![Eric W. Biederman](/assets/img/avatar_default.png)
In preparation for supporting the creation of network namespaces by unprivileged users, modify all of the per net sysctl exports and refuse to allow them to unprivileged users. This makes it safe for unprivileged users in general to access per net sysctls, and allows sysctls to be exported to unprivileged users on an individual basis as they are deemed safe. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
989 lines
28 KiB
C
989 lines
28 KiB
C
/*
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* DCCP connection tracking protocol helper
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*
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* Copyright (c) 2005, 2006, 2008 Patrick McHardy <kaber@trash.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/sysctl.h>
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#include <linux/spinlock.h>
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#include <linux/skbuff.h>
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#include <linux/dccp.h>
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#include <linux/slab.h>
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#include <net/net_namespace.h>
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#include <net/netns/generic.h>
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#include <linux/netfilter/nfnetlink_conntrack.h>
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#include <net/netfilter/nf_conntrack.h>
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#include <net/netfilter/nf_conntrack_l4proto.h>
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#include <net/netfilter/nf_conntrack_ecache.h>
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#include <net/netfilter/nf_log.h>
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/* Timeouts are based on values from RFC4340:
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*
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* - REQUEST:
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*
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* 8.1.2. Client Request
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*
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* A client MAY give up on its DCCP-Requests after some time
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* (3 minutes, for example).
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*
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* - RESPOND:
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*
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* 8.1.3. Server Response
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*
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* It MAY also leave the RESPOND state for CLOSED after a timeout of
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* not less than 4MSL (8 minutes);
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*
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* - PARTOPEN:
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*
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* 8.1.5. Handshake Completion
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*
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* If the client remains in PARTOPEN for more than 4MSL (8 minutes),
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* it SHOULD reset the connection with Reset Code 2, "Aborted".
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*
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* - OPEN:
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*
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* The DCCP timestamp overflows after 11.9 hours. If the connection
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* stays idle this long the sequence number won't be recognized
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* as valid anymore.
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*
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* - CLOSEREQ/CLOSING:
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*
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* 8.3. Termination
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*
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* The retransmission timer should initially be set to go off in two
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* round-trip times and should back off to not less than once every
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* 64 seconds ...
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*
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* - TIMEWAIT:
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*
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* 4.3. States
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*
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* A server or client socket remains in this state for 2MSL (4 minutes)
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* after the connection has been town down, ...
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*/
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#define DCCP_MSL (2 * 60 * HZ)
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static const char * const dccp_state_names[] = {
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[CT_DCCP_NONE] = "NONE",
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[CT_DCCP_REQUEST] = "REQUEST",
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[CT_DCCP_RESPOND] = "RESPOND",
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[CT_DCCP_PARTOPEN] = "PARTOPEN",
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[CT_DCCP_OPEN] = "OPEN",
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[CT_DCCP_CLOSEREQ] = "CLOSEREQ",
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[CT_DCCP_CLOSING] = "CLOSING",
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[CT_DCCP_TIMEWAIT] = "TIMEWAIT",
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[CT_DCCP_IGNORE] = "IGNORE",
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[CT_DCCP_INVALID] = "INVALID",
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};
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#define sNO CT_DCCP_NONE
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#define sRQ CT_DCCP_REQUEST
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#define sRS CT_DCCP_RESPOND
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#define sPO CT_DCCP_PARTOPEN
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#define sOP CT_DCCP_OPEN
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#define sCR CT_DCCP_CLOSEREQ
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#define sCG CT_DCCP_CLOSING
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#define sTW CT_DCCP_TIMEWAIT
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#define sIG CT_DCCP_IGNORE
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#define sIV CT_DCCP_INVALID
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/*
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* DCCP state transition table
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*
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* The assumption is the same as for TCP tracking:
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*
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* We are the man in the middle. All the packets go through us but might
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* get lost in transit to the destination. It is assumed that the destination
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* can't receive segments we haven't seen.
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*
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* The following states exist:
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*
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* NONE: Initial state, expecting Request
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* REQUEST: Request seen, waiting for Response from server
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* RESPOND: Response from server seen, waiting for Ack from client
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* PARTOPEN: Ack after Response seen, waiting for packet other than Response,
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* Reset or Sync from server
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* OPEN: Packet other than Response, Reset or Sync seen
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* CLOSEREQ: CloseReq from server seen, expecting Close from client
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* CLOSING: Close seen, expecting Reset
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* TIMEWAIT: Reset seen
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* IGNORE: Not determinable whether packet is valid
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*
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* Some states exist only on one side of the connection: REQUEST, RESPOND,
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* PARTOPEN, CLOSEREQ. For the other side these states are equivalent to
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* the one it was in before.
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*
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* Packets are marked as ignored (sIG) if we don't know if they're valid
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* (for example a reincarnation of a connection we didn't notice is dead
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* already) and the server may send back a connection closing Reset or a
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* Response. They're also used for Sync/SyncAck packets, which we don't
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* care about.
