tracing: Fix permissions for the buffer_percent file

[PATCH] tracing: Fix permissions for the buffer_percent file

Posted by Ondrej Mosnacek 2 years, 9 months ago

This file defines both read and write operations, yet it is being
created as read-only. This means that it can't be written to without the
CAP_DAC_OVERRIDE capability. Fix the permissions to allow root to write
to it without the need to override DAC perms.

Fixes: 03329f993978 ("tracing: Add tracefs file buffer_percentage")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
---
 kernel/trace/trace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 45551c7b4c365..e278f4202a7ed 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -9655,7 +9655,7 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
 
 	tr->buffer_percent = 50;
 
-	trace_create_file("buffer_percent", TRACE_MODE_READ, d_tracer,
+	trace_create_file("buffer_percent", TRACE_MODE_WRITE, d_tracer,
 			tr, &buffer_percent_fops);
 
 	create_trace_options_dir(tr);
-- 
2.40.1

Re: [PATCH] tracing: Fix permissions for the buffer_percent file

Posted by Steven Rostedt 2 years, 9 months ago

On Wed,  3 May 2023 16:01:14 +0200
Ondrej Mosnacek <omosnace@redhat.com> wrote:

> This file defines both read and write operations, yet it is being
> created as read-only. This means that it can't be written to without the
> CAP_DAC_OVERRIDE capability. Fix the permissions to allow root to write
> to it without the need to override DAC perms.
> 
> Fixes: 03329f993978 ("tracing: Add tracefs file buffer_percentage")
> Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>

Applied. Thanks Ondrej!

-- Steve