From: Steffen Eiden Date: Mon, 6 Nov 2023 12:49:22 +0000 (+0100) Subject: s390/uvdevice: Report additional-data length for attestation X-Git-Tag: v6.8-rc1~78^2~14^2~3 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=26fb87ffa9d90fb16ca1b2b262f38d93bdcee934;p=thirdparty%2Flinux.git 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 --- diff --git a/drivers/s390/char/uvdevice.c b/drivers/s390/char/uvdevice.c index 144cd2e035909..42c9f77f8da0a 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;