When calculating the INIT/INIT-ACK chunk length, we should not only account the length of parameters, but also the parameters zero padding length, such as AUTH HMACS parameter and CHUNKS parameter. Without the parameters zero padding length we may get following oops. skb_over_panic: text:ce2068d2 len:130 put:6 head:cac3fe00 data:cac3fe00 tail:0xcac3fe82 end:0xcac3fe80 dev:<NULL> ------------[ cut here ]------------ kernel BUG at net/core/skbuff.c:127! invalid opcode: 0000 [#2] SMP last sysfs file: /sys/module/aes_generic/initstate Modules linked in: authenc ...... Pid: 4102, comm: sctp_darn Tainted: G D 2.6.34-rc2 #6 EIP: 0060:[<c0607630>] EFLAGS: 00010282 CPU: 0 EIP is at skb_over_panic+0x37/0x3e EAX: 00000078 EBX: c07c024b ECX: c07c02b9 EDX: cb607b78 ESI: 00000000 EDI: cac3fe7a EBP: 00000002 ESP: cb607b74 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 Process sctp_darn (pid: 4102, ti=cb607000 task=cabdc990 task.ti=cb607000) Stack: c07c02b9 ce2068d2 00000082 00000006 cac3fe00 cac3fe00 cac3fe82 cac3fe80 <0> c07c024b cac3fe7c cac3fe7a c0608dec ca986e80 ce2068d2 00000006 0000007a <0> cb8120ca ca986e80 cb812000 00000003 cb8120c4 ce208a25 cb8120ca cadd9400 Call Trace: [<ce2068d2>] ? sctp_addto_chunk+0x45/0x85 [sctp] [<c0608dec>] ? skb_put+0x2e/0x32 [<ce2068d2>] ? sctp_addto_chunk+0x45/0x85 [sctp] [<ce208a25>] ? sctp_make_init+0x279/0x28c [sctp] [<c0686a92>] ? apic_timer_interrupt+0x2a/0x30 [<ce1fdc0b>] ? sctp_sf_do_prm_asoc+0x2b/0x7b [sctp] [<ce202823>] ? sctp_do_sm+0xa0/0x14a [sctp] [<ce2133b9>] ? sctp_pname+0x0/0x14 [sctp] [<ce211d72>] ? sctp_primitive_ASSOCIATE+0x2b/0x31 [sctp] [<ce20f3cf>] ? sctp_sendmsg+0x7a0/0x9eb [sctp] [<c064eb1e>] ? inet_sendmsg+0x3b/0x43 [<c04244b7>] ? task_tick_fair+0x2d/0xd9 [<c06031e1>] ? sock_sendmsg+0xa7/0xc1 [<c0416afe>] ? smp_apic_timer_interrupt+0x6b/0x75 [<c0425123>] ? dequeue_task_fair+0x34/0x19b [<c0446abb>] ? sched_clock_local+0x17/0x11e [<c052ea87>] ? _copy_from_user+0x2b/0x10c [<c060ab3a>] ? verify_iovec+0x3c/0x6a [<c06035ca>] ? sys_sendmsg+0x186/0x1e2 [<c042176b>] ? __wake_up_common+0x34/0x5b [<c04240c2>] ? __wake_up+0x2c/0x3b [<c057e35c>] ? tty_wakeup+0x43/0x47 [<c04430f2>] ? remove_wait_queue+0x16/0x24 [<c0580c94>] ? n_tty_read+0x5b8/0x65e [<c042be02>] ? default_wake_function+0x0/0x8 [<c0604e0e>] ? sys_socketcall+0x17f/0x1cd [<c040264c>] ? sysenter_do_call+0x12/0x22 Code: 0f 45 de 53 ff b0 98 00 00 00 ff b0 94 ...... EIP: [<c0607630>] skb_over_panic+0x37/0x3e SS:ESP 0068:cb607b74 To reproduce: # modprobe sctp # echo 1 > /proc/sys/net/sctp/addip_enable # echo 1 > /proc/sys/net/sctp/auth_enable # sctp_test -H 3ffe:501:ffff:100:20c:29ff:fe4d:f37e -P 800 -l # sctp_darn -H 3ffe:501:ffff:100:20c:29ff:fe4d:f37e -P 900 -h 192.168.0.21 -p 800 -I -s -t sctp_darn ready to send... 3ffe:501:ffff:100:20c:29ff:fe4d:f37e:900-192.168.0.21:800 Interactive mode> bindx-add=192.168.0.21 3ffe:501:ffff:100:20c:29ff:fe4d:f37e:900-192.168.0.21:800 Interactive mode> bindx-add=192.168.1.21 3ffe:501:ffff:100:20c:29ff:fe4d:f37e:900-192.168.0.21:800 Interactive mode> snd=10 ------------------------------------------------------------------ eth0 has addresses: 3ffe:501:ffff:100:20c:29ff:fe4d:f37e and 192.168.0.21 eth1 has addresses: 192.168.1.21 ------------------------------------------------------------------
Upstream commit: http://git.kernel.org/linus/a8170c35e738d62e9919ce5b109cf4ed66e95bde
Statement: This issue did not affect the version of Linux kernel as shipped with Red Hat Enterprise Linux 4 as it did not support SCTP authentication and extended parameters. It did not affect the version of Linux kernel as shipped with Red Hat Enterprise MRG as it has backported the upstream commit a8170c35 that addressed this. This has been addressed in Red Hat Enterprise Linux 5 and 6 via https://rhn.redhat.com/errata/RHSA-2011-0927.html and https://rhn.redhat.com/errata/RHSA-2011-0498.html.
This was assigned the name CVE-2011-1573: http://permalink.gmane.org/gmane.comp.security.oss.general/4856
This issue has been addressed in following products: Red Hat Enterprise Linux 6 Via RHSA-2011:0498 https://rhn.redhat.com/errata/RHSA-2011-0498.html
This issue has been addressed in following products: Red Hat Enterprise Linux 5 Via RHSA-2011:0927 https://rhn.redhat.com/errata/RHSA-2011-0927.html