linux-stable.git/net/ipv4/ip_output.c, branch linux-6.12.y

xfrm: esp: avoid in-place decrypt on shared skb frags

2026-05-08T06:39:25+00:00

commit f4c50a4034e62ab75f1d5cdd191dd5f9c77fdff4 upstream.

MSG_SPLICE_PAGES can attach pages from a pipe directly to an skb. TCP
marks such skbs with SKBFL_SHARED_FRAG after skb_splice_from_iter(),
so later paths that may modify packet data can first make a private
copy. The IPv4/IPv6 datagram append paths did not set this flag when
splicing pages into UDP skbs.

That leaves an ESP-in-UDP packet made from shared pipe pages looking
like an ordinary uncloned nonlinear skb. ESP input then takes the no-COW
fast path for uncloned skbs without a frag_list and decrypts in place
over data that is not owned privately by the skb.

Mark IPv4/IPv6 datagram splice frags with SKBFL_SHARED_FRAG, matching
TCP. Also make ESP input fall back to skb_cow_data() when the flag is
present, so ESP does not decrypt externally backed frags in place.
Private nonlinear skb frags still use the existing fast path.

This intentionally does not change ESP output. In esp_output_head(),
the path that appends the ESP trailer to existing skb tailroom without
calling skb_cow_data() is not reachable for nonlinear skbs:
skb_tailroom() returns zero when skb->data_len is nonzero, while ESP
tailen is positive. Thus ESP output will either use the separate
destination-frag path or fall back to skb_cow_data().

Fixes: cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible")
Fixes: 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible")
Fixes: 7da0dde68486 ("ip, udp: Support MSG_SPLICE_PAGES")
Fixes: 6d8192bd69bb ("ip6, udp6: Support MSG_SPLICE_PAGES")
Reported-by: Hyunwoo Kim 
Reported-by: Kuan-Ting Chen 
Tested-by: Hyunwoo Kim 
Cc: stable@vger.kernel.org
Signed-off-by: Kuan-Ting Chen 
Signed-off-by: Steffen Klassert 
Signed-off-by: Greg Kroah-Hartman

net: Add locking to protect skb->dev access in ip_output

2025-10-23T14:20:45+00:00

[ Upstream commit 1dbf1d590d10a6d1978e8184f8dfe20af22d680a ]

In ip_output() skb->dev is updated from the skb_dst(skb)->dev
this can become invalid when the interface is unregistered and freed,

Introduced new skb_dst_dev_rcu() function to be used instead of
skb_dst_dev() within rcu_locks in ip_output.This will ensure that
all the skb's associated with the dev being deregistered will
be transnmitted out first, before freeing the dev.

Given that ip_output() is called within an rcu_read_lock()
critical section or from a bottom-half context, it is safe to introduce
an RCU read-side critical section within it.

Multiple panic call stacks were observed when UL traffic was run
in concurrency with device deregistration from different functions,
pasting one sample for reference.

[496733.627565][T13385] Call trace:
[496733.627570][T13385] bpf_prog_ce7c9180c3b128ea_cgroupskb_egres+0x24c/0x7f0
[496733.627581][T13385] __cgroup_bpf_run_filter_skb+0x128/0x498
[496733.627595][T13385] ip_finish_output+0xa4/0xf4
[496733.627605][T13385] ip_output+0x100/0x1a0
[496733.627613][T13385] ip_send_skb+0x68/0x100
[496733.627618][T13385] udp_send_skb+0x1c4/0x384
[496733.627625][T13385] udp_sendmsg+0x7b0/0x898
[496733.627631][T13385] inet_sendmsg+0x5c/0x7c
[496733.627639][T13385] __sys_sendto+0x174/0x1e4
[496733.627647][T13385] __arm64_sys_sendto+0x28/0x3c
[496733.627653][T13385] invoke_syscall+0x58/0x11c
[496733.627662][T13385] el0_svc_common+0x88/0xf4
[496733.627669][T13385] do_el0_svc+0x2c/0xb0
[496733.627676][T13385] el0_svc+0x2c/0xa4
[496733.627683][T13385] el0t_64_sync_handler+0x68/0xb4
[496733.627689][T13385] el0t_64_sync+0x1a4/0x1a8

Changes in v3:
- Replaced WARN_ON() with  WARN_ON_ONCE(), as suggested by Willem de Bruijn.
- Dropped legacy lines mistakenly pulled in from an outdated branch.

Changes in v2:
- Addressed review comments from Eric Dumazet
- Used READ_ONCE() to prevent potential load/store tearing
- Added skb_dst_dev_rcu() and used along with rcu_read_lock() in ip_output

Signed-off-by: Sharath Chandra Vurukala 
Reviewed-by: Eric Dumazet 
Link: https://patch.msgid.link/20250730105118.GA26100@hu-sharathv-hyd.qualcomm.com
Signed-off-by: Jakub Kicinski 
Stable-dep-of: 833d4313bc1e ("mptcp: reset blackhole on success with non-loopback ifaces")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ipv4: adopt dst_dev, skb_dst_dev and skb_dst_dev_net[_rcu]

2025-10-23T14:20:45+00:00

[ Upstream commit a74fc62eec155ca5a6da8ff3856f3dc87fe24558 ]

Use the new helpers as a first step to deal with
potential dst->dev races.

