On Wed, Nov 9, 2022 at 3:11 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
>
> Hi,
>
> On 11/9/22 22:04, Jorge Lopez wrote:
> > On Wed, Nov 9, 2022 at 2:55 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
> >>
> >> Hi,
> >>
> >> On 11/9/22 21:52, Jorge Lopez wrote:
> >>> On Wed, Nov 9, 2022 at 2:05 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
> >>>>
> >>>> Hi,
> >>>>
> >>>> On 11/9/22 21:00, Jorge Lopez wrote:
> >>>>> Hi Hans,
> >>>>>
> >>>>> On Wed, Nov 9, 2022 at 12:10 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
> >>>>>>
> >>>>>> Hi,
> >>>>>>
> >>>>>> On 11/9/22 18:24, Jorge Lopez wrote:
> >>>>>>> HI Hans,
> >>>>>>>
> >>>>>>> Please see questions and comments below.
> >>>>>>>
> >>>>>>> On Tue, Nov 8, 2022 at 8:51 AM Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
> >>>>>>>>
> >>>>>>>> Hi Jorge,
> >>>>>>>>
> >>>>>>>> Review comments inline.
> >>>>>>>>
> >>>>>>>> On 10/20/22 22:10, Jorge Lopez wrote:
> >>>>>>>>> The purpose for this patch is submit HP BIOSCFG driver to be list of
> >>>>>>>>> HP Linux kernel drivers. The driver include a total of 12 files
> >>>>>>>>> broken in several patches. This is set 1 of 4.
> >>>>>>>>>
> >>>>>>>>> HP BIOS Configuration driver purpose is to provide a driver supporting
> >>>>>>>>> the latest sysfs class firmware attributes framework allowing the user
> >>>>>>>>> to change BIOS settings and security solutions on HP Inc.’s commercial
> >>>>>>>>> notebooks.
> >>>>>>>>>
> >>>>>>>>> Many features of HP Commercial PC’s can be managed using Windows
> >>>>>>>>> Management Instrumentation (WMI). WMI is an implementation of Web-Based
> >>>>>>>>> Enterprise Management (WBEM) that provides a standards-based interface
> >>>>>>>>> for changing and monitoring system settings. HP BISOCFG driver provides
> >>>>>>>>> a native Linux solution and the exposed features facilitates the
> >>>>>>>>> migration to Linux environments.
> >>>>>>>>>
> >>>>>>>>> The Linux security features to be provided in hp-bioscfg driver enables
> >>>>>>>>> managing the BIOS settings and security solutions via sysfs, a virtual
> >>>>>>>>> filesystem that can be used by user-mode applications. The new
> >>>>>>>>> documentation cover features such Secure Platform Management, Sure
> >>>>>>>>> Admin, and Sure Start. Each section provides security feature
> >>>>>>>>> description and identifies sysfs directories and files exposed by
> >>>>>>>>> the driver.
> >>>>>>>>>
> >>>>>>>>> Many HP Commercial PC’s include a feature called Secure Platform
> >>>>>>>>> Management (SPM), which replaces older password-based BIOS settings
> >>>>>>>>> management with public key cryptography. PC secure product management
> >>>>>>>>> begins when a target system is provisioned with cryptographic keys
> >>>>>>>>> that are used to ensure the integrity of communications between system
> >>>>>>>>> management utilities and the BIOS.
> >>>>>>>>>
> >>>>>>>>> HP Commercial PC’s have several BIOS settings that control its behaviour
> >>>>>>>>> and capabilities, many of which are related to security. To prevent
> >>>>>>>>> unauthorized changes to these settings, the system can be configured
> >>>>>>>>> to use a Sure Admin cryptographic signature-based authorization string
> >>>>>>>>> that the BIOS will use to verify authorization to modify the setting.
