kernel/linux.git/net/ipv4/arp.c, branch v6.18.22

arp: do not assume dev_hard_header() does not change skb->head

2026-01-17T15:35:30+00:00

[ Upstream commit c92510f5e3f82ba11c95991824a41e59a9c5ed81 ] arp_create() is the only dev_hard_header() caller making assumption about skb->head being unchanged. A recent commit broke this assumption. Initialize @arp pointer after dev_hard_header() call. Fixes: db5b4e39c4e6 ("ip6_gre: make ip6gre_header() robust") Reported-by: syzbot+58b44a770a1585795351@syzkaller.appspotmail.com Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260107212250.384552-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: set net.core.rmem_max and net.core.wmem_max to 4 MB

2025-08-21T02:35:00+00:00

SO_RCVBUF and SO_SNDBUF have limited range today, unless distros or system admins change rmem_max and wmem_max. Even iproute2 uses 1 MB SO_RCVBUF which is capped by the kernel. Decouple [rw]mem_max and [rw]mem_default and increase [rw]mem_max to 4 MB. Before: $ sysctl net.core.rmem_default net.core.rmem_max net.core.wmem_default net.core.wmem_max net.core.rmem_default = 212992 net.core.rmem_max = 212992 net.core.wmem_default = 212992 net.core.wmem_max = 212992 After: $ sysctl net.core.rmem_default net.core.rmem_max net.core.wmem_default net.core.wmem_max net.core.rmem_default = 212992 net.core.rmem_max = 4194304 net.core.wmem_default = 212992 net.core.wmem_max = 4194304 Signed-off-by: Eric Dumazet Reviewed-by: Neal Cardwell Link: https://patch.msgid.link/20250819174030.1986278-1-edumazet@google.com Signed-off-by: Jakub Kicinski

neighbour: Update pneigh_entry in pneigh_create().

2025-07-17T23:25:22+00:00

neigh_add() updates pneigh_entry() found or created by pneigh_create(). This update is serialised by RTNL, but we will remove it. Let's move the update part to pneigh_create() and make it return errno instead of a pointer of pneigh_entry. Now, the pneigh code is RTNL free. Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250716221221.442239-16-kuniyu@google.com Signed-off-by: Jakub Kicinski

neighbour: Split pneigh_lookup().

2025-07-17T23:25:20+00:00

pneigh_lookup() has ASSERT_RTNL() in the middle of the function, which is confusing. When called with the last argument, creat, 0, pneigh_lookup() literally looks up a proxy neighbour entry. This is the case of the reader path as the fast path and RTM_GETNEIGH. pneigh_lookup(), however, creates a pneigh_entry when called with creat 1 from RTM_NEWNEIGH and SIOCSARP, which require RTNL. Let's split pneigh_lookup() into two functions. We will convert all the reader paths to RCU, and read_lock_bh(&tbl->lock) in the new pneigh_lookup() will be dropped. Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250716221221.442239-6-kuniyu@google.com Signed-off-by: Jakub Kicinski

net: arp: use kfree_skb_reason() in arp_rcv()

2025-06-14T00:30:02+00:00

Replace kfree_skb() with kfree_skb_reason() in arp_rcv(). Signed-off-by: Qiu Yutan Signed-off-by: Jiang Kun Link: https://patch.msgid.link/20250612110259698Q2KNNOPQhnIApRskKN3Hi@zte.com.cn Signed-off-by: Jakub Kicinski

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2025-02-20T18:37:30+00:00

Cross-merge networking fixes after downstream PR (net-6.14-rc4). No conflicts or adjacent changes. Signed-off-by: Jakub Kicinski

arp: switch to dev_getbyhwaddr() in arp_req_set_public()

2025-02-20T03:00:01+00:00

The arp_req_set_public() function is called with the rtnl lock held, which provides enough synchronization protection. This makes the RCU variant of dev_getbyhwaddr() unnecessary. Switch to using the simpler dev_getbyhwaddr() function since we already have the required rtnl locking. This change helps maintain consistency in the networking code by using the appropriate helper function for the existing locking context. Since we're not holding the RCU read lock in arp_req_set_public() existing code could trigger false positive locking warnings. Fixes: 941666c2e3e0 ("net: RCU conversion of dev_getbyhwaddr() and arp_ioctl()") Suggested-by: Kuniyuki Iwashima Reviewed-by: Kuniyuki Iwashima Signed-off-by: Breno Leitao Link: https://patch.msgid.link/20250218-arm_fix_selftest-v5-2-d3d6892db9e1@debian.org Signed-off-by: Jakub Kicinski

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2025-02-13T20:43:30+00:00

Cross-merge networking fixes after downstream PR (net-6.14-rc3). No conflicts or adjacent changes. Signed-off-by: Jakub Kicinski

arp: Convert SIOCDARP and SIOCSARP to per-netns RTNL.

2025-02-13T10:33:44+00:00

ioctl(SIOCDARP/SIOCSARP) operates on a single netns fetched from an AF_INET socket in inet_ioctl(). Let's hold rtnl_net_lock() for SIOCDARP and SIOCSARP. Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20250211045057.10419-1-kuniyu@amazon.com Signed-off-by: Paolo Abeni

arp: use RCU protection in arp_xmit()

2025-02-11T02:09:09+00:00

arp_xmit() can be called without RTNL or RCU protection. Use RCU protection to avoid potential UAF. Fixes: 29a26a568038 ("netfilter: Pass struct net into the netfilter hooks") Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250207135841.1948589-5-edumazet@google.com Signed-off-by: Jakub Kicinski