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*/
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static const u_int8_t
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dccp_state_table[CT_DCCP_ROLE_MAX + 1][DCCP_PKT_SYNCACK + 1][CT_DCCP_MAX + 1] = {
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[CT_DCCP_ROLE_CLIENT] = {
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[DCCP_PKT_REQUEST] = {
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/*
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* sNO -> sRQ Regular Request
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* sRQ -> sRQ Retransmitted Request or reincarnation
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* sRS -> sRS Retransmitted Request (apparently Response
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* got lost after we saw it) or reincarnation
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* sPO -> sIG Ignore, conntrack might be out of sync
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* sOP -> sIG Ignore, conntrack might be out of sync
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* sCR -> sIG Ignore, conntrack might be out of sync
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* sCG -> sIG Ignore, conntrack might be out of sync
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* sTW -> sRQ Reincarnation
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*
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* sNO, sRQ, sRS, sPO. sOP, sCR, sCG, sTW, */
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sRQ, sRQ, sRS, sIG, sIG, sIG, sIG, sRQ,
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},
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[DCCP_PKT_RESPONSE] = {
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/*
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* sNO -> sIV Invalid
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* sRQ -> sIG Ignore, might be response to ignored Request
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* sRS -> sIG Ignore, might be response to ignored Request
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* sPO -> sIG Ignore, might be response to ignored Request
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* sOP -> sIG Ignore, might be response to ignored Request
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* sCR -> sIG Ignore, might be response to ignored Request
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* sCG -> sIG Ignore, might be response to ignored Request
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* sTW -> sIV Invalid, reincarnation in reverse direction
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* goes through sRQ
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIV,
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},
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[DCCP_PKT_ACK] = {
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/*
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* sNO -> sIV No connection
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* sRQ -> sIV No connection
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* sRS -> sPO Ack for Response, move to PARTOPEN (8.1.5.)
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* sPO -> sPO Retransmitted Ack for Response, remain in PARTOPEN
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* sOP -> sOP Regular ACK, remain in OPEN
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* sCR -> sCR Ack in CLOSEREQ MAY be processed (8.3.)
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* sCG -> sCG Ack in CLOSING MAY be processed (8.3.)
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* sTW -> sIV
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV
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},
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[DCCP_PKT_DATA] = {
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/*
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* sNO -> sIV No connection
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* sRQ -> sIV No connection
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* sRS -> sIV No connection
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* sPO -> sIV MUST use DataAck in PARTOPEN state (8.1.5.)
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* sOP -> sOP Regular Data packet
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* sCR -> sCR Data in CLOSEREQ MAY be processed (8.3.)
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* sCG -> sCG Data in CLOSING MAY be processed (8.3.)
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* sTW -> sIV
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIV, sIV, sIV, sIV, sOP, sCR, sCG, sIV,
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},
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[DCCP_PKT_DATAACK] = {
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/*
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* sNO -> sIV No connection
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* sRQ -> sIV No connection
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* sRS -> sPO Ack for Response, move to PARTOPEN (8.1.5.)
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* sPO -> sPO Remain in PARTOPEN state
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* sOP -> sOP Regular DataAck packet in OPEN state
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* sCR -> sCR DataAck in CLOSEREQ MAY be processed (8.3.)
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* sCG -> sCG DataAck in CLOSING MAY be processed (8.3.)
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* sTW -> sIV
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV
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},
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[DCCP_PKT_CLOSEREQ] = {
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/*
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* CLOSEREQ may only be sent by the server.
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV
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},
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[DCCP_PKT_CLOSE] = {
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/*
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* sNO -> sIV No connection
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* sRQ -> sIV No connection
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* sRS -> sIV No connection
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* sPO -> sCG Client-initiated close
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* sOP -> sCG Client-initiated close
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* sCR -> sCG Close in response to CloseReq (8.3.)
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* sCG -> sCG Retransmit
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* sTW -> sIV Late retransmit, already in TIME_WAIT
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIV, sIV, sIV, sCG, sCG, sCG, sIV, sIV
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},
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[DCCP_PKT_RESET] = {
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/*
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* sNO -> sIV No connection
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* sRQ -> sTW Sync received or timeout, SHOULD send Reset (8.1.1.)
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* sRS -> sTW Response received without Request
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* sPO -> sTW Timeout, SHOULD send Reset (8.1.5.)
