Patch "/proc/iomem: only expose physical resource addresses to privileged users" has been added to the 4.4-stable tree

Patch "/proc/iomem: only expose physical resource addresses to privileged users" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    /proc/iomem: only expose physical resource addresses to privileged users

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     proc-iomem-only-expose-physical-resource-addresses-to-privileged-users.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 51d7b120418e99d6b3bf8df9eb3cc31e8171dee4 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Thu, 14 Apr 2016 12:05:37 -0700
Subject: /proc/iomem: only expose physical resource addresses to privileged users

From: Linus Torvalds <torvalds@linux-foundation.org>

commit 51d7b120418e99d6b3bf8df9eb3cc31e8171dee4 upstream.

In commit c4004b02f8e5b ("x86: remove the kernel code/data/bss resources
from /proc/iomem") I was hoping to remove the phyiscal kernel address
data from /proc/iomem entirely, but that had to be reverted because some
system programs actually use it.

This limits all the detailed resource information to properly
credentialed users instead.

[sumits: this is used in Ubuntu as a fix for CVE-2015-8944]

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/resource.c |   13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -105,16 +105,25 @@ static int r_show(struct seq_file *m, vo
 {
 	struct resource *root = m->private;
 	struct resource *r = v, *p;
+	unsigned long long start, end;
 	int width = root->end < 0x10000 ? 4 : 8;
 	int depth;
 
 	for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
 		if (p->parent == root)
 			break;
+
+	if (file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN)) {
+		start = r->start;
+		end = r->end;
+	} else {
+		start = end = 0;
+	}
+
 	seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
 			depth * 2, "",
-			width, (unsigned long long) r->start,
-			width, (unsigned long long) r->end,
+			width, start,
+			width, end,
 			r->name ? r->name : "<BAD>");
 	return 0;
 }


Patches currently in stable-queue which might be from torvalds@linux-foundation.org are

queue-4.4/sched-cgroup-move-sched_online_group-back-into-css_online-to-fix-crash.patch
queue-4.4/proc-iomem-only-expose-physical-resource-addresses-to-privileged-users.patch
queue-4.4/drm-vmwgfx-fix-gcc-7.1.1-warning.patch
queue-4.4/isdn-i4l-fix-buffer-overflow.patch
queue-4.4/make-file-credentials-available-to-the-seqfile-interfaces.patch