kernel/git/next/linux-next.git/drivers/net/gtp.c, branch stable

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

2026-08-24T18:30:39+00:00

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: 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: 459aa660eb1d8ce6 ("gtp: add initial driver for datapath of GPRS Tunneling Protocol (GTP-U)") Reported-by: AutonomousCodeSecurity@microsoft.com Reported-by: Xiang Mei (Microsoft) Reported-by: Cen Zhang (Microsoft) Signed-off-by: Cen Zhang (Microsoft) Link: https://patch.msgid.link/20260820020735.59474-1-blbllhy@gmail.com Signed-off-by: Jakub Kicinski

gtp: serialize PDP context updates

2026-08-22T20:17:12+00:00

PDP contexts can be deleted through GTP_CMD_DELPDP or while the GTP network device is being unregistered. The latter is serialized by RTNL, but the generic-netlink delete path only holds RCU. Running both paths concurrently can therefore make both paths delete the same PDP context. The issue was found through static analysis and reproduced on a KASAN-enabled kernel by a simple two-thread program racing GTP_CMD_DELPDP against RTM_DELLINK: Oops: general protection fault, probably for non-canonical address KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127] RIP: gtp_genl_del_pdp+0x1c1/0x420 [gtp] RBP: dead000000000122 The second deletion dereferenced the poisoned hlist pprev pointer. Serialize gtp_pdp_add(), gtp_genl_del_pdp(), and gtp_dellink() with a shared mutex. Keep the mutex held until the final use of a PDP context in the NEWPDP path, and keep the RCU read-side section around the complete PDP context use in the DELPDP path. Fixes: 459aa660eb1d ("gtp: add initial driver for datapath of GPRS Tunneling Protocol (GTP-U)") Cc: stable@vger.kernel.org Signed-off-by: Qing Ming Link: https://patch.msgid.link/20260818150000.7670-1-a0yami@mailbox.org Signed-off-by: Jakub Kicinski

gtp: check skb_pull_data() return in gtp1u_send_echo_resp()

2026-07-21T22:02:29+00:00

gtp1u_send_echo_resp() ignores skb_pull_data()'s return value. Its caller gtp1u_udp_encap_recv() only guarantees 16 bytes (udphdr + gtp1_header), but the pull requests 20 (gtp1_header_long + udphdr). For a 16-19 byte echo request the pull fails and returns NULL without advancing skb->data; execution continues, and the following skb_push() plus the IP header pushed by iptunnel_xmit() move skb->data below skb->head, tripping skb_under_panic(). Fix it by dropping the packet when skb_pull_data() fails. skbuff: skb_under_panic: ... kernel BUG at net/core/skbuff.c:214! Call Trace: skb_push (net/core/skbuff.c:2648) iptunnel_xmit (net/ipv4/ip_tunnel_core.c:82) gtp_encap_recv (drivers/net/gtp.c:701 drivers/net/gtp.c:808 drivers/net/gtp.c:920) udp_queue_rcv_one_skb (net/ipv4/udp.c:2388) ... Kernel panic - not syncing: Fatal exception in interrupt Fixes: 9af41cc33471 ("gtp: Implement GTP echo response") Reported-by: AutonomousCodeSecurity@microsoft.com Signed-off-by: Xiang Mei (Microsoft) Link: https://patch.msgid.link/20260710230724.942574-1-xmei5@asu.edu Signed-off-by: Jakub Kicinski

gtp: parse extension headers before reading inner protocol

2026-07-21T09:23:30+00:00

GTPv1-U packets may carry a chain of extension headers before the inner IP packet. The receive path already parses and skips these extension headers, but it currently reads the inner protocol before doing so. As a result, the first extension header byte is interpreted as the inner IP version. Packets with extension headers are then dropped before PDP lookup. Parse the extension header chain before calling gtp_inner_proto(), so the inner protocol is read from the actual inner IP header. Fixes: c75fc0b9e5be ("gtp: identify tunnel via GTP device + GTP version + TEID + family") Signed-off-by: Zhixing Chen Link: https://patch.msgid.link/20260708042244.120898-1-running910@gmail.com Signed-off-by: Paolo Abeni

udp_tunnel: Pass struct sock to setup_udp_tunnel_sock().