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* sOP -> sTW Connection reset
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* sCR -> sTW Connection reset
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* sCG -> sTW Connection reset
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* sTW -> sIG Ignore (don't refresh timer)
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIV, sTW, sTW, sTW, sTW, sTW, sTW, sIG
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},
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[DCCP_PKT_SYNC] = {
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/*
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* We currently ignore Sync packets
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
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},
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[DCCP_PKT_SYNCACK] = {
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/*
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* We currently ignore SyncAck packets
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
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},
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},
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[CT_DCCP_ROLE_SERVER] = {
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[DCCP_PKT_REQUEST] = {
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/*
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* sNO -> sIV Invalid
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* sRQ -> sIG Ignore, conntrack might be out of sync
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* sRS -> sIG Ignore, conntrack might be out of sync
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* sPO -> sIG Ignore, conntrack might be out of sync
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* sOP -> sIG Ignore, conntrack might be out of sync
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* sCR -> sIG Ignore, conntrack might be out of sync
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* sCG -> sIG Ignore, conntrack might be out of sync
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* sTW -> sRQ Reincarnation, must reverse roles
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIV, sIG, sIG, sIG, sIG, sIG, sIG, sRQ
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},
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[DCCP_PKT_RESPONSE] = {
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/*
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* sNO -> sIV Response without Request
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* sRQ -> sRS Response to clients Request
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* sRS -> sRS Retransmitted Response (8.1.3. SHOULD NOT)
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* sPO -> sIG Response to an ignored Request or late retransmit
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* sOP -> sIG Ignore, might be response to ignored Request
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* sCR -> sIG Ignore, might be response to ignored Request
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* sCG -> sIG Ignore, might be response to ignored Request
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* sTW -> sIV Invalid, Request from client in sTW moves to sRQ
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIV, sRS, sRS, sIG, sIG, sIG, sIG, sIV
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},
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[DCCP_PKT_ACK] = {
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/*
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* sNO -> sIV No connection
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* sRQ -> sIV No connection
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* sRS -> sIV No connection
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* sPO -> sOP Enter OPEN state (8.1.5.)
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* sOP -> sOP Regular Ack in OPEN state
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* sCR -> sIV Waiting for Close from client
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* sCG -> sCG Ack in CLOSING MAY be processed (8.3.)
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* sTW -> sIV
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
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},
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[DCCP_PKT_DATA] = {
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/*
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* sNO -> sIV No connection
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* sRQ -> sIV No connection
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* sRS -> sIV No connection
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* sPO -> sOP Enter OPEN state (8.1.5.)
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* sOP -> sOP Regular Data packet in OPEN state
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* sCR -> sIV Waiting for Close from client
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* sCG -> sCG Data in CLOSING MAY be processed (8.3.)
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* sTW -> sIV
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
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},
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[DCCP_PKT_DATAACK] = {
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/*
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* sNO -> sIV No connection
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* sRQ -> sIV No connection
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* sRS -> sIV No connection
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* sPO -> sOP Enter OPEN state (8.1.5.)
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* sOP -> sOP Regular DataAck in OPEN state
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* sCR -> sIV Waiting for Close from client
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* sCG -> sCG Data in CLOSING MAY be processed (8.3.)
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* sTW -> sIV
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
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},
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[DCCP_PKT_CLOSEREQ] = {
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/*
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* sNO -> sIV No connection
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* sRQ -> sIV No connection
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* sRS -> sIV No connection
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* sPO -> sOP -> sCR Move directly to CLOSEREQ (8.1.5.)
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* sOP -> sCR CloseReq in OPEN state
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* sCR -> sCR Retransmit
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* sCG -> sCR Simultaneous close, client sends another Close
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* sTW -> sIV Already closed
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIV, sIV, sIV, sCR, sCR, sCR, sCR, sIV
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},
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[DCCP_PKT_CLOSE] = {
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/*
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* sNO -> sIV No connection
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* sRQ -> sIV No connection
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* sRS -> sIV No connection
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* sPO -> sOP -> sCG Move direcly to CLOSING
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* sOP -> sCG Move to CLOSING
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* sCR -> sIV Close after CloseReq is invalid
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* sCG -> sCG Retransmit
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* sTW -> sIV Already closed
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIV, sIV, sIV, sCG, sCG, sIV, sCG, sIV
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},
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[DCCP_PKT_RESET] = {
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/*
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* sNO -> sIV No connection
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* sRQ -> sTW Reset in response to Request
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* sRS -> sTW Timeout, SHOULD send Reset (8.1.3.)
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* sPO -> sTW Timeout, SHOULD send Reset (8.1.3.)
