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2022-10-11treewide: use get_random_{u8,u16}() when possible, part 1Jason A. Donenfeld1-1/+1
Rather than truncate a 32-bit value to a 16-bit value or an 8-bit value, simply use the get_random_{u8,u16}() functions, which are faster than wasting the additional bytes from a 32-bit value. This was done mechanically with this coccinelle script: @@ expression E; identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; typedef u16; typedef __be16; typedef __le16; typedef u8; @@ ( - (get_random_u32() & 0xffff) + get_random_u16() | - (get_random_u32() & 0xff) + get_random_u8() | - (get_random_u32() % 65536) + get_random_u16() | - (get_random_u32() % 256) + get_random_u8() | - (get_random_u32() >> 16) + get_random_u16() | - (get_random_u32() >> 24) + get_random_u8() | - (u16)get_random_u32() + get_random_u16() | - (u8)get_random_u32() + get_random_u8() | - (__be16)get_random_u32() + (__be16)get_random_u16() | - (__le16)get_random_u32() + (__le16)get_random_u16() | - prandom_u32_max(65536) + get_random_u16() | - prandom_u32_max(256) + get_random_u8() | - E->inet_id = get_random_u32() + E->inet_id = get_random_u16() ) @@ identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; typedef u16; identifier v; @@ - u16 v = get_random_u32(); + u16 v = get_random_u16(); @@ identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; typedef u8; identifier v; @@ - u8 v = get_random_u32(); + u8 v = get_random_u8(); @@ identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; typedef u16; u16 v; @@ - v = get_random_u32(); + v = get_random_u16(); @@ identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; typedef u8; u8 v; @@ - v = get_random_u32(); + v = get_random_u8(); // Find a potential literal @literal_mask@ expression LITERAL; type T; identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; position p; @@ ((T)get_random_u32()@p & (LITERAL)) // Examine limits @script:python add_one@ literal << literal_mask.LITERAL; RESULT; @@ value = None if literal.startswith('0x'): value = int(literal, 16) elif literal[0] in '123456789': value = int(literal, 10) if value is None: print("I don't know how to handle %s" % (literal)) cocci.include_match(False) elif value < 256: coccinelle.RESULT = cocci.make_ident("get_random_u8") elif value < 65536: coccinelle.RESULT = cocci.make_ident("get_random_u16") else: print("Skipping large mask of %s" % (literal)) cocci.include_match(False) // Replace the literal mask with the calculated result. @plus_one@ expression literal_mask.LITERAL; position literal_mask.p; identifier add_one.RESULT; identifier FUNC; @@ - (FUNC()@p & (LITERAL)) + (RESULT() & LITERAL) Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Yury Norov <yury.norov@gmail.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> # for sch_cake Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-09-28net: shrink struct ubuf_infoPavel Begunkov1-1/+1
We can benefit from a smaller struct ubuf_info, so leave only mandatory fields and let users to decide how they want to extend it. Convert MSG_ZEROCOPY to struct ubuf_info_msgzc and remove duplicated fields. This reduces the size from 48 bytes to just 16. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-08-30net: unify alloclen calculation for paged requestsPavel Begunkov1-4/+1
Consolidate alloclen and pagedlen calculation for zerocopy and normal paged requests. The current non-zerocopy paged version can a bit overallocate and unnecessary copy a small chunk of data into the linear part. Cc: Willem de Bruijn <willemb@google.com> Link: https://lore.kernel.org/netdev/CA+FuTSf0+cJ9_N_xrHmCGX_KoVCWcE0YQBdtgEkzGvcLMSv7Qw@mail.gmail.com/ Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/b0e4edb7b91f171c7119891d3c61040b8c56596e.1661428921.git.asml.silence@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-08-24net: Fix data-races around sysctl_[rw]mem_(max|default).Kuniyuki Iwashima1-1/+1
While reading sysctl_[rw]mem_(max|default), they can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-07-19Merge branch 'io_uring-zerocopy-send' of git://git.kernel.org/pub/scm/linux/kernel/git/kuba/linuxJakub Kicinski1-14/+36
Pavel Begunkov says: ==================== io_uring zerocopy send The patchset implements io_uring zerocopy send. It works with both registered and normal buffers, mixing is allowed but not recommended. Apart from usual request completions, just as with MSG_ZEROCOPY, io_uring separately notifies the userspace when buffers are freed and can be reused (see API design below), which is delivered into io_uring's Completion Queue. Those "buffer-free" notifications are not necessarily per request, but the userspace has control over it and should explicitly attaching a number of requests to a single notification. The series also adds some internal optimisations when used with registered buffers like removing page referencing. From the kernel networking perspective there are two main changes. The first one is passing ubuf_info into the network layer from io_uring (inside of an in kernel struct msghdr). This allows extra optimisations, e.g. ubuf_info caching on the io_uring side, but also helps to avoid cross-referencing and synchronisation problems. The second part is an optional optimisation removing page referencing for requests with registered buffers. Benchmarking UDP with an optimised version of the selftest (see [1]), which sends a bunch of requests, waits for completions and repeats. "+ flush" column posts one additional "buffer-free" notification per request, and just "zc" doesn't post buffer notifications at all. NIC (requests / second): IO size | non-zc | zc | zc + flush 4000 | 495134 | 606420 (+22%) | 558971 (+12%) 1500 | 551808 | 577116 (+4.5%) | 565803 (+2.5%) 1000 | 584677 | 592088 (+1.2%) | 560885 (-4%) 600 | 596292 | 598550 (+0.4%) | 555366 (-6.7%) dummy (requests / second): IO size | non-zc | zc | zc + flush 8000 | 1299916 | 2396600 (+84%) | 2224219 (+71%) 4000 | 1869230 | 2344146 (+25%) | 2170069 (+16%) 1200 | 2071617 | 2361960 (+14%) | 2203052 (+6%) 600 | 2106794 | 2381527 (+13%) | 2195295 (+4%) Previously