x86/mm/pae: Populate the user page-table with user pgd's

CVE-2017-5754

When a PGD entry is populated, make sure to populate it in the user
page-table too.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Pavel Machek <pavel@ucw.cz>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.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: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Cc: joro@8bytes.org
Link: https://lkml.kernel.org/r/1531906876-13451-23-git-send-email-joro@8bytes.org
(cherry picked from commit 9b7b8bbd7f6ba4ef7caa5a078ead70237e12d045)
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/arch/x86/include/asm/pgtable-3level.h b/arch/x86/include/asm/pgtable-3level.h
index 9dc19b4a2a870398e57239c9af545924713b0b49..a18fa4eac97bb64bb6c4ae86f380809d5395b908 100644 (file)
--- a/arch/x86/include/asm/pgtable-3level.h
+++ b/arch/x86/include/asm/pgtable-3level.h
@@ -98,6 +98,9 @@ static inline void native_set_pmd(pmd_t *pmdp, pmd_t pmd)
 
 static inline void native_set_pud(pud_t *pudp, pud_t pud)
 {
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
+       pud.p4d.pgd = pti_set_user_pgtbl(&pudp->p4d.pgd, pud.p4d.pgd);
+#endif
        set_64bit((unsigned long long *)(pudp), native_pud_val(pud));
 }
 
@@ -194,6 +197,10 @@ static inline pud_t native_pudp_get_and_clear(pud_t *pudp)
 {
        union split_pud res, *orig = (union split_pud *)pudp;
 
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
+       pti_set_user_pgtbl(&pudp->p4d.pgd, __pgd(0));
+#endif
+
        /* xchg acts as a barrier before setting of the high bits */
        res.pud_low = xchg(&orig->pud_low, 0);
        res.pud_high = orig->pud_high;