[PATCH 4.14 29/68] Drivers: hv: vmbus: Check for ring when getting debug info

From: Greg Kroah-Hartman
Date: Tue Jan 29 2019 - 06:58:06 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Dexuan Cui <decui@xxxxxxxxxxxxx>

commit ba50bf1ce9a51fc97db58b96d01306aa70bc3979 upstream.

fc96df16a1ce is good and can already fix the "return stack garbage" issue,
but let's also improve hv_ringbuffer_get_debuginfo(), which would silently
return stack garbage, if people forget to check channel->state or
ring_info->ring_buffer, when using the function in the future.

Having an error check in the function would eliminate the potential risk.

Add a Fixes tag to indicate the patch depdendency.

Fixes: fc96df16a1ce ("Drivers: hv: vmbus: Return -EINVAL for the sys files for unopened channels")
Cc: stable@xxxxxxxxxxxxxxx
Cc: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Signed-off-by: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/hv/ring_buffer.c | 29 +++++++-------
drivers/hv/vmbus_drv.c | 91 +++++++++++++++++++++++++++++++----------------
include/linux/hyperv.h | 5 +-
3 files changed, 78 insertions(+), 47 deletions(-)

--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -141,26 +141,25 @@ static u32 hv_copyto_ringbuffer(
}

/* Get various debug metrics for the specified ring buffer. */
-void hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,
- struct hv_ring_buffer_debug_info *debug_info)
+int hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,
+ struct hv_ring_buffer_debug_info *debug_info)
{
u32 bytes_avail_towrite;
u32 bytes_avail_toread;

- if (ring_info->ring_buffer) {
- hv_get_ringbuffer_availbytes(ring_info,
- &bytes_avail_toread,
- &bytes_avail_towrite);
+ if (!ring_info->ring_buffer)
+ return -EINVAL;

- debug_info->bytes_avail_toread = bytes_avail_toread;
- debug_info->bytes_avail_towrite = bytes_avail_towrite;
- debug_info->current_read_index =
- ring_info->ring_buffer->read_index;
- debug_info->current_write_index =
- ring_info->ring_buffer->write_index;
- debug_info->current_interrupt_mask =
- ring_info->ring_buffer->interrupt_mask;
- }
+ hv_get_ringbuffer_availbytes(ring_info,
+ &bytes_avail_toread,
+ &bytes_avail_towrite);
+ debug_info->bytes_avail_toread = bytes_avail_toread;
+ debug_info->bytes_avail_towrite = bytes_avail_towrite;
+ debug_info->current_read_index = ring_info->ring_buffer->read_index;
+ debug_info->current_write_index = ring_info->ring_buffer->write_index;
+ debug_info->current_interrupt_mask
+ = ring_info->ring_buffer->interrupt_mask;
+ return 0;
}
EXPORT_SYMBOL_GPL(hv_ringbuffer_get_debuginfo);

--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -297,12 +297,16 @@ static ssize_t out_intr_mask_show(struct
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info outbound;
+ int ret;

if (!hv_dev->channel)
return -ENODEV;
- if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
- return -EINVAL;
- hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
+
+ ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
+ &outbound);
+ if (ret < 0)
+ return ret;
+
return sprintf(buf, "%d\n", outbound.current_interrupt_mask);
}
static DEVICE_ATTR_RO(out_intr_mask);
@@ -312,12 +316,15 @@ static ssize_t out_read_index_show(struc
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info outbound;
+ int ret;

if (!hv_dev->channel)
return -ENODEV;
- if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
- return -EINVAL;
- hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
+
+ ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
+ &outbound);
+ if (ret < 0)
+ return ret;
return sprintf(buf, "%d\n", outbound.current_read_index);
}
static DEVICE_ATTR_RO(out_read_index);
@@ -328,12 +335,15 @@ static ssize_t out_write_index_show(stru
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info outbound;
+ int ret;

if (!hv_dev->channel)
return -ENODEV;
- if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
- return -EINVAL;
- hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
+
+ ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
+ &outbound);
+ if (ret < 0)
+ return ret;
return sprintf(buf, "%d\n", outbound.current_write_index);
}
static DEVICE_ATTR_RO(out_write_index);
@@ -344,12 +354,15 @@ static ssize_t out_read_bytes_avail_show
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info outbound;
+ int ret;

if (!hv_dev->channel)
return -ENODEV;
- if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
- return -EINVAL;
- hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
+
+ ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
+ &outbound);
+ if (ret < 0)
+ return ret;
return sprintf(buf, "%d\n", outbound.bytes_avail_toread);
}
static DEVICE_ATTR_RO(out_read_bytes_avail);
@@ -360,12 +373,15 @@ static ssize_t out_write_bytes_avail_sho
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info outbound;
+ int ret;

if (!hv_dev->channel)
return -ENODEV;
- if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
- return -EINVAL;
- hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
+
+ ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
+ &outbound);
+ if (ret < 0)
+ return ret;
return sprintf(buf, "%d\n", outbound.bytes_avail_towrite);
}
static DEVICE_ATTR_RO(out_write_bytes_avail);
@@ -375,12 +391,15 @@ static ssize_t in_intr_mask_show(struct
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info inbound;
+ int ret;

if (!hv_dev->channel)
return -ENODEV;
- if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
- return -EINVAL;
- hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+
+ ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+ if (ret < 0)
+ return ret;
+
return sprintf(buf, "%d\n", inbound.current_interrupt_mask);
}
static DEVICE_ATTR_RO(in_intr_mask);
@@ -390,12 +409,15 @@ static ssize_t in_read_index_show(struct
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info inbound;
+ int ret;

if (!hv_dev->channel)
return -ENODEV;
- if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
- return -EINVAL;
- hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+
+ ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+ if (ret < 0)
+ return ret;
+
return sprintf(buf, "%d\n", inbound.current_read_index);
}
static DEVICE_ATTR_RO(in_read_index);
@@ -405,12 +427,15 @@ static ssize_t in_write_index_show(struc
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info inbound;
+ int ret;

if (!hv_dev->channel)
return -ENODEV;
- if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
- return -EINVAL;
- hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+
+ ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+ if (ret < 0)
+ return ret;
+
return sprintf(buf, "%d\n", inbound.current_write_index);
}
static DEVICE_ATTR_RO(in_write_index);
@@ -421,12 +446,15 @@ static ssize_t in_read_bytes_avail_show(
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info inbound;
+ int ret;

if (!hv_dev->channel)
return -ENODEV;
- if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
- return -EINVAL;
- hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+
+ ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+ if (ret < 0)
+ return ret;
+
return sprintf(buf, "%d\n", inbound.bytes_avail_toread);
}
static DEVICE_ATTR_RO(in_read_bytes_avail);
@@ -437,12 +465,15 @@ static ssize_t in_write_bytes_avail_show
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info inbound;
+ int ret;

if (!hv_dev->channel)
return -ENODEV;
- if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
- return -EINVAL;
- hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+
+ ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+ if (ret < 0)
+ return ret;
+
return sprintf(buf, "%d\n", inbound.bytes_avail_towrite);
}
static DEVICE_ATTR_RO(in_write_bytes_avail);
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1130,8 +1130,9 @@ struct hv_ring_buffer_debug_info {
u32 bytes_avail_towrite;
};

-void hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,
- struct hv_ring_buffer_debug_info *debug_info);
+
+int hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,
+ struct hv_ring_buffer_debug_info *debug_info);

/* Vmbus interface */
#define vmbus_driver_register(driver) \