linux-stable.git/net, branch v5.4.296 Linux kernel stable tree net: ipv6: Discard next-hop MTU less than minimum link MTU 2025-07-17T16:25:06+00:00 Georg Kohmann geokohma@cisco.com 2020-10-07T12:53:02+00:00 ecdb232730f00a450f0623de5ac71b0b93c696fa commit 4a65dff81a04f874fa6915c7f069b4dc2c4010e4 upstream. When a ICMPV6_PKT_TOOBIG report a next-hop MTU that is less than the IPv6 minimum link MTU, the estimated path MTU is reduced to the minimum link MTU. This behaviour breaks TAHI IPv6 Core Conformance Test v6LC4.1.6: Packet Too Big Less than IPv6 MTU. Referring to RFC 8201 section 4: "If a node receives a Packet Too Big message reporting a next-hop MTU that is less than the IPv6 minimum link MTU, it must discard it. A node must not reduce its estimate of the Path MTU below the IPv6 minimum link MTU on receipt of a Packet Too Big message." Drop the path MTU update if reported MTU is less than the minimum link MTU. Signed-off-by: Georg Kohmann <geokohma@cisco.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: WangYuli <wangyuli@uniontech.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 4a65dff81a04f874fa6915c7f069b4dc2c4010e4 upstream.

When a ICMPV6_PKT_TOOBIG report a next-hop MTU that is less than the IPv6
minimum link MTU, the estimated path MTU is reduced to the minimum link
MTU. This behaviour breaks TAHI IPv6 Core Conformance Test v6LC4.1.6:
Packet Too Big Less than IPv6 MTU.

Referring to RFC 8201 section 4: "If a node receives a Packet Too Big
message reporting a next-hop MTU that is less than the IPv6 minimum link
MTU, it must discard it. A node must not reduce its estimate of the Path
MTU below the IPv6 minimum link MTU on receipt of a Packet Too Big
message."

Drop the path MTU update if reported MTU is less than the minimum link MTU.

Signed-off-by: Georg Kohmann <geokohma@cisco.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net: appletalk: Fix device refcount leak in atrtr_create() 2025-07-17T16:25:04+00:00 Kito Xu veritas501@foxmail.com 2025-07-09T03:52:51+00:00 b92bedf71f25303e203a4e657489d76691a58119 [ Upstream commit 711c80f7d8b163d3ecd463cd96f07230f488e750 ] When updating an existing route entry in atrtr_create(), the old device reference was not being released before assigning the new device, leading to a device refcount leak. Fix this by calling dev_put() to release the old device reference before holding the new one. Fixes: c7f905f0f6d4 ("[ATALK]: Add missing dev_hold() to atrtr_create().") Signed-off-by: Kito Xu <veritas501@foxmail.com> Link: https://patch.msgid.link/tencent_E1A26771CDAB389A0396D1681A90A49E5D09@qq.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 711c80f7d8b163d3ecd463cd96f07230f488e750 ]

When updating an existing route entry in atrtr_create(), the old device
reference was not being released before assigning the new device,
leading to a device refcount leak. Fix this by calling dev_put() to
release the old device reference before holding the new one.

Fixes: c7f905f0f6d4 ("[ATALK]: Add missing dev_hold() to atrtr_create().")
Signed-off-by: Kito Xu <veritas501@foxmail.com>
Link: https://patch.msgid.link/tencent_E1A26771CDAB389A0396D1681A90A49E5D09@qq.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
netlink: Fix rmem check in netlink_broadcast_deliver(). 2025-07-17T16:25:03+00:00 Kuniyuki Iwashima kuniyu@google.com 2025-07-11T05:32:07+00:00 07100f3ba5d7c65e6e792389f09bf6b8fc21aedb commit a3c4a125ec725cefb40047eb05ff9eafd57830b4 upstream. We need to allow queuing at least one skb even when skb is larger than sk->sk_rcvbuf. The cited commit made a mistake while converting a condition in netlink_broadcast_deliver(). Let's correct the rmem check for the allow-one-skb rule. Fixes: ae8f160e7eb24 ("netlink: Fix wraparounds of sk->sk_rmem_alloc.") Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250711053208.2965945-1-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit a3c4a125ec725cefb40047eb05ff9eafd57830b4 upstream.

