[PATCH 5.18 0520/1095] ax25: fix incorrect dev_tracker usage

From: Greg Kroah-Hartman
Date: Mon Aug 15 2022 - 17:23:50 EST

From: Eric Dumazet <edumazet@xxxxxxxxxx>

[ Upstream commit d7c4c9e075f8cc6d88d277bc24e5d99297f03c06 ]

While investigating a separate rose issue [1], and enabling
CONFIG_NET_DEV_REFCNT_TRACKER=y, Bernard reported an orthogonal ax25 issue [2]

An ax25_dev can be used by one (or many) struct ax25_cb.
We thus need different dev_tracker, one per struct ax25_cb.

After this patch is applied, we are able to focus on rose.

[1] https://lore.kernel.org/netdev/fb7544a1-f42e-9254-18cc-c9b071f4ca70@xxxxxxx/

[2]
[ 205.798723] reference already released.
[ 205.798732] allocated in:
[ 205.798734] ax25_bind+0x1a2/0x230 [ax25]
[ 205.798747] __sys_bind+0xea/0x110
[ 205.798753] __x64_sys_bind+0x18/0x20
[ 205.798758] do_syscall_64+0x5c/0x80
[ 205.798763] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 205.798768] freed in:
[ 205.798770] ax25_release+0x115/0x370 [ax25]
[ 205.798778] __sock_release+0x42/0xb0
[ 205.798782] sock_close+0x15/0x20
[ 205.798785] __fput+0x9f/0x260
[ 205.798789] ____fput+0xe/0x10
[ 205.798792] task_work_run+0x64/0xa0
[ 205.798798] exit_to_user_mode_prepare+0x18b/0x190
[ 205.798804] syscall_exit_to_user_mode+0x26/0x40
[ 205.798808] do_syscall_64+0x69/0x80
[ 205.798812] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 205.798827] ------------[ cut here ]------------
[ 205.798829] WARNING: CPU: 2 PID: 2605 at lib/ref_tracker.c:136 ref_tracker_free.cold+0x60/0x81
[ 205.798837] Modules linked in: rose netrom mkiss ax25 rfcomm cmac algif_hash algif_skcipher af_alg bnep snd_hda_codec_hdmi nls_iso8859_1 i915 rtw88_8821ce rtw88_8821c x86_pkg_temp_thermal rtw88_pci intel_powerclamp rtw88_core snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio coretemp snd_hda_intel kvm_intel snd_intel_dspcfg mac80211 snd_hda_codec kvm i2c_algo_bit drm_buddy drm_dp_helper btusb drm_kms_helper snd_hwdep btrtl snd_hda_core btbcm joydev crct10dif_pclmul btintel crc32_pclmul ghash_clmulni_intel mei_hdcp btmtk intel_rapl_msr aesni_intel bluetooth input_leds snd_pcm crypto_simd syscopyarea processor_thermal_device_pci_legacy sysfillrect cryptd intel_soc_dts_iosf snd_seq sysimgblt ecdh_generic fb_sys_fops rapl libarc4 processor_thermal_device intel_cstate processor_thermal_rfim cec snd_timer ecc snd_seq_device cfg80211 processor_thermal_mbox mei_me processor_thermal_rapl mei rc_core at24 snd intel_pch_thermal intel_rapl_common ttm soundcore int340x_thermal_zone video
[ 205.798948] mac_hid acpi_pad sch_fq_codel ipmi_devintf ipmi_msghandler drm msr parport_pc ppdev lp parport ramoops pstore_blk reed_solomon pstore_zone efi_pstore ip_tables x_tables autofs4 hid_generic usbhid hid i2c_i801 i2c_smbus r8169 xhci_pci ahci libahci realtek lpc_ich xhci_pci_renesas [last unloaded: ax25]
[ 205.798992] CPU: 2 PID: 2605 Comm: ax25ipd Not tainted 5.18.11-F6BVP #3
[ 205.798996] Hardware name: To be filled by O.E.M. To be filled by O.E.M./CK3, BIOS 5.011 09/16/2020
[ 205.798999] RIP: 0010:ref_tracker_free.cold+0x60/0x81
[ 205.799005] Code: e8 d2 01 9b ff 83 7b 18 00 74 14 48 c7 c7 2f d7 ff 98 e8 10 6e fc ff 8b 7b 18 e8 b8 01 9b ff 4c 89 ee 4c 89 e7 e8 5d fd 07 00 <0f> 0b b8 ea ff ff ff e9 30 05 9b ff 41 0f b6 f7 48 c7 c7 a0 fa 4e
[ 205.799008] RSP: 0018:ffffaf5281073958 EFLAGS: 00010286
[ 205.799011] RAX: 0000000080000000 RBX: ffff9a0bd687ebe0 RCX: 0000000000000000
[ 205.799014] RDX: 0000000000000001 RSI: 0000000000000282 RDI: 00000000ffffffff
[ 205.799016] RBP: ffffaf5281073a10 R08: 0000000000000003 R09: fffffffffffd5618
[ 205.799019] R10: 0000000000ffff10 R11: 000000000000000f R12: ffff9a0bc53384d0
[ 205.799022] R13: 0000000000000282 R14: 00000000ae000001 R15: 0000000000000001
[ 205.799024] FS: 0000000000000000(0000) GS:ffff9a0d0f300000(0000) knlGS:0000000000000000
[ 205.799028] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 205.799031] CR2: 00007ff6b8311554 CR3: 000000001ac10004 CR4: 00000000001706e0
[ 205.799033] Call Trace:
[ 205.799035] <TASK>
[ 205.799038] ? ax25_dev_device_down+0xd9/0x1b0 [ax25]
[ 205.799047] ? ax25_device_event+0x9f/0x270 [ax25]
[ 205.799055] ? raw_notifier_call_chain+0x49/0x60
[ 205.799060] ? call_netdevice_notifiers_info+0x52/0xa0
[ 205.799065] ? dev_close_many+0xc8/0x120
[ 205.799070] ? unregister_netdevice_many+0x13d/0x890
[ 205.799073] ? unregister_netdevice_queue+0x90/0xe0
[ 205.799076] ? unregister_netdev+0x1d/0x30
[ 205.799080] ? mkiss_close+0x7c/0xc0 [mkiss]
[ 205.799084] ? tty_ldisc_close+0x2e/0x40
[ 205.799089] ? tty_ldisc_hangup+0x137/0x210
[ 205.799092] ? __tty_hangup.part.0+0x208/0x350
[ 205.799098] ? tty_vhangup+0x15/0x20
[ 205.799103] ? pty_close+0x127/0x160
[ 205.799108] ? tty_release+0x139/0x5e0
[ 205.799112] ? __fput+0x9f/0x260
[ 205.799118] ax25_dev_device_down+0xd9/0x1b0 [ax25]
[ 205.799126] ax25_device_event+0x9f/0x270 [ax25]
[ 205.799135] raw_notifier_call_chain+0x49/0x60
[ 205.799140] call_netdevice_notifiers_info+0x52/0xa0
[ 205.799146] dev_close_many+0xc8/0x120
[ 205.799152] unregister_netdevice_many+0x13d/0x890
[ 205.799157] unregister_netdevice_queue+0x90/0xe0
[ 205.799161] unregister_netdev+0x1d/0x30
[ 205.799165] mkiss_close+0x7c/0xc0 [mkiss]
[ 205.799170] tty_ldisc_close+0x2e/0x40
[ 205.799173] tty_ldisc_hangup+0x137/0x210
[ 205.799178] __tty_hangup.part.0+0x208/0x350
[ 205.799184] tty_vhangup+0x15/0x20
[ 205.799188] pty_close+0x127/0x160
[ 205.799193] tty_release+0x139/0x5e0
[ 205.799199] __fput+0x9f/0x260
[ 205.799203] ____fput+0xe/0x10
[ 205.799208] task_work_run+0x64/0xa0
[ 205.799213] do_exit+0x33b/0xab0
[ 205.799217] ? __handle_mm_fault+0xc4f/0x15f0
[ 205.799224] do_group_exit+0x35/0xa0
[ 205.799228] __x64_sys_exit_group+0x18/0x20
[ 205.799232] do_syscall_64+0x5c/0x80
[ 205.799238] ? handle_mm_fault+0xba/0x290
[ 205.799242] ? debug_smp_processor_id+0x17/0x20
[ 205.799246] ? fpregs_assert_state_consistent+0x26/0x50
[ 205.799251] ? exit_to_user_mode_prepare+0x49/0x190
[ 205.799256] ? irqentry_exit_to_user_mode+0x9/0x20
[ 205.799260] ? irqentry_exit+0x33/0x40
[ 205.799263] ? exc_page_fault+0x87/0x170
[ 205.799268] ? asm_exc_page_fault+0x8/0x30
[ 205.799273] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 205.799277] RIP: 0033:0x7ff6b80eaca1
[ 205.799281] Code: Unable to access opcode bytes at RIP 0x7ff6b80eac77.
[ 205.799283] RSP: 002b:00007fff6dfd4738 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
[ 205.799287] RAX: ffffffffffffffda RBX: 00007ff6b8215a00 RCX: 00007ff6b80eaca1
[ 205.799290] RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000001
[ 205.799293] RBP: 0000000000000001 R08: ffffffffffffff80 R09: 0000000000000028
[ 205.799295] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff6b8215a00
[ 205.799298] R13: 0000000000000000 R14: 00007ff6b821aee8 R15: 00007ff6b821af00
[ 205.799304] </TASK>

