CVE-2014-7841 sctp: NULL ptr deref on malformed packet (rhbz 1163087 1163095)

kernel.spec

@@ -619,6 +619,9 @@ Patch26065: sched-Remove-lockdep-check-in-sched_move_task.patch
 #rhbz 1161805
 Patch26066: ahci-disable-MSI-instead-of-NCQ-on-Samsung-pci-e-SSD.patch
 
+#CVE-2014-7841 rhbz 1163087 1163095
+Patch26067: net-sctp-fix-NULL-pointer-dereference-in-af-from_add.patch
+
 # git clone ssh://git.fedorahosted.org/git/kernel-arm64.git, git diff master...devel
 Patch30000: kernel-arm64.patch
 
@@ -1347,6 +1350,9 @@ ApplyPatch sched-Remove-lockdep-check-in-sched_move_task.patch
 #rhbz 1161805
 ApplyPatch ahci-disable-MSI-instead-of-NCQ-on-Samsung-pci-e-SSD.patch
 
+#CVE-2014-7841 rhbz 1163087 1163095
+ApplyPatch net-sctp-fix-NULL-pointer-dereference-in-af-from_add.patch
+
 %if 0%{?aarch64patches}
 ApplyPatch kernel-arm64.patch
 %ifnarch aarch64 # this is stupid, but i want to notice before secondary koji does.
@@ -2215,6 +2221,9 @@ fi
 #                                    ||----w |
 #                                    ||     ||
 %changelog
+* Wed Nov 12 2014 Josh Boyer <jwboyer@fedoraproject.org>
+- CVE-2014-7841 sctp: NULL ptr deref on malformed packet (rhbz 1163087 1163095)
+
 * Tue Nov 11 2014 Kyle McMartin <kyle@fedoraproject.org> - 3.18.0-0.rc4.git0.2
 - Re-enable kernel-arm64.patch, and fix up merge conflicts with 3.18-rc4
 

net-sctp-fix-NULL-pointer-dereference-in-af-from_add.patch

@@ -0,0 +1,77 @@
+From: Daniel Borkmann <dborkman@redhat.com>
+Date: Mon, 10 Nov 2014 17:54:26 +0100
+Subject: [PATCH] net: sctp: fix NULL pointer dereference in
+ af->from_addr_param on malformed packet
+
+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: [<ffffffffa01e9c62>] 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:[<ffffffffa01e9c62>]  [<ffffffffa01e9c62>] sctp_process_init+0x492/0x990 [sctp]
+[...]
+Call Trace:
+ <IRQ>
+ [<ffffffffa01f2add>] ? sctp_bind_addr_copy+0x5d/0xe0 [sctp]
+ [<ffffffffa01e1fcb>] sctp_sf_do_5_1B_init+0x21b/0x340 [sctp]
+ [<ffffffffa01e3751>] sctp_do_sm+0x71/0x1210 [sctp]
+ [<ffffffffa01e5c09>] ? sctp_endpoint_lookup_assoc+0xc9/0xf0 [sctp]
+ [<ffffffffa01e61f6>] sctp_endpoint_bh_rcv+0x116/0x230 [sctp]
+ [<ffffffffa01ee986>] sctp_inq_push+0x56/0x80 [sctp]
+ [<ffffffffa01fcc42>] sctp_rcv+0x982/0xa10 [sctp]
+ [<ffffffffa01d5123>] ? ipt_local_in_hook+0x23/0x28 [iptable_filter]
+ [<ffffffff8148bdc9>] ? nf_iterate+0x69/0xb0
+ [<ffffffff81496d10>] ? ip_local_deliver_finish+0x0/0x2d0
+ [<ffffffff8148bf86>] ? nf_hook_slow+0x76/0x120
+ [<ffffffff81496d10>] ? 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 <dborkman@redhat.com>
+Cc: Vlad Yasevich <vyasevich@gmail.com>
+Acked-by: Neil Horman <nhorman@tuxdriver.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ net/sctp/sm_make_chunk.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
+index ab734be8cb20..9f32741abb1c 100644
+--- a/net/sctp/sm_make_chunk.c
++++ b/net/sctp/sm_make_chunk.c
+@@ -2609,6 +2609,9 @@ do_addr_param:
+ 		addr_param = param.v + sizeof(sctp_addip_param_t);
+ 
+ 		af = sctp_get_af_specific(param_type2af(param.p->type));
++		if (af == NULL)
++			break;
++
+ 		af->from_addr_param(&addr, addr_param,
+ 				    htons(asoc->peer.port), 0);
+ 
+-- 
+1.9.3
+