4 ksmbd SMB3 server fixes, most also for stable

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Merge tag 'v6.15-rc5-ksmbd-server-fixes' of git://git.samba.org/ksmbd

Pull smb server fixes from Steve French:

 - Fix UAF closing file table (e.g. in tree disconnect)

 - Fix potential out of bounds write

 - Fix potential memory leak parsing lease state in open

 - Fix oops in rename with empty target

* tag 'v6.15-rc5-ksmbd-server-fixes' of git://git.samba.org/ksmbd:
  ksmbd: Fix UAF in __close_file_table_ids
  ksmbd: prevent out-of-bounds stream writes by validating *pos
  ksmbd: fix memory leak in parse_lease_state()
  ksmbd: prevent rename with empty string

fs/smb/server/oplock.c

@@ -1496,7 +1496,7 @@ struct lease_ctx_info *parse_lease_state(void *open_req)
 
 		if (le16_to_cpu(cc->DataOffset) + le32_to_cpu(cc->DataLength) <
 		    sizeof(struct create_lease_v2) - 4)
-			return NULL;
+			goto err_out;
 
 		memcpy(lreq->lease_key, lc->lcontext.LeaseKey, SMB2_LEASE_KEY_SIZE);
 		lreq->req_state = lc->lcontext.LeaseState;
@@ -1512,7 +1512,7 @@ struct lease_ctx_info *parse_lease_state(void *open_req)
 
 		if (le16_to_cpu(cc->DataOffset) + le32_to_cpu(cc->DataLength) <
 		    sizeof(struct create_lease))
-			return NULL;
+			goto err_out;
 
 		memcpy(lreq->lease_key, lc->lcontext.LeaseKey, SMB2_LEASE_KEY_SIZE);
 		lreq->req_state = lc->lcontext.LeaseState;
@@ -1521,6 +1521,9 @@ struct lease_ctx_info *parse_lease_state(void *open_req)
 		lreq->version = 1;
 	}
 	return lreq;
+err_out:
+	kfree(lreq);
+	return NULL;
 }
 
 /**

fs/smb/server/smb2pdu.c

@@ -633,6 +633,11 @@ smb2_get_name(const char *src, const int maxlen, struct nls_table *local_nls)
 		return name;
 	}
 
+	if (*name == '\0') {
+		kfree(name);
+		return ERR_PTR(-EINVAL);
+	}
+
 	if (*name == '\\') {
 		pr_err("not allow directory name included leading slash\n");
 		kfree(name);

fs/smb/server/vfs.c

@@ -426,6 +426,13 @@ static int ksmbd_vfs_stream_write(struct ksmbd_file *fp, char *buf, loff_t *pos,
 		goto out;
 	}
 
+	if (v_len <= *pos) {
+		pr_err("stream write position %lld is out of bounds (stream length: %zd)\n",
+				*pos, v_len);
+		err = -EINVAL;
+		goto out;
+	}
+
 	if (v_len < size) {
 		wbuf = kvzalloc(size, KSMBD_DEFAULT_GFP);
 		if (!wbuf) {

fs/smb/server/vfs_cache.c

@@ -661,21 +661,40 @@ __close_file_table_ids(struct ksmbd_file_table *ft,
 		       bool (*skip)(struct ksmbd_tree_connect *tcon,
 				    struct ksmbd_file *fp))
 {
-	unsigned int			id;
-	struct ksmbd_file		*fp;
-	int				num = 0;
+	struct ksmbd_file *fp;
+	unsigned int id = 0;
+	int num = 0;
 
-	idr_for_each_entry(ft->idr, fp, id) {
-		if (skip(tcon, fp))
+	while (1) {
+		write_lock(&ft->lock);
+		fp = idr_get_next(ft->idr, &id);
+		if (!fp) {
+			write_unlock(&ft->lock);
+			break;
+		}
+
+		if (skip(tcon, fp) ||
+		    !atomic_dec_and_test(&fp->refcount)) {
+			id++;
+			write_unlock(&ft->lock);
 			continue;
+		}
 
 		set_close_state_blocked_works(fp);
+		idr_remove(ft->idr, fp->volatile_id);
+		fp->volatile_id = KSMBD_NO_FID;
+		write_unlock(&ft->lock);
+
+		down_write(&fp->f_ci->m_lock);
+		list_del_init(&fp->node);
+		up_write(&fp->f_ci->m_lock);
 
-		if (!atomic_dec_and_test(&fp->refcount))
-			continue;
 		__ksmbd_close_fd(ft, fp);
+
 		num++;
+		id++;
 	}
+
 	return num;
 }