Merge tag 'ksmbd-for-7.3-rc2-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/smb

Pull smb server fixes from Namjae Jeon:

 - Fix a tree connection use-after-free in smb2_tree_connect() by
   balancing references across concurrent connect, disconnect, and
   session logoff paths.

 - Validate source and target ranges in COPYCHUNK requests before range
   locking and copy operations.

 - Fix an oplock break notification UAF by acquiring a connection
   reference under ksmbd_inode lock and releasing it after the
   notification work completes.

 - Fix the sparc build by using an unsigned int for the atomic work
   state, ensuring xchg() uses a supported four-byte operation.

* tag 'ksmbd-for-7.3-rc2-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/smb:
  ksmbd: fix tree connection use-after-free in smb2_tree_connect()
  ksmbd: validate COPYCHUNK source and target ranges
  ksmbd: fix use-after-free in oplock break notification
  ksmbd: fix sparc build with atomic work state

5 files changed, 90 insertions, 33 deletions

diff --git a/fs/smb/server/ksmbd_work.h b/fs/smb/server/ksmbd_work.h
index 5f1d3ebab4fb..0844aa929f55 100644
--- a/fs/smb/server/ksmbd_work.h
+++ b/fs/smb/server/ksmbd_work.h
@@ -82,7 +82,7 @@ struct ksmbd_work {
 	/* Contiguous SMB2 compression transform owned by this work item. */
 	void				*compress_buf;
 
-	unsigned char			state;
+	unsigned int			state;
 	/* No response for cancelled request */
 	bool                            send_no_response:1;
 	/* Request is encrypted */
diff --git a/fs/smb/server/mgmt/tree_connect.c b/fs/smb/server/mgmt/tree_connect.c
index 5f63e236267a..dd1db3554cae 100644
--- a/fs/smb/server/mgmt/tree_connect.c
+++ b/fs/smb/server/mgmt/tree_connect.c
@@ -82,6 +82,8 @@ ksmbd_tree_conn_connect(struct ksmbd_work *work, const char *share_name)
 	down_write(&sess->tree_conns_lock);
 	ret = xa_err(xa_store(&sess->tree_conns, tree_conn->id, tree_conn,
 			      KSMBD_DEFAULT_GFP));
+	if (!ret)
+		atomic_inc(&tree_conn->refcount);
 	up_write(&sess->tree_conns_lock);
 	if (ret) {
 		status.ret = -ENOMEM;
@@ -129,6 +131,12 @@ int ksmbd_tree_conn_disconnect(struct ksmbd_session *sess,
 			       struct ksmbd_tree_connect *tree_conn)
 {
 	down_write(&sess->tree_conns_lock);
+	if (tree_conn->t_state == TREE_DISCONNECTED ||
+	    xa_load(&sess->tree_conns, tree_conn->id) != tree_conn) {
+		up_write(&sess->tree_conns_lock);
+		return -ENOENT;
+	}
+	tree_conn->t_state = TREE_DISCONNECTED;
 	xa_erase(&sess->tree_conns, tree_conn->id);
 	up_write(&sess->tree_conns_lock);
 
diff --git a/fs/smb/server/oplock.c b/fs/smb/server/oplock.c
index 58af0fddf39f..1b8c3482d1e4 100644
--- a/fs/smb/server/oplock.c
+++ b/fs/smb/server/oplock.c
@@ -924,31 +924,69 @@ out:
 	ksmbd_conn_put(conn);
 }
 
