2022-01-22 00:44:41

by Yuntao Wang

Subject: [PATCH] tracing: Use strim() to remove whitespace instead of doing it manually

The tracing_set_trace_write() function just removes the trailing whitespace
from the user supplied tracer name, but the leading whitespace should also
be removed.

In addition, if the user supplied tracer name contains only a few
whitespace characters, the first one will not be removed using the current
method, which results it a single whitespace character left in the buf.

To fix all of these issues, we use strim() to correctly remove both the
leading and trailing whitespace.

Signed-off-by: Yuntao Wang <[email protected]>
---
kernel/trace/trace.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a569a0cb81ee..a6e77db764cf 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6433,7 +6433,7 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf,
{
struct trace_array *tr = filp->private_data;
char buf[MAX_TRACER_SIZE+1];
- int i;
+ char *name;
size_t ret;
int err;

@@ -6447,11 +6447,9 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf,

buf[cnt] = 0;

- /* strip ending whitespace. */
- for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
- buf[i] = 0;
+ name = strim(buf);

- err = tracing_set_tracer(tr, buf);
+ err = tracing_set_tracer(tr, name);
if (err)
return err;

--
2.35.0.rc2

2022-05-25 20:37:37

by Steven Rostedt

Subject: Re: [PATCH] tracing: Use strim() to remove whitespace instead of doing it manually

On Fri, 21 Jan 2022 09:56:23 +0000
Yuntao Wang <[email protected]> wrote:

> The tracing_set_trace_write() function just removes the trailing whitespace
> from the user supplied tracer name, but the leading whitespace should also
> be removed.
>
> In addition, if the user supplied tracer name contains only a few
> whitespace characters, the first one will not be removed using the current
> method, which results it a single whitespace character left in the buf.
>
> To fix all of these issues, we use strim() to correctly remove both the
> leading and trailing whitespace.
>
> Signed-off-by: Yuntao Wang <[email protected]>

Added to my queue.

Thanks,

-- Steve