (!psp_dev_is_registered(psd) || + psp_dev_check_access(psd, genl_info_net(info))) { + mutex_unlock(&psd->lock); psp_dev_put(psd); psd = NULL; } @@ -319,7 +324,6 @@ int psp_assoc_device_get_locked(const struct genl_split_ops *ops, id = info->attrs[PSP_A_ASSOC_DEV_ID]; if (psd) { - mutex_lock(&psd->lock); if (id && psd->id != nla_get_u32(id)) { mutex_unlock(&psd->lock); NL_SET_ERR_MSG_ATTR(info->extack, id, |