Fixes: feef318c855a ("ax25: fix UAF bugs of net_device caused by rebinding operation")
Reported-by: Bernard F6BVP <f6bvp@xxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Duoming Zhou <duoming@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220728051821.3160118-1-eric.dumazet@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
include/net/ax25.h | 1 +
net/ax25/af_ax25.c | 4 ++--
2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/net/ax25.h b/include/net/ax25.h
index a427a05672e2..f8cf3629a419 100644
--- a/include/net/ax25.h
+++ b/include/net/ax25.h
@@ -236,6 +236,7 @@ typedef struct ax25_cb {
ax25_address source_addr, dest_addr;
ax25_digi *digipeat;
ax25_dev *ax25_dev;
+ netdevice_tracker dev_tracker;
unsigned char iamdigi;
unsigned char state, modulus, pidincl;
unsigned short vs, vr, va;
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index 4c7030ed8d33..5b5363c99ed5 100644
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -1065,7 +1065,7 @@ static int ax25_release(struct socket *sock)
del_timer_sync(&ax25->t3timer);
del_timer_sync(&ax25->idletimer);
}
- dev_put_track(ax25_dev->dev, &ax25_dev->dev_tracker);
+ dev_put_track(ax25_dev->dev, &ax25->dev_tracker);
ax25_dev_put(ax25_dev);
}

@@ -1146,7 +1146,7 @@ static int ax25_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)

if (ax25_dev) {
ax25_fillin_cb(ax25, ax25_dev);
- dev_hold_track(ax25_dev->dev, &ax25_dev->dev_tracker, GFP_ATOMIC);
+ dev_hold_track(ax25_dev->dev, &ax25->dev_tracker, GFP_ATOMIC);
}

done:
--
2.35.1