tracing: Prevent bad count for tracing_cpumask_write

commit 98feccb upstream. If a large count is provided, it will trigger a warning in bitmap_parse_user. Also check zero for it. Cc: [email protected] Fixes: 9e01c1b ("cpumask: convert kernel trace functions") Link: https://lore.kernel.org/[email protected] Reported-by: [email protected] Closes: https://syzkaller.appspot.com/bug?extid=0aecfd34fb878546f3fd Tested-by: [email protected] Signed-off-by: Lizhi Xu <[email protected]> Signed-off-by: Steven Rostedt (Google) <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
P33M · Jan 2, 2025 · 1cca920 · 1cca920
1 parent a744146
commit 1cca920
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
@@ -5111,6 +5111,9 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf,
 	cpumask_var_t tracing_cpumask_new;
 	int err;
 
+	if (count == 0 || count > KMALLOC_MAX_SIZE)
+		return -EINVAL;
+
 	if (!zalloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
 		return -ENOMEM;