linux.git/include/net/ip.h, branch v6.13-rc4 Linux kernel source tree ipv4: Switch inet_addr_hash() to less predictable hash. 2024-10-23T11:17:35+00:00 Kuniyuki Iwashima kuniyu@amazon.com 2024-10-18T01:41:00+00:00 c972c1c41d9b20fb38b54e77dcee763e27e715a9 Recently, commit 4a0ec2aa0704 ("ipv6: switch inet6_addr_hash() to less predictable hash") and commit 4daf4dc275f1 ("ipv6: switch inet6_acaddr_hash() to less predictable hash") hardened IPv6 address hash functions. inet_addr_hash() is also highly predictable, and a malicious use could abuse a specific bucket. Let's follow the change on IPv4 by using jhash_1word(). Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20241018014100.93776-1-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> 
Recently, commit 4a0ec2aa0704 ("ipv6: switch inet6_addr_hash()
to less predictable hash") and commit 4daf4dc275f1 ("ipv6: switch
inet6_acaddr_hash() to less predictable hash") hardened IPv6
address hash functions.

inet_addr_hash() is also highly predictable, and a malicious use
could abuse a specific bucket.

Let's follow the change on IPv4 by using jhash_1word().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241018014100.93776-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
ipv4: tcp: give socket pointer to control skbs 2024-10-15T00:39:37+00:00 Eric Dumazet edumazet@google.com 2024-10-10T17:48:17+00:00 79636038d37e7bd4d078238f2a3f002cab4423bc ip_send_unicast_reply() send orphaned 'control packets'. These are RST packets and also ACK packets sent from TIME_WAIT. Some eBPF programs would prefer to have a meaningful skb->sk pointer as much as possible. This means that TCP can now attach TIME_WAIT sockets to outgoing skbs. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Brian Vazquez <brianvv@google.com> Link: https://patch.msgid.link/20241010174817.1543642-6-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
ip_send_unicast_reply() send orphaned 'control packets'.

These are RST packets and also ACK packets sent from TIME_WAIT.

Some eBPF programs would prefer to have a meaningful skb->sk
pointer as much as possible.

This means that TCP can now attach TIME_WAIT sockets to outgoing
skbs.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Brian Vazquez <brianvv@google.com>
Link: https://patch.msgid.link/20241010174817.1543642-6-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ipv4: Convert ip_route_input() to dscp_t. 2024-10-03T23:21:21+00:00 Guillaume Nault gnault@redhat.com 2024-10-01T19:28:43+00:00 7e863e5db6185b1add0df4cb01b31a4ed1c4b738 Pass a dscp_t variable to ip_route_input(), instead of a plain u8, to prevent accidental setting of ECN bits in ->flowi4_tos. Callers of ip_route_input() to consider are: * input_action_end_dx4_finish() and input_action_end_dt4() in net/ipv6/seg6_local.c. These functions set the tos parameter to 0, which is already a valid dscp_t value, so they don't need to be adjusted for the new prototype. * icmp_route_lookup(), which already has a dscp_t variable to pass as parameter. We just need to remove the inet_dscp_to_dsfield() conversion. * br_nf_pre_routing_finish(), ip_options_rcv_srr() and ip4ip6_err(), which get the DSCP directly from IPv4 headers. Define a helper to read the .tos field of struct iphdr as dscp_t, so that these function don't have to do the conversion manually. While there, declare *iph as const in br_nf_pre_routing_finish(), declare its local variables in reverse-christmas-tree order and move the "err = ip_route_input()" assignment out of the conditional to avoid checkpatch warning. Signed-off-by: Guillaume Nault <gnault@redhat.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/e9d40781d64d3d69f4c79ac8a008b8d67a033e8d.1727807926.git.gnault@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Pass a dscp_t variable to ip_route_input(), instead of a plain u8, to
prevent accidental setting of ECN bits in ->flowi4_tos.