We need to allow queuing at least one skb even when skb is
larger than sk->sk_rcvbuf.

The cited commit made a mistake while converting a condition
in netlink_broadcast_deliver().

Let's correct the rmem check for the allow-one-skb rule.

Fixes: ae8f160e7eb24 ("netlink: Fix wraparounds of sk->sk_rmem_alloc.")
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250711053208.2965945-1-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
netlink: make sure we allow at least one dump skb 2025-07-17T16:25:03+00:00 Jakub Kicinski kuba@kernel.org 2025-07-11T00:11:21+00:00 23791e9242a954f4b4676aab3e2d915301ef6413 commit a215b5723922f8099078478122f02100e489cb80 upstream. Commit under Fixes tightened up the memory accounting for Netlink sockets. Looks like the accounting is too strict for some existing use cases, Marek reported issues with nl80211 / WiFi iw CLI. To reduce number of iterations Netlink dumps try to allocate messages based on the size of the buffer passed to previous recvmsg() calls. If user space uses a larger buffer in recvmsg() than sk_rcvbuf we will allocate an skb we won't be able to queue. Make sure we always allow at least one skb to be queued. Same workaround is already present in netlink_attachskb(). Alternative would be to cap the allocation size to rcvbuf - rmem_alloc but as I said, the workaround is already present in other places. Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> Link: https://lore.kernel.org/9794af18-4905-46c6-b12c-365ea2f05858@samsung.com Fixes: ae8f160e7eb2 ("netlink: Fix wraparounds of sk->sk_rmem_alloc.") Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250711001121.3649033-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit a215b5723922f8099078478122f02100e489cb80 upstream.

Commit under Fixes tightened up the memory accounting for Netlink
sockets. Looks like the accounting is too strict for some existing
use cases, Marek reported issues with nl80211 / WiFi iw CLI.

To reduce number of iterations Netlink dumps try to allocate
messages based on the size of the buffer passed to previous
recvmsg() calls. If user space uses a larger buffer in recvmsg()
than sk_rcvbuf we will allocate an skb we won't be able to queue.

Make sure we always allow at least one skb to be queued.
Same workaround is already present in netlink_attachskb().
Alternative would be to cap the allocation size to
  rcvbuf - rmem_alloc
but as I said, the workaround is already present in other places.

Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/9794af18-4905-46c6-b12c-365ea2f05858@samsung.com
Fixes: ae8f160e7eb2 ("netlink: Fix wraparounds of sk->sk_rmem_alloc.")
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250711001121.3649033-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rxrpc: Fix oops due to non-existence of prealloc backlog struct 2025-07-17T16:25:02+00:00 David Howells dhowells@redhat.com 2025-07-08T21:15:04+00:00 bf0ca6a1bc4fb904b598137c6718785a107e3adf commit 880a88f318cf1d2a0f4c0a7ff7b07e2062b434a4 upstream. If an AF_RXRPC service socket is opened and bound, but calls are preallocated, then rxrpc_alloc_incoming_call() will oops because the rxrpc_backlog struct doesn't get allocated until the first preallocation is made. Fix this by returning NULL from rxrpc_alloc_incoming_call() if there is no backlog struct. This will cause the incoming call to be aborted. Reported-by: Junvyyang, Tencent Zhuque Lab <zhuque@tencent.com> Suggested-by: Junvyyang, Tencent Zhuque Lab <zhuque@tencent.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: LePremierHomme <kwqcheii@proton.me> cc: Marc Dionne <marc.dionne@auristor.com> cc: Willy Tarreau <w@1wt.eu> cc: Simon Horman <horms@kernel.org> cc: linux-afs@lists.infradead.org Link: https://patch.msgid.link/20250708211506.2699012-3-dhowells@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 880a88f318cf1d2a0f4c0a7ff7b07e2062b434a4 upstream.