2026-05-06T00:47:04+00:00

None of the udp_tunnel users need struct socket in their fast paths; it is only used for tunnel setup / teardown. Even setup_udp_tunnel_sock() does not need struct socket. Let's change setup_udp_tunnel_sock() to take struct sock instead of struct socket. Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260502031401.3557229-3-kuniyu@google.com Signed-off-by: Jakub Kicinski

udp_tunnel: Pass struct sock to udp_tunnel_sock_release().

2026-05-06T00:47:03+00:00

None of the udp_tunnel users need struct socket in their fast paths; it is only used for tunnel setup / teardown. While the UDP tunnel interface accepts struct socket, this encourages users to store the pointer unnecessarily. This leads to extra dereferences when accessing struct sock fields (e.g., sk->sk_user_data instead of sock->sk->sk_user_data). Furthermore, these dereferences necessitate synchronize_rcu() in udp_tunnel_sock_release() to protect the fast paths from sock_orphan() setting sk->sk_socket to NULL. This overhead can be avoided if users store the struct sock pointer directly in their private structures. As a prep, let's change udp_tunnel_sock_release() to take struct sock instead of struct socket. Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260502031401.3557229-2-kuniyu@google.com Signed-off-by: Jakub Kicinski

gtp: disable BH before calling udp_tunnel_xmit_skb()

2026-04-20T18:46:24+00:00

gtp_genl_send_echo_req() runs as a generic netlink doit handler in process context with BH not disabled. It calls udp_tunnel_xmit_skb(), which eventually invokes iptunnel_xmit() — that uses __this_cpu_inc/dec on softnet_data.xmit.recursion to track the tunnel xmit recursion level. Without local_bh_disable(), the task may migrate between dev_xmit_recursion_inc() and dev_xmit_recursion_dec(), breaking the per-CPU counter pairing. The result is stale or negative recursion levels that can later produce false-positive SKB_DROP_REASON_RECURSION_LIMIT drops on either CPU. The other udp_tunnel_xmit_skb() call sites in gtp.c are unaffected: the data path runs under ndo_start_xmit and the echo response handlers run from the UDP encap rx softirq, both with BH already disabled. Fix it by disabling BH around the udp_tunnel_xmit_skb() call, mirroring commit 2cd7e6971fc2 ("sctp: disable BH before calling udp_tunnel_xmit_skb()"). Fixes: 6f1a9140ecda ("net: add xmit recursion limit to tunnel xmit functions") Cc: stable@vger.kernel.org Signed-off-by: David Carlier Link: https://patch.msgid.link/20260417055408.4667-1-devnexen@gmail.com Signed-off-by: Jakub Kicinski

drivers: net: drop ipv6_stub usage and use direct function calls

2026-03-29T18:21:23+00:00

As IPv6 is built-in only, the ipv6_stub infrastructure is no longer necessary. Convert all drivers currently utilizing ipv6_stub to make direct function calls. The fallback functions introduced previously will prevent linkage errors when CONFIG_IPV6 is disabled. Signed-off-by: Fernando Fernandez Mancera Tested-by: Ricardo B. Marlière Reviewed-by: Jason A. Donenfeld Reviewed-by: Antonio Quartulli Reviewed-by: Edward Cree Link: https://patch.msgid.link/20260325120928.15848-7-fmancera@suse.de Signed-off-by: Jakub Kicinski

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

gtp: Fix a typo error for size

2025-11-05T01:00:43+00:00

Fix the spelling error of "size". Signed-off-by: Chu Guangqing Reviewed-by: Jacob Keller Link: https://patch.msgid.link/20251103060504.3524-1-chuguangqing@inspur.com Signed-off-by: Jakub Kicinski