diff options
Diffstat (limited to 'arch/powerpc/kernel/signal_64.c')
-rw-r--r-- | arch/powerpc/kernel/signal_64.c | 319 |
1 files changed, 189 insertions, 130 deletions
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c index f9e4a1ac440f..dca66481d0c2 100644 --- a/arch/powerpc/kernel/signal_64.c +++ b/arch/powerpc/kernel/signal_64.c @@ -79,13 +79,36 @@ static elf_vrreg_t __user *sigcontext_vmx_regs(struct sigcontext __user *sc) } #endif +static void prepare_setup_sigcontext(struct task_struct *tsk) +{ +#ifdef CONFIG_ALTIVEC + /* save altivec registers */ + if (tsk->thread.used_vr) + flush_altivec_to_thread(tsk); + if (cpu_has_feature(CPU_FTR_ALTIVEC)) + tsk->thread.vrsave = mfspr(SPRN_VRSAVE); +#endif /* CONFIG_ALTIVEC */ + + flush_fp_to_thread(tsk); + +#ifdef CONFIG_VSX + if (tsk->thread.used_vsr) + flush_vsx_to_thread(tsk); +#endif /* CONFIG_VSX */ +} + /* * Set up the sigcontext for the signal frame. */ -static long setup_sigcontext(struct sigcontext __user *sc, - struct task_struct *tsk, int signr, sigset_t *set, - unsigned long handler, int ctx_has_vsx_region) +#define unsafe_setup_sigcontext(sc, tsk, signr, set, handler, ctx_has_vsx_region, label)\ +do { \ + if (__unsafe_setup_sigcontext(sc, tsk, signr, set, handler, ctx_has_vsx_region))\ + goto label; \ +} while (0) +static long notrace __unsafe_setup_sigcontext(struct sigcontext __user *sc, + struct task_struct *tsk, int signr, sigset_t *set, + unsigned long handler, int ctx_has_vsx_region) { /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the * process never used altivec yet (MSR_VEC is zero in pt_regs of @@ -97,25 +120,22 @@ static long setup_sigcontext(struct sigcontext __user *sc, */ #ifdef CONFIG_ALTIVEC elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc); - unsigned long vrsave; #endif struct pt_regs *regs = tsk->thread.regs; unsigned long msr = regs->msr; - long err = 0; /* Force usr to alway see softe as 1 (interrupts enabled) */ unsigned long softe = 0x1; BUG_ON(tsk != current); #ifdef CONFIG_ALTIVEC - err |= __put_user(v_regs, &sc->v_regs); + unsafe_put_user(v_regs, &sc->v_regs, efault_out); /* save altivec registers */ if (tsk->thread.used_vr) { - flush_altivec_to_thread(tsk); /* Copy 33 vec registers (vr0..31 and vscr) to the stack */ - err |= __copy_to_user(v_regs, &tsk->thread.vr_state, - 33 * sizeof(vector128)); + unsafe_copy_to_user(v_regs, &tsk->thread.vr_state, + 33 * sizeof(vector128), efault_out); /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg) * contains valid data. */ @@ -124,19 +144,12 @@ static long setup_sigcontext(struct sigcontext __user *sc, /* We always copy to/from vrsave, it's 0 if we don't have or don't * use altivec. */ - vrsave = 0; - if (cpu_has_feature(CPU_FTR_ALTIVEC)) { - vrsave = mfspr(SPRN_VRSAVE); - tsk->thread.vrsave = vrsave; - } - - err |= __put_user(vrsave, (u32 __user *)&v_regs[33]); + unsafe_put_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out); #else /* CONFIG_ALTIVEC */ - err |= __put_user(0, &sc->v_regs); + unsafe_put_user(0, &sc->v_regs, efault_out); #endif /* CONFIG_ALTIVEC */ - flush_fp_to_thread(tsk); /* copy fpr regs and fpscr */ - err |= copy_fpr_to_user(&sc->fp_regs, tsk); + unsafe_copy_fpr_to_user(&sc->fp_regs, tsk, efault_out); /* * Clear the MSR VSX bit to indicate there is no valid state attached @@ -150,26 +163,27 @@ static long setup_sigcontext(struct sigcontext __user *sc, * VMX data. */ if (tsk->thread.used_vsr && ctx_has_vsx_region) { - flush_vsx_to_thread(tsk); v_regs += ELF_NVRREG; - err |= copy_vsx_to_user(v_regs, tsk); + unsafe_copy_vsx_to_user(v_regs, tsk, efault_out); /* set MSR_VSX in the MSR value in the frame to * indicate that sc->vs_reg) contains valid data. */ msr |= MSR_VSX; } #endif /* CONFIG_VSX */ - err |= __put_user(&sc->gp_regs, &sc->regs); - WARN_ON(!FULL_REGS(regs)); - err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE); - err |= __put_user(msr, &sc->gp_regs[PT_MSR]); - err |= __put_user(softe, &sc->gp_regs[PT_SOFTE]); - err |= __put_user(signr, &sc->signal); - err |= __put_user(handler, &sc->handler); + unsafe_put_user(&sc->gp_regs, &sc->regs, efault_out); + unsafe_copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE, efault_out); + unsafe_put_user(msr, &sc->gp_regs[PT_MSR], efault_out); + unsafe_put_user(softe, &sc->gp_regs[PT_SOFTE], efault_out); + unsafe_put_user(signr, &sc->signal, efault_out); + unsafe_put_user(handler, &sc->handler, efault_out); if (set != NULL) - err |= __put_user(set->sig[0], &sc->oldmask); + unsafe_put_user(set->sig[0], &sc->oldmask, efault_out); - return err; + return 0; + +efault_out: + return -EFAULT; } #ifdef CONFIG_PPC_TRANSACTIONAL_MEM @@ -294,7 +308,6 @@ static long setup_tm_sigcontexts(struct sigcontext __user *sc, err |= __put_user(&sc->gp_regs, &sc->regs); err |= __put_user(&tm_sc->gp_regs, &tm_sc->regs); - WARN_ON(!FULL_REGS(regs)); err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE); err |= __copy_to_user(&sc->gp_regs, &tsk->thread.ckpt_regs, GP_REGS_SIZE); @@ -312,14 +325,16 @@ static long setup_tm_sigcontexts(struct sigcontext __user *sc, /* * Restore the sigcontext from the signal frame. */ - -static long restore_sigcontext(struct task_struct *tsk, sigset_t *set, int sig, - struct sigcontext __user *sc) +#define unsafe_restore_sigcontext(tsk, set, sig, sc, label) do { \ + if (__unsafe_restore_sigcontext(tsk, set, sig, sc)) \ + goto label; \ +} while (0) +static long notrace __unsafe_restore_sigcontext(struct task_struct *tsk, sigset_t *set, + int sig, struct sigcontext __user *sc) { #ifdef CONFIG_ALTIVEC elf_vrreg_t __user *v_regs; #endif - unsigned long err = 0; unsigned long save_r13 = 0; unsigned long msr; struct pt_regs *regs = tsk->thread.regs; @@ -334,27 +349,27 @@ static long restore_sigcontext(struct task_struct *tsk, sigset_t *set, int sig, save_r13 = regs->gpr[13]; /* copy the GPRs */ - err |= __copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr)); - err |= __get_user(regs->nip, &sc->gp_regs[PT_NIP]); + unsafe_copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr), efault_out); + unsafe_get_user(regs->nip, &sc->gp_regs[PT_NIP], efault_out); /* get MSR separately, transfer the LE bit if doing signal return */ - err |= __get_user(msr, &sc->gp_regs[PT_MSR]); + unsafe_get_user(msr, &sc->gp_regs[PT_MSR], efault_out); if (sig) regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE); - err |= __get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3]); - err |= __get_user(regs->ctr, &sc->gp_regs[PT_CTR]); - err |= __get_user(regs->link, &sc->gp_regs[PT_LNK]); - err |= __get_user(regs->xer, &sc->gp_regs[PT_XER]); - err |= __get_user(regs->ccr, &sc->gp_regs[PT_CCR]); + unsafe_get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3], efault_out); + unsafe_get_user(regs->ctr, &sc->gp_regs[PT_CTR], efault_out); + unsafe_get_user(regs->link, &sc->gp_regs[PT_LNK], efault_out); + unsafe_get_user(regs->xer, &sc->gp_regs[PT_XER], efault_out); + unsafe_get_user(regs->ccr, &sc->gp_regs[PT_CCR], efault_out); /* Don't allow userspace to set SOFTE */ set_trap_norestart(regs); - err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]); - err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]); - err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]); + unsafe_get_user(regs->dar, &sc->gp_regs[PT_DAR], efault_out); + unsafe_get_user(regs->dsisr, &sc->gp_regs[PT_DSISR], efault_out); + unsafe_get_user(regs->result, &sc->gp_regs[PT_RESULT], efault_out); if (!sig) regs->gpr[13] = save_r13; if (set != NULL) - err |= __get_user(set->sig[0], &sc->oldmask); + unsafe_get_user(set->sig[0], &sc->oldmask, efault_out); /* * Force reload of FP/VEC. @@ -364,29 +379,27 @@ static long restore_sigcontext(struct task_struct *tsk, sigset_t *set, int sig, regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX); #ifdef CONFIG_ALTIVEC - err |= __get_user(v_regs, &sc->v_regs); - if (err) - return err; + unsafe_get_user(v_regs, &sc->v_regs, efault_out); if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128))) return -EFAULT; /* Copy 33 vec registers (vr0..31 and vscr) from the stack */ if (v_regs != NULL && (msr & MSR_VEC) != 0) { - err |= __copy_from_user(&tsk->thread.vr_state, v_regs, - 33 * sizeof(vector128)); + unsafe_copy_from_user(&tsk->thread.vr_state, v_regs, + 33 * sizeof(vector128), efault_out); tsk->thread.used_vr = true; } else if (tsk->thread.used_vr) { memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128)); } /* Always get VRSAVE back */ if (v_regs != NULL) - err |= __get_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33]); + unsafe_get_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out); else tsk->thread.vrsave = 0; if (cpu_has_feature(CPU_FTR_ALTIVEC)) mtspr(SPRN_VRSAVE, tsk->thread.vrsave); #endif /* CONFIG_ALTIVEC */ /* restore floating point */ - err |= copy_fpr_from_user(tsk, &sc->fp_regs); + unsafe_copy_fpr_from_user(tsk, &sc->fp_regs, efault_out); #ifdef CONFIG_VSX /* * Get additional VSX data. Update v_regs to point after the @@ -395,14 +408,17 @@ static long restore_sigcontext(struct task_struct *tsk, sigset_t *set, int sig, */ v_regs += ELF_NVRREG; if ((msr & MSR_VSX) != 0) { - err |= copy_vsx_from_user(tsk, v_regs); + unsafe_copy_vsx_from_user(tsk, v_regs, efault_out); tsk->thread.used_vsr = true; } else { for (i = 0; i < 32 ; i++) tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0; } #endif - return err; + return 0; + +efault_out: + return -EFAULT; } #ifdef CONFIG_PPC_TRANSACTIONAL_MEM @@ -586,6 +602,12 @@ static long restore_tm_sigcontexts(struct task_struct *tsk, return err; } +#else /* !CONFIG_PPC_TRANSACTIONAL_MEM */ +static long restore_tm_sigcontexts(struct task_struct *tsk, struct sigcontext __user *sc, + struct sigcontext __user *tm_sc) +{ + return -EINVAL; +} #endif /* @@ -655,12 +677,16 @@ SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx, ctx_has_vsx_region = 1; if (old_ctx != NULL) { - if (!access_ok(old_ctx, ctx_size) - || setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL, 0, - ctx_has_vsx_region) - || __copy_to_user(&old_ctx->uc_sigmask, - ¤t->blocked, sizeof(sigset_t))) + prepare_setup_sigcontext(current); + if (!user_write_access_begin(old_ctx, ctx_size)) return -EFAULT; + + unsafe_setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL, + 0, ctx_has_vsx_region, efault_out); + unsafe_copy_to_user(&old_ctx->uc_sigmask, ¤t->blocked, + sizeof(sigset_t), efault_out); + + user_write_access_end(); } if (new_ctx == NULL) return 0; @@ -680,15 +706,25 @@ SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx, * We kill the task with a SIGSEGV in this situation. */ - if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set))) + if (__get_user_sigset(&set, &new_ctx->uc_sigmask)) do_exit(SIGSEGV); set_current_blocked(&set); - if (restore_sigcontext(current, NULL, 0, &new_ctx->uc_mcontext)) + + if (!user_read_access_begin(new_ctx, ctx_size)) + return -EFAULT; + if (__unsafe_restore_sigcontext(current, NULL, 0, &new_ctx->uc_mcontext)) { + user_read_access_end(); do_exit(SIGSEGV); + } + user_read_access_end(); /* This returns like rt_sigreturn */ set_thread_flag(TIF_RESTOREALL); return 0; + +efault_out: + user_write_access_end(); + return -EFAULT; } @@ -701,9 +737,7 @@ SYSCALL_DEFINE0(rt_sigreturn) struct pt_regs *regs = current_pt_regs(); struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1]; sigset_t set; -#ifdef CONFIG_PPC_TRANSACTIONAL_MEM unsigned long msr; -#endif /* Always make any pending restarted system calls return -EINTR */ current->restart_block.fn = do_no_restart_syscall; @@ -711,52 +745,54 @@ SYSCALL_DEFINE0(rt_sigreturn) if (!access_ok(uc, sizeof(*uc))) goto badframe; - if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set))) + if (__get_user_sigset(&set, &uc->uc_sigmask)) goto