From: Borislav Petkov <bp@suse.de>
Date: Mon, 4 Dec 2017 15:08:04 +0100
Subject: x86/mm/dump_pagetables: Add page table directory to the debugfs VFS
hierarchy
Git-commit: 75298aa179d56cd64f54e58a19fffc8ab922b4c0
Patch-mainline: v4.15-rc6
References: bsc#1068032 CVE-2017-5754
The upcoming support for dumping the kernel and the user space page tables
of the current process would create more random files in the top level
debugfs directory.
Add a page table directory and move the existing file to it.
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/mm/debug_pagetables.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/arch/x86/mm/debug_pagetables.c b/arch/x86/mm/debug_pagetables.c
index bfcffdf6c577..d1449fb6dc7a 100644
--- a/arch/x86/mm/debug_pagetables.c
+++ b/arch/x86/mm/debug_pagetables.c
@@ -22,21 +22,26 @@ static const struct file_operations ptdump_fops = {
.release = single_release,
};
-static struct dentry *pe;
+static struct dentry *dir, *pe;
static int __init pt_dump_debug_init(void)
{
- pe = debugfs_create_file("kernel_page_tables", S_IRUSR, NULL, NULL,
- &ptdump_fops);
- if (!pe)
+ dir = debugfs_create_dir("page_tables", NULL);
+ if (!dir)
return -ENOMEM;
+ pe = debugfs_create_file("kernel", 0400, dir, NULL, &ptdump_fops);
+ if (!pe)
+ goto err;
return 0;
+err:
+ debugfs_remove_recursive(dir);
+ return -ENOMEM;
}
static void __exit pt_dump_debug_exit(void)
{
- debugfs_remove_recursive(pe);
+ debugfs_remove_recursive(dir);
}
module_init(pt_dump_debug_init);