linux-stable.git/net/netfilter/ipvs, branch linux-6.18.y Linux kernel stable tree ipvs: fix NULL deref in ip_vs_add_service error path 2026-04-22T11:22:22+00:00 Weiming Shi bestswngs@gmail.com 2026-04-01T07:58:01+00:00 a32dabacee111cea083ddd57a03635672e1bff29 [ Upstream commit 9a91797e61d286805ae10a92cc48959c30800556 ] When ip_vs_bind_scheduler() succeeds in ip_vs_add_service(), the local variable sched is set to NULL. If ip_vs_start_estimator() subsequently fails, the out_err cleanup calls ip_vs_unbind_scheduler(svc, sched) with sched == NULL. ip_vs_unbind_scheduler() passes the cur_sched NULL check (because svc->scheduler was set by the successful bind) but then dereferences the NULL sched parameter at sched->done_service, causing a kernel panic at offset 0x30 from NULL. Oops: general protection fault, [..] [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037] RIP: 0010:ip_vs_unbind_scheduler (net/netfilter/ipvs/ip_vs_sched.c:69) Call Trace: <TASK> ip_vs_add_service.isra.0 (net/netfilter/ipvs/ip_vs_ctl.c:1500) do_ip_vs_set_ctl (net/netfilter/ipvs/ip_vs_ctl.c:2809) nf_setsockopt (net/netfilter/nf_sockopt.c:102) [..] Fix by simply not clearing the local sched variable after a successful bind. ip_vs_unbind_scheduler() already detects whether a scheduler is installed via svc->scheduler, and keeping sched non-NULL ensures the error path passes the correct pointer to both ip_vs_unbind_scheduler() and ip_vs_scheduler_put(). While the bug is older, the problem popups in more recent kernels (6.2), when the new error path is taken after the ip_vs_start_estimator() call. Fixes: 705dd3444081 ("ipvs: use kthreads for stats estimation") Reported-by: Xiang Mei <xmei5@asu.edu> Signed-off-by: Weiming Shi <bestswngs@gmail.com> Acked-by: Simon Horman <horms@kernel.org> Acked-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 9a91797e61d286805ae10a92cc48959c30800556 ]

When ip_vs_bind_scheduler() succeeds in ip_vs_add_service(), the local
variable sched is set to NULL.  If ip_vs_start_estimator() subsequently
fails, the out_err cleanup calls ip_vs_unbind_scheduler(svc, sched)
with sched == NULL.  ip_vs_unbind_scheduler() passes the cur_sched NULL
check (because svc->scheduler was set by the successful bind) but then
dereferences the NULL sched parameter at sched->done_service, causing a
kernel panic at offset 0x30 from NULL.

 Oops: general protection fault, [..] [#1] PREEMPT SMP KASAN NOPTI
 KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
 RIP: 0010:ip_vs_unbind_scheduler (net/netfilter/ipvs/ip_vs_sched.c:69)
 Call Trace:
  <TASK>
  ip_vs_add_service.isra.0 (net/netfilter/ipvs/ip_vs_ctl.c:1500)
  do_ip_vs_set_ctl (net/netfilter/ipvs/ip_vs_ctl.c:2809)
  nf_setsockopt (net/netfilter/nf_sockopt.c:102)
  [..]

Fix by simply not clearing the local sched variable after a successful
bind.  ip_vs_unbind_scheduler() already detects whether a scheduler is
installed via svc->scheduler, and keeping sched non-NULL ensures the
error path passes the correct pointer to both ip_vs_unbind_scheduler()
and ip_vs_scheduler_put().

While the bug is older, the problem popups in more recent kernels (6.2),
when the new error path is taken after the ip_vs_start_estimator() call.

