Plugging in a USB type C dock causes an Oops due to an array
overrun of ->partner_altmode[].
con->partner_altmode[i] ends up with the value 0x2 in the call and it's
because the array has been accessed out of bounds resulting in random
contents of memory being checked. The patch was generated and tested
against 5.8.0-rc6.
[ 565.452023] BUG: kernel NULL pointer dereference, address: 00000000000002fe
[ 565.452025] #PF: supervisor read access in kernel mode
[ 565.452026] #PF: error_code(0x0000) - not-present page
[ 565.452026] PGD 0 P4D 0
[ 565.452028] Oops: 0000 [#1] PREEMPT SMP NOPTI
[ 565.452030] CPU: 0 PID: 502 Comm: kworker/0:3 Not tainted 5.8.0-rc3+ #1
[ 565.452031] Hardware name: LENOVO 20RD002VUS/20RD002VUS,
BIOS R16ET25W (1.11 ) 04/21/2020
[ 565.452034] Workqueue: events ucsi_handle_connector_change [typec_ucsi]
[ 565.452039] RIP: 0010:typec_altmode_update_active+0x1f/0x100 [typec]
[ 565.452040] Code: 0f 1f 84 00 00 00 00 00 0f 1f 00 0f 1f 44 00 00 55 48
89 e5 41 54 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 45 e8 31 c0
<0f> b6 87 fc 02 00 00 83 e0 01 40 38 f0 0f 84 95 00 00 00 48 8b 47
[ 565.452041] RSP: 0018:ffffb729c066bdb0 EFLAGS: 00010246
[ 565.452042] RAX: 0000000000000000 RBX: ffffa067c3e64a70 RCX: 0000000000000000
[ 565.452043] RDX: ffffb729c066bd20 RSI: 0000000000000000 RDI: 0000000000000002
[ 565.452044] RBP: ffffb729c066bdd0 R08: 00000083a7910a4f R09: 0000000000000000
[ 565.452044] R10: ffffffffa106a220 R11: 0000000000000000 R12: 0000000000000000
[ 565.452045] R13: ffffa067c3e64a98 R14: ffffa067c3e64810 R15: ffffa067c3e64800
[ 565.452046] FS: 0000000000000000(0000) GS:ffffa067d1400000(0000)
knlGS:0000000000000000
[ 565.452047] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 565.452048] CR2: 00000000000002fe CR3: 00000001b060a003 CR4: 00000000003606f0
[ 565.452048] Call Trace:
[ 565.452052] ucsi_altmode_update_active+0x83/0xd0 [typec_ucsi]
[ 565.452054] ucsi_handle_connector_change+0x1dc/0x320 [typec_ucsi]
[ 565.452057] process_one_work+0x1df/0x3d0
[ 565.452059] worker_thread+0x4d/0x3d0
[ 565.452060] ? process_one_work+0x3d0/0x3d0
[ 565.452062] kthread+0x127/0x170
[ 565.452063] ? kthread_park+0x90/0x90
[ 565.452065] ret_from_fork+0x1f/0x30
The failing instruction is;
0x0000000000000380 <+0>: callq 0x385 <typec_altmode_update_active+5>
0x0000000000000385 <+5>: push %rbp
0x0000000000000386 <+6>: mov %rsp,%rbp
0x0000000000000389 <+9>: push %r12
0x000000000000038b <+11>: push %rbx
0x000000000000038c <+12>: sub $0x10,%rsp
0x0000000000000390 <+16>: mov %gs:0x28,%rax
0x0000000000000399 <+25>: mov %rax,-0x18(%rbp)
0x000000000000039d <+29>: xor %eax,%eax
0x000000000000039f <+31>: movzbl 0x2fc(%rdi),%eax <======
0x00000000000003a6 <+38>: and $0x1,%eax
(gdb) list *typec_altmode_update_active+0x1f
0x39f is in typec_altmode_update_active (drivers/usb/typec/class.c:221).
216 */
217 void typec_altmode_update_active(struct typec_altmode *adev, bool active)
218 {
219 char dir[6];
220
221 if (adev->active == active)
222 return;
223
224 if (!is_typec_port(adev->dev.parent) && adev->dev.driver) {
225 if (!active)
(gdb) list *ucsi_altmode_update_active+0x83
0x12a3 is in ucsi_altmode_update_active (drivers/usb/typec/ucsi/ucsi.c:221).