Callers of ip_route_input() to consider are:

  * input_action_end_dx4_finish() and input_action_end_dt4() in
    net/ipv6/seg6_local.c. These functions set the tos parameter to 0,
    which is already a valid dscp_t value, so they don't need to be
    adjusted for the new prototype.

  * icmp_route_lookup(), which already has a dscp_t variable to pass as
    parameter. We just need to remove the inet_dscp_to_dsfield()
    conversion.

  * br_nf_pre_routing_finish(), ip_options_rcv_srr() and ip4ip6_err(),
    which get the DSCP directly from IPv4 headers. Define a helper to
    read the .tos field of struct iphdr as dscp_t, so that these
    function don't have to do the conversion manually.

While there, declare *iph as const in br_nf_pre_routing_finish(),
declare its local variables in reverse-christmas-tree order and move
the "err = ip_route_input()" assignment out of the conditional to avoid
checkpatch warning.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/e9d40781d64d3d69f4c79ac8a008b8d67a033e8d.1727807926.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ipv4: Unmask upper DSCP bits in get_rttos() 2024-08-31T16:44:51+00:00 Ido Schimmel idosch@nvidia.com 2024-08-29T06:54:52+00:00 356d054a4967e6190ee558b8e839fad3e9db35ec The function is used by a few socket types to retrieve the TOS value with which to perform the FIB lookup for packets sent through the socket (flowi4_tos). If a DS field was passed using the IP_TOS control message, then it is used. Otherwise the one specified via the IP_TOS socket option. Unmask the upper DSCP bits so that in the future the lookup could be performed according to the full DSCP value. Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
The function is used by a few socket types to retrieve the TOS value
with which to perform the FIB lookup for packets sent through the socket
(flowi4_tos). If a DS field was passed using the IP_TOS control message,
then it is used. Otherwise the one specified via the IP_TOS socket
option.

Unmask the upper DSCP bits so that in the future the lookup could be
performed according to the full DSCP value.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
icmp: icmp_msgs_per_sec and icmp_msgs_burst sysctls become per netns 2024-08-30T18:14:06+00:00 Eric Dumazet edumazet@google.com 2024-08-29T14:46:41+00:00 f17bf505ff89595df5147755e51441632a5dc563 Previous patch made ICMP rate limits per netns, it makes sense to allow each netns to change the associated sysctl. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20240829144641.3880376-4-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Previous patch made ICMP rate limits per netns, it makes sense
to allow each netns to change the associated sysctl.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20240829144641.3880376-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
icmp: move icmp_global.credit and icmp_global.stamp to per netns storage 2024-08-30T18:14:06+00:00 Eric Dumazet edumazet@google.com 2024-08-29T14:46:40+00:00 b056b4cd9178f7a1d5d57f7b48b073c29729ddaa Host wide ICMP ratelimiter should be per netns, to provide better isolation. Following patch in this series makes the sysctl per netns. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20240829144641.3880376-3-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Host wide ICMP ratelimiter should be per netns, to provide better isolation.

Following patch in this series makes the sysctl per netns.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20240829144641.3880376-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
icmp: change the order of rate limits 2024-08-30T18:14:06+00:00 Eric Dumazet edumazet@google.com 2024-08-29T14:46:39+00:00 8c2bd38b95f75f3d2a08c93e35303e26d480d24e ICMP messages are ratelimited : After the blamed commits, the two rate limiters are applied in this order: 1) host wide ratelimit (icmp_global_allow()) 2) Per destination ratelimit (inetpeer based) In order to avoid side-channels attacks, we need to apply the per destination check first. This patch makes the following change : 1) icmp_global_allow() checks if the host wide limit is reached. But credits are not yet consumed. This is deferred to 3) 2) The per destination limit is checked/updated. This might add a new node in inetpeer tree. 3) icmp_global_consume() consumes tokens if prior operations succeeded. This means that host wide ratelimit is still effective in keeping inetpeer tree small even under DDOS. As a bonus, I removed icmp_global.lock as the fast path can use a lock-free operation. Fixes: c0303efeab73 ("net: reduce cycles spend on ICMP replies that gets rate limited") Fixes: 4cdf507d5452 ("icmp: add a global rate limitation") Reported-by: Keyu Man <keyu.man@email.ucr.edu> Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Cc: Jesper Dangaard Brouer <hawk@kernel.org> Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20240829144641.3880376-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
ICMP messages are ratelimited :

After the blamed commits, the two rate limiters are applied in this order:

1) host wide ratelimit (icmp_global_allow())

2) Per destination ratelimit (inetpeer based)

In order to avoid side-channels attacks, we need to apply
the per destination check first.

