Subject: CVE-2024-26793: gtp: fix use-after-free and null-ptr-deref in gtp_newlink()

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

gtp: fix use-after-free and null-ptr-deref in gtp_newlink()

The gtp_link_ops operations structure for the subsystem must be
registered after registering the gtp_net_ops pernet operations structure.

Syzkaller hit 'general protection fault in gtp_genl_dump_pdp' bug:

[ 1010.702740] gtp: GTP module unloaded
[ 1010.715877] general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI
[ 1010.715888] KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
[ 1010.715895] CPU: 1 PID: 128616 Comm: a.out Not tainted 6.8.0-rc6-std-def-alt1 #1
[ 1010.715899] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.0-alt1 04/01/2014
[ 1010.715908] RIP: 0010:gtp_newlink+0x4d7/0x9c0 [gtp]
[ 1010.715915] Code: 80 3c 02 00 0f 85 41 04 00 00 48 8b bb d8 05 00 00 e8 ed f6 ff ff 48 89 c2 48 89 c5 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 4f 04 00 00 4c 89 e2 4c 8b 6d 00 48 b8 00 00 00
[ 1010.715920] RSP: 0018:ffff888020fbf180 EFLAGS: 00010203
[ 1010.715929] RAX: dffffc0000000000 RBX: ffff88800399c000 RCX: 0000000000000000
[ 1010.715933] RDX: 0000000000000001 RSI: ffffffff84805280 RDI: 0000000000000282
[ 1010.715938] RBP: 000000000000000d R08: 0000000000000001 R09: 0000000000000000
[ 1010.715942] R10: 0000000000000001 R11: 0000000000000001 R12: ffff88800399cc80
[ 1010.715947] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000400
[ 1010.715953] FS:  00007fd1509ab5c0(0000) GS:ffff88805b300000(0000) knlGS:0000000000000000
[ 1010.715958] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1010.715962] CR2: 0000000000000000 CR3: 000000001c07a000 CR4: 0000000000750ee0
[ 1010.715968] PKRU: 55555554
[ 1010.715972] Call Trace:
[ 1010.715985]  ? __die_body.cold+0x1a/0x1f
[ 1010.715995]  ? die_addr+0x43/0x70
[ 1010.716002]  ? exc_general_protection+0x199/0x2f0
[ 1010.716016]  ? asm_exc_general_protection+0x1e/0x30
[ 1010.716026]  ? gtp_newlink+0x4d7/0x9c0 [gtp]
[ 1010.716034]  ? gtp_net_exit+0x150/0x150 [gtp]
[ 1010.716042]  __rtnl_newlink+0x1063/0x1700
[ 1010.716051]  ? rtnl_setlink+0x3c0/0x3c0
[ 1010.716063]  ? is_bpf_text_address+0xc0/0x1f0
[ 1010.716070]  ? kernel_text_address.part.0+0xbb/0xd0
[ 1010.716076]  ? __kernel_text_address+0x56/0xa0
[ 1010.716084]  ? unwind_get_return_address+0x5a/0xa0
[ 1010.716091]  ? create_prof_cpu_mask+0x30/0x30
[ 1010.716098]  ? arch_stack_walk+0x9e/0xf0
[ 1010.716106]  ? stack_trace_save+0x91/0xd0
[ 1010.716113]  ? stack_trace_consume_entry+0x170/0x170
[ 1010.716121]  ? __lock_acquire+0x15c5/0x5380
[ 1010.716139]  ? mark_held_locks+0x9e/0xe0
[ 1010.716148]  ? kmem_cache_alloc_trace+0x35f/0x3c0
[ 1010.716155]  ? __rtnl_newlink+0x1700/0x1700
[ 1010.716160]  rtnl_newlink+0x69/0xa0
[ 1010.716166]  rtnetlink_rcv_msg+0x43b/0xc50
[ 1010.716172]  ? rtnl_fdb_dump+0x9f0/0x9f0
[ 1010.716179]  ? lock_acquire+0x1fe/0x560
[ 1010.716188]  ? netlink_deliver_tap+0x12f/0xd50
[ 1010.716196]  netlink_rcv_skb+0x14d/0x440
[ 1010.716202]  ? rtnl_fdb_dump+0x9f0/0x9f0
[ 1010.716208]  ? netlink_ack+0xab0/0xab0
[ 1010.716213]  ? netlink_deliver_tap+0x202/0xd50
[ 1010.716220]  ? netlink_deliver_tap+0x218/0xd50
[ 1010.716226]  ? __virt_addr_valid+0x30b/0x590
[ 1010.716233]  netlink_unicast+0x54b/0x800
[ 1010.716240]  ? netlink_attachskb+0x870/0x870
[ 1010.716248]  ? __check_object_size+0x2de/0x3b0
[ 1010.716254]  netlink_sendmsg+0x938/0xe40
[ 1010.716261]  ? netlink_unicast+0x800/0x800
[ 1010.716269]  ? __import_iovec+0x292/0x510
[ 1010.716276]  ? netlink_unicast+0x800/0x800
[ 1010.716284]  __sock_sendmsg+0x159/0x190
[ 1010.716290]  ____sys_sendmsg+0x712/0x880
[ 1010.716297]  ? sock_write_iter+0x3d0/0x3d0
[ 1010.716304]  ? __ia32_sys_recvmmsg+0x270/0x270
[ 1010.716309]  ? lock_acquire+0x1fe/0x560
[ 1010.716315]  ? drain_array_locked+0x90/0x90
[ 1010.716324]  ___sys_sendmsg+0xf8/0x170
[ 1010.716331]  ? sendmsg_copy_msghdr+0x170/0x170
[ 1010.716337]  ? lockdep_init_map_type+0x2c7/0x860
[ 1010.716343]  ? lockdep_hardirqs_on_prepare+0x430/0x430
[ 1010.716350]  ? debug_mutex_init+0x33/0x70
[ 1010.716360]  ? percpu_counter_add_batch+0x8b/0x140
[ 1010.716367]  ? lock_acquire+0x1fe/0x560
[ 1010.716373]  ? find_held_lock+0x2c/0x110
[ 1010.716384]  ? __fd_install+0x1b6/0x6f0
[ 1010.716389]  ? lock_downgrade+0x810/0x810
[ 1010.716396]  ? __fget_light+0x222/0x290
[ 1010.716403]  __sys_sendmsg+0xea/0x1b0
[ 1010.716409]  ? __sys_sendmsg_sock+0x40/0x40
[ 1010.716419]  ? lockdep_hardirqs_on_prepare+0x2b3/0x430
[ 1010.716425]  ? syscall_enter_from_user_mode+0x1d/0x60
[ 1010.716432]  do_syscall_64+0x30/0x40
[ 1010.716438]  entry_SYSCALL_64_after_hwframe+0x62/0xc7
[ 1010.716444] RIP: 0033:0x7fd1508cbd49
[ 1010.716452] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ef 70 0d 00 f7 d8 64 89 01 48
[ 1010.716456] RSP: 002b:00007fff18872348 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
[ 1010.716463] RAX: ffffffffffffffda RBX: 000055f72bf0eac0 RCX: 00007fd1508cbd49
[ 1010.716468] RDX: 0000000000000000 RSI: 0000000020000280 RDI: 0000000000000006
[ 1010.716473] RBP: 00007fff18872360 R08: 00007fff18872360 R09: 00007fff18872360
[ 1010.716478] R10: 00007fff18872360 R11: 0000000000000202 R12: 000055f72bf0e1b0
[ 1010.716482] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 1010.716491] Modules linked in: gtp(+) udp_tunnel ib_core uinput af_packet rfkill qrtr joydev hid_generic usbhid hid kvm_intel iTCO_wdt intel_pmc_bxt iTCO_vendor_support kvm snd_hda_codec_generic ledtrig_audio irqbypass crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel snd_hda_intel nls_utf8 snd_intel_dspcfg nls_cp866 psmouse aesni_intel vfat crypto_simd fat cryptd glue_helper snd_hda_codec pcspkr snd_hda_core i2c_i801 snd_hwdep i2c_smbus xhci_pci snd_pcm lpc_ich xhci_pci_renesas xhci_hcd qemu_fw_cfg tiny_power_button button sch_fq_codel vboxvideo drm_vram_helper drm_ttm_helper ttm vboxsf vboxguest snd_seq_midi snd_seq_midi_event snd_seq snd_rawmidi snd_seq_device snd_timer snd soundcore msr fuse efi_pstore dm_mod ip_tables x_tables autofs4 virtio_gpu virtio_dma_buf drm_kms_helper cec rc_core drm virtio_rng virtio_scsi rng_core virtio_balloon virtio_blk virtio_net virtio_console net_failover failover ahci libahci libata evdev scsi_mod input_leds serio_raw virtio_pci intel_agp
[ 1010.716674]  virtio_ring intel_gtt virtio [last unloaded: gtp]
[ 1010.716693] ---[ end trace 04990a4ce61e174b ]---

