[PATCH 3.18 129/144] /proc/iomem: only expose physical resource addresses to privileged users

[Greg Kroah-Hartman]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Linus Torvalds <torva...@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.

Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Mark Salyzyn <saly...@android.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 kernel/resource.c |   13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -104,16 +104,25 @@ 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;
 }