From: Kyle Zeng zengyhkyle@gmail.com

mainline inclusion from mainline-v6.6-rc3 commit 0113d9c9d1ccc07f5a3710dac4aa24b6d711278c category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I85DZB CVE: CVE-2023-42754

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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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.

Fixes: ed0de45a1008 ("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: Lu Wei luwei32@huawei.com --- net/ipv4/route.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 216f76b548ff..f85eaf566b9b 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -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) { + struct net_device *dev; struct ip_options opt; 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);

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();

if (res)