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[Qemu-devel] [PATCH 1/2] ide: Ignore reads during PIO in and writes duri
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 1/2] ide: Ignore reads during PIO in and writes during PIO out |
Date: |
Mon, 4 Jul 2011 17:39:31 +0200 |
This fixes https://bugs.launchpad.net/qemu/+bug/786209:
When the DRQ_STAT bit is set, the IDE core permits both data reads
and data writes, regardless of whether the current transfer was
initiated as a read or write.
This potentially leaks uninitialized host memory into the guest,
if, before doing anything else to an IDE device, the guest begins a
write transaction (e.g. WIN_WRITE), but then *reads* from the IO
port instead of writing to it.
Signed-off-by: Kevin Wolf <address@hidden>
---
hw/ide/core.c | 40 ++++++++++++++++++++++++++++++++--------
1 files changed, 32 insertions(+), 8 deletions(-)
diff --git a/hw/ide/core.c b/hw/ide/core.c
index ca17a43..2c5395b 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -56,6 +56,7 @@ static const int smart_attributes[][12] = {
};
static int ide_handle_rw_error(IDEState *s, int error, int op);
+static void ide_dummy_transfer_stop(IDEState *s);
static void padstr(char *str, const char *src, int len)
{
@@ -1532,15 +1533,32 @@ void ide_cmd_write(void *opaque, uint32_t addr,
uint32_t val)
bus->cmd = val;
}
+static bool ide_is_pio_out(IDEState *s)
+{
+ if (s->end_transfer_func == ide_sector_write ||
+ s->end_transfer_func == ide_atapi_cmd) {
+ return false;
+ } else if (s->end_transfer_func == ide_sector_read ||
+ s->end_transfer_func == ide_transfer_stop ||
+ s->end_transfer_func == ide_atapi_cmd_reply_end ||
+ s->end_transfer_func == ide_dummy_transfer_stop) {
+ return true;
+ }
+
+ abort();
+}
+
void ide_data_writew(void *opaque, uint32_t addr, uint32_t val)
{
IDEBus *bus = opaque;
IDEState *s = idebus_active_if(bus);
uint8_t *p;
- /* PIO data access allowed only when DRQ bit is set */
- if (!(s->status & DRQ_STAT))
+ /* PIO data access allowed only when DRQ bit is set. The result of a write
+ * during PIO out is indeterminate, just ignore it. */
+ if (!(s->status & DRQ_STAT) || ide_is_pio_out(s)) {
return;
+ }
p = s->data_ptr;
*(uint16_t *)p = le16_to_cpu(val);
@@ -1557,9 +1575,11 @@ uint32_t ide_data_readw(void *opaque, uint32_t addr)
uint8_t *p;
int ret;
- /* PIO data access allowed only when DRQ bit is set */
- if (!(s->status & DRQ_STAT))
+ /* PIO data access allowed only when DRQ bit is set. The result of a read
+ * during PIO in is indeterminate, return 0 and don't move forward. */
+ if (!(s->status & DRQ_STAT) || !ide_is_pio_out(s)) {
return 0;
+ }
p = s->data_ptr;
ret = cpu_to_le16(*(uint16_t *)p);
@@ -1576,9 +1596,11 @@ void ide_data_writel(void *opaque, uint32_t addr,
uint32_t val)
IDEState *s = idebus_active_if(bus);
uint8_t *p;
- /* PIO data access allowed only when DRQ bit is set */
- if (!(s->status & DRQ_STAT))
+ /* PIO data access allowed only when DRQ bit is set. The result of a write
+ * during PIO out is indeterminate, just ignore it. */
+ if (!(s->status & DRQ_STAT) || ide_is_pio_out(s)) {
return;
+ }
p = s->data_ptr;
*(uint32_t *)p = le32_to_cpu(val);
@@ -1595,9 +1617,11 @@ uint32_t ide_data_readl(void *opaque, uint32_t addr)
uint8_t *p;
int ret;
- /* PIO data access allowed only when DRQ bit is set */
- if (!(s->status & DRQ_STAT))
+ /* PIO data access allowed only when DRQ bit is set. The result of a read
+ * during PIO in is indeterminate, return 0 and don't move forward. */
+ if (!(s->status & DRQ_STAT) || !ide_is_pio_out(s)) {
return 0;
+ }
p = s->data_ptr;
ret = cpu_to_le32(*(uint32_t *)p);
--
1.7.6
- [Qemu-devel] [PATCH 1/2] ide: Ignore reads during PIO in and writes during PIO out,
Kevin Wolf <=