> >>>>>>>>>
> >>>>>>>>> Signed-off-by: Jorge Lopez <jorge.lopez2@xxxxxx>
> >>>>>>>>>
> >>>>>>>>> ---
> >>>>>>>>> Based on the latest platform-drivers-x86.git/for-next
> >>>>>>>>> ---
> >>>>>>>>> .../x86/hp/hp-bioscfg/biosattr-interface.c | 285 ++++++++
> >>>>>>>>> drivers/platform/x86/hp/hp-bioscfg/bioscfg.h | 671 ++++++++++++++++++
> >>>>>>>>> .../x86/hp/hp-bioscfg/enum-attributes.c | 521 ++++++++++++++
> >>>>>>>>> 3 files changed, 1477 insertions(+)
> >>>>>>>>> create mode 100644 drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> >>>>>>>>> create mode 100644 drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
> >>>>>>>>> create mode 100644 drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
> >>>>>>>>>
> >>>>>>>>> diff --git a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> >>>>>>>>> new file mode 100644
> >>>>>>>>> index 000000000000..f0c919bf3ab0
> >>>>>>>>> --- /dev/null
> >>>>>>>>> +++ b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> >>>>>>>>> @@ -0,0 +1,285 @@
> >>>>>>>>> +// SPDX-License-Identifier: GPL-2.0
> >>>>>>>>> +/*
> >>>>>>>>> + * Functions corresponding to methods under BIOS interface GUID
> >>>>>>>>> + * for use with hp-bioscfg driver.
> >>>>>>>>> + *
> >>>>>>>>> + * Copyright (c) 2022 Hewlett-Packard Inc.
> >>>>>>>>> + */
> >>>>>>>>> +
> >>>>>>>>> +#include <linux/wmi.h>
> >>>>>>>>> +#include "bioscfg.h"
> >>>>>>>>> +
> >>>>>>>>> +#define SET_DEFAULT_VALUES_METHOD_ID 0x02
> >>>>>>>>> +#define SET_BIOS_DEFAULTS_METHOD_ID 0x03
> >>>>>>>>> +#define SET_ATTRIBUTE_METHOD_ID 0x04
> >>>>>>>>> +
> >>>>>>>>> +/*
> >>>>>>>>> + * set_attribute() - Update an attribute value
> >>>>>>>>> + * @a_name: The attribute name
> >>>>>>>>> + * @a_value: The attribute value
> >>>>>>>>> + *
> >>>>>>>>> + * Sets an attribute to new value
> >>>>>>>>> + */
> >>>>>>>>> +int hp_set_attribute(const char *a_name, const char *a_value)
> >>>>>>>>> +{
> >>>>>>>>> + size_t security_area_size;
> >>>>>>>>> + size_t a_name_size, a_value_size;
> >>>>>>>>> + u16 *buffer = NULL;
> >>>>>>>>> + u16 *start = NULL;
> >>>>>>>>> + int buffer_size;
> >>>>>>>>
> >>>>>>>> You have 2 spaces between int and buffer_size here, please drop
> >>>>>>>> one.
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>> + int ret;
> >>>>>>>>> + int instance;
> >>>>>>>>> + char *auth_empty_value = " ";
> >>>>>>>>> +
> >>>>>>>>> + mutex_lock(&bioscfg_drv.mutex);
> >>>>>>>>> + if (!bioscfg_drv.bios_attr_wdev) {
> >>>>>>>>> + ret = -ENODEV;
> >>>>>>>>> + goto out_set_attribute;
> >>>>>>>>> + }
> >>>>>>>>> +
> >>>>>>>>> + instance = get_password_instance_for_type(SETUP_PASSWD);
> >>>>>>>>> + if (instance < 0)
> >>>>>>>>> + goto out_set_attribute;
> >>>>>>>>> +
> >>>>>>>>> + if (strlen(bioscfg_drv.password_data[instance].current_password) == 0)
> >>>>>>>>> + strncpy(bioscfg_drv.password_data[instance].current_password,
> >>>>>>>>> + auth_empty_value,
> >>>>>>>>> + sizeof(bioscfg_drv.password_data[instance].current_password));
> >>>>>>>>
> >>>>>>>> strncpy does not guarantee 0 termination of the destination buffer,
> >>>>>>>> please use strscpy.
