kernel/include/net/tcp.h, branch linux-5.2.y

tcp: fix tcp_set_congestion_control() use from bpf hook

2019-07-28T06:27:16Z

[ Upstream commit 8d650cdedaabb33e85e9b7c517c0c71fcecc1de9 ] Neal reported incorrect use of ns_capable() from bpf hook. bpf_setsockopt(...TCP_CONGESTION...) -> tcp_set_congestion_control() -> ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) -> ns_capable_common() -> current_cred() -> rcu_dereference_protected(current->cred, 1) Accessing 'current' in bpf context makes no sense, since packets are processed from softirq context. As Neal stated : The capability check in tcp_set_congestion_control() was written assuming a system call context, and then was reused from a BPF call site. The fix is to add a new parameter to tcp_set_congestion_control(), so that the ns_capable() call is only performed under the right context. Fixes: 91b5b21c7c16 ("bpf: Add support for changing congestion control") Signed-off-by: Eric Dumazet Cc: Lawrence Brakmo Reported-by: Neal Cardwell Acked-by: Neal Cardwell Acked-by: Lawrence Brakmo Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: be more careful in tcp_fragment()

2019-07-28T06:27:16Z

[ Upstream commit b617158dc096709d8600c53b6052144d12b89fab ] Some applications set tiny SO_SNDBUF values and expect TCP to just work. Recent patches to address CVE-2019-11478 broke them in case of losses, since retransmits might be prevented. We should allow these flows to make progress. This patch allows the first and last skb in retransmit queue to be split even if memory limits are hit. It also adds the some room due to the fact that tcp_sendmsg() and tcp_sendpage() might overshoot sk_wmem_queued by about one full TSO skb (64KB size). Note this allowance was already present in stable backports for kernels < 4.15 Note for < 4.15 backports : tcp_rtx_queue_tail() will probably look like : static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk) { struct sk_buff *skb = tcp_send_head(sk); return skb ? tcp_write_queue_prev(sk, skb) : tcp_write_queue_tail(sk); } Fixes: f070ef2ac667 ("tcp: tcp_fragment() should apply sane memory limits") Signed-off-by: Eric Dumazet Reported-by: Andrew Prout Tested-by: Andrew Prout Tested-by: Jonathan Lemon Tested-by: Michal Kubecek Acked-by: Neal Cardwell Acked-by: Yuchung Cheng Acked-by: Christoph Paasch Cc: Jonathan Looney Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: limit payload size of sacked skbs

2019-06-16T01:47:31Z

Jonathan Looney reported that TCP can trigger the following crash in tcp_shifted_skb() : BUG_ON(tcp_skb_pcount(skb) < pcount); This can happen if the remote peer has advertized the smallest MSS that linux TCP accepts : 48 An skb can hold 17 fragments, and each fragment can hold 32KB on x86, or 64KB on PowerPC. This means that the 16bit witdh of TCP_SKB_CB(skb)->tcp_gso_segs can overflow. Note that tcp_sendmsg() builds skbs with less than 64KB of payload, so this problem needs SACK to be enabled. SACK blocks allow TCP to coalesce multiple skbs in the retransmit queue, thus filling the 17 fragments to maximal capacity. CVE-2019-11477 -- u16 overflow of TCP_SKB_CB(skb)->tcp_gso_segs Fixes: 832d11c5cd07 ("tcp: Try to restore large SKBs while SACK processing") Signed-off-by: Eric Dumazet Reported-by: Jonathan Looney Acked-by: Neal Cardwell Reviewed-by: Tyler Hicks Cc: Yuchung Cheng Cc: Bruce Curtis Cc: Jonathan Lemon Signed-off-by: David S. Miller

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman

net/tcp: use deferred jump label for TCP acked data hook

2019-05-09T18:13:57Z

User space can flip the clean_acked_data_enabled static branch on and off with TLS offload when CONFIG_TLS_DEVICE is enabled. jump_label.h suggests we use the delayed version in this case. Deferred branches now also don't take the branch mutex on decrement, so we avoid potential locking issues. Signed-off-by: Jakub Kicinski Reviewed-by: Simon Horman Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller

include/net/tcp.h: whitespace cleanup at tcp_v4_check

2019-04-23T04:45:58Z

This patch makes trivial whitespace fix to the function tcp_v4_check at include/net/tcp.h file. It has stylistic issue, which is "space required after that ','" and it can be confirmed with ./scripts/checkpatch.pl tool. ERROR: space required after that ',' (ctx:VxV) #29: FILE: include/net/tcp.h:1317: + return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base); ^ Signed-off-by: Daniel T. Lee Signed-off-by: David S. Miller

tcp: convert tcp_md5_needed to static_branch API

2019-02-26T21:16:03Z

We prefer static_branch_unlikely() over static_key_false() these days. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

tcp: get rid of __tcp_add_write_queue_tail()

2019-02-26T21:16:03Z

This helper is only used from tcp_add_write_queue_tail(), and does not make the code more readable. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

tcp: get rid of tcp_check_send_head()

2019-02-26T21:16:02Z

This helper is used only once, and its name is no longer relevant. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

tcp: allow zerocopy with fastopen

2019-01-26T06:41:08Z

Accept MSG_ZEROCOPY in all the TCP states that allow sendmsg. Remove the explicit check for ESTABLISHED and CLOSE_WAIT states. This requires correctly handling zerocopy state (uarg, sk_zckey) in all paths reachable from other TCP states. Such as the EPIPE case in sk_stream_wait_connect, which a sendmsg() in incorrect state will now hit. Most paths are already safe. Only extension needed is for TCP Fastopen active open. This can build an skb with data in tcp_send_syn_data. Pass the uarg along with other fastopen state, so that this skb also generates a zerocopy notification on release. Tested with active and passive tcp fastopen packetdrill scripts at https://github.com/wdebruij/packetdrill/commit/1747eef03d25a2404e8132817d0f1244fd6f129d Signed-off-by: Willem de Bruijn Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller