From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- arch/x86/kernel/signal_32.c | 507 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 507 insertions(+) create mode 100644 arch/x86/kernel/signal_32.c (limited to 'arch/x86/kernel/signal_32.c') diff --git a/arch/x86/kernel/signal_32.c b/arch/x86/kernel/signal_32.c new file mode 100644 index 0000000000..c12624bc82 --- /dev/null +++ b/arch/x86/kernel/signal_32.c @@ -0,0 +1,507 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 1991, 1992 Linus Torvalds + * + * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson + * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes + * 2000-12-* x86-64 compatibility mode signal handling by Andi Kleen + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#ifdef CONFIG_IA32_EMULATION +#include + +static inline void reload_segments(struct sigcontext_32 *sc) +{ + unsigned int cur; + + savesegment(gs, cur); + if ((sc->gs | 0x03) != cur) + load_gs_index(sc->gs | 0x03); + savesegment(fs, cur); + if ((sc->fs | 0x03) != cur) + loadsegment(fs, sc->fs | 0x03); + savesegment(ds, cur); + if ((sc->ds | 0x03) != cur) + loadsegment(ds, sc->ds | 0x03); + savesegment(es, cur); + if ((sc->es | 0x03) != cur) + loadsegment(es, sc->es | 0x03); +} + +#define sigset32_t compat_sigset_t +#define siginfo32_t compat_siginfo_t +#define restore_altstack32 compat_restore_altstack +#define unsafe_save_altstack32 unsafe_compat_save_altstack + +#else + +#define sigset32_t sigset_t +#define siginfo32_t siginfo_t +#define __NR_ia32_sigreturn __NR_sigreturn +#define __NR_ia32_rt_sigreturn __NR_rt_sigreturn +#define restore_altstack32 restore_altstack +#define unsafe_save_altstack32 unsafe_save_altstack +#define __copy_siginfo_to_user32 copy_siginfo_to_user + +#endif + +/* + * Do a signal return; undo the signal stack. + */ +static bool ia32_restore_sigcontext(struct pt_regs *regs, + struct sigcontext_32 __user *usc) +{ + struct sigcontext_32 sc; + + /* Always make any pending restarted system calls return -EINTR */ + current->restart_block.fn = do_no_restart_syscall; + + if (unlikely(copy_from_user(&sc, usc, sizeof(sc)))) + return false; + + /* Get only the ia32 registers. */ + regs->bx = sc.bx; + regs->cx = sc.cx; + regs->dx = sc.dx; + regs->si = sc.si; + regs->di = sc.di; + regs->bp = sc.bp; + regs->ax = sc.ax; + regs->sp = sc.sp; + regs->ip = sc.ip; + + /* Get CS/SS and force CPL3 */ + regs->cs = sc.cs | 0x03; + regs->ss = sc.ss | 0x03; + + regs->flags = (regs->flags & ~FIX_EFLAGS) | (sc.flags & FIX_EFLAGS); + /* disable syscall checks */ + regs->orig_ax = -1; + +#ifdef CONFIG_IA32_EMULATION + /* + * Reload fs and gs if they have changed in the signal + * handler. This does not handle long fs/gs base changes in + * the handler, but does not clobber them at least in the + * normal case. + */ + reload_segments(&sc); +#else + loadsegment(gs, sc.gs); + regs->fs = sc.fs; + regs->es = sc.es; + regs->ds = sc.ds; +#endif + + return fpu__restore_sig(compat_ptr(sc.fpstate), 1); +} + +SYSCALL32_DEFINE0(sigreturn) +{ + struct pt_regs *regs = current_pt_regs(); + struct sigframe_ia32 __user *frame = (struct sigframe_ia32 __user *)(regs->sp-8); + sigset_t set; + + if (!access_ok(frame, sizeof(*frame))) + goto badframe; + if (__get_user(set.sig[0], &frame->sc.oldmask) + || __get_user(((__u32 *)&set)[1], &frame->extramask[0])) + goto badframe; + + set_current_blocked(&set); + + if (!ia32_restore_sigcontext(regs, &frame->sc)) + goto badframe; + return regs->ax; + +badframe: + signal_fault(regs, frame, "32bit sigreturn"); + return 0; +} + +SYSCALL32_DEFINE0(rt_sigreturn) +{ + struct pt_regs *regs = current_pt_regs(); + struct rt_sigframe_ia32 __user *frame; + sigset_t set; + + frame = (struct rt_sigframe_ia32 __user *)(regs->sp - 4); + + if (!access_ok(frame, sizeof(*frame))) + goto badframe; + if (__get_user(*(__u64 *)&set, (__u64 __user *)&frame->uc.uc_sigmask)) + goto badframe; + + set_current_blocked(&set); + + if (!ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext)) + goto badframe; + + if (restore_altstack32(&frame->uc.uc_stack)) + goto badframe; + + return regs->ax; + +badframe: + signal_fault(regs, frame, "32bit rt sigreturn"); + return 0; +} + +/* + * Set up a signal frame. + */ + +#define get_user_seg(seg) ({ unsigned int v; savesegment(seg, v); v; }) + +static __always_inline int +__unsafe_setup_sigcontext32(struct sigcontext_32 __user *sc, + void __user *fpstate, + struct pt_regs *regs, unsigned int mask) +{ + unsafe_put_user(get_user_seg(gs), (unsigned int __user *)&sc->gs, Efault); +#ifdef CONFIG_IA32_EMULATION + unsafe_put_user(get_user_seg(fs), (unsigned int __user *)&sc->fs, Efault); + unsafe_put_user(get_user_seg(ds), (unsigned int __user *)&sc->ds, Efault); + unsafe_put_user(get_user_seg(es), (unsigned int __user *)&sc->es, Efault); +#else + unsafe_put_user(regs->fs, (unsigned int __user *)&sc->fs, Efault); + unsafe_put_user(regs->es, (unsigned int __user *)&sc->es, Efault); + unsafe_put_user(regs->ds, (unsigned int __user *)&sc->ds, Efault); +#endif + + unsafe_put_user(regs->di, &sc->di, Efault); + unsafe_put_user(regs->si, &sc->si, Efault); + unsafe_put_user(regs->bp, &sc->bp, Efault); + unsafe_put_user(regs->sp, &sc->sp, Efault); + unsafe_put_user(regs->bx, &sc->bx, Efault); + unsafe_put_user(regs->dx, &sc->dx, Efault); + unsafe_put_user(regs->cx, &sc->cx, Efault); + unsafe_put_user(regs->ax, &sc->ax, Efault); + unsafe_put_user(current->thread.trap_nr, &sc->trapno, Efault); + unsafe_put_user(current->thread.error_code, &sc->err, Efault); + unsafe_put_user(regs->ip, &sc->ip, Efault); + unsafe_put_user(regs->cs, (unsigned int __user *)&sc->cs, Efault); + unsafe_put_user(regs->flags, &sc->flags, Efault); + unsafe_put_user(regs->sp, &sc->sp_at_signal, Efault); + unsafe_put_user(regs->ss, (unsigned int __user *)&sc->ss, Efault); + + unsafe_put_user(ptr_to_compat(fpstate), &sc->fpstate, Efault); + + /* non-iBCS2 extensions.. */ + unsafe_put_user(mask, &sc->oldmask, Efault); + unsafe_put_user(current->thread.cr2, &sc->cr2, Efault); + return 0; + +Efault: + return -EFAULT; +} + +#define unsafe_put_sigcontext32(sc, fp, regs, set, label) \ +do { \ + if (__unsafe_setup_sigcontext32(sc, fp, regs, set->sig[0])) \ + goto label; \ +} while(0) + +int ia32_setup_frame(struct ksignal *ksig, struct pt_regs *regs) +{ + sigset32_t *set = (sigset32_t *) sigmask_to_save(); + struct sigframe_ia32 __user *frame; + void __user *restorer; + void __user *fp = NULL; + + /* copy_to_user optimizes that into a single 8 byte store */ + static const struct { + u16 poplmovl; + u32 val; + u16 int80; + } __attribute__((packed)) code = { + 0xb858, /* popl %eax ; movl $...,%eax */ + __NR_ia32_sigreturn, + 0x80cd, /* int $0x80 */ + }; + + frame = get_sigframe(ksig, regs, sizeof(*frame), &fp); + + if (ksig->ka.sa.sa_flags & SA_RESTORER) { + restorer = ksig->ka.sa.sa_restorer; + } else { + /* Return stub is in 32bit vsyscall page */ + if (current->mm->context.vdso) + restorer = current->mm->context.vdso + + vdso_image_32.sym___kernel_sigreturn; + else + restorer = &frame->retcode; + } + + if (!user_access_begin(frame, sizeof(*frame))) + return -EFAULT; + + unsafe_put_user(ksig->sig, &frame->sig, Efault); + unsafe_put_sigcontext32(&frame->sc, fp, regs, set, Efault); + unsafe_put_user(set->sig[1], &frame->extramask[0], Efault); + unsafe_put_user(ptr_to_compat(restorer), &frame->pretcode, Efault); + /* + * These are actually not used