[PATCH] memory:bugxfix panic on cat or write /dev/kmem

[chenjie6]

From: chenjie <chenj...@huawei.com>

cat /dev/kmem and echo > /dev/kmem will lead panic

Signed-off-by: chenjie <chenj...@huawei.com>
---
 drivers/char/mem.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 71025c2..4bdde28 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -412,6 +412,8 @@ static ssize_t read_kmem(struct file *file, char __user 
*buf,
                         * by the kernel or data corruption may occur
                         */
                        kbuf = xlate_dev_kmem_ptr((void *)p);
+                       if (!kbuf)
+                               return -EFAULT;
 
                        if (copy_to_user(buf, kbuf, sz))
                                return -EFAULT;
@@ -482,6 +484,11 @@ static ssize_t do_write_kmem(unsigned long p, const char 
__user *buf,
                 * corruption may occur.
                 */
                ptr = xlate_dev_kmem_ptr((void *)p);
+               if (!ptr) {
+                       if (written)
+                               break;
+                       return -EFAULT;
+               }
 
                copied = copy_from_user(ptr, buf, sz);
                if (copied) {
-- 
1.8.0