[RFC PATCH v3 11/15] mm: Map page tables with privileged pkey
From: Kevin Brodsky <hidden>
Date: 2025-02-03 10:20:24
Also in:
linux-hardening, linux-mm, lkml
Subsystem:
memory management - core, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
If CONFIG_KPKEYS_HARDENED_PGTABLES is enabled, map allocated page table pages using a privileged pkey (KPKEYS_PKEY_PGTABLES), so that page tables can only be written under guard(kpkeys_hardened_pgtables). This patch is a no-op if CONFIG_KPKEYS_HARDENED_PGTABLES is disabled (default). Signed-off-by: Kevin Brodsky <redacted> --- include/linux/mm.h | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 721e779647f3..aa01f51fdc6f 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h@@ -32,6 +32,7 @@ #include <linux/memremap.h> #include <linux/slab.h> #include <linux/cacheinfo.h> +#include <linux/kpkeys.h> struct mempolicy; struct anon_vma;
@@ -2998,6 +2999,8 @@ static inline bool __pagetable_ctor(struct ptdesc *ptdesc) __folio_set_pgtable(folio); lruvec_stat_add_folio(folio, NR_PAGETABLE); + if (kpkeys_protect_pgtable_memory(folio)) + return false; return true; }
@@ -3008,6 +3011,7 @@ static inline void pagetable_dtor(struct ptdesc *ptdesc) ptlock_free(ptdesc); __folio_clear_pgtable(folio); lruvec_stat_sub_folio(folio, NR_PAGETABLE); + kpkeys_unprotect_pgtable_memory(folio); } static inline void pagetable_dtor_free(struct ptdesc *ptdesc)
--
2.47.0