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From: Jan Beulich <jbeulich@suse.com>
Subject: xen: fix ioreq handling
Avoid double fetches and bounds check size to avoid overflowing
internal variables.
This is XSA-197.
Reported-by: yanghongke <yanghongke@huawei.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Ian Jackson <ian.jackson@eu.citrix.com>
--- a/i386-dm/helper2.c
+++ b/tools/qemu-xen-traditional/i386-dm/helper2.c
@@ -375,6 +375,11 @@ static void cpu_ioreq_pio(CPUState *env,
{
uint32_t i;
+ if (req->size > sizeof(unsigned long)) {
+ fprintf(stderr, "PIO: bad size (%u)\n", req->size);
+ exit(-1);
+ }
+
if (req->dir == IOREQ_READ) {
if (!req->data_is_ptr) {
req->data = do_inp(env, req->addr, req->size);
@@ -404,6 +409,11 @@ static void cpu_ioreq_move(CPUState *env
{
uint32_t i;
+ if (req->size > sizeof(req->data)) {
+ fprintf(stderr, "MMIO: bad size (%u)\n", req->size);
+ exit(-1);
+ }
+
if (!req->data_is_ptr) {
if (req->dir == IOREQ_READ) {
for (i = 0; i < req->count; i++) {
@@ -516,11 +526,13 @@ static int __handle_buffered_iopage(CPUS
req.df = 1;
req.type = buf_req->type;
req.data_is_ptr = 0;
+ xen_rmb();
qw = (req.size == 8);
if (qw) {
buf_req = &buffered_io_page->buf_ioreq[(rdptr + 1) %
IOREQ_BUFFER_SLOT_NUM];
req.data |= ((uint64_t)buf_req->data) << 32;
+ xen_rmb();
}
__handle_ioreq(env, &req);
@@ -552,7 +564,11 @@ static void cpu_handle_ioreq(void *opaqu
__handle_buffered_iopage(env);
if (req) {
- __handle_ioreq(env, req);
+ ioreq_t copy = *req;
+
+ xen_rmb();
+ __handle_ioreq(env, ©);
+ req->data = copy.data;
if (req->state != STATE_IOREQ_INPROCESS) {
fprintf(logfile, "Badness in I/O request ... not in service?!: "
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