The following commit has been merged into the x86/urgent branch of tip: Commit-ID: ac7c06acaa3738b38e83815ac0f07140ad320f13 Gitweb: https://git.kernel.org/tip/ac7c06acaa3738b38e83815ac0f07140ad320f13 Author: Nikunj A Dadhania <nikunj@xxxxxxx> AuthorDate: Thu, 06 Mar 2025 19:17:21 +11:00 Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx> CommitterDate: Fri, 07 Mar 2025 13:34:25 +01:00 virt: sev-guest: Allocate request data dynamically 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@xxxxxxxxx Signed-off-by: Nikunj A Dadhania <nikunj@xxxxxxx> Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxx> Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/20250307013700.437505-2-aik@xxxxxxx --- 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 264b652..23ac177 100644 --- a/drivers/virt/coco/sev-guest/sev-guest.c +++ b/drivers/virt/coco/sev-guest/sev-guest.c @@ -38,12 +38,6 @@ 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; }; /* @@ -71,7 +65,7 @@ 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 = {}; @@ -80,6 +74,10 @@ 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; @@ -116,7 +114,7 @@ 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 = {}; @@ -136,6 +134,10 @@ 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; @@ -168,7 +170,7 @@ 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 = {}; @@ -178,6 +180,10 @@ 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;