If an AF_RXRPC service socket is opened and bound, but calls are
preallocated, then rxrpc_alloc_incoming_call() will oops because the
rxrpc_backlog struct doesn't get allocated until the first preallocation is
made.

Fix this by returning NULL from rxrpc_alloc_incoming_call() if there is no
backlog struct.  This will cause the incoming call to be aborted.

Reported-by: Junvyyang, Tencent Zhuque Lab <zhuque@tencent.com>
Suggested-by: Junvyyang, Tencent Zhuque Lab <zhuque@tencent.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: LePremierHomme <kwqcheii@proton.me>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Willy Tarreau <w@1wt.eu>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
Link: https://patch.msgid.link/20250708211506.2699012-3-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/sched: Abort __tc_modify_qdisc if parent class does not exist 2025-07-17T16:25:02+00:00 Victor Nogueira victor@mojatatu.com 2025-07-07T21:08:01+00:00 923a276c74e25073ae391e930792ac86a9f77f1e [ Upstream commit ffdde7bf5a439aaa1955ebd581f5c64ab1533963 ] Lion's patch [1] revealed an ancient bug in the qdisc API. Whenever a user creates/modifies a qdisc specifying as a parent another qdisc, the qdisc API will, during grafting, detect that the user is not trying to attach to a class and reject. However grafting is performed after qdisc_create (and thus the qdiscs' init callback) is executed. In qdiscs that eventually call qdisc_tree_reduce_backlog during init or change (such as fq, hhf, choke, etc), an issue arises. For example, executing the following commands: sudo tc qdisc add dev lo root handle a: htb default 2 sudo tc qdisc add dev lo parent a: handle beef fq Qdiscs such as fq, hhf, choke, etc unconditionally invoke qdisc_tree_reduce_backlog() in their control path init() or change() which then causes a failure to find the child class; however, that does not stop the unconditional invocation of the assumed child qdisc's qlen_notify with a null class. All these qdiscs make the assumption that class is non-null. The solution is ensure that qdisc_leaf() which looks up the parent class, and is invoked prior to qdisc_create(), should return failure on not finding the class. In this patch, we leverage qdisc_leaf to return ERR_PTRs whenever the parentid doesn't correspond to a class, so that we can detect it earlier on and abort before qdisc_create is called. [1] https://lore.kernel.org/netdev/d912cbd7-193b-4269-9857-525bee8bbb6a@gmail.com/ Fixes: 5e50da01d0ce ("[NET_SCHED]: Fix endless loops (part 2): "simple" qdiscs") Reported-by: syzbot+d8b58d7b0ad89a678a16@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/68663c93.a70a0220.5d25f.0857.GAE@google.com/ Reported-by: syzbot+5eccb463fa89309d8bdc@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/68663c94.a70a0220.5d25f.0858.GAE@google.com/ Reported-by: syzbot+1261670bbdefc5485a06@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/686764a5.a00a0220.c7b3.0013.GAE@google.com/ Reported-by: syzbot+15b96fc3aac35468fe77@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/686764a5.a00a0220.c7b3.0014.GAE@google.com/ Reported-by: syzbot+4dadc5aecf80324d5a51@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/68679e81.a70a0220.29cf51.0016.GAE@google.com/ Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Victor Nogueira <victor@mojatatu.com> Link: https://patch.msgid.link/20250707210801.372995-1-victor@mojatatu.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit ffdde7bf5a439aaa1955ebd581f5c64ab1533963 ]

