kernel/linux.git/net/llc/llc_input.c, branch v7.2-rc5

llc: Add SPDX id lines to some llc source files

2026-05-27T00:26:57+00:00

Most of the lls source files are missing SPDX-License-Identifier lines. Add appropriate IDs to these files, and remove other license info from the header. In once case, leave the existing id line and just remove the license reference text. Signed-off-by: Tim Bird Link: https://patch.msgid.link/20260522225508.24006-1-tim.bird@sony.com Signed-off-by: Jakub Kicinski

net: llc: reset skb->transport_header

2024-12-27T19:23:37+00:00

802.2+LLC+SNAP frames received by napi_complete_done with GRO and DSA have skb->transport_header set two bytes short, or pointing 2 bytes before network_header & skb->data. As snap_rcv expects transport_header to point to SNAP header (OID:PID) after LLC processing advances offset over LLC header (llc_rcv & llc_fixup_skb), code doesn't find a match and packet is dropped. Between napi_complete_done and snap_rcv, transport_header is not used until __netif_receive_skb_core, where originally it was being reset. Commit fda55eca5a33 ("net: introduce skb_transport_header_was_set()") only does so if not set, on the assumption the value was set correctly by GRO (and also on assumption that "network stacks usually reset the transport header anyway"). Afterwards it is moved forward by llc_fixup_skb. Locally generated traffic shows up at __netif_receive_skb_core with no transport_header set and is processed without issue. On a setup with GRO but no DSA, transport_header and network_header are both set to point to skb->data which is also correct. As issue is LLC specific, to avoid impacting non-LLC traffic, and to follow up on original assumption made on previous code change, llc_fixup_skb to reset the offset after skb pull. llc_fixup_skb assumes the LLC header is at skb->data, and by definition SNAP header immediately follows. Fixes: fda55eca5a33 ("net: introduce skb_transport_header_was_set()") Signed-off-by: Antonio Pastor Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20241225010723.2830290-1-antonio.pastor@gmail.com Signed-off-by: Jakub Kicinski

llc: verify mac len before reading mac header

2023-11-02T05:21:32+00:00

LLC reads the mac header with eth_hdr without verifying that the skb has an Ethernet header. Syzbot was able to enter llc_rcv on a tun device. Tun can insert packets without mac len and with user configurable skb->protocol (passing a tun_pi header when not configuring IFF_NO_PI). BUG: KMSAN: uninit-value in llc_station_ac_send_test_r net/llc/llc_station.c:81 [inline] BUG: KMSAN: uninit-value in llc_station_rcv+0x6fb/0x1290 net/llc/llc_station.c:111 llc_station_ac_send_test_r net/llc/llc_station.c:81 [inline] llc_station_rcv+0x6fb/0x1290 net/llc/llc_station.c:111 llc_rcv+0xc5d/0x14a0 net/llc/llc_input.c:218 __netif_receive_skb_one_core net/core/dev.c:5523 [inline] __netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5637 netif_receive_skb_internal net/core/dev.c:5723 [inline] netif_receive_skb+0x58/0x660 net/core/dev.c:5782 tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1555 tun_get_user+0x54c5/0x69c0 drivers/net/tun.c:2002 Add a mac_len test before all three eth_hdr(skb) calls under net/llc. There are further uses in include/net/llc_pdu.h. All these are protected by a test skb->protocol == ETH_P_802_2. Which does not protect against this tun scenario. But the mac_len test added in this patch in llc_fixup_skb will indirectly protect those too. That is called from llc_rcv before any other LLC code. It is tempting to just add a blanket mac_len check in llc_rcv, but not sure whether that could break valid LLC paths that do not assume an Ethernet header. 802.2 LLC may be used on top of non-802.3 protocols in principle. The below referenced commit shows that used to, on top of Token Ring. At least one of the three eth_hdr uses goes back to before the start of git history. But the one that syzbot exercises is introduced in this commit. That commit is old enough (2008), that effectively all stable kernels should receive this. Fixes: f83f1768f833 ("[LLC]: skb allocation size for responses") Reported-by: syzbot+a8c7be6dee0de1b669cc@syzkaller.appspotmail.com Signed-off-by: Willem de Bruijn Link: https://lore.kernel.org/r/20231025234251.3796495-1-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski

llc: Don't drop packet from non-root netns.

2023-07-20T08:46:28+00:00

Now these upper layer protocol handlers can be called from llc_rcv() as sap->rcv_func(), which is registered by llc_sap_open(). * function which is passed to register_8022_client() -> no in-kernel user calls register_8022_client(). * snap_rcv() `- proto->rcvfunc() : registered by register_snap_client() -> aarp_rcv() and atalk_rcv() drop packets from non-root netns * stp_pdu_rcv() `- garp_protos[]->rcv() : registered by stp_proto_register() -> garp_pdu_rcv() and br_stp_rcv() are netns-aware So, we can safely remove the netns restriction in llc_rcv(). Fixes: e730c15519d0 ("[NET]: Make packet reception network namespace safe") Signed-off-by: Kuniyuki Iwashima Signed-off-by: Paolo Abeni

net: llc: kerneldoc fixes

2020-07-14T00:20:39+00:00

Simple fixes which require no deep knowledge of the code. Signed-off-by: Andrew Lunn Signed-off-by: David S. Miller

locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE()

2017-10-25T09:01:08+00:00

Please do not apply this to mainline directly, instead please re-run the coccinelle script shown below and apply its output. For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't harmful, and changing them results in churn. However, for some features, the read/write distinction is critical to correct operation. To distinguish these cases, separate read/write accessors must be used. This patch migrates (most) remaining ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following coccinelle script: ---- // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and // WRITE_ONCE() // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland Signed-off-by: Paul E. McKenney Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar

llc: Fix races between llc2 handler use and (un)registration

2012-08-14T23:52:02+00:00

When registering the handlers, any state they rely on must be completely initialised first. When unregistering, we must wait until they are definitely no longer running. llc_rcv() must also avoid reading the handler pointers again after checking for NULL. Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller

net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules

2011-10-31T23:30:30+00:00

These files are non modular, but need to export symbols using the macros now living in export.h -- call out the include so that things won't break when we remove the implicit presence of module.h from everywhere. Signed-off-by: Paul Gortmaker

llc: Fix length check in llc_fixup_skb().

2011-04-12T01:59:05+00:00

Fixes bugzilla #32872 The LLC stack pretends to support non-linear skbs but there is a direct use of skb_tail_pointer() in llc_fixup_skb(). Use pskb_may_pull() to see if data_size bytes remain and can be accessed linearly in the packet, instead of direct pointer checks. Signed-off-by: David S. Miller

llc: avoid skb_clone() if there is only one handler

2011-02-28T20:28:50+00:00

Signed-off-by: Changli Gao Signed-off-by: David S. Miller