linux-stable.git/net/core/skbuff.c, branch linux-6.13.y

ipvs: Always clear ipvs_property flag in skb_scrub_packet()

2025-03-07T17:26:58+00:00

[ Upstream commit de2c211868b9424f9aa9b3432c4430825bafb41b ]

We found an issue when using bpf_redirect with ipvs NAT mode after
commit ff70202b2d1a ("dev_forward_skb: do not scrub skb mark within
the same name space"). Particularly, we use bpf_redirect to return
the skb directly back to the netif it comes from, i.e., xnet is
false in skb_scrub_packet(), and then ipvs_property is preserved
and SNAT is skipped in the rx path.

ipvs_property has been already cleared when netns is changed in
commit 2b5ec1a5f973 ("netfilter/ipvs: clear ipvs_property flag when
SKB net namespace changed"). This patch just clears it in spite of
netns.

Fixes: 2b5ec1a5f973 ("netfilter/ipvs: clear ipvs_property flag when SKB net namespace changed")
Signed-off-by: Philo Lu 
Acked-by: Julian Anastasov 
Link: https://patch.msgid.link/20250222033518.126087-1-lulie@linux.alibaba.com
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

net: allow small head cache usage with large MAX_SKB_FRAGS values

2025-02-27T12:34:15+00:00

[ Upstream commit 14ad6ed30a10afbe91b0749d6378285f4225d482 ]

Sabrina reported the following splat:

    WARNING: CPU: 0 PID: 1 at net/core/dev.c:6935 netif_napi_add_weight_locked+0x8f2/0xba0
    Modules linked in:
    CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.14.0-rc1-net-00092-g011b03359038 #996
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
    RIP: 0010:netif_napi_add_weight_locked+0x8f2/0xba0
    Code: e8 c3 e6 6a fe 48 83 c4 28 5b 5d 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc c7 44 24 10 ff ff ff ff e9 8f fb ff ff e8 9e e6 6a fe <0f> 0b e9 d3 fe ff ff e8 92 e6 6a fe 48 8b 04 24 be ff ff ff ff 48
    RSP: 0000:ffffc9000001fc60 EFLAGS: 00010293
    RAX: 0000000000000000 RBX: ffff88806ce48128 RCX: 1ffff11001664b9e
    RDX: ffff888008f00040 RSI: ffffffff8317ca42 RDI: ffff88800b325cb6
    RBP: ffff88800b325c40 R08: 0000000000000001 R09: ffffed100167502c
    R10: ffff88800b3a8163 R11: 0000000000000000 R12: ffff88800ac1c168
    R13: ffff88800ac1c168 R14: ffff88800ac1c168 R15: 0000000000000007
    FS:  0000000000000000(0000) GS:ffff88806ce00000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: ffff888008201000 CR3: 0000000004c94001 CR4: 0000000000370ef0
    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
    Call Trace:
    
    gro_cells_init+0x1ba/0x270
    xfrm_input_init+0x4b/0x2a0
    xfrm_init+0x38/0x50
    ip_rt_init+0x2d7/0x350
    ip_init+0xf/0x20
    inet_init+0x406/0x590
    do_one_initcall+0x9d/0x2e0
    do_initcalls+0x23b/0x280
    kernel_init_freeable+0x445/0x490
    kernel_init+0x20/0x1d0
    ret_from_fork+0x46/0x80
    ret_from_fork_asm+0x1a/0x30
    
    irq event stamp: 584330
    hardirqs last  enabled at (584338): [] __up_console_sem+0x77/0xb0
    hardirqs last disabled at (584345): [] __up_console_sem+0x5c/0xb0
    softirqs last  enabled at (583242): [] netlink_insert+0x14d/0x470
    softirqs last disabled at (583754): [] netif_napi_add_weight_locked+0x77d/0xba0

on kernel built with MAX_SKB_FRAGS=45, where SKB_WITH_OVERHEAD(1024)
is smaller than GRO_MAX_HEAD.

Such built additionally contains the revert of the single page frag cache
so that napi_get_frags() ends up using the page frag allocator, triggering
the splat.

Note that the underlying issue is independent from the mentioned
revert; address it ensuring that the small head cache will fit either TCP
and GRO allocation and updating napi_alloc_skb() and __netdev_alloc_skb()
to select kmalloc() usage for any allocation fitting such cache.

Reported-by: Sabrina Dubroca 
Suggested-by: Eric Dumazet 
Fixes: 3948b05950fd ("net: introduce a config option to tweak MAX_SKB_FRAGS")
Reviewed-by: Eric Dumazet 
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

mm: page_frag: avoid caller accessing 'page_frag_cache' directly

2024-11-11T18:56:27+00:00

Use appropriate frag_page API instead of caller accessing
'page_frag_cache' directly.

