xfrm_hash_rebuild()'s first loop preallocates the bins/chains the reinsert
loop needs, so the reinsert (after hlist_del_rcu()) cannot allocate or
fail. But its guard is inverted: it skips policies with prefixlen <
threshold and preallocates for the rest.
prefixlen < threshold is exactly when policy_hash_bysel() returns NULL and
the reinsert takes the allocating xfrm_policy_inexact_insert() path. So the
loop preallocates for the exact policies (which never allocate) and skips
the inexact ones, whose bin/node is then allocated GFP_ATOMIC during
reinsert. On failure the error path only WARN_ONCE()s and continues,
leaving a poisoned bydst node; the next rebuild's hlist_del_rcu()
dereferences LIST_POISON2 and takes a GPF. Reachable under memory pressure,
deterministic via failslab.
Invert the guard so preallocation covers exactly the reinserted policies;
the reinsert then allocates nothing and cannot fail.
Crash:
Oops: general protection fault, probably for non-canonical address
0xfbd59c0000000024: 0000 [#1] SMP KASAN NOPTI
KASAN: maybe wild-memory-access in range [0xdead...]
...
Workqueue: events xfrm_hash_rebuild
RIP: 0010:xfrm_hash_rebuild+0x5b3/0x1190
RAX: dead000000000122 (LIST_POISON2 + offset)
...
Call Trace:
hlist_del_rcu (include/linux/rculist.h:599)
xfrm_hash_rebuild (net/xfrm/xfrm_policy.c:1365)
process_one_work (kernel/workqueue.c:3322)
worker_thread (kernel/workqueue.c:3486)
kthread (kernel/kthread.c:436)
ret_from_fork (arch/x86/kernel/process.c:158)
ret_from_fork_asm (arch/x86/entry/entry_64.S:245)
...
Kernel panic - not syncing: Fatal exception in interrupt
Fixes: 24969facd7 ("xfrm: policy: store inexact policies in an rhashtable")
Reported-by: AutonomousCodeSecurity@microsoft.com
Signed-off-by: Xiang Mei (Microsoft) <xmei5@asu.edu>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
When iptfs_skb_add_frags() copies frag references from the source
frag walk into a new SKB, it increments the page reference count via
__skb_frag_ref() but does not propagate SKBFL_SHARED_FRAG to the
destination SKB's skb_shinfo->flags.
If the source SKB carries shared frags (e.g. from a page-pool backed
receive path), the new inner SKB will appear to ESP as having privately
owned frags. A subsequent esp_input() call for a nested transport-mode
SA then takes the no-COW fast path and decrypts in place, writing over
pages that are still referenced by the outer IPTFS SKB. This causes
kernel-visible memory corruption and can trigger a panic.
All other frag-transfer helpers in the kernel (skb_try_coalesce,
skb_gro_receive, __pskb_copy_fclone, skb_shift, skb_segment) correctly
propagate SKBFL_SHARED_FRAG; align iptfs_skb_add_frags() with this
convention by setting the flag inside the loop immediately after
__skb_frag_ref() and nr_frags++, so every exit path that attaches a frag
unconditionally propagates SKBFL_SHARED_FRAG.
Fixes: 5f2b6a9095 ("xfrm: iptfs: add skb-fragment sharing code")
Signed-off-by: Chen YanJun <moomichen@tencent.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
xfrm_state_gc_task can run long after a failed IPTFS state setup. In the
reproduced case, __xfrm_init_state() cached x->mode_cbs, IPTFS setup
returned -ENOMEM before publishing mode_data, and the temporary module
reference from xfrm_get_mode_cbs() was dropped immediately. The dead state
then kept x->mode_cbs until deferred GC ran after xfrm_iptfs had been
unloaded.
Clear x->mode_cbs when mode init or clone fails before publishing
mode_data. Those states never installed mode-specific state or the
long-term IPTFS module pin, so deferred GC has nothing mode-specific to
destroy and must not retain a callback table pointer past the temporary
lookup reference.
The buggy scenario involves two paths, with each column showing the order
within that path:
failed setup path:
1. cache x->mode_cbs
2. mode setup fails before mode_data
3. drop the temporary module ref
4. dead state keeps x->mode_cbs cached
GC/unload path:
1. xfrm_state_put() queues GC work
2. xfrm_iptfs unloads later
3. xfrm_state_gc_task runs
4. GC dereferences stale x->mode_cbs
This also covers the failed clone path where clone_state() returns before
publishing mode_data.
Validation reproduced this kernel report:
Kernel panic - not syncing: Fatal exception
CONFIG_FAULT_INJECTION_STACKTRACE_FILTER=y
failslab_stacktrace_filter matched xfrm_iptfs frames
ack_error=-12
FAULT_INJECTION: forcing a failure
BUG: unable to handle page fault
Workqueue: events xfrm_state_gc_task
RIP: xfrm_state_gc_task+0x142/0x650
Modules linked in: esp4_offload xfrm_user [last unloaded: xfrm_iptfs]
Kernel panic - not syncing: Fatal exception
Fixes: 4b3faf610c ("xfrm: iptfs: add new iptfs xfrm mode impl")
Assisted-by: Codex:gpt-5.5
Signed-off-by: Cen Zhang <zzzccc427@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
copy_to_user_state_extra() only holds a reference to the outer xfrm_state.
That does not pin x->xso.dev. NETDEV_DOWN and NETDEV_UNREGISTER can race
through xfrm_dev_state_flush(), xfrm_state_delete(), and
xfrm_dev_state_free(), which clears xso->dev and drops the netdev
reference before the GETSA dump reaches xso_to_xuo() and reads
xso->dev->ifindex.
The buggy scenario involves two paths, with each column showing the order
within that path:
XFRM_MSG_GETSA dump path: NETDEV teardown path:
1. xfrm_get_sa() gets xfrm_state 1. xfrm_dev_state_flush() finds x
2. copy_to_user_state_extra() sees 2. xfrm_state_delete() removes x
x->xso.dev from the SAD
3. copy_user_offload() calls 3. xfrm_dev_state_free() clears
xso_to_xuo() xso->dev
4. xso->dev->ifindex dereferences 4. netdev_put() drops the device
a detached net_device reference
Avoid following the live net_device from the dump paths. Cache the
attached ifindex in xfrm_dev_offload when state or policy offload is bound
to a device, and serialize that snapshot instead. This preserves the
user-visible XFRMA_OFFLOAD_DEV value without depending on the embedded
net_device lifetime.
Validation reproduced this kernel report:
Oops: general protection fault
Call Trace:
<TASK>
copy_to_user_state_extra+0xb8d/0x1370 [xfrm_user]
? __pfx_copy_to_user_state_extra+0x10/0x10 [xfrm_user]
? __asan_memset+0x23/0x50
? srso_alias_return_thunk+0x5/0xfbef5
? __alloc_skb+0x342/0x960
? srso_alias_return_thunk+0x5/0xfbef5
? __asan_memset+0x23/0x50
? srso_alias_return_thunk+0x5/0xfbef5
? __nlmsg_put+0x147/0x1b0
dump_one_state+0x1c7/0x3e0 [xfrm_user]
xfrm_state_netlink+0xcb/0x130 [xfrm_user]
? __pfx_xfrm_state_netlink+0x10/0x10 [xfrm_user]
? srso_alias_return_thunk+0x5/0xfbef5
? xfrm_user_state_lookup.constprop.0+0x230/0x310 [xfrm_user]
xfrm_get_sa+0x102/0x250 [xfrm_user]
? __pfx_xfrm_get_sa+0x10/0x10 [xfrm_user]
xfrm_user_rcv_msg+0x504/0xaa0 [xfrm_user]
? __pfx_xfrm_user_rcv_msg+0x10/0x10 [xfrm_user]
? srso_alias_return_thunk+0x5/0xfbef5
? stack_trace_save+0x8e/0xc0
? __pfx_stack_trace_save+0x10/0x10
netlink_rcv_skb+0x11f/0x350
? __pfx_xfrm_user_rcv_msg+0x10/0x10 [xfrm_user]
? __pfx_netlink_rcv_skb+0x10/0x10
? __pfx_mutex_lock+0x10/0x10
? srso_alias_return_thunk+0x5/0xfbef5
xfrm_netlink_rcv+0x65/0x80 [xfrm_user]
netlink_unicast+0x600/0x870
? __pfx_netlink_unicast+0x10/0x10
? srso_alias_return_thunk+0x5/0xfbef5
? __pfx_stack_trace_save+0x10/0x10
netlink_sendmsg+0x75d/0xc10
? __pfx_netlink_sendmsg+0x10/0x10
? srso_alias_return_thunk+0x5/0xfbef5
____sys_sendmsg+0x77a/0x900
? srso_alias_return_thunk+0x5/0xfbef5
? __pfx_____sys_sendmsg+0x10/0x10
? __pfx_copy_msghdr_from_user+0x10/0x10
? release_sock+0x1a/0x1d0
? srso_alias_return_thunk+0x5/0xfbef5
? netlink_insert+0x143/0xec0
___sys_sendmsg+0xff/0x180
? __pfx____sys_sendmsg+0x10/0x10
? _raw_spin_lock_irqsave+0x85/0xe0
? do_getsockname+0xf9/0x170
? srso_alias_return_thunk+0x5/0xfbef5
? fdget+0x53/0x3b0
__sys_sendmsg+0x111/0x1a0
? __pfx___sys_sendmsg+0x10/0x10
? srso_alias_return_thunk+0x5/0xfbef5
? __sys_getsockname+0x8c/0x100
do_syscall_64+0x102/0x5a0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Fixes: 07b87f9eea ("xfrm: Fix unregister netdevice hang on hardware offload.")
Assisted-by: Codex:gpt-5.5
Signed-off-by: Cen Zhang <zzzccc427@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
xfrm_user_policy() clears the socket dst cache with __sk_dst_reset(),
i.e. the non-atomic __sk_dst_set(sk, NULL): it reads sk_dst_cache with
rcu_dereference_protected(), stores NULL and dst_release()s the old dst.
That is only safe if no other thread modifies sk_dst_cache concurrently.
For a connected UDP socket that does not hold: the transmit fast path
(udp_sendmsg -> sk_dst_check -> sk_dst_reset) resets the cache locklessly
with an atomic xchg(). A per-socket policy change racing a send can make
both sides observe the same old dst and each dst_release() it, dropping
the socket's single reference twice and freeing the xfrm_dst bundle while
it is still referenced:
BUG: KASAN: slab-use-after-free in dst_release
Write of size 4 at addr ffff88801897b6c0 by task exploit/155
Call Trace:
...
dst_release (... ./include/linux/rcuref.h:109)
xfrm_user_policy (./include/net/sock.h:2239 ./include/net/sock.h:2256 net/xfrm/xfrm_state.c:3053)
do_ip_setsockopt (net/ipv4/ip_sockglue.c:1347)
ip_setsockopt (net/ipv4/ip_sockglue.c:1417)
do_sock_setsockopt (net/socket.c:2368)
__sys_setsockopt (net/socket.c:2393)
__x64_sys_setsockopt (net/socket.c:2396)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
Reachable by an unprivileged user via a user+network namespace.
Use the atomic sk_dst_reset() so the cache is cleared and released with a
single xchg(): whichever side wins releases the dst once, the other sees
NULL and does nothing. Behaviour is otherwise unchanged.
Fixes: 2b06cdf3e6 ("xfrm: Clear sk_dst_cache when applying per-socket policy.")
Fixes: be8f8284cd ("net: xfrm: allow clearing socket xfrm policies.")
Reported-by: AutonomousCodeSecurity@microsoft.com
Signed-off-by: Xiang Mei (Microsoft) <xmei5@asu.edu>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
nat_keepalive_send() frees the keepalive skb whenever the IPv4 or IPv6
send helper reports an error.
That cleanup is only correct before the skb is handed to the output
path. Once ip_build_and_send_pkt() or ip6_xmit() takes ownership, the
networking stack may already have consumed the skb before returning an
error, so freeing it again is unsafe.
Handle the pre-handoff failure cases inside nat_keepalive_send_ipv4()
and nat_keepalive_send_ipv6(), where the caller still owns the skb, and
keep nat_keepalive_send() responsible only for family dispatch and the
unsupported-family cleanup path.
Fixes: f531d13bdf ("xfrm: support sending NAT keepalives in ESP in UDP states")
Cc: stable@vger.kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Signed-off-by: Qianyu Luo <qianyuluo3@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Reviewed-by: Eyal Birger <eyal.birger@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
skb_gso_segment() leaves the segment list head with ->prev pointing at
the last segment, an invariant validate_xmit_skb_list() relies on when
it sets its tail pointer (tail = skb->prev).
When validate_xmit_xfrm() walks a GSO list and some segments are stolen
by async crypto (->xmit() returns -EINPROGRESS), those segments are
unlinked from the list but the head ->prev is never updated. If the
last segment is the one stolen, the returned head still has ->prev
pointing at it, even though it is now owned by the crypto engine and may
be freed. validate_xmit_skb_list() later does tail->next = skb, writing
through that stale pointer -- a use-after-free.
Repoint skb->prev at the last retained segment before returning.
Fixes: f53c723902 ("net: Add asynchronous callbacks for xfrm on layer 2.")
Signed-off-by: Petr Wozniak <petr.wozniak@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
validate_xmit_xfrm() returns NULL both when a packet is dropped and
when it is stolen by async crypto (-EINPROGRESS from ->xmit()).
Callers cannot distinguish the two cases.
f53c723902 ("net: Add asynchronous callbacks for xfrm on layer 2.")
changed the semantics of a NULL return from "dropped" to "stolen or
dropped", but __dev_queue_xmit() was not updated. On virtual/bridge
interfaces (noqueue qdisc) __dev_queue_xmit() initialises rc=-ENOMEM
and jumps to out: when skb is NULL, returning -ENOMEM to the caller
even though the packet will be delivered correctly via xfrm_dev_resume().
Return ERR_PTR(-EINPROGRESS) from validate_xmit_xfrm() for the async
case so callers can tell it apart from a real drop. Update
__dev_queue_xmit() to handle ERR_PTR(-EINPROGRESS) from
validate_xmit_skb() correctly. Update validate_xmit_skb_list() to
use IS_ERR_OR_NULL() so that ERR_PTR(-EINPROGRESS) is not mistakenly
added to the transmitted list.
Fixes: f53c723902 ("net: Add asynchronous callbacks for xfrm on layer 2.")
Suggested-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Petr Wozniak <petr.wozniak@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
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Merge tag 'ipsec-2026-06-22' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec
Steffen Klassert says:
====================
pull request (net): ipsec 2026-06-22
1) xfrm: use compat translator only for u64 alignment mismatch
Gate the XFRM_USER_COMPAT translator on COMPAT_FOR_U64_ALIGNMENT
so 32-bit compat tasks on arches whose 32-bit ABI already matches
the native 64-bit layout are no longer rejected with -EOPNOTSUPP.
From Sanman Pradhan.
2) net: af_key: initialize alg_key_len for IPComp states
Initialize the alg_key_len to 0 in the IPComp branch of
pfkey_msg2xfrm_state() so an uninitialized value cannot drive
xfrm_alg_len() into a slab-out-of-bounds kmemdup during
XFRM_MSG_MIGRATE. From Zijing Yin.
3) xfrm: Fix dev use-after-free in xfrm async resumption
Stash the original skb->dev and extend the RCU critical section
across xfrm_rcv_cb() and transport_finish() to prevent a
tunnel-device UAF and original-device refcount leak when a
callback replaces skb->dev. From Dong Chenchen.
4) xfrm: Fix xfrm state cache insertion race
Move the state-validity check inside xfrm_state_lock in the
input state cache insertion path so a state cannot be killed
between the check and the insert. From Herbert Xu.
5) xfrm: annotate data-races around xfrm_policy_count[] and xfrm_policy_default[]
Add READ_ONCE()/WRITE_ONCE() annotations on xfrm_policy_count
and xfrm_policy_default to silence the KCSAN data race reported
on net->xfrm.policy_count. From Eric Dumazet.
6) espintcp: use sk_msg_free_partial to fix partial send
Replace the manual skmsg accounting in espintcp with
sk_msg_free_partial() so the skmsg stays consistent on every
iteration and the partial-send accounting bugs go away.
From Sabrina Dubroca.
7) xfrm: validate selector family and prefixlen during match
Reject mismatched address families in xfrm_selector_match() and
bound prefixlen in addr4_match()/addr_match() to prevent the
shift-out-of-bounds syzbot reported when an AF_UNSPEC selector
with a large prefixlen is matched against an IPv4 flow.
From Eric Dumazet.
* tag 'ipsec-2026-06-22' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec:
xfrm: validate selector family and prefixlen during match
espintcp: use sk_msg_free_partial to fix partial send
xfrm: annotate data-races around xfrm_policy_count[] and xfrm_policy_default[]
xfrm: Fix xfrm state cache insertion race
xfrm: Fix dev use-after-free in xfrm async resumption
net: af_key: initialize alg_key_len for IPComp states
xfrm: use compat translator only for u64 alignment mismatch
====================
Link: https://patch.msgid.link/20260622075726.29685-1-steffen.klassert@secunet.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
xfrmi_changelink() operates on at most two netns, dev_net(dev) and the
interface link netns xi->net. They differ once the device is created in
or moved to a netns other than the one the request runs in. The rtnl
changelink path checks CAP_NET_ADMIN only against dev_net(dev), so a
caller privileged there but not in xi->net can rewrite an interface that
lives in xi->net.
Gate xfrmi_changelink() on rtnl_dev_link_net_capable() at its top,
before any attribute is parsed.
Reported-by: Xiao Liang <shaw.leon@gmail.com>
Closes: https://lore.kernel.org/netdev/CABAhCOSzP1vaThGV35_VnsRCb=87_CPjPVsTHbq905k8A+BuUg@mail.gmail.com/
Fixes: f203b76d78 ("xfrm: Add virtual xfrm interfaces")
Cc: stable@vger.kernel.org
Signed-off-by: Maoyi Xie <maoyixie.tju@gmail.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260612085941.3158249-8-maoyixie.tju@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
syzbot reported a shift-out-of-bounds in xfrm_selector_match()
due to AF_UNSPEC selector with large prefixlen (e.g. 128) matched
against IPv4 flow (when XFRM_STATE_AF_UNSPEC is set).
Fix this by:
- Rejecting mismatched families in xfrm_selector_match.
- Returning false in addr4_match if prefixlen > 32.
- Returning false in addr_match if prefixlen > 128 (prevents overflow).
Fixes: 3f0ab59e65 ("xfrm: validate new SA's prefixlen using SA family when sel.family is unset")
Reported-by: syzbot+9383b1ff0df4b29ca5e6@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6a2fbe35.be3f099c.2836ae.0018.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
sk_msg_free_partial() ensures consistency of the skmsg at every
iteration, without having to manually handle uncharges and offsets.
This simplifies the code, and fixes some bugs in skmsg accounting when
we don't send the full contents.
Cc: stable@vger.kernel.org
Fixes: e27cca96cd ("xfrm: add espintcp (RFC 8229)")
Reported-by: Aaron Esau <aaron1esau@gmail.com>
Reported-by: Yiming Qian <yimingqian591@gmail.com>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
The xfrm input state cache insertion code checks the validity of
the state before acquiring the global xfrm_state_lock. Thus it's
possible for someone else to kill the state after it passed the
validity check, and then the insertion will add the dead state
to the cache.
Fix this by moving the validity check inside the lock.
This entire function is called on the input path, where BH must
be off (e.g., the caller of this function xfrm_input acquires
its spinlocks without disabling BH).
So there is no need to disable BH here or take the RCU read lock.
Remove both and replace them with an assertion that trips if BH
is accidentally enabled on some future calling path.
Fixes: 81a331a0e7 ("xfrm: Add an inbound percpu state cache.")
Reported-by: Zero Day Initiative <zdi-disclosures@trendmicro.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
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Merge tag 'ipsec-next-2026-06-12' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next
Steffen Klassert says:
====================
pull request (net-next): ipsec-next 2026-06-12
1) Replace the open-coded manual cleanup in xfrm_add_policy() error
path with xfrm_policy_destroy() for consistency with
xfrm_policy_construct().
From Deepanshu Kartikey.
2) Limit XFRMA_TFCPAD to a sensible maximum (max IP length, 64k) since
u32 is excessive for traffic flow confidentiality padding.
From David Ahern.
3) Add a new netlink message XFRM_MSG_MIGRATE_STATE that
allows migrating individual IPsec SAs independently of
their policies. The existing XFRM_MSG_MIGRATE is tightly coupled
to policy+SA migration, lacks SPI for unique SA identification,
and cannot express reqid changes or migrate Transport mode
selectors. The new interface identifies the SA via SPI and mark,
supports reqid changes, address family changes, encap removal,
and uses an atomic create+install flow under x->lock to prevent
SN/IV reuse during AEAD SA migration.
From Antony Antony.
* tag 'ipsec-next-2026-06-12' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next:
xfrm: add documentation for XFRM_MSG_MIGRATE_STATE
xfrm: restrict netlink attributes for XFRM_MSG_MIGRATE_STATE
xfrm: add XFRM_MSG_MIGRATE_STATE for single SA migration
xfrm: make xfrm_dev_state_add xuo parameter const
xfrm: extract address family and selector validation helpers
xfrm: refactor XFRMA_MTIMER_THRESH validation into a helper
xfrm: move encap and xuo into struct xfrm_migrate
xfrm: add error messages to state migration
xfrm: add state synchronization after migration
xfrm: check family before comparing addresses in migrate
xfrm: split xfrm_state_migrate into create and install functions
xfrm: rename reqid in xfrm_migrate
xfrm: fix NAT-related field inheritance in SA migration
xfrm: allow migration from UDP encapsulated to non-encapsulated ESP
xfrm: add extack to xfrm_init_state
xfrm: remove redundant assignments
xfrm: Reject excessive values for XFRMA_TFCPAD
xfrm: cleanup error path in xfrm_add_policy()
====================
Link: https://patch.msgid.link/20260612074725.1760473-1-steffen.klassert@secunet.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
xfrm async resumption hold skb->dev refcnt until after transport_finish.
However, xfrm_rcv_cb may modify skb->dev to tunnel dev without taking
device reference, such as vti_rcv_cb. The subsequent async resumption
will decrement the tunnel device's reference count, which lead to uaf
of tunnel dev and refcnt leak of orig dev as below:
unregister_netdevice: waiting for vti1 to become free. Usage count = -2
Stash the original skb->dev to fix refcnt imbalance. The new skb->dev set
by xfrm_rcv_cb can race with device teardown. Extend rcu protection over
xfrm_rcv_cb and transport_finish to prevent races.
Fixes: 1c428b0384 ("xfrm: hold dev ref until after transport_finish NF_HOOK")
Reported-by: Xu Chunxiao <xuchunxiao3@huawei.com>
Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
The XFRM compat layer (CONFIG_XFRM_USER_COMPAT) translates 32-bit xfrm
netlink and setsockopt messages into the native 64-bit layout. It is
only needed on architectures where the 32-bit and 64-bit ABIs disagree
on u64 alignment, which the kernel encodes as COMPAT_FOR_U64_ALIGNMENT.
That symbol is defined only by arch/x86. XFRM_USER_COMPAT depends on it,
so the translator can never be built on any other architecture,
including arm64, which still provides a 32-bit compat ABI (CONFIG_COMPAT)
for AArch32 EL0 userspace. On arm64 the AArch32 EABI already aligns u64
to 8 bytes, identical to the AArch64 ABI, so no translation is required
and the native code path is correct for 32-bit tasks.
However, xfrm_user_rcv_msg() and xfrm_user_policy() gate on
in_compat_syscall() alone and then call xfrm_get_translator(), which
returns NULL when no translator is registered. On arm64 that is always
the case, so every xfrm netlink message and the XFRM_POLICY setsockopt
issued by a 32-bit task returns -EOPNOTSUPP. A 32-bit userspace process
on arm64 (and on any other arch with CONFIG_COMPAT but without
COMPAT_FOR_U64_ALIGNMENT) therefore cannot configure XFRM state or
policy through the XFRM_USER netlink API, and cannot use the XFRM_POLICY
setsockopt path, because both fail before reaching the native parser.
The translator series replaced the blanket compat rejection with a
translator lookup. That made the path usable on x86 when the translator
is available, but left architectures that cannot build the translator
permanently rejected even when their compat layout already matches the
native layout. Let those architectures use the native parser instead.
Gate the translator requirement on COMPAT_FOR_U64_ALIGNMENT instead of
on in_compat_syscall() alone. Gating on the ABI property rather than on
CONFIG_XFRM_USER_COMPAT is deliberate: on x86 with IA32_EMULATION=y but
XFRM_USER_COMPAT=n, a 32-bit task must still be rejected rather than
routed through the native parser, which would misread genuinely
4-byte-aligned x86-32 messages. COMPAT_FOR_U64_ALIGNMENT is the ABI
property that makes the XFRM translator mandatory.
Only the receive/input direction needs the guard. The send, dump and
notification paths already call the translator as "if (xtr) { ... }"
with no error on NULL, so on arches without a translator they no-op and
the kernel emits native 64-bit-layout messages, which is what an AArch32
task expects.
Tested on Juniper SRX hardware: with the fix, 32-bit IPsec userspace
netlink and XFRM_POLICY setsockopt operations that previously failed
with -EOPNOTSUPP now succeed; x86 behaviour is unchanged by inspection.