216 }
217
218 if (cur < UCSI_MAX_ALTMODES)
219 altmode = typec_altmode_get_partner(con->port_altmode[cur]);
220
221 for (i = 0; con->partner_altmode[i]; i++)
222 typec_altmode_update_active(con->partner_altmode[i],
223 con->partner_altmode[i] == altmode);
224 }
This oops is for a similar array overrun in ucsi_unregister_altmodes
[ 4372.429633] usb 1-2.1.4: USB disconnect, device number 16
[ 4372.523235] usb 1-2.2: USB disconnect, device number 7
[ 4372.570537] usb 1-2.5: USB disconnect, device number 9
[ 4373.153246] BUG: kernel NULL pointer dereference, address: 00000000000002f2
[ 4373.153267] #PF: supervisor read access in kernel mode
[ 4373.153271] #PF: error_code(0x0000) - not-present page
[ 4373.153275] PGD 0 P4D 0
[ 4373.153284] Oops: 0000 [#2] PREEMPT SMP NOPTI
[ 4373.153292] CPU: 0 PID: 13242 Comm: kworker/0:0 Tainted: G D
5.8.0-rc6+ #1
[ 4373.153296] Hardware name: LENOVO 20RD002VUS/20RD002VUS, BIOS R16ET25W (1.11 )
04/21/2020
[ 4373.153308] Workqueue: events ucsi_handle_connector_change [typec_ucsi]
[ 4373.153320] RIP: 0010:ucsi_unregister_altmodes+0x5f/0xa0 [typec_ucsi]
[ 4373.153326] Code: 54 48 8b 3b 41 83 c4 01 e8 9e f9 0c 00 49 63 c4 48 c7
03 00 00 00 00 49 8d 5c c5 00 48 8b 3b 48 85 ff 74 31 41 80 fe 01 75 d7
<0f> b7 87 f0 02 00 00 66 3d 01 ff 74 0f 66 3d 55 09 75 c4 83 bf f8
[ 4373.153332] RSP: 0018:ffffb2ef036b3dc8 EFLAGS: 00010246
[ 4373.153338] RAX: 000000000000001e RBX: ffff94268b006a60 RCX: 0000000080800067
[ 4373.153342] RDX: 0000000080800068 RSI: 0000000000000001 RDI: 0000000000000002
[ 4373.153347] RBP: ffffb2ef036b3de8 R08: 0000000000000000 R09: ffffffff8dc65400
[ 4373.153351] R10: ffff9426678d7200 R11: 0000000000000001 R12: 000000000000001e
[ 4373.153355] R13: ffff94268b006970 R14: 0000000000000001 R15: ffff94268b006800
[ 4373.153361] FS: 0000000000000000(0000) GS:ffff942691400000(0000)
knlGS:0000000000000000
[ 4373.153366] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4373.153371] CR2: 00000000000002f2 CR3: 00000004445a6005 CR4: 00000000003606f0
[ 4373.153375] Call Trace:
[ 4373.153389] ucsi_unregister_partner.part.0+0x17/0x30 [typec_ucsi]
[ 4373.153400] ucsi_handle_connector_change+0x25c/0x320 [typec_ucsi]
[ 4373.153418] process_one_work+0x1df/0x3d0
[ 4373.153428] worker_thread+0x4a/0x3d0
[ 4373.153436] ? process_one_work+0x3d0/0x3d0
[ 4373.153444] kthread+0x127/0x170
[ 4373.153451] ? kthread_park+0x90/0x90
[ 4373.153461] ret_from_fork+0x1f/0x30
[ 4373.153661] CR2: 00000000000002f2
Signed-off-by: Zwane Mwaikambo <zwane@xxxxxxxxx>
---
diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index d0c63afaf..79061705e 100644
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -218,9 +218,10 @@ void ucsi_altmode_update_active(struct ucsi_connector *con)
if (cur < UCSI_MAX_ALTMODES)
altmode = typec_altmode_get_partner(con->port_altmode[cur]);
- for (i = 0; con->partner_altmode[i]; i++)
- typec_altmode_update_active(con->partner_altmode[i],
- con->partner_altmode[i] == altmode);
+ for (i = 0; i < UCSI_MAX_ALTMODES; i++)
+ if (con->partner_altmode[i])
+ typec_altmode_update_active(con->partner_altmode[i],
+ con->partner_altmode[i] == altmode);
}
static u8 ucsi_altmode_next_mode(struct typec_altmode **alt, u16 svid)
@@ -479,7 +480,10 @@ static void ucsi_unregister_altmodes(struct ucsi_connector *con, u8 recipient)
return;
}
- while (adev[i]) {
+ for (i = 0; i < UCSI_MAX_ALTMODES; i++) {
+ if (!adev[i])
+ break;
+
if (recipient == UCSI_RECIPIENT_SOP &&
(adev[i]->svid == USB_TYPEC_DP_SID ||
(adev[i]->svid == USB_TYPEC_NVIDIA_VLINK_SID &&
@@ -488,7 +492,7 @@ static void ucsi_unregister_altmodes(struct ucsi_connector *con, u8 recipient)
ucsi_displayport_remove_partner((void *)pdev);
}
typec_unregister_altmode(adev[i]);
- adev[i++] = NULL;
+ adev[i] = NULL;
}
}