This patch makes the following change :

1) icmp_global_allow() checks if the host wide limit is reached.
   But credits are not yet consumed. This is deferred to 3)

2) The per destination limit is checked/updated.
   This might add a new node in inetpeer tree.

3) icmp_global_consume() consumes tokens if prior operations succeeded.

This means that host wide ratelimit is still effective
in keeping inetpeer tree small even under DDOS.

As a bonus, I removed icmp_global.lock as the fast path
can use a lock-free operation.

Fixes: c0303efeab73 ("net: reduce cycles spend on ICMP replies that gets rate limited")
Fixes: 4cdf507d5452 ("icmp: add a global rate limitation")
Reported-by: Keyu Man <keyu.man@email.ucr.edu>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Cc: Jesper Dangaard Brouer <hawk@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20240829144641.3880376-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: remove NULL-pointer net parameter in ip_metrics_convert 2024-06-05T09:06:00+00:00 Jason Xing kernelxing@tencent.com 2024-05-31T15:46:34+00:00 61e2bbafb00e4b9a5de45e6448a7b6b818658576 When I was doing some experiments, I found that when using the first parameter, namely, struct net, in ip_metrics_convert() always triggers NULL pointer crash. Then I digged into this part, realizing that we can remove this one due to its uselessness. Signed-off-by: Jason Xing <kernelxing@tencent.com> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> 
When I was doing some experiments, I found that when using the first
parameter, namely, struct net, in ip_metrics_convert() always triggers NULL
pointer crash. Then I digged into this part, realizing that we can remove
this one due to its uselessness.

Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
inet: introduce dst_rtable() helper 2024-05-01T01:32:38+00:00 Eric Dumazet edumazet@google.com 2024-04-29T13:30:09+00:00 05d6d492097c55f2d153fc3fd33cbe78e1e28e0a I added dst_rt6_info() in commit e8dfd42c17fa ("ipv6: introduce dst_rt6_info() helper") This patch does a similar change for IPv4. Instead of (struct rtable *)dst casts, we can use : #define dst_rtable(_ptr) \ container_of_const(_ptr, struct rtable, dst) Patch is smaller than IPv6 one, because IPv4 has skb_rtable() helper. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Link: https://lore.kernel.org/r/20240429133009.1227754-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
I added dst_rt6_info() in commit
e8dfd42c17fa ("ipv6: introduce dst_rt6_info() helper")

This patch does a similar change for IPv4.

Instead of (struct rtable *)dst casts, we can use :

 #define dst_rtable(_ptr) \
             container_of_const(_ptr, struct rtable, dst)