Fixes: 705dd3444081 ("ipvs: use kthreads for stats estimation")
Reported-by: Xiang Mei <xmei5@asu.edu>
Signed-off-by: Weiming Shi <bestswngs@gmail.com>
Acked-by: Simon Horman <horms@kernel.org>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ipvs: do not keep dest_dst if dev is going down 2026-02-26T22:59:39+00:00 Julian Anastasov ja@ssi.bg 2026-02-14T14:58:50+00:00 bae53b3baf2ff2f45f9205c438818fc055601a54 [ Upstream commit 8fde939b0206afc1d5846217a01a16b9bc8c7896 ] There is race between the netdev notifier ip_vs_dst_event() and the code that caches dst with dev that is going down. As the FIB can be notified for the closed device after our handler finishes, it is possible valid route to be returned and cached resuling in a leaked dev reference until the dest is not removed. To prevent new dest_dst to be attached to dest just after the handler dropped the old one, add a netif_running() check to make sure the notifier handler is not currently running for device that is closing. Fixes: 7a4f0761fce3 ("IPVS: init and cleanup restructuring") Signed-off-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 8fde939b0206afc1d5846217a01a16b9bc8c7896 ]

There is race between the netdev notifier ip_vs_dst_event()
and the code that caches dst with dev that is going down.
As the FIB can be notified for the closed device after our
handler finishes, it is possible valid route to be returned
and cached resuling in a leaked dev reference until the dest
is not removed.

To prevent new dest_dst to be attached to dest just after the
handler dropped the old one, add a netif_running() check
to make sure the notifier handler is not currently running
for device that is closing.

Fixes: 7a4f0761fce3 ("IPVS: init and cleanup restructuring")
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ipvs: fix ipv4 null-ptr-deref in route error path 2026-01-02T11:56:47+00:00 Slavin Liu slavin452@gmail.com 2025-11-21T08:52:13+00:00 689a627d14788ad772e0fa24c2e57a23dbc7ce90 [ Upstream commit ad891bb3d079a46a821bf2b8867854645191bab0 ] The IPv4 code path in __ip_vs_get_out_rt() calls dst_link_failure() without ensuring skb->dev is set, leading to a NULL pointer dereference in fib_compute_spec_dst() when ipv4_link_failure() attempts to send ICMP destination unreachable messages. The issue emerged after commit ed0de45a1008 ("ipv4: recompile ip options in ipv4_link_failure") started calling __ip_options_compile() from ipv4_link_failure(). This code path eventually calls fib_compute_spec_dst() which dereferences skb->dev. An attempt was made to fix the NULL skb->dev dereference in commit 0113d9c9d1cc ("ipv4: fix null-deref in ipv4_link_failure"), but it only addressed the immediate dev_net(skb->dev) dereference by using a fallback device. The fix was incomplete because fib_compute_spec_dst() later in the call chain still accesses skb->dev directly, which remains NULL when IPVS calls dst_link_failure(). The crash occurs when: 1. IPVS processes a packet in NAT mode with a misconfigured destination 2. Route lookup fails in __ip_vs_get_out_rt() before establishing a route 3. The error path calls dst_link_failure(skb) with skb->dev == NULL 4. ipv4_link_failure() → ipv4_send_dest_unreach() → __ip_options_compile() → fib_compute_spec_dst() 5. fib_compute_spec_dst() dereferences NULL skb->dev Apply the same fix used for IPv6 in commit 326bf17ea5d4 ("ipvs: fix ipv6 route unreach panic"): set skb->dev from skb_dst(skb)->dev before calling dst_link_failure(). KASAN: null-ptr-deref in range [0x0000000000000328-0x000000000000032f] CPU: 1 PID: 12732 Comm: syz.1.3469 Not tainted 6.6.114 #2 RIP: 0010:__in_dev_get_rcu include/linux/inetdevice.h:233 RIP: 0010:fib_compute_spec_dst+0x17a/0x9f0 net/ipv4/fib_frontend.c:285 Call Trace: <TASK> spec_dst_fill net/ipv4/ip_options.c:232 spec_dst_fill net/ipv4/ip_options.c:229 __ip_options_compile+0x13a1/0x17d0 net/ipv4/ip_options.c:330 ipv4_send_dest_unreach net/ipv4/route.c:1252 ipv4_link_failure+0x702/0xb80 net/ipv4/route.c:1265 dst_link_failure include/net/dst.h:437 __ip_vs_get_out_rt+0x15fd/0x19e0 net/netfilter/ipvs/ip_vs_xmit.c:412 ip_vs_nat_xmit+0x1d8/0xc80 net/netfilter/ipvs/ip_vs_xmit.c:764 Fixes: ed0de45a1008 ("ipv4: recompile ip options in ipv4_link_failure") Signed-off-by: Slavin Liu <slavin452@gmail.com> Acked-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit ad891bb3d079a46a821bf2b8867854645191bab0 ]

