BMC/Intel-BMC/linux.git/net/ipv4/tcp.c, branch dev-5.2

tcp: remove empty skb from write queue in error cases

2019-09-10T09:35:06+00:00

[ Upstream commit fdfc5c8594c24c5df883583ebd286321a80e0a67 ] Vladimir Rutsky reported stuck TCP sessions after memory pressure events. Edge Trigger epoll() user would never receive an EPOLLOUT notification allowing them to retry a sendmsg(). Jason tested the case of sk_stream_alloc_skb() returning NULL, but there are other paths that could lead both sendmsg() and sendpage() to return -1 (EAGAIN), with an empty skb queued on the write queue. This patch makes sure we remove this empty skb so that Jason code can detect that the queue is empty, and call sk->sk_write_space(sk) accordingly. Fixes: ce5ec440994b ("tcp: ensure epoll edge trigger wakeup when write queue is empty") Signed-off-by: Eric Dumazet Cc: Jason Baron Reported-by: Vladimir Rutsky Cc: Soheil Hassas Yeganeh Cc: Neal Cardwell Acked-by: Soheil Hassas Yeganeh Acked-by: Neal Cardwell Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net/tls: prevent skb_orphan() from leaking TLS plain text with offload

2019-08-25T14:10:38+00:00

[ Upstream commit 414776621d1006e57e80e6db7fdc3837897aaa64 ] sk_validate_xmit_skb() and drivers depend on the sk member of struct sk_buff to identify segments requiring encryption. Any operation which removes or does not preserve the original TLS socket such as skb_orphan() or skb_clone() will cause clear text leaks. Make the TCP socket underlying an offloaded TLS connection mark all skbs as decrypted, if TLS TX is in offload mode. Then in sk_validate_xmit_skb() catch skbs which have no socket (or a socket with no validation) and decrypted flag set. Note that CONFIG_SOCK_VALIDATE_XMIT, CONFIG_TLS_DEVICE and sk->sk_validate_xmit_skb are slightly interchangeable right now, they all imply TLS offload. The new checks are guarded by CONFIG_TLS_DEVICE because that's the option guarding the sk_buff->decrypted member. Second, smaller issue with orphaning is that it breaks the guarantee that packets will be delivered to device queues in-order. All TLS offload drivers depend on that scheduling property. This means skb_orphan_partial()'s trick of preserving partial socket references will cause issues in the drivers. We need a full orphan, and as a result netem delay/throttling will cause all TLS offload skbs to be dropped. Reusing the sk_buff->decrypted flag also protects from leaking clear text when incoming, decrypted skb is redirected (e.g. by TC). See commit 0608c69c9a80 ("bpf: sk_msg, sock{map|hash} redirect through ULP") for justification why the internal flag is safe. The only location which could leak the flag in is tcp_bpf_sendmsg(), which is taken care of by clearing the previously unused bit. v2: - remove superfluous decrypted mark copy (Willem); - remove the stale doc entry (Boris); - rely entirely on EOR marking to prevent coalescing (Boris); - use an internal sendpages flag instead of marking the socket (Boris). v3 (Willem): - reorganize the can_skb_orphan_partial() condition; - fix the flag leak-in through tcp_bpf_sendmsg. Signed-off-by: Jakub Kicinski Acked-by: Willem de Bruijn Reviewed-by: Boris Pismenny Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: Reset bytes_acked and bytes_received when disconnecting

2019-07-28T06:27:17+00:00

[ Upstream commit e858faf556d4e14c750ba1e8852783c6f9520a0e ] If an app is playing tricks to reuse a socket via tcp_disconnect(), bytes_acked/received needs to be reset to 0. Otherwise tcp_info will report the sum of the current and the old connection.. Cc: Eric Dumazet Fixes: 0df48c26d841 ("tcp: add tcpi_bytes_acked to tcp_info") Fixes: bdd1f9edacb5 ("tcp: add tcpi_bytes_received to tcp_info") Signed-off-by: Christoph Paasch Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: fix tcp_set_congestion_control() use from bpf hook

2019-07-28T06:27:16+00:00

[ 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

Merge branch 'tcp-fixes'

2019-06-17T17:39:56+00:00

Eric Dumazet says: ==================== tcp: make sack processing more robust Jonathan Looney brought to our attention multiple problems in TCP stack at the sender side. SACK processing can be abused by malicious peers to either cause overflows, or increase of memory usage. First two patches fix the immediate problems. Since the malicious peers abuse senders by advertizing a very small MSS in their SYN or SYNACK packet, the last two patches add a new sysctl so that admins can chose a higher limit for MSS clamping. ==================== Signed-off-by: David S. Miller

tcp: fix compile error if !CONFIG_SYSCTL

2019-06-16T21:15:07+00:00

tcp_tx_skb_cache_key and tcp_rx_skb_cache_key must be available even if CONFIG_SYSCTL is not set. Fixes: 0b7d7f6b2208 ("tcp: add tcp_tx_skb_cache sysctl") Fixes: ede61ca474a0 ("tcp: add tcp_rx_skb_cache sysctl") Signed-off-by: Eric Dumazet Reported-by: Willem de Bruijn Signed-off-by: David S. Miller

tcp: limit payload size of sacked skbs

2019-06-16T01:47:31+00:00

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

2019-05-30T18:26:32+00:00

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

tcp: do not recycle cloned skbs

2019-05-15T16:22:41+00:00

It is illegal to change arbitrary fields in skb_shared_info if the skb is cloned. Before calling skb_zcopy_clear() we need to ensure this rule, therefore we need to move the test from sk_stream_alloc_skb() to sk_wmem_free_skb() Fixes: 4f661542a402 ("tcp: fix zerocopy and notsent_lowat issues") Signed-off-by: Eric Dumazet Diagnosed-by: Willem de Bruijn Signed-off-by: David S. Miller

tcp: refactor setting the initial congestion window

2019-05-01T15:47:54+00:00

Relocate the congestion window initialization from tcp_init_metrics() to tcp_init_transfer() to improve code readability. Signed-off-by: Yuchung Cheng Signed-off-by: Neal Cardwell Signed-off-by: Soheil Hassas Yeganeh Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller