commit 1d324c2f43 upstream.
After commit 5e72ce3e39 ("net: ipv6: Use link netns in newlink() of
rtnl_link_ops"), ip6erspan_newlink() correctly resolves the per-netns
ip6gre hash via link_net. ip6erspan_changelink() was not converted in
that series and still uses dev_net(dev), which diverges from the
device's creation netns after IFLA_NET_NS_FD migration.
This re-inserts the tunnel into the wrong per-netns hash. The
original netns keeps a stale entry. When that netns is later
destroyed, ip6gre_exit_rtnl_net() walks the stale entry, producing a
slab-use-after-free reported by KASAN, followed by a kernel BUG at
net/core/dev.c (LIST_POISON1) in unregister_netdevice_many_notify().
Reachable from an unprivileged user namespace (unshare --user
--map-root-user --net).
ip6gre_changelink() earlier in the same file already uses the cached
t->net; only ip6erspan_changelink() has the wrong shape.
Fixes: 2d665034f2 ("net: ip6_gre: Fix ip6erspan hlen calculation")
Cc: stable@vger.kernel.org # v5.15+
Signed-off-by: Maoyi Xie <maoyi.xie@ntu.edu.sg>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260430103318.3206018-1-maoyi.xie@ntu.edu.sg
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ec54093e6a upstream.
AH allocates its temporary auth/ICV layout differently when ESN is enabled:
the async ahash setup appends a 4-byte seqhi slot before the ICV or
auth_data area, but the async completion callbacks still reconstruct the
temporary layout as if seqhi were absent.
With an async AH implementation selected, that makes AH copy or compare
the wrong bytes on both the IPv4 and IPv6 paths. In UML repro on IPv4 AH
with ESN and forced async hmac(sha1), ping fails with 100% packet loss,
and the callback logs show the pre-fix drift:
ah4 output_done: esn=1 err=0 icv_off=20 expected_off=24
ah4 input_done: esn=1 auth_off=20 expected_auth_off=24 icv_off=32 expected_icv_off=36
Reconstruct the callback-side layout the same way the setup path built it
by skipping the ESN seqhi slot before locating the saved auth_data or ICV.
Per RFC 4302, the ESN high-order 32 bits participate in the AH ICV
computation, so the async callbacks must account for the seqhi slot.
Post-fix, the same IPv4 AH+ESN+forced-async-hmac(sha1) UML repro shows
the corrected offset (ah4 output_done: esn=1 err=0 icv_off=24
expected_off=24) and ping succeeds; net/ipv4/ah4.o and net/ipv6/ah6.o
build clean at W=1. IPv6 AH+ESN was not exercised at runtime, and the
change has not been tested against a real async hardware AH engine.
Fixes: d4d573d033 ("{IPv4,xfrm} Add ESN support for AH egress part")
Fixes: d8b2a8600b ("{IPv4,xfrm} Add ESN support for AH ingress part")
Fixes: 26dd70c3fa ("{IPv6,xfrm} Add ESN support for AH egress part")
Fixes: 8d6da6f325 ("{IPv6,xfrm} Add ESN support for AH ingress part")
Cc: stable@vger.kernel.org
Assisted-by: Codex:gpt-5-4
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit bc0fcb9823 upstream.
xfrm6_rcv_encap() performs an IPv6 route lookup when the skb does not
already have a dst attached. ip6_route_input_lookup() returns a
referenced dst entry even when the lookup resolves to an error route.
If dst->error is set, xfrm6_rcv_encap() drops the skb without attaching
the dst to the skb and without releasing the reference returned by the
lookup. Repeated packets hitting this path therefore leak dst entries.
Release the dst before jumping to the drop path.
Fixes: 0146dca70b ("xfrm: add support for UDPv6 encapsulation of ESP")
Cc: stable@kernel.org
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Co-developed-by: Yuan Tan <yuantan098@gmail.com>
Signed-off-by: Yuan Tan <yuantan098@gmail.com>
Suggested-by: Xin Liu <bird@lzu.edu.cn>
Tested-by: Ruide Cao <caoruide123@gmail.com>
Signed-off-by: Yilin Zhu <zylzyl2333@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f4c50a4034 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: cac2661c53 ("esp4: Avoid skb_cow_data whenever possible")
Fixes: 03e2a30f6a ("esp6: Avoid skb_cow_data whenever possible")
Fixes: 7da0dde684 ("ip, udp: Support MSG_SPLICE_PAGES")
Fixes: 6d8192bd69 ("ip6, udp6: Support MSG_SPLICE_PAGES")
Reported-by: Hyunwoo Kim <imv4bel@gmail.com>
Reported-by: Kuan-Ting Chen <h3xrabbit@gmail.com>
Tested-by: Hyunwoo Kim <imv4bel@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Kuan-Ting Chen <h3xrabbit@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f9c52a6ba9 upstream.
seg6_input_core() and rpl_input() call ip6_route_input() which sets a
NOREF dst on the skb, then pass it to dst_cache_set_ip6() invoking
dst_hold() unconditionally.
On PREEMPT_RT, ksoftirqd is preemptible and a higher-priority task can
release the underlying pcpu_rt between the lookup and the caching
through a concurrent FIB lookup on a shared nexthop.
Simplified race sequence:
ksoftirqd/X higher-prio task (same CPU X)
----------- --------------------------------
seg6_input_core(,skb)/rpl_input(skb)
dst_cache_get()
-> miss
ip6_route_input(skb)
-> ip6_pol_route(,skb,flags)
[RT6_LOOKUP_F_DST_NOREF in flags]
-> FIB lookup resolves fib6_nh
[nhid=N route]
-> rt6_make_pcpu_route()
[creates pcpu_rt, refcount=1]
pcpu_rt->sernum = fib6_sernum
[fib6_sernum=W]
-> cmpxchg(fib6_nh.rt6i_pcpu,
NULL, pcpu_rt)
[slot was empty, store succeeds]
-> skb_dst_set_noref(skb, dst)
[dst is pcpu_rt, refcount still 1]
rt_genid_bump_ipv6()
-> bumps fib6_sernum
[fib6_sernum from W to Z]
ip6_route_output()
-> ip6_pol_route()
-> FIB lookup resolves fib6_nh
[nhid=N]
-> rt6_get_pcpu_route()
pcpu_rt->sernum != fib6_sernum
[W <> Z, stale]
-> prev = xchg(rt6i_pcpu, NULL)
-> dst_release(prev)
[prev is pcpu_rt,
refcount 1->0, dead]
dst = skb_dst(skb)
[dst is the dead pcpu_rt]
dst_cache_set_ip6(dst)
-> dst_hold() on dead dst
-> WARN / use-after-free
For the race to occur, ksoftirqd must be preemptible (PREEMPT_RT without
PREEMPT_RT_NEEDS_BH_LOCK) and a concurrent task must be able to release
the pcpu_rt. Shared nexthop objects provide such a path, as two routes
pointing to the same nhid share the same fib6_nh and its rt6i_pcpu
entry.
Fix seg6_input_core() and rpl_input() by calling skb_dst_force() after
ip6_route_input() to force the NOREF dst into a refcounted one before
caching.
The output path is not affected as ip6_route_output() already returns a
refcounted dst.
Fixes: af4a2209b1 ("ipv6: sr: use dst_cache in seg6_input")
Fixes: a7a29f9c36 ("net: ipv6: add rpl sr tunnel")
Cc: stable@vger.kernel.org
Signed-off-by: Andrea Mayer <andrea.mayer@uniroma2.it>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Justin Iurman <justin.iurman@gmail.com>
Link: https://patch.msgid.link/20260421094735.20997-1-andrea.mayer@uniroma2.it
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9e6bf146b5 upstream.
ipv6_rpl_srh_rcv() decompresses an RFC 6554 Source Routing Header, swaps
the next segment into ipv6_hdr->daddr, recompresses, then pulls the old
header and pushes the new one plus the IPv6 header back. The
recompressed header can be larger than the received one when the swap
reduces the common-prefix length the segments share with daddr (CmprI=0,
CmprE>0, seg[0][0] != daddr[0] gives the maximum +8 bytes).
pskb_expand_head() was gated on segments_left == 0, so on earlier
segments the push consumed unchecked headroom. Once skb_push() leaves
fewer than skb->mac_len bytes in front of data,
skb_mac_header_rebuild()'s call to:
skb_set_mac_header(skb, -skb->mac_len);
will store (data - head) - mac_len into the u16 mac_header field, which
wraps to ~65530, and the following memmove() writes mac_len bytes ~64KiB
past skb->head.
A single AF_INET6/SOCK_RAW/IPV6_HDRINCL packet over lo with a two
segment type-3 SRH (CmprI=0, CmprE=15) reaches headroom 8 after one
pass; KASAN reports a 14-byte OOB write in ipv6_rthdr_rcv.
Fix this by expanding the head whenever the remaining room is less than
the push size plus mac_len, and request that much extra so the rebuilt
MAC header fits afterwards.
Fixes: 8610c7c6e3 ("net: ipv6: add support for rpl sr exthdr")
Cc: stable <stable@kernel.org>
Reported-by: Anthropic
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/2026042133-gout-unvented-1bd9@gregkh
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ade67d5f58 upstream.
When SEG6_IPTUN_MODE_L2ENCAP_RED (L2ENCAP_RED) was introduced, the
condition in seg6_build_state() that excludes L2 encap modes from
setting LWTUNNEL_STATE_OUTPUT_REDIRECT was not updated to account for
the new mode.
As a consequence, L2ENCAP_RED routes incorrectly trigger seg6_output()
on the output path, where the packet is silently dropped because
skb_mac_header_was_set() fails on L3 packets.
Extend the check to also exclude L2ENCAP_RED, consistent with L2ENCAP.
Fixes: 13f0296be8 ("seg6: add support for SRv6 H.L2Encaps.Red behavior")
Cc: stable@vger.kernel.org
Signed-off-by: Andrea Mayer <andrea.mayer@uniroma2.it>
Reviewed-by: Justin Iurman <justin.iurman@gmail.com>
Link: https://patch.msgid.link/20260418162838.31979-1-andrea.mayer@uniroma2.it
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 0641379352 ]
__in6_dev_get() can return NULL when the device has no IPv6 configuration
(e.g. MTU < IPV6_MIN_MTU or after NETDEV_UNREGISTER).
Add NULL checks for idev returned by __in6_dev_get() in both
seg6_hmac_validate_skb() and ipv6_srh_rcv() to prevent potential NULL
pointer dereferences.
Fixes: 1ababeba4a ("ipv6: implement dataplane support for rthdr type 4 (Segment Routing Header)")
Fixes: bf355b8d2c ("ipv6: sr: add core files for SR HMAC support")
Signed-off-by: Minhong He <heminhong@kylinos.cn>
Reviewed-by: Andrea Mayer <andrea.mayer@uniroma2.it>
Link: https://patch.msgid.link/20260316073301.106643-1-heminhong@kylinos.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Li hongliang <1468888505@139.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit fdce0b3590 ]
`eui64_mt6()` derives a modified EUI-64 from the Ethernet source address
and compares it with the low 64 bits of the IPv6 source address.
The existing guard only rejects an invalid MAC header when
`par->fragoff != 0`. For packets with `par->fragoff == 0`, `eui64_mt6()`
can still reach `eth_hdr(skb)` even when the MAC header is not valid.
Fix this by removing the `par->fragoff != 0` condition so that packets
with an invalid MAC header are rejected before accessing `eth_hdr(skb)`.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Co-developed-by: Yuan Tan <yuantan098@gmail.com>
Signed-off-by: Yuan Tan <yuantan098@gmail.com>
Suggested-by: Xin Liu <bird@lzu.edu.cn>
Tested-by: Ren Wei <enjou1224z@gmail.com>
Signed-off-by: Zhengchuan Liang <zcliangcn@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit c3812651b5 upstream.
The seg6 lwtunnel uses a single dst_cache per encap route, shared
between seg6_input_core() and seg6_output_core(). These two paths
can perform the post-encap SID lookup in different routing contexts
(e.g., ip rules matching on the ingress interface, or VRF table
separation). Whichever path runs first populates the cache, and the
other reuses it blindly, bypassing its own lookup.
Fix this by splitting the cache into cache_input and cache_output,
so each path maintains its own cached dst independently.
