BMC/Intel-BMC/linux.git/net/sctp/sm_make_chunk.c, branch dev

sctp: asconf's process should verify address parameter is in the beginning

2015-08-27T20:59:33+00:00

in sctp_process_asconf(), we get address parameter from the beginning of the addip params. but we never check if it's really there. if the addr param is not there, it still can pass sctp_verify_asconf(), then to be handled by sctp_process_asconf(), it will not be safe. so add a code in sctp_verify_asconf() to check the address parameter is in the beginning, or return false to send abort. note that this can also detect multiple address parameters, and reject it. Signed-off-by: Xin Long Signed-off-by: Marcelo Ricardo Leitner Acked-by: Vlad Yasevich Signed-off-by: David S. Miller

net: sctp: fix passing wrong parameter header to param_type2af in sctp_process_param

2015-01-31T01:45:23+00:00

When making use of RFC5061, section 4.2.4. for setting the primary IP address, we're passing a wrong parameter header to param_type2af(), resulting always in NULL being returned. At this point, param.p points to a sctp_addip_param struct, containing a sctp_paramhdr (type = 0xc004, length = var), and crr_id as a correlation id. Followed by that, as also presented in RFC5061 section 4.2.4., comes the actual sctp_addr_param, which also contains a sctp_paramhdr, but this time with the correct type SCTP_PARAM_IPV{4,6}_ADDRESS that param_type2af() can make use of. Since we already hold a pointer to addr_param from previous line, just reuse it for param_type2af(). Fixes: d6de3097592b ("[SCTP]: Add the handling of "Set Primary IP Address" parameter to INIT") Signed-off-by: Saran Maruti Ramanara Signed-off-by: Daniel Borkmann Acked-by: Vlad Yasevich Acked-by: Neil Horman Signed-off-by: David S. Miller

switch sctp_user_addto_chunk() and sctp_datamsg_from_user() to passing iov_iter

2014-11-24T10:16:40+00:00

Signed-off-by: Al Viro

new helper: memcpy_from_msg()

2014-11-24T09:28:48+00:00

Signed-off-by: Al Viro

net: sctp: fix NULL pointer dereference in af->from_addr_param on malformed packet

2014-11-11T20:19:10+00:00

An SCTP server doing ASCONF will panic on malformed INIT ping-of-death in the form of: ------------ INIT[PARAM: SET_PRIMARY_IP] ------------> While the INIT chunk parameter verification dissects through many things in order to detect malformed input, it misses to actually check parameters inside of parameters. E.g. RFC5061, section 4.2.4 proposes a 'set primary IP address' parameter in ASCONF, which has as a subparameter an address parameter. So an attacker may send a parameter type other than SCTP_PARAM_IPV4_ADDRESS or SCTP_PARAM_IPV6_ADDRESS, param_type2af() will subsequently return 0 and thus sctp_get_af_specific() returns NULL, too, which we then happily dereference unconditionally through af->from_addr_param(). The trace for the log: BUG: unable to handle kernel NULL pointer dereference at 0000000000000078 IP: [] sctp_process_init+0x492/0x990 [sctp] PGD 0 Oops: 0000 [#1] SMP [...] Pid: 0, comm: swapper Not tainted 2.6.32-504.el6.x86_64 #1 Bochs Bochs RIP: 0010:[] [] sctp_process_init+0x492/0x990 [sctp] [...] Call Trace: [] ? sctp_bind_addr_copy+0x5d/0xe0 [sctp] [] sctp_sf_do_5_1B_init+0x21b/0x340 [sctp] [] sctp_do_sm+0x71/0x1210 [sctp] [] ? sctp_endpoint_lookup_assoc+0xc9/0xf0 [sctp] [] sctp_endpoint_bh_rcv+0x116/0x230 [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 [...] A minimal way to address this is to check for NULL as we do on all other such occasions where we know sctp_get_af_specific() could possibly return with NULL. Fixes: d6de3097592b ("[SCTP]: Add the handling of "Set Primary IP Address" parameter to INIT") Signed-off-by: Daniel Borkmann Cc: Vlad Yasevich Acked-by: Neil Horman Signed-off-by: David S. Miller

net: sctp: fix skb_over_panic when receiving malformed ASCONF chunks

2014-10-14T16:46:22+00:00

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

ktime: add ktime_after and ktime_before helper

2014-06-11T19:23:17+00:00

Add two minimal helper functions analogous to time_before() and time_after() that will later on both be needed by SCTP code. Signed-off-by: Daniel Borkmann Signed-off-by: David S. Miller

net: sctp: cache auth_enable per endpoint

2014-04-18T22:32:00+00:00

Currently, it is possible to create an SCTP socket, then switch auth_enable via sysctl setting to 1 and crash the system on connect: Oops[#1]: CPU: 0 PID: 0 Comm: swapper Not tainted 3.14.1-mipsgit-20140415 #1 task: ffffffff8056ce80 ti: ffffffff8055c000 task.ti: ffffffff8055c000 [...] Call Trace: [] sctp_auth_asoc_set_default_hmac+0x68/0x80 [] sctp_process_init+0x5e0/0x8a4 [] sctp_sf_do_5_1B_init+0x234/0x34c [] sctp_do_sm+0xb4/0x1e8 [] sctp_endpoint_bh_rcv+0x1c4/0x214 [] sctp_rcv+0x588/0x630 [] sctp6_rcv+0x10/0x24 [] ip6_input+0x2c0/0x440 [] __netif_receive_skb_core+0x4a8/0x564 [] process_backlog+0xb4/0x18c [] net_rx_action+0x12c/0x210 [] __do_softirq+0x17c/0x2ac [] irq_exit+0x54/0xb0 [] ret_from_irq+0x0/0x4 [] rm7k_wait_irqoff+0x24/0x48 [] cpu_startup_entry+0xc0/0x148 [] start_kernel+0x37c/0x398 Code: dd0900b8 000330f8 0126302d 50c0fff1 0047182a a48306a0 03e00008 00000000 ---[ end trace b530b0551467f2fd ]--- Kernel panic - not syncing: Fatal exception in interrupt What happens while auth_enable=0 in that case is, that ep->auth_hmacs is initialized to NULL in sctp_auth_init_hmacs() when endpoint is being created. After that point, if an admin switches over to auth_enable=1, the machine can crash due to NULL pointer dereference during reception of an INIT chunk. When we enter sctp_process_init() via sctp_sf_do_5_1B_init() in order to respond to an INIT chunk, the INIT verification succeeds and while we walk and process all INIT params via sctp_process_param() we find that net->sctp.auth_enable is set, therefore do not fall through, but invoke sctp_auth_asoc_set_default_hmac() instead, and thus, dereference what we have set to NULL during endpoint initialization phase. The fix is to make auth_enable immutable by caching its value during endpoint initialization, so that its original value is being carried along until destruction. The bug seems to originate from the very first days. Fix in joint work with Daniel Borkmann. Reported-by: Joshua Kinard Signed-off-by: Vlad Yasevich Signed-off-by: Daniel Borkmann Acked-by: Neil Horman Tested-by: Joshua Kinard Signed-off-by: David S. Miller

net: sctp: fix skb leakage in COOKIE ECHO path of chunk->auth_chunk

2014-03-06T01:40:25+00:00

While working on ec0223ec48a9 ("net: sctp: fix sctp_sf_do_5_1D_ce to verify if we/peer is AUTH capable"), we noticed that there's a skb memory leakage in the error path. Running the same reproducer as in ec0223ec48a9 and by unconditionally jumping to the error label (to simulate an error condition) in sctp_sf_do_5_1D_ce() receive path lets kmemleak detector bark about the unfreed chunk->auth_chunk skb clone: Unreferenced object 0xffff8800b8f3a000 (size 256): comm "softirq", pid 0, jiffies 4294769856 (age 110.757s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 89 ab 75 5e d4 01 58 13 00 00 00 00 00 00 00 00 ..u^..X......... backtrace: [] kmemleak_alloc+0x4e/0xb0 [] kmem_cache_alloc+0xc8/0x210 [] skb_clone+0x49/0xb0 [] sctp_endpoint_bh_rcv+0x1d9/0x230 [sctp] [] sctp_inq_push+0x4c/0x70 [sctp] [] sctp_rcv+0x82e/0x9a0 [sctp] [] ip_local_deliver_finish+0xa8/0x210 [] nf_reinject+0xbf/0x180 [] nfqnl_recv_verdict+0x1d2/0x2b0 [nfnetlink_queue] [] nfnetlink_rcv_msg+0x14b/0x250 [nfnetlink] [] netlink_rcv_skb+0xa9/0xc0 [] nfnetlink_rcv+0x23f/0x408 [nfnetlink] [] netlink_unicast+0x168/0x250 [] netlink_sendmsg+0x2e1/0x3f0 [] sock_sendmsg+0x8b/0xc0 [] ___sys_sendmsg+0x369/0x380 What happens is that commit bbd0d59809f9 clones the skb containing the AUTH chunk in sctp_endpoint_bh_rcv() when having the edge case that an endpoint requires COOKIE-ECHO chunks to be authenticated: ---------- INIT[RANDOM; CHUNKS; HMAC-ALGO] ----------> <------- INIT-ACK[RANDOM; CHUNKS; HMAC-ALGO] --------- ------------------ AUTH; COOKIE-ECHO ----------------> <-------------------- COOKIE-ACK --------------------- When we enter sctp_sf_do_5_1D_ce() and before we actually get to the point where we process (and subsequently free) a non-NULL chunk->auth_chunk, we could hit the "goto nomem_init" path from an error condition and thus leave the cloned skb around w/o freeing it. The fix is to centrally free such clones in sctp_chunk_destroy() handler that is invoked from sctp_chunk_free() after all refs have dropped; and also move both kfree_skb(chunk->auth_chunk) there, so that chunk->auth_chunk is either NULL (since sctp_chunkify() allocs new chunks through kmem_cache_zalloc()) or non-NULL with a valid skb pointer. chunk->skb and chunk->auth_chunk are the only skbs in the sctp_chunk structure that need to be handeled. While at it, we should use consume_skb() for both. It is the same as dev_kfree_skb() but more appropriately named as we are not a device but a protocol. Also, this effectively replaces the kfree_skb() from both invocations into consume_skb(). Functions are the same only that kfree_skb() assumes that the frame was being dropped after a failure (e.g. for tools like drop monitor), usage of consume_skb() seems more appropriate in function sctp_chunk_destroy() though. Fixes: bbd0d59809f9 ("[SCTP]: Implement the receive and verification of AUTH chunk") Signed-off-by: Daniel Borkmann Cc: Vlad Yasevich Cc: Neil Horman Acked-by: Vlad Yasevich Acked-by: Neil Horman Signed-off-by: David S. Miller

sctp: make sctp_addto_chunk_fixed local

2014-01-13T22:42:30+00:00

Signed-off-by: Stephen Hemminger Acked-by: Neil Horman Signed-off-by: David S. Miller