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Message-Id: <20170804231558.373276312@linuxfoundation.org>
Date: Fri, 4 Aug 2017 16:15:39 -0700
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org,
Linus Torvalds <torvalds@...ux-foundation.org>,
Sumit Semwal <sumit.semwal@...aro.org>
Subject: [PATCH 4.4 43/91] /proc/iomem: only expose physical resource addresses to privileged users
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Linus Torvalds <torvalds@...ux-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@...ux-foundation.org>
Signed-off-by: Sumit Semwal <sumit.semwal@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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;
}
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