diff options
Diffstat (limited to 'arch/x86/mm/dump_pagetables.c')
| -rw-r--r-- | arch/x86/mm/dump_pagetables.c | 42 |
1 files changed, 41 insertions, 1 deletions
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c index 71ab2d741024..1bf417e9cc13 100644 --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -32,6 +32,8 @@ struct pg_state { const struct addr_marker *marker; unsigned long lines; bool to_dmesg; + bool check_wx; + unsigned long wx_pages; }; struct addr_marker { @@ -214,6 +216,16 @@ static void note_page(struct seq_file *m, struct pg_state *st, 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)) { + WARN_ONCE(1, + "x86/mm: Found insecure W+X mapping at address %p/%pS\n", + (void *)st->start_address, + (void *)st->start_address); + st->wx_pages += (st->current_address - + st->start_address) / PAGE_SIZE; + } /* * Now print the actual finished series @@ -346,7 +358,8 @@ static void walk_pud_level(struct seq_file *m, struct pg_state *st, pgd_t addr, #define pgd_none(a) pud_none(__pud(pgd_val(a))) #endif -void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd) +static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd, + bool checkwx) { #ifdef CONFIG_X86_64 pgd_t *start = (pgd_t *) &init_level4_pgt; @@ -362,6 +375,10 @@ void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd) st.to_dmesg = true; } + st.check_wx = checkwx; + if (checkwx) + st.wx_pages = 0; + for (i = 0; i < PTRS_PER_PGD; i++) { st.current_address = normalize_addr(i * PGD_LEVEL_MULT); if (!pgd_none(*start)) { @@ -381,8 +398,26 @@ void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd) /* Flush out the last page */ st.current_address = normalize_addr(PTRS_PER_PGD*PGD_LEVEL_MULT); note_page(m, &st, __pgprot(0), 0); + if (!checkwx) + return; + if (st.wx_pages) + pr_info("x86/mm: Checked W+X mappings: FAILED, %lu W+X pages found.\n", + st.wx_pages); + else + pr_info("x86/mm: Checked W+X mappings: passed, no W+X pages found.\n"); +} + +void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd) +{ + ptdump_walk_pgd_level_core(m, pgd, false); } +void ptdump_walk_pgd_level_checkwx(void) +{ + ptdump_walk_pgd_level_core(NULL, NULL, true); +} + +#ifdef CONFIG_X86_PTDUMP static int ptdump_show(struct seq_file *m, void *v) { ptdump_walk_pgd_level(m, NULL); @@ -400,10 +435,13 @@ static const struct file_operations ptdump_fops = { .llseek = seq_lseek, .release = single_release, }; +#endif static int pt_dump_init(void) { +#ifdef CONFIG_X86_PTDUMP struct dentry *pe; +#endif #ifdef CONFIG_X86_32 /* Not a compile-time constant on x86-32 */ @@ -415,10 +453,12 @@ static int pt_dump_init(void) address_markers[FIXADDR_START_NR].start_address = FIXADDR_START; #endif +#ifdef CONFIG_X86_PTDUMP pe = debugfs_create_file("kernel_page_tables", 0600, NULL, NULL, &ptdump_fops); if (!pe) return -ENOMEM; +#endif return 0; } |