This is a note to let you know that I've just added the patch titled ASoC: SOF: ipc3-dtrace: uninitialized data in dfsentry_trace_filter_write() to the 6.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: asoc-sof-ipc3-dtrace-uninitialized-data-in-dfsentry_.patch and it can be found in the queue-6.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 4d081eb7ade047c783eff167d9362c5a23f905d4 Author: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Date: Fri Jul 7 14:25:23 2023 +0300 ASoC: SOF: ipc3-dtrace: uninitialized data in dfsentry_trace_filter_write() [ Upstream commit 469e2f28c2cbee2430058c1c9bb6d1675d7195fb ] 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@xxxxxxxxxx> Link: https://lore.kernel.org/r/74148292-ce4d-4e01-a1a7-921e6767da14@moroto.mountain Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/sound/soc/sof/ipc3-dtrace.c b/sound/soc/sof/ipc3-dtrace.c index 1d3bca2d28dd6..35da85a45a9ae 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)