kernel: add patch agains CVE-2020-14386

fixes #12483

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

diff --git a/lfs/linux b/lfs/linux
index 8bec9615095881a75a015ea81e9dbcdfff32ca42..cb9942938b2bdce976f901ba0bb87dd6462fdb6a 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 < $(DIR_SRC)/src/patches/linux/linux-4.14_cve-2020-14386_net_packet_fix_overflow_in_tpacket_rcv.patch
+
 ifeq "$(KCFG)" "-multi"
        # Apply Arm-multiarch kernel patches.
        cd $(DIR_APP) && xzcat $(DIR_DL)/arm-multi-patches-$(ARM_PATCHES).patch.xz | patch -Np1

diff --git a/src/patches/linux/linux-4.14_cve-2020-14386_net_packet_fix_overflow_in_tpacket_rcv.patch b/src/patches/linux/linux-4.14_cve-2020-14386_net_packet_fix_overflow_in_tpacket_rcv.patch
new file mode 100644 (file)
index 0000000..a3eb323
--- /dev/null
+++ b/src/patches/linux/linux-4.14_cve-2020-14386_net_packet_fix_overflow_in_tpacket_rcv.patch
@@ -0,0 +1,44 @@
+From: Arne Fitzenreiter <arne.fitzenreiter@ipfire.org>
+
+patch based on acf69c946233259ab4d64f8869d4037a198c7f06
+From: Or Cohen <orcohen@paloaltonetworks.com>
+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
+
+
+diff -Naur linux-4.14.197.org/net/packet/af_packet.c linux-4.14.197/net/packet/af_packet.c
+--- linux-4.14.197.org/net/packet/af_packet.c  2020-09-11 22:27:31.003458577 +0200
++++ linux-4.14.197/net/packet/af_packet.c      2020-09-11 22:38:53.104021712 +0200
+@@ -2201,7 +2201,8 @@
+       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 timespec ts;
+       __u32 ts_status;
+@@ -2264,6 +2265,10 @@
+               }
+               macoff = netoff - maclen;
+       }
++      if (netoff > USHRT_MAX) {
++              po->stats.stats1.tp_drops++;
++              goto drop_n_restore;
++      }
+       if (po->tp_version <= TPACKET_V2) {
+               if (macoff + snaplen > po->rx_ring.frame_size) {
+                       if (po->copy_thresh &&