usb: typec: ucsi: Fix connector status writing past buffer size

Similar to commit 65c4c9447bfc ("usb: typec: ucsi: Fix a missing bits to
bytes conversion in ucsi_init()"), there was a missing conversion from
bits to bytes. Here the outcome is worse though: since the value is
lower than UCSI_MAX_DATA_LENGTH, instead of bailing out with an error,
it writes past the buffer size.

The error is then seen in other places like below:

	Oops: general protection fault, probably for non-canonical address 0x891e812cd0ed968: 0000 [#1] PREEMPT SMP NOPTI
	CPU: 3 UID: 110 PID: 906 Comm: prometheus-node Not tainted 6.13.0-rc1-xe #1
	Hardware name: Intel Corporation Lunar Lake Client Platform/LNL-M LP5 RVP1, BIOS LNLMFWI1.R00.3222.D84.2410171025 10/17/2024
	RIP: 0010:power_supply_get_property+0x3e/0xe0
	Code: 85 c0 7e 4f 4c 8b 07 89 f3 49 89 d4 49 8b 48 20 48 85 c9 74 72 49 8b 70 18 31 d2 31 c0 eb 0b 83 c2 01 48 63 c2 48 39 c8 73 5d <3b> 1c 86 75 f0 49 8b 40 28 4c 89 e2 89 de ff d0 0f 1f 00 5b 41 5c
	RSP: 0018:ffffc900017dfa50 EFLAGS: 00010246
	RAX: 0000000000000000 RBX: 0000000000000011 RCX: c963b02c06092008
	RDX: 0000000000000000 RSI: 0891e812cd0ed968 RDI: ffff888121dd6800
	RBP: ffffc900017dfa68 R08: ffff88810a4024b8 R09: 0000000000000000
	R10: 0000000000000000 R11: 0000000000000000 R12: ffffc900017dfa78
	R13: ffff888121dd6800 R14: ffff888138ad2c00 R15: ffff88810c57c528
	FS:  00007713a2ffd6c0(0000) GS:ffff88846f380000(0000) knlGS:0000000000000000
	CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
	CR2: 000000c0004b1000 CR3: 0000000121ce8003 CR4: 0000000000f72ef0
	DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
	DR3: 0000000000000000 DR6: 00000000ffff07f0 DR7: 0000000000000400
	PKRU: 55555554
	Call Trace:
	 <TASK>
	 ? show_regs+0x6c/0x80
	 ? die_addr+0x37/0xa0
	 ? exc_general_protection+0x1c1/0x440
	 ? asm_exc_general_protection+0x27/0x30
	 ? power_supply_get_property+0x3e/0xe0
	 power_supply_hwmon_read+0x50/0xe0
	 hwmon_attr_show+0x46/0x170
	 dev_attr_show+0x1a/0x70
	 sysfs_kf_seq_show+0xaa/0x120
	 kernfs_seq_show+0x41/0x60

Just use the buffer size as argument to fix it.

Fixes: 226ff2e681d0 ("usb: typec: ucsi: Convert connector specific commands to bitmaps")
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reported-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
Closes: https://lore.kernel.org/all/SJ1PR11MB6129CCD82CD78D8EE6E27EF4B9362@SJ1PR11MB6129.namprd11.prod.outlook.com/
Suggested-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Tested-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
Link: https://lore.kernel.org/r/20241203200010.2821132-1-lucas.demarchi@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index 7a65a7672e183ba664bc9671eb348cdf360cc4ac..fcf499cc9458c0d12015a7e36e5f1ac448c3a431 100644 (file)
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -653,7 +653,8 @@ static void ucsi_unregister_altmodes(struct ucsi_connector *con, u8 recipient)
 static int ucsi_get_connector_status(struct ucsi_connector *con, bool conn_ack)
 {
        u64 command = UCSI_GET_CONNECTOR_STATUS | UCSI_CONNECTOR_NUMBER(con->num);
-       size_t size = min(UCSI_GET_CONNECTOR_STATUS_SIZE, UCSI_MAX_DATA_LENGTH(con->ucsi));
+       size_t size = min(sizeof(con->status),
+                         UCSI_MAX_DATA_LENGTH(con->ucsi));
        int ret;
 
        ret = ucsi_send_command_common(con->ucsi, command, &con->status, size, conn_ack);