> >>>>>>>>
> >>>>>>>>> +
> >>>>>>>>> + a_name_size = calculate_string_buffer(a_name);
> >>>>>>>>> + a_value_size = calculate_string_buffer(a_value);
> >>>>>>>>> + security_area_size = calculate_security_buffer(bioscfg_drv.password_data[instance].current_password);
> >>>>>>>>> + buffer_size = a_name_size + a_value_size + security_area_size;
> >>>>>>>>> +
> >>>>>>>>> + buffer = kzalloc(buffer_size, GFP_KERNEL);
> >>>>>>>>> + if (!buffer) {
> >>>>>>>>> + ret = -ENOMEM;
> >>>>>>>>> + goto out_set_attribute;
> >>>>>>>>> + }
> >>>>>>>>> +
> >>>>>>>>> + /* build variables to set */
> >>>>>>>>> + start = buffer;
> >>>>>>>>> + start = ascii_to_utf16_unicode(start, a_name);
> >>>>>>>>> + if (!start)
> >>>>>>>>> + goto out_set_attribute;
> >>>>>>>>> +
> >>>>>>>>> + start = ascii_to_utf16_unicode(start, a_value);
> >>>>>>>>> + if (!start)
> >>>>>>>>> + goto out_set_attribute;
> >>>>>>>>> +
> >>>>>>>>> + populate_security_buffer(start, bioscfg_drv.password_data[instance].current_password);
> >>>>>>>>> + ret = hp_wmi_set_bios_setting(buffer, buffer_size);
> >>>>>>>>> +
> >>>>>>>>> +
> >>>>>>>>> +out_set_attribute:
> >>>>>>>>> + kfree(buffer);
> >>>>>>>>> + mutex_unlock(&bioscfg_drv.mutex);
> >>>>>>>>> + return ret;
> >>>>>>>>> +}
> >>>>>>>>> +
> >>>>>>>>> +/*
> >>>>>>>>> + * hp_wmi_perform_query
> >>>>>>>>> + *
> >>>>>>>>> + * query: The commandtype (enum hp_wmi_commandtype)
> >>>>>>>>> + * write: The command (enum hp_wmi_command)
> >>>>>>>>> + * buffer: Buffer used as input and/or output
> >>>>>>>>> + * insize: Size of input buffer
> >>>>>>>>> + * outsize: Size of output buffer
> >>>>>>>>> + *
> >>>>>>>>> + * returns zero on success
> >>>>>>>>> + * an HP WMI query specific error code (which is positive)
> >>>>>>>>> + * -EINVAL if the query was not successful at all
> >>>>>>>>> + * -EINVAL if the output buffer size exceeds buffersize
> >>>>>>>>> + *
> >>>>>>>>> + * Note: The buffersize must at least be the maximum of the input and output
> >>>>>>>>> + * size. E.g. Battery info query is defined to have 1 byte input
> >>>>>>>>> + * and 128 byte output. The caller would do:
> >>>>>>>>> + * buffer = kzalloc(128, GFP_KERNEL);
> >>>>>>>>> + * ret = hp_wmi_perform_query(HPWMI_BATTERY_QUERY, HPWMI_READ, buffer, 1, 128)
> >>>>>>>>> + */
> >>>>>>>>> +int hp_wmi_perform_query(int query, enum hp_wmi_command command, void *buffer, int insize, int outsize)
> >>>>>>>>> +{
> >>>>>>>>> + struct acpi_buffer input, output = { ACPI_ALLOCATE_BUFFER, NULL };
> >>>>>>>>> + struct bios_return *bios_return;
> >>>>>>>>> + union acpi_object *obj = NULL;
> >>>>>>>>> + struct bios_args *args = NULL;
> >>>>>>>>> + int mid, actual_insize, actual_outsize;
> >>>>>>>>> + size_t bios_args_size;
> >>>>>>>>> + int ret;
> >>>>>>>>> +
> >>>>>>>>> + mid = encode_outsize_for_pvsz(outsize);
> >>>>>>>>> + if (WARN_ON(mid < 0))
> >>>>>>>>> + return mid;
> >>>>>>>>> +
