[PATCH v2] thunderbolt: Do not enumerate more ports from DROM than the controller has
From: Mika Westerberg
Date: Tue Jul 25 2017 - 10:42:07 EST
Some Alpine Ridge LP DROMs (there might be others) erroneusly list more
ports than the controller actually has. Most probably because DROM of
the full Dual/Single port Thunderbolt controller was reused for LP
version. The current DROM parser does not check the upper bound thus it
leads to crash when sw->ports[] is accessed over bounds:
BUG: unable to handle kernel NULL pointer dereference at 00000000000002ec
IP: tb_drom_read+0x383/0x890 [thunderbolt]
PGD 0
P4D 0
Oops: 0000 [#1] SMP
CPU: 3 PID: 12248 Comm: systemd-udevd Not tainted 4.13.0-rc1-next-20170719 #1
Hardware name: LENOVO 20HF000YGE/20HF000YGE, BIOS N1WET32W (1.11 ) 05/23/2017
task: ffff8a293e4bcd80 task.stack: ffffa698027a8000
RIP: 0010:tb_drom_read+0x383/0x890 [thunderbolt]
RSP: 0018:ffffa698027ab990 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8a2940af7800 RCX: 0000000000000000
RDX: ffff8a2940ebb400 RSI: 0000000000000000 RDI: ffffa698027ab9a0
RBP: ffffa698027ab9d0 R08: 0000000000000001 R09: 0000000000000002
R10: ffff8a2940ebb5b0 R11: 0000000000000000 R12: ffff8a293bfa968c
R13: 000000000000002c R14: 0000000000000056 R15: 0000000000000056
FS: 00007f0a945a38c0(0000) GS:ffff8a2961580000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000002ec CR3: 000000043e785000 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
tb_switch_add+0x9d/0x730 [thunderbolt]
? tb_switch_alloc+0x3cd/0x4d0 [thunderbolt]
icm_start+0x5a/0xa0 [thunderbolt]
tb_domain_add+0xc3/0xf0 [thunderbolt]
nhi_probe+0x19e/0x310 [thunderbolt]
local_pci_probe+0x42/0xa0
pci_device_probe+0x18d/0x1a0
driver_probe_device+0x2ff/0x450
__driver_attach+0xa4/0xe0
? driver_probe_device+0x450/0x450
bus_for_each_dev+0x6e/0xb0
driver_attach+0x1e/0x20
bus_add_driver+0x1d0/0x270
? 0xffffffffc0bbb000
driver_register+0x60/0xe0
? 0xffffffffc0bbb000
__pci_register_driver+0x4c/0x50
nhi_init+0x28/0x1000 [thunderbolt]
do_one_initcall+0x50/0x190
? __vunmap+0x81/0xb0
? _cond_resched+0x1a/0x50
? kmem_cache_alloc_trace+0x15f/0x1c0
? do_init_module+0x27/0x1e9
do_init_module+0x5f/0x1e9
load_module+0x24e7/0x2a60
? vfs_read+0x115/0x130
SYSC_finit_module+0xfc/0x120
? SYSC_finit_module+0xfc/0x120
SyS_finit_module+0xe/0x10
do_syscall_64+0x67/0x170
entry_SYSCALL64_slow_path+0x25/0x25
Fix this by making sure we only enumerate DROM port entries the hardware
actually has.
Reported-by: Christian Kellner <ckellner@xxxxxxxxxx>
Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Reviewed-by: Lukas Wunner <lukas@xxxxxxxxx>
---
Changes from v1:
- Fix typo in commit message
- Use dev_info_once() instead and change the message not to include
superfluous port numbers
- Added Reviewed-by Lukas
drivers/thunderbolt/eeprom.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/thunderbolt/eeprom.c b/drivers/thunderbolt/eeprom.c
index 308b6e17c88a..fe2f00ceafc5 100644
--- a/drivers/thunderbolt/eeprom.c
+++ b/drivers/thunderbolt/eeprom.c
@@ -333,6 +333,15 @@ static int tb_drom_parse_entry_port(struct tb_switch *sw,
int res;
enum tb_port_type type;
+ /*
+ * Some DROMs list more ports than the controller actually has
+ * so we skip those but allow the parser to continue.
+ */
+ if (header->index > sw->config.max_port_number) {
+ dev_info_once(&sw->dev, "ignoring unnecessary extra entries in DROM\n");
+ return 0;
+ }
+
port = &sw->ports[header->index];
port->disabled = header->port_disabled;
if (port->disabled)
--
2.13.2