On 02/26/2018 11:48 AM, tip-bot for Jan Beulich wrote:
> static void note_page(struct seq_file *m, struct pg_state *st,
> - pgprot_t new_prot, int level)
> + pgprot_t new_prot, pgprotval_t new_eff, int level)
> {
> - pgprotval_t prot, cur;
> + pgprotval_t prot, cur, eff;
> static const char units[] = "BKMGTPE";
>
> /*
> @@ -247,23 +248,24 @@ static void note_page(struct seq_file *m, struct
> pg_state *st,
> */
> prot = pgprot_val(new_prot);
> cur = pgprot_val(st->current_prot);
> + eff = st->effective_prot;
>
> if (!st->level) {
> /* First entry */
> st->current_prot = new_prot;
> + st->effective_prot = new_eff;
> st->level = level;
> st->marker = address_markers;
> st->lines = 0;
> pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",
> st->marker->name);
> - } else if (prot != cur || level != st->level ||
> + } else if (prot != cur || new_eff != eff || level != st->level ||
> st->current_address >= st->marker[1].start_address) {
> const char *unit = units;
> unsigned long delta;
> int width = sizeof(unsigned long) * 2;
> - pgprotval_t pr = pgprot_val(st->current_prot);
>
> - if (st->check_wx && (pr & _PAGE_RW) && !(pr & _PAGE_NX)) {
> + if (st->check_wx && (eff & _PAGE_RW) && !(eff & _PAGE_NX)) {
> WARN_ONCE(1,
> "x86/mm: Found insecure W+X mapping at
> address %p/%pS\n",
> (void *)st->start_address,
> @@ -317,21 +319,30 @@ static void note_page(struct seq_file *m, struct
> pg_state *st,
>
> st->start_address = st->current_address;
> st->current_prot = new_prot;
> + st->effective_prot = new_eff;
> st->level = level;
> }
> }
>
> -static void walk_pte_level(struct seq_file *m, struct pg_state *st, pmd_t
> addr, unsigned long P)
> +static inline pgprotval_t effective_prot(pgprotval_t prot1, pgprotval_t
> prot2)
> +{
> + return (prot1 & prot2 & (_PAGE_USER | _PAGE_RW)) |
> + ((prot1 | prot2) & _PAGE_NX);
> +}
> +
> +static void walk_pte_level(struct seq_file *m, struct pg_state *st, pmd_t
> addr,
> + pgprotval_t eff_in, unsigned long P)
> {
> int i;
> pte_t *start;
> - pgprotval_t prot;
> + pgprotval_t prot, eff;
>
> start = (pte_t *)pmd_page_vaddr(addr);
> for (i = 0; i < PTRS_PER_PTE; i++) {
> prot = pte_flags(*start);
> + eff = effective_prot(eff_in, prot);
> st->current_address = normalize_addr(P + i * PTE_LEVEL_MULT);
> - note_page(m, st, __pgprot(prot), 5);
> + note_page(m, st, __pgprot(prot), eff, 5);
> start++;
> }
> }
> @@ -351,7 +362,7 @@ static inline bool kasan_page_table(struct seq_file *m,
> struct pg_state *st,
> (pgtable_l5_enabled && __pa(pt) == __pa(kasan_zero_p4d)) ||
> __pa(pt) == __pa(kasan_zero_pud)) {
> pgprotval_t prot = pte_flags(kasan_zero_pte[0]);
> - note_page(m, st, __pgprot(prot), 5);
> + note_page(m, st, __pgprot(prot), 0, 5);
Isn't this disables W+X check for kasan page table?
Methinks it should be 'prot' here.