> >>>>>>>>> + actual_insize = insize;
> >>>>>>>>> + bios_args_size = struct_size(args, data, insize);
> >>>>>>>>> + args = kmalloc(bios_args_size, GFP_KERNEL);
> >>>>>>>>> + if (!args)
> >>>>>>>>> + return -ENOMEM;
> >>>>>>>>> +
> >>>>>>>>> + input.length = bios_args_size;
> >>>>>>>>> + input.pointer = args;
> >>>>>>>>> +
> >>>>>>>>> + args->signature = 0x55434553;
> >>>>>>>>> + args->command = command;
> >>>>>>>>> + args->commandtype = query;
> >>>>>>>>> + args->datasize = insize;
> >>>>>>>>> + memcpy(args->data, buffer, flex_array_size(args, data, insize));
> >>>>>>>>> +
> >>>>>>>>> + ret = wmi_evaluate_method(HP_WMI_BIOS_GUID, 0, mid, &input, &output);
> >>>>>>>>> + bioscfg_drv.last_wmi_status = ret;
> >>>>>>>>> + if (ret)
> >>>>>>>>> + goto out_free;
> >>>>>>>>> +
> >>>>>>>>> + obj = output.pointer;
> >>>>>>>>> + if (!obj) {
> >>>>>>>>> + ret = -EINVAL;
> >>>>>>>>> + goto out_free;
> >>>>>>>>> + }
> >>>>>>>>> +
> >>>>>>>>
> >>>>>>>> You need to check the type of obj here before dereferencing
> >>>>>>>> obj as if it is a buffer.
> >>>>>>>>
> >>>>>>>>> + bios_return = (struct bios_return *)obj->buffer.pointer;
> >>>>>>>>> + ret = bios_return->return_code;
> >>>>>>>>> + bioscfg_drv.last_wmi_status = ret;
> >>>>>>>>> + if (ret) {
> >>>>>>>>> + if (ret != HPWMI_RET_UNKNOWN_COMMAND &&
> >>>>>>>>> + ret != HPWMI_RET_UNKNOWN_CMDTYPE)
> >>>>>>>>> + pr_warn("query 0x%x returned error 0x%x\n", query, ret);
> >>>>>>>>> + goto out_free;
> >>>>>>>>> + }
> >>>>>>>>> +
> >>>>>>>>> + /* Ignore output data of zero size */
> >>>>>>>>> + if (!outsize)
> >>>>>>>>> + goto out_free;
> >>>>>>>>> +
> >>>>>>>>> + actual_outsize = min(outsize, (int)(obj->buffer.length - sizeof(*bios_return)));
> >>>>>>>>> + memcpy(buffer, obj->buffer.pointer + sizeof(*bios_return), actual_outsize);
> >>>>>>>>> + memset(buffer + actual_outsize, 0, outsize - actual_outsize);
> >>>>>>>>> +
> >>>>>>>>> +out_free:
> >>>>>>>>> + kfree(obj);
> >>>>>>>>> + kfree(args);
> >>>>>>>>> + return ret;
> >>>>>>>>> +}
> >>>>>>>>> +
> >>>>>>>>> +/*
> >>>>>>>>> + * ascii_to_utf16_unicode - Convert ascii string to UTF-16 unicode
> >>>>>>>>> + *
> >>>>>>>>> + * @p: Unicode buffer address
> >>>>>>>>> + * @str: string to convert to unicode
> >>>>>>>>> + *
> >>>>>>>>> + * Returns a void pointer to the buffer containing unicode string
> >>>>>>>>> + */
> >>>>>>>>> +void *ascii_to_utf16_unicode(u16 *p, const u8 *str)
> >>>>>>>>> +{
> >>>>>>>>> + int len = strlen(str);
> >>>>>>>>> + int ret;
> >>>>>>>>> +
> >>>>>>>>> + /*
> >>>>>>>>> + * Add null character when reading an empty string
> >>>>>>>>> + */
> >>>>>>>>> + if (len == 0) {
> >>>>>>>>> + *p++ = 2;
> >>>>>>>>> + *p++ = (u8)0x00;
> >>>>>>>>> + return p;
> >>>>>>>>
> >>>>>>>> This does not match with calculate_string_buffer() which will
> >>>>>>>> return 2 for a 0 length string while you are using 4 bytes here.
