Re: [PATCH] usb: typec: ucsi: Fix connector status writing past buffer size

[Todd Brandt <todd.e.brandt@linux.intel.com>]

Hi all, I opened a bugzilla here about this issue, this commit broke
all our lunar lake machines in boot (5 in total):

https://bugzilla.kernel.org/show_bug.cgi?id=219562

I have tested this patch and it appears to have fixed things. I'm about
to test on all machines with a full run of stress testing of S2idle to
be absolutely sure. But you can add me as tested by.

Tested-By: Brandt, Todd E <todd.e.brandt@linux.intel.com>


On Tue, 2024-12-03 at 12:00 -0800, Lucas De Marchi wrote:
> 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>
> ---
>  drivers/usb/typec/ucsi/ucsi.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi.c
> b/drivers/usb/typec/ucsi/ucsi.c
> index c435c0835744a..69caae84879e9 100644
> --- a/drivers/usb/typec/ucsi/ucsi.c
> +++ b/drivers/usb/typec/ucsi/ucsi.c
> @@ -651,7 +651,8 @@ 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);