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| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2015-03-09 23:11:12 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2015-05-09 23:16:30 +0100 |
| commit | 1ffc3cd9a36b504c20ce98fe5eeb5463f389e1ac (patch) | |
| tree | c2e6f5095edfea84adbf431ea64abedd9527f90d /fs | |
| parent | fd78d926566a189d7c12c1e1bf79851b7ff7a669 (diff) | |
| download | lwn-1ffc3cd9a36b504c20ce98fe5eeb5463f389e1ac.tar.gz lwn-1ffc3cd9a36b504c20ce98fe5eeb5463f389e1ac.zip | |
pagemap: do not leak physical addresses to non-privileged userspace
commit ab676b7d6fbf4b294bf198fb27ade5b0e865c7ce upstream.
As pointed by recent post[1] on exploiting DRAM physical imperfection,
/proc/PID/pagemap exposes sensitive information which can be used to do
attacks.
This disallows anybody without CAP_SYS_ADMIN to read the pagemap.
[1] http://googleprojectzero.blogspot.com/2015/03/exploiting-dram-rowhammer-bug-to-gain.html
[ Eventually we might want to do anything more finegrained, but for now
this is the simple model. - Linus ]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mark Seaborn <mseaborn@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[mancha security: Backported to 3.10]
Signed-off-by: mancha security <mancha1@zoho.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/proc/task_mmu.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index ef1740d07c31..d1bd6a9d15f8 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -864,9 +864,19 @@ 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 */ |