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-rw-r--r--netfilter-ctnetlink-add-range-check-for-l3-l4-protonum.patch63
1 files changed, 63 insertions, 0 deletions
diff --git a/netfilter-ctnetlink-add-range-check-for-l3-l4-protonum.patch b/netfilter-ctnetlink-add-range-check-for-l3-l4-protonum.patch
new file mode 100644
index 000000000..5e3901440
--- /dev/null
+++ b/netfilter-ctnetlink-add-range-check-for-l3-l4-protonum.patch
@@ -0,0 +1,63 @@
+From 1cc5ef91d2ff94d2bf2de3b3585423e8a1051cb6 Mon Sep 17 00:00:00 2001
+From: Will McVicker <willmcvicker@google.com>
+Date: Mon, 24 Aug 2020 19:38:32 +0000
+Subject: netfilter: ctnetlink: add a range check for l3/l4 protonum
+
+The indexes to the nf_nat_l[34]protos arrays come from userspace. So
+check the tuple's family, e.g. l3num, when creating the conntrack in
+order to prevent an OOB memory access during setup. Here is an example
+kernel panic on 4.14.180 when userspace passes in an index greater than
+NFPROTO_NUMPROTO.
+
+Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
+Modules linked in:...
+Process poc (pid: 5614, stack limit = 0x00000000a3933121)
+CPU: 4 PID: 5614 Comm: poc Tainted: G S W O 4.14.180-g051355490483
+Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150 Google Inc. MSM
+task: 000000002a3dfffe task.stack: 00000000a3933121
+pc : __cfi_check_fail+0x1c/0x24
+lr : __cfi_check_fail+0x1c/0x24
+...
+Call trace:
+__cfi_check_fail+0x1c/0x24
+name_to_dev_t+0x0/0x468
+nfnetlink_parse_nat_setup+0x234/0x258
+ctnetlink_parse_nat_setup+0x4c/0x228
+ctnetlink_new_conntrack+0x590/0xc40
+nfnetlink_rcv_msg+0x31c/0x4d4
+netlink_rcv_skb+0x100/0x184
+nfnetlink_rcv+0xf4/0x180
+netlink_unicast+0x360/0x770
+netlink_sendmsg+0x5a0/0x6a4
+___sys_sendmsg+0x314/0x46c
+SyS_sendmsg+0xb4/0x108
+el0_svc_naked+0x34/0x38
+
+This crash is not happening since 5.4+, however, ctnetlink still
+allows for creating entries with unsupported layer 3 protocol number.
+
+Fixes: c1d10adb4a521 ("[NETFILTER]: Add ctnetlink port for nf_conntrack")
+Signed-off-by: Will McVicker <willmcvicker@google.com>
+[pablo@netfilter.org: rebased original patch on top of nf.git]
+Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
+---
+ net/netfilter/nf_conntrack_netlink.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
+index 832eabecfbddc..d65846aa80591 100644
+--- a/net/netfilter/nf_conntrack_netlink.c
++++ b/net/netfilter/nf_conntrack_netlink.c
+@@ -1404,7 +1404,8 @@ ctnetlink_parse_tuple_filter(const struct nlattr * const cda[],
+ if (err < 0)
+ return err;
+
+-
++ if (l3num != NFPROTO_IPV4 && l3num != NFPROTO_IPV6)
++ return -EOPNOTSUPP;
+ tuple->src.l3num = l3num;
+
+ if (flags & CTA_FILTER_FLAG(CTA_IP_DST) ||
+--
+cgit 1.2.3-1.el7
+