5.4-stable review patch. If anyone has any objections, please let me know.
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From: Kuniyuki Iwashima kuniyu@google.com
[ Upstream commit 62dba28275a9a3104d4e33595c7b3328d4032d8d ]
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 kuniyu@google.com Reviewed-by: Simon Horman horms@kernel.org Link: https://patch.msgid.link/20250704062416.1613927-3-kuniyu@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/atm/clip.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/net/atm/clip.c b/net/atm/clip.c index d5363ae5296ad..8415ac2805474 100644 --- a/net/atm/clip.c +++ b/net/atm/clip.c @@ -646,6 +646,9 @@ 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); @@ -670,6 +673,7 @@ 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) { @@ -690,14 +694,18 @@ 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);