From: Miaoqing Pan <miaoqing@xxxxxxxxxxxxxx> [ Upstream commit ee0a47186e2fa9aa1c56cadcea470ca0ba8c8692 ] When the user sets count to zero the string buffer would remain completely uninitialized which causes the kernel to parse its own stack data, potentially leading to an info leak. In addition to that, the string might be not terminated properly when the user data does not contain a 0-terminator. Signed-off-by: Miaoqing Pan <miaoqing@xxxxxxxxxxxxxx> Reviewed-by: Christoph Böhmwalder <christoph@xxxxxxxxxxxxxx> Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> --- drivers/net/wireless/ath/ath9k/tx99.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/net/wireless/ath/ath9k/tx99.c b/drivers/net/wireless/ath/ath9k/tx99.c index 1fa7f844b5da..8e9480cc33e1 100644 --- a/drivers/net/wireless/ath/ath9k/tx99.c +++ b/drivers/net/wireless/ath/ath9k/tx99.c @@ -179,6 +179,9 @@ static ssize_t write_file_tx99(struct file *file, const char __user *user_buf, ssize_t len; int r; + if (count < 1) + return -EINVAL; + if (sc->cur_chan->nvifs > 1) return -EOPNOTSUPP; @@ -186,6 +189,8 @@ static ssize_t write_file_tx99(struct file *file, const char __user *user_buf, if (copy_from_user(buf, user_buf, len)) return -EFAULT; + buf[len] = '\0'; + if (strtobool(buf, &start)) return -EINVAL; -- 2.11.0