kernel.git/include/net/sctp/sm.h, branch linux-3.2.y

net: sctp: fix skb_over_panic when receiving malformed ASCONF chunks

2014-11-05T20:27:48Z

commit 9de7922bc709eee2f609cd01d98aaedc4cf5ea74 upstream. Commit 6f4c618ddb0 ("SCTP : Add paramters validity check for ASCONF chunk") added basic verification of ASCONF chunks, however, it is still possible to remotely crash a server by sending a special crafted ASCONF chunk, even up to pre 2.6.12 kernels: skb_over_panic: text:ffffffffa01ea1c3 len:31056 put:30768 head:ffff88011bd81800 data:ffff88011bd81800 tail:0x7950 end:0x440 dev: ------------[ cut here ]------------ kernel BUG at net/core/skbuff.c:129! [...] Call Trace: [] skb_put+0x5c/0x70 [] sctp_addto_chunk+0x63/0xd0 [sctp] [] sctp_process_asconf+0x1af/0x540 [sctp] [] ? _read_unlock_bh+0x15/0x20 [] sctp_sf_do_asconf+0x168/0x240 [sctp] [] sctp_do_sm+0x71/0x1210 [sctp] [] ? fib_rules_lookup+0xad/0xf0 [] ? sctp_cmp_addr_exact+0x32/0x40 [sctp] [] sctp_assoc_bh_rcv+0xd3/0x180 [sctp] [] sctp_inq_push+0x56/0x80 [sctp] [] sctp_rcv+0x982/0xa10 [sctp] [] ? ipt_local_in_hook+0x23/0x28 [iptable_filter] [] ? nf_iterate+0x69/0xb0 [] ? ip_local_deliver_finish+0x0/0x2d0 [] ? nf_hook_slow+0x76/0x120 [] ? ip_local_deliver_finish+0x0/0x2d0 [] ip_local_deliver_finish+0xdd/0x2d0 [] ip_local_deliver+0x98/0xa0 [] ip_rcv_finish+0x12d/0x440 [] ip_rcv+0x275/0x350 [] __netif_receive_skb+0x4ab/0x750 [] netif_receive_skb+0x58/0x60 This can be triggered e.g., through a simple scripted nmap connection scan injecting the chunk after the handshake, for example, ... -------------- INIT[ASCONF; ASCONF_ACK] -------------> <----------- INIT-ACK[ASCONF; ASCONF_ACK] ------------ -------------------- COOKIE-ECHO --------------------> <-------------------- COOKIE-ACK --------------------- ------------------ ASCONF; UNKNOWN ------------------> ... where ASCONF chunk of length 280 contains 2 parameters ... 1) Add IP address parameter (param length: 16) 2) Add/del IP address parameter (param length: 255) ... followed by an UNKNOWN chunk of e.g. 4 bytes. Here, the Address Parameter in the ASCONF chunk is even missing, too. This is just an example and similarly-crafted ASCONF chunks could be used just as well. The ASCONF chunk passes through sctp_verify_asconf() as all parameters passed sanity checks, and after walking, we ended up successfully at the chunk end boundary, and thus may invoke sctp_process_asconf(). Parameter walking is done with WORD_ROUND() to take padding into account. In sctp_process_asconf()'s TLV processing, we may fail in sctp_process_asconf_param() e.g., due to removal of the IP address that is also the source address of the packet containing the ASCONF chunk, and thus we need to add all TLVs after the failure to our ASCONF response to remote via helper function sctp_add_asconf_response(), which basically invokes a sctp_addto_chunk() adding the error parameters to the given skb. When walking to the next parameter this time, we proceed with ... length = ntohs(asconf_param->param_hdr.length); asconf_param = (void *)asconf_param + length; ... instead of the WORD_ROUND()'ed length, thus resulting here in an off-by-one that leads to reading the follow-up garbage parameter length of 12336, and thus throwing an skb_over_panic for the reply when trying to sctp_addto_chunk() next time, which implicitly calls the skb_put() with that length. Fix it by using sctp_walk_params() [ which is also used in INIT parameter processing ] macro in the verification *and* in ASCONF processing: it will make sure we don't spill over, that we walk parameters WORD_ROUND()'ed. Moreover, we're being more defensive and guard against unknown parameter types and missized addresses. Joint work with Vlad Yasevich. Fixes: b896b82be4ae ("[SCTP] ADDIP: Support for processing incoming ASCONF_ACK chunks.") Signed-off-by: Daniel Borkmann Signed-off-by: Vlad Yasevich Acked-by: Neil Horman Signed-off-by: David S. Miller [bwh: Backported to 3.2: - Adjust context - sctp_sf_violation_paramlen() doesn't take a struct net * parameter] Signed-off-by: Ben Hutchings

sctp: implement event notification SCTP_SENDER_DRY_EVENT

2011-04-21T17:35:44Z

This patch implement event notification SCTP_SENDER_DRY_EVENT. SCTP Socket API Extensions: 6.1.9. SCTP_SENDER_DRY_EVENT When the SCTP stack has no more user data to send or retransmit, this notification is given to the user. Also, at the time when a user app subscribes to this event, if there is no data to be sent or retransmit, the stack will immediately send up this notification. Signed-off-by: Wei Yongjun Signed-off-by: Vlad Yasevich Signed-off-by: David S. Miller

sctp: make heartbeat information in sctp_make_heartbeat()