CC: Andrew Morton 
CC: Linux-MM 
Signed-off-by: Yunsheng Lin 
Reviewed-by: Alexander Duyck 
Acked-by: Chuck Lever 
Link: https://patch.msgid.link/20241028115343.3405838-5-linyunsheng@huawei.com
Signed-off-by: Jakub Kicinski

net-timestamp: namespacify the sysctl_tstamp_allow_data

2024-10-08T22:33:11+00:00

Let it be tuned in per netns by admins.

Signed-off-by: Jason Xing 
Reviewed-by: Kuniyuki Iwashima 
Reviewed-by: Eric Dumazet 
Reviewed-by: Willem de Bruijn 
Link: https://patch.msgid.link/20241005222609.94980-1-kerneljasonxing@gmail.com
Signed-off-by: Jakub Kicinski

net: add support for skbs with unreadable frags

2024-09-12T03:44:31+00:00

For device memory TCP, we expect the skb headers to be available in host
memory for access, and we expect the skb frags to be in device memory
and unaccessible to the host. We expect there to be no mixing and
matching of device memory frags (unaccessible) with host memory frags
(accessible) in the same skb.

Add a skb->devmem flag which indicates whether the frags in this skb
are device memory frags or not.

__skb_fill_netmem_desc() now checks frags added to skbs for net_iov,
and marks the skb as skb->devmem accordingly.

Add checks through the network stack to avoid accessing the frags of
devmem skbs and avoid coalescing devmem skbs with non devmem skbs.

Signed-off-by: Willem de Bruijn 
Signed-off-by: Kaiyuan Zhang 
Signed-off-by: Mina Almasry 
Reviewed-by: Eric Dumazet 
Reviewed-by: Jakub Kicinski 
Link: https://patch.msgid.link/20240910171458.219195-9-almasrymina@google.com
Signed-off-by: Jakub Kicinski

net: support non paged skb frags

2024-09-12T03:44:31+00:00

Make skb_frag_page() fail in the case where the frag is not backed
by a page, and fix its relevant callers to handle this case.

Signed-off-by: Mina Almasry 
Reviewed-by: Eric Dumazet 
Reviewed-by: Jakub Kicinski 
Link: https://patch.msgid.link/20240910171458.219195-8-almasrymina@google.com
Signed-off-by: Jakub Kicinski

page_pool: devmem support

2024-09-12T03:44:31+00:00

Convert netmem to be a union of struct page and struct netmem. Overload
the LSB of struct netmem* to indicate that it's a net_iov, otherwise
it's a page.

Currently these entries in struct page are rented by the page_pool and
used exclusively by the net stack:

struct {
	unsigned long pp_magic;
	struct page_pool *pp;
	unsigned long _pp_mapping_pad;
	unsigned long dma_addr;
	atomic_long_t pp_ref_count;
};

Mirror these (and only these) entries into struct net_iov and implement
netmem helpers that can access these common fields regardless of
whether the underlying type is page or net_iov.

Implement checks for net_iov in netmem helpers which delegate to mm
APIs, to ensure net_iov are never passed to the mm stack.

Signed-off-by: Mina Almasry 
Reviewed-by: Pavel Begunkov 
Acked-by: Jakub Kicinski 
Link: https://patch.msgid.link/20240910171458.219195-6-almasrymina@google.com
Signed-off-by: Jakub Kicinski

Merge tag 'ipsec-next-2024-09-10' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next

2024-09-11T02:00:47+00:00

Steffen Klassert says:

====================
pull request (net-next): ipsec-next 2024-09-10

1) Remove an unneeded WARN_ON on packet offload.
   From Patrisious Haddad.

2) Add a copy from skb_seq_state to buffer function.
   This is needed for the upcomming IPTFS patchset.
   From Christian Hopps.

3) Spelling fix in xfrm.h.
   From Simon Horman.

4) Speed up xfrm policy insertions.
   From Florian Westphal.

5) Add and revert a patch to support xfrm interfaces
   for packet offload. This patch was just half cooked.

6) Extend usage of the new xfrm_policy_is_dead_or_sk helper.
   From Florian Westphal.

7) Update comments on sdb and xfrm_policy.
   From Florian Westphal.

8) Fix a null pointer dereference in the new policy insertion
   code From Florian Westphal.

9) Fix an uninitialized variable in the new policy insertion
   code. From Nathan Chancellor.

* tag 'ipsec-next-2024-09-10' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next:
  xfrm: policy: Restore dir assignments in xfrm_hash_rebuild()
  xfrm: policy: fix null dereference
  Revert "xfrm: add SA information to the offloaded packet"
  xfrm: minor update to sdb and xfrm_policy comments
  xfrm: policy: use recently added helper in more places
  xfrm: add SA information to the offloaded packet
  xfrm: policy: remove remaining use of inexact list
  xfrm: switch migrate to xfrm_policy_lookup_bytype
  xfrm: policy: don't iterate inexact policies twice at insert time
  selftests: add xfrm policy insertion speed test script
  xfrm: Correct spelling in xfrm.h
  net: add copy from skb_seq_state to buffer function
  xfrm: Remove documentation WARN_ON to limit return values for offloaded SA
====================

Link: https://patch.msgid.link/20240910065507.2436394-1-steffen.klassert@secunet.com
Signed-off-by: Jakub Kicinski

tc: adjust network header after 2nd vlan push

2024-08-27T09:37:42+00:00


skb network header of the single-tagged vlan packet continues to point the
vlan payload (e.g. IP) after second vlan tag is pushed by tc act_vlan. This
causes problem at the dissector which expects double-tagged packet network
header to point to the inner vlan.