Fixes: 6c8702c60b ("ipv6: sr: add support for SRH encapsulation and injection with lwtunnels")
Cc: stable@vger.kernel.org
Signed-off-by: Andrea Mayer <andrea.mayer@uniroma2.it>
Reviewed-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: Justin Iurman <justin.iurman@gmail.com>
Link: https://patch.msgid.link/20260404004405.4057-2-andrea.mayer@uniroma2.it
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 4e45337556 ]
Yiming Qian reported :
<quote>
I believe I found a locally triggerable kernel bug in the IPv6 sendmsg
ancillary-data path that can panic the kernel via `skb_under_panic()`
(local DoS).
The core issue is a mismatch between:
- a 16-bit length accumulator (`struct ipv6_txoptions::opt_flen`, type
`__u16`) and
- a pointer to the *last* provided destination-options header (`opt->dst1opt`)
when multiple `IPV6_DSTOPTS` control messages (cmsgs) are provided.
- `include/net/ipv6.h`:
- `struct ipv6_txoptions::opt_flen` is `__u16` (wrap possible).
(lines 291-307, especially 298)
- `net/ipv6/datagram.c:ip6_datagram_send_ctl()`:
- Accepts repeated `IPV6_DSTOPTS` and accumulates into `opt_flen`
without rejecting duplicates. (lines 909-933)
- `net/ipv6/ip6_output.c:__ip6_append_data()`:
- Uses `opt->opt_flen + opt->opt_nflen` to compute header
sizes/headroom decisions. (lines 1448-1466, especially 1463-1465)
- `net/ipv6/ip6_output.c:__ip6_make_skb()`:
- Calls `ipv6_push_frag_opts()` if `opt->opt_flen` is non-zero.
(lines 1930-1934)
- `net/ipv6/exthdrs.c:ipv6_push_frag_opts()` / `ipv6_push_exthdr()`:
- Push size comes from `ipv6_optlen(opt->dst1opt)` (based on the
pointed-to header). (lines 1179-1185 and 1206-1211)
1. `opt_flen` is a 16-bit accumulator:
- `include/net/ipv6.h:298` defines `__u16 opt_flen; /* after fragment hdr */`.
2. `ip6_datagram_send_ctl()` accepts *repeated* `IPV6_DSTOPTS` cmsgs
and increments `opt_flen` each time:
- In `net/ipv6/datagram.c:909-933`, for `IPV6_DSTOPTS`:
- It computes `len = ((hdr->hdrlen + 1) << 3);`
- It checks `CAP_NET_RAW` using `ns_capable(net->user_ns,
CAP_NET_RAW)`. (line 922)
- Then it does:
- `opt->opt_flen += len;` (line 927)
- `opt->dst1opt = hdr;` (line 928)
There is no duplicate rejection here (unlike the legacy
`IPV6_2292DSTOPTS` path which rejects duplicates at
`net/ipv6/datagram.c:901-904`).
If enough large `IPV6_DSTOPTS` cmsgs are provided, `opt_flen` wraps
while `dst1opt` still points to a large (2048-byte)
destination-options header.
In the attached PoC (`poc.c`):
- 32 cmsgs with `hdrlen=255` => `len = (255+1)*8 = 2048`
- 1 cmsg with `hdrlen=0` => `len = 8`
- Total increment: `32*2048 + 8 = 65544`, so `(__u16)opt_flen == 8`
- The last cmsg is 2048 bytes, so `dst1opt` points to a 2048-byte header.
3. The transmit path sizes headers using the wrapped `opt_flen`:
- In `net/ipv6/ip6_output.c:1463-1465`:
- `headersize = sizeof(struct ipv6hdr) + (opt ? opt->opt_flen +
opt->opt_nflen : 0) + ...;`
With wrapped `opt_flen`, `headersize`/headroom decisions underestimate
what will be pushed later.
4. When building the final skb, the actual push length comes from
`dst1opt` and is not limited by wrapped `opt_flen`:
- In `net/ipv6/ip6_output.c:1930-1934`:
- `if (opt->opt_flen) proto = ipv6_push_frag_opts(skb, opt, proto);`
- In `net/ipv6/exthdrs.c:1206-1211`, `ipv6_push_frag_opts()` pushes
`dst1opt` via `ipv6_push_exthdr()`.
- In `net/ipv6/exthdrs.c:1179-1184`, `ipv6_push_exthdr()` does:
- `skb_push(skb, ipv6_optlen(opt));`
- `memcpy(h, opt, ipv6_optlen(opt));`
With insufficient headroom, `skb_push()` underflows and triggers
`skb_under_panic()` -> `BUG()`:
- `net/core/skbuff.c:2669-2675` (`skb_push()` calls `skb_under_panic()`)
- `net/core/skbuff.c:207-214` (`skb_panic()` ends in `BUG()`)
- The `IPV6_DSTOPTS` cmsg path requires `CAP_NET_RAW` in the target
netns user namespace (`ns_capable(net->user_ns, CAP_NET_RAW)`).
- Root (or any task with `CAP_NET_RAW`) can trigger this without user
namespaces.
- An unprivileged `uid=1000` user can trigger this if unprivileged
user namespaces are enabled and it can create a userns+netns to obtain
namespaced `CAP_NET_RAW` (the attached PoC does this).
- Local denial of service: kernel BUG/panic (system crash).
- Reproducible with a small userspace PoC.
</quote>
This patch does not reject duplicated options, as this might break
some user applications.
Instead, it makes sure to adjust opt_flen and opt_nflen to correctly
reflect the size of the current option headers, preventing the overflows
and the potential for panics.
This applies to IPV6_DSTOPTS, IPV6_HOPOPTS, and IPV6_RTHDR.
Specifically:
When a new IPV6_DSTOPTS is processed, the length of the old opt->dst1opt
is subtracted from opt->opt_flen before adding the new length.
When a new IPV6_HOPOPTS is processed, the length of the old opt->dst0opt
is subtracted from opt->opt_nflen.
When a new Routing Header (IPV6_RTHDR or IPV6_2292RTHDR) is processed,
the length of the old opt->srcrt is subtracted from opt->opt_nflen.
In the special case within IPV6_2292RTHDR handling where dst1opt is moved
to dst0opt, the length of the old opt->dst0opt is subtracted from
opt->opt_nflen before the new one is added.
Fixes: 333fad5364 ("[IPV6]: Support several new sockopt / ancillary data in Advanced API (RFC3542).")
