net/colo: Fix a "double free" crash to clear the conn_list

We notice the QEMU may crash when the guest has too many
incoming network connections with the following log:

15197@1593578622.668573:colo_proxy_main : colo proxy connection hashtable full, clear it
free(): invalid pointer
[1]    15195 abort (core dumped)  qemu-system-x86_64 ....

This is because we create the s->connection_track_table with
g_hash_table_new_full() which is defined as:

GHashTable * g_hash_table_new_full (GHashFunc hash_func,
                       GEqualFunc key_equal_func,
                       GDestroyNotify key_destroy_func,
                       GDestroyNotify value_destroy_func);

The fourth parameter connection_destroy() will be called to free the
memory allocated for all 'Connection' values in the hashtable when
we call g_hash_table_remove_all() in the connection_hashtable_reset().

But both connection_track_table and conn_list reference to the same
conn instance. It will trigger double free in conn_list clear. So this
patch remove free action on hash table side to avoid double free the
conn.

Signed-off-by: Like Xu <like.xu@linux.intel.com>
Signed-off-by: Zhang Chen <chen.zhang@intel.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

diff --git a/net/colo-compare.c b/net/colo-compare.c
index d5d096580577cfdc2bf8b0392c4608c725bb95ec..787c740f1425a5c16d5e72160bf24b5942e2a515 100644 (file)
--- a/net/colo-compare.c
+++ b/net/colo-compare.c
@@ -1323,7 +1323,7 @@ static void colo_compare_complete(UserCreatable *uc, Error **errp)
     s->connection_track_table = g_hash_table_new_full(connection_key_hash,
                                                       connection_key_equal,
                                                       g_free,
-                                                      connection_destroy);
+                                                      NULL);
 
     colo_compare_iothread(s);
 

diff --git a/net/filter-rewriter.c b/net/filter-rewriter.c
index bf05023dc3c698341d4f8563c8484252b162926a..c18c4c20190176b620f462a4cf56705da81deaaf 100644 (file)
--- a/net/filter-rewriter.c
+++ b/net/filter-rewriter.c
@@ -383,7 +383,7 @@ static void colo_rewriter_setup(NetFilterState *nf, Error **errp)
     s->connection_track_table = g_hash_table_new_full(connection_key_hash,
                                                       connection_key_equal,
                                                       g_free,
-                                                      connection_destroy);
+                                                      NULL);
     s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf);
 }