Fixes: 5106f4a8ac ("xfrm/compat: Add 32=>64-bit messages translator")
Fixes: 96392ee5a1 ("xfrm/compat: Translate 32-bit user_policy from sockptr")
Cc: stable@vger.kernel.org
Signed-off-by: Sanman Pradhan <psanman@juniper.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
espintcp keeps a single in-flight transmit in ctx->partial.
Before building a new sk_msg, espintcp_sendmsg() first tries to flush
that state through espintcp_push_msgs().
For blocking callers, espintcp_push_msgs() may return success even when
the previous partial send is still pending. espintcp_sendmsg() would
then reinitialize emsg->skmsg and reuse ctx->partial while the old
transfer still owns that state.
Do not rebuild the send message when ctx->partial is still in progress.
If espintcp_push_msgs() returns with emsg->len still set, fail the new
send instead of overwriting the live partial state.
This is a memory-safety fix: reusing the live partial-send state can
leave a stale offset attached to a new sk_msg and lead to an out-of-
bounds read in the send path.
tcp_sendmsg_locked() already handles waiting for send buffer memory, so
the fix here is just to preserve espintcp's one-message-at-a-time
transmit state.
Fixes: e27cca96cd ("xfrm: add espintcp (RFC 8229)")
Cc: stable@kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Zhengchuan Liang <zcliangcn@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Assisted-by: Codex:GPT-5.4
Signed-off-by: Wyatt Feng <bronzed_45_vested@icloud.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
iptfs_destroy_state() calls hrtimer_cancel() while holding a spinlock
that the timer callback also acquires, leading to an ABBA deadlock on
SMP systems.
For the output timer (iptfs_timer):
- iptfs_destroy_state() holds x->lock, calls hrtimer_cancel()
- iptfs_delay_timer() callback takes x->lock
For the drop timer (drop_timer):
- iptfs_destroy_state() holds drop_lock, calls hrtimer_cancel()
- iptfs_drop_timer() callback takes drop_lock
Both timers use HRTIMER_MODE_REL_SOFT, so their callbacks run in softirq
context. When hrtimer_cancel() is called for a soft timer that is
currently executing on another CPU, hrtimer_cancel_wait_running() spins
on softirq_expiry_lock -- the same lock held by the softirq running the
callback. If the callback is blocked waiting for the spinlock held by
the caller of hrtimer_cancel(), a circular dependency forms:
CPU 0: holds lock_A -> waits for softirq_expiry_lock
CPU 1: holds softirq_expiry_lock -> waits for lock_A
Fix by calling hrtimer_cancel() before acquiring the respective locks.
hrtimer_cancel() is safe to call without holding any lock and will wait
for any in-progress callback to complete. For the output timer, the
lock is still acquired afterwards to drain the packet queue. For the
drop timer, the lock/unlock pair is removed entirely since it only
existed to serialize with the timer callback, which hrtimer_cancel()
already guarantees.
Found by source code audit.
Fixes: 4b3faf610c ("xfrm: iptfs: add new iptfs xfrm mode impl")
Cc: Christian Hopps <chopps@labn.net>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: stable@vger.kernel.org
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Only accept XFRMA used in this method, reject the rest.
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Add a new netlink method to migrate a single xfrm_state.
Unlike the existing migration mechanism (SA + policy), this
supports migrating only the SA and allows changing the reqid.
The SA is looked up via xfrm_usersa_id, which uniquely
identifies it, so old_saddr is not needed. old_daddr is carried in
xfrm_usersa_id.daddr.
The reqid is invariant in the old migration.
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
The xuo pointer is not modified by xfrm_dev_state_add(); make it const.
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Extract verify_xfrm_family() and verify_selector_prefixlen() from
verify_newsa_info() to allow reuse by other netlink handlers.
verify_xfrm_family() validates that a given address family is AF_INET
or AF_INET6 (with CONFIG_IPV6 guard).
verify_selector_prefixlen() validates that the selector prefix lengths
are within the bounds for the given address family.
No functional change.
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Extract verify_mtimer_thresh() to consolidate the XFRMA_MTIMER_THRESH
validation logic shared between the add_sa and upcoming patch.
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
In preparation for an upcoming patch, move the xfrm_encap_tmpl and
xfrm_user_offload pointers from separate parameters into struct
xfrm_migrate, reducing the parameter count of
xfrm_state_migrate_create(), xfrm_state_migrate_install()
and xfrm_state_migrate()
The fields are placed after the four xfrm_address_t members where
the struct is naturally 8-byte aligned, avoiding padding.
No functional change.
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Add descriptive(extack) error messages for all error paths
in state migration. This improves diagnostics by
providing clear feedback when migration fails.
After xfrm_init_state() use NL_SET_ERR_MSG_WEAK() as fallback for
error paths not yet propagating extack e.g. mode_cbs->init_state()
No functional change.
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Add xfrm_migrate_sync() to copy curlft and replay state from the old SA
to the new one before installation. The function allocates no memory, so
it can be called under a spinlock. In preparation for a subsequent patch
in this series.
A subsequent patch calls this under x->lock, atomically capturing the
latest lifetime counters and replay state from the original SA and
deleting it in the same critical section to prevent SN/IV reuse
for XFRM_MSG_MIGRATE_STATE method.
No functional change.
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
When migrating between different address families, xfrm_addr_equal()
cannot meaningfully compare addresses, different lengths.
Only call xfrm_addr_equal() when families match, and take
the xfrm_state_insert() path when addresses are equal.
Fixes: 80c9abaabf ("[XFRM]: Extension for dynamic update of endpoint address(es)")
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
To prepare for subsequent patches, split
xfrm_state_migrate() into two functions:
- xfrm_state_migrate_create(): creates the migrated state
- xfrm_state_migrate_install(): installs it into the state table
splitting will help to avoid SN/IV reuse when migrating AEAD SA.
And add const whenever possible.
No functional change.
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
In preparation for a later patch in this series s/reqid/old_reqid/.
No functional change.
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
During SA migration via xfrm_state_clone_and_setup(),
nat_keepalive_interval was silently dropped and never copied to the new
SA. mapping_maxage was unconditionally copied even when migrating to a
non-encapsulated SA.
Both fields are only meaningful when UDP encapsulation (NAT-T) is in
use. Move mapping_maxage and add nat_keepalive_interval inside the
existing if (encap) block, so both are inherited when migrating with
encapsulation and correctly absent when migrating without it.
