user/sven/linux.git/include/linux/skbuff.h, branch v5.7.14

bpf: Fix up bpf_skb_adjust_room helper's skb csum setting

2020-06-22T07:32:54Z

[ Upstream commit 836e66c218f355ec01ba57671c85abf32961dcea ] Lorenz recently reported: In our TC classifier cls_redirect [0], we use the following sequence of helper calls to decapsulate a GUE (basically IP + UDP + custom header) encapsulated packet: bpf_skb_adjust_room(skb, -encap_len, BPF_ADJ_ROOM_MAC, BPF_F_ADJ_ROOM_FIXED_GSO) bpf_redirect(skb->ifindex, BPF_F_INGRESS) It seems like some checksums of the inner headers are not validated in this case. For example, a TCP SYN packet with invalid TCP checksum is still accepted by the network stack and elicits a SYN ACK. [...] That is, we receive the following packet from the driver: | ETH | IP | UDP | GUE | IP | TCP | skb->ip_summed == CHECKSUM_UNNECESSARY ip_summed is CHECKSUM_UNNECESSARY because our NICs do rx checksum offloading. On this packet we run skb_adjust_room_mac(-encap_len), and get the following: | ETH | IP | TCP | skb->ip_summed == CHECKSUM_UNNECESSARY Note that ip_summed is still CHECKSUM_UNNECESSARY. After bpf_redirect()'ing into the ingress, we end up in tcp_v4_rcv(). There, skb_checksum_init() is turned into a no-op due to CHECKSUM_UNNECESSARY. The bpf_skb_adjust_room() helper is not aware of protocol specifics. Internally, it handles the CHECKSUM_COMPLETE case via skb_postpull_rcsum(), but that does not cover CHECKSUM_UNNECESSARY. In this case skb->csum_level of the original skb prior to bpf_skb_adjust_room() call was 0, that is, covering UDP. Right now there is no way to adjust the skb->csum_level. NICs that have checksum offload disabled (CHECKSUM_NONE) or that support CHECKSUM_COMPLETE are not affected. Use a safe default for CHECKSUM_UNNECESSARY by resetting to CHECKSUM_NONE and add a flag to the helper called BPF_F_ADJ_ROOM_NO_CSUM_RESET that allows users from opting out. Opting out is useful for the case where we don't remove/add full protocol headers, or for the case where a user wants to adjust the csum level manually e.g. through bpf_csum_level() helper that is added in subsequent patch. The bpf_skb_proto_{4_to_6,6_to_4}() for NAT64/46 translation from the BPF bpf_skb_change_proto() helper uses bpf_skb_net_hdr_{push,pop}() pair internally as well but doesn't change layers, only transitions between v4 to v6 and vice versa, therefore no adoption is required there. [0] https://lore.kernel.org/bpf/20200424185556.7358-1-lmb@cloudflare.com/ Fixes: 2be7e212d541 ("bpf: add bpf_skb_adjust_room helper") Reported-by: Lorenz Bauer Reported-by: Alan Maguire Signed-off-by: Daniel Borkmann Signed-off-by: Lorenz Bauer Signed-off-by: Alexei Starovoitov Reviewed-by: Alan Maguire Link: https://lore.kernel.org/bpf/CACAyw9-uU_52esMd1JjuA80fRPHJv5vsSg8GnfW3t_qDU4aVKQ@mail.gmail.com/ Link: https://lore.kernel.org/bpf/11a90472e7cce83e76ddbfce81fdfce7bfc68808.1591108731.git.daniel@iogearbox.net Signed-off-by: Sasha Levin

skbuff.h: Replace zero-length array with flexible-array member

2020-04-18T20:44:56Z

The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva

skbuff.h: Improve the checksum related comments

2020-04-06T17:25:15Z

Fixed the punctuation and some typos. Improved some sentences with minor changes. No change of semantics or code. Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: Randy Dunlap Signed-off-by: Dexuan Cui Signed-off-by: David S. Miller

net: Fix typo of SKB_SGO_CB_OFFSET

2020-03-30T04:53:18Z

The SKB_SGO_CB_OFFSET should be SKB_GSO_CB_OFFSET which means the offset of the GSO in skb cb. This patch fixes the typo. Fixes: 9207f9d45b0a ("net: preserve IP control block during GSO segmentation") Signed-off-by: Cambda Zhu Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2020-03-26T01:58:11Z

