From 561b1733a465cf9677356b40c27653dd45f1ac56 Mon Sep 17 00:00:00 2001 From: Wei Yongjun Date: Wed, 28 Apr 2010 08:47:18 +0000 Subject: sctp: avoid irq lock inversion while call sk->sk_data_ready() sk->sk_data_ready() of sctp socket can be called from both BH and non-BH contexts, but the default sk->sk_data_ready(), sock_def_readable(), can not be used in this case. Therefore, we have to make a new function sctp_data_ready() to grab sk->sk_data_ready() with BH disabling. ========================================================= [ INFO: possible irq lock inversion dependency detected ] 2.6.33-rc6 #129 --------------------------------------------------------- sctp_darn/1517 just changed the state of lock: (clock-AF_INET){++.?..}, at: [] sock_def_readable+0x20/0x80 but this lock took another, SOFTIRQ-unsafe lock in the past: (slock-AF_INET){+.-...} and interrupts could create inverse lock ordering between them. other info that might help us debug this: 1 lock held by sctp_darn/1517: #0: (sk_lock-AF_INET){+.+.+.}, at: [] sctp_sendmsg+0x23d/0xc00 [sctp] Signed-off-by: Wei Yongjun Signed-off-by: Vlad Yasevich Signed-off-by: David S. Miller --- include/net/sctp/sctp.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/net/sctp') diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h index 78740ec..fa6cde5 100644 --- a/include/net/sctp/sctp.h +++ b/include/net/sctp/sctp.h @@ -128,6 +128,7 @@ extern int sctp_register_pf(struct sctp_pf *, sa_family_t); int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb); int sctp_inet_listen(struct socket *sock, int backlog); void sctp_write_space(struct sock *sk); +void sctp_data_ready(struct sock *sk, int len); unsigned int sctp_poll(struct file *file, struct socket *sock, poll_table *wait); void sctp_sock_rfree(struct sk_buff *skb); -- cgit v1.1 From c0786693404cffd80ca3cb6e75ee7b35186b2825 Mon Sep 17 00:00:00 2001 From: Vlad Yasevich Date: Wed, 28 Apr 2010 08:47:22 +0000 Subject: sctp: Fix oops when sending queued ASCONF chunks When we finish processing ASCONF_ACK chunk, we try to send the next queued ASCONF. This action runs the sctp state machine recursively and it's not prepared to do so. kernel BUG at kernel/timer.c:790! invalid opcode: 0000 [#1] SMP last sysfs file: /sys/module/ipv6/initstate Modules linked in: sha256_generic sctp libcrc32c ipv6 dm_multipath uinput 8139too i2c_piix4 8139cp mii i2c_core pcspkr virtio_net joydev floppy virtio_blk virtio_pci [last unloaded: scsi_wait_scan] Pid: 0, comm: swapper Not tainted 2.6.34-rc4 #15 /Bochs EIP: 0060:[] EFLAGS: 00010286 CPU: 0 EIP is at add_timer+0xd/0x1b EAX: cecbab14 EBX: 000000f0 ECX: c0957b1c EDX: 03595cf4 ESI: cecba800 EDI: cf276f00 EBP: c0957aa0 ESP: c0957aa0 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 Process swapper (pid: 0, ti=c0956000 task=c0988ba0 task.ti=c0956000) Stack: c0957ae0 d1851214 c0ab62e4 c0ab5f26 0500ffff 00000004 00000005 00000004 <0> 00000000 d18694fd 00000004 1666b892 cecba800 cecba800 c0957b14 00000004 <0> c0957b94 d1851b11 ceda8b00 cecba800 cf276f00 00000001 c0957b14 000000d0 Call Trace: [] ? sctp_side_effects+0x607/0xdfc [sctp] [] ? sctp_do_sm+0x108/0x159 [sctp] [] ? sctp_pname+0x0/0x1d [sctp] [] ? sctp_primitive_ASCONF+0x36/0x3b [sctp] [] ? sctp_process_asconf_ack+0x2a4/0x2d3 [sctp] [] ? sctp_sf_do_asconf_ack+0x1dd/0x2b4 [sctp] [] ? sctp_do_sm+0xb8/0x159 [sctp] [] ? sctp_cname+0x0/0x52 [sctp] [] ? sctp_assoc_bh_rcv+0xac/0xe1 [sctp] [] ? sctp_inq_push+0x2d/0x30 [sctp] [] ? sctp_rcv+0x797/0x82e [sctp] Tested-by: Wei Yongjun Signed-off-by: Yuansong Qiao Signed-off-by: Shuaijun Zhang Signed-off-by: Vlad Yasevich Signed-off-by: David S. Miller --- include/net/sctp/command.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/net/sctp') diff --git a/include/net/sctp/command.h b/include/net/sctp/command.h index 8be5135..2c55a7e 100644 --- a/include/net/sctp/command.h +++ b/include/net/sctp/command.h @@ -107,6 +107,7 @@ typedef enum { SCTP_CMD_T1_RETRAN, /* Mark for retransmission after T1 timeout */ SCTP_CMD_UPDATE_INITTAG, /* Update peer inittag */ SCTP_CMD_SEND_MSG, /* Send the whole use message */ + SCTP_CMD_SEND_NEXT_ASCONF, /* Send the next ASCONF after ACK */ SCTP_CMD_LAST } sctp_verb_t; -- cgit v1.1 From 5fa782c2f5ef6c2e4f04d3e228412c9b4a4c8809 Mon Sep 17 00:00:00 2001 From: Neil Horman Date: Wed, 28 Apr 2010 10:30:59 +0000 Subject: sctp: Fix skb_over_panic resulting from multiple invalid parameter errors (CVE-2010-1173) (v4) Ok, version 4 Change Notes: 1) Minor cleanups, from Vlads notes Summary: Hey- Recently, it was reported to me that the kernel could oops in the following way: <5> kernel BUG at net/core/skbuff.c:91! <5> invalid operand: 0000 [#1] <5> Modules linked in: sctp netconsole nls_utf8 autofs4 sunrpc iptable_filter ip_tables cpufreq_powersave parport_pc lp parport vmblock(U) vsock(U) vmci(U) vmxnet(U) vmmemctl(U) vmhgfs(U) acpiphp dm_mirror dm_mod button battery ac md5 ipv6 uhci_hcd ehci_hcd snd_ens1371 snd_rawmidi snd_seq_device snd_pcm_oss snd_mixer_oss snd_pcm snd_timer snd_page_alloc snd_ac97_codec snd soundcore pcnet32 mii floppy ext3 jbd ata_piix libata mptscsih mptsas mptspi mptscsi mptbase sd_mod scsi_mod <5> CPU: 0 <5> EIP: 0060:[] Not tainted VLI <5> EFLAGS: 00010216 (2.6.9-89.0.25.EL) <5> EIP is at skb_over_panic+0x1f/0x2d <5> eax: 0000002c ebx: c033f461 ecx: c0357d96 edx: c040fd44 <5> esi: c033f461 edi: df653280 ebp: 00000000 esp: c040fd40 <5> ds: 007b es: 007b ss: 0068 <5> Process swapper (pid: 0, threadinfo=c040f000 task=c0370be0) <5> Stack: c0357d96 e0c29478 00000084 00000004 c033f461 df653280 d7883180 e0c2947d <5> 00000000 00000080 df653490 00000004 de4f1ac0 de4f1ac0 00000004 df653490 <5> 00000001 e0c2877a 08000800 de4f1ac0 df653490 00000000 e0c29d2e 00000004 <5> Call Trace: <5> [] sctp_addto_chunk+0xb0/0x128 [sctp] <5> [] sctp_addto_chunk+0xb5/0x128 [sctp] <5> [] sctp_init_cause+0x3f/0x47 [sctp] <5> [] sctp_process_unk_param+0xac/0xb8 [sctp] <5> [] sctp_verify_init+0xcc/0x134 [sctp] <5> [] sctp_sf_do_5_1B_init+0x83/0x28e [sctp] <5> [] sctp_do_sm+0x41/0x77 [sctp] <5> [] cache_grow+0x140/0x233 <5> [] sctp_endpoint_bh_rcv+0xc5/0x108 [sctp] <5> [] sctp_inq_push+0xe/0x10 [sctp] <5> [] sctp_rcv+0x454/0x509 [sctp] <5> [] ipt_hook+0x17/0x1c [iptable_filter] <5> [] nf_iterate+0x40/0x81 <5> [] ip_local_deliver_finish+0x0/0x151 <5> [] ip_local_deliver_finish+0xc6/0x151 <5> [] nf_hook_slow+0x83/0xb5 <5> [] ip_local_deliver+0x1a2/0x1a9 <5> [] ip_local_deliver_finish+0x0/0x151 <5> [] ip_rcv+0x334/0x3b4 <5> [] netif_receive_skb+0x320/0x35b <5> [] init_stall_timer+0x67/0x6a [uhci_hcd] <5> [] process_backlog+0x6c/0xd9 <5> [] net_rx_action+0xfe/0x1f8 <5> [] __do_softirq+0x35/0x79 <5> [] handle_IRQ_event+0x0/0x4f <5> [] do_softirq+0x46/0x4d Its an skb_over_panic BUG halt that results from processing an init chunk in which too many of its variable length parameters are in some way malformed. The problem is in sctp_process_unk_param: if (NULL == *errp) *errp = sctp_make_op_error_space(asoc, chunk, ntohs(chunk->chunk_hdr->length)); if (*errp) { sctp_init_cause(*errp, SCTP_ERROR_UNKNOWN_PARAM, WORD_ROUND(ntohs(param.p->length))); sctp_addto_chunk(*errp, WORD_ROUND(ntohs(param.p->length)), param.v); When we allocate an error chunk, we assume that the worst case scenario requires that we have chunk_hdr->length data allocated, which would be correct nominally, given that we call sctp_addto_chunk for the violating parameter. Unfortunately, we also, in sctp_init_cause insert a sctp_errhdr_t structure into the error chunk, so the worst case situation in which all parameters are in violation requires chunk_hdr->length+(sizeof(sctp_errhdr_t)*param_count) bytes of data. The result of this error is that a deliberately malformed packet sent to a listening host can cause a remote DOS, described in CVE-2010-1173: http://cve.mitre.org/cgi-bin/cvename.cgi?name=2010-1173 I've tested the below fix and confirmed that it fixes the issue. We move to a strategy whereby we allocate a fixed size error chunk and ignore errors we don't have space to report. Tested by me successfully Signed-off-by: Neil Horman Acked-by: Vlad Yasevich Signed-off-by: David S. Miller --- include/net/sctp/structs.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/net/sctp') diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index ff30177..597f8e2 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -778,6 +778,7 @@ int sctp_user_addto_chunk(struct sctp_chunk *chunk, int off, int len, struct iovec *data); void sctp_chunk_free(struct sctp_chunk *); void *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data); +void *sctp_addto_chunk_fixed(struct sctp_chunk *, int len, const void *data); struct sctp_chunk *sctp_chunkify(struct sk_buff *, const struct sctp_association *, struct sock *); -- cgit v1.1