it also brought a massive performance speedup compared to the msg_zerocopy tool (see [3]), which is probably not super interesting. There is also an additional bunch of refcounting optimisations that was omitted from the series for simplicity and as they don't change the picture drastically, they will be sent as follow up, as well as flushing optimisations closing the performance gap b/w two last columns. For TCP on localhost (with hacks enabling localhost zerocopy) and including additional overhead for receive: IO size | non-zc | zc 1200 | 4174 | 4148 4096 | 7597 | 11228 Using a real NIC 1200 bytes, zc is worse than non-zc ~5-10%, maybe the omitted optimisations will somewhat help, should look better for 4000, but couldn't test properly because of setup problems. Links: liburing (benchmark + tests): [1] https://github.com/isilence/liburing/tree/zc_v4 kernel repo: [2] https://github.com/isilence/linux/tree/zc_v4 RFC v1: [3] https://lore.kernel.org/io-uring/cover.1638282789.git.asml.silence@gmail.com/ RFC v2: https://lore.kernel.org/io-uring/cover.1640029579.git.asml.silence@gmail.com/ Net patches based: git@github.com:isilence/linux.git zc_v4-net-base or https://github.com/isilence/linux/tree/zc_v4-net-base API design overview: The series introduces an io_uring concept of notifactors. From the userspace perspective it's an entity to which it can bind one or more requests and then requesting to flush it. Flushing a notifier makes it impossible to attach new requests to it, and instructs the notifier to post a completion once all requests attached to it are completed and the kernel doesn't need the buffers anymore. Notifications are stored in notification slots, which should be registered as an array in io_uring. Each slot stores only one notifier at any particular moment. Flushing removes it from the slot and the slot automatically replaces it with a new notifier. All operations with notifiers are done by specifying an index of a slot it's currently in. When registering a notification the userspace specifies a u64 tag for each slot, which will be copied in notification completion entries as cqe::user_data. cqe::res is 0 and cqe::flags is equal to wrap around u32 sequence number counting notifiers of a slot. ==================== Link: https://lore.kernel.org/r/cover.1657643355.git.asml.silence@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-07-19ipv4/udp: support externally provided ubufsPavel Begunkov1-13/+31
Teach ipv4/udp how to use external ubuf_info provided in msghdr and also prepare it for managed frags by sprinkling skb_zcopy_downgrade_managed() when it could mix managed and not managed frags. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-07-18ipv4: avoid partial copy for zcPavel Begunkov1-2/+6
Even when zerocopy transmission is requested and possible, __ip_append_data() will still copy a small chunk of data just because it allocated some extra linear space (e.g. 148 bytes). It wastes CPU cycles on copy and iter manipulations and also misalignes potentially aligned data. Avoid such copies. And as a bonus we can allocate smaller skb. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-07-11net: Find dst with sk's xfrm policy not ctl_sksewookseo1-1/+1
If we set XFRM security policy by calling setsockopt with option IPV6_XFRM_POLICY, the policy will be stored in 'sock_policy' in 'sock' struct. However tcp_v6_send_response doesn't look up dst_entry with the actual socket but looks up with tcp control socket. This may cause a problem that a RST packet is sent without ESP encryption & peer's TCP socket can't receive it. This patch will make the function look up dest_entry with actual socket, if the socket has XFRM policy(sock_policy), so that the TCP response packet via this function can be encrypted, & aligned on the encrypted TCP socket. Tested: We encountered this problem when a TCP socket which is encrypted in ESP transport mode encryption, receives challenge ACK at SYN_SENT state. After receiving challenge ACK, TCP needs to send RST to establish the socket at next SYN try. But the RST was not encrypted & peer TCP socket still remains on ESTABLISHED state. So we verified this with test step as below. [Test step] 1. Making a TCP state mismatch between client(IDLE) & server(ESTABLISHED). 2. Client tries a new connection on the same TCP ports(src & dst). 3. Server will return challenge ACK instead of SYN,ACK. 4. Client will send RST to server to clear the SOCKET. 5. Client will retransmit SYN to server on the same TCP ports. [Expected result] The TCP connection should be established. Cc: Maciej Żenczykowski <maze@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: Sehee Lee <seheele@google.com> Signed-off-by: Sewook Seo <sewookseo@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-06-24net: helper function skb_len_addRichard Gobert1-6/+2
Move the len fields manipulation in the skbs to a helper function. There is a comment specifically requesting this and there are several other areas in the code displaying the same pattern which can be refactored. This improves code readability. Signed-off-by: Richard Gobert <richardbgobert@gmail.com> Link: https://lore.kernel.org/r/20220622160853.GA6478@debian Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-03-03net: Set skb->mono_delivery_time and clear it after sch_handle_ingress()Martin KaFai Lau1-2/+1
The previous patches handled the delivery_time before sch_handle_ingress(). This patch can now set the skb->mono_delivery_time to flag the skb->tstamp is used as the mono delivery_time (EDT) instead of the (rcv) timestamp and also clear it with skb_clear_delivery_time() after sch_handle_ingress(). This will make the bpf_redirect_*() to keep the mono delivery_time and used by a qdisc (fq) of the egress-ing interface. A latter patch will postpone the skb_clear_delivery_time() until the stack learns that the skb is being delivered locally and that will make other kernel forwarding paths (ip[6]_forward) able to keep the delivery_time also. Thus, like the previous patches on using the skb->mono_delivery_time bit, calling skb_clear_delivery_time() is not limited within the CONFIG_NET_INGRESS to avoid too many code churns among this set. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-03-03net: Add skb->mono_delivery_time to distinguish mono delivery_time from (rcv) timestampMartin KaFai Lau1-2/+5