Patch is smaller than IPv6 one, because IPv4 has skb_rtable() helper.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Link: https://lore.kernel.org/r/20240429133009.1227754-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ipmr: fix kernel panic when forwarding mcast packets 2024-01-27T05:05:26+00:00 Nicolas Dichtel nicolas.dichtel@6wind.com 2024-01-25T14:18:47+00:00 e622502c310f1069fd9f41cd38210553115f610a The stacktrace was: [ 86.305548] BUG: kernel NULL pointer dereference, address: 0000000000000092 [ 86.306815] #PF: supervisor read access in kernel mode [ 86.307717] #PF: error_code(0x0000) - not-present page [ 86.308624] PGD 0 P4D 0 [ 86.309091] Oops: 0000 [#1] PREEMPT SMP NOPTI [ 86.309883] CPU: 2 PID: 3139 Comm: pimd Tainted: G U 6.8.0-6wind-knet #1 [ 86.311027] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.1-0-g0551a4be2c-prebuilt.qemu-project.org 04/01/2014 [ 86.312728] RIP: 0010:ip_mr_forward (/build/work/knet/net/ipv4/ipmr.c:1985) [ 86.313399] Code: f9 1f 0f 87 85 03 00 00 48 8d 04 5b 48 8d 04 83 49 8d 44 c5 00 48 8b 40 70 48 39 c2 0f 84 d9 00 00 00 49 8b 46 58 48 83 e0 fe <80> b8 92 00 00 00 00 0f 84 55 ff ff ff 49 83 47 38 01 45 85 e4 0f [ 86.316565] RSP: 0018:ffffad21c0583ae0 EFLAGS: 00010246 [ 86.317497] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 86.318596] RDX: ffff9559cb46c000 RSI: 0000000000000000 RDI: 0000000000000000 [ 86.319627] RBP: ffffad21c0583b30 R08: 0000000000000000 R09: 0000000000000000 [ 86.320650] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 86.321672] R13: ffff9559c093a000 R14: ffff9559cc00b800 R15: ffff9559c09c1d80 [ 86.322873] FS: 00007f85db661980(0000) GS:ffff955a79d00000(0000) knlGS:0000000000000000 [ 86.324291] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 86.325314] CR2: 0000000000000092 CR3: 000000002f13a000 CR4: 0000000000350ef0 [ 86.326589] Call Trace: [ 86.327036] <TASK> [ 86.327434] ? show_regs (/build/work/knet/arch/x86/kernel/dumpstack.c:479) [ 86.328049] ? __die (/build/work/knet/arch/x86/kernel/dumpstack.c:421 /build/work/knet/arch/x86/kernel/dumpstack.c:434) [ 86.328508] ? page_fault_oops (/build/work/knet/arch/x86/mm/fault.c:707) [ 86.329107] ? do_user_addr_fault (/build/work/knet/arch/x86/mm/fault.c:1264) [ 86.329756] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223) [ 86.330350] ? __irq_work_queue_local (/build/work/knet/kernel/irq_work.c:111 (discriminator 1)) [ 86.331013] ? exc_page_fault (/build/work/knet/./arch/x86/include/asm/paravirt.h:693 /build/work/knet/arch/x86/mm/fault.c:1515 /build/work/knet/arch/x86/mm/fault.c:1563) [ 86.331702] ? asm_exc_page_fault (/build/work/knet/./arch/x86/include/asm/idtentry.h:570) [ 86.332468] ? ip_mr_forward (/build/work/knet/net/ipv4/ipmr.c:1985) [ 86.333183] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223) [ 86.333920] ipmr_mfc_add (/build/work/knet/./include/linux/rcupdate.h:782 /build/work/knet/net/ipv4/ipmr.c:1009 /build/work/knet/net/ipv4/ipmr.c:1273) [ 86.334583] ? __pfx_ipmr_hash_cmp (/build/work/knet/net/ipv4/ipmr.c:363) [ 86.335357] ip_mroute_setsockopt (/build/work/knet/net/ipv4/ipmr.c:1470) [ 86.336135] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223) [ 86.336854] ? ip_mroute_setsockopt (/build/work/knet/net/ipv4/ipmr.c:1470) [ 86.337679] do_ip_setsockopt (/build/work/knet/net/ipv4/ip_sockglue.c:944) [ 86.338408] ? __pfx_unix_stream_read_actor (/build/work/knet/net/unix/af_unix.c:2862) [ 86.339232] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223) [ 86.339809] ? aa_sk_perm (/build/work/knet/security/apparmor/include/cred.h:153 /build/work/knet/security/apparmor/net.c:181) [ 86.340342] ip_setsockopt (/build/work/knet/net/ipv4/ip_sockglue.c:1415) [ 86.340859] raw_setsockopt (/build/work/knet/net/ipv4/raw.c:836) [ 86.341408] ? security_socket_setsockopt (/build/work/knet/security/security.c:4561 (discriminator 13)) [ 86.342116] sock_common_setsockopt (/build/work/knet/net/core/sock.c:3716) [ 86.342747] do_sock_setsockopt (/build/work/knet/net/socket.c:2313) [ 86.343363] __sys_setsockopt (/build/work/knet/./include/linux/file.h:32 /build/work/knet/net/socket.c:2336) [ 86.344020] __x64_sys_setsockopt (/build/work/knet/net/socket.c:2340) [ 86.344766] do_syscall_64 (/build/work/knet/arch/x86/entry/common.c:52 /build/work/knet/arch/x86/entry/common.c:83) [ 86.345433] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223) [ 86.346161] ? syscall_exit_work (/build/work/knet/./include/linux/audit.h:357 /build/work/knet/kernel/entry/common.c:160) [ 86.346938] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223) [ 86.347657] ? syscall_exit_to_user_mode (/build/work/knet/kernel/entry/common.c:215) [ 86.348538] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223) [ 86.349262] ? do_syscall_64 (/build/work/knet/./arch/x86/include/asm/cpufeature.h:171 /build/work/knet/arch/x86/entry/common.c:98) [ 86.349971] entry_SYSCALL_64_after_hwframe (/build/work/knet/arch/x86/entry/entry_64.S:129) The original packet in ipmr_cache_report() may be queued and then forwarded with ip_mr_forward(). This last function has the assumption that the skb dst is set. After the below commit, the skb dst is dropped by ipv4_pktinfo_prepare(), which causes the oops. Fixes: bb7403655b3c ("ipmr: support IP_PKTINFO on cache report IGMP msg") Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20240125141847.1931933-1-nicolas.dichtel@6wind.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
The stacktrace was:
[   86.305548] BUG: kernel NULL pointer dereference, address: 0000000000000092
[   86.306815] #PF: supervisor read access in kernel mode
[   86.307717] #PF: error_code(0x0000) - not-present page
[   86.308624] PGD 0 P4D 0
[   86.309091] Oops: 0000 [#1] PREEMPT SMP NOPTI
[   86.309883] CPU: 2 PID: 3139 Comm: pimd Tainted: G     U             6.8.0-6wind-knet #1
[   86.311027] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.1-0-g0551a4be2c-prebuilt.qemu-project.org 04/01/2014
[   86.312728] RIP: 0010:ip_mr_forward (/build/work/knet/net/ipv4/ipmr.c:1985)
[ 86.313399] Code: f9 1f 0f 87 85 03 00 00 48 8d 04 5b 48 8d 04 83 49 8d 44 c5 00 48 8b 40 70 48 39 c2 0f 84 d9 00 00 00 49 8b 46 58 48 83 e0 fe <80> b8 92 00 00 00 00 0f 84 55 ff ff ff 49 83 47 38 01 45 85 e4 0f
[   86.316565] RSP: 0018:ffffad21c0583ae0 EFLAGS: 00010246
[   86.317497] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   86.318596] RDX: ffff9559cb46c000 RSI: 0000000000000000 RDI: 0000000000000000
[   86.319627] RBP: ffffad21c0583b30 R08: 0000000000000000 R09: 0000000000000000
[   86.320650] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
[   86.321672] R13: ffff9559c093a000 R14: ffff9559cc00b800 R15: ffff9559c09c1d80
[   86.322873] FS:  00007f85db661980(0000) GS:ffff955a79d00000(0000) knlGS:0000000000000000
[   86.324291] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   86.325314] CR2: 0000000000000092 CR3: 000000002f13a000 CR4: 0000000000350ef0
[   86.326589] Call Trace:
[   86.327036]  <TASK>
[   86.327434] ? show_regs (/build/work/knet/arch/x86/kernel/dumpstack.c:479)
