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| author |   Eric Dumazet <edumazet@google.com> | 2025-02-12 14:10:21 +0000 |
|---|---|---|
| committer |   Jakub Kicinski <kuba@kernel.org> | 2025-02-13 08:37:21 -0800 |
| commit | a527750d877fd334de87eef81f1cb5f0f0ca3373 (patch) | |
| tree | 0f608fb0e2f6a8221831a1eeb06e5e176b44ab83 /net | |
| parent | team: better TEAM_OPTION_TYPE_STRING validation (diff) | |
| download | wireguard-linux-a527750d877fd334de87eef81f1cb5f0f0ca3373.tar.xz wireguard-linux-a527750d877fd334de87eef81f1cb5f0f0ca3373.zip | |
ipv6: mcast: add RCU protection to mld_newpack()
mld_newpack() can be called without RTNL or RCU being held.
Note that we no longer can use sock_alloc_send_skb() because
ipv6.igmp_sk uses GFP_KERNEL allocations which can sleep.
Instead use alloc_skb() and charge the net->ipv6.igmp_sk
socket under RCU protection.
Fixes: b8ad0cbc58f7 ("[NETNS][IPV6] mcast - handle several network namespace")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250212141021.1663666-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv6/mcast.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index 81a739ebf709..65831b4fee1f 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -1773,21 +1773,19 @@ static struct sk_buff *mld_newpack(struct inet6_dev *idev, unsigned int mtu) struct net_device *dev = idev->dev; int hlen = LL_RESERVED_SPACE(dev); int tlen = dev->needed_tailroom; - struct net *net = dev_net(dev); const struct in6_addr *saddr; struct in6_addr addr_buf; struct mld2_report *pmr; struct sk_buff *skb; unsigned int size; struct sock *sk; - int err; + struct net *net; - sk = net->ipv6.igmp_sk; /* we assume size > sizeof(ra) here * Also try to not allocate high-order pages for big MTU */ size = min_t(int, mtu, PAGE_SIZE / 2) + hlen + tlen; - skb = sock_alloc_send_skb(sk, size, 1, &err); + skb = alloc_skb(size, GFP_KERNEL); if (!skb) return NULL; @@ -1795,6 +1793,12 @@ static struct sk_buff *mld_newpack(struct inet6_dev *idev, unsigned int mtu) skb_reserve(skb, hlen); skb_tailroom_reserve(skb, mtu, tlen); + rcu_read_lock(); + + net = dev_net_rcu(dev); + sk = net->ipv6.igmp_sk; + skb_set_owner_w(skb, sk); + if (ipv6_get_lladdr(dev, &addr_buf, IFA_F_TENTATIVE)) { /* <draft-ietf-magma-mld-source-05.txt>: * use unspecified address as the source address @@ -1806,6 +1810,8 @@ static struct sk_buff *mld_newpack(struct inet6_dev *idev, unsigned int mtu) ip6_mc_hdr(sk, skb, dev, saddr, &mld2_all_mcr, NEXTHDR_HOP, 0); + rcu_read_unlock(); + skb_put_data(skb, ra, sizeof(ra)); skb_set_transport_header(skb, skb_tail_pointer(skb) - skb->data); |