72 lines
2.4 KiB
Diff
72 lines
2.4 KiB
Diff
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From: Jan Beulich <JBeulich@suse.com>
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Date: Tue, 22 Nov 2016 05:56:51 -0700
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Subject: [PATCH] xen: fix ioreq handling
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Avoid double fetches and bounds check size to avoid overflowing
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internal variables.
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This is CVE-2016-9381 / XSA-197.
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Reported-by: yanghongke <yanghongke@huawei.com>
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Signed-off-by: Jan Beulich <jbeulich@suse.com>
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Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
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Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
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(cherry picked from commit b85f9dfdb156ae2a2a52f39a36e9f1f270614cd2)
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---
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xen-hvm.c | 16 +++++++++++++++-
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1 file changed, 15 insertions(+), 1 deletion(-)
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diff --git a/xen-hvm.c b/xen-hvm.c
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index 2f348ed..097007d 100644
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--- a/xen-hvm.c
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+++ b/xen-hvm.c
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@@ -810,6 +810,10 @@ static void cpu_ioreq_pio(ioreq_t *req)
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trace_cpu_ioreq_pio(req, req->dir, req->df, req->data_is_ptr, req->addr,
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req->data, req->count, req->size);
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+ if (req->size > sizeof(uint32_t)) {
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+ hw_error("PIO: bad size (%u)", req->size);
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+ }
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+
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if (req->dir == IOREQ_READ) {
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if (!req->data_is_ptr) {
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req->data = do_inp(req->addr, req->size);
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@@ -846,6 +850,10 @@ static void cpu_ioreq_move(ioreq_t *req)
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trace_cpu_ioreq_move(req, req->dir, req->df, req->data_is_ptr, req->addr,
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req->data, req->count, req->size);
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+ if (req->size > sizeof(req->data)) {
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+ hw_error("MMIO: bad size (%u)", req->size);
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+ }
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+
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if (!req->data_is_ptr) {
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if (req->dir == IOREQ_READ) {
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for (i = 0; i < req->count; i++) {
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@@ -1010,11 +1018,13 @@ static int handle_buffered_iopage(XenIOState *state)
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req.df = 1;
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req.type = buf_req->type;
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req.data_is_ptr = 0;
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+ xen_rmb();
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qw = (req.size == 8);
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if (qw) {
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buf_req = &buf_page->buf_ioreq[(rdptr + 1) %
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IOREQ_BUFFER_SLOT_NUM];
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req.data |= ((uint64_t)buf_req->data) << 32;
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+ xen_rmb();
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}
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handle_ioreq(state, &req);
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@@ -1045,7 +1055,11 @@ static void cpu_handle_ioreq(void *opaque)
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handle_buffered_iopage(state);
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if (req) {
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- handle_ioreq(state, req);
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+ ioreq_t copy = *req;
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+
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+ xen_rmb();
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+ handle_ioreq(state, ©);
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+ req->data = copy.data;
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if (req->state != STATE_IOREQ_INPROCESS) {
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fprintf(stderr, "Badness in I/O request ... not in service?!: "
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