Overlapping header include additions in macsec.c A bug fix in 'net' overlapping with the removal of 'version' string in ena_netdev.c Overlapping test additions in selftests Makefile Overlapping PCI ID table adjustments in iwlwifi driver. Signed-off-by: David S. Miller

net: Fix CONFIG_NET_CLS_ACT=n and CONFIG_NFT_FWD_NETDEV={y, m} build

2020-03-25T19:24:33Z

net/netfilter/nft_fwd_netdev.c: In function ‘nft_fwd_netdev_eval’: net/netfilter/nft_fwd_netdev.c:32:10: error: ‘struct sk_buff’ has no member named ‘tc_redirected’ pkt->skb->tc_redirected = 1; ^~ net/netfilter/nft_fwd_netdev.c:33:10: error: ‘struct sk_buff’ has no member named ‘tc_from_ingress’ pkt->skb->tc_from_ingress = 1; ^~ To avoid a direct dependency with tc actions from netfilter, wrap the redirect bits around CONFIG_NET_REDIRECT and move helpers to include/linux/skbuff.h. Turn on this toggle from the ifb driver, the only existing client of these bits in the tree. This patch adds skb_set_redirected() that sets on the redirected bit on the skbuff, it specifies if the packet was redirect from ingress and resets the timestamp (timestamp reset was originally missing in the netfilter bugfix). Fixes: bcfabee1afd99484 ("netfilter: nft_fwd_netdev: allow to redirect to ifb via ingress") Reported-by: noreply@ellerman.id.au Reported-by: Geert Uytterhoeven Signed-off-by: Pablo Neira Ayuso Signed-off-by: David S. Miller

net: datagram: drop 'destructor' argument from several helpers

2020-02-28T20:12:53Z

The only users for such argument are the UDP protocol and the UNIX socket family. We can safely reclaim the accounted memory directly from the UDP code and, after the previous patch, we can do scm stats accounting outside the datagram helpers. Overall this cleans up a bit some datagram-related helpers, and avoids an indirect call per packet in the UDP receive path. v1 -> v2: - call scm_stat_del() only when not peeking - Kirill - fix build issue with CONFIG_INET_ESPINTCP Signed-off-by: Paolo Abeni Reviewed-by: Kirill Tkhai Reviewed-by: Willem de Bruijn Signed-off-by: David S. Miller

skbuff.h: fix all kernel-doc warnings

2020-02-17T03:50:02Z

Fix all kernel-doc warnings in . Fixes these warnings: ../include/linux/skbuff.h:890: warning: Function parameter or member 'list' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member 'dev_scratch' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member 'ip_defrag_offset' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member 'skb_mstamp_ns' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member '__cloned_offset' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member 'head_frag' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member '__pkt_type_offset' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member 'encapsulation' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member 'encap_hdr_csum' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member 'csum_valid' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member '__pkt_vlan_present_offset' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member 'vlan_present' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member 'csum_complete_sw' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member 'csum_level' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member 'inner_protocol_type' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member 'remcsum_offload' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member 'sender_cpu' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member 'reserved_tailroom' not described in 'sk_buff' ../include/linux/skbuff.h:890: warning: Function parameter or member 'inner_ipproto' not described in 'sk_buff' Signed-off-by: Randy Dunlap Signed-off-by: David S. Miller

skbuff: fix a data race in skb_queue_len()

2020-02-06T12:59:10Z

sk_buff.qlen can be accessed concurrently as noticed by KCSAN, BUG: KCSAN: data-race in __skb_try_recv_from_queue / unix_dgram_sendmsg read to 0xffff8a1b1d8a81c0 of 4 bytes by task 5371 on cpu 96: unix_dgram_sendmsg+0x9a9/0xb70 include/linux/skbuff.h:1821 net/unix/af_unix.c:1761 ____sys_sendmsg+0x33e/0x370 ___sys_sendmsg+0xa6/0xf0 __sys_sendmsg+0x69/0xf0 __x64_sys_sendmsg+0x51/0x70 do_syscall_64+0x91/0xb47 entry_SYSCALL_64_after_hwframe+0x49/0xbe write to 0xffff8a1b1d8a81c0 of 4 bytes by task 1 on cpu 99: __skb_try_recv_from_queue+0x327/0x410 include/linux/skbuff.h:2029 __skb_try_recv_datagram+0xbe/0x220 unix_dgram_recvmsg+0xee/0x850 ____sys_recvmsg+0x1fb/0x210 ___sys_recvmsg+0xa2/0xf0 __sys_recvmsg+0x66/0xf0 __x64_sys_recvmsg+0x51/0x70 do_syscall_64+0x91/0xb47 entry_SYSCALL_64_after_hwframe+0x49/0xbe Since only the read is operating as lockless, it could introduce a logic bug in unix_recvq_full() due to the load tearing. Fix it by adding a lockless variant of skb_queue_len() and unix_recvq_full() where READ_ONCE() is on the read while WRITE_ONCE() is on the write similar to the commit d7d16a89350a ("net: add skb_queue_empty_lockless()"). Signed-off-by: Qian Cai Signed-off-by: David S. Miller

net: Support GRO/GSO fraglist chaining.

2020-01-27T10:00:21Z

This patch adds the core functions to chain/unchain GSO skbs at the frag_list pointer. This also adds a new GSO type SKB_GSO_FRAGLIST and a is_flist flag to napi_gro_cb which indicates that this flow will be GROed by fraglist chaining. Signed-off-by: Steffen Klassert Reviewed-by: Willem de Bruijn Signed-off-by: David S. Miller