skb->tstamp was first used as the (rcv) timestamp. The major usage is to report it to the user (e.g. SO_TIMESTAMP). Later, skb->tstamp is also set as the (future) delivery_time (e.g. EDT in TCP) during egress and used by the qdisc (e.g. sch_fq) to make decision on when the skb can be passed to the dev. Currently, there is no way to tell skb->tstamp having the (rcv) timestamp or the delivery_time, so it is always reset to 0 whenever forwarded between egress and ingress. While it makes sense to always clear the (rcv) timestamp in skb->tstamp to avoid confusing sch_fq that expects the delivery_time, it is a performance issue [0] to clear the delivery_time if the skb finally egress to a fq@phy-dev. For example, when forwarding from egress to ingress and then finally back to egress: tcp-sender => veth@netns => veth@hostns => fq@eth0@hostns ^ ^ reset rest This patch adds one bit skb->mono_delivery_time to flag the skb->tstamp is storing the mono delivery_time (EDT) instead of the (rcv) timestamp. The current use case is to keep the TCP mono delivery_time (EDT) and to be used with sch_fq. A latter patch will also allow tc-bpf@ingress to read and change the mono delivery_time. In the future, another bit (e.g. skb->user_delivery_time) can be added for the SCM_TXTIME where the clock base is tracked by sk->sk_clockid. [ This patch is a prep work. The following patches will get the other parts of the stack ready first. Then another patch after that will finally set the skb->mono_delivery_time. ] skb_set_delivery_time() function is added. It is used by the tcp_output.c and during ip[6] fragmentation to assign the delivery_time to the skb->tstamp and also set the skb->mono_delivery_time. A note on the change in ip_send_unicast_reply() in ip_output.c. It is only used by TCP to send reset/ack out of a ctl_sk. Like the new skb_set_delivery_time(), this patch sets the skb->mono_delivery_time to 0 for now as a place holder. It will be enabled in a latter patch. A similar case in tcp_ipv6 can be done with skb_set_delivery_time() in tcp_v6_send_response(). [0] (slide 22): https://linuxplumbersconf.org/event/11/contributions/953/attachments/867/1658/LPC_2021_BPF_Datapath_Extensions.pdf Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-26net: ip: add skb drop reasons for ip egress pathMenglong Dong1-4/+4
Replace kfree_skb() which is used in the packet egress path of IP layer with kfree_skb_reason(). Functions that are involved include: __ip_queue_xmit() ip_finish_output() ip_mc_finish_output() ip6_output() ip6_finish_output() ip6_finish_output2() Following new drop reasons are introduced: SKB_DROP_REASON_IP_OUTNOROUTES SKB_DROP_REASON_BPF_CGROUP_EGRESS SKB_DROP_REASON_IPV6DISABLED SKB_DROP_REASON_NEIGH_CREATEFAIL Reviewed-by: Mengen Sun <mengensun@tencent.com> Reviewed-by: Hao Peng <flyingpeng@tencent.com> Signed-off-by: Menglong Dong <imagedong@tencent.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-24Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-1/+1
tools/testing/selftests/net/mptcp/mptcp_join.sh 34aa6e3bccd8 ("selftests: mptcp: add ip mptcp wrappers") 857898eb4b28 ("selftests: mptcp: add missing join check") 6ef84b1517e0 ("selftests: mptcp: more robust signal race test") https://lore.kernel.org/all/20220221131842.468893-1-broonie@kernel.org/ drivers/net/ethernet/mellanox/mlx5/core/en/tc/act/act.h drivers/net/ethernet/mellanox/mlx5/core/en/tc/act/ct.c fb7e76ea3f3b6 ("net/mlx5e: TC, Skip redundant ct clear actions") c63741b426e11 ("net/mlx5e: Fix MPLSoUDP encap to use MPLS action information") 09bf97923224f ("net/mlx5e: TC, Move pedit_headers_action to parse_attr") 84ba8062e383 ("net/mlx5e: Test CT and SAMPLE on flow attr") efe6f961cd2e ("net/mlx5e: CT, Don't set flow flag CT for ct clear flow") 3b49a7edec1d ("net/mlx5e: TC, Reject rules with multiple CT actions") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-18net-timestamp: convert sk->sk_tskey to atomic_tEric Dumazet1-1/+1
UDP sendmsg() can be lockless, this is causing all kinds of data races. This patch converts sk->sk_tskey to remove one of these races. BUG: KCSAN: data-race in __ip_append_data / __ip_append_data read to 0xffff8881035d4b6c of 4 bytes by task 8877 on cpu 1: __ip_append_data+0x1c1/0x1de0 net/ipv4/ip_output.c:994 ip_make_skb+0x13f/0x2d0 net/ipv4/ip_output.c:1636 udp_sendmsg+0x12bd/0x14c0 net/ipv4/udp.c:1249 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:819 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg net/socket.c:725 [inline] ____sys_sendmsg+0x39a/0x510 net/socket.c:2413 ___sys_sendmsg net/socket.c:2467 [inline] __sys_sendmmsg+0x267/0x4c0 net/socket.c:2553 __do_sys_sendmmsg net/socket.c:2582 [inline] __se_sys_sendmmsg net/socket.c:2579 [inline] __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2579 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae write to 0xffff8881035d4b6c of 4 bytes by task 8880 on cpu 0: __ip_append_data+0x1d8/0x1de0 net/ipv4/ip_output.c:994 ip_make_skb+0x13f/0x2d0 net/ipv4/ip_output.c:1636 udp_sendmsg+0x12bd/0x14c0 net/ipv4/udp.c:1249 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:819 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg net/socket.c:725 [inline] ____sys_sendmsg+0x39a/0x510 net/socket.c:2413 ___sys_sendmsg net/socket.c:2467 [inline] __sys_sendmmsg+0x267/0x4c0 net/socket.c:2553 __do_sys_sendmmsg net/socket.c:2582 [inline] __se_sys_sendmmsg net/socket.c:2579 [inline] __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2579 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0x0000054d -> 0x0000054e Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 8880 Comm: syz-executor.5 Not tainted 5.17.0-rc2-syzkaller-00167-gdcb85f85fa6f-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: 09c2d251b707 ("net-timestamp: add key to disambiguate concurrent datagrams") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-01-29ipv4: drop fragmentation code from ip_options_build()Jakub Kicinski1-3/+3
