/* * Based on arch/arm/kernel/signal.c * * Copyright (C) 1995-2009 Russell King * Copyright (C) 2012 ARM Ltd. * Modified by Will Deacon * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ #include #include #include #include #include #include #include #include struct compat_sigaction { compat_uptr_t sa_handler; compat_ulong_t sa_flags; compat_uptr_t sa_restorer; compat_sigset_t sa_mask; }; struct compat_old_sigaction { compat_uptr_t sa_handler; compat_old_sigset_t sa_mask; compat_ulong_t sa_flags; compat_uptr_t sa_restorer; }; struct compat_sigcontext { /* We always set these two fields to 0 */ compat_ulong_t trap_no; compat_ulong_t error_code; compat_ulong_t oldmask; compat_ulong_t arm_r0; compat_ulong_t arm_r1; compat_ulong_t arm_r2; compat_ulong_t arm_r3; compat_ulong_t arm_r4; compat_ulong_t arm_r5; compat_ulong_t arm_r6; compat_ulong_t arm_r7; compat_ulong_t arm_r8; compat_ulong_t arm_r9; compat_ulong_t arm_r10; compat_ulong_t arm_fp; compat_ulong_t arm_ip; compat_ulong_t arm_sp; compat_ulong_t arm_lr; compat_ulong_t arm_pc; compat_ulong_t arm_cpsr; compat_ulong_t fault_address; }; struct compat_ucontext { compat_ulong_t uc_flags; struct compat_ucontext *uc_link; compat_stack_t uc_stack; struct compat_sigcontext uc_mcontext; compat_sigset_t uc_sigmask; int __unused[32 - (sizeof (compat_sigset_t) / sizeof (int))]; compat_ulong_t uc_regspace[128] __attribute__((__aligned__(8))); }; struct compat_vfp_sigframe { compat_ulong_t magic; compat_ulong_t size; struct compat_user_vfp { compat_u64 fpregs[32]; compat_ulong_t fpscr; } ufp; struct compat_user_vfp_exc { compat_ulong_t fpexc; compat_ulong_t fpinst; compat_ulong_t fpinst2; } ufp_exc; } __attribute__((__aligned__(8))); #define VFP_MAGIC 0x56465001 #define VFP_STORAGE_SIZE sizeof(struct compat_vfp_sigframe) struct compat_aux_sigframe { struct compat_vfp_sigframe vfp; /* Something that isn't a valid magic number for any coprocessor. */ unsigned long end_magic; } __attribute__((__aligned__(8))); struct compat_sigframe { struct compat_ucontext uc; compat_ulong_t retcode[2]; }; struct compat_rt_sigframe { struct compat_siginfo info; struct compat_sigframe sig; }; #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) /* * For ARM syscalls, the syscall number has to be loaded into r7. * We do not support an OABI userspace. */ #define MOV_R7_NR_SIGRETURN (0xe3a07000 | __NR_compat_sigreturn) #define SVC_SYS_SIGRETURN (0xef000000 | __NR_compat_sigreturn) #define MOV_R7_NR_RT_SIGRETURN (0xe3a07000 | __NR_compat_rt_sigreturn) #define SVC_SYS_RT_SIGRETURN (0xef000000 | __NR_compat_rt_sigreturn) /* * For Thumb syscalls, we also pass the syscall number via r7. We therefore * need two 16-bit instructions. */ #define SVC_THUMB_SIGRETURN (((0xdf00 | __NR_compat_sigreturn) << 16) | \ 0x2700 | __NR_compat_sigreturn) #define SVC_THUMB_RT_SIGRETURN (((0xdf00 | __NR_compat_rt_sigreturn) << 16) | \ 0x2700 | __NR_compat_rt_sigreturn) const compat_ulong_t aarch32_sigret_code[6] = { /* * AArch32 sigreturn code. * We don't construct an OABI SWI - instead we just set the imm24 field * to the EABI syscall number so that we create a sane disassembly. */ MOV_R7_NR_SIGRETURN, SVC_SYS_SIGRETURN, SVC_THUMB_SIGRETURN, MOV_R7_NR_RT_SIGRETURN, SVC_SYS_RT_SIGRETURN, SVC_THUMB_RT_SIGRETURN, }; static inline int put_sigset_t(compat_sigset_t __user *uset, sigset_t *set) { compat_sigset_t cset; cset.sig[0] = set->sig[0] & 0xffffffffull; cset.sig[1] = set->sig[0] >> 32; return copy_to_user(uset, &cset, sizeof(*uset)); } static inline int get_sigset_t(sigset_t *set, const compat_sigset_t __user *uset) { compat_sigset_t s32; if (copy_from_user(&s32, uset, sizeof(*uset))) return -EFAULT; set->sig[0] = s32.sig[0] | (((long)s32.sig[1]) << 32); return 0; } int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from) { int err; if (!access_ok(VERIFY_WRITE, to, sizeof(*to))) return -EFAULT; /* If you change siginfo_t structure, please be sure * this code is fixed accordingly. * It should never copy any pad contained in the structure * to avoid security leaks, but must copy the generic * 3 ints plus the relevant union member. * This routine must convert siginfo from 64bit to 32bit as well * at the same time. */ err = __put_user(from->si_signo, &to->si_signo); err |= __put_user(from->si_errno, &to->si_errno); err |= __put_user((short)from->si_code, &to->si_code); if (from->si_code < 0) err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE); else switch (from->si_code & __SI_MASK) { case __SI_KILL: err |= __put_user(from->si_pid, &to->si_pid); err |= __put_user(from->si_uid, &to->si_uid); break; case __SI_TIMER: err |= __put_user(from->si_tid, &to->si_tid); err |= __put_user(from->si_overrun, &to->si_overrun); err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr, &to->si_ptr); break; case __SI_POLL: err |= __put_user(from->si_band, &to->si_band); err |= __put_user(from->si_fd, &to->si_fd); break; case __SI_FAULT: err |= __put_user((compat_uptr_t)(unsigned long)from->si_addr, &to->si_addr); #ifdef BUS_MCEERR_AO /* * Other callers might not initialize the si_lsb field, * so check explicitely for the right codes here. */ if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO) err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); #endif break; case __SI_CHLD: err |= __put_user(from->si_pid, &to->si_pid); err |= __put_user(from->si_uid, &to->si_uid); err |= __put_user(from->si_status, &to->si_status); err |= __put_user(from->si_utime, &to->si_utime); err |= __put_user(from->si_stime, &to->si_stime); break; case __SI_RT: /* This is not generated by the kernel as of now. */ case __SI_MESGQ: /* But this is */ err |= __put_user(from->si_pid, &to->si_pid); err |= __put_user(from->si_uid, &to->si_uid); err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr, &to->si_ptr); break; default: /* this is just in case for now ... */ err |= __put_user(from->si_pid, &to->si_pid); err |= __put_user(from->si_uid, &to->si_uid); break; } return err; } int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from) { memset(to, 0, sizeof *to); if (copy_from_user(to, from, __ARCH_SI_PREAMBLE_SIZE) || copy_from_user(to->_sifields._pad, from->_sifields._pad, SI_PAD_SIZE)) return -EFAULT; return 0; } /* * VFP save/restore code. */ static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame) { struct fpsimd_state *fpsimd = ¤t->thread.fpsimd_state; compat_ulong_t magic = VFP_MAGIC; compat_ulong_t size = VFP_STORAGE_SIZE; compat_ulong_t fpscr, fpexc; int err = 0; /* * Save the hardware registers to the fpsimd_state structure. * Note that this also saves V16-31, which aren't visible * in AArch32. */ fpsimd_save_state(fpsimd); /* Place structure header on the stack */ __put_user_error(magic, &frame->magic, err); __put_user_error(size, &frame->size, err); /* * Now copy the FP registers. Since the registers are packed, * we can copy the prefix we want (V0-V15) as it is. * FIXME: Won't work if big endian. */ err |= __copy_to_user(&frame->ufp.fpregs, fpsimd->vregs, sizeof(frame->ufp.fpregs)); /* Create an AArch32 fpscr from the fpsr and the fpcr. */ fpscr = (fpsimd->fpsr & VFP_FPSCR_STAT_MASK) | (fpsimd->fpcr & VFP_FPSCR_CTRL_MASK); __put_user_error(fpscr, &frame->ufp.fpscr, err); /* * The exception register aren't available so we fake up a * basic FPEXC and zero everything else. */ fpexc = (1 << 30); __put_user_error(fpexc, &frame->ufp_exc.fpexc, err); __put_user_error(0, &frame->ufp_exc.fpinst, err); __put_user_error(0, &frame->ufp_exc.fpinst2, err); return err ? -EFAULT : 0; } static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame) { struct fpsimd_state fpsimd; compat_ulong_t magic = VFP_MAGIC; compat_ulong_t size = VFP_STORAGE_SIZE; compat_ulong_t fpscr; int err = 0; __get_user_error(magic, &frame->magic, err); __get_user_error(size, &frame->size, err); if (err) return -EFAULT; if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE) return -EINVAL; /* * Copy the FP registers into the start of the fpsimd_state. * FIXME: Won't work if big endian. */ err |= __copy_from_user(fpsimd.vregs, frame->ufp.fpregs, sizeof(frame->ufp.fpregs)); /* Extract the fpsr and the fpcr from the fpscr */ __get_user_error(fpscr, &frame->ufp.fpscr, err); fpsimd.fpsr = fpscr & VFP_FPSCR_STAT_MASK; fpsimd.fpcr = fpscr & VFP_FPSCR_CTRL_MASK; /* * We don't need to touch the exception register, so * reload the hardware state. */ if (!err) { preempt_disable(); fpsimd_load_state(&fpsimd); preempt_enable(); } return err ? -EFAULT : 0; } /* * atomically swap in the new signal mask, and wait for a signal. */ asmlinkage int compat_sys_sigsuspend(int restart, compat_ulong_t oldmask, compat_old_sigset_t mask) { sigset_t blocked; siginitset(¤t->blocked, mask); return sigsuspend(&blocked); } asmlinkage int compat_sys_sigaction(int sig, const struct compat_old_sigaction __user *act, struct compat_old_sigaction __user *oact) { struct k_sigaction new_ka, old_ka; int ret; compat_old_sigset_t mask; compat_uptr_t handler, restorer; if (act) { if (!access_ok(VERIFY_READ, act, sizeof(*act)) || __get_user(handler, &act->sa_handler) || __get_user(restorer, &act->sa_restorer) || __get_user(new_ka.sa.sa_flags, &act->sa_flags) || __get_user(mask, &act->sa_mask)) return -EFAULT; new_ka.sa.sa_handler = compat_ptr(handler); new_ka.sa.sa_restorer = compat_ptr(restorer); siginitset(&new_ka.sa.sa_mask, mask); } ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); if (!ret && oact) { if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || __put_user(ptr_to_compat(old_ka.sa.sa_handler), &oact->sa_handler) || __put_user(ptr_to_compat(old_ka.sa.sa_restorer), &oact->sa_restorer) || __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) return -EFAULT; } return ret; } asmlinkage int compat_sys_rt_sigaction(int sig, const struct compat_sigaction __user *act, struct compat_sigaction __user *oact, compat_size_t sigsetsize) { struct k_sigaction new_ka, old_ka; int ret; /* XXX: Don't preclude handling different sized sigset_t's. */ if (sigsetsize != sizeof(compat_sigset_t)) return -EINVAL; if (act) { compat_uptr_t handler, restorer; ret = get_user(handler, &act->sa_handler); new_ka.sa.sa_handler = compat_ptr(handler); ret |= get_user(restorer, &act->sa_restorer); new_ka.sa.sa_restorer = compat_ptr(restorer); ret |= get_sigset_t(&new_ka.sa.sa_mask, &act->sa_mask); ret |= __get_user(new_ka.sa.sa_flags, &act->sa_flags); if (ret) return -EFAULT; } ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); if (!ret && oact) { ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), &oact->sa_handler); ret |= put_sigset_t(&oact->sa_mask, &old_ka.sa.sa_mask); ret |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags); } return ret; } static int compat_restore_sigframe(struct pt_regs *regs, struct compat_sigframe __user *sf) { int err; sigset_t set; struct compat_aux_sigframe __user *aux; err = get_sigset_t(&set, &sf->uc.uc_sigmask); if (err == 0) { sigdelsetmask(&set, ~_BLOCKABLE); set_current_blocked(&set); } __get_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err); __get_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err); __get_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err); __get_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err); __get_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err); __get_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err); __get_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err); __get_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err); __get_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err); __get_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err); __get_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err); __get_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err); __get_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err); __get_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err); __get_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err); __get_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err); __get_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err); /* * Avoid compat_sys_sigreturn() restarting. */ regs->syscallno = ~0UL; err |= !valid_user_regs(®s->user_regs); aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace; if (err == 0) err |= compat_restore_vfp_context(&aux->vfp); return err; } asmlinkage int compat_sys_sigreturn(struct pt_regs *regs) { struct compat_sigframe __user *frame; /* Always make any pending restarted system calls return -EINTR */ current_thread_info()->restart_block.fn = do_no_restart_syscall; /* * Since we stacked the signal on a 64-bit boundary, * then 'sp' should be word aligned here. If it's * not, then the user is trying to mess with us. */ if (regs->compat_sp & 7) goto badframe; frame = (struct compat_sigframe __user *)regs->compat_sp; if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) goto badframe; if (compat_restore_sigframe(regs, frame)) goto badframe; return regs->regs[0]; badframe: if (show_unhandled_signals) pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n", current->comm, task_pid_nr(current), __func__, regs->pc, regs->sp); force_sig(SIGSEGV, current); return 0; } asmlinkage int compat_sys_rt_sigreturn(struct pt_regs *regs) { struct compat_rt_sigframe __user *frame; /* Always make any pending restarted system calls return -EINTR */ current_thread_info()->restart_block.fn = do_no_restart_syscall; /* * Since we stacked the signal on a 64-bit boundary, * then 'sp' should be word aligned here. If it's * not, then the user is trying to mess with us. */ if (regs->compat_sp & 7) goto badframe; frame = (struct compat_rt_sigframe __user *)regs->compat_sp; if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) goto badframe; if (compat_restore_sigframe(regs, &frame->sig)) goto badframe; if (compat_restore_altstack(&frame->sig.uc.uc_stack)) goto badframe; return regs->regs[0]; badframe: if (show_unhandled_signals) pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n", current->comm, task_pid_nr(current), __func__, regs->pc, regs->sp); force_sig(SIGSEGV, current); return 0; } static void __user *compat_get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize) { compat_ulong_t sp = regs->compat_sp; void __user *frame; /* * This is the