[PATCH] printk: fix kernel msg leakage in syslog_print_all function；

[taolan]

From: t00264981 <taolan@xxxxxxxxxx>

This function applies for memory but does not initialize the memory,and
then invokes copy_to_user to copy the memory to the user space, which
causes kernel information leaks.

[ 148.439660] kernel memory leak value 0xffffff80aed972bc at
0xffffffd37f00a000 to 0x704b883e74

Signed-off-by: t00264981 <taolan@xxxxxxxxxx>
---
 kernel/printk/printk.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index da03c15ecc89..22d7d821909d 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1591,7 +1591,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
 	u64 seq;
 	bool time;
 
-	text = kmalloc(CONSOLE_LOG_MAX, GFP_KERNEL);
+	text = kzalloc(CONSOLE_LOG_MAX, GFP_KERNEL);
 	if (!text)
 		return -ENOMEM;
 
-- 
2.18.0.huawei.25