Since v2.5.44 and addition of ip_options_fragment() ip_options_build() does not render headers for fragments directly. @is_frag is always 0. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-01-27ipv4: tcp: send zero IPID in SYNACK messagesEric Dumazet1-2/+9
In commit 431280eebed9 ("ipv4: tcp: send zero IPID for RST and ACK sent in SYN-RECV and TIME-WAIT state") we took care of some ctl packets sent by TCP. It turns out we need to use a similar strategy for SYNACK packets. By default, they carry IP_DF and IPID==0, but there are ways to ask them to use the hashed IP ident generator and thus be used to build off-path attacks. (Ref: Off-Path TCP Exploits of the Mixed IPID Assignment) One of this way is to force (before listener is started) echo 1 >/proc/sys/net/ipv4/ip_no_pmtu_disc Another way is using forged ICMP ICMP_FRAG_NEEDED with a very small MTU (like 68) to force a false return from ip_dont_fragment() In this patch, ip_build_and_send_pkt() uses the following heuristics. 1) Most SYNACK packets are smaller than IPV4_MIN_MTU and therefore can use IP_DF regardless of the listener or route pmtu setting. 2) In case the SYNACK packet is bigger than IPV4_MIN_MTU, we use prandom_u32() generator instead of the IPv4 hashed ident one. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Ray Che <xijiache@gmail.com> Reviewed-by: David Ahern <dsahern@kernel.org> Cc: Geoff Alexander <alexandg@cs.unm.edu> Cc: Willy Tarreau <w@1wt.eu> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-01-24ipv4: fix ip option filtering for locally generated fragmentsJakub Kicinski1-3/+12
During IP fragmentation we sanitize IP options. This means overwriting options which should not be copied with NOPs. Only the first fragment has the original, full options. ip_fraglist_prepare() copies the IP header and options from previous fragment to the next one. Commit 19c3401a917b ("net: ipv4: place control buffer handling away from fragmentation iterators") moved sanitizing options before ip_fraglist_prepare() which means options are sanitized and then overwritten again with the old values. Fixing this is not enough, however, nor did the sanitization work prior to aforementioned commit. ip_options_fragment() (which does the sanitization) uses ipcb->opt.optlen for the length of the options. ipcb->opt of fragments is not populated (it's 0), only the head skb has the state properly built. So even when called at the right time ip_options_fragment() does nothing. This seems to date back all the way to v2.5.44 when the fast path for pre-fragmented skbs had been introduced. Prior to that ip_options_build() would have been called for every fragment (in fact ever since v2.5.44 the fragmentation handing in ip_options_build() has been dead code, I'll clean it up in -next). In the original patch (see Link) caixf mentions fixing the handling for fragments other than the second one, but I'm not sure how _any_ fragment could have had their options sanitized with the code as it stood. Tested with python (MTU on lo lowered to 1000 to force fragmentation): import socket s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) s.setsockopt(socket.IPPROTO_IP, socket.IP_OPTIONS, bytearray([7,4,5,192, 20|0x80,4,1,0])) s.sendto(b'1'*2000, ('127.0.0.1', 1234)) Before: IP (tos 0x0, ttl 64, id 1053, offset 0, flags [+], proto UDP (17), length 996, options (RR [bad length 4] [bad ptr 5] 192.148.4.1,,RA value 256)) localhost.36500 > localhost.search-agent: UDP, length 2000 IP (tos 0x0, ttl 64, id 1053, offset 968, flags [+], proto UDP (17), length 996, options (RR [bad length 4] [bad ptr 5] 192.148.4.1,,RA value 256)) localhost > localhost: udp IP (tos 0x0, ttl 64, id 1053, offset 1936, flags [none], proto UDP (17), length 100, options (RR [bad length 4] [bad ptr 5] 192.148.4.1,,RA value 256)) localhost > localhost: udp After: IP (tos 0x0, ttl 96, id 42549, offset 0, flags [+], proto UDP (17), length 996, options (RR [bad length 4] [bad ptr 5] 192.148.4.1,,RA value 256)) localhost.51607 > localhost.search-agent: UDP, bad length 2000 > 960 IP (tos 0x0, ttl 96, id 42549, offset 968, flags [+], proto UDP (17), length 996, options (NOP,NOP,NOP,NOP,RA value 256)) localhost > localhost: udp IP (tos 0x0, ttl 96, id 42549, offset 1936, flags [none], proto UDP (17), length 100, options (NOP,NOP,NOP,NOP,RA value 256)) localhost > localhost: udp RA (20 | 0x80) is now copied as expected, RR (7) is "NOPed out". Link: https://lore.kernel.org/netdev/20220107080559.122713-1-ooppublic@163.com/ Fixes: 19c3401a917b ("net: ipv4: place control buffer handling away from fragmentation iterators") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: caixf <ooppublic@163.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-14ipv4: Remove duplicate assignmentsluo penghao1-1/+0
there is a same action when the variable is initialized Reported-by: Zeal Robot <zealci@zte.com.cn> Signed-off-by: luo penghao <luo.penghao@zte.com.cn> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-30net: ipv4: Fix the warning for dereferenceYajun Deng1-1/+3
Add a if statements to avoid the warning. Dan Carpenter report: The patch faf482ca196a: "net: ipv4: Move ip_options_fragment() out of loop" from Aug 23, 2021, leads to the following Smatch complaint: net/ipv4/ip_output.c:833 ip_do_fragment() warn: variable dereferenced before check 'iter.frag' (see line 828) Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Fixes: faf482ca196a ("net: ipv4: Move ip_options_fragment() out of loop") Link: https://lore.kernel.org/netdev/20210830073802.GR7722@kadam/T/#t Signed-off-by: Yajun Deng <yajun.deng@linux.dev> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-24net: ipv4: Move ip_options_fragment() out of loopYajun Deng1-15/+4
The ip_options_fragment() only called when iter->offset is equal to zero, so move it out of loop, and inline 'Copy the flags to each fragment.' As also, remove the unused parameter in ip_frag_ipcb(). Signed-off-by: Yajun Deng <yajun.deng@linux.dev> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-03ipv4: use skb_expand_head in ip_finish_output2Vasily Averin1-11/+2