Reported-by: Yiming Qian <yimingqian591@gmail.com>
Closes: https://lore.kernel.org/netdev/CAL_bE8JNzawgr5OX5m+3jnQDHry2XxhQT5=jThW1zDPtUikRYA@mail.gmail.com/
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260401154721.3740056-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 9ca562bb8e ]
`ip6fl_seq_show()` walks the global flowlabel hash under the seq-file
RCU read-side lock and prints `fl->opt->opt_nflen` when an option block
is present.
Exclusive flowlabels currently free `fl->opt` as soon as `fl->users`
drops to zero in `fl_release()`. However, the surrounding
`struct ip6_flowlabel` remains visible in the global hash table until
later garbage collection removes it and `fl_free_rcu()` finally tears it
down.
A concurrent `/proc/net/ip6_flowlabel` reader can therefore race that
early `kfree()` and dereference freed option state, triggering a crash
in `ip6fl_seq_show()`.
Fix this by keeping `fl->opt` alive until `fl_free_rcu()`. That matches
the lifetime already required for the enclosing flowlabel while readers
can still reach it under RCU.
Fixes: d3aedd5ebd ("ipv6 flowlabel: Convert hash list to RCU.")
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Co-developed-by: Yuan Tan <yuantan098@gmail.com>
Signed-off-by: Yuan Tan <yuantan098@gmail.com>
Suggested-by: Xin Liu <bird@lzu.edu.cn>
Tested-by: Ren Wei <enjou1224z@gmail.com>
Signed-off-by: Zhengchuan Liang <zcliangcn@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/07351f0ec47bcee289576f39f9354f4a64add6e4.1774855883.git.zcliangcn@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2edfa31769 ]
Oskar Kjos reported the following problem.
ip4ip6_err() calls icmp_send() on a cloned skb whose cb[] was written
by the IPv6 receive path as struct inet6_skb_parm. icmp_send() passes
IPCB(skb2) to __ip_options_echo(), which interprets that cb[] region
as struct inet_skb_parm (IPv4). The layouts differ: inet6_skb_parm.nhoff
at offset 14 overlaps inet_skb_parm.opt.rr, producing a non-zero rr
value. __ip_options_echo() then reads optlen from attacker-controlled
packet data at sptr[rr+1] and copies that many bytes into dopt->__data,
a fixed 40-byte stack buffer (IP_OPTIONS_DATA_FIXED_SIZE).
To fix this we clear skb2->cb[], as suggested by Oskar Kjos.
Also add minimal IPv4 header validation (version == 4, ihl >= 5).
Fixes: c4d3efafcc ("[IPV6] IP6TUNNEL: Add support to IPv4 over IPv6 tunnel.")
Reported-by: Oskar Kjos <oskar.kjos@hotmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260326155138.2429480-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 86ab3e5567 ]
Sashiko AI-review observed:
In ip6_err_gen_icmpv6_unreach(), the skb is an outer IPv4 ICMP error packet
where its cb contains an IPv4 inet_skb_parm. When skb is cloned into skb2
and passed to icmp6_send(), it uses IP6CB(skb2).
IP6CB interprets the IPv4 inet_skb_parm as an inet6_skb_parm. The cipso
offset in inet_skb_parm.opt directly overlaps with dsthao in inet6_skb_parm
at offset 18.
If an attacker sends a forged ICMPv4 error with a CIPSO IP option, dsthao
would be a non-zero offset. Inside icmp6_send(), mip6_addr_swap() is called
and uses ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO).
This would scan the inner, attacker-controlled IPv6 packet starting at that
offset, potentially returning a fake TLV without checking if the remaining
packet length can hold the full 18-byte struct ipv6_destopt_hao.
Could mip6_addr_swap() then perform a 16-byte swap that extends past the end
of the packet data into skb_shared_info?
Should the cb array also be cleared in ip6_err_gen_icmpv6_unreach() and
ip6ip6_err() to prevent this?
This patch implements the first suggestion.
I am not sure if ip6ip6_err() needs to be changed.
A separate patch would be better anyway.
Fixes: ca15a078bd ("sit: generate icmpv6 error when receiving icmpv4 error")
Reported-by: Ido Schimmel <idosch@nvidia.com>
Closes: https://sashiko.dev/#/patchset/20260326155138.2429480-1-edumazet%40google.com
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Oskar Kjos <oskar.kjos@hotmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260326202608.2976021-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 5e67ba9bb5 ]
ioam6_fill_trace_data() stores the schema contribution to the trace
length in a u8. With bit 22 enabled and the largest schema payload,
sclen becomes 1 + 1020 / 4, wraps from 256 to 0, and bypasses the
remaining-space check. __ioam6_fill_trace_data() then positions the
write cursor without reserving the schema area but still copies the
4-byte schema header and the full schema payload, overrunning the trace
buffer.
Keep sclen in an unsigned int so the remaining-space check and the write
cursor calculation both see the full schema length.
Fixes: 8c6f6fa677 ("ipv6: ioam: IOAM Generic Netlink API")
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Reviewed-by: Justin Iurman <justin.iurman@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit ae05340cca ]
When processing Router Advertisements with user options the kernel
builds an RTM_NEWNDUSEROPT netlink message. The nduseroptmsg struct
has three padding fields that are never zeroed and can leak kernel data
The fix is simple, just zeroes the padding fields.
Fixes: 31910575a9 ("[IPv6]: Export userland ND options through netlink (RDNSS support)")
Signed-off-by: Yochai Eisenrich <echelonh@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260324224925.2437775-1-echelonh@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 4be7b99c25 ]
The cited commit mechanically put fib6_remove_gc_list()
just after every fib6_clean_expires() call.
When a temporary route is promoted to a permanent route,
there may already be exception routes tied to it.
If fib6_remove_gc_list() removes the route from tb6_gc_hlist,
such exception routes will no longer be aged.
Let's replace fib6_remove_gc_list() with a new helper
fib6_may_remove_gc_list() and use fib6_age_exceptions() there.
Note that net->ipv6 is only compiled when CONFIG_IPV6 is
enabled, so fib6_{add,remove,may_remove}_gc_list() are guarded.
Fixes: 5eb902b8e7 ("net/ipv6: Remove expired routes with a separated list of routes.")
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20260320072317.2561779-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 6af51e9f31 ]
Commit 5eb902b8e7 ("net/ipv6: Remove expired routes with a
separated list of routes.") introduced a per-table GC list and
changed GC to iterate over that list instead of traversing
the entire route table.
However, it forgot to add permanent routes to tb6_gc_hlist
when exception routes are added.