Lion's patch [1] revealed an ancient bug in the qdisc API.
Whenever a user creates/modifies a qdisc specifying as a parent another
qdisc, the qdisc API will, during grafting, detect that the user is
not trying to attach to a class and reject. However grafting is
performed after qdisc_create (and thus the qdiscs' init callback) is
executed. In qdiscs that eventually call qdisc_tree_reduce_backlog
during init or change (such as fq, hhf, choke, etc), an issue
arises. For example, executing the following commands:

sudo tc qdisc add dev lo root handle a: htb default 2
sudo tc qdisc add dev lo parent a: handle beef fq

Qdiscs such as fq, hhf, choke, etc unconditionally invoke
qdisc_tree_reduce_backlog() in their control path init() or change() which
then causes a failure to find the child class; however, that does not stop
the unconditional invocation of the assumed child qdisc's qlen_notify with
a null class. All these qdiscs make the assumption that class is non-null.

The solution is ensure that qdisc_leaf() which looks up the parent
class, and is invoked prior to qdisc_create(), should return failure on
not finding the class.
In this patch, we leverage qdisc_leaf to return ERR_PTRs whenever the
parentid doesn't correspond to a class, so that we can detect it
earlier on and abort before qdisc_create is called.

[1] https://lore.kernel.org/netdev/d912cbd7-193b-4269-9857-525bee8bbb6a@gmail.com/

Fixes: 5e50da01d0ce ("[NET_SCHED]: Fix endless loops (part 2): "simple" qdiscs")
Reported-by: syzbot+d8b58d7b0ad89a678a16@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/68663c93.a70a0220.5d25f.0857.GAE@google.com/
Reported-by: syzbot+5eccb463fa89309d8bdc@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/68663c94.a70a0220.5d25f.0858.GAE@google.com/
Reported-by: syzbot+1261670bbdefc5485a06@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/686764a5.a00a0220.c7b3.0013.GAE@google.com/
Reported-by: syzbot+15b96fc3aac35468fe77@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/686764a5.a00a0220.c7b3.0014.GAE@google.com/
Reported-by: syzbot+4dadc5aecf80324d5a51@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/68679e81.a70a0220.29cf51.0016.GAE@google.com/
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Link: https://patch.msgid.link/20250707210801.372995-1-victor@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
atm: clip: Fix NULL pointer dereference in vcc_sendmsg() 2025-07-17T16:25:02+00:00 Yue Haibing yuehaibing@huawei.com 2025-07-05T08:52:28+00:00 9ec7e943aee5c28c173933f9defd40892fb3be3d [ Upstream commit 22fc46cea91df3dce140a7dc6847c6fcf0354505 ] atmarpd_dev_ops does not implement the send method, which may cause crash as bellow. BUG: kernel NULL pointer dereference, address: 0000000000000000 PGD 0 P4D 0 Oops: Oops: 0010 [#1] SMP KASAN NOPTI CPU: 0 UID: 0 PID: 5324 Comm: syz.0.0 Not tainted 6.15.0-rc6-syzkaller-00346-g5723cc3450bc #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:0x0 Code: Unable to access opcode bytes at 0xffffffffffffffd6. RSP: 0018:ffffc9000d3cf778 EFLAGS: 00010246 RAX: 1ffffffff1910dd1 RBX: 00000000000000c0 RCX: dffffc0000000000 RDX: ffffc9000dc82000 RSI: ffff88803e4c4640 RDI: ffff888052cd0000 RBP: ffffc9000d3cf8d0 R08: ffff888052c9143f R09: 1ffff1100a592287 R10: dffffc0000000000 R11: 0000000000000000 R12: 1ffff92001a79f00 R13: ffff888052cd0000 R14: ffff88803e4c4640 R15: ffffffff8c886e88 FS: 00007fbc762566c0(0000) GS:ffff88808d6c2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 0000000041f1b000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> vcc_sendmsg+0xa10/0xc50 net/atm/common.c:644 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x219/0x270 net/socket.c:727 ____sys_sendmsg+0x52d/0x830 net/socket.c:2566 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620 __sys_sendmmsg+0x227/0x430 net/socket.c:2709 __do_sys_sendmmsg net/socket.c:2736 [inline] __se_sys_sendmmsg net/socket.c:2733 [inline] __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2733 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+e34e5e6b5eddb0014def@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/682f82d5.a70a0220.1765ec.0143.GAE@google.com/T Signed-off-by: Yue Haibing <yuehaibing@huawei.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250705085228.329202-1-yuehaibing@huawei.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 22fc46cea91df3dce140a7dc6847c6fcf0354505 ]