Unlike skb_realloc_headroom, new helper skb_expand_head does not allocate a new skb if possible. Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-07-26ipv4: ip_output.c: Fix out-of-bounds warning in ip_copy_addrs()Gustavo A. R. Silva1-2/+3
Fix the following out-of-bounds warning: In function 'ip_copy_addrs', inlined from '__ip_queue_xmit' at net/ipv4/ip_output.c:517:2: net/ipv4/ip_output.c:449:2: warning: 'memcpy' offset [40, 43] from the object at 'fl' is out of the bounds of referenced subobject 'saddr' with type 'unsigned int' at offset 36 [-Warray-bounds] 449 | memcpy(&iph->saddr, &fl4->saddr, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 450 | sizeof(fl4->saddr) + sizeof(fl4->daddr)); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The problem is that the original code is trying to copy data into a couple of struct members adjacent to each other in a single call to memcpy(). This causes a legitimate compiler warning because memcpy() overruns the length of &iph->saddr and &fl4->saddr. As these are just a couple of struct members, fix this by using direct assignments, instead of memcpy(). This helps with the ongoing efforts to globally enable -Warray-bounds and get us closer to being able to tighten the FORTIFY_SOURCE routines on memcpy(). Link: https://github.com/KSPP/linux/issues/109 Reported-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/lkml/d5ae2e65-1f18-2577-246f-bada7eee6ccd@intel.com/ Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-06-24net: ip: avoid OOM kills with large UDP sends over loopbackJakub Kicinski1-14/+18
Dave observed number of machines hitting OOM on the UDP send path. The workload seems to be sending large UDP packets over loopback. Since loopback has MTU of 64k kernel will try to allocate an skb with up to 64k of head space. This has a good chance of failing under memory pressure. What's worse if the message length is <32k the allocation may trigger an OOM killer. This is entirely avoidable, we can use an skb with page frags. af_unix solves a similar problem by limiting the head length to SKB_MAX_ALLOC. This seems like a good and simple approach. It means that UDP messages > 16kB will now use fragments if underlying device supports SG, if extra allocator pressure causes regressions in real workloads we can switch to trying the large allocation first and falling back. v4: pre-calculate all the additions to alloclen so we can be sure it won't go over order-2 Reported-by: Dave Jones <dsj@fb.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-28ipv4: ip_output.c: Couple of typo fixesBhaskar Chowdhury1-2/+2
s/readibility/readability/ s/insufficent/insufficient/ Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-02-03net: use indirect call helpers for dst_outputBrian Vazquez1-0/+1
This patch avoids the indirect call for the common case: ip6_output and ip_output Signed-off-by: Brian Vazquez <brianvv@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-01-08Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-1/+1
Trivial conflict in CAN on file rename. Conflicts: drivers/net/can/m_can/tcan4x5x-core.c Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-01-07skbuff: Rename skb_zcopy_{get|put} to net_zcopy_{get|put}Jonathan Lemon1-1/+1
Unlike the rest of the skb_zcopy_ functions, these routines operate on a 'struct ubuf', not a skb. Remove the 'skb_' prefix from the naming to make things clearer. Suggested-by: Willem de Bruijn <willemdebruijn.kernel@gmail.com> Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-01-07skbuff: rename sock_zerocopy_* to msg_zerocopy_*Jonathan Lemon1-1/+1
At Willem's suggestion, rename the sock_zerocopy_* functions so that they match the MSG_ZEROCOPY flag, which makes it clear they are specific to this zerocopy implementation. Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-01-07skbuff: Call sock_zerocopy_put_abort from skb_zcopy_put_abortJonathan Lemon1-2/+1
The sock_zerocopy_put_abort function contains logic which is specific to the current zerocopy implementation. Add a wrapper which checks the callback and dispatches apppropriately. Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-01-07net: ip: always refragment ip defragmented packetsFlorian Westphal1-1/+1
Conntrack reassembly records the largest fragment size seen in IPCB. However, when this gets forwarded/transmitted, fragmentation will only be forced if one of the fragmented packets had the DF bit set. In that case, a flag in IPCB will force fragmentation even if the MTU is large enough. This should work fine, but this breaks with ip tunnels. Consider client that sends a UDP datagram of size X to another host. The client fragments the datagram, so two packets, of size y and z, are sent. DF bit is not set on any of these packets. Middlebox netfilter reassembles those packets back to single size-X packet, before routing decision. packet-size-vs-mtu checks in ip_forward are irrelevant, because DF bit isn't set. At output time, ip refragmentation is skipped as well because x is still smaller than the mtu of the output device. If ttransmit device is an ip tunnel, the packet size increases to x+overhead. Also, tunnel might be configured to force DF bit on outer header. In this case, packet will be dropped (exceeds MTU) and an ICMP error is generated back to sender. But sender already respects the announced MTU, all the packets that it sent did fit the announced mtu. Force refragmentation as per original sizes unconditionally so ip tunnel will encapsulate the fragments instead. The only other solution I see is to place ip refragmentation in the ip_tunnel code to handle this case. Fixes: d6b915e29f4ad ("ip_fragment: don't forward defragmented DF packet") Reported-by: Christian Perle <christian.perle@secunet.com> Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-11-23lsm,selinux: pass flowi_common instead of flowi to the LSM hooksPaul Moore1-1/+1
