tracing: Prevent bad count for tracing_cpumask_write

98feccbf · Lizhi Xu <[email protected]> · 2024-12-16 15:32:38 +08:00

If a large count is provided, it will trigger a warning in bitmap_parse_user.
Also check zero for it.

Cc: [email protected]
Fixes: 9e01c1b74c953 ("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]>

Commit: 98feccbf32cfdde8c722bc4587aaa60ee5ac33f0
Parents: 452f4b31

Changes

1 files changed · +3 −0

File	Status	Add	Del	Content
kernel/trace/trace.c	modified	+3	−0	View file

kernel/trace/trace.c

View file

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 957f941..f8aebcb 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5087,6 +5087,9 @@ 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;
 