Commit cfe82469a0 ("ipv6: add exception routes to GC list
in rt6_insert_exception") fixed that issue but introduced
another one.
Even after all exception routes expire, the permanent routes
remain in tb6_gc_hlist, potentially negating the performance
benefits intended by the initial change.
Let's count gc_args->more before and after rt6_age_exceptions()
and remove the permanent route when the delta is 0.
Note that the next patch will reuse fib6_age_exceptions().
Fixes: cfe82469a0 ("ipv6: add exception routes to GC list in rt6_insert_exception")
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20260320072317.2561779-2-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 0c0eef8ccd ]
When the TX queue for espintcp is full, esp_output_tail_tcp will
return an error and not free the skb, because with synchronous crypto,
the common xfrm output code will drop the packet for us.
With async crypto (esp_output_done), we need to drop the skb when
esp_output_tail_tcp returns an error.
Fixes: e27cca96cd ("xfrm: add espintcp (RFC 8229)")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1620c88887 ]
xfrm assumed to always have a full socket at skb->sk.
This is not always true, so fix it by converting to a
full socket before it is used.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Stable-dep-of: 0c0eef8ccd ("esp: fix skb leak with espintcp and async crypto")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 21ec92774d ]
When a standalone IPv6 nexthop object is created with a loopback device
(e.g., "ip -6 nexthop add id 100 dev lo"), fib6_nh_init() misclassifies
it as a reject route. This is because nexthop objects have no destination
prefix (fc_dst=::), causing fib6_is_reject() to match any loopback
nexthop. The reject path skips fib_nh_common_init(), leaving
nhc_pcpu_rth_output unallocated. If an IPv4 route later references this
nexthop, __mkroute_output() dereferences NULL nhc_pcpu_rth_output and
panics.
Simplify the check in fib6_nh_init() to only match explicit reject
routes (RTF_REJECT) instead of using fib6_is_reject(). The loopback
promotion heuristic in fib6_is_reject() is handled separately by
ip6_route_info_create_nh(). After this change, the three cases behave
as follows:
1. Explicit reject route ("ip -6 route add unreachable 2001:db8::/64"):
RTF_REJECT is set, enters reject path, skips fib_nh_common_init().
No behavior change.
2. Implicit loopback reject route ("ip -6 route add 2001:db8::/32 dev lo"):
RTF_REJECT is not set, takes normal path, fib_nh_common_init() is
called. ip6_route_info_create_nh() still promotes it to reject
afterward. nhc_pcpu_rth_output is allocated but unused, which is
harmless.
3. Standalone nexthop object ("ip -6 nexthop add id 100 dev lo"):
RTF_REJECT is not set, takes normal path, fib_nh_common_init() is
called. nhc_pcpu_rth_output is properly allocated, fixing the crash
when IPv4 routes reference this nexthop.
Suggested-by: Ido Schimmel <idosch@nvidia.com>
Fixes: 493ced1ac4 ("ipv4: Allow routes to use nexthop objects")
Reported-by: syzbot+334190e097a98a1b81bb@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/698f8482.a70a0220.2c38d7.00ca.GAE@google.com/T/
Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20260304113817.294966-2-jiayuan.chen@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2ffb4f5c2c ]
l3mdev_master_dev_rcu() can return NULL when the slave device is being
un-slaved from a VRF. All other callers deal with this, but we lost
the fallback to loopback in ip6_rt_pcpu_alloc() -> ip6_rt_get_dev_rcu()
with commit 4832c30d54 ("net: ipv6: put host and anycast routes on
device with address").
KASAN: null-ptr-deref in range [0x0000000000000108-0x000000000000010f]
RIP: 0010:ip6_rt_pcpu_alloc (net/ipv6/route.c:1418)
Call Trace:
ip6_pol_route (net/ipv6/route.c:2318)
fib6_rule_lookup (net/ipv6/fib6_rules.c:115)
ip6_route_output_flags (net/ipv6/route.c:2607)
vrf_process_v6_outbound (drivers/net/vrf.c:437)
I was tempted to rework the un-slaving code to clear the flag first
and insert synchronize_rcu() before we remove the upper. But looks like
the explicit fallback to loopback_dev is an established pattern.
And I guess avoiding the synchronize_rcu() is nice, too.
Fixes: 4832c30d54 ("net: ipv6: put host and anycast routes on device with address")
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20260301194548.927324-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 6db8b56eed ]
On the receive path, __ioam6_fill_trace_data() uses trace->nodelen
to decide how much data to write for each node. It trusts this field
as-is from the incoming packet, with no consistency check against
trace->type (the 24-bit field that tells which data items are
present). A crafted packet can set nodelen=0 while setting type bits
0-21, causing the function to write ~100 bytes past the allocated
region (into skb_shared_info), which corrupts adjacent heap memory
and leads to a kernel panic.
Add a shared helper ioam6_trace_compute_nodelen() in ioam6.c to
derive the expected nodelen from the type field, and use it:
- in ioam6_iptunnel.c (send path, existing validation) to replace
the open-coded computation;
- in exthdrs.c (receive path, ipv6_hop_ioam) to drop packets whose
nodelen is inconsistent with the type field, before any data is
written.
Per RFC 9197, bits 12-21 are each short (4-octet) fields, so they
are included in IOAM6_MASK_SHORT_FIELDS (changed from 0xff100000 to
0xff1ffc00).
Fixes: 9ee11f0fff ("ipv6: ioam: Data plane support for Pre-allocated Trace")
Cc: stable@vger.kernel.org
Signed-off-by: Junxi Qian <qjx1298677004@gmail.com>
Reviewed-by: Justin Iurman <justin.iurman@gmail.com>
Link: https://patch.msgid.link/20260211040412.86195-1-qjx1298677004@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1799d8abea ]
xfrm6_get_saddr() does not check the return value of
ipv6_dev_get_saddr(). When ipv6_dev_get_saddr() fails to find a suitable
source address (returns -EADDRNOTAVAIL), saddr->in6 is left
uninitialized, but xfrm6_get_saddr() still returns 0 (success).