atmarpd_dev_ops does not implement the send method, which may cause crash
as bellow.

BUG: kernel NULL pointer dereference, address: 0000000000000000
PGD 0 P4D 0
Oops: Oops: 0010 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5324 Comm: syz.0.0 Not tainted 6.15.0-rc6-syzkaller-00346-g5723cc3450bc #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc9000d3cf778 EFLAGS: 00010246
RAX: 1ffffffff1910dd1 RBX: 00000000000000c0 RCX: dffffc0000000000
RDX: ffffc9000dc82000 RSI: ffff88803e4c4640 RDI: ffff888052cd0000
RBP: ffffc9000d3cf8d0 R08: ffff888052c9143f R09: 1ffff1100a592287
R10: dffffc0000000000 R11: 0000000000000000 R12: 1ffff92001a79f00
R13: ffff888052cd0000 R14: ffff88803e4c4640 R15: ffffffff8c886e88
FS:  00007fbc762566c0(0000) GS:ffff88808d6c2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000041f1b000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 vcc_sendmsg+0xa10/0xc50 net/atm/common.c:644
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:727
 ____sys_sendmsg+0x52d/0x830 net/socket.c:2566
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620
 __sys_sendmmsg+0x227/0x430 net/socket.c:2709
 __do_sys_sendmmsg net/socket.c:2736 [inline]
 __se_sys_sendmmsg net/socket.c:2733 [inline]
 __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2733
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+e34e5e6b5eddb0014def@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/682f82d5.a70a0220.1765ec.0143.GAE@google.com/T
Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250705085228.329202-1-yuehaibing@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
atm: clip: Fix infinite recursive call of clip_push(). 2025-07-17T16:25:02+00:00 Kuniyuki Iwashima kuniyu@google.com 2025-07-04T06:23:53+00:00 f493f31a63847624fd3199ac836a8bd8828e50e2 [ Upstream commit c489f3283dbfc0f3c00c312149cae90d27552c45 ] syzbot reported the splat below. [0] This happens if we call ioctl(ATMARP_MKIP) more than once. During the first call, clip_mkip() sets clip_push() to vcc->push(), and the second call copies it to clip_vcc->old_push(). Later, when the socket is close()d, vcc_destroy_socket() passes NULL skb to clip_push(), which calls clip_vcc->old_push(), triggering the infinite recursion. Let's prevent the second ioctl(ATMARP_MKIP) by checking vcc->user_back, which is allocated by the first call as clip_vcc. Note also that we use lock_sock() to prevent racy calls. [0]: BUG: TASK stack guard page was hit at ffffc9000d66fff8 (stack is ffffc9000d670000..ffffc9000d678000) Oops: stack guard page: 0000 [#1] SMP KASAN NOPTI CPU: 0 UID: 0 PID: 5322 Comm: syz.0.0 Not tainted 6.16.0-rc4-syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:clip_push+0x5/0x720 net/atm/clip.c:191 Code: e0 8f aa 8c e8 1c ad 5b fa eb ae 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 <41> 57 41 56 41 55 41 54 53 48 83 ec 20 48 89 f3 49 89 fd 48 bd 00 RSP: 0018:ffffc9000d670000 EFLAGS: 00010246 RAX: 1ffff1100235a4a5 RBX: ffff888011ad2508 RCX: ffff8880003c0000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888037f01000 RBP: dffffc0000000000 R08: ffffffff8fa104f7 R09: 1ffffffff1f4209e R10: dffffc0000000000 R11: ffffffff8a99b300 R12: ffffffff8a99b300 R13: ffff888037f01000 R14: ffff888011ad2500 R15: ffff888037f01578 FS: 000055557ab6d500(0000) GS:ffff88808d250000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffc9000d66fff8 CR3: 0000000043172000 CR4: 0000000000352ef0 Call Trace: <TASK> clip_push+0x6dc/0x720 net/atm/clip.c:200 clip_push+0x6dc/0x720 net/atm/clip.c:200 clip_push+0x6dc/0x720 net/atm/clip.c:200 ... clip_push+0x6dc/0x720 net/atm/clip.c:200 clip_push+0x6dc/0x720 net/atm/clip.c:200 clip_push+0x6dc/0x720 net/atm/clip.c:200 vcc_destroy_socket net/atm/common.c:183 [inline] vcc_release+0x157/0x460 net/atm/common.c:205 __sock_release net/socket.c:647 [inline] sock_close+0xc0/0x240 net/socket.c:1391 __fput+0x449/0xa70 fs/file_table.c:465 task_work_run+0x1d1/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:114 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff31c98e929 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fffb5aa1f78 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 0000000000012747 RCX: 00007ff31c98e929 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007ff31cbb7ba0 R08: 0000000000000001 R09: 0000000db5aa226f R10: 00007ff31c7ff030 R11: 0000000000000246 R12: 00007ff31cbb608c R13: 00007ff31cbb6080 R14: ffffffffffffffff R15: 00007fffb5aa2090 </TASK> Modules linked in: Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+0c77cccd6b7cd917b35a@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=2371d94d248d126c1eb1 Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250704062416.1613927-4-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c489f3283dbfc0f3c00c312149cae90d27552c45 ]

