This doesn't check how many bytes the simple_write_to_buffer() writes to the buffer. The only thing that we know is that the first byte is initialized and the last byte of the buffer is set to NUL. However the middle bytes could be uninitialized.

There is no need to use simple_write_to_buffer(). This code does not support partial writes but instead passes "pos = 0" as the starting offset regardless of what the user passed as "*ppos". Just use the copy_from_user() function and initialize the whole buffer.

Fixes: 671e0b90051e ("ASoC: SOF: Clone the trace code to ipc3-dtrace as fw_tracing implementation") Signed-off-by: Dan Carpenter dan.carpenter@linaro.org --- The nicer thing to do would have been to use strndup_user() but that comes with a small risk of breaking user space and I can't test this so I didn't do that.

sound/soc/sof/ipc3-dtrace.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/sound/soc/sof/ipc3-dtrace.c b/sound/soc/sof/ipc3-dtrace.c index 1d3bca2d28dd..35da85a45a9a 100644 --- a/sound/soc/sof/ipc3-dtrace.c +++ b/sound/soc/sof/ipc3-dtrace.c @@ -186,7 +186,6 @@ static ssize_t dfsentry_trace_filter_write(struct file *file, const char __user struct snd_sof_dfsentry *dfse = file->private_data; struct sof_ipc_trace_filter_elem *elems = NULL; struct snd_sof_dev *sdev = dfse->sdev; - loff_t pos = 0; int num_elems; char *string; int ret; @@ -201,11 +200,11 @@ static ssize_t dfsentry_trace_filter_write(struct file *file, const char __user if (!string) return -ENOMEM;

- /* assert null termination */ - string[count] = 0; - ret = simple_write_to_buffer(string, count, &pos, from, count); - if (ret < 0) + if (copy_from_user(string, from, count)) { + ret = -EFAULT; goto error; + } + string[count] = '\0';

ret = trace_filter_parse(sdev, string, &num_elems, &elems); if (ret < 0)