On Fri, 27 Apr 2012, James Woodcock wrote:
> > -void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
> > +int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
> > {
> > struct hidraw *dev = hid->hidraw;
> > struct hidraw_list *list;
> > + int ret = 0;
> >
> > list_for_each_entry(list, &dev->list, node) {
> > - list->buffer[list->head].value = kmemdup(data, len,
> GFP_ATOMIC);
> > + if (!(list->buffer[list->head].value = kmemdup(data,
> len, GFP_ATOMIC))) {
> > + ret = -ENOMEM;
> > + break;
> > + }
> > list->buffer[list->head].len = len;
> > list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE -
> 1);
> > kill_fasync(&list->fasync, SIGIO, POLL_IN);
> > }
> >
> > wake_up_interruptible(&dev->wait);
> > + return ret;
> > }
> >
>
> What happens if there is more than 1 element in the list and kmemdup
> fails
> halfway through the list? Will the allocated memory leak the next time
> hirdaw_report_event() is called?
Unfortunately it was too late already yesterday and I sent out a wrong
version of the patch.
The one I actually propose is below (it contains handling of NULL value
after read() has been woken up).
From: Jiri Kosina <jkosina@xxxxxxx>
Subject: [PATCH] HID: hidraw: add proper error handling to raw event reporting
If kmemdup() in hidraw_report_event() fails, we are not propagating
this fact properly.
Let hidraw_report_event() and hid_report_raw_event() return an error
value to the caller.
Reported-by: Oliver Neukum <oneukum@xxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
---
drivers/hid/hid-core.c | 16 +++++++++++-----
drivers/hid/hidraw.c | 19 +++++++++++++------
include/linux/hid.h | 2 +-
include/linux/hidraw.h | 4 ++--
4 files changed, 27 insertions(+), 14 deletions(-)
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 8be458b..0cddcaa 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1032,7 +1032,7 @@ static struct hid_report *hid_get_report(struct hid_report_enum *report_enum,
return report;
}
-void hid_report_raw_event(struct hid_device *hid, int type, u8 *data, int size,
+int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, int size,
int interrupt)
{
struct hid_report_enum *report_enum = hid->report_enum + type;
@@ -1040,10 +1040,11 @@ void hid_report_raw_event(struct hid_device *hid, int type, u8 *data, int size,
unsigned int a;
int rsize, csize = size;
u8 *cdata = data;
+ int ret = 0;
report = hid_get_report(report_enum, data);
if (!report)
- return;
+ goto out;
if (report_enum->numbered) {
cdata++;
@@ -1063,14 +1064,19 @@ void hid_report_raw_event(struct hid_device *hid, int type, u8 *data, int size,
if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event)
hid->hiddev_report_event(hid, report);
- if (hid->claimed & HID_CLAIMED_HIDRAW)
- hidraw_report_event(hid, data, size);
+ if (hid->claimed & HID_CLAIMED_HIDRAW) {
+ ret = hidraw_report_event(hid, data, size);
+ if (ret)
+ goto out;
+ }
for (a = 0; a < report->maxfield; a++)
hid_input_field(hid, report->field[a], cdata, interrupt);
if (hid->claimed & HID_CLAIMED_INPUT)
hidinput_report_event(hid, report);
+out:
+ return ret;
}
EXPORT_SYMBOL_GPL(hid_report_raw_event);
@@ -1147,7 +1153,7 @@ nomem:
}
}
- hid_report_raw_event(hid, type, data, size, interrupt);
+ ret = hid_report_raw_event(hid, type, data, size, interrupt);
unlock:
up(&hid->driver_lock);
diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index cf7d6d5..36fa77b 100644
--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -87,11 +87,13 @@ static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count,
len = list->buffer[list->tail].len > count ?
count : list->buffer[list->tail].len;
- if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
- ret = -EFAULT;
- goto out;
+ if (list->buffer[list->tail].value) {
+ if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ ret = len;
}
- ret = len;
kfree(list->buffer[list->tail].value);
list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
@@ -437,19 +439,24 @@ static const struct file_operations hidraw_ops = {
.llseek = noop_llseek,
};
-void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
+int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
{
struct hidraw *dev = hid->hidraw;
struct hidraw_list *list;
+ int ret = 0;
list_for_each_entry(list, &dev->list, node) {
- list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
+ if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
+ ret = -ENOMEM;
+ break;
+ }
list->buffer[list->head].len = len;
list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
kill_fasync(&list->fasync, SIGIO, POLL_IN);
}
wake_up_interruptible(&dev->wait);
+ return ret;
}
EXPORT_SYMBOL_GPL(hidraw_report_event);
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 3a95da6..58b3857 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -896,7 +896,7 @@ static inline int hid_hw_power(struct hid_device *hdev, int level)
return hdev->ll_driver->power ? hdev->ll_driver->power(hdev, level) : 0;
}
-void hid_report_raw_event(struct hid_device *hid, int type, u8 *data, int size,
+int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, int size,
int interrupt);
extern int hid_generic_init(void);
diff --git a/include/linux/hidraw.h b/include/linux/hidraw.h
index 4b88e69..9cdc9b6 100644
--- a/include/linux/hidraw.h
+++ b/include/linux/hidraw.h
@@ -76,13 +76,13 @@ struct hidraw_list {
#ifdef CONFIG_HIDRAW
int hidraw_init(void);
void hidraw_exit(void);
-void hidraw_report_event(struct hid_device *, u8 *, int);
+int hidraw_report_event(struct hid_device *, u8 *, int);
int hidraw_connect(struct hid_device *);
void hidraw_disconnect(struct hid_device *);
#else
static inline int hidraw_init(void) { return 0; }
static inline void hidraw_exit(void) { }
-static inline void hidraw_report_event(struct hid_device *hid, u8 *data, int len) { }
+static inline int hidraw_report_event(struct hid_device *hid, u8 *data, int len) { }
static inline int hidraw_connect(struct hid_device *hid) { return -1; }
static inline void hidraw_disconnect(struct hid_device *hid) { }
#endif
--
Jiri Kosina
SUSE Labs
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