UPSTREAM: ipv4: fix null-deref in ipv4_link_failure

[ Upstream commit 0113d9c9d1ccc07f5a3710dac4aa24b6d711278c ]

Currently, we assume the skb is associated with a device before calling
__ip_options_compile, which is not always the case if it is re-routed by
ipvs.
When skb->dev is NULL, dev_net(skb->dev) will become null-dereference.
This patch adds a check for the edge case and switch to use the net_device
from the rtable when skb->dev is NULL.

Bug: 304913674
Fixes: ed0de45a10 ("ipv4: recompile ip options in ipv4_link_failure")
Suggested-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Kyle Zeng <zengyhkyle@gmail.com>
Cc: Stephen Suryaputra <ssuryaextr@gmail.com>
Cc: Vadim Fedorenko <vfedorenko@novek.ru>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 2712545e535d7a2e4c53b9c9658a9c88c6055862)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: Ie840ff3351e487f7095c49fac4fdd1e81021a982
This commit is contained in:
Kyle Zeng 2023-09-14 22:12:57 -07:00 committed by Lee Jones
parent cd7744312f
commit f8424e6555

View File

@ -1240,6 +1240,7 @@ static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
static void ipv4_send_dest_unreach(struct sk_buff *skb) static void ipv4_send_dest_unreach(struct sk_buff *skb)
{ {
struct net_device *dev;
struct ip_options opt; struct ip_options opt;
int res; int res;
@ -1257,7 +1258,8 @@ static void ipv4_send_dest_unreach(struct sk_buff *skb)
opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr); opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
rcu_read_lock(); rcu_read_lock();
res = __ip_options_compile(dev_net(skb->dev), &opt, skb, NULL); dev = skb->dev ? skb->dev : skb_rtable(skb)->dst.dev;
res = __ip_options_compile(dev_net(dev), &opt, skb, NULL);
rcu_read_unlock(); rcu_read_unlock();
if (res) if (res)