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| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2015-03-09 23:11:12 +0200 |
|---|---|---|
| committer | Willy Tarreau <w@1wt.eu> | 2015-05-24 10:10:53 +0200 |
| commit | 036783b2427dd1dd4f3cd0a1a9e97e511bfaac0d (patch) | |
| tree | 207fda1a5a500365e98cf1a799d91d8ab82cc918 | |
| parent | 66dff16a0d01823e04246478b86c8591b7aad447 (diff) | |
| download | lwn-036783b2427dd1dd4f3cd0a1a9e97e511bfaac0d.tar.gz lwn-036783b2427dd1dd4f3cd0a1a9e97e511bfaac0d.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>
(cherry picked from commit 1ffc3cd9a36b504c20ce98fe5eeb5463f389e1ac)
Signed-off-by: Willy Tarreau <w@1wt.eu>
| -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 3b7b82a5d13f..73db5a6e42df 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -773,9 +773,19 @@ 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 */ |