| Message ID | 20210713054019.409273-1-mudongliangabcd@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | ieee802154: hwsim: fix memory leak in __pskb_copy_fclone | expand |
Hi, On Tue, 13 Jul 2021 at 01:40, Dongliang Mu <mudongliangabcd@gmail.com> wrote: > > hwsim_hw_xmit fails to deallocate the newskb copied by pskb_copy. Fix > this by adding kfree_skb after ieee802154_rx_irqsafe. > > [<ffffffff836433fb>] __alloc_skb+0x22b/0x250 net/core/skbuff.c:414 > [<ffffffff8364ad95>] __pskb_copy_fclone+0x75/0x360 net/core/skbuff.c:1609 > [<ffffffff82ae65e3>] __pskb_copy include/linux/skbuff.h:1176 [inline] > [<ffffffff82ae65e3>] pskb_copy include/linux/skbuff.h:3207 [inline] > [<ffffffff82ae65e3>] hwsim_hw_xmit+0xd3/0x140 drivers/net/ieee802154/mac802154_hwsim.c:132 > [<ffffffff83ff8f47>] drv_xmit_async net/mac802154/driver-ops.h:16 [inline] > [<ffffffff83ff8f47>] ieee802154_tx+0xc7/0x190 net/mac802154/tx.c:83 > [<ffffffff83ff9138>] ieee802154_subif_start_xmit+0x58/0x70 net/mac802154/tx.c:132 > [<ffffffff83670b82>] __netdev_start_xmit include/linux/netdevice.h:4944 [inline] > [<ffffffff83670b82>] netdev_start_xmit include/linux/netdevice.h:4958 [inline] > [<ffffffff83670b82>] xmit_one net/core/dev.c:3658 [inline] > [<ffffffff83670b82>] dev_hard_start_xmit+0xe2/0x330 net/core/dev.c:3674 > [<ffffffff83718028>] sch_direct_xmit+0xf8/0x520 net/sched/sch_generic.c:342 > [<ffffffff8367193b>] __dev_xmit_skb net/core/dev.c:3874 [inline] > [<ffffffff8367193b>] __dev_queue_xmit+0xa3b/0x1360 net/core/dev.c:4241 > [<ffffffff83ff5437>] dgram_sendmsg+0x437/0x570 net/ieee802154/socket.c:682 > [<ffffffff836345b6>] sock_sendmsg_nosec net/socket.c:702 [inline] > [<ffffffff836345b6>] sock_sendmsg+0x56/0x80 net/socket.c:722 > > Fixes: f25da51fdc38 ("ieee802154: hwsim: add replacement for fakelb") > Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com> sorry, I don't get the fix. Is this a memory leak? I remember there was something reported by syzkaller [0] but I wasn't able yet to get into it. Is it what you referring to? __pskb_copy_fclone() shows "The returned buffer has a reference count of 1" and ieee802154_rx_irqsafe() will queue the skb for a tasklet. With your patch it will be immediately freed and a use after free will occur. I believe there is something wrong in the error path of 802.15.4 frame parsing and that's why we sometimes have a leaks there. I need to test this patch, but I don't get how this patch is supposed to fix the issue. - Alex [0] https://groups.google.com/g/syzkaller-bugs/c/EoIvZbk3Zfo/m/AlKUiErlAwAJ
diff --git a/drivers/net/ieee802154/mac802154_hwsim.c b/drivers/net/ieee802154/mac802154_hwsim.c index ebc976b7fcc2..d97ed033ac77 100644 --- a/drivers/net/ieee802154/mac802154_hwsim.c +++ b/drivers/net/ieee802154/mac802154_hwsim.c @@ -132,9 +132,11 @@ static int hwsim_hw_xmit(struct ieee802154_hw *hw, struct sk_buff *skb) struct sk_buff *newskb = pskb_copy(skb, GFP_ATOMIC); einfo = rcu_dereference(e->info); - if (newskb) + if (newskb) { ieee802154_rx_irqsafe(e->endpoint->hw, newskb, einfo->lqi); + kfree_skb(newskb); + } } } rcu_read_unlock();
hwsim_hw_xmit fails to deallocate the newskb copied by pskb_copy. Fix this by adding kfree_skb after ieee802154_rx_irqsafe. [<ffffffff836433fb>] __alloc_skb+0x22b/0x250 net/core/skbuff.c:414 [<ffffffff8364ad95>] __pskb_copy_fclone+0x75/0x360 net/core/skbuff.c:1609 [<ffffffff82ae65e3>] __pskb_copy include/linux/skbuff.h:1176 [inline] [<ffffffff82ae65e3>] pskb_copy include/linux/skbuff.h:3207 [inline] [<ffffffff82ae65e3>] hwsim_hw_xmit+0xd3/0x140 drivers/net/ieee802154/mac802154_hwsim.c:132 [<ffffffff83ff8f47>] drv_xmit_async net/mac802154/driver-ops.h:16 [inline] [<ffffffff83ff8f47>] ieee802154_tx+0xc7/0x190 net/mac802154/tx.c:83 [<ffffffff83ff9138>] ieee802154_subif_start_xmit+0x58/0x70 net/mac802154/tx.c:132 [<ffffffff83670b82>] __netdev_start_xmit include/linux/netdevice.h:4944 [inline] [<ffffffff83670b82>] netdev_start_xmit include/linux/netdevice.h:4958 [inline] [<ffffffff83670b82>] xmit_one net/core/dev.c:3658 [inline] [<ffffffff83670b82>] dev_hard_start_xmit+0xe2/0x330 net/core/dev.c:3674 [<ffffffff83718028>] sch_direct_xmit+0xf8/0x520 net/sched/sch_generic.c:342 [<ffffffff8367193b>] __dev_xmit_skb net/core/dev.c:3874 [inline] [<ffffffff8367193b>] __dev_queue_xmit+0xa3b/0x1360 net/core/dev.c:4241 [<ffffffff83ff5437>] dgram_sendmsg+0x437/0x570 net/ieee802154/socket.c:682 [<ffffffff836345b6>] sock_sendmsg_nosec net/socket.c:702 [inline] [<ffffffff836345b6>] sock_sendmsg+0x56/0x80 net/socket.c:722 Fixes: f25da51fdc38 ("ieee802154: hwsim: add replacement for fakelb") Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com> --- drivers/net/ieee802154/mac802154_hwsim.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)