X/Open sanctioned signal stack switching. */ if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp)) sp = current->sas_ss_sp + current->sas_ss_size; /* * ATPCS B01 mandates 8-byte alignment */ frame = compat_ptr((compat_uptr_t)((sp - framesize) & ~7)); /* * Check that we can actually write to the signal frame. */ if (!access_ok(VERIFY_WRITE, frame, framesize)) frame = NULL; return frame; } static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka, compat_ulong_t __user *rc, void __user *frame, int usig) { compat_ulong_t handler = ptr_to_compat(ka->sa.sa_handler); compat_ulong_t retcode; compat_ulong_t spsr = regs->pstate & ~PSR_f; int thumb; /* Check if the handler is written for ARM or Thumb */ thumb = handler & 1; if (thumb) { spsr |= COMPAT_PSR_T_BIT; spsr &= ~COMPAT_PSR_IT_MASK; } else { spsr &= ~COMPAT_PSR_T_BIT; } if (ka->sa.sa_flags & SA_RESTORER) { retcode = ptr_to_compat(ka->sa.sa_restorer); } else { /* Set up sigreturn pointer */ unsigned int idx = thumb << 1; if (ka->sa.sa_flags & SA_SIGINFO) idx += 3; retcode = AARCH32_VECTORS_BASE + AARCH32_KERN_SIGRET_CODE_OFFSET + (idx << 2) + thumb; } regs->regs[0] = usig; regs->compat_sp = ptr_to_compat(frame); regs->compat_lr = retcode; regs->pc = handler; regs->pstate = spsr; } static int compat_setup_sigframe(struct compat_sigframe __user *sf, struct pt_regs *regs, sigset_t *set) { struct compat_aux_sigframe __user *aux; int err = 0; __put_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err); __put_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err); __put_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err); __put_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err); __put_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err); __put_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err); __put_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err); __put_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err); __put_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err); __put_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err); __put_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err); __put_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err); __put_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err); __put_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err); __put_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err); __put_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err); __put_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err); __put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.trap_no, err); __put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.error_code, err); __put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err); __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err); err |= put_sigset_t(&sf->uc.uc_sigmask, set); aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace; if (err == 0) err |= compat_preserve_vfp_context(&aux->vfp); __put_user_error(0, &aux->end_magic, err); return err; } /* * 32-bit signal handling routines called from signal.c */ int compat_setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set, struct pt_regs *regs) { struct compat_rt_sigframe __user *frame; compat_stack_t stack; int err = 0; frame = compat_get_sigframe(ka, regs, sizeof(*frame)); if (!frame) return 1; err |= copy_siginfo_to_user32(&frame->info, info); __put_user_error(0, &frame->sig.uc.uc_flags, err); __put_user_error(NULL, &frame->sig.uc.uc_link, err); err |= __compat_save_altstack(&frame->sig.uc.uc_stack, regs->compat_sp); err |= compat_setup_sigframe(&frame->sig, regs, set); if (err == 0) { compat_setup_return(regs, ka, frame->sig.retcode, frame, usig); regs->regs[1] = (compat_ulong_t)(unsigned long)&frame->info; regs->regs[2] = (compat_ulong_t)(unsigned long)&frame->sig.uc; } return err; } int compat_setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs) { struct compat_sigframe __user *frame; int err = 0; frame = compat_get_sigframe(ka, regs, sizeof(*frame)); if (!frame) return 1; __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err); err |= compat_setup_sigframe(frame, regs, set); if (err == 0) compat_setup_return(regs, ka, frame->retcode, frame, usig); return err; } asmlinkage int compat_sys_rt_sigqueueinfo(int pid, int sig, compat_siginfo_t __user *uinfo) { siginfo_t info; int ret; mm_segment_t old_fs = get_fs(); ret = copy_siginfo_from_user32(&info, uinfo); if (unlikely(ret)) return ret; set_fs (KERNEL_DS); /* The __user pointer cast is valid because of the set_fs() */ ret = sys_rt_sigqueueinfo(pid, sig, (siginfo_t __user *) &info); set_fs (old_fs); return ret; } void compat_setup_restart_syscall(struct pt_regs *regs) { regs->regs[7] = __NR_compat_restart_syscall; }