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* sOP -> sTW
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* sCR -> sTW
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* sCG -> sTW
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* sTW -> sIG Ignore (don't refresh timer)
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW, sTW */
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sIV, sTW, sTW, sTW, sTW, sTW, sTW, sTW, sIG
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},
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[DCCP_PKT_SYNC] = {
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/*
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* We currently ignore Sync packets
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
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},
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[DCCP_PKT_SYNCACK] = {
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/*
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* We currently ignore SyncAck packets
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*
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* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
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sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
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},
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},
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};
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/* this module per-net specifics */
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static int dccp_net_id __read_mostly;
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struct dccp_net {
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struct nf_proto_net pn;
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int dccp_loose;
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unsigned int dccp_timeout[CT_DCCP_MAX + 1];
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};
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static inline struct dccp_net *dccp_pernet(struct net *net)
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{
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return net_generic(net, dccp_net_id);
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}
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static bool dccp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
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struct nf_conntrack_tuple *tuple)
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{
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struct dccp_hdr _hdr, *dh;
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dh = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
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if (dh == NULL)
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return false;
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tuple->src.u.dccp.port = dh->dccph_sport;
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tuple->dst.u.dccp.port = dh->dccph_dport;
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return true;
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}
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static bool dccp_invert_tuple(struct nf_conntrack_tuple *inv,
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const struct nf_conntrack_tuple *tuple)
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{
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inv->src.u.dccp.port = tuple->dst.u.dccp.port;
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inv->dst.u.dccp.port = tuple->src.u.dccp.port;
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return true;
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}
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static bool dccp_new(struct nf_conn *ct, const struct sk_buff *skb,
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unsigned int dataoff, unsigned int *timeouts)
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{
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struct net *net = nf_ct_net(ct);
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struct dccp_net *dn;
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struct dccp_hdr _dh, *dh;
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const char *msg;
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u_int8_t state;
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dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
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BUG_ON(dh == NULL);
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|
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state = dccp_state_table[CT_DCCP_ROLE_CLIENT][dh->dccph_type][CT_DCCP_NONE];
|
|
switch (state) {
|
|
default:
|
|
dn = dccp_pernet(net);
|
|
if (dn->dccp_loose == 0) {
|
|
msg = "nf_ct_dccp: not picking up existing connection ";
|
|
goto out_invalid;
|
|
}
|
|
case CT_DCCP_REQUEST:
|
|
break;
|
|
case CT_DCCP_INVALID:
|
|
msg = "nf_ct_dccp: invalid state transition ";
|
|
goto out_invalid;
|
|
}
|
|
|
|
ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT;
|
|
ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER;
|
|
ct->proto.dccp.state = CT_DCCP_NONE;
|
|
ct->proto.dccp.last_pkt = DCCP_PKT_REQUEST;
|
|
ct->proto.dccp.last_dir = IP_CT_DIR_ORIGINAL;
|
|
ct->proto.dccp.handshake_seq = 0;
|
|
return true;
|
|
|
|
out_invalid:
|
|
if (LOG_INVALID(net, IPPROTO_DCCP))
|
|
nf_log_packet(nf_ct_l3num(ct), 0, skb, NULL, NULL, NULL, msg);
|
|
return false;
|
|
}
|
|
|
|
static u64 dccp_ack_seq(const struct dccp_hdr *dh)
|
|
{
|
|
const struct dccp_hdr_ack_bits *dhack;
|
|
|
|
dhack = (void *)dh + __dccp_basic_hdr_len(dh);
|
|
return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) +
|
|
ntohl(dhack->dccph_ack_nr_low);
|
|
}
|
|
|
|
static unsigned int *dccp_get_timeouts(struct net *net)
|
|
{
|
|
return dccp_pernet(net)->dccp_timeout;
|
|
}
|
|
|
|
static int dccp_packet(struct nf_conn *ct, const struct sk_buff *skb,
|
|
unsigned int dataoff, enum ip_conntrack_info ctinfo,
|
|
u_int8_t pf, unsigned int hooknum,
|
|
unsigned int *timeouts)
|
|
{
|
|
struct net *net = nf_ct_net(ct);
|
|
enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
|
|
struct dccp_hdr _dh, *dh;
|
|
u_int8_t type, old_state, new_state;
|
|
enum ct_dccp_roles role;
|
|
|
|
dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
|
|
BUG_ON(dh == NULL);
|
|
type = dh->dccph_type;
|
|
|
|
if (type == DCCP_PKT_RESET &&
|
|
!test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
|
|
/* Tear down connection immediately if only reply is a RESET */
|
|
nf_ct_kill_acct(ct, ctinfo, skb);
|
|
return NF_ACCEPT;
|
|
}
|
|
|
|
spin_lock_bh(&ct->lock);
|
|
|
|
role = ct->proto.dccp.role[dir];
|
|
old_state = ct->proto.dccp.state;
|
|
new_state = dccp_state_table[role][type][old_state];
|
|
|
|
switch (new_state) {
|
|
case CT_DCCP_REQUEST:
|
|
if (old_state == CT_DCCP_TIMEWAIT &&
|
|
role == CT_DCCP_ROLE_SERVER) {
|
|
/* Reincarnation in the reverse direction: reopen and
|
|
* reverse client/server roles. */
|
|
ct->proto.dccp.role[dir] = CT_DCCP_ROLE_CLIENT;
|
|
ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_SERVER;
|
|
}
|
|
break;
|
|
case CT_DCCP_RESPOND:
|
|
if (old_state == CT_DCCP_REQUEST)
|
|
ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh);
|
|
break;
|
|
case CT_DCCP_PARTOPEN:
|
|
if (old_state == CT_DCCP_RESPOND &&
|
|
type == DCCP_PKT_ACK &&
|
|
dccp_ack_seq(dh) == ct->proto.dccp.handshake_seq)
|
|
set_bit(IPS_ASSURED_BIT, &ct->status);
|
|
break;
|
|
case CT_DCCP_IGNORE:
|
|
/*
|
|
* Connection tracking might be out of sync, so we ignore
|
|
* packets that might establish a new connection and resync
|
|
* if the server responds with a valid Response.
