gtp: add synchronize_net() in gtp_newlink() error path to prevent use-after-free

Browse source

gtp_newlink()'s error path frees tid_hash and addr_hash without
waiting for an RCU grace period after clearing sk_user_data. A
concurrent gtp_encap_recv() in softirq may still hold the gtp_dev
pointer obtained via rcu_dereference_sk_user_data() and access the
freed memory.

  BUG: KASAN: slab-use-after-free in gtp0_pdp_find+0x1f6/0x200 (gtp.c:152)
  Call Trace:
   <IRQ>
   gtp0_pdp_find+0x1f6/0x200
   gtp_encap_recv+0x527/0x24b0
   udp_queue_rcv_one_skb+0x75f/0xc10

Add synchronize_net() before the kfree calls in out_hashtable, which
covers all error paths from both gtp_encap_enable() and
gtp_create_sockets().

Fixes: 459aa660eb ("gtp: add initial driver for datapath of GPRS Tunneling Protocol (GTP-U)")
Reported-by: AutonomousCodeSecurity@microsoft.com
Reported-by: Xiang Mei (Microsoft) <xmei5@asu.edu>
Reported-by: Cen Zhang (Microsoft) <blbllhy@gmail.com>
Signed-off-by: Cen Zhang (Microsoft) <blbllhy@gmail.com>
Link: https://patch.msgid.link/20260820020735.59474-1-blbllhy@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

...

This commit is contained in:

Cen Zhang (Microsoft) 2026-08-19 22:07:35 -04:00 • committed by Jakub Kicinski

parent 3e995a30b9

commit d989e22ae9

1 changed files with 2 additions and 0 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

2

drivers/net/gtp.c

View file