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| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2015-03-09 23:11:12 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-04-19 10:10:51 +0200 |
| commit | e11b708502b0e249772e485585bec44be5fe8c70 (patch) | |
| tree | 8b6ccdcb7009f6db5f0312bfe60ff3d21f440949 | |
| parent | 391f1c610abe2db94c3e5c7ae20528ebf9ed682f (diff) | |
| download | lwn-e11b708502b0e249772e485585bec44be5fe8c70.tar.gz lwn-e11b708502b0e249772e485585bec44be5fe8c70.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>
Signed-off-by: mancha security <mancha1@zoho.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 65fc60a07c47..9f285fb9bab3 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1110,9 +1110,19 @@ 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 */ |