badframe; set_current_blocked(&set); -#ifdef CONFIG_PPC_TRANSACTIONAL_MEM - /* - * If there is a transactional state then throw it away. - * The purpose of a sigreturn is to destroy all traces of the - * signal frame, this includes any transactional state created - * within in. We only check for suspended as we can never be - * active in the kernel, we are active, there is nothing better to - * do than go ahead and Bad Thing later. - * The cause is not important as there will never be a - * recheckpoint so it's not user visible. - */ - if (MSR_TM_SUSPENDED(mfmsr())) - tm_reclaim_current(0); + if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM)) { + /* + * If there is a transactional state then throw it away. + * The purpose of a sigreturn is to destroy all traces of the + * signal frame, this includes any transactional state created + * within in. We only check for suspended as we can never be + * active in the kernel, we are active, there is nothing better to + * do than go ahead and Bad Thing later. + * The cause is not important as there will never be a + * recheckpoint so it's not user visible. + */ + if (MSR_TM_SUSPENDED(mfmsr())) + tm_reclaim_current(0); - /* - * Disable MSR[TS] bit also, so, if there is an exception in the - * code below (as a page fault in copy_ckvsx_to_user()), it does - * not recheckpoint this task if there was a context switch inside - * the exception. - * - * A major page fault can indirectly call schedule(). A reschedule - * process in the middle of an exception can have a side effect - * (Changing the CPU MSR[TS] state), since schedule() is called - * with the CPU MSR[TS] disable and returns with MSR[TS]=Suspended - * (switch_to() calls tm_recheckpoint() for the 'new' process). In - * this case, the process continues to be the same in the CPU, but - * the CPU state just changed. - * - * This can cause a TM Bad Thing, since the MSR in the stack will - * have the MSR[TS]=0, and this is what will be used to RFID. - * - * Clearing MSR[TS] state here will avoid a recheckpoint if there - * is any process reschedule in kernel space. The MSR[TS] state - * does not need to be saved also, since it will be replaced with - * the MSR[TS] that came from user context later, at - * restore_tm_sigcontexts. - */ - regs->msr &= ~MSR_TS_MASK; + /* + * Disable MSR[TS] bit also, so, if there is an exception in the + * code below (as a page fault in copy_ckvsx_to_user()), it does + * not recheckpoint this task if there was a context switch inside + * the exception. + * + * A major page fault can indirectly call schedule(). A reschedule + * process in the middle of an exception can have a side effect + * (Changing the CPU MSR[TS] state), since schedule() is called + * with the CPU MSR[TS] disable and returns with MSR[TS]=Suspended + * (switch_to() calls tm_recheckpoint() for the 'new' process). In + * this case, the process continues to be the same in the CPU, but + * the CPU state just changed. + * + * This can cause a TM Bad Thing, since the MSR in the stack will + * have the MSR[TS]=0, and this is what will be used to RFID. + * + * Clearing MSR[TS] state here will avoid a recheckpoint if there + * is any process reschedule in kernel space. The MSR[TS] state + * does not need to be saved also, since it will be replaced with + * the MSR[TS] that came from user context later, at + * restore_tm_sigcontexts. + */ + regs->msr &= ~MSR_TS_MASK; - if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR])) - goto badframe; - if (MSR_TM_ACTIVE(msr)) { + if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR])) + goto badframe; + } + + if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) && MSR_TM_ACTIVE(msr)) { /* We recheckpoint on return. */ struct ucontext __user *uc_transact; @@ -769,9 +805,7 @@ SYSCALL_DEFINE0(rt_sigreturn) if (restore_tm_sigcontexts(current, &uc->uc_mcontext, &uc_transact->uc_mcontext)) goto