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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2015-03-09 23:11:12 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-04-19 10:10:51 +0200
commite11b708502b0e249772e485585bec44be5fe8c70 (patch)
tree8b6ccdcb7009f6db5f0312bfe60ff3d21f440949 /fs
parent391f1c610abe2db94c3e5c7ae20528ebf9ed682f (diff)
downloadlinux-linaro-stable-e11b708502b0e249772e485585bec44be5fe8c70.tar.gz
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>
Diffstat (limited to 'fs')
-rw-r--r--fs/proc/task_mmu.c10
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 */