You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
59 lines
2.1 KiB
59 lines
2.1 KiB
From 970711fde95bee3de1e4a5e0b557c3132d0c3e3f Mon Sep 17 00:00:00 2001
|
|
From: =?UTF-8?q?Ond=C5=99ej=20Lyson=C4=9Bk?= <olysonek@redhat.com>
|
|
Date: Tue, 6 Feb 2018 11:39:01 +0100
|
|
Subject: [PATCH 59/59] Fix SEGFAULT when running in a container as PID 1
|
|
|
|
When vsftpd is running in a container as PID 1, it is possible
|
|
that it will get SIGCHILD for processes, which were not directly
|
|
created by it, but by some of its children. These processes will
|
|
not be in the s_p_pid_ip_hash hash table, and thus trying to
|
|
delete the entry from the hash table in standalone.c:handle_sigchld()
|
|
will result in segmentation fault.
|
|
|
|
I can quite easily reproduce it with the upstream vsftpd and default
|
|
configuration, except for isolate=NO and isolate_network=NO being set
|
|
(it seems to me that network namespaces take a long time to create
|
|
and destroy, which hides the race condition), on a quad-core machine.
|
|
When connecting to vsftpd in a loop like this:
|
|
$ while true; do echo -en '' | nc localhost 21; done
|
|
|
|
vsftpd crashes after a couple of seconds.
|
|
---
|
|
standalone.c | 18 +++++++++++++-----
|
|
1 file changed, 13 insertions(+), 5 deletions(-)
|
|
|
|
diff --git a/standalone.c b/standalone.c
|
|
index 3b65ea2..3f35e9e 100644
|
|
--- a/standalone.c
|
|
+++ b/standalone.c
|
|
@@ -270,13 +270,21 @@ handle_sigchld(void* duff)
|
|
if (reap_one)
|
|
{
|
|
struct vsf_sysutil_ipaddr* p_ip;
|
|
- /* Account total number of instances */
|
|
- --s_children;
|
|
- /* Account per-IP limit */
|
|
p_ip = (struct vsf_sysutil_ipaddr*)
|
|
hash_lookup_entry(s_p_pid_ip_hash, (void*)&reap_one);
|
|
- drop_ip_count(p_ip);
|
|
- hash_free_entry(s_p_pid_ip_hash, (void*)&reap_one);
|
|
+ /* If we are running in a container as PID 1, it is possible
|
|
+ * that we will get SIGCHILD for processes, which were not
|
|
+ * created directly by our process and which are not in the
|
|
+ * s_p_pid_ip_hash hash table.
|
|
+ */
|
|
+ if (p_ip)
|
|
+ {
|
|
+ /* Account total number of instances */
|
|
+ --s_children;
|
|
+ /* Account per-IP limit */
|
|
+ drop_ip_count(p_ip);
|
|
+ hash_free_entry(s_p_pid_ip_hash, (void*)&reap_one);
|
|
+ }
|
|
}
|
|
}
|
|
}
|
|
--
|
|
2.14.4
|
|
|