Signed-off-by: Eric Dumazet 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20250630121934.3399505-8-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Stable-dep-of: 833d4313bc1e ("mptcp: reset blackhole on success with non-loopback ifaces")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ipv4: Unmask upper DSCP bits in __ip_queue_xmit()

2024-09-04T23:57:11+00:00

The function is passed the full DS field in its 'tos' argument by its
two callers. It then masks the upper DSCP bits using RT_TOS() when
passing it to ip_route_output_ports().

Unmask the upper DSCP bits when passing 'tos' to ip_route_output_ports()
so that in the future it could perform the FIB lookup according to the
full DSCP value.

Signed-off-by: Ido Schimmel 
Reviewed-by: Guillaume Nault 
Reviewed-by: David Ahern 
Link: https://patch.msgid.link/20240903135327.2810535-2-idosch@nvidia.com
Signed-off-by: Jakub Kicinski

ipv4: Unmask upper DSCP bits in ip_send_unicast_reply()

2024-08-31T16:44:51+00:00

The function calls flowi4_init_output() to initialize an IPv4 flow key
with which it then performs a FIB lookup using ip_route_output_flow().

'arg->tos' with which the TOS value in the IPv4 flow key (flowi4_tos) is
initialized contains the full DS field. Unmask the upper DSCP bits so
that in the future the FIB lookup could be performed according to the
full DSCP value.

Signed-off-by: Ido Schimmel 
Reviewed-by: Guillaume Nault 
Signed-off-by: David S. Miller

l2tp: use skb_queue_purge in l2tp_ip_destroy_sock

2024-08-20T23:52:28+00:00

Recent commit ed8ebee6def7 ("l2tp: have l2tp_ip_destroy_sock use
ip_flush_pending_frames") was incorrect in that l2tp_ip does not use
socket cork and ip_flush_pending_frames is for sockets that do. Use
__skb_queue_purge instead and remove the unnecessary lock.

Also unexport ip_flush_pending_frames since it was originally exported
in commit 4ff8863419cd ("ipv4: export ip_flush_pending_frames") for
l2tp and is not used by other modules.

Suggested-by: xiyou.wangcong@gmail.com
Signed-off-by: James Chapman 
Reviewed-by: Eric Dumazet 
Link: https://patch.msgid.link/20240819143333.3204957-1-jchapman@katalix.com
Signed-off-by: Jakub Kicinski

ipv4: export ip_flush_pending_frames

2024-07-31T08:25:12+00:00

To avoid protocol modules implementing their own, export
ip_flush_pending_frames.

Signed-off-by: James Chapman 
Signed-off-by: Tom Parkin 
Signed-off-by: David S. Miller

net: Add additional bit to support clockid_t timestamp type

2024-05-23T21:14:36+00:00

tstamp_type is now set based on actual clockid_t compressed
into 2 bits.

To make the design scalable for future needs this commit bring in
the change to extend the tstamp_type:1 to tstamp_type:2 to support
other clockid_t timestamp.

We now support CLOCK_TAI as part of tstamp_type as part of this
commit with existing support CLOCK_MONOTONIC and CLOCK_REALTIME.

Signed-off-by: Abhishek Chauhan 
Reviewed-by: Willem de Bruijn 
Reviewed-by: Martin KaFai Lau 
Link: https://lore.kernel.org/r/20240509211834.3235191-3-quic_abchauha@quicinc.com
Signed-off-by: Martin KaFai Lau

net: Rename mono_delivery_time to tstamp_type for scalabilty

2024-05-23T21:14:23+00:00

mono_delivery_time was added to check if skb->tstamp has delivery
time in mono clock base (i.e. EDT) otherwise skb->tstamp has
timestamp in ingress and delivery_time at egress.

Renaming the bitfield from mono_delivery_time to tstamp_type is for
extensibilty for other timestamps such as userspace timestamp
(i.e. SO_TXTIME) set via sock opts.

As we are renaming the mono_delivery_time to tstamp_type, it makes
sense to start assigning tstamp_type based on enum defined
in this commit.

Earlier we used bool arg flag to check if the tstamp is mono in
function skb_set_delivery_time, Now the signature of the functions
accepts tstamp_type to distinguish between mono and real time.

Also skb_set_delivery_type_by_clockid is a new function which accepts
clockid to determine the tstamp_type.

In future tstamp_type:1 can be extended to support userspace timestamp
by increasing the bitfield.

Signed-off-by: Abhishek Chauhan 
Reviewed-by: Willem de Bruijn 
Reviewed-by: Martin KaFai Lau 
Link: https://lore.kernel.org/r/20240509211834.3235191-2-quic_abchauha@quicinc.com
Signed-off-by: Martin KaFai Lau

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

2024-05-02T19:06:25+00:00

Cross-merge networking fixes after downstream PR.

Conflicts:

include/linux/filter.h
kernel/bpf/core.c
  66e13b615a0c ("bpf: verifier: prevent userspace memory access")
  d503a04f8bc0 ("bpf: Add support for certain atomics in bpf_arena to x86 JIT")
https://lore.kernel.org/all/20240429114939.210328b0@canb.auug.org.au/

No adjacent changes.

Signed-off-by: Jakub Kicinski