Four smb3 fixes for stable

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Merge tag '5.10-rc5-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs fixes from Steve French:
 "Four smb3 fixes for stable: one fixes a memleak, the other three
  address a problem found with decryption offload that can cause a use
  after free"

* tag '5.10-rc5-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  smb3: Handle error case during offload read path
  smb3: Avoid Mid pending list corruption
  smb3: Call cifs reconnect from demultiplex thread
  cifs: fix a memleak with modefromsid

fs/cifs/cifsacl.c

@@ -1266,6 +1266,7 @@ cifs_acl_to_fattr(struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr,
 		cifs_dbg(VFS, "%s: error %d getting sec desc\n", __func__, rc);
 	} else if (mode_from_special_sid) {
 		rc = parse_sec_desc(cifs_sb, pntsd, acllen, fattr, true);
+		kfree(pntsd);
 	} else {
 		/* get approximated mode from ACL */
 		rc = parse_sec_desc(cifs_sb, pntsd, acllen, fattr, false);

fs/cifs/smb2ops.c

@@ -264,7 +264,7 @@ smb2_revert_current_mid(struct TCP_Server_Info *server, const unsigned int val)
 }
 
 static struct mid_q_entry *
-smb2_find_mid(struct TCP_Server_Info *server, char *buf)
+__smb2_find_mid(struct TCP_Server_Info *server, char *buf, bool dequeue)
 {
 	struct mid_q_entry *mid;
 	struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)buf;
@@ -281,6 +281,10 @@ smb2_find_mid(struct TCP_Server_Info *server, char *buf)
 		    (mid->mid_state == MID_REQUEST_SUBMITTED) &&
 		    (mid->command == shdr->Command)) {
 			kref_get(&mid->refcount);
+			if (dequeue) {
+				list_del_init(&mid->qhead);
+				mid->mid_flags |= MID_DELETED;
+			}
 			spin_unlock(&GlobalMid_Lock);
 			return mid;
 		}
@@ -289,6 +293,18 @@ smb2_find_mid(struct TCP_Server_Info *server, char *buf)
 	return NULL;
 }
 
+static struct mid_q_entry *
+smb2_find_mid(struct TCP_Server_Info *server, char *buf)
+{
+	return __smb2_find_mid(server, buf, false);
+}
+
+static struct mid_q_entry *
+smb2_find_dequeue_mid(struct TCP_Server_Info *server, char *buf)
+{
+	return __smb2_find_mid(server, buf, true);
+}
+
 static void
 smb2_dump_detail(void *buf, struct TCP_Server_Info *server)
 {
@@ -4356,7 +4372,8 @@ init_read_bvec(struct page **pages, unsigned int npages, unsigned int data_size,
 static int
 handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
 		 char *buf, unsigned int buf_len, struct page **pages,
-		 unsigned int npages, unsigned int page_data_size)
+		 unsigned int npages, unsigned int page_data_size,
+		 bool is_offloaded)
 {
 	unsigned int data_offset;
 	unsigned int data_len;
@@ -4378,7 +4395,8 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
 
 	if (server->ops->is_session_expired &&
 	    server->ops->is_session_expired(buf)) {
-		cifs_reconnect(server);
+		if (!is_offloaded)
+			cifs_reconnect(server);
 		return -1;
 	}
 
@@ -4402,7 +4420,10 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
 		cifs_dbg(FYI, "%s: server returned error %d\n",
 			 __func__, rdata->result);
 		/* normal error on read response */
-		dequeue_mid(mid, false);
+		if (is_offloaded)
+			mid->mid_state = MID_RESPONSE_RECEIVED;
+		else
+			dequeue_mid(mid, false);
 		return 0;
 	}
 
@@ -4426,7 +4447,10 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
 		cifs_dbg(FYI, "%s: data offset (%u) beyond end of smallbuf\n",
 			 __func__, data_offset);
 		rdata->result = -EIO;
-		dequeue_mid(mid, rdata->result);
+		if (is_offloaded)
+			mid->mid_state = MID_RESPONSE_MALFORMED;
+		else
+			dequeue_mid(mid, rdata->result);
 		return 0;
 	}
 