Fixes: f531d13bdf ("xfrm: support sending NAT keepalives in ESP in UDP states")
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
The current code prevents migrating an SA from UDP encapsulation to
plain ESP. This is needed when moving from a NATed path to a non-NATed
one, for example when switching from IPv4+NAT to IPv6.
Only copy the existing encapsulation during migration if the encap
attribute is explicitly provided.
Note: PF_KEY's SADB_X_MIGRATE always passes encap=NULL and never
supported encapsulation in migration. PF_KEY is deprecated and was
in feature freeze when UDP encapsulation was added to xfrm.
Tested-by: Yan Yan <evitayan@google.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Add a struct extack parameter to xfrm_init_state() and pass it
through to __xfrm_init_state(). This allows validation errors detected
during state initialization to propagate meaningful error messages back
to userspace.
xfrm_state_migrate() now passes extack so that errors from the
XFRM_MSG_MIGRATE_STATE path are properly reported. Callers without an
extack context (af_key, ipcomp4, ipcomp6) pass NULL, preserving their
existing behaviour.
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
These assignments are overwritten within the same function further down
commit e8961c50ee ("xfrm: Refactor migration setup
during the cloning process")
x->props.family = m->new_family;
Which actually moved it in the
commit e03c3bba35 ("xfrm: Fix xfrm migrate issues when address family changes")
And the initial
commit 80c9abaabf ("[XFRM]: Extension for dynamic update of endpoint address(es)")
added x->props.saddr = orig->props.saddr; and
memcpy(&xc->props.saddr, &m->new_saddr, sizeof(xc->props.saddr));
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Fix the race by pruning the bin while still holding xfrm_policy_lock,
before dropping it. Use __xfrm_policy_inexact_prune_bin() directly since
the lock is already held. The wrapper xfrm_policy_inexact_prune_bin()
becomes unused and is removed.
Race:
CPU0 (XFRM_MSG_DELPOLICY) CPU1 (XFRM_MSG_NEWSPDINFO)
========================== ==========================
xfrm_policy_bysel_ctx():
spin_lock_bh(xfrm_policy_lock)
bin = xfrm_policy_inexact_lookup()
__xfrm_policy_unlink(pol)
spin_unlock_bh(xfrm_policy_lock)
xfrm_policy_kill(ret)
// wide window, lock not held
xfrm_hash_rebuild():
spin_lock_bh(xfrm_policy_lock)
__xfrm_policy_inexact_flush():
kfree_rcu(bin) // bin freed
spin_unlock_bh(xfrm_policy_lock)
xfrm_policy_inexact_prune_bin(bin)
// UAF: bin is freed
Fixes: 6be3b0db6d ("xfrm: policy: add inexact policy search tree infrastructure")
Signed-off-by: Sanghyun Park <sanghyun.park.cnu@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
__input_process_payload() stores first_skb into xtfs->ra_newskb under
drop_lock when starting partial reassembly, then unlocks and breaks out
of the processing loop. The post-loop check reads xtfs->ra_newskb
without the lock to decide whether first_skb is still owned:
if (first_skb && first_iplen && !defer && first_skb != xtfs->ra_newskb)
Between spin_unlock and this read, a concurrent CPU running
iptfs_reassem_cont() (or the drop_timer hrtimer) can complete
reassembly, NULL xtfs->ra_newskb, and free the skb. The check then
evaluates first_skb != NULL as true, and pskb_trim/ip_summed/consume_skb
operate on the freed skb — a use-after-free in skbuff_head_cache.
Replace the unlocked read with a local bool that records whether
first_skb was handed to the reassembly state in the current call. The
flag is set after the existing spin_unlock, before the break, using the
pointer equality that is stable at that point (first_skb == skb iff
first_skb was stored in ra_newskb).
Fixes: 3f3339885f ("xfrm: iptfs: add reusing received skb for the tunnel egress packet")
Signed-off-by: Zhenghang Xiao <kipreyyy@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
iptfs_consume_frags() transfers paged fragments from one socket buffer
to another but fails to propagate the SKBFL_SHARED_FRAG flag. This is
the same class of bug that was fixed in skb_try_coalesce() for
CVE-2026-46300: when fragments backed by read-only page-cache pages are
merged, the marker indicating their shared nature must be preserved so
that ESP can decide correctly whether in-place encryption is safe.
Apply the same two-line fix used in skb_try_coalesce() to
iptfs_consume_frags().
Fixes: b96ba312e2 ("xfrm: iptfs: share page fragments of inner packets")
Cc: stable@vger.kernel.org # 6.14+
Signed-off-by: Takao Sato <takaosato1997@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Transport-mode reinjection stores a struct net pointer in skb->cb and
uses it later from xfrm_trans_reinject(). That pointer must stay valid
until the deferred callback runs.
Take a netns reference when queueing deferred reinjection work and drop
it after the callback completes. Use maybe_get_net() so the queueing
path does not revive a namespace that is already being torn down.
This keeps the existing workqueue design and fixes the netns lifetime
handling in one place for all users of xfrm_trans_queue_net().
Fixes: 7b3801927e ("xfrm: introduce xfrm_trans_queue_net")
Cc: stable@kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Co-developed-by: Luxing Yin <tr0jan@lzu.edu.cn>
Signed-off-by: Luxing Yin <tr0jan@lzu.edu.cn>
Signed-off-by: Zhengchuan Liang <zcliangcn@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Assisted-by: Codex:gpt-5.4
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
The struct pernet_operations docstring in include/net/net_namespace.h
explicitly warns against blocking RCU primitives in .exit handlers:
Exit methods using blocking RCU primitives, such as
synchronize_rcu(), should be implemented via exit_batch.
[...]
Please, avoid synchronize_rcu() at all, where it's possible.
Note that a combination of pre_exit() and exit() can
be used, since a synchronize_rcu() is guaranteed between
the calls.
xfrm_policy_fini() violates this: it calls synchronize_rcu() before
freeing the policy_bydst hash tables (so no RCU reader is mid-
traversal at free time), but runs from xfrm_net_ops.exit -- once per
namespace -- so a cleanup_net() of N namespaces pays N full RCU
grace periods serially.
Use the documented pre_exit/exit split. Move the policy flush (and
the workqueue drains it depends on) into a new .pre_exit handler;
xfrm_policy_fini() then runs in .exit and frees the hash tables
after the synchronize_rcu_expedited() that cleanup_net() guarantees
between the two phases. Providing O(1) RCU grace periods per batch
instead of O(N).