This causes the caller xfrm_tmpl_resolve_one() to use the uninitialized
address in xfrm_state_find(), triggering KMSAN warning:
=====================================================
BUG: KMSAN: uninit-value in xfrm_state_find+0x2424/0xa940
xfrm_state_find+0x2424/0xa940
xfrm_resolve_and_create_bundle+0x906/0x5a20
xfrm_lookup_with_ifid+0xcc0/0x3770
xfrm_lookup_route+0x63/0x2b0
ip_route_output_flow+0x1ce/0x270
udp_sendmsg+0x2ce1/0x3400
inet_sendmsg+0x1ef/0x2a0
__sock_sendmsg+0x278/0x3d0
__sys_sendto+0x593/0x720
__x64_sys_sendto+0x130/0x200
x64_sys_call+0x332b/0x3e70
do_syscall_64+0xd3/0xf80
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Local variable tmp.i.i created at:
xfrm_resolve_and_create_bundle+0x3e3/0x5a20
xfrm_lookup_with_ifid+0xcc0/0x3770
=====================================================
Fix by checking the return value of ipv6_dev_get_saddr() and propagating
the error.
Fixes: a1e59abf82 ("[XFRM]: Fix wildcard as tunnel source")
Reported-by: syzbot+e136d86d34b42399a8b1@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68bf1024.a70a0220.7a912.02c2.GAE@google.com/T/
Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com>
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c89477ad79 ]
Yizhou Zhao reported that simply having one RAW socket on protocol
IPPROTO_RAW (255) was dangerous.
socket(AF_INET, SOCK_RAW, 255);
A malicious incoming ICMP packet can set the protocol field to 255
and match this socket, leading to FNHE cache changes.
inner = IP(src="192.168.2.1", dst="8.8.8.8", proto=255)/Raw("TEST")
pkt = IP(src="192.168.1.1", dst="192.168.2.1")/ICMP(type=3, code=4, nexthopmtu=576)/inner
"man 7 raw" states:
A protocol of IPPROTO_RAW implies enabled IP_HDRINCL and is able
to send any IP protocol that is specified in the passed header.
Receiving of all IP protocols via IPPROTO_RAW is not possible
using raw sockets.
Make sure we drop these malicious packets.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Link: https://lore.kernel.org/netdev/20251109134600.292125-1-zhaoyz24@mails.tsinghua.edu.cn/
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260203192509.682208-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit bbf4a17ad9 ]
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c5 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling->fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
<TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Fixes: f72514b3c5 ("ipv6: clear RA flags when adding a static route")
Reported-by: syzbot+cb809def1baaac68ab92@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=cb809def1baaac68ab92
Tested-by: syzbot+cb809def1baaac68ab92@syzkaller.appspotmail.com
Signed-off-by: Shigeru Yoshida <syoshida@redhat.com>
Reviewed-by: Fernando Fernandez Mancera <fmancera@suse.de>
Link: https://patch.msgid.link/20260204095837.1285552-1-syoshida@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 426ca15c7f upstream.
This patch enhances GSO segment handling by properly checking
the SKB_GSO_DODGY flag for frag_list GSO packets, addressing
low throughput issues observed when a station accesses IPv4
servers via hotspots with an IPv6-only upstream interface.
Specifically, it fixes a bug in GSO segmentation when forwarding
GRO packets containing a frag_list. The function skb_segment_list
cannot correctly process GRO skbs that have been converted by XLAT,
since XLAT only translates the header of the head skb. Consequently,
skbs in the frag_list may remain untranslated, resulting in protocol
inconsistencies and reduced throughput.
To address this, the patch explicitly sets the SKB_GSO_DODGY flag
for GSO packets in XLAT's IPv4/IPv6 protocol translation helpers
(bpf_skb_proto_4_to_6 and bpf_skb_proto_6_to_4). This marks GSO
packets as potentially modified after protocol translation. As a
result, GSO segmentation will avoid using skb_segment_list and
instead falls back to skb_segment for packets with the SKB_GSO_DODGY
flag. This ensures that only safe and fully translated frag_list
packets are processed by skb_segment_list, resolving protocol
inconsistencies and improving throughput when forwarding GRO packets
converted by XLAT.
Signed-off-by: Jibin Zhang <jibin.zhang@mediatek.com>
Fixes: 9fd1ff5d2a ("udp: Support UDP fraglist GRO/GSO.")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260126152114.1211-1-jibin.zhang@mediatek.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 03cbcdf938 ]
When replying to a ICMPv6 echo request that comes from localhost address
the right output ifindex is 1 (lo) and not rt6i_idev dev index. Use the
skb device ifindex instead. This fixes pinging to a local address from
localhost source address.
$ ping6 -I ::1 2001:1:1::2 -c 3
PING 2001:1:1::2 (2001:1:1::2) from ::1 : 56 data bytes
64 bytes from 2001:1:1::2: icmp_seq=1 ttl=64 time=0.037 ms
64 bytes from 2001:1:1::2: icmp_seq=2 ttl=64 time=0.069 ms
64 bytes from 2001:1:1::2: icmp_seq=3 ttl=64 time=0.122 ms
2001:1:1::2 ping statistics
3 packets transmitted, 3 received, 0% packet loss, time 2032ms
rtt min/avg/max/mdev = 0.037/0.076/0.122/0.035 ms
Fixes: 1b70d792cf ("ipv6: Use rt6i_idev index for echo replies to a local address")
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20260121194409.6749-1-fmancera@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 9a063f96d8 ]
syzbot found that ndisc_router_discovery() could read and write
in6_dev->ra_mtu without holding a lock [1]
This looks fine, IFLA_INET6_RA_MTU is best effort.
Add READ_ONCE()/WRITE_ONCE() to document the race.
Note that we might also reject illegal MTU values
(mtu < IPV6_MIN_MTU || mtu > skb->dev->mtu) in a future patch.