|
|
*/
|
|
if (ct->proto.dccp.last_dir == !dir &&
|
|
ct->proto.dccp.last_pkt == DCCP_PKT_REQUEST &&
|
|
type == DCCP_PKT_RESPONSE) {
|
|
ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_CLIENT;
|
|
ct->proto.dccp.role[dir] = CT_DCCP_ROLE_SERVER;
|
|
ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh);
|
|
new_state = CT_DCCP_RESPOND;
|
|
break;
|
|
}
|
|
ct->proto.dccp.last_dir = dir;
|
|
ct->proto.dccp.last_pkt = type;
|
|
|
|
spin_unlock_bh(&ct->lock);
|
|
if (LOG_INVALID(net, IPPROTO_DCCP))
|
|
nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
|
|
"nf_ct_dccp: invalid packet ignored ");
|
|
return NF_ACCEPT;
|
|
case CT_DCCP_INVALID:
|
|
spin_unlock_bh(&ct->lock);
|
|
if (LOG_INVALID(net, IPPROTO_DCCP))
|
|
nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
|
|
"nf_ct_dccp: invalid state transition ");
|
|
return -NF_ACCEPT;
|
|
}
|
|
|
|
ct->proto.dccp.last_dir = dir;
|
|
ct->proto.dccp.last_pkt = type;
|
|
ct->proto.dccp.state = new_state;
|
|
spin_unlock_bh(&ct->lock);
|
|
|
|
if (new_state != old_state)
|
|
nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
|
|
|
|
nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[new_state]);
|
|
|
|
return NF_ACCEPT;
|
|
}
|
|
|
|
static int dccp_error(struct net *net, struct nf_conn *tmpl,
|
|
struct sk_buff *skb, unsigned int dataoff,
|
|
enum ip_conntrack_info *ctinfo,
|
|
u_int8_t pf, unsigned int hooknum)
|
|
{
|
|
struct dccp_hdr _dh, *dh;
|
|
unsigned int dccp_len = skb->len - dataoff;
|
|
unsigned int cscov;
|
|
const char *msg;
|
|
|
|
dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
|
|
if (dh == NULL) {
|
|
msg = "nf_ct_dccp: short packet ";
|
|
goto out_invalid;
|
|
}
|
|
|
|
if (dh->dccph_doff * 4 < sizeof(struct dccp_hdr) ||
|
|
dh->dccph_doff * 4 > dccp_len) {
|
|
msg = "nf_ct_dccp: truncated/malformed packet ";
|
|
goto out_invalid;
|
|
}
|
|
|
|
cscov = dccp_len;
|
|
if (dh->dccph_cscov) {
|
|
cscov = (dh->dccph_cscov - 1) * 4;
|
|
if (cscov > dccp_len) {
|
|
msg = "nf_ct_dccp: bad checksum coverage ";
|
|
goto out_invalid;
|
|
}
|
|
}
|
|
|
|
if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
|
|
nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_DCCP,
|
|
pf)) {
|
|
msg = "nf_ct_dccp: bad checksum ";
|
|
goto out_invalid;
|
|
}
|
|
|
|
if (dh->dccph_type >= DCCP_PKT_INVALID) {
|
|
msg = "nf_ct_dccp: reserved packet type ";
|
|
goto out_invalid;
|
|
}
|
|
|
|
return NF_ACCEPT;
|
|
|
|
out_invalid:
|
|
if (LOG_INVALID(net, IPPROTO_DCCP))
|
|
nf_log_packet(pf, 0, skb, NULL, NULL, NULL, msg);
|
|
return -NF_ACCEPT;
|
|
}
|
|
|
|
static int dccp_print_tuple(struct seq_file *s,
|
|
const struct nf_conntrack_tuple *tuple)
|
|
{
|
|
return seq_printf(s, "sport=%hu dport=%hu ",
|
|
ntohs(tuple->src.u.dccp.port),
|
|
ntohs(tuple->dst.u.dccp.port));
|
|
}
|
|
|
|
static int dccp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
|
|
{
|
|
return seq_printf(s, "%s ", dccp_state_names[ct->proto.dccp.state]);
|
|
}
|
|
|
|
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
|
|
static int dccp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
|
|
struct nf_conn *ct)
|
|
{
|
|
struct nlattr *nest_parms;
|
|
|
|
spin_lock_bh(&ct->lock);
|
|
nest_parms = nla_nest_start(skb, CTA_PROTOINFO_DCCP | NLA_F_NESTED);
|
|
if (!nest_parms)
|
|
goto nla_put_failure;
|
|
if (nla_put_u8(skb, CTA_PROTOINFO_DCCP_STATE, ct->proto.dccp.state) ||
|
|
nla_put_u8(skb, CTA_PROTOINFO_DCCP_ROLE,
|
|
ct->proto.dccp.role[IP_CT_DIR_ORIGINAL]) ||
|
|
nla_put_be64(skb, CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ,
|
|
