From 24e6dc35ccd825de7c71751610ff8f3295347e5b Mon Sep 17 00:00:00 2001 From: Brian Gerst Date: Mon, 6 Jun 2022 16:38:01 -0400 Subject: [PATCH] x86/signal/32: Merge native and compat 32-bit signal code There are significant differences between signal handling on 32-bit vs. 64-bit, like different structure layouts and legacy syscalls. Instead of duplicating that code for native and compat, merge both versions into one file. Signed-off-by: Brian Gerst Signed-off-by: Borislav Petkov Acked-by: "Eric W. Biederman" Link: https://lore.kernel.org/r/20220606203802.158958-8-brgerst@gmail.com Signed-off-by: Borislav Petkov --- arch/x86/ia32/Makefile | 2 - arch/x86/include/asm/segment.h | 1 + arch/x86/kernel/Makefile | 4 +- arch/x86/kernel/signal.c | 219 +----------------- .../ia32_signal.c => kernel/signal_32.c} | 59 ++++- include/linux/syscalls.h | 2 + 6 files changed, 60 insertions(+), 227 deletions(-) rename arch/x86/{ia32/ia32_signal.c => kernel/signal_32.c} (86%) diff --git a/arch/x86/ia32/Makefile b/arch/x86/ia32/Makefile index e481056698de..333556a86b2a 100644 --- a/arch/x86/ia32/Makefile +++ b/arch/x86/ia32/Makefile @@ -3,7 +3,5 @@ # Makefile for the ia32 kernel emulation subsystem. # -obj-$(CONFIG_IA32_EMULATION) := ia32_signal.o - audit-class-$(CONFIG_AUDIT) := audit.o obj-$(CONFIG_IA32_EMULATION) += $(audit-class-y) diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h index e056c29dfcda..c390a672d560 100644 --- a/arch/x86/include/asm/segment.h +++ b/arch/x86/include/asm/segment.h @@ -135,6 +135,7 @@ #define __KERNEL_DS (GDT_ENTRY_KERNEL_DS*8) #define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS*8 + 3) #define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS*8 + 3) +#define __USER32_CS __USER_CS #define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS*8) /* segment for calling fn: */ diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index f901658d9f7c..72e137199df1 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -53,8 +53,8 @@ obj-y += setup.o x86_init.o i8259.o irqinit.o obj-$(CONFIG_JUMP_LABEL) += jump_label.o obj-$(CONFIG_IRQ_WORK) += irq_work.o obj-y += probe_roms.o -obj-$(CONFIG_X86_32) += sys_ia32.o -obj-$(CONFIG_IA32_EMULATION) += sys_ia32.o +obj-$(CONFIG_X86_32) += sys_ia32.o signal_32.o +obj-$(CONFIG_IA32_EMULATION) += sys_ia32.o signal_32.o obj-$(CONFIG_X86_64) += sys_x86_64.o obj-$(CONFIG_X86_ESPFIX64) += espfix_64.o obj-$(CONFIG_SYSFS) += ksysfs.o diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 0511e050d24a..962cfd835c90 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -92,10 +92,6 @@ static void force_valid_ss(struct pt_regs *regs) ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA_EXPDOWN)) regs->ss = __USER_DS; } -# define CONTEXT_COPY_SIZE offsetof(struct sigcontext, reserved1) -#else -# define CONTEXT_COPY_SIZE sizeof(struct sigcontext) -#endif static bool restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, @@ -106,16 +102,9 @@ static bool restore_sigcontext(struct pt_regs *regs, /* Always make any pending restarted system calls return -EINTR */ current->restart_block.fn = do_no_restart_syscall; - if (copy_from_user(&sc, usc, CONTEXT_COPY_SIZE)) + if (copy_from_user(&sc, usc, offsetof(struct sigcontext, reserved1))) return false; -#ifdef CONFIG_X86_32 - loadsegment(gs, sc.gs); - regs->fs = sc.fs; - regs->es = sc.es; - regs->ds = sc.ds; -#endif /* CONFIG_X86_32 */ - regs->bx = sc.bx; regs->cx = sc.cx; regs->dx = sc.dx; @@ -125,8 +114,6 @@ static bool restore_sigcontext(struct pt_regs *regs, regs->ax = sc.ax; regs->sp = sc.sp; regs->ip = sc.ip; - -#ifdef CONFIG_X86_64 regs->r8 = sc.r8; regs->r9 = sc.r9; regs->r10 = sc.r10; @@ -135,7 +122,6 @@ static bool restore_sigcontext(struct pt_regs *regs, regs->r13 = sc.r13; regs->r14 = sc.r14; regs->r15 = sc.r15; -#endif /* CONFIG_X86_64 */ /* Get CS/SS and force CPL3 */ regs->cs = sc.cs | 0x03; @@ -145,33 +131,20 @@ static bool restore_sigcontext(struct pt_regs *regs, /* disable syscall checks */ regs->orig_ax = -1; -#ifdef CONFIG_X86_64 /* * Fix up SS if needed for the benefit of old DOSEMU and * CRIU. */ if (unlikely(!(uc_flags & UC_STRICT_RESTORE_SS) && user_64bit_mode(regs))) force_valid_ss(regs); -#endif - return fpu__restore_sig((void __user *)sc.fpstate, - IS_ENABLED(CONFIG_X86_32)); + return fpu__restore_sig((void __user *)sc.fpstate, 0); } static __always_inline int __unsafe_setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate, struct pt_regs *regs, unsigned long mask) { -#ifdef CONFIG_X86_32 - unsigned int gs; - savesegment(gs, gs); - - unsafe_put_user(gs, (unsigned int __user *)&sc->gs, Efault); - 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 /* CONFIG_X86_32 */ - unsafe_put_user(regs->di, &sc->di, Efault); unsafe_put_user(regs->si, &sc->si, Efault); unsafe_put_user(regs->bp, &sc->bp, Efault); @@ -180,7 +153,6 @@ __unsafe_setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate, unsafe_put_user(regs->dx, &sc->dx, Efault); unsafe_put_user(regs->cx, &sc->cx, Efault); unsafe_put_user(regs->ax, &sc->ax, Efault); -#ifdef CONFIG_X86_64 unsafe_put_user(regs->r8, &sc->r8, Efault); unsafe_put_user(regs->r9, &sc->r9, Efault); unsafe_put_user(regs->r10, &sc->r10, Efault); @@ -189,23 +161,15 @@ __unsafe_setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate, unsafe_put_user(regs->r13, &sc->r13, Efault); unsafe_put_user(regs->r14, &sc->r14, Efault); unsafe_put_user(regs->r15, &sc->r15, Efault); -#endif /* CONFIG_X86_64 */ 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); -#ifdef CONFIG_X86_32 - 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); -#else /* !CONFIG_X86_32 */ unsafe_put_user(regs->flags, &sc->flags, Efault); unsafe_put_user(regs->cs, &sc->cs, Efault); unsafe_put_user(0, &sc->gs, Efault); unsafe_put_user(0, &sc->fs, Efault); unsafe_put_user(regs->ss, &sc->ss, Efault); -#endif /* CONFIG_X86_32 */ unsafe_put_user(fpstate, (unsigned long __user *)&sc->fpstate, Efault); @@ -228,6 +192,8 @@ do { \ (__u64 __user *)&(frame)->uc.uc_sigmask, \ label) +#endif /* CONFIG_X86_64 */ + /* * Set up a signal frame. */ @@ -313,148 +279,7 @@ get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size, return (void __user *)sp; } -#ifdef CONFIG_X86_32 -static const struct { - u16 poplmovl; - u32 val; - u16 int80; -} __attribute__((packed)) retcode = { - 0xb858, /* popl %eax; movl $..., %eax */ - __NR_sigreturn, - 0x80cd, /* int $0x80 */ -}; - -static const struct { - u8 movl; - u32 val; - u16 int80; - u8 pad; -} __attribute__((packed)) rt_retcode = { - 0xb8, /* movl $..., %eax */ - __NR_rt_sigreturn, - 0x80cd, /* int $0x80 */ - 0 -}; - -int ia32_setup_frame(struct ksignal *ksig, struct pt_regs *regs) -{ - sigset_t *set = sigmask_to_save(); - struct sigframe __user *frame; - void __user *restorer; - void __user *fp = NULL; - - 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_sigcontext(&frame->sc, fp, regs, set, Efault); - unsafe_put_user(set->sig[1], &frame->extramask[0], Efault); - if (current->mm->context.vdso) - restorer = current->mm->context.vdso + - vdso_image_32.sym___kernel_sigreturn; - else - restorer = &frame->retcode; - if (ksig->ka.sa.sa_flags & SA_RESTORER) - restorer = ksig->ka.sa.sa_restorer; - - /* Set up to return from userspace. */ - unsafe_put_user(restorer, &frame->pretcode, Efault); - - /* - * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80 - * - * WE DO NOT USE IT ANY MORE! It's only left here for historical - * reasons and because gdb uses it as a signature to notice - * signal handler stack frames. - */ - unsafe_put_user(*((u64 *)&retcode), (u64 *)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; - regs->ax = (unsigned long)ksig->sig; - regs->dx = 0; - regs->cx = 0; - - regs->ds = __USER_DS; - regs->es = __USER_DS; - regs->ss = __USER_DS; - regs->cs = __USER_CS; - - return 0; - -Efault: - user_access_end(); - return -EFAULT; -} - -int ia32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) -{ - sigset_t *set = sigmask_to_save(); - struct rt_sigframe __user *frame; - void __user *restorer; - void __user *fp = NULL; - - 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(&frame->info, &frame->pinfo, Efault); - unsafe_put_user(&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_altstack(&frame->uc.uc_stack, regs->sp, Efault); - - /* Set up to return from userspace. */ - restorer = current->mm->context.vdso + - vdso_image_32.sym___kernel_rt_sigreturn; - if (ksig->ka.sa.sa_flags & SA_RESTORER) - restorer = ksig->ka.sa.sa_restorer; - unsafe_put_user(restorer, &frame->pretcode, Efault); - - /* - * This is movl $__NR_rt_sigreturn, %ax ; int $0x80 - * - * WE DO NOT USE IT ANY MORE! It's only left here for historical - * reasons and because gdb uses it as a signature to notice - * signal handler stack frames. - */ - unsafe_put_user(*((u64 *)&rt_retcode), (u64 *)frame->retcode, Efault); - unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault); - unsafe_put_sigmask(set, frame, Efault); - user_access_end(); - - if (copy_siginfo_to_user(&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; - regs->ax = (unsigned long)ksig->sig; - regs->dx = (unsigned long)&frame->info; - regs->cx = (unsigned long)&frame->uc; - - regs->ds = __USER_DS; - regs->es = __USER_DS; - regs->ss = __USER_DS; - regs->cs = __USER_CS; - - return 0; -Efault: - user_access_end(); - return -EFAULT; -} -#else /* !CONFIG_X86_32 */ +#ifdef CONFIG_X86_64 static unsigned long frame_uc_flags(struct pt_regs *regs) { unsigned long flags; @@ -545,7 +370,6 @@ Efault: user_access_end(); return -EFAULT; } -#endif /* CONFIG_X86_32 */ #ifdef CONFIG_X86_X32_ABI static int x32_copy_siginfo_to_user(struct compat_siginfo __user *to, @@ -631,38 +455,6 @@ Efault: /* * Do a signal return; undo the signal stack. */ -#ifdef CONFIG_X86_32 -SYSCALL_DEFINE0(sigreturn) -{ - struct pt_regs *regs = current_pt_regs(); - struct sigframe __user *frame; - sigset_t set; - - frame = (struct sigframe __user *)(regs->sp - 8); - - if (!access_ok(frame, sizeof(*frame))) - goto badframe; - if (__get_user(set.sig[0], &frame->sc.oldmask) || - __get_user(set.sig[1], &frame->extramask[0])) - goto badframe; - - set_current_blocked(&set); - - /* - * x86_32 has no uc_flags bits relevant to restore_sigcontext. - * Save a few cycles by skipping the __get_user. - */ - if (!restore_sigcontext(regs, &frame->sc, 0)) - goto badframe; - return regs->ax; - -badframe: - signal_fault(regs, frame, "sigreturn"); - - return 0; -} -#endif /* CONFIG_X86_32 */ - SYSCALL_DEFINE0(rt_sigreturn) { struct pt_regs *regs = current_pt_regs(); @@ -692,6 +484,7 @@ badframe: signal_fault(regs, frame, "rt_sigreturn"); return 0; } +#endif /* CONFIG_X86_64 */ /* * There are four different struct types for signal frame: sigframe_ia32, diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/kernel/signal_32.c similarity index 86% rename from arch/x86/ia32/ia32_signal.c rename to arch/x86/kernel/signal_32.c index e28421f53d44..2553136cf39b 100644 --- a/arch/x86/ia32/ia32_signal.c +++ b/arch/x86/kernel/signal_32.c @@ -1,7 +1,5 @@ // SPDX-License-Identifier: GPL-2.0 /* - * linux/arch/x86_64/ia32/ia32_signal.c - * * Copyright (C) 1991, 1992 Linus Torvalds * * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson @@ -26,7 +24,6 @@ #include #include #include -#include #include #include #include @@ -35,6 +32,9 @@ #include #include +#ifdef CONFIG_IA32_EMULATION +#include + static inline void reload_segments(struct