kernel.git/net/dccp/minisocks.c, branch linux-3.18.y

dccp: Unlock sock before calling sk_free()

2017-04-18T05:55:52Z

commit d5afb6f9b6bb2c57bd0c05e76e12489dc0d037d9 upstream. The code where sk_clone() came from created a new socket and locked it, but then, on the error path didn't unlock it. This problem stayed there for a long while, till b0691c8ee7c2 ("net: Unlock sock before calling sk_free()") fixed it, but unfortunately the callers of sk_clone() (now sk_clone_locked()) were not audited and the one in dccp_create_openreq_child() remained. Now in the age of the syskaller fuzzer, this was finally uncovered, as reported by Dmitry: ---- 8< ---- I've got the following report while running syzkaller fuzzer on 86292b33d4b7 ("Merge branch 'akpm' (patches from Andrew)") [ BUG: held lock freed! ] 4.10.0+ #234 Not tainted ------------------------- syz-executor6/6898 is freeing memory ffff88006286cac0-ffff88006286d3b7, with a lock still held there! (slock-AF_INET6){+.-...}, at: [] spin_lock include/linux/spinlock.h:299 [inline] (slock-AF_INET6){+.-...}, at: [] sk_clone_lock+0x3d9/0x12c0 net/core/sock.c:1504 5 locks held by syz-executor6/6898: #0: (sk_lock-AF_INET6){+.+.+.}, at: [] lock_sock include/net/sock.h:1460 [inline] #0: (sk_lock-AF_INET6){+.+.+.}, at: [] inet_stream_connect+0x44/0xa0 net/ipv4/af_inet.c:681 #1: (rcu_read_lock){......}, at: [] inet6_csk_xmit+0x12a/0x5d0 net/ipv6/inet6_connection_sock.c:126 #2: (rcu_read_lock){......}, at: [] __skb_unlink include/linux/skbuff.h:1767 [inline] #2: (rcu_read_lock){......}, at: [] __skb_dequeue include/linux/skbuff.h:1783 [inline] #2: (rcu_read_lock){......}, at: [] process_backlog+0x264/0x730 net/core/dev.c:4835 #3: (rcu_read_lock){......}, at: [] ip6_input_finish+0x0/0x1700 net/ipv6/ip6_input.c:59 #4: (slock-AF_INET6){+.-...}, at: [] spin_lock include/linux/spinlock.h:299 [inline] #4: (slock-AF_INET6){+.-...}, at: [] sk_clone_lock+0x3d9/0x12c0 net/core/sock.c:1504 Fix it just like was done by b0691c8ee7c2 ("net: Unlock sock before calling sk_free()"). Reported-by: Dmitry Vyukov Cc: Cong Wang Cc: Eric Dumazet Cc: Gerrit Renker Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170301153510.GE15145@kernel.org Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

inet: move ipv6only in sock_common

2014-07-02T06:46:21Z

When an UDP application switches from AF_INET to AF_INET6 sockets, we have a small performance degradation for IPv4 communications because of extra cache line misses to access ipv6only information. This can also be noticed for TCP listeners, as ipv6_only_sock() is also used from __inet_lookup_listener()->compute_score() This is magnified when SO_REUSEPORT is used. Move ipv6only into struct sock_common so that it is available at no extra cost in lookups. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: Fix use after free by removing length arg from sk_data_ready callbacks.

2014-04-11T20:15:36Z

Several spots in the kernel perform a sequence like: skb_queue_tail(&sk->s_receive_queue, skb); sk->sk_data_ready(sk, skb->len); But at the moment we place the SKB onto the socket receive queue it can be consumed and freed up. So this skb->len access is potentially to freed up memory. Furthermore, the skb->len can be modified by the consumer so it is possible that the value isn't accurate. And finally, no actual implementation of this callback actually uses the length argument. And since nobody actually cared about it's value, lots of call sites pass arbitrary values in such as '0' and even '1'. So just remove the length argument from the callback, that way there is no confusion whatsoever and all of these use-after-free cases get fixed as a side effect. Based upon a patch by Eric Dumazet and his suggestion to audit this issue tree-wide. Signed-off-by: David S. Miller