2011-04-20T08:51:05Z

Make heartbeat information in sctp_make_heartbeat() instead of make it in sctp_sf_heartbeat() directly for common using. Signed-off-by: Wei Yongjun Signed-off-by: Vlad Yasevich Signed-off-by: David S. Miller

net: return operator cleanup

2010-09-23T21:33:39Z

Change "return (EXPR);" to "return EXPR;" return is not a function, parentheses are not required. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6

2010-05-12T07:05:35Z

Conflicts: Documentation/feature-removal-schedule.txt drivers/net/wireless/ath/ar9170/usb.c drivers/scsi/iscsi_tcp.c net/ipv4/ipmr.c

sctp: Fix a race between ICMP protocol unreachable and connect()

2010-05-06T07:56:07Z

ICMP protocol unreachable handling completely disregarded the fact that the user may have locked the socket. It proceeded to destroy the association, even though the user may have held the lock and had a ref on the association. This resulted in the following: Attempt to release alive inet socket f6afcc00 ========================= [ BUG: held lock freed! ] ------------------------- somenu/2672 is freeing memory f6afcc00-f6afcfff, with a lock still held there! (sk_lock-AF_INET){+.+.+.}, at: [] sctp_connect+0x13/0x4c 1 lock held by somenu/2672: #0: (sk_lock-AF_INET){+.+.+.}, at: [] sctp_connect+0x13/0x4c stack backtrace: Pid: 2672, comm: somenu Not tainted 2.6.32-telco #55 Call Trace: [] ? printk+0xf/0x11 [] debug_check_no_locks_freed+0xce/0xff [] kmem_cache_free+0x21/0x66 [] __sk_free+0x9d/0xab [] sk_free+0x1c/0x1e [] sctp_association_put+0x32/0x89 [] __sctp_connect+0x36d/0x3f4 [] ? sctp_connect+0x13/0x4c [] ? autoremove_wake_function+0x0/0x33 [] sctp_connect+0x31/0x4c [] inet_dgram_connect+0x4b/0x55 [] sys_connect+0x54/0x71 [] ? lock_release_non_nested+0x88/0x239 [] ? might_fault+0x42/0x7c [] ? might_fault+0x42/0x7c [] sys_socketcall+0x6d/0x178 [] ? trace_hardirqs_on_thunk+0xc/0x10 [] syscall_call+0x7/0xb This was because the sctp_wait_for_connect() would aqcure the socket lock and then proceed to release the last reference count on the association, thus cause the fully destruction path to finish freeing the socket. The simplest solution is to start a very short timer in case the socket is owned by user. When the timer expires, we can do some verification and be able to do the release properly. Signed-off-by: Vlad Yasevich Signed-off-by: David S. Miller

sctp: discard ABORT chunk with zero verification tag in COOKIE-WAIT state

2010-05-01T01:42:44Z

In current implementation if ABORT chunk is received with T flag is set and zero verification tag in COOKIE-WAIT state, the ABORT chunk will be always accepted. This is because in COOKIE-WAIT state, the endpoint does not know the peer's verification tag, and it's zero in the endpoint. Signed-off-by: Wei Yongjun Signed-off-by: Vlad Yasevich

sctp: Fix malformed "Invalid Stream Identifier" error

2009-11-23T20:53:56Z

The "Invalid Stream Identifier" error has a 16 bit reserved field at the end, thus making the parameter length be 8 bytes. We've never supplied that reserved field making wireshark tag the packet as malformed. Reported-by: Chris Dischino Signed-off-by: Vlad Yasevich

sctp: Fix to handle SHUTDOWN in SHUTDOWN_RECEIVED state

2008-10-23T08:01:18Z

Once an endpoint has reached the SHUTDOWN-RECEIVED state, it MUST NOT send a SHUTDOWN in response to a ULP request. The Cumulative TSN Ack of the received SHUTDOWN chunk MUST be processed. This patch fix to process Cumulative TSN Ack of the received SHUTDOWN chunk in SHUTDOWN_RECEIVED state. Signed-off-by: Wei Yongjun Signed-off-by: Vlad Yasevich Signed-off-by: David S. Miller

sctp: Fix kernel panic while process protocol violation parameter

2008-09-30T12:32:24Z

Since call to function sctp_sf_abort_violation() need paramter 'arg' with 'struct sctp_chunk' type, it will read the chunk type and chunk length from the chunk_hdr member of chunk. But call to sctp_sf_violation_paramlen() always with 'struct sctp_paramhdr' type's parameter, it will be passed to sctp_sf_abort_violation(). This may cause kernel panic. sctp_sf_violation_paramlen() |-- sctp_sf_abort_violation() |-- sctp_make_abort_violation() This patch fixed this problem. This patch also fix two place which called sctp_sf_violation_paramlen() with wrong paramter type. Signed-off-by: Wei Yongjun Signed-off-by: Vlad Yasevich Signed-off-by: David S. Miller