sigcontext_32 *sc) { unsigned int cur; @@ -53,6 +53,21 @@ static inline void reload_segments(struct sigcontext_32 *sc) loadsegment(es, sc->es | 0x03); } +#define sigset32_t compat_sigset_t +#define restore_altstack32 compat_restore_altstack +#define unsafe_save_altstack32 unsafe_compat_save_altstack + +#else + +#define sigset32_t sigset_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. */ @@ -86,6 +101,7 @@ static bool ia32_restore_sigcontext(struct pt_regs *regs, /* 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 @@ -93,10 +109,17 @@ static bool ia32_restore_sigcontext(struct pt_regs *regs, * 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); } -COMPAT_SYSCALL_DEFINE0(sigreturn) +SYSCALL32_DEFINE0(sigreturn) { struct pt_regs *regs = current_pt_regs(); struct sigframe_ia32 __user *frame = (struct sigframe_ia32 __user *)(regs->sp-8); @@ -119,7 +142,7 @@ badframe: return 0; } -COMPAT_SYSCALL_DEFINE0(rt_sigreturn) +SYSCALL32_DEFINE0(rt_sigreturn) { struct pt_regs *regs = current_pt_regs(); struct rt_sigframe_ia32 __user *frame; @@ -129,7 +152,7 @@ COMPAT_SYSCALL_DEFINE0(rt_sigreturn) if (!access_ok(frame, sizeof(*frame))) goto badframe; - if (__get_user(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask)) + if (__get_user(*(__u64 *)&set, (__u64 __user *)&frame->uc.uc_sigmask)) goto badframe; set_current_blocked(&set); @@ -137,7 +160,7 @@ COMPAT_SYSCALL_DEFINE0(rt_sigreturn) if (!ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext)) goto badframe; - if (compat_restore_altstack(&frame->uc.uc_stack)) + if (restore_altstack32(&frame->uc.uc_stack)) goto badframe; return regs->ax; @@ -159,9 +182,15 @@ __unsafe_setup_sigcontext32(struct sigcontext_32 __user *sc, 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); @@ -198,7 +227,7 @@ do { \ int ia32_setup_frame(struct ksignal *ksig, struct pt_regs *regs) { - compat_sigset_t *set = (compat_sigset_t *) sigmask_to_save(); + sigset32_t *set = (sigset32_t *) sigmask_to_save(); struct sigframe_ia32 __user *frame; void __user *restorer; void __user *fp = NULL; @@ -250,8 +279,13 @@ int ia32_setup_frame(struct ksignal *ksig, struct pt_regs *regs) 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; @@ -264,7 +298,7 @@ Efault: int ia32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) { - compat_sigset_t *set = (compat_sigset_t *) sigmask_to_save(); + sigset32_t *set = (sigset32_t *) sigmask_to_save(); struct rt_sigframe_ia32 __user *frame; void __user *restorer; void __user *fp = NULL; @@ -297,7 +331,7 @@ int ia32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) else unsafe_put_user(0, &frame->uc.uc_flags, Efault); unsafe_put_user(0, &frame->uc.uc_link, Efault); - unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->sp, 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; @@ -327,8 +361,13 @@ int ia32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) 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; diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index a34b0f9a9972..33a0ee3bcb2e 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -264,6 +264,7 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event) #define SC_VAL64(type, name) ((type) name##_hi << 32 | name##_lo) #ifdef CONFIG_COMPAT +#define SYSCALL32_DEFINE0 COMPAT_SYSCALL_DEFINE0 #define SYSCALL32_DEFINE1 COMPAT_SYSCALL_DEFINE1 #define SYSCALL32_DEFINE2 COMPAT_SYSCALL_DEFINE2 #define SYSCALL32_DEFINE3 COMPAT_SYSCALL_DEFINE3 @@ -271,6 +272,7 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event) #define SYSCALL32_DEFINE5 COMPAT_SYSCALL_DEFINE5 #define SYSCALL32_DEFINE6 COMPAT_SYSCALL_DEFINE6 #else +#define SYSCALL32_DEFINE0 SYSCALL_DEFINE0 #define SYSCALL32_DEFINE1 SYSCALL_DEFINE1 #define SYSCALL32_DEFINE2 SYSCALL_DEFINE2 #define SYSCALL32_DEFINE3 SYSCALL_DEFINE3