From d668de80d065e7796d2fb31cf2c66084850baa2f Mon Sep 17 00:00:00 2001
From: Jan Engelmohr <jan.engelmohr@mailbox.tu-dresden.de>
Date: Tue, 26 Jul 2016 18:11:29 +0200
Subject: 3.10.74 -> 3.10.75

---
 fs/proc/task_mmu.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

(limited to 'fs/proc')

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index eebdc27fa..9995bb1e7 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1221,9 +1221,19 @@ out:
 	return ret;
 }
 
+static int pagemap_open(struct inode *inode, struct file *file)
+{
+	/* do not disclose physical addresses to unprivileged
+	   userspace (closes a rowhammer attack vector) */
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+	return 0;
+}
+
 const struct file_operations proc_pagemap_operations = {
 	.llseek		= mem_lseek, /* borrow this */
 	.read		= pagemap_read,
+	.open		= pagemap_open,
 };
 #endif /* CONFIG_PROC_PAGE_MONITOR */
 
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