Changkun Ou created GUACAMOLE-608:
-------------------------------------
Summary: Daemon process may encounter dead loop
Key: GUACAMOLE-608
URL: https://issues.apache.org/jira/browse/GUACAMOLE-608
Project: Guacamole
Issue Type: Bug
Components: guacd
Affects Versions: 0.9.14
Reporter: Changkun Ou
`guacd` involves a `__write_all` function to write instruction to write as much
as possible, see
https://github.com/apache/guacamole-server/blob/7c191d7be0441a1cb64c90ab62d6535f3798eacb/src/guacd/connection.c#L67
However system call `write` may return 0 and set `errno`, which is not verified
in the function.
A possible case: `write` keeps return 0 and nothing writes to buffer, therefore
the daemon process encounters a dead loop, furthermore, it leads CPU rate up to
99%.
A possible fix is:
```
int written = write(fd, buffer, length);
if (written < 0)
return -1;
if (written == 0 && errno > 0)
return -1;
```
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
