On 7/3/25 12:36, Alexey Kardashevskiy wrote:
From: Nikunj A Dadhania nikunj@amd.com
Commit ae596615d93d ("virt: sev-guest: Reduce the scope of SNP command mutex") narrowed the command mutex scope to snp_send_guest_request. However, GET_REPORT, GET_DERIVED_KEY, and GET_EXT_REPORT share the req structure in snp_guest_dev. Without the mutex protection, concurrent requests can overwrite each other's data. Fix it by dynamically allocating the request structure.
Fixes: ae596615d93d ("virt: sev-guest: Reduce the scope of SNP command mutex") Cc: stable@vger.kernel.org Reported-by: andreas.stuehrk@yaxi.tech Closes: https://github.com/AMDESE/AMDSEV/issues/265 Signed-off-by: Nikunj A Dadhania nikunj@amd.com
oh. forgot:
Signed-off-by: Alexey Kardashevskiy aik@amd.com
drivers/virt/coco/sev-guest/sev-guest.c | 24 ++++++++++++-------- 1 file changed, 15 insertions(+), 9 deletions(-)
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c index ddec5677e247..4699fdc9ed44 100644 --- a/drivers/virt/coco/sev-guest/sev-guest.c +++ b/drivers/virt/coco/sev-guest/sev-guest.c @@ -39,12 +39,6 @@ struct snp_guest_dev { struct miscdevice misc; struct snp_msg_desc *msg_desc;
- union {
struct snp_report_req report;struct snp_derived_key_req derived_key;struct snp_ext_report_req ext_report;- } req; };
/* @@ -72,7 +66,7 @@ struct snp_req_resp { static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg) {
- struct snp_report_req *report_req = &snp_dev->req.report;
- struct snp_report_req *report_req __free(kfree) = NULL; struct snp_msg_desc *mdesc = snp_dev->msg_desc; struct snp_report_resp *report_resp; struct snp_guest_req req = {};
@@ -81,6 +75,10 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io if (!arg->req_data || !arg->resp_data) return -EINVAL;
- report_req = kzalloc(sizeof(*report_req), GFP_KERNEL_ACCOUNT);
- if (!report_req)
return -ENOMEM;- if (copy_from_user(report_req, (void __user *)arg->req_data, sizeof(*report_req))) return -EFAULT;
@@ -117,7 +115,7 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg) {
- struct snp_derived_key_req *derived_key_req = &snp_dev->req.derived_key;
- struct snp_derived_key_req *derived_key_req __free(kfree) = NULL; struct snp_derived_key_resp derived_key_resp = {0}; struct snp_msg_desc *mdesc = snp_dev->msg_desc; struct snp_guest_req req = {};
@@ -137,6 +135,10 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque if (sizeof(buf) < resp_len) return -ENOMEM;
- derived_key_req = kzalloc(sizeof(*derived_key_req), GFP_KERNEL_ACCOUNT);
- if (!derived_key_req)
return -ENOMEM;- if (copy_from_user(derived_key_req, (void __user *)arg->req_data, sizeof(*derived_key_req))) return -EFAULT;
@@ -169,7 +171,7 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques struct snp_req_resp *io) {
- struct snp_ext_report_req *report_req = &snp_dev->req.ext_report;
- struct snp_ext_report_req *report_req __free(kfree) = NULL; struct snp_msg_desc *mdesc = snp_dev->msg_desc; struct snp_report_resp *report_resp; struct snp_guest_req req = {};
@@ -179,6 +181,10 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques if (sockptr_is_null(io->req_data) || sockptr_is_null(io->resp_data)) return -EINVAL;
- report_req = kzalloc(sizeof(*report_req), GFP_KERNEL_ACCOUNT);
- if (!report_req)
return -ENOMEM;- if (copy_from_sockptr(report_req, io->req_data, sizeof(*report_req))) return -EFAULT;