cpu_to_be64(ct->proto.dccp.handshake_seq)))
|
|
goto nla_put_failure;
|
|
nla_nest_end(skb, nest_parms);
|
|
spin_unlock_bh(&ct->lock);
|
|
return 0;
|
|
|
|
nla_put_failure:
|
|
spin_unlock_bh(&ct->lock);
|
|
return -1;
|
|
}
|
|
|
|
static const struct nla_policy dccp_nla_policy[CTA_PROTOINFO_DCCP_MAX + 1] = {
|
|
[CTA_PROTOINFO_DCCP_STATE] = { .type = NLA_U8 },
|
|
[CTA_PROTOINFO_DCCP_ROLE] = { .type = NLA_U8 },
|
|
[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ] = { .type = NLA_U64 },
|
|
};
|
|
|
|
static int nlattr_to_dccp(struct nlattr *cda[], struct nf_conn *ct)
|
|
{
|
|
struct nlattr *attr = cda[CTA_PROTOINFO_DCCP];
|
|
struct nlattr *tb[CTA_PROTOINFO_DCCP_MAX + 1];
|
|
int err;
|
|
|
|
if (!attr)
|
|
return 0;
|
|
|
|
err = nla_parse_nested(tb, CTA_PROTOINFO_DCCP_MAX, attr,
|
|
dccp_nla_policy);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
if (!tb[CTA_PROTOINFO_DCCP_STATE] ||
|
|
!tb[CTA_PROTOINFO_DCCP_ROLE] ||
|
|
nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) > CT_DCCP_ROLE_MAX ||
|
|
nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]) >= CT_DCCP_IGNORE) {
|
|
return -EINVAL;
|
|
}
|
|
|
|
spin_lock_bh(&ct->lock);
|
|
ct->proto.dccp.state = nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]);
|
|
if (nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) == CT_DCCP_ROLE_CLIENT) {
|
|
ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT;
|
|
ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER;
|
|
} else {
|
|
ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_SERVER;
|
|
ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_CLIENT;
|
|
}
|
|
if (tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]) {
|
|
ct->proto.dccp.handshake_seq =
|
|
be64_to_cpu(nla_get_be64(tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]));
|
|
}
|
|
spin_unlock_bh(&ct->lock);
|
|
return 0;
|
|
}
|
|
|
|
static int dccp_nlattr_size(void)
|
|
{
|
|
return nla_total_size(0) /* CTA_PROTOINFO_DCCP */
|
|
+ nla_policy_len(dccp_nla_policy, CTA_PROTOINFO_DCCP_MAX + 1);
|
|
}
|
|
|
|
#endif
|
|
|
|
#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
|
|
|
|
#include <linux/netfilter/nfnetlink.h>
|
|
#include <linux/netfilter/nfnetlink_cttimeout.h>
|
|
|
|
static int dccp_timeout_nlattr_to_obj(struct nlattr *tb[],
|
|
struct net *net, void *data)
|
|
{
|
|
struct dccp_net *dn = dccp_pernet(net);
|
|
unsigned int *timeouts = data;
|
|
int i;
|
|
|
|
/* set default DCCP timeouts. */
|
|
for (i=0; i<CT_DCCP_MAX; i++)
|
|
timeouts[i] = dn->dccp_timeout[i];
|
|
|
|
/* there's a 1:1 mapping between attributes and protocol states. */
|
|
for (i=CTA_TIMEOUT_DCCP_UNSPEC+1; i<CTA_TIMEOUT_DCCP_MAX+1; i++) {
|
|
if (tb[i]) {
|
|
timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
dccp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
|
|
{
|
|
const unsigned int *timeouts = data;
|
|
int i;
|
|
|
|
for (i=CTA_TIMEOUT_DCCP_UNSPEC+1; i<CTA_TIMEOUT_DCCP_MAX+1; i++) {
|
|
if (nla_put_be32(skb, i, htonl(timeouts[i] / HZ)))
|
|
goto nla_put_failure;
|
|
}
|
|
return 0;
|
|
|
|
nla_put_failure:
|
|
return -ENOSPC;
|
|
}
|
|
|
|
static const struct nla_policy
|
|
dccp_timeout_nla_policy[CTA_TIMEOUT_DCCP_MAX+1] = {
|
|
[CTA_TIMEOUT_DCCP_REQUEST] = { .type = NLA_U32 },
|
|
[CTA_TIMEOUT_DCCP_RESPOND] = { .type = NLA_U32 },
|
|
[CTA_TIMEOUT_DCCP_PARTOPEN] = { .type = NLA_U32 },
|
|
[CTA_TIMEOUT_DCCP_OPEN] = { .type = NLA_U32 },
|
|
[CTA_TIMEOUT_DCCP_CLOSEREQ] = { .type = NLA_U32 },
|
|
[CTA_TIMEOUT_DCCP_CLOSING] = { .type = NLA_U32 },
|
|
[CTA_TIMEOUT_DCCP_TIMEWAIT] = { .type = NLA_U32 },
