disp: msm: dsi: add check before buffer copy

This change adds a check for the length of the buffer
before copying it to avoid a buffer overflow.

Change-Id: I146895660be4060d9896706636257a57c6aef94f
Signed-off-by: Satya Rama Aditya Pinapala <[email protected]>

msm/dsi/dsi_ctrl.c

@@ -116,7 +116,7 @@ static ssize_t debugfs_state_info_read(struct file *file,
 			dsi_ctrl->clk_freq.pix_clk_rate,
 			dsi_ctrl->clk_freq.esc_clk_rate);
 
-	/* TODO: make sure that this does not exceed 4K */
+	len = min_t(size_t, len, SZ_4K);
 	if (copy_to_user(buff, buf, len)) {
 		kfree(buf);
 		return -EFAULT;
@@ -172,7 +172,7 @@ static ssize_t debugfs_reg_dump_read(struct file *file,
 	}
 
 
-	/* TODO: make sure that this does not exceed 4K */
+	len = min_t(size_t, len, SZ_4K);
 	if (copy_to_user(buff, buf, len)) {
 		kfree(buf);
 		return -EFAULT;