syzbot reported the splat below. [0]

This happens if we call ioctl(ATMARP_MKIP) more than once.

During the first call, clip_mkip() sets clip_push() to vcc->push(),
and the second call copies it to clip_vcc->old_push().

Later, when the socket is close()d, vcc_destroy_socket() passes
NULL skb to clip_push(), which calls clip_vcc->old_push(),
triggering the infinite recursion.

Let's prevent the second ioctl(ATMARP_MKIP) by checking
vcc->user_back, which is allocated by the first call as clip_vcc.

Note also that we use lock_sock() to prevent racy calls.

[0]:
BUG: TASK stack guard page was hit at ffffc9000d66fff8 (stack is ffffc9000d670000..ffffc9000d678000)
Oops: stack guard page: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5322 Comm: syz.0.0 Not tainted 6.16.0-rc4-syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:clip_push+0x5/0x720 net/atm/clip.c:191
Code: e0 8f aa 8c e8 1c ad 5b fa eb ae 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 <41> 57 41 56 41 55 41 54 53 48 83 ec 20 48 89 f3 49 89 fd 48 bd 00
RSP: 0018:ffffc9000d670000 EFLAGS: 00010246
RAX: 1ffff1100235a4a5 RBX: ffff888011ad2508 RCX: ffff8880003c0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888037f01000
RBP: dffffc0000000000 R08: ffffffff8fa104f7 R09: 1ffffffff1f4209e
R10: dffffc0000000000 R11: ffffffff8a99b300 R12: ffffffff8a99b300
R13: ffff888037f01000 R14: ffff888011ad2500 R15: ffff888037f01578
FS:  000055557ab6d500(0000) GS:ffff88808d250000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc9000d66fff8 CR3: 0000000043172000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 clip_push+0x6dc/0x720 net/atm/clip.c:200
 clip_push+0x6dc/0x720 net/atm/clip.c:200
 clip_push+0x6dc/0x720 net/atm/clip.c:200
...
 clip_push+0x6dc/0x720 net/atm/clip.c:200
 clip_push+0x6dc/0x720 net/atm/clip.c:200
 clip_push+0x6dc/0x720 net/atm/clip.c:200
 vcc_destroy_socket net/atm/common.c:183 [inline]
 vcc_release+0x157/0x460 net/atm/common.c:205
 __sock_release net/socket.c:647 [inline]
 sock_close+0xc0/0x240 net/socket.c:1391
 __fput+0x449/0xa70 fs/file_table.c:465
 task_work_run+0x1d1/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:114
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff31c98e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffb5aa1f78 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 0000000000012747 RCX: 00007ff31c98e929
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007ff31cbb7ba0 R08: 0000000000000001 R09: 0000000db5aa226f
R10: 00007ff31c7ff030 R11: 0000000000000246 R12: 00007ff31cbb608c
R13: 00007ff31cbb6080 R14: ffffffffffffffff R15: 00007fffb5aa2090
 </TASK>
Modules linked in:

