diff options
| author | Hugo Lefeuvre <hle@owl.eu.com> | 2018-06-13 21:04:38 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-06-17 09:05:12 +0200 |
| commit | 6de4ef65a8c6f53ce7eef06666410bc3b6e4b624 (patch) | |
| tree | 9197acae27ad892fe84bd81fcb02a3884c1caa5c /drivers/staging/pi433 | |
| parent | 0d6485282a2eb8839ecb98d4da2dc1c35aab7223 (diff) | |
staging: pi433: fix race condition in pi433_ioctl
In the PI433_IOC_WR_TX_CFG case in pi433_ioctl, instance->tx_cfg is
modified via
copy_from_user(&instance->tx_cfg, argp, sizeof(struct pi433_tx_cfg)))
without any kind of synchronization. In the case where two threads
would execute this same command concurrently the tx_cfg field might
enter in an inconsistent state.
Additionally: if ioctl(PI433_IOC_WR_TX_CFG) and write() execute
concurrently the tx config might be modified while it is being
copied to the fifo, resulting in potential data corruption.
Fix: Get instance->tx_cfg_lock before modifying tx config in the
PI433_IOC_WR_TX_CFG case in pi433_ioctl.
Also, do not copy data directly from user space to instance->tx_cfg.
Instead use a temporary buffer allowing future checks for correctness
of copied data and simpler code.
Signed-off-by: Hugo Lefeuvre <hle@owl.eu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging/pi433')
| -rw-r--r-- | drivers/staging/pi433/pi433_if.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/staging/pi433/pi433_if.c b/drivers/staging/pi433/pi433_if.c index b061f77dda41..94e0bfcec991 100644 --- a/drivers/staging/pi433/pi433_if.c +++ b/drivers/staging/pi433/pi433_if.c @@ -880,6 +880,7 @@ pi433_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) int retval = 0; struct pi433_instance *instance; struct pi433_device *device; + struct pi433_tx_cfg tx_cfg; void __user *argp = (void __user *)arg; /* Check type and command number */ @@ -902,9 +903,11 @@ pi433_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) return -EFAULT; break; case PI433_IOC_WR_TX_CFG: - if (copy_from_user(&instance->tx_cfg, argp, - sizeof(struct pi433_tx_cfg))) + if (copy_from_user(&tx_cfg, argp, sizeof(struct pi433_tx_cfg))) return -EFAULT; + mutex_lock(&device->tx_fifo_lock); + memcpy(&instance->tx_cfg, &tx_cfg, sizeof(struct pi433_tx_cfg)); + mutex_unlock(&device->tx_fifo_lock); break; case PI433_IOC_RD_RX_CFG: if (copy_to_user(argp, &device->rx_cfg, |