The Linux kernel CVE team has assigned CVE-2024-26793 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 4.7 with commit 459aa660eb1d and fixed in 4.19.309 with commit 01129059d514
	Issue introduced in 4.7 with commit 459aa660eb1d and fixed in 5.4.271 with commit ec92aa2cab6f
	Issue introduced in 4.7 with commit 459aa660eb1d and fixed in 5.10.212 with commit e668b92a3a01
	Issue introduced in 4.7 with commit 459aa660eb1d and fixed in 5.15.151 with commit 9376d059a705
	Issue introduced in 4.7 with commit 459aa660eb1d and fixed in 6.1.81 with commit abd32d7f5c02
	Issue introduced in 4.7 with commit 459aa660eb1d and fixed in 6.6.21 with commit 93dd420bc415
	Issue introduced in 4.7 with commit 459aa660eb1d and fixed in 6.7.9 with commit 5366969a19a8
	Issue introduced in 4.7 with commit 459aa660eb1d and fixed in 6.8 with commit 616d82c3cfa2

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-26793
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/net/gtp.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/01129059d5141d62fae692f7a336ae3bc712d3eb
	https://git.kernel.org/stable/c/ec92aa2cab6f0048f10d6aa4f025c5885cb1a1b6
	https://git.kernel.org/stable/c/e668b92a3a01429923fd5ca13e99642aab47de69
	https://git.kernel.org/stable/c/9376d059a705c5dfaac566c2d09891242013ae16
	https://git.kernel.org/stable/c/abd32d7f5c0294c1b2454c5a3b13b18446bac627
	https://git.kernel.org/stable/c/93dd420bc41531c9a31498b9538ca83ba6ec191e
	https://git.kernel.org/stable/c/5366969a19a8a0d2ffb3d27ef6e8905e5e4216f8
	https://git.kernel.org/stable/c/616d82c3cfa2a2146dd7e3ae47bda7e877ee549e