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Jack Pham 1f4642b72b usb: typec: ucsi: Retrieve all the PDOs instead of just the first 4
commit 4dbc6a4ef0 ("usb: typec: ucsi: save power data objects
in PD mode") introduced retrieval of the PDOs when connected to a
PD-capable source. But only the first 4 PDOs are received since
that is the maximum number that can be fetched at a time given the
MESSAGE_IN length limitation (16 bytes). However, as per the PD spec
a connected source may advertise up to a maximum of 7 PDOs.

If such a source is connected it's possible the PPM could have
negotiated a power contract with one of the PDOs at index greater
than 4, and would be reflected in the request data object's (RDO)
object position field. This would result in an out-of-bounds access
when the rdo_index() is used to index into the src_pdos array in
ucsi_psy_get_voltage_now().

With the help of the UBSAN -fsanitize=array-bounds checker enabled
this exact issue is revealed when connecting to a PD source adapter
that advertise 5 PDOs and the PPM enters a contract having selected
the 5th one.

[  151.545106][   T70] Unexpected kernel BRK exception at EL1
[  151.545112][   T70] Internal error: BRK handler: f2005512 [#1] PREEMPT SMP
...
[  151.545499][   T70] pc : ucsi_psy_get_prop+0x208/0x20c
[  151.545507][   T70] lr : power_supply_show_property+0xc0/0x328
...
[  151.545542][   T70] Call trace:
[  151.545544][   T70]  ucsi_psy_get_prop+0x208/0x20c
[  151.545546][   T70]  power_supply_uevent+0x1a4/0x2f0
[  151.545550][   T70]  dev_uevent+0x200/0x384
[  151.545555][   T70]  kobject_uevent_env+0x1d4/0x7e8
[  151.545557][   T70]  power_supply_changed_work+0x174/0x31c
[  151.545562][   T70]  process_one_work+0x244/0x6f0
[  151.545564][   T70]  worker_thread+0x3e0/0xa64

We can resolve this by instead retrieving and storing up to the
maximum of 7 PDOs in the con->src_pdos array. This would involve
two calls to the GET_PDOS command.

Fixes: 992a60ed0d ("usb: typec: ucsi: register with power_supply class")
Fixes: 4dbc6a4ef0 ("usb: typec: ucsi: save power data objects in PD mode")
Cc: stable@vger.kernel.org
Reported-and-tested-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Jack Pham <jackp@codeaurora.org>
Link: https://lore.kernel.org/r/20210503074611.30973-1-jackp@codeaurora.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-10 15:51:57 +02:00
arch Handle power-gating of AMD IOMMU perf counters properly when they are used. 2021-05-09 13:00:26 -07:00
block block-5.13-2021-05-09 2021-05-09 13:25:14 -07:00
certs Kbuild updates for v5.13 (2nd) 2021-05-08 10:00:11 -07:00
crypto for-5.13/drivers-2021-04-27 2021-04-28 14:39:37 -07:00
Documentation docs: usb: function: Modify path name 2021-05-10 15:06:38 +02:00
drivers usb: typec: ucsi: Retrieve all the PDOs instead of just the first 4 2021-05-10 15:51:57 +02:00
fs 3 small SMB3 chmultichannel related changesets (also for stable) 2021-05-09 13:19:29 -07:00
include block-5.13-2021-05-09 2021-05-09 13:25:14 -07:00
init Merge branch 'akpm' (patches from Andrew) 2021-05-07 00:34:51 -07:00
ipc ipc/sem.c: spelling fix 2021-05-07 00:26:34 -07:00
kernel A set of scheduler updates: 2021-05-09 13:14:34 -07:00
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virt KVM: Boost vCPU candidate in user mode which is delivering interrupt 2021-04-21 12:20:03 -04:00
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MAINTAINERS Networking fixes for 5.13-rc1, including fixes from bpf, can 2021-05-08 08:31:46 -07:00
Makefile Linux 5.13-rc1 2021-05-09 14:17:44 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.