5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jeongjun Park <aha310510@xxxxxxxxx>
[ Upstream commit 44feafbaa66ec86232b123bb8437a6a262442025 ]
iowarrior_read() uses the iowarrior dev structure, but does not use any
lock on the structure. This can cause various bugs including data-races,
so it is more appropriate to use a mutex lock to safely protect the
iowarrior dev structure. When using a mutex lock, you should split the
branch to prevent blocking when the O_NONBLOCK flag is set.
In addition, it is unnecessary to check for NULL on the iowarrior dev
structure obtained by reading file->private_data. Therefore, it is
better to remove the check.
Fixes: 946b960d13c1 ("USB: add driver for iowarrior devices.")
Signed-off-by: Jeongjun Park <aha310510@xxxxxxxxx>
Link: https://lore.kernel.org/r/20240919103403.3986-1-aha310510@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/usb/misc/iowarrior.c | 46 ++++++++++++++++++++++++++++--------
1 file changed, 36 insertions(+), 10 deletions(-)
diff --git a/drivers/usb/misc/iowarrior.c b/drivers/usb/misc/iowarrior.c
index c366a65fbd802..f23291da25498 100644
--- a/drivers/usb/misc/iowarrior.c
+++ b/drivers/usb/misc/iowarrior.c
@@ -277,28 +277,45 @@ static ssize_t iowarrior_read(struct file *file, char __user *buffer,
struct iowarrior *dev;
int read_idx;
int offset;
+ int retval;
dev = file->private_data;
+ if (file->f_flags & O_NONBLOCK) {
+ retval = mutex_trylock(&dev->mutex);
+ if (!retval)
+ return -EAGAIN;
+ } else {
+ retval = mutex_lock_interruptible(&dev->mutex);
+ if (retval)
+ return -ERESTARTSYS;
+ }
+
/* verify that the device wasn't unplugged */
- if (!dev || !dev->present)
- return -ENODEV;
+ if (!dev->present) {
+ retval = -ENODEV;
+ goto exit;
+ }
dev_dbg(&dev->interface->dev, "minor %d, count = %zd\n",
dev->minor, count);
/* read count must be packet size (+ time stamp) */
if ((count != dev->report_size)
- && (count != (dev->report_size + 1)))
- return -EINVAL;
+ && (count != (dev->report_size + 1))) {
+ retval = -EINVAL;
+ goto exit;
+ }
/* repeat until no buffer overrun in callback handler occur */
do {
atomic_set(&dev->overflow_flag, 0);
if ((read_idx = read_index(dev)) == -1) {
/* queue empty */
- if (file->f_flags & O_NONBLOCK)
- return -EAGAIN;
+ if (file->f_flags & O_NONBLOCK) {
+ retval = -EAGAIN;
+ goto exit;
+ }
else {
//next line will return when there is either new data, or the device is unplugged
int r = wait_event_interruptible(dev->read_wait,
@@ -309,28 +326,37 @@ static ssize_t iowarrior_read(struct file *file, char __user *buffer,
-1));
if (r) {
//we were interrupted by a signal
- return -ERESTART;
+ retval = -ERESTART;
+ goto exit;
}
if (!dev->present) {
//The device was unplugged
- return -ENODEV;
+ retval = -ENODEV;
+ goto exit;
}
if (read_idx == -1) {
// Can this happen ???
- return 0;
+ retval = 0;
+ goto exit;
}
}
}
offset = read_idx * (dev->report_size + 1);
if (copy_to_user(buffer, dev->read_queue + offset, count)) {
- return -EFAULT;
+ retval = -EFAULT;
+ goto exit;
}
} while (atomic_read(&dev->overflow_flag));
read_idx = ++read_idx == MAX_INTERRUPT_BUFFER ? 0 : read_idx;
atomic_set(&dev->read_idx, read_idx);
+ mutex_unlock(&dev->mutex);
return count;
+
+exit:
+ mutex_unlock(&dev->mutex);
+ return retval;
}
/*
--
2.43.0