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+0c77cccd6b7cd917b35a@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=2371d94d248d126c1eb1
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250704062416.1613927-4-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
atm: clip: Fix memory leak of struct clip_vcc. 2025-07-17T16:25:02+00:00 Kuniyuki Iwashima kuniyu@google.com 2025-07-04T06:23:52+00:00 2fb37ab3226606cbfc9b2b6f9e301b0b735734c5 [ Upstream commit 62dba28275a9a3104d4e33595c7b3328d4032d8d ] ioctl(ATMARP_MKIP) allocates struct clip_vcc and set it to vcc->user_back. The code assumes that vcc_destroy_socket() passes NULL skb to vcc->push() when the socket is close()d, and then clip_push() frees clip_vcc. However, ioctl(ATMARPD_CTRL) sets NULL to vcc->push() in atm_init_atmarp(), resulting in memory leak. Let's serialise two ioctl() by lock_sock() and check vcc->push() in atm_init_atmarp() to prevent memleak. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250704062416.1613927-3-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 62dba28275a9a3104d4e33595c7b3328d4032d8d ]

ioctl(ATMARP_MKIP) allocates struct clip_vcc and set it to
vcc->user_back.

The code assumes that vcc_destroy_socket() passes NULL skb
to vcc->push() when the socket is close()d, and then clip_push()
frees clip_vcc.

However, ioctl(ATMARPD_CTRL) sets NULL to vcc->push() in
atm_init_atmarp(), resulting in memory leak.

Let's serialise two ioctl() by lock_sock() and check vcc->push()
in atm_init_atmarp() to prevent memleak.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250704062416.1613927-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
atm: clip: Fix potential null-ptr-deref in to_atmarpd(). 2025-07-17T16:25:02+00:00 Kuniyuki Iwashima kuniyu@google.com 2025-07-04T06:23:51+00:00 a4c5785feb979cd996a99cfaad8bf353b2e79301 [ Upstream commit 706cc36477139c1616a9b2b96610a8bb520b7119 ] atmarpd is protected by RTNL since commit f3a0592b37b8 ("[ATM]: clip causes unregister hang"). However, it is not enough because to_atmarpd() is called without RTNL, especially clip_neigh_solicit() / neigh_ops->solicit() is unsleepable. Also, there is no RTNL dependency around atmarpd. Let's use a private mutex and RCU to protect access to atmarpd in to_atmarpd(). Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250704062416.1613927-2-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 706cc36477139c1616a9b2b96610a8bb520b7119 ]

atmarpd is protected by RTNL since commit f3a0592b37b8 ("[ATM]: clip
causes unregister hang").

However, it is not enough because to_atmarpd() is called without RTNL,
especially clip_neigh_solicit() / neigh_ops->solicit() is unsleepable.

Also, there is no RTNL dependency around atmarpd.

Let's use a private mutex and RCU to protect access to atmarpd in
to_atmarpd().

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250704062416.1613927-2-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>