From 62dba28275a9a3104d4e33595c7b3328d4032d8d Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Fri, 4 Jul 2025 06:23:52 +0000 Subject: [PATCH] atm: clip: Fix memory leak of struct clip_vcc. ioctl(ATMARP_MKIP) allocates struct clip_vcc and set it to vcc->user_back. The code assumes that vcc_destroy_socket() passes NULL skb to vcc->push() when the socket is close()d, and then clip_push() frees clip_vcc. However, ioctl(ATMARPD_CTRL) sets NULL to vcc->push() in atm_init_atmarp(), resulting in memory leak. Let's serialise two ioctl() by lock_sock() and check vcc->push() in atm_init_atmarp() to prevent memleak. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima Reviewed-by: Simon Horman Link: https://patch.msgid.link/20250704062416.1613927-3-kuniyu@google.com Signed-off-by: Jakub Kicinski --- net/atm/clip.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/atm/clip.c b/net/atm/clip.c index f36f2c7d8714..9c9c6c3d9886 100644 --- a/net/atm/clip.c +++ b/net/atm/clip.c @@ -645,6 +645,9 @@ static struct atm_dev atmarpd_dev = { static int atm_init_atmarp(struct atm_vcc *vcc) { + if (vcc->push == clip_push) + return -EINVAL; + mutex_lock(&atmarpd_lock); if (atmarpd) { mutex_unlock(&atmarpd_lock); @@ -669,6 +672,7 @@ static int atm_init_atmarp(struct atm_vcc *vcc) static int clip_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) { struct atm_vcc *vcc = ATM_SD(sock); + struct sock *sk = sock->sk; int err = 0; switch (cmd) { @@ -689,14 +693,18 @@ static int clip_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) err = clip_create(arg); break; case ATMARPD_CTRL: + lock_sock(sk); err = atm_init_atmarp(vcc); if (!err) { sock->state = SS_CONNECTED; __module_get(THIS_MODULE); } + release_sock(sk); break; case ATMARP_MKIP: + lock_sock(sk); err = clip_mkip(vcc, arg); + release_sock(sk); break; case ATMARP_SETENTRY: err = clip_setentry(vcc, (__force __be32)arg); -- 2.25.1