[   86.328049] ? __die (/build/work/knet/arch/x86/kernel/dumpstack.c:421 /build/work/knet/arch/x86/kernel/dumpstack.c:434)
[   86.328508] ? page_fault_oops (/build/work/knet/arch/x86/mm/fault.c:707)
[   86.329107] ? do_user_addr_fault (/build/work/knet/arch/x86/mm/fault.c:1264)
[   86.329756] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223)
[   86.330350] ? __irq_work_queue_local (/build/work/knet/kernel/irq_work.c:111 (discriminator 1))
[   86.331013] ? exc_page_fault (/build/work/knet/./arch/x86/include/asm/paravirt.h:693 /build/work/knet/arch/x86/mm/fault.c:1515 /build/work/knet/arch/x86/mm/fault.c:1563)
[   86.331702] ? asm_exc_page_fault (/build/work/knet/./arch/x86/include/asm/idtentry.h:570)
[   86.332468] ? ip_mr_forward (/build/work/knet/net/ipv4/ipmr.c:1985)
[   86.333183] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223)
[   86.333920] ipmr_mfc_add (/build/work/knet/./include/linux/rcupdate.h:782 /build/work/knet/net/ipv4/ipmr.c:1009 /build/work/knet/net/ipv4/ipmr.c:1273)
[   86.334583] ? __pfx_ipmr_hash_cmp (/build/work/knet/net/ipv4/ipmr.c:363)
[   86.335357] ip_mroute_setsockopt (/build/work/knet/net/ipv4/ipmr.c:1470)
[   86.336135] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223)
[   86.336854] ? ip_mroute_setsockopt (/build/work/knet/net/ipv4/ipmr.c:1470)
[   86.337679] do_ip_setsockopt (/build/work/knet/net/ipv4/ip_sockglue.c:944)
[   86.338408] ? __pfx_unix_stream_read_actor (/build/work/knet/net/unix/af_unix.c:2862)
[   86.339232] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223)
[   86.339809] ? aa_sk_perm (/build/work/knet/security/apparmor/include/cred.h:153 /build/work/knet/security/apparmor/net.c:181)
[   86.340342] ip_setsockopt (/build/work/knet/net/ipv4/ip_sockglue.c:1415)
[   86.340859] raw_setsockopt (/build/work/knet/net/ipv4/raw.c:836)
[   86.341408] ? security_socket_setsockopt (/build/work/knet/security/security.c:4561 (discriminator 13))
[   86.342116] sock_common_setsockopt (/build/work/knet/net/core/sock.c:3716)
[   86.342747] do_sock_setsockopt (/build/work/knet/net/socket.c:2313)
[   86.343363] __sys_setsockopt (/build/work/knet/./include/linux/file.h:32 /build/work/knet/net/socket.c:2336)
[   86.344020] __x64_sys_setsockopt (/build/work/knet/net/socket.c:2340)
[   86.344766] do_syscall_64 (/build/work/knet/arch/x86/entry/common.c:52 /build/work/knet/arch/x86/entry/common.c:83)
[   86.345433] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223)
[   86.346161] ? syscall_exit_work (/build/work/knet/./include/linux/audit.h:357 /build/work/knet/kernel/entry/common.c:160)
[   86.346938] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223)
[   86.347657] ? syscall_exit_to_user_mode (/build/work/knet/kernel/entry/common.c:215)
[   86.348538] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223)
[   86.349262] ? do_syscall_64 (/build/work/knet/./arch/x86/include/asm/cpufeature.h:171 /build/work/knet/arch/x86/entry/common.c:98)
[   86.349971] entry_SYSCALL_64_after_hwframe (/build/work/knet/arch/x86/entry/entry_64.S:129)

The original packet in ipmr_cache_report() may be queued and then forwarded
with ip_mr_forward(). This last function has the assumption that the skb
dst is set.

After the below commit, the skb dst is dropped by ipv4_pktinfo_prepare(),
which causes the oops.

Fixes: bb7403655b3c ("ipmr: support IP_PKTINFO on cache report IGMP msg")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240125141847.1931933-1-nicolas.dichtel@6wind.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>