+/*
+ * Select and pin the connection used for an oplock break before doing any
+ * allocations which may sleep.  The caller of oplock_break() holds a live
+ * reference on ci (a file being opened, a file being operated on, or an
+ * explicit ksmbd_inode_lookup_lock() reference in the parent lease break
+ * paths), so the inode cannot be freed during the call and its lock is
+ * reachable without dereferencing opinfo->o_fp, which is not pinned by
+ * the oplock reference and may be freed by a concurrent close.
+ *
+ * opinfo->conn is cleared under ci->m_lock by session_fd_check() when the
+ * durable handle owning the oplock is disconnected, reassigned by
+ * ksmbd_reopen_durable_fd() under the same lock, and the last
+ * ksmbd_conn_put() of the old connection frees it.  Holding the read lock
+ * excludes both writers, so the connection cannot be freed while it is
+ * selected.
+ */
+static struct ksmbd_conn *smb2_oplock_break_conn_get(struct oplock_info *opinfo,
+						     struct ksmbd_inode *ci)
+{
+	struct ksmbd_conn *conn;
+
+	down_read(&ci->m_lock);
+	conn = READ_ONCE(opinfo->conn);
+	if (conn && !ksmbd_conn_releasing(conn))
+		conn = ksmbd_conn_get(conn);
+	else
+		conn = NULL;
+	up_read(&ci->m_lock);
+
+	return conn;
+}
+
 /**
  * smb2_oplock_break_noti() - send smb2 exclusive/batch to level2 oplock
  *		break command from server to client
  * @opinfo:		oplock info object
+ * @ci:		inode owning the break target's oplock list, pinned by
+ *		the caller
  *
  * Return:      0 on success, otherwise error
  */
-static int smb2_oplock_break_noti(struct oplock_info *opinfo)
+static int smb2_oplock_break_noti(struct oplock_info *opinfo,
+				  struct ksmbd_inode *ci)
 {
 	struct ksmbd_conn *conn;
 	struct oplock_break_info *br_info;
 	int ret = 0;
 	struct ksmbd_work *work;
 
-	conn = READ_ONCE(opinfo->conn);
+	conn = smb2_oplock_break_conn_get(opinfo, ci);
 	if (!conn)
 		return ksmbd_invalidate_durable_fd(opinfo->fid);
 
 	work = ksmbd_alloc_work_struct();
-	if (!work)
+	if (!work) {
+		ksmbd_conn_put(conn);
 		return -ENOMEM;
+	}
 
 	br_info = kmalloc_obj(struct oplock_break_info, KSMBD_DEFAULT_GFP);
 	if (!br_info) {
 		ksmbd_free_work_struct(work);
+		ksmbd_conn_put(conn);
 		return -ENOMEM;
 	}
 
@@ -957,7 +995,8 @@ static int smb2_oplock_break_noti(struct oplock_info *opinfo)
 	br_info->open_trunc = opinfo->open_trunc;
 
 	work->request_buf = (char *)br_info;
-	work->conn = ksmbd_conn_get(conn);
+	/* Transfer the reference acquired by smb2_oplock_break_conn_get(). */
+	work->conn = conn;
 	work->sess = opinfo->sess;
 
 	ksmbd_conn_r_count_inc(conn);
@@ -1154,9 +1193,9 @@ static void wait_lease_breaking(struct oplock_info *opinfo)
 	}
 }
 
-static int oplock_break(struct oplock_info *brk_opinfo, int req_op_level,
-			struct ksmbd_work *in_work, bool share_break,
-			bool sync_lease_break)
+static int oplock_break(struct oplock_info *brk_opinfo, struct ksmbd_inode *ci,
+			int req_op_level, struct ksmbd_work *in_work,
+			bool share_break, bool sync_lease_break)
 {
 	int err = 0;
 	bool sent_interim = false;
@@ -1298,7 +1337,7 @@ again:
 		}
 	}
 
-	err = smb2_oplock_break_noti(brk_opinfo);
+	err = smb2_oplock_break_noti(brk_opinfo, ci);
 
 	ksmbd_debug(OPLOCK, "oplock granted = %d\n", brk_opinfo->level);
 	if (brk_opinfo->op_state == OPLOCK_CLOSING)
@@ -1326,13 +1365,14 @@ static int oplock_break_add(struct list_head *head, struct oplock_info *opinfo)
 	return 0;
 }
 