badframe; - } else -#endif - { + } else { /* * Fall through, for non-TM restore * @@ -785,8 +819,13 @@ SYSCALL_DEFINE0(rt_sigreturn) * causing a TM bad thing. */ current->thread.regs->msr &= ~MSR_TS_MASK; - if (restore_sigcontext(current, NULL, 1, &uc->uc_mcontext)) + if (!user_read_access_begin(&uc->uc_mcontext, sizeof(uc->uc_mcontext))) goto badframe; + + unsafe_restore_sigcontext(current, NULL, 1, &uc->uc_mcontext, + badframe_block); + + user_read_access_end(); } if (restore_altstack(&uc->uc_stack)) @@ -795,6 +834,8 @@ SYSCALL_DEFINE0(rt_sigreturn) set_thread_flag(TIF_RESTOREALL); return 0; +badframe_block: + user_read_access_end(); badframe: signal_fault(current, regs, "rt_sigreturn", uc); @@ -809,46 +850,57 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, unsigned long newsp = 0; long err = 0; struct pt_regs *regs = tsk->thread.regs; -#ifdef CONFIG_PPC_TRANSACTIONAL_MEM /* Save the thread's msr before get_tm_stackpointer() changes it */ unsigned long msr = regs->msr; -#endif frame = get_sigframe(ksig, tsk, sizeof(*frame), 0); - if (!access_ok(frame, sizeof(*frame))) - goto badframe; - err |= __put_user(&frame->info, &frame->pinfo); - err |= __put_user(&frame->uc, &frame->puc); - err |= copy_siginfo_to_user(&frame->info, &ksig->info); - if (err) + /* + * This only applies when calling unsafe_setup_sigcontext() and must be + * called before opening the uaccess window. + */ + if (!MSR_TM_ACTIVE(msr)) + prepare_setup_sigcontext(tsk); + + if (!user_write_access_begin(frame, sizeof(*frame))) goto badframe; + unsafe_put_user(&frame->info, &frame->pinfo, badframe_block); + unsafe_put_user(&frame->uc, &frame->puc, badframe_block); + /* Create the ucontext. */ - err |= __put_user(0, &frame->uc.uc_flags); - err |= __save_altstack(&frame->uc.uc_stack, regs->gpr[1]); -#ifdef CONFIG_PPC_TRANSACTIONAL_MEM + unsafe_put_user(0, &frame->uc.uc_flags, badframe_block); + unsafe_save_altstack(&frame->uc.uc_stack, regs->gpr[1], badframe_block); + if (MSR_TM_ACTIVE(msr)) { +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM /* The ucontext_t passed to userland points to the second * ucontext_t (for transactional state) with its uc_link ptr. */ - err |= __put_user(&frame->uc_transact, &frame->uc.uc_link); + unsafe_put_user(&frame->uc_transact, &frame->uc.uc_link, badframe_block); + + user_write_access_end(); + err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext, &frame->uc_transact.uc_mcontext, tsk, ksig->sig, NULL, (unsigned long)ksig->ka.sa.sa_handler, msr); - } else + + if (!user_write_access_begin(&frame->uc.uc_sigmask, + sizeof(frame->uc.uc_sigmask))) + goto badframe; + #endif - { - err |= __put_user(0, &frame->uc.uc_link); - err |= setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig, + } else { + unsafe_put_user(0, &frame->uc.uc_link, badframe_block); + unsafe_setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig, NULL, (unsigned long)ksig->ka.sa.sa_handler, - 1); + 1, badframe_block); } - err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); - if (err) - goto badframe; + + unsafe_copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set), badframe_block); + user_write_access_end(); /* Make sure signal handler doesn't get spurious FP exceptions */ tsk->thread.fp_state.fpscr = 0; @@ -863,6 +915,11 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, regs->nip = (unsigned long) &frame->tramp[0]; } + + /* Save the siginfo outside of the unsafe block. */ + if (copy_siginfo_to_user(&frame->info, &ksig->info)) + goto badframe; + /* Allocate a dummy caller frame for the signal handler. */ newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE; err |= put_user(regs->gpr[1], (unsigned long __user *)newsp); @@ -902,6 +959,8 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, return 0; +badframe_block: + user_write_access_end(); badframe: signal_fault(current, regs, "handle_rt_signal64", frame); |