Re: [PATCH v3 03/11] tee: add TEE_IOCTL_PARAM_ATTR_TYPE_UBUF

[Amirreza Zarrabi <amirreza.zarrabi@oss.qualcomm.com>]

On 4/9/2025 4:41 PM, Jens Wiklander wrote:
> Hi Amirreza,
> 
> On Wed, Apr 9, 2025 at 2:28 AM Amirreza Zarrabi
> <amirreza.zarrabi@oss.qualcomm.com> wrote:
>>
>> Hi jens,
>>
>> On 4/8/2025 10:19 PM, Jens Wiklander wrote:
>>
>> Hi Amirreza,
>>
>> On Fri, Mar 28, 2025 at 3:48 AM Amirreza Zarrabi
>> <amirreza.zarrabi@oss.qualcomm.com> wrote:
>>
>> For drivers that can transfer data to the TEE without using shared
>> memory from client, it is necessary to receive the user address
>> directly, bypassing any processing by the TEE subsystem. Introduce
>> TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INPUT/OUTPUT/INOUT to represent
>> userspace buffers.
>>
>> Signed-off-by: Amirreza Zarrabi <amirreza.zarrabi@oss.qualcomm.com>
>> ---
>>  drivers/tee/tee_core.c   | 33 +++++++++++++++++++++++++++++++++
>>  include/linux/tee_drv.h  |  6 ++++++
>>  include/uapi/linux/tee.h | 22 ++++++++++++++++------
>>  3 files changed, 55 insertions(+), 6 deletions(-)
>>
>> Is this patch needed now that the QCOMTEE driver supports shared
>> memory? I prefer keeping changes to the ABI to a minimum.
>>
>> Cheers,
>> Jens
>>
>> Unfortunately, this is still required. QTEE supports two types of data transfer:
>> (1) using UBUF and (2) memory objects. Even with memory object support, some APIs still
>> expect to receive data using UBUF. For instance, to load a TA, QTEE offers two interfaces:
>> one where the TA binary is in UBUF and another where the TA binary is in a memory object.
> 
> Is this a limitation in the QTEE backend driver or on the secure side?
> Can it be fixed? I don't ask for changes in the ABI to the secure
> world since I assume you haven't made such changes while this patch
> set has evolved.
> 
> Cheers,
> Jens

The secure-side ABI supports passing data using memcpy to the same
buffer that contains the message for QTEE, rather than using a memory
object. Some services tend to use this approach for small data instead
of allocating a memory object. I have no choice but to expose this support.

Throughout the patchset, I have not made any change to the ABI but
tried to provide support for the memory object in a separate,
independent commit, distinct from the UBUF.