The IPv4 code path in __ip_vs_get_out_rt() calls dst_link_failure()
without ensuring skb->dev is set, leading to a NULL pointer dereference
in fib_compute_spec_dst() when ipv4_link_failure() attempts to send
ICMP destination unreachable messages.

The issue emerged after commit ed0de45a1008 ("ipv4: recompile ip options
in ipv4_link_failure") started calling __ip_options_compile() from
ipv4_link_failure(). This code path eventually calls fib_compute_spec_dst()
which dereferences skb->dev. An attempt was made to fix the NULL skb->dev
dereference in commit 0113d9c9d1cc ("ipv4: fix null-deref in
ipv4_link_failure"), but it only addressed the immediate dev_net(skb->dev)
dereference by using a fallback device. The fix was incomplete because
fib_compute_spec_dst() later in the call chain still accesses skb->dev
directly, which remains NULL when IPVS calls dst_link_failure().

The crash occurs when:
1. IPVS processes a packet in NAT mode with a misconfigured destination
2. Route lookup fails in __ip_vs_get_out_rt() before establishing a route
3. The error path calls dst_link_failure(skb) with skb->dev == NULL
4. ipv4_link_failure() → ipv4_send_dest_unreach() →
   __ip_options_compile() → fib_compute_spec_dst()
5. fib_compute_spec_dst() dereferences NULL skb->dev

Apply the same fix used for IPv6 in commit 326bf17ea5d4 ("ipvs: fix
ipv6 route unreach panic"): set skb->dev from skb_dst(skb)->dev before
calling dst_link_failure().

KASAN: null-ptr-deref in range [0x0000000000000328-0x000000000000032f]
CPU: 1 PID: 12732 Comm: syz.1.3469 Not tainted 6.6.114 #2
RIP: 0010:__in_dev_get_rcu include/linux/inetdevice.h:233
RIP: 0010:fib_compute_spec_dst+0x17a/0x9f0 net/ipv4/fib_frontend.c:285
Call Trace:
  <TASK>
  spec_dst_fill net/ipv4/ip_options.c:232
  spec_dst_fill net/ipv4/ip_options.c:229
  __ip_options_compile+0x13a1/0x17d0 net/ipv4/ip_options.c:330
  ipv4_send_dest_unreach net/ipv4/route.c:1252
  ipv4_link_failure+0x702/0xb80 net/ipv4/route.c:1265
  dst_link_failure include/net/dst.h:437
  __ip_vs_get_out_rt+0x15fd/0x19e0 net/netfilter/ipvs/ip_vs_xmit.c:412
  ip_vs_nat_xmit+0x1d8/0xc80 net/netfilter/ipvs/ip_vs_xmit.c:764

Fixes: ed0de45a1008 ("ipv4: recompile ip options in ipv4_link_failure")
Signed-off-by: Slavin Liu <slavin452@gmail.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ipvs: Defer ip_vs_ftp unregister during netns cleanup 2025-09-24T09:50:28+00:00 Slavin Liu slavin452@gmail.com 2025-09-11T17:57:59+00:00 134121bfd99a06d44ef5ba15a9beb075297c0821 On the netns cleanup path, __ip_vs_ftp_exit() may unregister ip_vs_ftp before connections with valid cp->app pointers are flushed, leading to a use-after-free. Fix this by introducing a global `exiting_module` flag, set to true in ip_vs_ftp_exit() before unregistering the pernet subsystem. In __ip_vs_ftp_exit(), skip ip_vs_ftp unregister if called during netns cleanup (when exiting_module is false) and defer it to __ip_vs_cleanup_batch(), which unregisters all apps after all connections are flushed. If called during module exit, unregister ip_vs_ftp immediately. Fixes: 61b1ab4583e2 ("IPVS: netns, add basic init per netns.") Suggested-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Slavin Liu <slavin452@gmail.com> Signed-off-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Florian Westphal <fw@strlen.de> 
On the netns cleanup path, __ip_vs_ftp_exit() may unregister ip_vs_ftp
before connections with valid cp->app pointers are flushed, leading to a
use-after-free.

