kernel: add patch against CVE-2020-14386

fixes #12483

Signed-off-by: Arne Fitzenreiter <arne_f@ipfire.org>

diff --git a/lfs/linux b/lfs/linux
index 24825728695f2d1000561439bdd3487e44db9426..0f118455a271602b2141bdf442d5f5f6096eb753 100644 (file)
--- a/lfs/linux
+++ b/lfs/linux
@@ -144,6 +144,9 @@ $(TARGET) : $(patsubst %,$(DIR_DL)/%,$(objects))
        cd $(DIR_APP) && patch -Np1 < $(DIR_SRC)/src/patches/linux/linux-random_try_to_actively_add_entropy.patch
        cd $(DIR_APP) && patch -Np1 < $(DIR_SRC)/src/patches/linux/linux-4.14.x-add_timer_setup_on_stack.patch
 
+       # Patch CVE-2020-14386
+       cd $(DIR_APP) && patch -Np1 < $(DIR_SRC)/src/patches/linux/linux-cve-2020-14386_net_packet_fix_overflow_in_tpacket_rcv.patch
+
 ifeq "$(KCFG)" "-kirkwood"
        cd $(DIR_APP) && patch -Np1 < $(DIR_SRC)/src/patches/linux/linux-4.14.40-kirkwood-dtb.patch
 endif

diff --git a/src/patches/linux/linux-cve-2020-14386_net_packet_fix_overflow_in_tpacket_rcv.patch b/src/patches/linux/linux-cve-2020-14386_net_packet_fix_overflow_in_tpacket_rcv.patch
new file mode 100644 (file)
index 0000000..439dca7
--- /dev/null
+++ b/src/patches/linux/linux-cve-2020-14386_net_packet_fix_overflow_in_tpacket_rcv.patch
@@ -0,0 +1,54 @@
+From acf69c946233259ab4d64f8869d4037a198c7f06 Mon Sep 17 00:00:00 2001
+From: Or Cohen <orcohen@paloaltonetworks.com>
+Date: Thu, 3 Sep 2020 21:05:28 -0700
+Subject: net/packet: fix overflow in tpacket_rcv
+
+Using tp_reserve to calculate netoff can overflow as
+tp_reserve is unsigned int and netoff is unsigned short.
+
+This may lead to macoff receving a smaller value then
+sizeof(struct virtio_net_hdr), and if po->has_vnet_hdr
+is set, an out-of-bounds write will occur when
+calling virtio_net_hdr_from_skb.
+
+The bug is fixed by converting netoff to unsigned int
+and checking if it exceeds USHRT_MAX.
+
+This addresses CVE-2020-14386
+
+Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt")
+Signed-off-by: Or Cohen <orcohen@paloaltonetworks.com>
+Signed-off-by: Eric Dumazet <edumazet@google.com>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+---
+ net/packet/af_packet.c | 7 ++++++-
+ 1 file changed, 6 insertions(+), 1 deletion(-)
+
+diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
+index da8254e680f94..2b33e977a9059 100644
+--- a/net/packet/af_packet.c
++++ b/net/packet/af_packet.c
+@@ -2170,7 +2170,8 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
+       int skb_len = skb->len;
+       unsigned int snaplen, res;
+       unsigned long status = TP_STATUS_USER;
+-      unsigned short macoff, netoff, hdrlen;
++      unsigned short macoff, hdrlen;
++      unsigned int netoff;
+       struct sk_buff *copy_skb = NULL;
+       struct timespec64 ts;
+       __u32 ts_status;
+@@ -2239,6 +2240,10 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
+               }
+               macoff = netoff - maclen;
+       }
++      if (netoff > USHRT_MAX) {
++              atomic_inc(&po->tp_drops);
++              goto drop_n_restore;
++      }
+       if (po->tp_version <= TPACKET_V2) {
+               if (macoff + snaplen > po->rx_ring.frame_size) {
+                       if (po->copy_thresh &&
+-- 
+cgit 1.2.3-1.el7
+