diff options
Diffstat (limited to 'arch/arm64/mm/dump.c')
-rw-r--r-- | arch/arm64/mm/dump.c | 106 |
1 files changed, 78 insertions, 28 deletions
diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c index 9c3e75df2180..ca74a2aace42 100644 --- a/arch/arm64/mm/dump.c +++ b/arch/arm64/mm/dump.c @@ -50,6 +50,18 @@ static const struct addr_marker address_markers[] = { { -1, NULL }, }; +#define pt_dump_seq_printf(m, fmt, args...) \ +({ \ + if (m) \ + seq_printf(m, fmt, ##args); \ +}) + +#define pt_dump_seq_puts(m, fmt) \ +({ \ + if (m) \ + seq_printf(m, fmt); \ +}) + /* * The page dumper groups page table entries of the same type into a single * description. It uses pg_state to track the range information while @@ -62,6 +74,9 @@ struct pg_state { unsigned long start_address; unsigned level; u64 current_prot; + bool check_wx; + unsigned long wx_pages; + unsigned long uxn_pages; }; struct prot_bits { @@ -186,10 +201,39 @@ static void dump_prot(struct pg_state *st, const struct prot_bits *bits, s = bits->clear; if (s) - seq_printf(st->seq, " %s", s); + pt_dump_seq_printf(st->seq, " %s", s); } } +static void note_prot_uxn(struct pg_state *st, unsigned long addr) +{ + if (!st->check_wx) + return; + + if ((st->current_prot & PTE_UXN) == PTE_UXN) + return; + + WARN_ONCE(1, "arm64/mm: Found non-UXN mapping at address %p/%pS\n", + (void *)st->start_address, (void *)st->start_address); + + st->uxn_pages += (addr - st->start_address) / PAGE_SIZE; +} + +static void note_prot_wx(struct pg_state *st, unsigned long addr) +{ + if (!st->check_wx) + return; + if ((st->current_prot & PTE_RDONLY) == PTE_RDONLY) + return; + if ((st->current_prot & PTE_PXN) == PTE_PXN) + return; + + WARN_ONCE(1, "arm64/mm: Found insecure W+X mapping at address %p/%pS\n", + (void *)st->start_address, (void *)st->start_address); + + st->wx_pages += (addr - st->start_address) / PAGE_SIZE; +} + static void note_page(struct pg_state *st, unsigned long addr, unsigned level, u64 val) { @@ -200,14 +244,16 @@ static void note_page(struct pg_state *st, unsigned long addr, unsigned level, st->level = level; st->current_prot = prot; st->start_address = addr; - seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); + pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); } else if (prot != st->current_prot || level != st->level || addr >= st->marker[1].start_address) { const char *unit = units; unsigned long delta; if (st->current_prot) { - seq_printf(st->seq, "0x%016lx-0x%016lx ", + note_prot_uxn(st, addr); + note_prot_wx(st, addr); + pt_dump_seq_printf(st->seq, "0x%016lx-0x%016lx ", st->start_address, addr); delta = (addr - st->start_address) >> 10; @@ -215,17 +261,17 @@ static void note_page(struct pg_state *st, unsigned long addr, unsigned level, delta >>= 10; unit++; } - seq_printf(st->seq, "%9lu%c %s", delta, *unit, + pt_dump_seq_printf(st->seq, "%9lu%c %s", delta, *unit, pg_level[st->level].name); if (pg_level[st->level].bits) dump_prot(st, pg_level[st->level].bits, pg_level[st->level].num); - seq_puts(st->seq, "\n"); + pt_dump_seq_puts(st->seq, "\n"); } if (addr >= st->marker[1].start_address) { st->marker++; - seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); + pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); } st->start_address = addr; @@ -235,7 +281,7 @@ static void note_page(struct pg_state *st, unsigned long addr, unsigned level, if (addr >= st->marker[1].start_address) { st->marker++; - seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); + pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); } } @@ -304,9 +350,8 @@ static void walk_pgd(struct pg_state *st, struct mm_struct *mm, } } -static int ptdump_show(struct seq_file *m, void *v) +void ptdump_walk_pgd(struct seq_file *m, struct ptdump_info *info) { - struct ptdump_info *info = m->private; struct pg_state st = { .seq = m, .marker = info->markers, @@ -315,33 +360,16 @@ static int ptdump_show(struct seq_file *m, void *v) walk_pgd(&st, info->mm, info->base_addr); note_page(&st, 0, 0, 0); - return 0; } -static int ptdump_open(struct inode *inode, struct file *file) +static void ptdump_initialize(void) { - return single_open(file, ptdump_show, inode->i_private); -} - -static const struct file_operations ptdump_fops = { - .open = ptdump_open, - .read = seq_read, - .llseek = seq_lseek, - .release = single_release, -}; - -int ptdump_register(struct ptdump_info *info, const char *name) -{ - struct dentry *pe; unsigned i, j; for (i = 0; i < ARRAY_SIZE(pg_level); i++) if (pg_level[i].bits) for (j = 0; j < pg_level[i].num; j++) pg_level[i].mask |= pg_level[i].bits[j].mask; - - pe = debugfs_create_file(name, 0400, NULL, info, &ptdump_fops); - return pe ? 0 : -ENOMEM; } static struct ptdump_info kernel_ptdump_info = { @@ -350,8 +378,30 @@ static struct ptdump_info kernel_ptdump_info = { .base_addr = VA_START, }; +void ptdump_check_wx(void) +{ + struct pg_state st = { + .seq = NULL, + .marker = (struct addr_marker[]) { + { 0, NULL}, + { -1, NULL}, + }, + .check_wx = true, + }; + + walk_pgd(&st, &init_mm, 0); + note_page(&st, 0, 0, 0); + if (st.wx_pages || st.uxn_pages) + pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found, %lu non-UXN pages found\n", + st.wx_pages, st.uxn_pages); + else + pr_info("Checked W+X mappings: passed, no W+X pages found\n"); +} + static int ptdump_init(void) { - return ptdump_register(&kernel_ptdump_info, "kernel_page_tables"); + ptdump_initialize(); + return ptdump_debugfs_register(&kernel_ptdump_info, + "kernel_page_tables"); } device_initcall(ptdump_init); |