Fix this by introducing a global `exiting_module` flag, set to true in
ip_vs_ftp_exit() before unregistering the pernet subsystem. In
__ip_vs_ftp_exit(), skip ip_vs_ftp unregister if called during netns
cleanup (when exiting_module is false) and defer it to
__ip_vs_cleanup_batch(), which unregisters all apps after all connections
are flushed. If called during module exit, unregister ip_vs_ftp
immediately.

Fixes: 61b1ab4583e2 ("IPVS: netns, add basic init per netns.")
Suggested-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Slavin Liu <slavin452@gmail.com>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
ipvs: Use READ_ONCE/WRITE_ONCE for ipvs->enable 2025-09-11T13:40:55+00:00 Zhang Tengfei zhtfdev@gmail.com 2025-09-01T13:46:54+00:00 944b6b216c0387ac3050cd8b773819ae360bfb1c KCSAN reported a data-race on the `ipvs->enable` flag, which is written in the control path and read concurrently from many other contexts. Following a suggestion by Julian, this patch fixes the race by converting all accesses to use `WRITE_ONCE()/READ_ONCE()`. This lightweight approach ensures atomic access and acts as a compiler barrier, preventing unsafe optimizations where the flag is checked in loops (e.g., in ip_vs_est.c). Additionally, the `enable` checks in the fast-path hooks (`ip_vs_in_hook`, `ip_vs_out_hook`, `ip_vs_forward_icmp`) are removed. These are unnecessary since commit 857ca89711de ("ipvs: register hooks only with services"). The `enable=0` condition they check for can only occur in two rare and non-fatal scenarios: 1) after hooks are registered but before the flag is set, and 2) after hooks are unregistered on cleanup_net. In the worst case, a single packet might be mishandled (e.g., dropped), which does not lead to a system crash or data corruption. Adding a check in the performance-critical fast-path to handle this harmless condition is not a worthwhile trade-off. Fixes: 857ca89711de ("ipvs: register hooks only with services") Reported-by: syzbot+1651b5234028c294c339@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=1651b5234028c294c339 Suggested-by: Julian Anastasov <ja@ssi.bg> Link: https://lore.kernel.org/lvs-devel/2189fc62-e51e-78c9-d1de-d35b8e3657e3@ssi.bg/ Signed-off-by: Zhang Tengfei <zhtfdev@gmail.com> Acked-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Florian Westphal <fw@strlen.de> 
KCSAN reported a data-race on the `ipvs->enable` flag, which is
written in the control path and read concurrently from many other
contexts.

Following a suggestion by Julian, this patch fixes the race by
converting all accesses to use `WRITE_ONCE()/READ_ONCE()`.
This lightweight approach ensures atomic access and acts as a
compiler barrier, preventing unsafe optimizations where the flag
is checked in loops (e.g., in ip_vs_est.c).

Additionally, the `enable` checks in the fast-path hooks
(`ip_vs_in_hook`, `ip_vs_out_hook`, `ip_vs_forward_icmp`) are
removed. These are unnecessary since commit 857ca89711de
("ipvs: register hooks only with services"). The `enable=0`
condition they check for can only occur in two rare and non-fatal
scenarios: 1) after hooks are registered but before the flag is set,
and 2) after hooks are unregistered on cleanup_net. In the worst
case, a single packet might be mishandled (e.g., dropped), which
does not lead to a system crash or data corruption. Adding a check
in the performance-critical fast-path to handle this harmless
condition is not a worthwhile trade-off.