inet: rename ir_loc_port to ir_num

2013-10-10T18:37:35Z

In commit 634fb979e8f ("inet: includes a sock_common in request_sock") I forgot that the two ports in sock_common do not have same byte order : skc_dport is __be16 (network order), but skc_num is __u16 (host order) So sparse complains because ir_loc_port (mapped into skc_num) is considered as __u16 while it should be __be16 Let rename ir_loc_port to ireq->ir_num (analogy with inet->inet_num), and perform appropriate htons/ntohs conversions. Signed-off-by: Eric Dumazet Reported-by: Wu Fengguang Signed-off-by: David S. Miller

inet: includes a sock_common in request_sock

2013-10-10T04:08:07Z

TCP listener refactoring, part 5 : We want to be able to insert request sockets (SYN_RECV) into main ehash table instead of the per listener hash table to allow RCU lookups and remove listener lock contention. This patch includes the needed struct sock_common in front of struct request_sock This means there is no more inet6_request_sock IPv6 specific structure. Following inet_request_sock fields were renamed as they became macros to reference fields from struct sock_common. Prefix ir_ was chosen to avoid name collisions. loc_port -> ir_loc_port loc_addr -> ir_loc_addr rmt_addr -> ir_rmt_addr rmt_port -> ir_rmt_port iif -> ir_iif Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

ipv6: make lookups simpler and faster

2013-10-09T04:01:25Z

TCP listener refactoring, part 4 : To speed up inet lookups, we moved IPv4 addresses from inet to struct sock_common Now is time to do the same for IPv6, because it permits us to have fast lookups for all kind of sockets, including upcoming SYN_RECV. Getting IPv6 addresses in TCP lookups currently requires two extra cache lines, plus a dereference (and memory stall). inet6_sk(sk) does the dereference of inet_sk(__sk)->pinet6 This patch is way bigger than its IPv4 counter part, because for IPv4, we could add aliases (inet_daddr, inet_rcv_saddr), while on IPv6, it's not doable easily. inet6_sk(sk)->daddr becomes sk->sk_v6_daddr inet6_sk(sk)->rcv_saddr becomes sk->sk_v6_rcv_saddr And timewait socket also have tw->tw_v6_daddr & tw->tw_v6_rcv_saddr at the same offset. We get rid of INET6_TW_MATCH() as INET6_MATCH() is now the generic macro. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

tcp: better retrans tracking for defer-accept

2012-11-03T18:45:00Z

For passive TCP connections using TCP_DEFER_ACCEPT facility, we incorrectly increment req->retrans each time timeout triggers while no SYNACK is sent. SYNACK are not sent for TCP_DEFER_ACCEPT that were established (for which we received the ACK from client). Only the last SYNACK is sent so that we can receive again an ACK from client, to move the req into accept queue. We plan to change this later to avoid the useless retransmit (and potential problem as this SYNACK could be lost) TCP_INFO later gives wrong information to user, claiming imaginary retransmits. Decouple req->retrans field into two independent fields : num_retrans : number of retransmit num_timeout : number of timeouts num_timeout is the counter that is incremented at each timeout, regardless of actual SYNACK being sent or not, and used to compute the exponential timeout. Introduce inet_rtx_syn_ack() helper to increment num_retrans only if ->rtx_syn_ack() succeeded. Use inet_rtx_syn_ack() from tcp_check_req() to increment num_retrans when we re-send a SYNACK in answer to a (retransmitted) SYN. Prior to this patch, we were not counting these retransmits. Change tcp_v[46]_rtx_synack() to increment TCP_MIB_RETRANSSEGS only if a synack packet was successfully queued. Reported-by: Yuchung Cheng Signed-off-by: Eric Dumazet Cc: Julian Anastasov Cc: Vijay Subramanian Cc: Elliott Hughes Cc: Neal Cardwell Signed-off-by: David S. Miller

dccp: fix bug in sequence number validation during connection setup

2012-03-03T16:02:52Z

This fixes a bug in the sequence number validation during the initial handshake. The code did not treat the initial sequence numbers ISS and ISR as read-only and did not keep state for GSR and GSS as required by the specification. This causes problems with retransmissions during the initial handshake, causing the budding connection to be reset. This patch now treats ISS/ISR as read-only and tracks GSS/GSR as required. Signed-off-by: Samuel Jero Signed-off-by: Gerrit Renker

net: use IS_ENABLED(CONFIG_IPV6)

2011-12-11T23:25:16Z

Instead of testing defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: remove ipv6_addr_copy()

2011-11-22T21:43:32Z

C assignment can handle struct in6_addr copying. Signed-off-by: Alexey Dobriyan Signed-off-by: David S. Miller