[1]
BUG: KCSAN: data-race in ndisc_router_discovery / ndisc_router_discovery
read to 0xffff888119809c20 of 4 bytes by task 25817 on cpu 1:
ndisc_router_discovery+0x151d/0x1c90 net/ipv6/ndisc.c:1558
ndisc_rcv+0x2ad/0x3d0 net/ipv6/ndisc.c:1841
icmpv6_rcv+0xe5a/0x12f0 net/ipv6/icmp.c:989
ip6_protocol_deliver_rcu+0xb2a/0x10d0 net/ipv6/ip6_input.c:438
ip6_input_finish+0xf0/0x1d0 net/ipv6/ip6_input.c:489
NF_HOOK include/linux/netfilter.h:318 [inline]
ip6_input+0x5e/0x140 net/ipv6/ip6_input.c:500
ip6_mc_input+0x27c/0x470 net/ipv6/ip6_input.c:590
dst_input include/net/dst.h:474 [inline]
ip6_rcv_finish+0x336/0x340 net/ipv6/ip6_input.c:79
...
write to 0xffff888119809c20 of 4 bytes by task 25816 on cpu 0:
ndisc_router_discovery+0x155a/0x1c90 net/ipv6/ndisc.c:1559
ndisc_rcv+0x2ad/0x3d0 net/ipv6/ndisc.c:1841
icmpv6_rcv+0xe5a/0x12f0 net/ipv6/icmp.c:989
ip6_protocol_deliver_rcu+0xb2a/0x10d0 net/ipv6/ip6_input.c:438
ip6_input_finish+0xf0/0x1d0 net/ipv6/ip6_input.c:489
NF_HOOK include/linux/netfilter.h:318 [inline]
ip6_input+0x5e/0x140 net/ipv6/ip6_input.c:500
ip6_mc_input+0x27c/0x470 net/ipv6/ip6_input.c:590
dst_input include/net/dst.h:474 [inline]
ip6_rcv_finish+0x336/0x340 net/ipv6/ip6_input.c:79
...
value changed: 0x00000000 -> 0xe5400659
Fixes: 49b99da2c9 ("ipv6: add IFLA_INET6_RA_MTU to expose mtu value")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Rocco Yue <rocco.yue@mediatek.com>
Link: https://patch.msgid.link/20260118152941.2563857-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 3d5221af9c ]
Commit 61fafbee6c ("xfrm: Determine inner GSO type from packet inner
protocol") attempted to fix GSO segmentation by reading the inner
protocol from XFRM_MODE_SKB_CB(skb)->protocol. This was incorrect
because the field holds the inner L4 protocol (TCP/UDP) instead of the
required tunnel protocol. Also, the memory location (shared by
XFRM_SKB_CB(skb) which could be overwritten by xfrm_replay_overflow())
is prone to corruption. This combination caused the kernel to select
the wrong inner mode and get the wrong address family.
The correct value is in xfrm_offload(skb)->proto, which is set from
the outer tunnel header's protocol field by esp[4|6]_gso_encap(). It
is initialized by xfrm[4|6]_tunnel_encap_add() to either IPPROTO_IPIP
or IPPROTO_IPV6, using xfrm_af2proto() and correctly reflects the
inner packet's address family.
Fixes: 61fafbee6c ("xfrm: Determine inner GSO type from packet inner protocol")
Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 58fc7342b5 ]
There exists a kernel oops caused by a BUG_ON(nhead < 0) at
net/core/skbuff.c:2232 in pskb_expand_head().
This bug is triggered as part of the calipso_skbuff_setattr()
routine when skb_cow() is passed headroom > INT_MAX
(i.e. (int)(skb_headroom(skb) + len_delta) < 0).
The root cause of the bug is due to an implicit integer cast in
__skb_cow(). The check (headroom > skb_headroom(skb)) is meant to ensure
that delta = headroom - skb_headroom(skb) is never negative, otherwise
we will trigger a BUG_ON in pskb_expand_head(). However, if
headroom > INT_MAX and delta <= -NET_SKB_PAD, the check passes, delta
becomes negative, and pskb_expand_head() is passed a negative value for
nhead.
Fix the trigger condition in calipso_skbuff_setattr(). Avoid passing
"negative" headroom sizes to skb_cow() within calipso_skbuff_setattr()
by only using skb_cow() to grow headroom.
PoC:
Using `netlabelctl` tool:
netlabelctl map del default
netlabelctl calipso add pass doi:7
netlabelctl map add default address:0::1/128 protocol:calipso,7
Then run the following PoC:
int fd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
// setup msghdr
int cmsg_size = 2;
int cmsg_len = 0x60;
struct msghdr msg;
struct sockaddr_in6 dest_addr;
struct cmsghdr * cmsg = (struct cmsghdr *) calloc(1,
sizeof(struct cmsghdr) + cmsg_len);
msg.msg_name = &dest_addr;
msg.msg_namelen = sizeof(dest_addr);
msg.msg_iov = NULL;
msg.msg_iovlen = 0;
msg.msg_control = cmsg;
msg.msg_controllen = cmsg_len;
msg.msg_flags = 0;
// setup sockaddr
dest_addr.sin6_family = AF_INET6;
dest_addr.sin6_port = htons(31337);
dest_addr.sin6_flowinfo = htonl(31337);
dest_addr.sin6_addr = in6addr_loopback;
dest_addr.sin6_scope_id = 31337;
// setup cmsghdr
cmsg->cmsg_len = cmsg_len;
cmsg->cmsg_level = IPPROTO_IPV6;
cmsg->cmsg_type = IPV6_HOPOPTS;
char * hop_hdr = (char *)cmsg + sizeof(struct cmsghdr);
hop_hdr[1] = 0x9; //set hop size - (0x9 + 1) * 8 = 80
sendmsg(fd, &msg, 0);
Fixes: 2917f57b6b ("calipso: Allow the lsm to label the skbuff directly.")
Suggested-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Will Rosenberg <whrosenb@asu.edu>
Acked-by: Paul Moore <paul@paul-moore.com>
Link: https://patch.msgid.link/20251219173637.797418-1-whrosenb@asu.edu
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit db5b4e39c4 ]
Over the years, syzbot found many ways to crash the kernel
in ip6gre_header() [1].
This involves team or bonding drivers ability to dynamically
change their dev->needed_headroom and/or dev->hard_header_len
In this particular crash mld_newpack() allocated an skb
with a too small reserve/headroom, and by the time mld_sendpack()
was called, syzbot managed to attach an ip6gre device.
[1]
skbuff: skb_under_panic: text:ffffffff8a1d69a8 len:136 put:40 head:ffff888059bc7000 data:ffff888059bc6fe8 tail:0x70 end:0x6c0 dev:team0
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:213 !
