diff options
| author | Namjae Jeon | 2026-02-09 10:43:19 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2026-03-13 17:20:30 +0100 |
| commit | 4c2ca31608521895dd742a43beca4b4d29762345 (patch) | |
| tree | e7e314bf279909d8a487cfe578e593546631fae5 /fs | |
| parent | c9c00b85b85b3c47c46ed9659f127cd2bf549ae0 (diff) | |
ksmbd: add chann_lock to protect ksmbd_chann_list xarray
[ Upstream commit 4f3a06cc57976cafa8c6f716646be6c79a99e485 ]
ksmbd_chann_list xarray lacks synchronization, allowing use-after-free in
multi-channel sessions (between lookup_chann_list() and ksmbd_chann_del).
Adds rw_semaphore chann_lock to struct ksmbd_session and protects
all xa_load/xa_store/xa_erase accesses.
Cc: stable@vger.kernel.org
Reported-by: Igor Stepansky <igor.stepansky@orca.security>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/smb/server/mgmt/user_session.c | 5 | ||||
| -rw-r--r-- | fs/smb/server/mgmt/user_session.h | 1 | ||||
| -rw-r--r-- | fs/smb/server/smb2pdu.c | 12 |
3 files changed, 17 insertions, 1 deletions
diff --git a/fs/smb/server/mgmt/user_session.c b/fs/smb/server/mgmt/user_session.c index 66198ed26aec..352cf9e47ebe 100644 --- a/fs/smb/server/mgmt/user_session.c +++ b/fs/smb/server/mgmt/user_session.c @@ -32,12 +32,14 @@ static void free_channel_list(struct ksmbd_session *sess) struct channel *chann; unsigned long index; + down_write(&sess->chann_lock); xa_for_each(&sess->ksmbd_chann_list, index, chann) { xa_erase(&sess->ksmbd_chann_list, index); kfree(chann); } xa_destroy(&sess->ksmbd_chann_list); + up_write(&sess->chann_lock); } static void __session_rpc_close(struct ksmbd_session *sess, @@ -220,7 +222,9 @@ static int ksmbd_chann_del(struct ksmbd_conn *conn, struct ksmbd_session *sess) { struct channel *chann; + down_write(&sess->chann_lock); chann = xa_erase(&sess->ksmbd_chann_list, (long)conn); + up_write(&sess->chann_lock); if (!chann) return -ENOENT; @@ -454,6 +458,7 @@ static struct ksmbd_session *__session_create(int protocol) rwlock_init(&sess->tree_conns_lock); atomic_set(&sess->refcnt, 2); init_rwsem(&sess->rpc_lock); + init_rwsem(&sess->chann_lock); ret = __init_smb2_session(sess); if (ret) diff --git a/fs/smb/server/mgmt/user_session.h b/fs/smb/server/mgmt/user_session.h index c5749d6ec715..cba7f688f6b5 100644 --- a/fs/smb/server/mgmt/user_session.h +++ b/fs/smb/server/mgmt/user_session.h @@ -49,6 +49,7 @@ struct ksmbd_session { char sess_key[CIFS_KEY_SIZE]; struct hlist_node hlist; + struct rw_semaphore chann_lock; struct xarray ksmbd_chann_list; struct xarray tree_conns; struct ida tree_conn_ida; diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index 8fa6ab9dfd07..0d7ba57c1ca6 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -78,7 +78,13 @@ static inline bool check_session_id(struct ksmbd_conn *conn, u64 id) struct channel *lookup_chann_list(struct ksmbd_session *sess, struct ksmbd_conn *conn) { - return xa_load(&sess->ksmbd_chann_list, (long)conn); + struct channel *chann; + + down_read(&sess->chann_lock); + chann = xa_load(&sess->ksmbd_chann_list, (long)conn); + up_read(&sess->chann_lock); + + return chann; } /** @@ -1560,8 +1566,10 @@ binding_session: return -ENOMEM; chann->conn = conn; + down_write(&sess->chann_lock); old = xa_store(&sess->ksmbd_chann_list, (long)conn, chann, KSMBD_DEFAULT_GFP); + up_write(&sess->chann_lock); if (xa_is_err(old)) { kfree(chann); return xa_err(old); @@ -1658,8 +1666,10 @@ binding_session: return -ENOMEM; chann->conn = conn; + down_write(&sess->chann_lock); old = xa_store(&sess->ksmbd_chann_list, (long)conn, chann, KSMBD_DEFAULT_GFP); + up_write(&sess->chann_lock); if (xa_is_err(old)) { kfree(chann); return xa_err(old); |