As pointed out by Herbert in a recent related patch, the LSM hooks do not have the necessary address family information to use the flowi struct safely. As none of the LSMs currently use any of the protocol specific flowi information, replace the flowi pointers with pointers to the address family independent flowi_common struct. Reported-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-10-15Merge tag 'net-next-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextLinus Torvalds1-5/+6
Pull networking updates from Jakub Kicinski: - Add redirect_neigh() BPF packet redirect helper, allowing to limit stack traversal in common container configs and improving TCP back-pressure. Daniel reports ~10Gbps => ~15Gbps single stream TCP performance gain. - Expand netlink policy support and improve policy export to user space. (Ge)netlink core performs request validation according to declared policies. Expand the expressiveness of those policies (min/max length and bitmasks). Allow dumping policies for particular commands. This is used for feature discovery by user space (instead of kernel version parsing or trial and error). - Support IGMPv3/MLDv2 multicast listener discovery protocols in bridge. - Allow more than 255 IPv4 multicast interfaces. - Add support for Type of Service (ToS) reflection in SYN/SYN-ACK packets of TCPv6. - In Multi-patch TCP (MPTCP) support concurrent transmission of data on multiple subflows in a load balancing scenario. Enhance advertising addresses via the RM_ADDR/ADD_ADDR options. - Support SMC-Dv2 version of SMC, which enables multi-subnet deployments. - Allow more calls to same peer in RxRPC. - Support two new Controller Area Network (CAN) protocols - CAN-FD and ISO 15765-2:2016. - Add xfrm/IPsec compat layer, solving the 32bit user space on 64bit kernel problem. - Add TC actions for implementing MPLS L2 VPNs. - Improve nexthop code - e.g. handle various corner cases when nexthop objects are removed from groups better, skip unnecessary notifications and make it easier to offload nexthops into HW by converting to a blocking notifier. - Support adding and consuming TCP header options by BPF programs, opening the doors for easy experimental and deployment-specific TCP option use. - Reorganize TCP congestion control (CC) initialization to simplify life of TCP CC implemented in BPF. - Add support for shipping BPF programs with the kernel and loading them early on boot via the User Mode Driver mechanism, hence reusing all the user space infra we have. - Support sleepable BPF programs, initially targeting LSM and tracing. - Add bpf_d_path() helper for returning full path for given 'struct path'. - Make bpf_tail_call compatible with bpf-to-bpf calls. - Allow BPF programs to call map_update_elem on sockmaps. - Add BPF Type Format (BTF) support for type and enum discovery, as well as support for using BTF within the kernel itself (current use is for pretty printing structures). - Support listing and getting information about bpf_links via the bpf syscall. - Enhance kernel interfaces around NIC firmware update. Allow specifying overwrite mask to control if settings etc. are reset during update; report expected max time operation may take to users; support firmware activation without machine reboot incl. limits of how much impact reset may have (e.g. dropping link or not). - Extend ethtool configuration interface to report IEEE-standard counters, to limit the need for per-vendor logic in user space. - Adopt or extend devlink use for debug, monitoring, fw update in many drivers (dsa loop, ice, ionic, sja1105, qed, mlxsw, mv88e6xxx, dpaa2-eth). - In mlxsw expose critical and emergency SFP module temperature alarms. Refactor port buffer handling to make the defaults more suitable and support setting these values explicitly via the DCBNL interface. - Add XDP support for Intel's igb driver. - Support offloading TC flower classification and filtering rules to mscc_ocelot switches. - Add PTP support for Marvell Octeontx2 and PP2.2 hardware, as well as fixed interval period pulse generator and one-step timestamping in dpaa-eth. - Add support for various auth offloads in WiFi APs, e.g. SAE (WPA3) offload. - Add Lynx PHY/PCS MDIO module, and convert various drivers which have this HW to use it. Convert mvpp2 to split PCS. - Support Marvell Prestera 98DX3255 24-port switch ASICs, as well as 7-port Mediatek MT7531 IP. - Add initial support for QCA6390 and IPQ6018 in ath11k WiFi driver, and wcn3680 support in wcn36xx. - Improve performance for packets which don't require much offloads on recent Mellanox NICs by 20% by making multiple packets share a descriptor entry. - Move chelsio inline crypto drivers (for TLS and IPsec) from the crypto subtree to drivers/net. Move MDIO drivers out of the phy directory. - Clean up a lot of W=1 warnings, reportedly the actively developed subsections of networking drivers should now build W=1 warning free. - Make sure drivers don't use in_interrupt() to dynamically adapt their code. Convert tasklets to use new tasklet_setup API (sadly this conversion is not yet complete). * tag 'net-next-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2583 commits) Revert "bpfilter: Fix build error with CONFIG_BPFILTER_UMH" net, sockmap: Don't call bpf_prog_put() on NULL pointer bpf, selftest: Fix flaky tcp_hdr_options test when adding addr to lo bpf, sockmap: Add locking annotations to iterator netfilter: nftables: allow re-computing sctp CRC-32C in 'payload' statements net: fix pos incrementment in ipv6_route_seq_next net/smc: fix invalid return code in smcd_new_buf_create() net/smc: fix valid DMBE buffer sizes net/smc: fix use-after-free of delayed events bpfilter: Fix build error with CONFIG_BPFILTER_UMH cxgb4/ch_ipsec: Replace the module name to ch_ipsec from chcr net: sched: Fix suspicious RCU usage while accessing tcf_tunnel_info bpf: Fix register equivalence tracking. rxrpc: Fix loss of final ack on shutdown rxrpc: Fix bundle counting for exclusive connections netfilter: restore NF_INET_NUMHOOKS ibmveth: Identify ingress large send packets. ibmveth: Switch order of ibmveth_helper calls. cxgb4: handle 4-tuple PEDIT to NAT mode translation selftests: Add VRF route leaking tests ...