Fixes: 857ca89711de ("ipvs: register hooks only with services")
Reported-by: syzbot+1651b5234028c294c339@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=1651b5234028c294c339
Suggested-by: Julian Anastasov <ja@ssi.bg>
Link: https://lore.kernel.org/lvs-devel/2189fc62-e51e-78c9-d1de-d35b8e3657e3@ssi.bg/
Signed-off-by: Zhang Tengfei <zhtfdev@gmail.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
ipvs: Fix estimator kthreads preferred affinity 2025-08-13T06:34:33+00:00 Frederic Weisbecker frederic@kernel.org 2025-07-29T12:26:11+00:00 c0a23bbc98e93704a1f4fb5e7e7bb2d7c0fb6eb3 The estimator kthreads' affinity are defined by sysctl overwritten preferences and applied through a plain call to the scheduler's affinity API. However since the introduction of managed kthreads preferred affinity, such a practice shortcuts the kthreads core code which eventually overwrites the target to the default unbound affinity. Fix this with using the appropriate kthread's API. Fixes: d1a89197589c ("kthread: Default affine kthread to its preferred NUMA node") Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Acked-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Florian Westphal <fw@strlen.de> 
The estimator kthreads' affinity are defined by sysctl overwritten
preferences and applied through a plain call to the scheduler's affinity
API.

However since the introduction of managed kthreads preferred affinity,
such a practice shortcuts the kthreads core code which eventually
overwrites the target to the default unbound affinity.

Fix this with using the appropriate kthread's API.

Fixes: d1a89197589c ("kthread: Default affine kthread to its preferred NUMA node")
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
ipvs: Rename del_timer in comment in ip_vs_conn_expire_now() 2025-07-25T16:39:29+00:00 WangYuli wangyuli@uniontech.com 2025-07-04T08:35:53+00:00 bfabc4f70ee72809f1de662e971ac55648981a31 Commit 8fa7292fee5c ("treewide: Switch/rename to timer_delete[_sync]()") switched del_timer to timer_delete, but did not modify the comment for ip_vs_conn_expire_now(). Now fix it. Signed-off-by: WangYuli <wangyuli@uniontech.com> Acked-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 
Commit 8fa7292fee5c ("treewide: Switch/rename to timer_delete[_sync]()")
switched del_timer to timer_delete, but did not modify the comment for
ip_vs_conn_expire_now(). Now fix it.

Signed-off-by: WangYuli <wangyuli@uniontech.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
net: dst: annotate data-races around dst->obsolete 2025-07-02T21:32:29+00:00 Eric Dumazet edumazet@google.com 2025-06-30T12:19:25+00:00 8a402bbe54760dea67f1b2980c727761b47994d7 (dst_entry)->obsolete is read locklessly, add corresponding annotations. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250630121934.3399505-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
(dst_entry)->obsolete is read locklessly, add corresponding
annotations.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250630121934.3399505-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
treewide, timers: Rename from_timer() to timer_container_of() 2025-06-08T07:07:37+00:00 Ingo Molnar mingo@kernel.org 2025-05-09T05:51:14+00:00 41cb08555c4164996d67c78b3bf1c658075b75f1 Move this API to the canonical timer_*() namespace. [ tglx: Redone against pre rc1 ] Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/aB2X0jCKQO56WdMt@gmail.com 
Move this API to the canonical timer_*() namespace.

[ tglx: Redone against pre rc1 ]

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/aB2X0jCKQO56WdMt@gmail.com
sctp: use skb_crc32c() instead of __skb_checksum() 2025-05-21T22:40:16+00:00 Eric Biggers ebiggers@google.com 2025-05-19T17:50:07+00:00 99de9d4022e5004f95f425f798f0aa01e87949ff Make sctp_compute_cksum() just use the new function skb_crc32c(), instead of calling __skb_checksum() with a skb_checksum_ops struct that does CRC32C. This is faster and simpler. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://patch.msgid.link/20250519175012.36581-6-ebiggers@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Make sctp_compute_cksum() just use the new function skb_crc32c(),
instead of calling __skb_checksum() with a skb_checksum_ops struct that
does CRC32C.  This is faster and simpler.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://patch.msgid.link/20250519175012.36581-6-ebiggers@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>