|
|
};
|
|
#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
|
|
|
|
#ifdef CONFIG_SYSCTL
|
|
/* template, data assigned later */
|
|
static struct ctl_table dccp_sysctl_table[] = {
|
|
{
|
|
.procname = "nf_conntrack_dccp_timeout_request",
|
|
.maxlen = sizeof(unsigned int),
|
|
.mode = 0644,
|
|
.proc_handler = proc_dointvec_jiffies,
|
|
},
|
|
{
|
|
.procname = "nf_conntrack_dccp_timeout_respond",
|
|
.maxlen = sizeof(unsigned int),
|
|
.mode = 0644,
|
|
.proc_handler = proc_dointvec_jiffies,
|
|
},
|
|
{
|
|
.procname = "nf_conntrack_dccp_timeout_partopen",
|
|
.maxlen = sizeof(unsigned int),
|
|
.mode = 0644,
|
|
.proc_handler = proc_dointvec_jiffies,
|
|
},
|
|
{
|
|
.procname = "nf_conntrack_dccp_timeout_open",
|
|
.maxlen = sizeof(unsigned int),
|
|
.mode = 0644,
|
|
.proc_handler = proc_dointvec_jiffies,
|
|
},
|
|
{
|
|
.procname = "nf_conntrack_dccp_timeout_closereq",
|
|
.maxlen = sizeof(unsigned int),
|
|
.mode = 0644,
|
|
.proc_handler = proc_dointvec_jiffies,
|
|
},
|
|
{
|
|
.procname = "nf_conntrack_dccp_timeout_closing",
|
|
.maxlen = sizeof(unsigned int),
|
|
.mode = 0644,
|
|
.proc_handler = proc_dointvec_jiffies,
|
|
},
|
|
{
|
|
.procname = "nf_conntrack_dccp_timeout_timewait",
|
|
.maxlen = sizeof(unsigned int),
|
|
.mode = 0644,
|
|
.proc_handler = proc_dointvec_jiffies,
|
|
},
|
|
{
|
|
.procname = "nf_conntrack_dccp_loose",
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = proc_dointvec,
|
|
},
|
|
{ }
|
|
};
|
|
#endif /* CONFIG_SYSCTL */
|
|
|
|
static int dccp_kmemdup_sysctl_table(struct net *net, struct nf_proto_net *pn,
|
|
struct dccp_net *dn)
|
|
{
|
|
#ifdef CONFIG_SYSCTL
|
|
if (pn->ctl_table)
|
|
return 0;
|
|
|
|
pn->ctl_table = kmemdup(dccp_sysctl_table,
|
|
sizeof(dccp_sysctl_table),
|
|
GFP_KERNEL);
|
|
if (!pn->ctl_table)
|
|
return -ENOMEM;
|
|
|
|
pn->ctl_table[0].data = &dn->dccp_timeout[CT_DCCP_REQUEST];
|
|
pn->ctl_table[1].data = &dn->dccp_timeout[CT_DCCP_RESPOND];
|
|
pn->ctl_table[2].data = &dn->dccp_timeout[CT_DCCP_PARTOPEN];
|
|
pn->ctl_table[3].data = &dn->dccp_timeout[CT_DCCP_OPEN];
|
|
pn->ctl_table[4].data = &dn->dccp_timeout[CT_DCCP_CLOSEREQ];
|
|
pn->ctl_table[5].data = &dn->dccp_timeout[CT_DCCP_CLOSING];
|
|
pn->ctl_table[6].data = &dn->dccp_timeout[CT_DCCP_TIMEWAIT];
|
|
pn->ctl_table[7].data = &dn->dccp_loose;
|
|
|
|
/* Don't export sysctls to unprivileged users */
|
|
if (net->user_ns != &init_user_ns)
|
|
pn->ctl_table[0].procname = NULL;
|
|
#endif
|
|
return 0;
|
|
}
|
|
|
|
static int dccp_init_net(struct net *net, u_int16_t proto)
|
|
{
|
|
struct dccp_net *dn = dccp_pernet(net);
|
|
struct nf_proto_net *pn = &dn->pn;
|
|
|
|
if (!pn->users) {
|
|
/* default values */
|
|
dn->dccp_loose = 1;
|
|
dn->dccp_timeout[CT_DCCP_REQUEST] = 2 * DCCP_MSL;
|
|
dn->dccp_timeout[CT_DCCP_RESPOND] = 4 * DCCP_MSL;
|
|
dn->dccp_timeout[CT_DCCP_PARTOPEN] = 4 * DCCP_MSL;
|
|
dn->dccp_timeout[CT_DCCP_OPEN] = 12 * 3600 * HZ;
|
|
dn->dccp_timeout[CT_DCCP_CLOSEREQ] = 64 * HZ;
|
|
dn->dccp_timeout[CT_DCCP_CLOSING] = 64 * HZ;
|
|
dn->dccp_timeout[CT_DCCP_TIMEWAIT] = 2 * DCCP_MSL;
|
|
}
|
|
|
|
return dccp_kmemdup_sysctl_table(net, pn, dn);
|
|
}
|
|
|
|
static struct nf_conntrack_l4proto dccp_proto4 __read_mostly = {
|
|
.l3proto = AF_INET,
|
|
.l4proto = IPPROTO_DCCP,
|
|
.name = "dccp",
|
|
.pkt_to_tuple = dccp_pkt_to_tuple,
|
|
.invert_tuple = dccp_invert_tuple,
|
|
.new = dccp_new,
|
|
.packet = dccp_packet,
|
|
.get_timeouts = dccp_get_timeouts,
|
|
.error = dccp_error,
|
|
.print_tuple = dccp_print_tuple,
|
|
.print_conntrack = dccp_print_conntrack,
