From 26fb87ffa9d90fb16ca1b2b262f38d93bdcee934 Mon Sep 17 00:00:00 2001 From: Steffen Eiden Date: Mon, 6 Nov 2023 13:49:22 +0100 Subject: s390/uvdevice: Report additional-data length for attestation Additional data length in the attestation request is an in/out variable. Software provides the capacity of the buffer. Upon successful request, firmware reports the actual bytes written to the additional data in that field. This information is lost, as the length field was not copied back to userspace before. Attestation might fail, if user space did not specify the exact amount of needed bytes required, as this length is part of the attestation measurement. Signed-off-by: Steffen Eiden Reviewed-by: Claudio Imbrenda Reviewed-by: Janosch Frank Link: https://lore.kernel.org/r/20231106124922.3032370-1-seiden@linux.ibm.com Message-Id: <20231106124922.3032370-1-seiden@linux.ibm.com> Signed-off-by: Janosch Frank --- drivers/s390/char/uvdevice.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/s390') diff --git a/drivers/s390/char/uvdevice.c b/drivers/s390/char/uvdevice.c index 144cd2e03590..42c9f77f8da0 100644 --- a/drivers/s390/char/uvdevice.c +++ b/drivers/s390/char/uvdevice.c @@ -109,6 +109,7 @@ static int uvio_copy_attest_result_to_user(struct uv_cb_attest *uvcb_attest, struct uvio_attest *uvio_attest) { struct uvio_attest __user *user_uvio_attest = (void __user *)uv_ioctl->argument_addr; + u32 __user *user_buf_add_len = (u32 __user *)&user_uvio_attest->add_data_len; void __user *user_buf_add = (void __user *)uvio_attest->add_data_addr; void __user *user_buf_meas = (void __user *)uvio_attest->meas_addr; void __user *user_buf_uid = &user_uvio_attest->config_uid; @@ -117,6 +118,8 @@ static int uvio_copy_attest_result_to_user(struct uv_cb_attest *uvcb_attest, return -EFAULT; if (add_data && copy_to_user(user_buf_add, add_data, uvio_attest->add_data_len)) return -EFAULT; + if (put_user(uvio_attest->add_data_len, user_buf_add_len)) + return -EFAULT; if (copy_to_user(user_buf_uid, uvcb_attest->config_uid, sizeof(uvcb_attest->config_uid))) return -EFAULT; return 0; -- cgit v1.2.3