Messages in this thread | | | Date | Mon, 15 Oct 2018 21:27:53 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH] arm64: kprobe: make page to RO mode when allocate it |
| |
On Mon, 15 Oct 2018 13:22:12 +0200 Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> (+ Masami) > > On 15 October 2018 at 13:16, Anders Roxell <anders.roxell@linaro.org> wrote: > > Commit 1404d6f13e47 ("arm64: dump: Add checking for writable and exectuable pages") > > has successfully identified code that leaves a page with W+X > > permissions. > > > > [ 3.245140] arm64/mm: Found insecure W+X mapping at address (____ptrval____)/0xffff000000d90000 > > [ 3.245771] WARNING: CPU: 0 PID: 1 at ../arch/arm64/mm/dump.c:232 note_page+0x410/0x420 > > [ 3.246141] Modules linked in: > > [ 3.246653] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc5-next-20180928-00001-ge70ae259b853-dirty #62 > > [ 3.247008] Hardware name: linux,dummy-virt (DT) > > [ 3.247347] pstate: 80000005 (Nzcv daif -PAN -UAO) > > [ 3.247623] pc : note_page+0x410/0x420 > > [ 3.247898] lr : note_page+0x410/0x420 > > [ 3.248071] sp : ffff00000804bcd0 > > [ 3.248254] x29: ffff00000804bcd0 x28: ffff000009274000 > > [ 3.248578] x27: ffff00000921a000 x26: ffff80007dfff000 > > [ 3.248845] x25: ffff0000093f5000 x24: ffff000009526f6a > > [ 3.249109] x23: 0000000000000004 x22: ffff000000d91000 > > [ 3.249396] x21: ffff000000d90000 x20: 0000000000000000 > > [ 3.249661] x19: ffff00000804bde8 x18: 0000000000000400 > > [ 3.249924] x17: 0000000000000000 x16: 0000000000000000 > > [ 3.250271] x15: ffffffffffffffff x14: 295f5f5f5f6c6176 > > [ 3.250594] x13: 7274705f5f5f5f28 x12: 2073736572646461 > > [ 3.250941] x11: 20746120676e6970 x10: 70616d20582b5720 > > [ 3.251252] x9 : 6572756365736e69 x8 : 3039643030303030 > > [ 3.251519] x7 : 306666666678302f x6 : ffff0000095467b2 > > [ 3.251802] x5 : 0000000000000000 x4 : 0000000000000000 > > [ 3.252060] x3 : 0000000000000000 x2 : ffffffffffffffff > > [ 3.252323] x1 : 4d151327adc50b00 x0 : 0000000000000000 > > [ 3.252664] Call trace: > > [ 3.252953] note_page+0x410/0x420 > > [ 3.253186] walk_pgd+0x12c/0x238 > > [ 3.253417] ptdump_check_wx+0x68/0xf8 > > [ 3.253637] mark_rodata_ro+0x68/0x98 > > [ 3.253847] kernel_init+0x38/0x160 > > [ 3.254103] ret_from_fork+0x10/0x18 > > > > Reworked to that when allocate a page it sets mode RO. Inspired by > > commit 63fef14fc98a ("kprobes/x86: Make insn buffer always ROX and use text_poke()").
Yeah, that looks similar issue on x86, and looks good to me. Thank you for fixing it!
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
> > > > Cc: Arnd Bergmann <arnd@arndb.de> > > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> > > Cc: Laura Abbott <labbott@redhat.com> > > Cc: Catalin Marinas <catalin.marinas@arm.com> > > Co-developed-by: Arnd Bergmann <arnd@arndb.de> > > Co-developed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > > Signed-off-by: Anders Roxell <anders.roxell@linaro.org> > > --- > > arch/arm64/kernel/probes/kprobes.c | 27 ++++++++++++++++++++------- > > 1 file changed, 20 insertions(+), 7 deletions(-) > > > > diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c > > index 9b65132e789a..b842e908b423 100644 > > --- a/arch/arm64/kernel/probes/kprobes.c > > +++ b/arch/arm64/kernel/probes/kprobes.c > > @@ -23,7 +23,9 @@ > > #include <linux/slab.h> > > #include <linux/stop_machine.h> > > #include <linux/sched/debug.h> > > +#include <linux/set_memory.h> > > #include <linux/stringify.h> > > +#include <linux/vmalloc.h> > > #include <asm/traps.h> > > #include <asm/ptrace.h> > > #include <asm/cacheflush.h> > > @@ -42,10 +44,21 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); > > static void __kprobes > > post_kprobe_handler(struct kprobe_ctlblk *, struct pt_regs *); > > > > +static int __kprobes patch_text(kprobe_opcode_t *addr, u32 opcode) > > +{ > > + void *addrs[1]; > > + u32 insns[1]; > > + > > + addrs[0] = (void *)addr; > > + insns[0] = (u32)opcode; > > + > > + return aarch64_insn_patch_text(addrs, insns, 1); > > +} > > + > > static void __kprobes arch_prepare_ss_slot(struct kprobe *p) > > { > > /* prepare insn slot */ > > - p->ainsn.api.insn[0] = cpu_to_le32(p->opcode); > > + patch_text(p->ainsn.api.insn, p->opcode); > > > > flush_icache_range((uintptr_t) (p->ainsn.api.insn), > > (uintptr_t) (p->ainsn.api.insn) + > > @@ -118,15 +131,15 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) > > return 0; > > } > > > > -static int __kprobes patch_text(kprobe_opcode_t *addr, u32 opcode) > > +void *alloc_insn_page(void) > > { > > - void *addrs[1]; > > - u32 insns[1]; > > + void *page; > > > > - addrs[0] = (void *)addr; > > - insns[0] = (u32)opcode; > > + page = vmalloc_exec(PAGE_SIZE); > > + if (page) > > + set_memory_ro((unsigned long)page & PAGE_MASK, 1); > > > > - return aarch64_insn_patch_text(addrs, insns, 1); > > + return page; > > } > > > > /* arm kprobe: install breakpoint in text */ > > -- > > 2.19.1 > >
-- Masami Hiramatsu <mhiramat@kernel.org>
| |