2020-10-12Merge branch 'work.csum_and_copy' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfsLinus Torvalds1-3/+3
Pull copy_and_csum cleanups from Al Viro: "Saner calling conventions for csum_and_copy_..._user() and friends" [ Removing 800+ lines of code and cleaning stuff up is good - Linus ] * 'work.csum_and_copy' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: ppc: propagate the calling conventions change down to csum_partial_copy_generic() amd64: switch csum_partial_copy_generic() to new calling conventions sparc64: propagate the calling convention changes down to __csum_partial_copy_...() xtensa: propagate the calling conventions change down into csum_partial_copy_generic() mips: propagate the calling convention change down into __csum_partial_copy_..._user() mips: __csum_partial_copy_kernel() has no users left mips: csum_and_copy_{to,from}_user() are never called under KERNEL_DS sparc32: propagate the calling conventions change down to __csum_partial_copy_sparc_generic() i386: propagate the calling conventions change down to csum_partial_copy_generic() sh: propage the calling conventions change down to csum_partial_copy_generic() m68k: get rid of zeroing destination on error in csum_and_copy_from_user() arm: propagate the calling convention changes down to csum_partial_copy_from_user() alpha: propagate the calling convention changes down to csum_partial_copy.c helpers saner calling conventions for csum_and_copy_..._user() csum_and_copy_..._user(): pass 0xffffffff instead of 0 as initial sum csum_partial_copy_nocheck(): drop the last argument unify generic instances of csum_partial_copy_nocheck() icmp_push_reply(): reorder adding the checksum up skb_copy_and_csum_bits(): don't bother with the last argument
2020-09-22Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller1-1/+2
Two minor conflicts: 1) net/ipv4/route.c, adding a new local variable while moving another local variable and removing it's initial assignment. 2) drivers/net/dsa/microchip/ksz9477.c, overlapping changes. One pretty prints the port mode differently, whilst another changes the driver to try and obtain the port mode from the port node rather than the switch node. Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-10ip: pass tos into ip_build_and_send_pkt()Wei Wang1-2/+3
This commit adds tos as a new passed in parameter to ip_build_and_send_pkt() which will be used in the later commit. This is a pure restructure and does not have any functional change. Signed-off-by: Wei Wang <weiwan@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-08ip: fix tos reflection in ack and reset packetsWei Wang1-1/+2
Currently, in tcp_v4_reqsk_send_ack() and tcp_v4_send_reset(), we echo the TOS value of the received packets in the response. However, we do not want to echo the lower 2 ECN bits in accordance with RFC 3168 6.1.5 robustness principles. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Wei Wang <weiwan@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-31net: clean up codestyleMiaohe Lin1-1/+1
This is a pure codestyle cleanup patch. No functional change intended. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-31net: Use helper macro IP_MAX_MTU in __ip_append_data()Miaohe Lin1-1/+1
What 0xFFFF means here is actually the max mtu of a ip packet. Use help macro IP_MAX_MTU here. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-25net: clean up codestyle for net/ipv4Miaohe Lin1-1/+1
This is a pure codestyle cleanup patch. Also add a blank line after declarations as warned by checkpatch.pl. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-20csum_partial_copy_nocheck(): drop the last argumentAl Viro1-1/+1
It's always 0. Note that we theoretically could use ~0U as well - result will be the same modulo 0xffff, _if_ the damn thing did the right thing for any value of initial sum; later we'll make use of that when convenient. However, unlike csum_and_copy_..._user(), there are instances that did not work for arbitrary initial sums; c6x is one such. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-08-20skb_copy_and_csum_bits(): don't bother with the last argumentAl Viro1-2/+2
it's always 0 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-11Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller1-1/+1
All conflicts seemed rather trivial, with some guidance from Saeed Mameed on the tc_ct.c one. Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-01ip: Fix SO_MARK in RST, ACK and ICMP packetsWillem de Bruijn1-1/+1
When no full socket is available, skbs are sent over a per-netns control socket. Its sk_mark is temporarily adjusted to match that of the real (request or timewait) socket or to reflect an incoming skb, so that the outgoing skb inherits this in __ip_make_skb. Introduction of the socket cookie mark field broke this. Now the skb is set through the cookie and cork: <caller> # init sockc.mark from sk_mark or cmsg ip_append_data ip_setup_cork # convert sockc.mark to cork mark ip_push_pending_frames ip_finish_skb __ip_make_skb # set skb->mark to cork mark But I missed these special control sockets. Update all callers of __ip(6)_make_skb that were originally missed. For IPv6, the same two icmp(v6) paths are affected. The third case is not, as commit 92e55f412cff ("tcp: don't annotate mark on control socket from tcp_v6_send_response()") replaced the ctl_sk->sk_mark with passing the mark field directly as a function argument. That commit predates the commit that introduced the bug. Fixes: c6af0c227a22 ("ip: support SO_MARK cmsg") Signed-off-by: Willem de Bruijn <willemb@google.com> Reported-by: Martin KaFai Lau <kafai@fb.com> Reviewed-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-06-20tcp: remove indirect calls for icsk->icsk_af_ops->queue_xmitEric Dumazet1-0/+6