> >>>>>>>>
> >>>>>>>> I guess this may also be why you need to use " " for
> >>>>>>>> auth_empty_value above, so as to avoid this bug.
> >>>>>>>>
> >>>>>>> HP BIOS expects 2 characters when an empty string is being converted
> >>>>>>> to u16 hence the reason for returning 2 instead of zero. This is an
> >>>>>>> intended behavior and needed when allocating a buffer and writing to
> >>>>>>> BIOS.
> >>>>>>
> >>>>>> Right I understand that, it wants 2 characters for the 16 bit length
> >>>>>> word, but why not write 0 to that 16 bit length word. Why actually
> >>>>>> say the string-buffer length is 2 bytes long / and then write
> >>>>>> a 16-bit word with value 0?
> >>>>>>
> >>>>>> What you are doing now creates a 4 byte buffer like this:
> >>>>>>
> >>>>>> u8 buf[4] = { 0x02, 0x00, 0x00, 0x00 }
> >>>>>>
> >>>>>> Why not just create a 2 byte buffer like this:
> >>>>>>
> >>>>>> u8 buf[2] = { 0x00, 0x00 }
> >>>>>>
> >>>>>> ?
> >>>>>>
> >>>>>>
> >>>>>> Also I'm wondering why the empty auth string is " " and
> >>>>>> not "" ?
> >>>>>>
> >>>>>>
> >>>>>
> >>>>> The string returned for an empty string is 4 bytes. The returned
> >>>>> string includes two bytes for the string size in bytes and the
> >>>>> remaining bytes are the string.
> >>>>> Size = 0x02, 0x00
> >>>>> String = 0x00, 0x00
> >>>>>
> >>>>> All strings return include the string size in bytes followed by the u16 string
> >>>>
> >>>> Right I understand that, but why is the "String = 0x00, 0x00"
> >>>> there ? All the non-0-length strings are not 0 terminated,
> >>>> why does the zero length string needs to be specified as length 2
> >>>> (1 u16) and then have that u16 be a 0 terminator ?
> >>>>
> >>> It is a specific format required by BIOS for any zero-length strings.
> >>> I don't know the reason why BIOS wants that format.
> >>>
> >>>
> >>>> Have you tried just using Size[2] = 0x00, 0x00 and String[0] for
> >>>> an empty string?
> >>>>
> >>>
> >>> I tried during the development process and each time the data is
> >>> rejected by BIOS.
> >>
> >> Ok, well in that case you are going to need your own
> >> ascii_to_utf16_unicode() to handle the weird case for the
> >> 0 sized string, so no need to move the dell-wmi-sysman versions
> >> to the shared wmi code.
> >>
> >> But please do start with a copy of the Dell function and then
> >> add the special case for the 0 len string, since the original
> >> version above does not properly handle errors.
> >>
> >> Also this means you need to update the hp calculate_string_buffer()
> >> copy to properly return 4 rather then 2 for the bufsize for
> >> a 0 length string.
> >>
> >
> > I will do so. Thanks.
> > BTW, changes requested for sysman.c will require changes to two other
> > DELL source files;
> > biosattr-interface.c and passwordattr-interface.c.
> > All I can do is to verify it compiles ok.
>
> Note that since you now need a special version to deal
> with the 0 length string weirdness, you can just make
> a private copy of the dell functions into the hp code
> and then modify that to add the special case for the
> 0 length strings.
>
> So there is no longer a need to move the dell versions
> out into wmi.c since the hp code will need a modified
> version anyways (so the code cannot be shared).
>
Understood. I just wanted to make sure.
Thanks
> Regards,
>
> Hans
>
