Straightforward, except for save_altstack_ex() stuck in those. Replace that thing with an analogue that would use unsafe_put_user() instead of put_user_ex() (called compat_save_altstack()) and be done with that.
Unified · Split
| @@ -365,38 +365,37 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig, · 364 unmodified lines | ||
| 365 | 365 | |
| 366 | 366 | frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); |
| 367 | 367 | |
| 368 | − if (!access_ok(frame, sizeof(*frame))) | |
| 368 | + if (!user_access_begin(frame, sizeof(*frame))) | |
| 369 | 369 | return -EFAULT; |
| 370 | 370 | |
| 371 | − put_user_try { | |
| 372 | − put_user_ex(sig, &frame->sig); | |
| 373 | − put_user_ex(&frame->info, &frame->pinfo); | |
| 374 | − put_user_ex(&frame->uc, &frame->puc); | |
| 371 | + unsafe_put_user(sig, &frame->sig, Efault); | |
| 372 | + unsafe_put_user(&frame->info, &frame->pinfo, Efault); | |
| 373 | + unsafe_put_user(&frame->uc, &frame->puc, Efault); | |
| 375 | 374 | |
| 376 | − /* Create the ucontext. */ | |
| 377 | − if (static_cpu_has(X86_FEATURE_XSAVE)) | |
| 378 | − put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); | |
| 379 | − else | |
| 380 | − put_user_ex(0, &frame->uc.uc_flags); | |
| 381 | − put_user_ex(0, &frame->uc.uc_link); | |
| 382 | − save_altstack_ex(&frame->uc.uc_stack, regs->sp); | |
| 375 | + /* Create the ucontext. */ | |
| 376 | + if (static_cpu_has(X86_FEATURE_XSAVE)) | |
| 377 | + unsafe_put_user(UC_FP_XSTATE, &frame->uc.uc_flags, Efault); | |
| 378 | + else | |
| 379 | + unsafe_put_user(0, &frame->uc.uc_flags, Efault); | |
| 380 | + unsafe_put_user(0, &frame->uc.uc_link, Efault); | |
| 381 | + unsafe_save_altstack(&frame->uc.uc_stack, regs->sp, Efault); | |
| 383 | 382 | |
| 384 | − /* Set up to return from userspace. */ | |
| 385 | − restorer = current->mm->context.vdso + | |
| 386 | − vdso_image_32.sym___kernel_rt_sigreturn; | |
| 387 | − if (ksig->ka.sa.sa_flags & SA_RESTORER) | |
| 388 | − restorer = ksig->ka.sa.sa_restorer; | |
| 389 | − put_user_ex(restorer, &frame->pretcode); | |
| 383 | + /* Set up to return from userspace. */ | |
| 384 | + restorer = current->mm->context.vdso + | |
| 385 | + vdso_image_32.sym___kernel_rt_sigreturn; | |
| 386 | + if (ksig->ka.sa.sa_flags & SA_RESTORER) | |
| 387 | + restorer = ksig->ka.sa.sa_restorer; | |
| 388 | + unsafe_put_user(restorer, &frame->pretcode, Efault); | |
| 390 | 389 | |
| 391 | − /* | |
| 392 | − * This is movl $__NR_rt_sigreturn, %ax ; int $0x80 | |
| 393 | − * | |
| 394 | − * WE DO NOT USE IT ANY MORE! It's only left here for historical | |
| 395 | − * reasons and because gdb uses it as a signature to notice | |
| 396 | − * signal handler stack frames. | |
| 397 | − */ | |
| 398 | − put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode); | |
| 399 | − } put_user_catch(err); | |
| 390 | + /* | |
| 391 | + * This is movl $__NR_rt_sigreturn, %ax ; int $0x80 | |
| 392 | + * | |
| 393 | + * WE DO NOT USE IT ANY MORE! It's only left here for historical | |
| 394 | + * reasons and because gdb uses it as a signature to notice | |
| 395 | + * signal handler stack frames. | |
| 396 | + */ | |
| 397 | + unsafe_put_user(*((u64 *)&rt_retcode), (u64 *)frame->retcode, Efault); | |
| 398 | + user_access_end(); | |
| 400 | 399 | |
| 401 | 400 | err |= copy_siginfo_to_user(&frame->info, &ksig->info); |
| 402 | 401 | err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate, |
| @@ -419,6 +418,9 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig, · 16 unmodified lines | ||
| 419 | 418 | regs->cs = __USER_CS; |
| 420 | 419 | |
| 421 | 420 | return 0; |
| 421 | +Efault: | |
| 422 | + user_access_end(); | |