The fix is to adjust network header in tcf_act_vlan.c but requires
refactoring of skb_vlan_push function.


Consider the following shell script snippet configuring TC rules on the
veth interface:

ip link add veth0 type veth peer veth1
ip link set veth0 up
ip link set veth1 up

tc qdisc add dev veth0 clsact

tc filter add dev veth0 ingress pref 10 chain 0 flower \
	num_of_vlans 2 cvlan_ethtype 0x800 action goto chain 5
tc filter add dev veth0 ingress pref 20 chain 0 flower \
	num_of_vlans 1 action vlan push id 100 \
	protocol 0x8100 action goto chain 5
tc filter add dev veth0 ingress pref 30 chain 5 flower \
	num_of_vlans 2 cvlan_ethtype 0x800 action simple sdata "success"

Sending double-tagged vlan packet with the IP payload inside:

cat <protocol;
	} else {
		vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan),
					    data, hlen, &_vlan);
		if (!vlan) {
			fdret = FLOW_DISSECT_RET_OUT_BAD;
			break;
		}

		proto = vlan->h_vlan_encapsulated_proto;
		nhoff += sizeof(*vlan);
	}

The "else" clause above gets the protocol of the encapsulated packet from
the skb data at the network header location. printk debugging has showed
that in the good double-tagged packet case proto is
htons(0x800 == ETH_P_IP) as expected. However in the single-tagged packet
case proto is garbage leading to the failure to match tc filter 30.

proto is being set from the skb header pointed by nhoff parameter which is
defined at the beginning of __skb_flow_dissect
(net/core/flow_dissector.c:1055 in the current version):

		nhoff = skb_network_offset(skb);

Therefore the culprit seems to be that the skb network offset is different
between double-tagged packet received from the interface and single-tagged
packet having its vlan tag pushed by TC.

Lets look at the interesting points of the lifetime of the single/double
tagged packets as they traverse our packet flow.

Both of them will start at __netif_receive_skb_core where the first vlan
tag will be stripped:

	if (eth_type_vlan(skb->protocol)) {
		skb = skb_vlan_untag(skb);
		if (unlikely(!skb))
			goto out;
	}

At this stage in double-tagged case skb->data points to the second vlan tag
while in single-tagged case skb->data points to the network (eg. IP)
header.

Looking at TC vlan push action (net/sched/act_vlan.c) we have the following
code at tcf_vlan_act (interesting points are in square brackets):

	if (skb_at_tc_ingress(skb))
[1]		skb_push_rcsum(skb, skb->mac_len);

	....

	case TCA_VLAN_ACT_PUSH:
		err = skb_vlan_push(skb, p->tcfv_push_proto, p->tcfv_push_vid |
				    (p->tcfv_push_prio << VLAN_PRIO_SHIFT),
				    0);
		if (err)
			goto drop;
		break;

	....

out:
	if (skb_at_tc_ingress(skb))
[3]		skb_pull_rcsum(skb, skb->mac_len);

And skb_vlan_push (net/core/skbuff.c:6204) function does:

		err = __vlan_insert_tag(skb, skb->vlan_proto,
					skb_vlan_tag_get(skb));
		if (err)
			return err;

		skb->protocol = skb->vlan_proto;
[2]		skb->mac_len += VLAN_HLEN;

in the case of pushing the second tag. Lets look at what happens with
skb->data of the single-tagged packet at each of the above points:

1. As a result of the skb_push_rcsum, skb->data is moved back to the start
   of the packet.

2. First VLAN tag is moved from the skb into packet buffer, skb->mac_len is
   incremented, skb->data still points to the start of the packet.

3. As a result of the skb_pull_rcsum, skb->data is moved forward by the
   modified skb->mac_len, thus pointing to the network header again.

Then __skb_flow_dissect will get confused by having double-tagged vlan
packet with the skb->data at the network header.

The solution for the bug is to preserve "skb->data at second vlan header"
semantics in the skb_vlan_push function. We do this by manipulating
skb->network_header rather than skb->mac_len. skb_vlan_push callers are
updated to do skb_reset_mac_len.

Signed-off-by: Boris Sukholitko 
Signed-off-by: Paolo Abeni

net: Correct spelling in net/core

2024-08-26T16:37:23+00:00

Correct spelling in net/core.
As reported by codespell.

Signed-off-by: Simon Horman 
Link: https://patch.msgid.link/20240822-net-spell-v1-13-3a98971ce2d2@kernel.org
Signed-off-by: Jakub Kicinski