Hi Edward, On Fri, Sep 29, 2023 at 1:12 AM Edward AD <twuufnxlz@xxxxxxxxx> wrote: > > Add vmalloc and kernel addresses check to prevent invalid access. > > Closes: https://lore.kernel.org/all/20230926105949.1025995-2-twuufnxlz@xxxxxxxxx/ > Fixes: 5d8544e2d007 ("RISC-V: Generic library routines and assembly") > Reported-and-test-by: syzbot+8d2757d62d403b2d9275@xxxxxxxxxxxxxxxxxxxxxxxxx > Link: https://lore.kernel.org/all/0000000000000170df0605ccf91a@xxxxxxxxxx/T/ > Signed-off-by: Edward AD <twuufnxlz@xxxxxxxxx> > --- > arch/riscv/kernel/stacktrace.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c > index 64a9c093aef9..031a4a35c1d0 100644 > --- a/arch/riscv/kernel/stacktrace.c > +++ b/arch/riscv/kernel/stacktrace.c > @@ -54,6 +54,9 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs, > break; > /* Unwind stack frame */ > frame = (struct stackframe *)fp - 1; > + if ((is_vmalloc_addr(frame) && !pfn_valid(page_to_pfn(vmalloc_to_page(frame)))) || > + !virt_addr_valid(frame)) > + break; > sp = fp; > if (regs && (regs->epc == pc) && (frame->fp & 0x7)) { > fp = frame->ra; > -- > 2.25.1 > I'm still not convinced this will fix the kasan out-of-bounds accesses, the page can be valid but the read can happen at an offset not initialized and trigger such errors right? I still think there is something weird about the stack frame, as to me this should not happen (but admittedly I don't know much about that).
