[v1] tracing: Prevent bad count for tracing_cpumask_write

[PATCH] tracing: Prevent bad count for tracing_cpumask_write

Lizhi Xu posted 1 patch 1 year ago

Diff against v2
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kernel/trace/trace.c | 3 +++
1 file changed, 3 insertions(+)

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[PATCH] tracing: Prevent bad count for tracing_cpumask_write

Posted by Lizhi Xu 1 year ago

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

Reported-by: syzbot+0aecfd34fb878546f3fd@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=0aecfd34fb878546f3fd
Tested-by: syzbot+0aecfd34fb878546f3fd@syzkaller.appspotmail.com
Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
---
 kernel/trace/trace.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index be62f0ea1814..109f301549b8 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5225,6 +5225,9 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf,
 	cpumask_var_t tracing_cpumask_new;
 	int err;
 
+	if (count == 0 || count << PAGE_SHIFT > MAX_PAGE_ORDER)
+		return -EINVAL;
+
 	if (!zalloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
 		return -ENOMEM;
 
-- 
2.43.0