3 files changed, 431 insertions, 0 deletions
diff --git a/arch/x86/ia32/Makefile b/arch/x86/ia32/Makefile
new file mode 100644
index 000000000..e48105669
--- /dev/null
+++ b/arch/x86/ia32/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# 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/ia32/audit.c b/arch/x86/ia32/audit.c
new file mode 100644
index 000000000..59e19549e
--- /dev/null
+++ b/arch/x86/ia32/audit.c
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/audit_arch.h>
+#include <asm/unistd_32.h>
+#include <asm/audit.h>
+
+unsigned ia32_dir_class[] = {
+#include <asm-generic/audit_dir_write.h>
+~0U
+};
+
+unsigned ia32_chattr_class[] = {
+#include <asm-generic/audit_change_attr.h>
+~0U
+};
+
+unsigned ia32_write_class[] = {
+#include <asm-generic/audit_write.h>
+~0U
+};
+
+unsigned ia32_read_class[] = {
+#include <asm-generic/audit_read.h>
+~0U
+};
+
+unsigned ia32_signal_class[] = {
+#include <asm-generic/audit_signal.h>
+~0U
+};
+
+int ia32_classify_syscall(unsigned syscall)
+{
+	switch (syscall) {
+	case __NR_open:
+		return AUDITSC_OPEN;
+	case __NR_openat:
+		return AUDITSC_OPENAT;
+	case __NR_socketcall:
+		return AUDITSC_SOCKETCALL;
+	case __NR_execve:
+	case __NR_execveat:
+		return AUDITSC_EXECVE;
+	case __NR_openat2:
+		return AUDITSC_OPENAT2;
+	default:
+		return AUDITSC_COMPAT;
+	}
+}
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
new file mode 100644
index 000000000..c9c385932
--- /dev/null
+++ b/arch/x86/ia32/ia32_signal.c
@@ -0,0 +1,374 @@
+// 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
+ *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
+ *  2000-12-*   x86-64 compatibility mode signal handling by Andi Kleen
+ */
+
+#include <linux/sched.h>
+#include <linux/sched/task_stack.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/wait.h>
+#include <linux/unistd.h>
+#include <linux/stddef.h>
+#include <linux/personality.h>
+#include <linux/compat.h>
+#include <linux/binfmts.h>
+#include <linux/syscalls.h>
+#include <asm/ucontext.h>
+#include <linux/uaccess.h>
+#include <asm/fpu/signal.h>
+#include <asm/ptrace.h>
+#include <asm/ia32_unistd.h>
+#include <asm/user32.h>
+#include <uapi/asm/sigcontext.h>
+#include <asm/proto.h>
+#include <asm/vdso.h>
+#include <asm/sigframe.h>
+#include <asm/sighandling.h>
+#include <asm/smap.h>
+
+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);
+}
+
+/*
+ * 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;
+
+	/*
+	 * 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);
+	return fpu__restore_sig(compat_ptr(sc.fpstate), 1);
+}
+
+COMPAT_SYSCALL_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;
+}
+
+COMPAT_SYSCALL_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(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask))
+		goto badframe;
+
+	set_current_blocked(&set);
+
+	if (!ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext))
+		goto badframe;
+
+	if (compat_restore_altstack(&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);
+	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);
+
+	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)
+
+/*
+ * Determine which stack to use..
+ */
+static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
+				 size_t frame_size,
+				 void __user **fpstate)
+{
+	unsigned long sp, fx_aligned, math_size;
+
+	/* Default to using normal stack */
+	sp = regs->sp;
+
+	/* This is the X/Open sanctioned signal stack switching.  */
+	if (ksig->ka.sa.sa_flags & SA_ONSTACK)
+		sp = sigsp(sp, ksig);
+	/* This is the legacy signal stack switching. */
+	else if (regs->ss != __USER32_DS &&
+		!(ksig->ka.sa.sa_flags & SA_RESTORER) &&
+		 ksig->ka.sa.sa_restorer)
+		sp = (unsigned long) ksig->ka.sa.sa_restorer;
+
+	sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size);
+	*fpstate = (struct _fpstate_32 __user *) sp;
+	if (!copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned,
+				      math_size))
+		return (void __user *) -1L;
+
+	sp -= frame_size;
+	/* Align the stack pointer according to the i386 ABI,
+	 * i.e. so that on function entry ((sp + 4) & 15) == 0. */
+	sp = ((sp + 4) & -16ul) - 4;
+	return (void __user *) sp;
+}
+
+int ia32_setup_frame(int sig, struct ksignal *ksig,
+		     compat_sigset_t *set, struct pt_regs *regs)
+{
+	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(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 = sig;
+	regs->dx = 0;
+	regs->cx = 0;
+
+	loadsegment(ds, __USER32_DS);
+	loadsegment(es, __USER32_DS);
+
+	regs->cs = __USER32_CS;
+	regs->ss = __USER32_DS;
+
+	return 0;
+Efault:
+	user_access_end();
+	return -EFAULT;
+}
+
+int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
+			compat_sigset_t *set, struct pt_regs *regs)
+{
+	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(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_compat_save_altstack(&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 = sig;
+	regs->dx = (unsigned long) &frame->info;
+	regs->cx = (unsigned long) &frame->uc;
+
+	loadsegment(ds, __USER32_DS);
+	loadsegment(es, __USER32_DS);
+
+	regs->cs = __USER32_CS;
+	regs->ss = __USER32_DS;
+
+	return 0;
+Efault:
+	user_access_end();
+	return -EFAULT;
+}