6.13-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nikunj A Dadhania nikunj@amd.com
commit ac7c06acaa3738b38e83815ac0f07140ad320f13 upstream.
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") Closes: https://github.com/AMDESE/AMDSEV/issues/265 Reported-by: andreas.stuehrk@yaxi.tech Signed-off-by: Nikunj A Dadhania nikunj@amd.com Signed-off-by: Alexey Kardashevskiy aik@amd.com Signed-off-by: Borislav Petkov (AMD) bp@alien8.de Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20250307013700.437505-2-aik@amd.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/virt/coco/sev-guest/sev-guest.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-)
--- a/drivers/virt/coco/sev-guest/sev-guest.c +++ b/drivers/virt/coco/sev-guest/sev-guest.c @@ -41,12 +41,6 @@ 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; };
/* @@ -390,7 +384,7 @@ 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 = {}; @@ -399,6 +393,10 @@ static int get_report(struct snp_guest_d 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;
@@ -435,7 +433,7 @@ e_free:
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 = {}; @@ -455,6 +453,10 @@ static int get_derived_key(struct snp_gu 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; @@ -487,7 +489,7 @@ static int get_ext_report(struct snp_gue 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 = {}; @@ -497,6 +499,10 @@ static int get_ext_report(struct snp_gue 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;