-static void oplock_break_drain_none(struct list_head *head)
+static void oplock_break_drain_none(struct list_head *head,
+				    struct ksmbd_inode *ci)
 {
 	struct oplock_break_entry *ent, *tmp;
 
 	list_for_each_entry_safe(ent, tmp, head, list) {
-		oplock_break(ent->opinfo, SMB2_OPLOCK_LEVEL_NONE, NULL, false,
-			     false);
+		oplock_break(ent->opinfo, ci, SMB2_OPLOCK_LEVEL_NONE, NULL,
+			     false, false);
 		list_del(&ent->list);
 		opinfo_put(ent->opinfo);
 		kfree(ent);
@@ -1481,7 +1521,7 @@ void smb_send_parent_lease_break_noti(struct ksmbd_file *fp,
 	}
 	up_read(&p_ci->m_lock);
 
-	oplock_break_drain_none(&brk_list);
+	oplock_break_drain_none(&brk_list, p_ci);
 
 	ksmbd_inode_put(p_ci);
 }
@@ -1525,7 +1565,7 @@ void smb_lazy_parent_lease_break_close(struct ksmbd_file *fp)
 	}
 	up_read(&p_ci->m_lock);
 
-	oplock_break_drain_none(&brk_list);
+	oplock_break_drain_none(&brk_list, p_ci);
 
 	ksmbd_inode_put(p_ci);
 }
@@ -1665,7 +1705,7 @@ int smb_grant_oplock(struct ksmbd_work *work, int req_op_level, u64 pid,
 	prev_durable_detached = prev_op_snapshot.durable_detached;
 	prev_fid = prev_op_snapshot.fid;
 
-	err = oplock_break(prev_opinfo, break_level, work,
+	err = oplock_break(prev_opinfo, ci, break_level, work,
 			   share_ret < 0 && prev_opinfo->is_lease, false);
 	if (prev_durable_detached || (prev_durable_open && err == -ENOENT))
 		ksmbd_invalidate_durable_fd(prev_fid);
@@ -1771,7 +1811,8 @@ static bool smb_break_all_write_oplock(struct ksmbd_work *work,
 	}
 
 	brk_opinfo->open_trunc = is_trunc;
-	oplock_break(brk_opinfo, SMB2_OPLOCK_LEVEL_II, work, false, false);
+	oplock_break(brk_opinfo, fp->f_ci, SMB2_OPLOCK_LEVEL_II, work, false,
+		     false);
 	sent_break = true;
 	opinfo_put(brk_opinfo);
 
@@ -1863,7 +1904,7 @@ next:
 				brk_op->op_state = OPLOCK_STATE_NONE;
 			spin_unlock(&brk_op->state_lock);
 		} else {
-			oplock_break(brk_op,
+			oplock_break(brk_op, ci,
 				     brk_op->is_lease && !is_trunc ?
 				     SMB2_OPLOCK_LEVEL_II : SMB2_OPLOCK_LEVEL_NONE,
 				     send_interim && !sent_interim ? work : NULL,
diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index d656832d82ef..0ecc52fde69c 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -2790,6 +2790,7 @@ int smb2_tree_connect(struct ksmbd_work *work)
 	struct ksmbd_session *sess = work->sess;
 	char *treename = NULL, *name = NULL;
 	struct ksmbd_tree_conn_status status;
+	struct ksmbd_tree_connect *tree_conn = NULL;
 	struct ksmbd_share_config *share = NULL;
 	int rc = -EINVAL;
 
@@ -2817,6 +2818,7 @@ int smb2_tree_connect(struct ksmbd_work *work)
 
 	status = ksmbd_tree_conn_connect(work, name);
 	if (status.ret == KSMBD_TREE_CONN_STATUS_OK) {
+		tree_conn = status.tree_conn;
 		rsp->hdr.Id.SyncId.TreeId = cpu_to_le32(status.tree_conn->id);
 		share = status.tree_conn->share_conf;
 