Observed on Linux 6.18 with a workload doing unshare(CLONE_NEWNET)
at ~13/sec sustained: cleanup_net() and the netns_wq rescuer kthread
both stuck in xfrm_policy_fini()'s synchronize_rcu(), >300k struct
net accumulated in the cleanup queue, Percpu in /proc/meminfo climbed
to 130+ GB on 256-CPU hosts, and memcg OOMs followed. setup_net and
__put_net counts were balanced, ruling out a refcount leak.
Fixes: 069daad4f2 ("xfrm: Wait for RCU readers during policy netns exit")
Signed-off-by: Usama Arif <usama.arif@linux.dev>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
iptfs_clone_state() clones the IPTFS mode data with kmemdup(). This
copies runtime objects which must not be shared with the original SA,
including the embedded sk_buff_head, hrtimers, spinlock, and in-flight
reassembly/reorder state.
If xfrm_state_migrate() fails after clone_state() but before the later
init_state() call has reinitialized those fields, the cloned state can be
destroyed by xfrm_state_gc_task() with list and timer state copied from the
original SA. With queued packets this lets the clone splice and free skbs
owned by the original IPTFS queue, leading to use-after-free and
double-free reports in iptfs_destroy_state() and skb release paths.
Reinitialize the clone's runtime state before publishing it through
x->mode_data. Because clone_state() now publishes a destroyable mode_data
object before init_state(), take the mode callback module reference there.
Avoid taking it again from __iptfs_init_state() for the same object.
Fixes: 0e4fbf013f ("xfrm: iptfs: add user packet (tunnel ingress) handling")
Cc: stable@vger.kernel.org
Signed-off-by: Shaomin Chen <eeesssooo020@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
tfcpad is a u32, but that full range is excessive for padding.
Limit it to max IP length (64k).
Signed-off-by: David Ahern <dahern@nvidia.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Leo Lin reported OOB write issue in esp component:
xfrm_state_mtu() returns u32 but performs its arithmetic in unsigned
modulo-2^32 space using an attacker-influenced "header_len + authsize +
net_adj" subtracted from a small "mtu" argument. A nobody user can
install an IPv4 ESP tunnel SA with a large authentication key
(XFRMA_ALG_AUTH_TRUNC, e.g. hmac(sha512), 64-byte key, 64-byte trunc),
configure a small interface MTU (68 bytes), and set XFRMA_TFCPAD to a
large value. When a single UDP datagram is then sent through the
tunnel, xfrm_state_mtu() underflows to a near-2^32 value, and
esp_output() consumes it as a signed int via:
padto = min(x->tfcpad, xfrm_state_mtu(x, mtu_cached))
esp.tfclen = padto - skb->len (assigned to int)
esp.tfclen ends up negative (e.g. -207). It is sign-extended to size_t
when passed to memset() inside esp_output_fill_trailer(), producing a
~16 EB write of zeroes at skb_tail_pointer(skb). KASAN logs it as
"Write of size 18446744073709551537 at addr ffff888...".
Check for underflow and return 1. This causes the sendmsg attempt to
fail with ENETUNREACH.
Fixes: c5c2523893 ("[XFRM]: Optimize MTU calculation")
Reported-by: Leo Lin <leo@depthfirst.com>
Assisted-by: Codex:26.506.31004
Signed-off-by: David Ahern <dahern@nvidia.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Move the out_free_req label up by a couple of lines so that the
allocated dst SG list gets freed on error as well as success.
Fixes: eb2953d269 ("xfrm: ipcomp: Use crypto_acomp interface")
Cc: stable@kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Reported-by: Yilin Zhu <zylzyl2333@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
xfrm_send_migrate() in net/xfrm/xfrm_user.c and pfkey_send_migrate()
in net/key/af_key.c both hardcode &init_net for the multicast that
announces a successful XFRM_MSG_MIGRATE / SADB_X_MIGRATE.
XFRM_MSG_MIGRATE arrives on a per-netns NETLINK_XFRM socket, and the
rest of the xfrm/af_key netlink path was made netns-aware in 2008.
The other 14 multicast paths in xfrm_user.c route their event using
xs_net(x), xp_net(xp) or sock_net(skb->sk); only the migrate path
was missed.
Two consequences of the init_net hardcoding:
1. The notification (selector, old/new endpoint addresses, and the
km_address) is delivered to listeners on init_net's
XFRMNLGRP_MIGRATE / pfkey BROADCAST_ALL groups rather than on
the issuing netns. An IKE daemon running in init_net therefore
receives migration notifications originating from any other
netns on the host.
2. An IKE daemon running inside a non-init netns and subscribed
to its own XFRMNLGRP_MIGRATE / pfkey groups never receives the
notification of its own migration. IKEv2 MOBIKE / address-update
handling inside a netns is silently broken.
Thread struct net through km_migrate() and the xfrm_mgr.migrate
function pointer, drop the &init_net override in xfrm_send_migrate()
and pfkey_send_migrate(), and pass the caller's net (already in
scope in xfrm_migrate() via sock_net(skb->sk)) all the way down.
struct xfrm_mgr is in-tree only and not exported as a stable API,
so the function-pointer signature change is internal.
pfkey_broadcast() is already netns-aware via net_generic(net,
pfkey_net_id) since the pernet conversion. The five other
pfkey_broadcast() callers in af_key.c already pass xs_net(x),
sock_net(sk) or a per-netns net, so this only removes the
&init_net outlier.
Fixes: 5c79de6e79 ("[XFRM]: User interface for handling XFRM_MSG_MIGRATE")
Cc: stable@vger.kernel.org # v5.15+
Signed-off-by: Maoyi Xie <maoyi.xie@ntu.edu.sg>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
KASAN reproduces a slab-use-after-free in __xfrm_state_delete()'s
hlist_del_rcu calls under syzkaller load on linux-6.12.y stable
(reproduced on 6.12.47, also reachable via the same code path on
torvalds/master and on the ipsec tree). Nine unique signatures cluster
in the xfrm_state lifecycle, the load-bearing one being:
BUG: KASAN: slab-use-after-free in __hlist_del include/linux/list.h:990 [inline]
BUG: KASAN: slab-use-after-free in hlist_del_rcu include/linux/rculist.h:516 [inline]
BUG: KASAN: slab-use-after-free in __xfrm_state_delete net/xfrm/xfrm_state.c
Write of size 8 at addr ffff8881198bcb70 by task kworker/u8:9/435
Workqueue: netns cleanup_net
Call Trace:
__hlist_del / hlist_del_rcu
__xfrm_state_delete
xfrm_state_delete
xfrm_state_flush
xfrm_state_fini
ops_exit_list
cleanup_net
The other observed signatures hit the same slab object from
__xfrm_state_lookup, xfrm_alloc_spi, __xfrm_state_insert and an OOB
write variant of __xfrm_state_delete, all on the byseq/byspi
hash chains.