anymore, but left because some + * gdb versions depend on them as a marker. + */ + unsafe_put_user(*((u64 *)&code), (u64 __user *)frame->retcode, Efault); + user_access_end(); + + /* Set up registers for signal handler */ + regs->sp = (unsigned long) frame; + regs->ip = (unsigned long) ksig->ka.sa.sa_handler; + + /* Make -mregparm=3 work */ + regs->ax = ksig->sig; + regs->dx = 0; + regs->cx = 0; + +#ifdef CONFIG_IA32_EMULATION + loadsegment(ds, __USER_DS); + loadsegment(es, __USER_DS); +#else + regs->ds = __USER_DS; + regs->es = __USER_DS; +#endif + + regs->cs = __USER32_CS; + regs->ss = __USER_DS; + + return 0; +Efault: + user_access_end(); + return -EFAULT; +} + +int ia32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) +{ + sigset32_t *set = (sigset32_t *) sigmask_to_save(); + struct rt_sigframe_ia32 __user *frame; + void __user *restorer; + void __user *fp = NULL; + + /* unsafe_put_user optimizes that into a single 8 byte store */ + static const struct { + u8 movl; + u32 val; + u16 int80; + u8 pad; + } __attribute__((packed)) code = { + 0xb8, + __NR_ia32_rt_sigreturn, + 0x80cd, + 0, + }; + + frame = get_sigframe(ksig, regs, sizeof(*frame), &fp); + + if (!user_access_begin(frame, sizeof(*frame))) + return -EFAULT; + + unsafe_put_user(ksig->sig, &frame->sig, Efault); + unsafe_put_user(ptr_to_compat(&frame->info), &frame->pinfo, Efault); + unsafe_put_user(ptr_to_compat(&frame->uc), &frame->puc, Efault); + + /* Create the ucontext. */ + if (static_cpu_has(X86_FEATURE_XSAVE)) + unsafe_put_user(UC_FP_XSTATE, &frame->uc.uc_flags, Efault); + else + unsafe_put_user(0, &frame->uc.uc_flags, Efault); + unsafe_put_user(0, &frame->uc.uc_link, Efault); + unsafe_save_altstack32(&frame->uc.uc_stack, regs->sp, Efault); + + if (ksig->ka.sa.sa_flags & SA_RESTORER) + restorer = ksig->ka.sa.sa_restorer; + else + restorer = current->mm->context.vdso + + vdso_image_32.sym___kernel_rt_sigreturn; + unsafe_put_user(ptr_to_compat(restorer), &frame->pretcode, Efault); + + /* + * Not actually used anymore, but left because some gdb + * versions need it. + */ + unsafe_put_user(*((u64 *)&code), (u64 __user *)frame->retcode, Efault); + unsafe_put_sigcontext32(&frame->uc.uc_mcontext, fp, regs, set, Efault); + unsafe_put_user(*(__u64 *)set, (__u64 __user *)&frame->uc.uc_sigmask, Efault); + user_access_end(); + + if (__copy_siginfo_to_user32(&frame->info, &ksig->info)) + return -EFAULT; + + /* Set up registers for signal handler */ + regs->sp = (unsigned long) frame; + regs->ip = (unsigned long) ksig->ka.sa.sa_handler; + + /* Make -mregparm=3 work */ + regs->ax = ksig->sig; + regs->dx = (unsigned long) &frame->info; + regs->cx = (unsigned long) &frame->uc; + +#ifdef CONFIG_IA32_EMULATION + loadsegment(ds, __USER_DS); + loadsegment(es, __USER_DS); +#else + regs->ds = __USER_DS; + regs->es = __USER_DS; +#endif + + regs->cs = __USER32_CS; + regs->ss = __USER_DS; + + return 0; +Efault: + user_access_end(); + return -EFAULT; +} + +/* + * The siginfo_t structure and handing code is very easy + * to break in several ways. It must always be updated when new + * updates are made to the main siginfo_t, and + * copy_siginfo_to_user32() must be updated when the + * (arch-independent) copy_siginfo_to_user() is updated. + * + * It is also easy to put a new member in the siginfo_t + * which has implicit alignment which can move internal structure + * alignment around breaking the ABI. This can happen if you, + * for instance, put a plain 64-bit value in there. + */ + +/* +* If adding a new si_code, there is probably new data in +* the siginfo. Make sure folks bumping the si_code +* limits also have to look at this code. Make sure any +* new fields are handled in copy_siginfo_to_user32()! +*/ +static_assert(NSIGILL == 11); +static_assert(NSIGFPE == 15); +static_assert(NSIGSEGV == 10); +static_assert(NSIGBUS == 5); +static_assert(NSIGTRAP == 6); +static_assert(NSIGCHLD == 6); +static_assert(NSIGSYS == 2); + +/* This is part of the ABI and can never change in size: */ +static_assert(sizeof(siginfo32_t) == 128); + +/* This is a part of the ABI and can never change in alignment */ +static_assert(__alignof__(siginfo32_t) == 4); + +/* +* The offsets of all the (unioned) si_fields are fixed +* in the ABI, of course. Make sure none of them ever +* move and are always at the beginning: +*/ +static_assert(offsetof(siginfo32_t, _sifields) == 3 * sizeof(int)); + +static_assert(offsetof(siginfo32_t, si_signo) == 0); +static_assert(offsetof(siginfo32_t, si_errno) == 4); +static_assert(offsetof(siginfo32_t, si_code) == 8); + +/* +* Ensure that the size of each si_field never changes. +* If it does, it is a sign that the +* copy_siginfo_to_user32() code below needs to updated +* along with the size in the CHECK_SI_SIZE(). +* +* We repeat this check for both the generic and compat +* siginfos. +* +* Note: it is OK for these to grow as long as the whole +* structure stays within the padding size (checked +* above). +*/ + +#define CHECK_SI_OFFSET(name) \ + static_assert(offsetof(siginfo32_t, _sifields) == \ + offsetof(siginfo32_t, _sifields.name)) + +#define CHECK_SI_SIZE(name, size) \ + static_assert(sizeof_field(siginfo32_t, _sifields.name) == size) + +CHECK_SI_OFFSET(_kill); +CHECK_SI_SIZE (_kill, 2*sizeof(int)); +static_assert(offsetof(siginfo32_t, si_pid) == 0xC); +static_assert(offsetof(siginfo32_t, si_uid) == 0x10); + +CHECK_SI_OFFSET(_timer); +#ifdef CONFIG_COMPAT +/* compat_siginfo_t doesn't have si_sys_private */ +CHECK_SI_SIZE (_timer, 3*sizeof(int)); +#else +CHECK_SI_SIZE (_timer, 4*sizeof(int)); +#endif +static_assert(offsetof(siginfo32_t, si_tid) == 0x0C); +static_assert(offsetof(siginfo32_t, si_overrun) == 0x10); +static_assert(offsetof(siginfo32_t, si_value) == 0x14); + +CHECK_SI_OFFSET(_rt); +CHECK_SI_SIZE (_rt, 3*sizeof(int)); +static_assert(offsetof(siginfo32_t, si_pid) == 0x0C); +static_assert(offsetof(siginfo32_t, si_uid) == 0x10); +static_assert(offsetof(siginfo32_t, si_value) == 0x14); + +CHECK_SI_OFFSET(_sigchld); +CHECK_SI_SIZE (_sigchld, 5*sizeof(int)); +static_assert(offsetof(siginfo32_t, si_pid) == 0x0C); +static_assert(offsetof(siginfo32_t, si_uid) == 0x10); +static_assert(offsetof(siginfo32_t, si_status) == 0x14); +static_assert(offsetof(siginfo32_t, si_utime) == 0x18); +static_assert(offsetof(siginfo32_t, si_stime) == 0x1C); + +CHECK_SI_OFFSET(_sigfault); +CHECK_SI_SIZE (_sigfault, 4*sizeof(int)); +static_assert(offsetof(siginfo32_t, si_addr) == 0x0C); + +static_assert(offsetof(siginfo32_t, si_trapno) == 0x10); + +static_assert(offsetof(siginfo32_t, si_addr_lsb) == 0x10); + +static_assert(offsetof(siginfo32_t, si_lower) == 0x14); +static_assert(offsetof(siginfo32_t, si_upper) == 0x18); + +static_assert(offsetof(siginfo32_t, si_pkey) == 0x14); + +static_assert(offsetof(siginfo32_t, si_perf_data) == 0x10); +static_assert(offsetof(siginfo32_t, si_perf_type) == 0x14); +static_assert(offsetof(siginfo32_t, si_perf_flags) == 0x18); + +CHECK_SI_OFFSET(_sigpoll); +CHECK_SI_SIZE (_sigpoll, 2*sizeof(int)); +static_assert(offsetof(siginfo32_t, si_band) == 0x0C); +static_assert(offsetof(siginfo32_t, si_fd) == 0x10); + +CHECK_SI_OFFSET(_sigsys); +CHECK_SI_SIZE (_sigsys, 3*sizeof(int)); +static_assert(offsetof(siginfo32_t, si_call_addr) == 0x0C); +static_assert(offsetof(siginfo32_t, si_syscall) == 0x10); +static_assert(offsetof(siginfo32_t, si_arch) == 0x14); + +/* any new si_fields should be added here */ -- cgit v1.2.3