From: "Kirill A. Shutemov" <kirill.shute...@linux.intel.com>
3.4.107-rc1 review patch. If anyone has any objections, please let me know. ------------------ 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.shute...@linux.intel.com> Acked-by: Konstantin Khlebnikov <khlebni...@openvz.org> Acked-by: Andy Lutomirski <l...@amacapital.net> Cc: Pavel Emelyanov <xe...@parallels.com> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Mark Seaborn <mseab...@chromium.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Zefan Li <lize...@huawei.com> [mancha: Backported to 3.10] Signed-off-by: mancha security <manc...@zoho.com> --- fs/proc/task_mmu.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 8df7fd2..bc17933 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -985,9 +985,19 @@ 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 */ -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