| 423 | + return -EFAULT; | |
| 422 | 424 | } |
| 423 | 425 | #else /* !CONFIG_X86_32 */ |
| 424 | 426 | static unsigned long frame_uc_flags(struct pt_regs *regs) |
| @@ -444,6 +446,10 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig, · 19 unmodified lines | ||
| 444 | 446 | unsigned long uc_flags; |
| 445 | 447 | int err = 0; |
| 446 | 448 | |
| 449 | + /* x86-64 should always use SA_RESTORER. */ | |
| 450 | + if (!(ksig->ka.sa.sa_flags & SA_RESTORER)) | |
| 451 | + return -EFAULT; | |
| 452 | + | |
| 447 | 453 | frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp); |
| 448 | 454 | |
| 449 | 455 | if (!access_ok(frame, sizeof(*frame))) |
| @@ -455,23 +461,18 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig, · 5 unmodified lines | ||
| 455 | 461 | } |
| 456 | 462 | |
| 457 | 463 | uc_flags = frame_uc_flags(regs); |
| 464 | + if (!user_access_begin(frame, sizeof(*frame))) | |
| 465 | + return -EFAULT; | |
| 458 | 466 | |
| 459 | − put_user_try { | |
| 460 | − /* Create the ucontext. */ | |
| 461 | − put_user_ex(uc_flags, &frame->uc.uc_flags); | |
| 462 | − put_user_ex(0, &frame->uc.uc_link); | |
| 463 | − save_altstack_ex(&frame->uc.uc_stack, regs->sp); | |
| 464 | − | |
| 465 | − /* Set up to return from userspace. If provided, use a stub | |
| 466 | − already in userspace. */ | |
| 467 | − /* x86-64 should always use SA_RESTORER. */ | |
| 468 | − if (ksig->ka.sa.sa_flags & SA_RESTORER) { | |
| 469 | − put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode); | |
| 470 | − } else { | |
| 471 | − /* could use a vstub here */ | |
| 472 | − err |= -EFAULT; | |
| 473 | − } | |
| 474 | − } put_user_catch(err); | |
| 467 | + /* Create the ucontext. */ | |
| 468 | + unsafe_put_user(uc_flags, &frame->uc.uc_flags, Efault); | |
| 469 | + unsafe_put_user(0, &frame->uc.uc_link, Efault); | |
| 470 | + unsafe_save_altstack(&frame->uc.uc_stack, regs->sp, Efault); | |
| 471 | + | |
| 472 | + /* Set up to return from userspace. If provided, use a stub | |
| 473 | + already in userspace. */ | |
| 474 | + unsafe_put_user(ksig->ka.sa.sa_restorer, &frame->pretcode, Efault); | |
| 475 | + user_access_end(); | |
| 475 | 476 | |
| 476 | 477 | err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]); |
| 477 | 478 | err |= __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]); |
| @@ -515,6 +516,10 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig, · 37 unmodified lines | ||
| 515 | 516 | force_valid_ss(regs); |
| 516 | 517 | |
| 517 | 518 | return 0; |
| 519 | + | |
| 520 | +Efault: | |
| 521 | + user_access_end(); | |
| 522 | + return -EFAULT; | |
| 518 | 523 | } |
| 519 | 524 | #endif /* CONFIG_X86_32 */ |
| 520 | 525 | |
| @@ -444,12 +444,12 @@ void signals_init(void); · 443 unmodified lines | ||
| 444 | 444 | int restore_altstack(const stack_t __user *); |
| 445 | 445 | int __save_altstack(stack_t __user *, unsigned long); |
| 446 | 446 | |
| 447 | −#define save_altstack_ex(uss, sp) do { \ | |
| 447 | +#define unsafe_save_altstack(uss, sp, label) do { \ | |
| 448 | 448 | stack_t __user *__uss = uss; \ |
| 449 | 449 | struct task_struct *t = current; \ |
| 450 | − put_user_ex((void __user *)t->sas_ss_sp, &__uss->ss_sp); \ | |
| 451 | − put_user_ex(t->sas_ss_flags, &__uss->ss_flags); \ | |
| 452 | − put_user_ex(t->sas_ss_size, &__uss->ss_size); \ | |
| 450 | + unsafe_put_user((void __user *)t->sas_ss_sp, &__uss->ss_sp, label); \ | |
| 451 | + unsafe_put_user(t->sas_ss_flags, &__uss->ss_flags, label); \ | |
| 452 | + unsafe_put_user(t->sas_ss_size, &__uss->ss_size, label); \ | |
| 453 | 453 | if (t->sas_ss_flags & SS_AUTODISARM) \ |
| 454 | 454 | sas_ss_reset(t); \ |
| 455 | 455 | } while (0); |