From: Joerg Roedel <jroedel@xxxxxxx>
The user page-table gets the updated kernel mappings in
pti_finalize(), which runs after the RO+X permissions got
applied to the kernel page-table in mark_readonly().
But with CONFIG_DEBUG_WX enabled, the user page-table is
already checked in mark_readonly() for insecure mappings.
This causes false-positive warnings, because the user
page-table did not get the updated mappings yet.
Move the W+X check for the user page-table into
pti_finalize() after it updated all required mappings.
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
---
arch/x86/include/asm/pgtable.h | 7 +++++--
arch/x86/mm/dump_pagetables.c | 3 +--
arch/x86/mm/pti.c | 2 ++
3 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index e39088cb..a1cb333 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -30,11 +30,14 @@ int __init __early_make_pgtable(unsigned long address, pmdval_t pmd);
void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd);
void ptdump_walk_pgd_level_debugfs(struct seq_file *m, pgd_t *pgd, bool user);
void ptdump_walk_pgd_level_checkwx(void);
+void ptdump_walk_user_pgd_level_checkwx(void);
#ifdef CONFIG_DEBUG_WX
-#define debug_checkwx() ptdump_walk_pgd_level_checkwx()
+#define debug_checkwx() ptdump_walk_pgd_level_checkwx()
+#define debug_checkwx_user() ptdump_walk_user_pgd_level_checkwx()
#else
-#define debug_checkwx() do { } while (0)
+#define debug_checkwx() do { } while (0)
+#define debug_checkwx_user() do { } while (0)
#endif
/*
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index ccd92c4..b8ab901 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -569,7 +569,7 @@ void ptdump_walk_pgd_level_debugfs(struct seq_file *m, pgd_t *pgd, bool user)
}
EXPORT_SYMBOL_GPL(ptdump_walk_pgd_level_debugfs);
-static void ptdump_walk_user_pgd_level_checkwx(void)
+void ptdump_walk_user_pgd_level_checkwx(void)
{
#ifdef CONFIG_PAGE_TABLE_ISOLATION
pgd_t *pgd = INIT_PGD;
@@ -586,7 +586,6 @@ static void ptdump_walk_user_pgd_level_checkwx(void)
void ptdump_walk_pgd_level_checkwx(void)
{
ptdump_walk_pgd_level_core(NULL, NULL, true, false);
- ptdump_walk_user_pgd_level_checkwx();
}
static int __init pt_dump_init(void)
diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
index 69a9d60..026a89a 100644
--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -628,4 +628,6 @@ void pti_finalize(void)
*/
pti_clone_entry_text();
pti_clone_kernel_text();
+
+ debug_checkwx_user();
}
--
2.7.4
