From: Soenke Huster soenke.huster@eknoes.de
[ Upstream commit 8c0427842aaef161a38ac83b7e8d8fe050b4be04 ]
An invalid packet with a length shorter than the specified length in the netlink header can lead to use-after-frees and slab-out-of-bounds in the processing of the netlink attributes, such as the following:
BUG: KASAN: slab-out-of-bounds in __nla_validate_parse+0x1258/0x2010 Read of size 2 at addr ffff88800ac7952c by task kworker/0:1/12
Workqueue: events hwsim_virtio_rx_work Call Trace: <TASK> dump_stack_lvl+0x45/0x5d print_report.cold+0x5e/0x5e5 kasan_report+0xb1/0x1c0 __nla_validate_parse+0x1258/0x2010 __nla_parse+0x22/0x30 hwsim_virtio_handle_cmd.isra.0+0x13f/0x2d0 hwsim_virtio_rx_work+0x1b2/0x370 process_one_work+0x8df/0x1530 worker_thread+0x575/0x11a0 kthread+0x29d/0x340 ret_from_fork+0x22/0x30 </TASK>
Discarding packets with an invalid length solves this. Therefore, skb->len must be set at reception.
Change-Id: Ieaeb9a4c62d3beede274881a7c2722c6c6f477b6 Signed-off-by: Soenke Huster soenke.huster@eknoes.de Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/mac80211_hwsim.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c index 8e412125a49c..50190ded7edc 100644 --- a/drivers/net/wireless/mac80211_hwsim.c +++ b/drivers/net/wireless/mac80211_hwsim.c @@ -4209,6 +4209,10 @@ static int hwsim_virtio_handle_cmd(struct sk_buff *skb)
nlh = nlmsg_hdr(skb); gnlh = nlmsg_data(nlh); + + if (skb->len < nlh->nlmsg_len) + return -EINVAL; + err = genlmsg_parse(nlh, &hwsim_genl_family, tb, HWSIM_ATTR_MAX, hwsim_genl_policy, NULL); if (err) { @@ -4251,7 +4255,8 @@ static void hwsim_virtio_rx_work(struct work_struct *work) spin_unlock_irqrestore(&hwsim_virtio_lock, flags);
skb->data = skb->head; - skb_set_tail_pointer(skb, len); + skb_reset_tail_pointer(skb); + skb_put(skb, len); hwsim_virtio_handle_cmd(skb);
spin_lock_irqsave(&hwsim_virtio_lock, flags);