|
|
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
|
|
.to_nlattr = dccp_to_nlattr,
|
|
.nlattr_size = dccp_nlattr_size,
|
|
.from_nlattr = nlattr_to_dccp,
|
|
.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
|
|
.nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
|
|
.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
|
|
.nla_policy = nf_ct_port_nla_policy,
|
|
#endif
|
|
#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
|
|
.ctnl_timeout = {
|
|
.nlattr_to_obj = dccp_timeout_nlattr_to_obj,
|
|
.obj_to_nlattr = dccp_timeout_obj_to_nlattr,
|
|
.nlattr_max = CTA_TIMEOUT_DCCP_MAX,
|
|
.obj_size = sizeof(unsigned int) * CT_DCCP_MAX,
|
|
.nla_policy = dccp_timeout_nla_policy,
|
|
},
|
|
#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
|
|
.net_id = &dccp_net_id,
|
|
.init_net = dccp_init_net,
|
|
};
|
|
|
|
static struct nf_conntrack_l4proto dccp_proto6 __read_mostly = {
|
|
.l3proto = AF_INET6,
|
|
.l4proto = IPPROTO_DCCP,
|
|
.name = "dccp",
|
|
.pkt_to_tuple = dccp_pkt_to_tuple,
|
|
.invert_tuple = dccp_invert_tuple,
|
|
.new = dccp_new,
|
|
.packet = dccp_packet,
|
|
.get_timeouts = dccp_get_timeouts,
|
|
.error = dccp_error,
|
|
.print_tuple = dccp_print_tuple,
|
|
.print_conntrack = dccp_print_conntrack,
|
|
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
|
|
.to_nlattr = dccp_to_nlattr,
|
|
.nlattr_size = dccp_nlattr_size,
|
|
.from_nlattr = nlattr_to_dccp,
|
|
.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
|
|
.nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
|
|
.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
|
|
.nla_policy = nf_ct_port_nla_policy,
|
|
#endif
|
|
#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
|
|
.ctnl_timeout = {
|
|
.nlattr_to_obj = dccp_timeout_nlattr_to_obj,
|
|
.obj_to_nlattr = dccp_timeout_obj_to_nlattr,
|
|
.nlattr_max = CTA_TIMEOUT_DCCP_MAX,
|
|
.obj_size = sizeof(unsigned int) * CT_DCCP_MAX,
|
|
.nla_policy = dccp_timeout_nla_policy,
|
|
},
|
|
#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
|
|
.net_id = &dccp_net_id,
|
|
.init_net = dccp_init_net,
|
|
};
|
|
|
|
static __net_init int dccp_net_init(struct net *net)
|
|
{
|
|
int ret = 0;
|
|
ret = nf_conntrack_l4proto_register(net,
|
|
&dccp_proto4);
|
|
if (ret < 0) {
|
|
pr_err("nf_conntrack_l4proto_dccp4 :protocol register failed.\n");
|
|
goto out;
|
|
}
|
|
ret = nf_conntrack_l4proto_register(net,
|
|
&dccp_proto6);
|
|
if (ret < 0) {
|
|
pr_err("nf_conntrack_l4proto_dccp6 :protocol register failed.\n");
|
|
goto cleanup_dccp4;
|
|
}
|
|
return 0;
|
|
cleanup_dccp4:
|
|
nf_conntrack_l4proto_unregister(net,
|
|
&dccp_proto4);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static __net_exit void dccp_net_exit(struct net *net)
|
|
{
|
|
nf_conntrack_l4proto_unregister(net,
|
|
&dccp_proto6);
|
|
nf_conntrack_l4proto_unregister(net,
|
|
&dccp_proto4);
|
|
}
|
|
|
|
static struct pernet_operations dccp_net_ops = {
|
|
.init = dccp_net_init,
|
|
.exit = dccp_net_exit,
|
|
.id = &dccp_net_id,
|
|
.size = sizeof(struct dccp_net),
|
|
};
|
|
|
|
static int __init nf_conntrack_proto_dccp_init(void)
|
|
{
|
|
return register_pernet_subsys(&dccp_net_ops);
|
|
}
|
|
|
|
static void __exit nf_conntrack_proto_dccp_fini(void)
|
|
{
|
|
unregister_pernet_subsys(&dccp_net_ops);
|
|
}
|
|
|
|
module_init(nf_conntrack_proto_dccp_init);
|
|
module_exit(nf_conntrack_proto_dccp_fini);
|
|
|
|
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
|
|
MODULE_DESCRIPTION("DCCP connection tracking protocol helper");
|
|
MODULE_LICENSE("GPL");
|