diff options
| author | Xin Long <lucien.xin@gmail.com> | 2022-11-18 22:45:01 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-11-22 05:45:24 +0100 |
| commit | a7b42969d63f47320853a802efd879fbdc4e010e (patch) | |
| tree | 7783a039437196000a9f7497af45c7617abb481e /net/tipc | |
| parent | tipc: set con sock in tipc_conn_alloc (diff) | |
| download | linux-a7b42969d63f47320853a802efd879fbdc4e010e.tar.xz linux-a7b42969d63f47320853a802efd879fbdc4e010e.zip | |
tipc: add an extra conn_get in tipc_conn_alloc
One extra conn_get() is needed in tipc_conn_alloc(), as after
tipc_conn_alloc() is called, tipc_conn_close() may free this
con before deferencing it in tipc_topsrv_accept():
tipc_conn_alloc();
newsk = newsock->sk;
<---- tipc_conn_close();
write_lock_bh(&sk->sk_callback_lock);
newsk->sk_data_ready = tipc_conn_data_ready;
Then an uaf issue can be triggered:
BUG: KASAN: use-after-free in tipc_topsrv_accept+0x1e7/0x370 [tipc]
Call Trace:
<TASK>
dump_stack_lvl+0x33/0x46
print_report+0x178/0x4b0
kasan_report+0x8c/0x100
kasan_check_range+0x179/0x1e0
tipc_topsrv_accept+0x1e7/0x370 [tipc]
process_one_work+0x6a3/0x1030
worker_thread+0x8a/0xdf0
This patch fixes it by holding it in tipc_conn_alloc(), then after
all accessing in tipc_topsrv_accept() releasing it. Note when does
this in tipc_topsrv_kern_subscr(), as tipc_conn_rcv_sub() returns
0 or -1 only, we don't need to check for "> 0".
Fixes: c5fa7b3cf3cb ("tipc: introduce new TIPC server infrastructure")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/tipc')
| -rw-r--r-- | net/tipc/topsrv.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/net/tipc/topsrv.c b/net/tipc/topsrv.c index b0f9aa521670..e3b427a70398 100644 --- a/net/tipc/topsrv.c +++ b/net/tipc/topsrv.c @@ -206,6 +206,7 @@ static struct tipc_conn *tipc_conn_alloc(struct tipc_topsrv *s, struct socket *s set_bit(CF_CONNECTED, &con->flags); con->server = s; con->sock = sock; + conn_get(con); spin_unlock_bh(&s->idr_lock); return con; @@ -484,6 +485,7 @@ static void tipc_topsrv_accept(struct work_struct *work) /* Wake up receive process in case of 'SYN+' message */ newsk->sk_data_ready(newsk); + conn_put(con); } } @@ -583,10 +585,11 @@ bool tipc_topsrv_kern_subscr(struct net *net, u32 port, u32 type, u32 lower, *conid = con->conid; rc = tipc_conn_rcv_sub(tipc_topsrv(net), con, &sub); - if (rc >= 0) - return true; + if (rc) + conn_put(con); + conn_put(con); - return false; + return !rc; } void tipc_topsrv_kern_unsubscr(struct net *net, int conid) |