Best regards,
Amir

> 
>>
>> Best Regards,
>> Amir
>>
>> diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
>> index 22cc7d624b0c..bc862a11d437 100644
>> --- a/drivers/tee/tee_core.c
>> +++ b/drivers/tee/tee_core.c
>> @@ -404,6 +404,17 @@ static int params_from_user(struct tee_context *ctx, struct tee_param *params,
>>                         params[n].u.value.b = ip.b;
>>                         params[n].u.value.c = ip.c;
>>                         break;
>> +               case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INPUT:
>> +               case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_OUTPUT:
>> +               case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INOUT:
>> +                       params[n].u.ubuf.uaddr = u64_to_user_ptr(ip.a);
>> +                       params[n].u.ubuf.size = ip.b;
>> +
>> +                       if (!access_ok(params[n].u.ubuf.uaddr,
>> +                                      params[n].u.ubuf.size))
>> +                               return -EFAULT;
>> +
>> +                       break;
>>                 case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT:
>>                 case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
>>                 case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
>> @@ -472,6 +483,11 @@ static int params_to_user(struct tee_ioctl_param __user *uparams,
>>                             put_user(p->u.value.c, &up->c))
>>                                 return -EFAULT;
>>                         break;
>> +               case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_OUTPUT:
>> +               case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INOUT:
>> +                       if (put_user((u64)p->u.ubuf.size, &up->b))
>> +                               return -EFAULT;
>> +                       break;
>>                 case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
>>                 case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
>>                         if (put_user((u64)p->u.memref.size, &up->b))
>> @@ -672,6 +688,13 @@ static int params_to_supp(struct tee_context *ctx,
>>                         ip.b = p->u.value.b;
>>                         ip.c = p->u.value.c;
>>                         break;
>> +               case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INPUT:
>> +               case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_OUTPUT:
>> +               case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INOUT:
>> +                       ip.a = (u64)p->u.ubuf.uaddr;
>> +                       ip.b = p->u.ubuf.size;
>> +                       ip.c = 0;
>> +                       break;
>>                 case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT:
>>                 case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
>>                 case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
>> @@ -774,6 +797,16 @@ static int params_from_supp(struct tee_param *params, size_t num_params,
>>                         p->u.value.b = ip.b;
>>                         p->u.value.c = ip.c;
>>                         break;
>> +               case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_OUTPUT:
>> +               case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INOUT:
>> +                       p->u.ubuf.uaddr = u64_to_user_ptr(ip.a);
>> +                       p->u.ubuf.size = ip.b;
>> +
>> +                       if (!access_ok(params[n].u.ubuf.uaddr,
>> +                                      params[n].u.ubuf.size))
>> +                               return -EFAULT;
>> +
>> +                       break;
>>                 case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
>>                 case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
>>                         /*
>> diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
>> index ce23fd42c5d4..d773f91c6bdd 100644
>> --- a/include/linux/tee_drv.h
>> +++ b/include/linux/tee_drv.h
>> @@ -82,6 +82,11 @@ struct tee_param_memref {
>>         struct tee_shm *shm;
>>  };
>>
>> +struct tee_param_ubuf {
>> +       void * __user uaddr;
>> +       size_t size;
>> +};
>> +
>>  struct tee_param_value {
>>         u64 a;
>>         u64 b;
>> @@ -92,6 +97,7 @@ struct tee_param {
>>         u64 attr;
>>         union {
>>                 struct tee_param_memref memref;
>> +               struct tee_param_ubuf ubuf;
>>                 struct tee_param_value value;
>>         } u;
>>  };
>> diff --git a/include/uapi/linux/tee.h b/include/uapi/linux/tee.h
>> index d0430bee8292..3e9b1ec5dfde 100644
>> --- a/include/uapi/linux/tee.h
>> +++ b/include/uapi/linux/tee.h
>> @@ -151,6 +151,13 @@ struct tee_ioctl_buf_data {
>>  #define TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT        6
>>  #define TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT 7       /* input and output */
>>
>> +/*
>> + * These defines userspace buffer parameters.
>> + */
>> +#define TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INPUT   8
>> +#define TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_OUTPUT  9
>> +#define TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INOUT   10      /* input and output */
>> +
>>  /*
>>   * Mask for the type part of the attribute, leaves room for more types
>>   */
>> @@ -186,14 +193,17 @@ struct tee_ioctl_buf_data {
>>  /**
>>   * struct tee_ioctl_param - parameter
>>   * @attr: attributes
>> - * @a: if a memref, offset into the shared memory object, else a value parameter
>> - * @b: if a memref, size of the buffer, else a value parameter
>> + * @a: if a memref, offset into the shared memory object,
>> + *     else if a ubuf, address of the user buffer,
>> + *     else a value parameter
>> + * @b: if a memref or ubuf, size of the buffer, else a value parameter
>>   * @c: if a memref, shared memory identifier, else a value parameter
>>   *
>> - * @attr & TEE_PARAM_ATTR_TYPE_MASK indicates if memref or value is used in
>> - * the union. TEE_PARAM_ATTR_TYPE_VALUE_* indicates value and
>> - * TEE_PARAM_ATTR_TYPE_MEMREF_* indicates memref. TEE_PARAM_ATTR_TYPE_NONE
>> - * indicates that none of the members are used.
>> + * @attr & TEE_PARAM_ATTR_TYPE_MASK indicates if memref, ubuf, or value is
>> + * used in the union. TEE_PARAM_ATTR_TYPE_VALUE_* indicates value,
>> + * TEE_PARAM_ATTR_TYPE_MEMREF_* indicates memref, and TEE_PARAM_ATTR_TYPE_UBUF_*
>> + * indicates ubuf. TEE_PARAM_ATTR_TYPE_NONE indicates that none of the members
>> + * are used.
>>   *
>>   * Shared memory is allocated with TEE_IOC_SHM_ALLOC which returns an
>>   * identifier representing the shared memory object. A memref can reference
>>
>> --
>> 2.34.1
>>