@@ -4442,21 +4466,30 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
 			cifs_dbg(FYI, "%s: data offset (%u) beyond 1st page of response\n",
 				 __func__, data_offset);
 			rdata->result = -EIO;
-			dequeue_mid(mid, rdata->result);
+			if (is_offloaded)
+				mid->mid_state = MID_RESPONSE_MALFORMED;
+			else
+				dequeue_mid(mid, rdata->result);
 			return 0;
 		}
 
 		if (data_len > page_data_size - pad_len) {
 			/* data_len is corrupt -- discard frame */
 			rdata->result = -EIO;
-			dequeue_mid(mid, rdata->result);
+			if (is_offloaded)
+				mid->mid_state = MID_RESPONSE_MALFORMED;
+			else
+				dequeue_mid(mid, rdata->result);
 			return 0;
 		}
 
 		rdata->result = init_read_bvec(pages, npages, page_data_size,
 					       cur_off, &bvec);
 		if (rdata->result != 0) {
-			dequeue_mid(mid, rdata->result);
+			if (is_offloaded)
+				mid->mid_state = MID_RESPONSE_MALFORMED;
+			else
+				dequeue_mid(mid, rdata->result);
 			return 0;
 		}
 
@@ -4471,7 +4504,10 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
 		/* read response payload cannot be in both buf and pages */
 		WARN_ONCE(1, "buf can not contain only a part of read data");
 		rdata->result = -EIO;
-		dequeue_mid(mid, rdata->result);
+		if (is_offloaded)
+			mid->mid_state = MID_RESPONSE_MALFORMED;
+		else
+			dequeue_mid(mid, rdata->result);
 		return 0;
 	}
 
@@ -4482,7 +4518,10 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
 	if (length < 0)
 		return length;
 
-	dequeue_mid(mid, false);
+	if (is_offloaded)
+		mid->mid_state = MID_RESPONSE_RECEIVED;
+	else
+		dequeue_mid(mid, false);
 	return length;
 }
 
@@ -4511,15 +4550,34 @@ static void smb2_decrypt_offload(struct work_struct *work)
 	}
 
 	dw->server->lstrp = jiffies;
-	mid = smb2_find_mid(dw->server, dw->buf);
+	mid = smb2_find_dequeue_mid(dw->server, dw->buf);
 	if (mid == NULL)
 		cifs_dbg(FYI, "mid not found\n");
 	else {
 		mid->decrypted = true;
 		rc = handle_read_data(dw->server, mid, dw->buf,
 				      dw->server->vals->read_rsp_size,
-				      dw->ppages, dw->npages, dw->len);
+				      dw->ppages, dw->npages, dw->len,
-		mid->callback(mid);
+				      true);
+		if (rc >= 0) {
+#ifdef CONFIG_CIFS_STATS2
+			mid->when_received = jiffies;
+#endif
+			mid->callback(mid);
+		} else {
+			spin_lock(&GlobalMid_Lock);
+			if (dw->server->tcpStatus == CifsNeedReconnect) {
+				mid->mid_state = MID_RETRY_NEEDED;
+				spin_unlock(&GlobalMid_Lock);
+				mid->callback(mid);
+			} else {
+				mid->mid_state = MID_REQUEST_SUBMITTED;
+				mid->mid_flags &= ~(MID_DELETED);
+				list_add_tail(&mid->qhead,
+					&dw->server->pending_mid_q);
+				spin_unlock(&GlobalMid_Lock);
+			}
+		}
 		cifs_mid_q_entry_release(mid);
 	}
 
@@ -4622,7 +4680,7 @@ non_offloaded_decrypt:
 		(*mid)->decrypted = true;
 		rc = handle_read_data(server, *mid, buf,
 				      server->vals->read_rsp_size,
-				      pages, npages, len);
+				      pages, npages, len, false);
 	}
 
 free_pages:
@@ -4765,7 +4823,7 @@ smb3_handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 	char *buf = server->large_buf ? server->bigbuf : server->smallbuf;
 
 	return handle_read_data(server, mid, buf, server->pdu_size,
-				NULL, 0, 0);
+				NULL, 0, 0, false);
 }
 
 static int