x86/misc: CFI hardening

Control Flow Integrity schemes use toolchain and optionally hardware support
to help protect against call/jump/return oriented programming attacks.

Use cf_check to annotate function pointer targets for the toolchain.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

diff --git a/xen/arch/x86/extable.c b/xen/arch/x86/extable.c
index 51ef863d786c8fa1386084357b0d80b29179aefc..4d1875585f9d997bbdd76e9bbb8408146895f9bb 100644 (file)
--- a/xen/arch/x86/extable.c
+++ b/xen/arch/x86/extable.c
@@ -23,7 +23,7 @@ static inline unsigned long ex_cont(const struct exception_table_entry *x)
        return EX_FIELD(x, cont);
 }
 
-static int init_or_livepatch cmp_ex(const void *a, const void *b)
+static int init_or_livepatch cf_check cmp_ex(const void *a, const void *b)
 {
        const struct exception_table_entry *l = a, *r = b;
        unsigned long lip = ex_addr(l);
@@ -37,7 +37,7 @@ static int init_or_livepatch cmp_ex(const void *a, const void *b)
        return 0;
 }
 
-static void init_or_livepatch swap_ex(void *a, void *b, size_t size)
+static void init_or_livepatch cf_check swap_ex(void *a, void *b, size_t size)
 {
        struct exception_table_entry *l = a, *r = b, tmp;
        long delta = b - a;

diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
index f31f68fd4cd1ad874ca6a8487d4b10c34e101146..4dd5ea6a060257f8c7bf573ae46277a3f23e2be2 100644 (file)
--- a/xen/common/efi/boot.c
+++ b/xen/common/efi/boot.c
@@ -1497,7 +1497,7 @@ static __init void copy_mapping(unsigned long mfn, unsigned long end,
     unmap_domain_page(l3dst);
 }
 
-static bool __init ram_range_valid(unsigned long smfn, unsigned long emfn)
+static bool __init cf_check ram_range_valid(unsigned long smfn, unsigned long emfn)
 {
     unsigned long sz = pfn_to_pdx(emfn - 1) / PDX_GROUP_COUNT + 1;
 
@@ -1506,7 +1506,7 @@ static bool __init ram_range_valid(unsigned long smfn, unsigned long emfn)
                          pfn_to_pdx(smfn) / PDX_GROUP_COUNT) < sz;
 }
 
-static bool __init rt_range_valid(unsigned long smfn, unsigned long emfn)
+static bool __init cf_check rt_range_valid(unsigned long smfn, unsigned long emfn)
 {
     return true;
 }