From 93a2014afbace907178afc3c9c1e62c9a338595a Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Fri, 1 May 2020 11:11:08 -0700 Subject: atm: fix a UAF in lec_arp_clear_vccs() Gengming reported a UAF in lec_arp_clear_vccs(), where we add a vcc socket to an entry in a per-device list but free the socket without removing it from the list when vcc->dev is NULL. We need to call lec_vcc_close() to search and remove those entries contain the vcc being destroyed. This can be done by calling vcc->push(vcc, NULL) unconditionally in vcc_destroy_socket(). Another issue discovered by Gengming's reproducer is the vcc->dev may point to the static device lecatm_dev, for which we don't need to register/unregister device, so we can just check for vcc->dev->ops->owner. Reported-by: Gengming Liu Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- net/atm/common.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) (limited to 'net/atm') diff --git a/net/atm/common.c b/net/atm/common.c index 0ce530af534d..8575f5d52087 100644 --- a/net/atm/common.c +++ b/net/atm/common.c @@ -177,18 +177,18 @@ static void vcc_destroy_socket(struct sock *sk) set_bit(ATM_VF_CLOSE, &vcc->flags); clear_bit(ATM_VF_READY, &vcc->flags); - if (vcc->dev) { - if (vcc->dev->ops->close) - vcc->dev->ops->close(vcc); - if (vcc->push) - vcc->push(vcc, NULL); /* atmarpd has no push */ - module_put(vcc->owner); - - while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) { - atm_return(vcc, skb->truesize); - kfree_skb(skb); - } + if (vcc->dev && vcc->dev->ops->close) + vcc->dev->ops->close(vcc); + if (vcc->push) + vcc->push(vcc, NULL); /* atmarpd has no push */ + module_put(vcc->owner); + + while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) { + atm_return(vcc, skb->truesize); + kfree_skb(skb); + } + if (vcc->dev && vcc->dev->ops->owner) { module_put(vcc->dev->ops->owner); atm_dev_put(vcc->dev); } -- cgit From 8d9f73c0ad2f20e9fed5380de0a3097825859d03 Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Fri, 1 May 2020 11:11:09 -0700 Subject: atm: fix a memory leak of vcc->user_back In lec_arp_clear_vccs() only entry->vcc is freed, but vcc could be installed on entry->recv_vcc too in lec_vcc_added(). This fixes the following memory leak: unreferenced object 0xffff8880d9266b90 (size 16): comm "atm2", pid 425, jiffies 4294907980 (age 23.488s) hex dump (first 16 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 6b 6b 6b a5 ............kkk. backtrace: [<(____ptrval____)>] kmem_cache_alloc_trace+0x10e/0x151 [<(____ptrval____)>] lane_ioctl+0x4b3/0x569 [<(____ptrval____)>] do_vcc_ioctl+0x1ea/0x236 [<(____ptrval____)>] svc_ioctl+0x17d/0x198 [<(____ptrval____)>] sock_do_ioctl+0x47/0x12f [<(____ptrval____)>] sock_ioctl+0x2f9/0x322 [<(____ptrval____)>] vfs_ioctl+0x1e/0x2b [<(____ptrval____)>] ksys_ioctl+0x61/0x80 [<(____ptrval____)>] __x64_sys_ioctl+0x16/0x19 [<(____ptrval____)>] do_syscall_64+0x57/0x65 [<(____ptrval____)>] entry_SYSCALL_64_after_hwframe+0x49/0xb3 Cc: Gengming Liu Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- net/atm/lec.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'net/atm') diff --git a/net/atm/lec.c b/net/atm/lec.c index 25fa3a7b72bd..ca37f5a71f5e 100644 --- a/net/atm/lec.c +++ b/net/atm/lec.c @@ -1264,6 +1264,12 @@ static void lec_arp_clear_vccs(struct lec_arp_table *entry) entry->vcc = NULL; } if (entry->recv_vcc) { + struct atm_vcc *vcc = entry->recv_vcc; + struct lec_vcc_priv *vpriv = LEC_VCC_PRIV(vcc); + + kfree(vpriv); + vcc->user_back = NULL; + entry->recv_vcc->push = entry->old_recv_push; vcc_release_async(entry->recv_vcc, -EPIPE); entry->recv_vcc = NULL; -- cgit