<TASK>
skb_under_panic net/core/skbuff.c:223 [inline]
skb_push+0xc3/0xe0 net/core/skbuff.c:2641
ip6gre_header+0xc8/0x790 net/ipv6/ip6_gre.c:1371
dev_hard_header include/linux/netdevice.h:3436 [inline]
neigh_connected_output+0x286/0x460 net/core/neighbour.c:1618
neigh_output include/net/neighbour.h:556 [inline]
ip6_finish_output2+0xfb3/0x1480 net/ipv6/ip6_output.c:136
__ip6_finish_output net/ipv6/ip6_output.c:-1 [inline]
ip6_finish_output+0x234/0x7d0 net/ipv6/ip6_output.c:220
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247
NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318
mld_sendpack+0x8d4/0xe60 net/ipv6/mcast.c:1855
mld_send_cr net/ipv6/mcast.c:2154 [inline]
mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693
Fixes: c12b395a46 ("gre: Support GRE over IPv6")
Reported-by: syzbot+43a2ebcf2a64b1102d64@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/693b002c.a70a0220.33cd7b.0033.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251211173550.2032674-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit f72514b3c5 ]
When an IPv6 Router Advertisement (RA) is received for a prefix, the
kernel creates the corresponding on-link route with flags RTF_ADDRCONF
and RTF_PREFIX_RT configured and RTF_EXPIRES if lifetime is set.
If later a user configures a static IPv6 address on the same prefix the
kernel clears the RTF_EXPIRES flag but it doesn't clear the RTF_ADDRCONF
and RTF_PREFIX_RT. When the next RA for that prefix is received, the
kernel sees the route as RA-learned and wrongly configures back the
lifetime. This is problematic because if the route expires, the static
address won't have the corresponding on-link route.
This fix clears the RTF_ADDRCONF and RTF_PREFIX_RT flags preventing that
the lifetime is configured when the next RA arrives. If the static
address is deleted, the route becomes RA-learned again.
Fixes: 14ef37b6d0 ("ipv6: fix route lookup in addrconf_prefix_rcv()")
Reported-by: Garri Djavadyan <g.djavadyan@gmail.com>
Closes: https://lore.kernel.org/netdev/ba807d39aca5b4dcf395cc11dca61a130a52cfd3.camel@gmail.com/
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20251115095939.6967-1-fmancera@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2a198bbec6 ]
This reverts commit f75a2804da.
With all states (whether user or kern) removed from the hashtables
during deletion, there's no need for synchronous destruction of
states. xfrm6_tunnel states still need to have been destroyed (which
will be the case when its last user is deleted (not destroyed)) so
that xfrm6_tunnel_free_spi removes it from the per-netns hashtable
before the netns is destroyed.
This has the benefit of skipping one synchronize_rcu per state (in
__xfrm_state_destroy(sync=true)) when we exit a netns.
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b441cf3f8c ]
The ipcomp fallback tunnels currently get deleted (from the various
lists and hashtables) as the last user state that needed that fallback
is destroyed (not deleted). If a reference to that user state still
exists, the fallback state will remain on the hashtables/lists,
triggering the WARN in xfrm_state_fini. Because of those remaining
references, the fix in commit f75a2804da ("xfrm: destroy xfrm_state
synchronously on net exit path") is not complete.
We recently fixed one such situation in TCP due to defered freeing of
skbs (commit 9b6412e697 ("tcp: drop secpath at the same time as we
currently drop dst")). This can also happen due to IP reassembly: skbs
with a secpath remain on the reassembly queue until netns
destruction. If we can't guarantee that the queues are flushed by the
time xfrm_state_fini runs, there may still be references to a (user)
xfrm_state, preventing the timely deletion of the corresponding
fallback state.
Instead of chasing each instance of skbs holding a secpath one by one,
this patch fixes the issue directly within xfrm, by deleting the
fallback state as soon as the last user state depending on it has been
deleted. Destruction will still happen when the final reference is
dropped.
A separate lockdep class for the fallback state is required since
we're going to lock x->tunnel while x is locked.
Fixes: 9d4139c769 ("netns xfrm: per-netns xfrm_state_all list")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 61fafbee6c ]
The GSO segmentation functions for ESP tunnel mode
(xfrm4_tunnel_gso_segment and xfrm6_tunnel_gso_segment) were
determining the inner packet's L2 protocol type by checking the static
x->inner_mode.family field from the xfrm state.
This is unreliable. In tunnel mode, the state's actual inner family
could be defined by x->inner_mode.family or by
x->inner_mode_iaf.family. Checking only the former can lead to a
mismatch with the actual packet being processed, causing GSO to create
segments with the wrong L2 header type.
This patch fixes the bug by deriving the inner mode directly from the
packet's inner protocol stored in XFRM_MODE_SKB_CB(skb)->protocol.
Instead of replicating the code, this patch modifies the
xfrm_ip2inner_mode helper function. It now correctly returns
&x->inner_mode if the selector family (x->sel.family) is already
specified, thereby handling both specific and AF_UNSPEC cases
appropriately.
With this change, ESP GSO can use xfrm_ip2inner_mode to get the
correct inner mode. It doesn't affect existing callers, as the updated
logic now mirrors the checks they were already performing externally.
Fixes: 26dbd66eab ("esp: choose the correct inner protocol for GSO on inter address family tunnels")
Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Maoyi XieandGreg Kroah-Hartman
Michael BommaritoandGreg Kroah-Hartman
Yilin ZhuandGreg Kroah-Hartman
Kuan-Ting ChenandGreg Kroah-Hartman
Andrea MayerandGreg Kroah-Hartman
Minhong HeandGreg Kroah-Hartman
Zhengchuan LiangandGreg Kroah-Hartman
Eric DumazetandGreg Kroah-Hartman
Paolo AbeniandGreg Kroah-Hartman
Pengpeng HouandGreg Kroah-Hartman
Yochai EisenrichandGreg Kroah-Hartman
Ren WeiandGreg Kroah-Hartman
Kuniyuki IwashimaandGreg Kroah-Hartman
Sabrina DubrocaandGreg Kroah-Hartman
Steffen KlassertandGreg Kroah-Hartman
Eric BiggersandGreg Kroah-Hartman
Jiayuan ChenandGreg Kroah-Hartman
Jakub KicinskiandGreg Kroah-Hartman
QanuxandSasha Levin
Shigeru YoshidaandGreg Kroah-Hartman
Jibin ZhangandGreg Kroah-Hartman
Fernando Fernandez ManceraandGreg Kroah-Hartman
Jianbo LiuandGreg Kroah-Hartman
Justin IurmanandGreg Kroah-Hartman
Jiayuan ChenandGreg Kroah-Hartman
Will RosenbergandGreg Kroah-Hartman