Wind River Support Network

Description

In the Linux kernel, the following vulnerability has been resolved:  net/sched: teql: fix NULL pointer dereference in iptunnel_xmit on TEQL slave xmit  teql_master_xmit() calls netdev_start_xmit(skb, slave) to transmit through slave devices, but does not update skb->dev to the slave device beforehand.  When a gretap tunnel is a TEQL slave, the transmit path reaches iptunnel_xmit() which saves dev = skb->dev (still pointing to teql0 master) and later calls iptunnel_xmit_stats(dev, pkt_len). This function does:      get_cpu_ptr(dev->tstats)  Since teql_master_setup() does not set dev->pcpu_stat_type to NETDEV_PCPU_STAT_TSTATS, the core network stack never allocates tstats for teql0, so dev->tstats is NULL. get_cpu_ptr(NULL) computes NULL + __per_cpu_offset[cpu], resulting in a page fault.   BUG: unable to handle page fault for address: ffff8880e6659018  #PF: supervisor write access in kernel mode  #PF: error_code(0x0002) - not-present page  PGD 68bc067 P4D 68bc067 PUD 0  Oops: Oops: 0002 [#1] SMP KASAN PTI  RIP: 0010:iptunnel_xmit (./include/net/ip_tunnels.h:664 net/ipv4/ip_tunnel_core.c:89)  Call Trace:   <TASK>   ip_tunnel_xmit (net/ipv4/ip_tunnel.c:847)   __gre_xmit (net/ipv4/ip_gre.c:478)   gre_tap_xmit (net/ipv4/ip_gre.c:779)   teql_master_xmit (net/sched/sch_teql.c:319)   dev_hard_start_xmit (net/core/dev.c:3887)   sch_direct_xmit (net/sched/sch_generic.c:347)   __dev_queue_xmit (net/core/dev.c:4802)   neigh_direct_output (net/core/neighbour.c:1660)   ip_finish_output2 (net/ipv4/ip_output.c:237)   __ip_finish_output.part.0 (net/ipv4/ip_output.c:315)   ip_mc_output (net/ipv4/ip_output.c:369)   ip_send_skb (net/ipv4/ip_output.c:1508)   udp_send_skb (net/ipv4/udp.c:1195)   udp_sendmsg (net/ipv4/udp.c:1485)   inet_sendmsg (net/ipv4/af_inet.c:859)   __sys_sendto (net/socket.c:2206)  Fix this by setting skb->dev = slave before calling netdev_start_xmit(), so that tunnel xmit functions see the correct slave device with properly allocated tstats.