Commit c5e81e67 authored by Jan Kiszka's avatar Jan Kiszka Committed by Ard Biesheuvel
Browse files

efi: stmm: Fix incorrect buffer allocation method 



The communication buffer allocated by setup_mm_hdr() is later on passed
to tee_shm_register_kernel_buf(). The latter expects those buffers to be
contiguous pages, but setup_mm_hdr() just uses kmalloc(). That can cause
various corruptions or BUGs, specifically since commit 9aec2fb0
("slab: allocate frozen pages"), though it was broken before as well.

Fix this by using alloc_pages_exact() instead of kmalloc().

Fixes: c44b6be6 ("efi: Add tee-based EFI variable driver")
Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Acked-by: default avatarIlias Apalodimas <ilias.apalodimas@linaro.org>
Acked-by: default avatarSumit Garg <sumit.garg@oss.qualcomm.com>
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
parent 8f5ae30d

drivers/firmware/efi/stmm/tee_stmm_efi.c

+12 −9
Original line number Diff line number Diff line
@@ -143,6 +143,10 @@ static efi_status_t mm_communicate(u8 *comm_buf, size_t payload_size) 
	return var_hdr->ret_status;

}



#define COMM_BUF_SIZE(__payload_size)	(MM_COMMUNICATE_HEADER_SIZE + \

					 MM_VARIABLE_COMMUNICATE_SIZE + \

					 (__payload_size))



/**

 * setup_mm_hdr() -	Allocate a buffer for StandAloneMM and initialize the

 *			header data.
@@ -173,9 +177,8 @@ static void *setup_mm_hdr(u8 **dptr, size_t payload_size, size_t func, 
		return NULL;

	}



	comm_buf = kzalloc(MM_COMMUNICATE_HEADER_SIZE +

				   MM_VARIABLE_COMMUNICATE_SIZE + payload_size,

			   GFP_KERNEL);

	comm_buf = alloc_pages_exact(COMM_BUF_SIZE(payload_size),

				     GFP_KERNEL | __GFP_ZERO);

	if (!comm_buf) {

		*ret = EFI_OUT_OF_RESOURCES;

		return NULL;
@@ -239,7 +242,7 @@ static efi_status_t get_max_payload(size_t *size) 
	 */

	*size -= 2;

out:

	kfree(comm_buf);

	free_pages_exact(comm_buf, COMM_BUF_SIZE(payload_size));

	return ret;

}
@@ -282,7 +285,7 @@ static efi_status_t get_property_int(u16 *name, size_t name_size, 
	memcpy(var_property, &smm_property->property, sizeof(*var_property));



out:

	kfree(comm_buf);

	free_pages_exact(comm_buf, COMM_BUF_SIZE(payload_size));

	return ret;

}
@@ -347,7 +350,7 @@ static efi_status_t tee_get_variable(u16 *name, efi_guid_t *vendor, 
	memcpy(data, (u8 *)var_acc->name + var_acc->name_size,

	       var_acc->data_size);

out:

	kfree(comm_buf);

	free_pages_exact(comm_buf, COMM_BUF_SIZE(payload_size));

	return ret;

}
@@ -404,7 +407,7 @@ static efi_status_t tee_get_next_variable(unsigned long *name_size, 
	memcpy(name, var_getnext->name, var_getnext->name_size);



out:

	kfree(comm_buf);

	free_pages_exact(comm_buf, COMM_BUF_SIZE(payload_size));

	return ret;

}
@@ -467,7 +470,7 @@ static efi_status_t tee_set_variable(efi_char16_t *name, efi_guid_t *vendor, 
	ret = mm_communicate(comm_buf, payload_size);

	dev_dbg(pvt_data.dev, "Set Variable %s %d %lx\n", __FILE__, __LINE__, ret);

out:

	kfree(comm_buf);

	free_pages_exact(comm_buf, COMM_BUF_SIZE(payload_size));

	return ret;

}
@@ -507,7 +510,7 @@ static efi_status_t tee_query_variable_info(u32 attributes, 
	*max_variable_size = mm_query_info->max_variable_size;



out:

	kfree(comm_buf);

	free_pages_exact(comm_buf, COMM_BUF_SIZE(payload_size));

	return ret;

}