@@ -2860,8 +2862,15 @@ int smb2_tree_connect(struct ksmbd_work *work)
 		status.tree_conn->posix_extensions = true;
 
 	down_write(&sess->tree_conns_lock);
-	status.tree_conn->t_state = TREE_CONNECTED;
+	if (status.tree_conn->t_state == TREE_DISCONNECTED) {
+		status.ret = KSMBD_TREE_CONN_STATUS_ERROR;
+		share = NULL;
+	} else {
+		status.tree_conn->t_state = TREE_CONNECTED;
+	}
 	up_write(&sess->tree_conns_lock);
+	if (status.ret != KSMBD_TREE_CONN_STATUS_OK)
+		goto out_err1;
 	rsp->StructureSize = cpu_to_le16(16);
 out_err1:
 	/*
@@ -2888,9 +2897,6 @@ out_err1:
 	rc = ksmbd_iov_pin_rsp(work, rsp, sizeof(struct smb2_tree_connect_rsp));
 	if (rc) {
 		if (status.ret == KSMBD_TREE_CONN_STATUS_OK) {
-			down_write(&sess->tree_conns_lock);
-			status.tree_conn->t_state = TREE_DISCONNECTED;
-			up_write(&sess->tree_conns_lock);
 			ksmbd_tree_conn_disconnect(sess, status.tree_conn);
 			status.tree_conn = NULL;
 		}
@@ -2931,6 +2937,9 @@ out_err1:
 	if (status.ret != KSMBD_TREE_CONN_STATUS_OK)
 		smb2_set_err_rsp(work);
 
+	if (tree_conn)
+		ksmbd_tree_connect_put(tree_conn);
+
 	return rc;
 }
 
@@ -3034,17 +3043,6 @@ int smb2_tree_disconnect(struct ksmbd_work *work)
 
 	ksmbd_close_tree_conn_fds(work);
 
-	down_write(&sess->tree_conns_lock);
-	if (tcon->t_state == TREE_DISCONNECTED) {
-		up_write(&sess->tree_conns_lock);
-		rsp->hdr.Status = STATUS_NETWORK_NAME_DELETED;
-		err = -ENOENT;
-		goto err_out;
-	}
-
-	tcon->t_state = TREE_DISCONNECTED;
-	up_write(&sess->tree_conns_lock);
-
 	err = ksmbd_tree_conn_disconnect(sess, tcon);
 	if (err) {
 		rsp->hdr.Status = STATUS_NETWORK_NAME_DELETED;
diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c
index d2b524f79cbe..c2c9aaa5de1b 100644
--- a/fs/smb/server/vfs.c
+++ b/fs/smb/server/vfs.c
@@ -2007,6 +2007,11 @@ out:
 	return ret;
 }
 
+static bool ksmbd_vfs_copy_range_valid(loff_t offset, size_t len)
+{
+	return offset >= 0 && (loff_t)len <= MAX_LFS_FILESIZE - offset;
+}
+
 int ksmbd_vfs_copy_file_ranges(struct ksmbd_work *work,
 			       struct ksmbd_file *src_fp,
 			       struct ksmbd_file *dst_fp,
@@ -2042,6 +2047,10 @@ int ksmbd_vfs_copy_file_ranges(struct ksmbd_work *work,
 			dst_off = le64_to_cpu(chunks[i].TargetOffset);
 			len = le32_to_cpu(chunks[i].Length);
 
+			if (!ksmbd_vfs_copy_range_valid(src_off, len) ||
+			    !ksmbd_vfs_copy_range_valid(dst_off, len))
+				return -E2BIG;
+
 			if (check_lock_range(src_fp->filp, src_off,
 					     src_off + len - 1, READ))
 				return -EAGAIN;
@@ -2134,7 +2143,8 @@ int ksmbd_vfs_copy_file_ranges(struct ksmbd_work *work,
 		len = le32_to_cpu(chunks[i].Length);
 		copy_len = len;
 
-		if (src_off < 0)
+		if (!ksmbd_vfs_copy_range_valid(src_off, len) ||
+		    !ksmbd_vfs_copy_range_valid(dst_off, len))
 			return -E2BIG;
 
 		if (src_off > src_file_size || len > src_file_size - src_off) {