Mitigate RETPOLINE costs in __tcp_transmit_skb() by using INDIRECT_CALL_INET() wrapper. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-29net: Fix typo of SKB_SGO_CB_OFFSETCambda Zhu1-1/+1
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 <cambda@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-12inet: Use fallthrough;Joe Perches1-1/+1
Convert the various uses of fallthrough comments to fallthrough; Done via script Link: https://lore.kernel.org/lkml/b56602fcf79f849e733e7b521bb0e17895d390fa.1582230379.git.joe@perches.com/ And by hand: net/ipv6/ip6_fib.c has a fallthrough comment outside of an #ifdef block that causes gcc to emit a warning if converted in-place. So move the new fallthrough; inside the containing #ifdef/#endif too. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-14net: ipv4: use skb_list_walk_safe helper for gso segmentsJason A. Donenfeld1-5/+3
This is a straight-forward conversion case for the new function, keeping the flow of the existing code as intact as possible. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-07inet: protect against too small mtu values.Eric Dumazet1-5/+8
syzbot was once again able to crash a host by setting a very small mtu on loopback device. Let's make inetdev_valid_mtu() available in include/net/ip.h, and use it in ip_setup_cork(), so that we protect both ip_append_page() and __ip_append_data() Also add a READ_ONCE() when the device mtu is read. Pairs this lockless read with one WRITE_ONCE() in __dev_set_mtu(), even if other code paths might write over this field. Add a big comment in include/linux/netdevice.h about dev->mtu needing READ_ONCE()/WRITE_ONCE() annotations. Hopefully we will add the missing ones in followup patches. [1] refcount_t: saturated; leaking memory. WARNING: CPU: 0 PID: 9464 at lib/refcount.c:22 refcount_warn_saturate+0x138/0x1f0 lib/refcount.c:22 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 9464 Comm: syz-executor850 Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 panic+0x2e3/0x75c kernel/panic.c:221 __warn.cold+0x2f/0x3e kernel/panic.c:582 report_bug+0x289/0x300 lib/bug.c:195 fixup_bug arch/x86/kernel/traps.c:174 [inline] fixup_bug arch/x86/kernel/traps.c:169 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027 RIP: 0010:refcount_warn_saturate+0x138/0x1f0 lib/refcount.c:22 Code: 06 31 ff 89 de e8 c8 f5 e6 fd 84 db 0f 85 6f ff ff ff e8 7b f4 e6 fd 48 c7 c7 e0 71 4f 88 c6 05 56 a6 a4 06 01 e8 c7 a8 b7 fd <0f> 0b e9 50 ff ff ff e8 5c f4 e6 fd 0f b6 1d 3d a6 a4 06 31 ff 89 RSP: 0018:ffff88809689f550 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff815e4336 RDI: ffffed1012d13e9c RBP: ffff88809689f560 R08: ffff88809c50a3c0 R09: fffffbfff15d31b1 R10: fffffbfff15d31b0 R11: ffffffff8ae98d87 R12: 0000000000000001 R13: 0000000000040100 R14: ffff888099041104 R15: ffff888218d96e40 refcount_add include/linux/refcount.h:193 [inline] skb_set_owner_w+0x2b6/0x410 net/core/sock.c:1999 sock_wmalloc+0xf1/0x120 net/core/sock.c:2096 ip_append_page+0x7ef/0x1190 net/ipv4/ip_output.c:1383 udp_sendpage+0x1c7/0x480 net/ipv4/udp.c:1276 inet_sendpage+0xdb/0x150 net/ipv4/af_inet.c:821 kernel_sendpage+0x92/0xf0 net/socket.c:3794 sock_sendpage+0x8b/0xc0 net/socket.c:936 pipe_to_sendpage+0x2da/0x3c0 fs/splice.c:458 splice_from_pipe_feed fs/splice.c:512 [inline] __splice_from_pipe+0x3ee/0x7c0 fs/splice.c:636 splice_from_pipe+0x108/0x170 fs/splice.c:671 generic_splice_sendpage+0x3c/0x50 fs/splice.c:842 do_splice_from fs/splice.c:861 [inline] direct_splice_actor+0x123/0x190 fs/splice.c:1035 splice_direct_to_actor+0x3b4/0xa30 fs/splice.c:990 do_splice_direct+0x1da/0x2a0 fs/splice.c:1078 do_sendfile+0x597/0xd00 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1525 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1511 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x441409 Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 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 0f 83 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fffb64c4f78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441409 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000005 RBP: 0000000000073b8a R08: 0000000000000010 R09: 0000000000000010 R10: 0000000000010001 R11: 0000000000000246 R12: 0000000000402180 R13: 0000000000402210 R14: 0000000000000000 R15: 0000000000000000 Kernel Offset: disabled Rebooting in 86400 seconds.. Fixes: 1470ddf7f8ce ("inet: Remove explicit write references to sk/inet in ip_append_data") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-11-15netfilter: Support iif matches in POSTROUTINGPhil Sutter1-2/+2
Instead of generally passing NULL to NF_HOOK_COND() for input device, pass skb->dev which contains input device for routed skbs. Note that iptables (both legacy and nft) reject rules with input interface match from being added to POSTROUTING chains, but nftables allows this. Cc: Eric Garver <eric@garver.life> Signed-off-by: Phil Sutter <phil@nwl.cc> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2019-10-21ipv4: fix IPSKB_FRAG_PMTU handling with fragmentationEric Dumazet1-5/+6
This patch removes the iph field from the state structure, which is not properly initialized. Instead, add a new field to make the "do we want to set DF" be the state bit and move the code to set the DF flag from ip_frag_next(). Joint work with Pablo and Linus. Fixes: 19c3401a917b ("net: ipv4: place control buffer handling away from fragmentation iterators") Reported-by: Patrick Schönthaler <patrick@notvads.ovh> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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