qxl: don't abort on guest trigerrable ring indices mismatch

Signed-off-by: Alon Levy <alevy@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This commit is contained in:
Alon Levy 2012-04-25 12:13:21 +03:00 committed by Gerd Hoffmann
parent 2fce7edf46
commit 0b81c478cf

View File

@ -27,28 +27,42 @@
#include "qxl.h"
/*
* NOTE: SPICE_RING_PROD_ITEM accesses memory on the pci bar and as
* such can be changed by the guest, so to avoid a guest trigerrable
* abort we just set qxl_guest_bug and set the return to NULL. Still
* it may happen as a result of emulator bug as well.
*/
#undef SPICE_RING_PROD_ITEM
#define SPICE_RING_PROD_ITEM(r, ret) { \
#define SPICE_RING_PROD_ITEM(qxl, r, ret) { \
typeof(r) start = r; \
typeof(r) end = r + 1; \
uint32_t prod = (r)->prod & SPICE_RING_INDEX_MASK(r); \
typeof(&(r)->items[prod]) m_item = &(r)->items[prod]; \
if (!((uint8_t*)m_item >= (uint8_t*)(start) && (uint8_t*)(m_item + 1) <= (uint8_t*)(end))) { \
abort(); \
qxl_guest_bug(qxl, "SPICE_RING_PROD_ITEM indices mismatch " \
"! %p <= %p < %p", (uint8_t *)start, \
(uint8_t *)m_item, (uint8_t *)end); \
ret = NULL; \
} else { \
ret = &m_item->el; \
} \
ret = &m_item->el; \
}
#undef SPICE_RING_CONS_ITEM
#define SPICE_RING_CONS_ITEM(r, ret) { \
#define SPICE_RING_CONS_ITEM(qxl, r, ret) { \
typeof(r) start = r; \
typeof(r) end = r + 1; \
uint32_t cons = (r)->cons & SPICE_RING_INDEX_MASK(r); \
typeof(&(r)->items[cons]) m_item = &(r)->items[cons]; \
if (!((uint8_t*)m_item >= (uint8_t*)(start) && (uint8_t*)(m_item + 1) <= (uint8_t*)(end))) { \
abort(); \
qxl_guest_bug(qxl, "SPICE_RING_CONS_ITEM indices mismatch " \
"! %p <= %p < %p", (uint8_t *)start, \
(uint8_t *)m_item, (uint8_t *)end); \
ret = NULL; \
} else { \
ret = &m_item->el; \
} \
ret = &m_item->el; \
}
#undef ALIGN
@ -343,7 +357,8 @@ static void init_qxl_ram(PCIQXLDevice *d)
SPICE_RING_INIT(&d->ram->cmd_ring);
SPICE_RING_INIT(&d->ram->cursor_ring);
SPICE_RING_INIT(&d->ram->release_ring);
SPICE_RING_PROD_ITEM(&d->ram->release_ring, item);
SPICE_RING_PROD_ITEM(d, &d->ram->release_ring, item);
assert(item);
*item = 0;
qxl_ring_set_dirty(d);
}
@ -559,8 +574,10 @@ static int interface_get_command(QXLInstance *sin, struct QXLCommandExt *ext)
if (SPICE_RING_IS_EMPTY(ring)) {
return false;
}
trace_qxl_ring_command_get(qxl->id, qxl_mode_to_string(qxl->mode));
SPICE_RING_CONS_ITEM(ring, cmd);
SPICE_RING_CONS_ITEM(qxl, ring, cmd);
if (!cmd) {
return false;
}
ext->cmd = *cmd;
ext->group_id = MEMSLOT_GROUP_GUEST;
ext->flags = qxl->cmdflags;
@ -572,6 +589,7 @@ static int interface_get_command(QXLInstance *sin, struct QXLCommandExt *ext)
qxl->guest_primary.commands++;
qxl_track_command(qxl, ext);
qxl_log_command(qxl, "cmd", ext);
trace_qxl_ring_command_get(qxl->id, qxl_mode_to_string(qxl->mode));
return true;
default:
return false;
@ -630,7 +648,10 @@ static inline void qxl_push_free_res(PCIQXLDevice *d, int flush)
if (notify) {
qxl_send_events(d, QXL_INTERRUPT_DISPLAY);
}
SPICE_RING_PROD_ITEM(ring, item);
SPICE_RING_PROD_ITEM(d, ring, item);
if (!item) {
return;
}
*item = 0;
d->num_free_res = 0;
d->last_release = NULL;
@ -656,7 +677,10 @@ static void interface_release_resource(QXLInstance *sin,
* pci bar 0, $command.release_info
*/
ring = &qxl->ram->release_ring;
SPICE_RING_PROD_ITEM(ring, item);
SPICE_RING_PROD_ITEM(qxl, ring, item);
if (!item) {
return;
}
if (*item == 0) {
/* stick head into the ring */
id = ext.info->id;
@ -695,7 +719,10 @@ static int interface_get_cursor_command(QXLInstance *sin, struct QXLCommandExt *
if (SPICE_RING_IS_EMPTY(ring)) {
return false;
}
SPICE_RING_CONS_ITEM(ring, cmd);
SPICE_RING_CONS_ITEM(qxl, ring, cmd);
if (!cmd) {
return false;
}
ext->cmd = *cmd;
ext->group_id = MEMSLOT_GROUP_GUEST;
ext->flags = qxl->cmdflags;