__xfrm_state_delete() guards its byseq and byspi unhashes with
value-based predicates:
if (x->km.seq)
hlist_del_rcu(&x->byseq);
if (x->id.spi)
hlist_del_rcu(&x->byspi);
while everywhere else in the file (e.g. state_cache, state_cache_input)
the safer hlist_unhashed() check is used. xfrm_alloc_spi() sets
x->id.spi = newspi inside xfrm_state_lock and then immediately inserts
into byspi, but a path that observes x->id.spi != 0 outside of
xfrm_state_lock can still skip-or-hit the byspi unhash inconsistently
with whether x is actually on the list. The same holds for x->km.seq
versus byseq, and the bydst/bysrc unhashes have no predicate at all,
so a second __xfrm_state_delete() on the same object writes through
LIST_POISON pprev.
The defensive change here:
- Use hlist_del_init_rcu() instead of hlist_del_rcu() on bydst,
bysrc, byseq and byspi so a second deletion is a no-op rather
than a write through LIST_POISON pprev. The byseq/byspi nodes
are already initialised in xfrm_state_alloc().
- Test hlist_unhashed() rather than the value predicate for
byseq/byspi, so the unhash decision tracks list state rather than
mutable scalar fields.
Empirical verification: applied this patch on top of v6.12.47, rebuilt,
and re-ran the same syzkaller harness for 1h16m on a previously-crashy
configuration that produced ~100 hits each of slab-use-after-free
Read in xfrm_alloc_spi / Read in __xfrm_state_lookup / Write in
__xfrm_state_delete. After the patch, 7.1M execs across 32 VMs at
~1550 exec/sec produced zero xfrm_state UAF/OOB hits. /proc/slabinfo
confirms the xfrm_state slab is actively allocated and freed during
the run (~143 KiB resident), so the fuzzer is still exercising those
code paths -- they just no longer crash.
Reproduction:
- Linux 6.12.47 x86_64 + KASAN_GENERIC + KASAN_INLINE + KCOV
- syzkaller @ 746545b8b1e4c3a128db8652b340d3df90ce61db
- 32 QEMU/KVM VMs x 2 vCPU on AWS c5.metal bare metal
- 9 unique signatures collected in ~9h, all within xfrm_state
lifecycle
Fixes: fe9f1d8779 ("xfrm: add state hashtable keyed by seq")
Fixes: 7b4dc3600e ("[XFRM]: Do not add a state whose SPI is zero to the SPI hash.")
Reported-by: Michal Kosiorek <mkosiorek121@gmail.com>
Tested-by: Michal Kosiorek <mkosiorek121@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Michal Kosiorek <mkosiorek121@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Replace the open-coded manual cleanup in the error path of
xfrm_add_policy() with xfrm_policy_destroy(), which already
handles all the necessary cleanup internally. This is consistent
with how xfrm_policy_construct() handles its own error paths.
The walk.dead flag must be set before calling xfrm_policy_destroy()
as required by BUG_ON(!policy->walk.dead).
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
The compat 64=>32 translation path handles XFRM_MSG_MAPPING, but
xfrm_msg_min[] does not provide the native payload size for this
message type.
Add the missing XFRM_MSG_MAPPING entry so compat translation can size
and translate mapping notifications correctly.
Fixes: 5461fc0c8d ("xfrm/compat: Add 64=>32-bit messages translator")
Cc: stable@kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Signed-off-by: Ruijie Li <ruijieli51@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
On VXLAN over IPsec egress, xfrm{4,6}_transport_output() blindly
overwrite inner_transport_header (== the inner TCP header saved in VXLAN
iptunnel_handle_offloads() -> skb_reset_inner_headers()) with the
current transport_header (== the VXLAN outer UDP header set by
udp_tunnel_xmit_skb()).
This was a latent bug, harmless until commit [1] added a doff validation
check in qdisc_pkt_len_segs_init() for encapsulated GSO packets. With
the wrong inner_transport_header set by xfrm, qdisc_pkt_len_segs_init()
interprets inner_transport_header as a TCP header, reads doff=0 from the
upper byte of the VNI and drops the packet with DROP_REASON_SKB_BAD_GSO.
Besides the use in GSO to determine the header size of segmented
packets, inner_transport_header might be used by drivers to set up
inner checksum offloading by pointing the HW to the inner transport
header. A quick browse through available drivers shows that mlx5 uses
skb->csum_start specifically for this scenario, while others either
don't support VXLAN over IPsec crypto offload (ixgbe) or the HW is
capable of parsing the packets itself (nfp, Chelsio).
But in all cases, it is more correct to let the inner_transport_header
point to the innermost header instead of overwriting it in xfrm.
So fix this by guarding all four inner header save sites in
xfrm_output.c (xfrm{4,6}_transport_output, xfrm{4,6}_tunnel_encap_add)
with a check for skb->inner_protocol. When inner_protocol is set, a
tunnel layer (VXLAN, Geneve, GRE, etc.) has already saved the correct
inner header offsets and they must not be overwritten. When
inner_protocol is zero, no prior tunnel encapsulation exists and xfrm
must save the inner headers itself. The tunnel mode checks are only
added for completion, since they aren't strictly required, as
xfrm_output() forces software GSO in tunnel mode before encap.
This makes the previously added test pass:
# ./tools/testing/selftests/drivers/net/hw/ipsec_vxlan.py
TAP version 13
1..4
ok 1 ipsec_vxlan.test_vxlan_ipsec_crypto_offload.outer_v4_inner_v4
ok 2 ipsec_vxlan.test_vxlan_ipsec_crypto_offload.outer_v4_inner_v6
ok 3 ipsec_vxlan.test_vxlan_ipsec_crypto_offload.outer_v6_inner_v4
ok 4 ipsec_vxlan.test_vxlan_ipsec_crypto_offload.outer_v6_inner_v6
# Totals: pass:4 fail:0 xfail:0 xpass:0 skip:0 error:0
[1] commit 7fb4c19670 ("net: pull headers in qdisc_pkt_len_segs_init()")
Fixes: f1bd7d659e ("xfrm: Add encapsulation header offsets while SKB is not encrypted")
Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
