BMC/Intel-BMC/linux.git/net/ipv4, branch v5.1.14

tcp: refine memory limit test in tcp_fragment()

2019-06-22T09:09:17+00:00

commit b6653b3629e5b88202be3c9abc44713973f5c4b4 upstream. tcp_fragment() might be called for skbs in the write queue. Memory limits might have been exceeded because tcp_sendmsg() only checks limits at full skb (64KB) boundaries. Therefore, we need to make sure tcp_fragment() wont punish applications that might have setup very low SO_SNDBUF values. Fixes: f070ef2ac667 ("tcp: tcp_fragment() should apply sane memory limits") Signed-off-by: Eric Dumazet Reported-by: Christoph Paasch Tested-by: Christoph Paasch Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

netfilter: nft_fib: Fix existence check support

2019-06-22T06:09:08+00:00

[ Upstream commit e633508a95289489d28faacb68b32c3e7e68ef6f ] NFTA_FIB_F_PRESENT flag was not always honored since eval functions did not call nft_fib_store_result in all cases. Given that in all callsites there is a struct net_device pointer available which holds the interface data to be stored in destination register, simplify nft_fib_store_result() to just accept that pointer instead of the nft_pktinfo pointer and interface index. This also allows to drop the index to interface lookup previously needed to get the name associated with given index. Fixes: 055c4b34b94f6 ("netfilter: nft_fib: Support existence check") Signed-off-by: Phil Sutter Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

net: correct udp zerocopy refcnt also when zerocopy only on append

2019-06-22T06:09:07+00:00

[ Upstream commit 522924b583082f51b8a2406624a2f27c22119b20 ] The below patch fixes an incorrect zerocopy refcnt increment when appending with MSG_MORE to an existing zerocopy udp skb. send(.., MSG_ZEROCOPY | MSG_MORE); // refcnt 1 send(.., MSG_ZEROCOPY | MSG_MORE); // refcnt still 1 (bar frags) But it missed that zerocopy need not be passed at the first send. The right test whether the uarg is newly allocated and thus has extra refcnt 1 is not !skb, but !skb_zcopy. send(.., MSG_MORE); // send(.., MSG_ZEROCOPY); // refcnt 1 Fixes: 100f6d8e09905 ("net: correct zerocopy refcnt with udp MSG_MORE") Reported-by: syzbot Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

bpf, tcp: correctly handle DONT_WAIT flags and timeo == 0

2019-06-19T06:00:08+00:00

[ Upstream commit 5fa2ca7c4a3fc176f31b495e1a704862d8188b53 ] The tcp_bpf_wait_data() routine needs to check timeo != 0 before calling sk_wait_event() otherwise we may see unexpected stalls on receiver. Arika did all the leg work here I just formatted, posted and ran a few tests. Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface") Reported-by: Arika Chen Suggested-by: Arika Chen Signed-off-by: John Fastabend Signed-off-by: Daniel Borkmann Signed-off-by: Sasha Levin

bpf: sockmap remove duplicate queue free

2019-06-19T06:00:06+00:00

[ Upstream commit c42253cc88206fd0e9868c8b2fd7f9e79f9e0e03 ] In tcp bpf remove we free the cork list and purge the ingress msg list. However we do this before the ref count reaches zero so it could be possible some other access is in progress. In this case (tcp close and/or tcp_unhash) we happen to also hold the sock lock so no path exists but lets fix it otherwise it is extremely fragile and breaks the reference counting rules. Also we already check the cork list and ingress msg queue and free them once the ref count reaches zero so its wasteful to check twice. Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: John Fastabend Signed-off-by: Daniel Borkmann Signed-off-by: Sasha Levin

tcp: enforce tcp_min_snd_mss in tcp_mtu_probing()

2019-06-17T17:50:37+00:00

commit 967c05aee439e6e5d7d805e195b3a20ef5c433d6 upstream. If mtu probing is enabled tcp_mtu_probing() could very well end up with a too small MSS. Use the new sysctl tcp_min_snd_mss to make sure MSS search is performed in an acceptable range. CVE-2019-11479 -- tcp mss hardcoded to 48 Signed-off-by: Eric Dumazet Reported-by: Jonathan Lemon Cc: Jonathan Looney Acked-by: Neal Cardwell Cc: Yuchung Cheng Cc: Tyler Hicks Cc: Bruce Curtis Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: add tcp_min_snd_mss sysctl

2019-06-17T17:50:37+00:00

commit 5f3e2bf008c2221478101ee72f5cb4654b9fc363 upstream. Some TCP peers announce a very small MSS option in their SYN and/or SYN/ACK messages. This forces the stack to send packets with a very high network/cpu overhead. Linux has enforced a minimal value of 48. Since this value includes the size of TCP options, and that the options can consume up to 40 bytes, this means that each segment can include only 8 bytes of payload. In some cases, it can be useful to increase the minimal value to a saner value. We still let the default to 48 (TCP_MIN_SND_MSS), for compatibility reasons. Note that TCP_MAXSEG socket option enforces a minimal value of (TCP_MIN_MSS). David Miller increased this minimal value in commit c39508d6f118 ("tcp: Make TCP_MAXSEG minimum more correct.") from 64 to 88. We might in the future merge TCP_MIN_SND_MSS and TCP_MIN_MSS. CVE-2019-11479 -- tcp mss hardcoded to 48 Signed-off-by: Eric Dumazet Suggested-by: Jonathan Looney Acked-by: Neal Cardwell Cc: Yuchung Cheng Cc: Tyler Hicks Cc: Bruce Curtis Cc: Jonathan Lemon Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: tcp_fragment() should apply sane memory limits

2019-06-17T17:50:36+00:00

commit f070ef2ac66716357066b683fb0baf55f8191a2e upstream. Jonathan Looney reported that a malicious peer can force a sender to fragment its retransmit queue into tiny skbs, inflating memory usage and/or overflow 32bit counters. TCP allows an application to queue up to sk_sndbuf bytes, so we need to give some allowance for non malicious splitting of retransmit queue. A new SNMP counter is added to monitor how many times TCP did not allow to split an skb if the allowance was exceeded. Note that this counter might increase in the case applications use SO_SNDBUF socket option to lower sk_sndbuf. CVE-2019-11478 : tcp_fragment, prevent fragmenting a packet when the socket is already using more than half the allowed space Signed-off-by: Eric Dumazet Reported-by: Jonathan Looney Acked-by: Neal Cardwell Acked-by: Yuchung Cheng Reviewed-by: Tyler Hicks Cc: Bruce Curtis Cc: Jonathan Lemon Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: limit payload size of sacked skbs

2019-06-17T17:50:36+00:00

commit 3b4929f65b0d8249f19a50245cd88ed1a2f78cff upstream. 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 Signed-off-by: Greg Kroah-Hartman

ipmr_base: Do not reset index in mr_table_dump

2019-06-11T10:19:13+00:00

[ Upstream commit 7fcd1e033dacedd520abebc943c960dcf5add3ae ] e is the counter used to save the location of a dump when an skb is filled. Once the walk of the table is complete, mr_table_dump needs to return without resetting that index to 0. Dump of a specific table is looping because of the reset because there is no way to indicate the walk of the table is done. Move the reset to the caller so the dump of each table starts at 0, but the loop counter is maintained if a dump fills an skb. Fixes: e1cedae1ba6b0 ("ipmr: Refactor mr_rtm_dumproute") Signed-off-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman