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-rw-r--r--arch/x86/kernel/signal.c878
1 files changed, 878 insertions, 0 deletions
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
new file mode 100644
index 000000000..16e908000
--- /dev/null
+++ b/arch/x86/kernel/signal.c
@@ -0,0 +1,878 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ * Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
+ *
+ * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
+ * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
+ * 2000-2002 x86-64 support by Andi Kleen
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#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/tracehook.h>
+#include <linux/unistd.h>
+#include <linux/stddef.h>
+#include <linux/personality.h>
+#include <linux/uaccess.h>
+#include <linux/user-return-notifier.h>
+#include <linux/uprobes.h>
+#include <linux/context_tracking.h>
+#include <linux/syscalls.h>
+
+#include <asm/processor.h>
+#include <asm/ucontext.h>
+#include <asm/fpu/internal.h>
+#include <asm/fpu/signal.h>
+#include <asm/vdso.h>
+#include <asm/mce.h>
+#include <asm/sighandling.h>
+#include <asm/vm86.h>
+
+#ifdef CONFIG_X86_64
+#include <asm/proto.h>
+#include <asm/ia32_unistd.h>
+#endif /* CONFIG_X86_64 */
+
+#include <asm/syscall.h>
+#include <asm/syscalls.h>
+
+#include <asm/sigframe.h>
+#include <asm/signal.h>
+
+#define COPY(x) do { \
+ get_user_ex(regs->x, &sc->x); \
+} while (0)
+
+#define GET_SEG(seg) ({ \
+ unsigned short tmp; \
+ get_user_ex(tmp, &sc->seg); \
+ tmp; \
+})
+
+#define COPY_SEG(seg) do { \
+ regs->seg = GET_SEG(seg); \
+} while (0)
+
+#define COPY_SEG_CPL3(seg) do { \
+ regs->seg = GET_SEG(seg) | 3; \
+} while (0)
+
+#ifdef CONFIG_X86_64
+/*
+ * If regs->ss will cause an IRET fault, change it. Otherwise leave it
+ * alone. Using this generally makes no sense unless
+ * user_64bit_mode(regs) would return true.
+ */
+static void force_valid_ss(struct pt_regs *regs)
+{
+ u32 ar;
+ asm volatile ("lar %[old_ss], %[ar]\n\t"
+ "jz 1f\n\t" /* If invalid: */
+ "xorl %[ar], %[ar]\n\t" /* set ar = 0 */
+ "1:"
+ : [ar] "=r" (ar)
+ : [old_ss] "rm" ((u16)regs->ss));
+
+ /*
+ * For a valid 64-bit user context, we need DPL 3, type
+ * read-write data or read-write exp-down data, and S and P
+ * set. We can't use VERW because VERW doesn't check the
+ * P bit.
+ */
+ ar &= AR_DPL_MASK | AR_S | AR_P | AR_TYPE_MASK;
+ if (ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA) &&
+ ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA_EXPDOWN))
+ regs->ss = __USER_DS;
+}
+#endif
+
+static int restore_sigcontext(struct pt_regs *regs,
+ struct sigcontext __user *sc,
+ unsigned long uc_flags)
+{
+ unsigned long buf_val;
+ void __user *buf;
+ unsigned int tmpflags;
+ unsigned int err = 0;
+
+ /* Always make any pending restarted system calls return -EINTR */
+ current->restart_block.fn = do_no_restart_syscall;
+
+ get_user_try {
+
+#ifdef CONFIG_X86_32
+ set_user_gs(regs, GET_SEG(gs));
+ COPY_SEG(fs);
+ COPY_SEG(es);
+ COPY_SEG(ds);
+#endif /* CONFIG_X86_32 */
+
+ COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
+ COPY(dx); COPY(cx); COPY(ip); COPY(ax);
+
+#ifdef CONFIG_X86_64
+ COPY(r8);
+ COPY(r9);
+ COPY(r10);
+ COPY(r11);
+ COPY(r12);
+ COPY(r13);
+ COPY(r14);
+ COPY(r15);
+#endif /* CONFIG_X86_64 */
+
+ COPY_SEG_CPL3(cs);
+ COPY_SEG_CPL3(ss);
+
+ get_user_ex(tmpflags, &sc->flags);
+ regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
+ regs->orig_ax = -1; /* disable syscall checks */
+
+ get_user_ex(buf_val, &sc->fpstate);
+ buf = (void __user *)buf_val;
+ } get_user_catch(err);
+
+#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
+
+ err |= fpu__restore_sig(buf, IS_ENABLED(CONFIG_X86_32));
+
+ force_iret();
+
+ return err;
+}
+
+int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
+ struct pt_regs *regs, unsigned long mask)
+{
+ int err = 0;
+
+ put_user_try {
+
+#ifdef CONFIG_X86_32
+ put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
+ put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
+ put_user_ex(regs->es, (unsigned int __user *)&sc->es);
+ put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
+#endif /* CONFIG_X86_32 */
+
+ put_user_ex(regs->di, &sc->di);
+ put_user_ex(regs->si, &sc->si);
+ put_user_ex(regs->bp, &sc->bp);
+ put_user_ex(regs->sp, &sc->sp);
+ put_user_ex(regs->bx, &sc->bx);
+ put_user_ex(regs->dx, &sc->dx);
+ put_user_ex(regs->cx, &sc->cx);
+ put_user_ex(regs->ax, &sc->ax);
+#ifdef CONFIG_X86_64
+ put_user_ex(regs->r8, &sc->r8);
+ put_user_ex(regs->r9, &sc->r9);
+ put_user_ex(regs->r10, &sc->r10);
+ put_user_ex(regs->r11, &sc->r11);
+ put_user_ex(regs->r12, &sc->r12);
+ put_user_ex(regs->r13, &sc->r13);
+ put_user_ex(regs->r14, &sc->r14);
+ put_user_ex(regs->r15, &sc->r15);
+#endif /* CONFIG_X86_64 */
+
+ put_user_ex(current->thread.trap_nr, &sc->trapno);
+ put_user_ex(current->thread.error_code, &sc->err);
+ put_user_ex(regs->ip, &sc->ip);
+#ifdef CONFIG_X86_32
+ put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
+ put_user_ex(regs->flags, &sc->flags);
+ put_user_ex(regs->sp, &sc->sp_at_signal);
+ put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
+#else /* !CONFIG_X86_32 */
+ put_user_ex(regs->flags, &sc->flags);
+ put_user_ex(regs->cs, &sc->cs);
+ put_user_ex(0, &sc->gs);
+ put_user_ex(0, &sc->fs);
+ put_user_ex(regs->ss, &sc->ss);
+#endif /* CONFIG_X86_32 */
+
+ put_user_ex(fpstate, &sc->fpstate);
+
+ /* non-iBCS2 extensions.. */
+ put_user_ex(mask, &sc->oldmask);
+ put_user_ex(current->thread.cr2, &sc->cr2);
+ } put_user_catch(err);
+
+ return err;
+}
+
+/*
+ * Set up a signal frame.
+ */
+
+/*
+ * Determine which stack to use..
+ */
+static unsigned long align_sigframe(unsigned long sp)
+{
+#ifdef CONFIG_X86_32
+ /*
+ * 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;
+#else /* !CONFIG_X86_32 */
+ sp = round_down(sp, 16) - 8;
+#endif
+ return sp;
+}
+
+static void __user *
+get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
+ void __user **fpstate)
+{
+ /* Default to using normal stack */
+ unsigned long math_size = 0;
+ unsigned long sp = regs->sp;
+ unsigned long buf_fx = 0;
+ int onsigstack = on_sig_stack(sp);
+ struct fpu *fpu = &current->thread.fpu;
+
+ /* redzone */
+ if (IS_ENABLED(CONFIG_X86_64))
+ sp -= 128;
+
+ /* This is the X/Open sanctioned signal stack switching. */
+ if (ka->sa.sa_flags & SA_ONSTACK) {
+ if (sas_ss_flags(sp) == 0)
+ sp = current->sas_ss_sp + current->sas_ss_size;
+ } else if (IS_ENABLED(CONFIG_X86_32) &&
+ !onsigstack &&
+ regs->ss != __USER_DS &&
+ !(ka->sa.sa_flags & SA_RESTORER) &&
+ ka->sa.sa_restorer) {
+ /* This is the legacy signal stack switching. */
+ sp = (unsigned long) ka->sa.sa_restorer;
+ }
+
+ if (fpu->initialized) {
+ sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32),
+ &buf_fx, &math_size);
+ *fpstate = (void __user *)sp;
+ }
+
+ sp = align_sigframe(sp - frame_size);
+
+ /*
+ * If we are on the alternate signal stack and would overflow it, don't.
+ * Return an always-bogus address instead so we will die with SIGSEGV.
+ */
+ if (onsigstack && !likely(on_sig_stack(sp)))
+ return (void __user *)-1L;
+
+ /* save i387 and extended state */
+ if (fpu->initialized &&
+ copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size) < 0)
+ return (void __user *)-1L;
+
+ 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
+};
+
+static int
+__setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
+ struct pt_regs *regs)
+{
+ struct sigframe __user *frame;
+ void __user *restorer;
+ int err = 0;
+ void __user *fpstate = NULL;
+
+ frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
+
+ if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+ return -EFAULT;
+
+ if (__put_user(sig, &frame->sig))
+ return -EFAULT;
+
+ if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
+ return -EFAULT;
+
+ if (_NSIG_WORDS > 1) {
+ if (__copy_to_user(&frame->extramask, &set->sig[1],
+ sizeof(frame->extramask)))
+ return -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. */
+ err |= __put_user(restorer, &frame->pretcode);
+
+ /*
+ * 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.
+ */
+ err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
+
+ if (err)
+ 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)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;
+}
+
+static int __setup_rt_frame(int sig, struct ksignal *ksig,
+ sigset_t *set, struct pt_regs *regs)
+{
+ struct rt_sigframe __user *frame;
+ void __user *restorer;
+ int err = 0;
+ void __user *fpstate = NULL;
+
+ frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
+
+ if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+ return -EFAULT;
+
+ put_user_try {
+ put_user_ex(sig, &frame->sig);
+ put_user_ex(&frame->info, &frame->pinfo);
+ put_user_ex(&frame->uc, &frame->puc);
+
+ /* Create the ucontext. */
+ if (boot_cpu_has(X86_FEATURE_XSAVE))
+ put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
+ else
+ put_user_ex(0, &frame->uc.uc_flags);
+ put_user_ex(0, &frame->uc.uc_link);
+ save_altstack_ex(&frame->uc.uc_stack, regs->sp);
+
+ /* 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;
+ put_user_ex(restorer, &frame->pretcode);
+
+ /*
+ * 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.
+ */
+ put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
+ } put_user_catch(err);
+
+ err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+ err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
+ regs, set->sig[0]);
+ err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+
+ if (err)
+ 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)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;
+}
+#else /* !CONFIG_X86_32 */
+static unsigned long frame_uc_flags(struct pt_regs *regs)
+{
+ unsigned long flags;
+
+ if (boot_cpu_has(X86_FEATURE_XSAVE))
+ flags = UC_FP_XSTATE | UC_SIGCONTEXT_SS;
+ else
+ flags = UC_SIGCONTEXT_SS;
+
+ if (likely(user_64bit_mode(regs)))
+ flags |= UC_STRICT_RESTORE_SS;
+
+ return flags;
+}
+
+static int __setup_rt_frame(int sig, struct ksignal *ksig,
+ sigset_t *set, struct pt_regs *regs)
+{
+ struct rt_sigframe __user *frame;
+ void __user *fp = NULL;
+ unsigned long uc_flags;
+ int err = 0;
+
+ frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);
+
+ if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+ return -EFAULT;
+
+ if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
+ if (copy_siginfo_to_user(&frame->info, &ksig->info))
+ return -EFAULT;
+ }
+
+ uc_flags = frame_uc_flags(regs);
+
+ put_user_try {
+ /* Create the ucontext. */
+ put_user_ex(uc_flags, &frame->uc.uc_flags);
+ put_user_ex(0, &frame->uc.uc_link);
+ save_altstack_ex(&frame->uc.uc_stack, regs->sp);
+
+ /* Set up to return from userspace. If provided, use a stub
+ already in userspace. */
+ /* x86-64 should always use SA_RESTORER. */
+ if (ksig->ka.sa.sa_flags & SA_RESTORER) {
+ put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode);
+ } else {
+ /* could use a vstub here */
+ err |= -EFAULT;
+ }
+ } put_user_catch(err);
+
+ err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
+ err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+
+ if (err)
+ return -EFAULT;
+
+ /* Set up registers for signal handler */
+ regs->di = sig;
+ /* In case the signal handler was declared without prototypes */
+ regs->ax = 0;
+
+ /* This also works for non SA_SIGINFO handlers because they expect the
+ next argument after the signal number on the stack. */
+ regs->si = (unsigned long)&frame->info;
+ regs->dx = (unsigned long)&frame->uc;
+ regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
+
+ regs->sp = (unsigned long)frame;
+
+ /*
+ * Set up the CS and SS registers to run signal handlers in
+ * 64-bit mode, even if the handler happens to be interrupting
+ * 32-bit or 16-bit code.
+ *
+ * SS is subtle. In 64-bit mode, we don't need any particular
+ * SS descriptor, but we do need SS to be valid. It's possible
+ * that the old SS is entirely bogus -- this can happen if the
+ * signal we're trying to deliver is #GP or #SS caused by a bad
+ * SS value. We also have a compatbility issue here: DOSEMU
+ * relies on the contents of the SS register indicating the
+ * SS value at the time of the signal, even though that code in
+ * DOSEMU predates sigreturn's ability to restore SS. (DOSEMU
+ * avoids relying on sigreturn to restore SS; instead it uses
+ * a trampoline.) So we do our best: if the old SS was valid,
+ * we keep it. Otherwise we replace it.
+ */
+ regs->cs = __USER_CS;
+
+ if (unlikely(regs->ss != __USER_DS))
+ force_valid_ss(regs);
+
+ return 0;
+}
+#endif /* CONFIG_X86_32 */
+
+static int x32_setup_rt_frame(struct ksignal *ksig,
+ compat_sigset_t *set,
+ struct pt_regs *regs)
+{
+#ifdef CONFIG_X86_X32_ABI
+ struct rt_sigframe_x32 __user *frame;
+ unsigned long uc_flags;
+ void __user *restorer;
+ int err = 0;
+ void __user *fpstate = NULL;
+
+ frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
+
+ if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+ return -EFAULT;
+
+ if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
+ if (__copy_siginfo_to_user32(&frame->info, &ksig->info, true))
+ return -EFAULT;
+ }
+
+ uc_flags = frame_uc_flags(regs);
+
+ put_user_try {
+ /* Create the ucontext. */
+ put_user_ex(uc_flags, &frame->uc.uc_flags);
+ put_user_ex(0, &frame->uc.uc_link);
+ compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
+ put_user_ex(0, &frame->uc.uc__pad0);
+
+ if (ksig->ka.sa.sa_flags & SA_RESTORER) {
+ restorer = ksig->ka.sa.sa_restorer;
+ } else {
+ /* could use a vstub here */
+ restorer = NULL;
+ err |= -EFAULT;
+ }
+ put_user_ex(restorer, &frame->pretcode);
+ } put_user_catch(err);
+
+ err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
+ regs, set->sig[0]);
+ err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+
+ if (err)
+ return -EFAULT;
+
+ /* Set up registers for signal handler */
+ regs->sp = (unsigned long) frame;
+ regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
+
+ /* We use the x32 calling convention here... */
+ regs->di = ksig->sig;
+ regs->si = (unsigned long) &frame->info;
+ regs->dx = (unsigned long) &frame->uc;
+
+ loadsegment(ds, __USER_DS);
+ loadsegment(es, __USER_DS);
+
+ regs->cs = __USER_CS;
+ regs->ss = __USER_DS;
+#endif /* CONFIG_X86_X32_ABI */
+
+ return 0;
+}
+
+/*
+ * 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(VERIFY_READ, frame, sizeof(*frame)))
+ goto badframe;
+ if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
+ && __copy_from_user(&set.sig[1], &frame->extramask,
+ sizeof(frame->extramask))))
+ 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();
+ struct rt_sigframe __user *frame;
+ sigset_t set;
+ unsigned long uc_flags;
+
+ frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
+ if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
+ goto badframe;
+ if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+ goto badframe;
+ if (__get_user(uc_flags, &frame->uc.uc_flags))
+ goto badframe;
+
+ set_current_blocked(&set);
+
+ if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags))
+ goto badframe;
+
+ if (restore_altstack(&frame->uc.uc_stack))
+ goto badframe;
+
+ return regs->ax;
+
+badframe:
+ signal_fault(regs, frame, "rt_sigreturn");
+ return 0;
+}
+
+static inline int is_ia32_compat_frame(struct ksignal *ksig)
+{
+ return IS_ENABLED(CONFIG_IA32_EMULATION) &&
+ ksig->ka.sa.sa_flags & SA_IA32_ABI;
+}
+
+static inline int is_ia32_frame(struct ksignal *ksig)
+{
+ return IS_ENABLED(CONFIG_X86_32) || is_ia32_compat_frame(ksig);
+}
+
+static inline int is_x32_frame(struct ksignal *ksig)
+{
+ return IS_ENABLED(CONFIG_X86_X32_ABI) &&
+ ksig->ka.sa.sa_flags & SA_X32_ABI;
+}
+
+static int
+setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
+{
+ int usig = ksig->sig;
+ sigset_t *set = sigmask_to_save();
+ compat_sigset_t *cset = (compat_sigset_t *) set;
+
+ /*
+ * Increment event counter and perform fixup for the pre-signal
+ * frame.
+ */
+ rseq_signal_deliver(ksig, regs);
+
+ /* Set up the stack frame */
+ if (is_ia32_frame(ksig)) {
+ if (ksig->ka.sa.sa_flags & SA_SIGINFO)
+ return ia32_setup_rt_frame(usig, ksig, cset, regs);
+ else
+ return ia32_setup_frame(usig, ksig, cset, regs);
+ } else if (is_x32_frame(ksig)) {
+ return x32_setup_rt_frame(ksig, cset, regs);
+ } else {
+ return __setup_rt_frame(ksig->sig, ksig, set, regs);
+ }
+}
+
+static void
+handle_signal(struct ksignal *ksig, struct pt_regs *regs)
+{
+ bool stepping, failed;
+ struct fpu *fpu = &current->thread.fpu;
+
+ if (v8086_mode(regs))
+ save_v86_state((struct kernel_vm86_regs *) regs, VM86_SIGNAL);
+
+ /* Are we from a system call? */
+ if (syscall_get_nr(current, regs) >= 0) {
+ /* If so, check system call restarting.. */
+ switch (syscall_get_error(current, regs)) {
+ case -ERESTART_RESTARTBLOCK:
+ case -ERESTARTNOHAND:
+ regs->ax = -EINTR;
+ break;
+
+ case -ERESTARTSYS:
+ if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
+ regs->ax = -EINTR;
+ break;
+ }
+ /* fallthrough */
+ case -ERESTARTNOINTR:
+ regs->ax = regs->orig_ax;
+ regs->ip -= 2;
+ break;
+ }
+ }
+
+ /*
+ * If TF is set due to a debugger (TIF_FORCED_TF), clear TF now
+ * so that register information in the sigcontext is correct and
+ * then notify the tracer before entering the signal handler.
+ */
+ stepping = test_thread_flag(TIF_SINGLESTEP);
+ if (stepping)
+ user_disable_single_step(current);
+
+ failed = (setup_rt_frame(ksig, regs) < 0);
+ if (!failed) {
+ /*
+ * Clear the direction flag as per the ABI for function entry.
+ *
+ * Clear RF when entering the signal handler, because
+ * it might disable possible debug exception from the
+ * signal handler.
+ *
+ * Clear TF for the case when it wasn't set by debugger to
+ * avoid the recursive send_sigtrap() in SIGTRAP handler.
+ */
+ regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF);
+ /*
+ * Ensure the signal handler starts with the new fpu state.
+ */
+ if (fpu->initialized)
+ fpu__clear(fpu);
+ }
+ signal_setup_done(failed, ksig, stepping);
+}
+
+static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs)
+{
+#ifdef CONFIG_IA32_EMULATION
+ if (current_thread_info()->status & TS_COMPAT_RESTART)
+ return __NR_ia32_restart_syscall;
+#endif
+#ifdef CONFIG_X86_X32_ABI
+ return __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT);
+#else
+ return __NR_restart_syscall;
+#endif
+}
+
+/*
+ * Note that 'init' is a special process: it doesn't get signals it doesn't
+ * want to handle. Thus you cannot kill init even with a SIGKILL even by
+ * mistake.
+ */
+void do_signal(struct pt_regs *regs)
+{
+ struct ksignal ksig;
+
+ if (get_signal(&ksig)) {
+ /* Whee! Actually deliver the signal. */
+ handle_signal(&ksig, regs);
+ return;
+ }
+
+ /* Did we come from a system call? */
+ if (syscall_get_nr(current, regs) >= 0) {
+ /* Restart the system call - no handlers present */
+ switch (syscall_get_error(current, regs)) {
+ case -ERESTARTNOHAND:
+ case -ERESTARTSYS:
+ case -ERESTARTNOINTR:
+ regs->ax = regs->orig_ax;
+ regs->ip -= 2;
+ break;
+
+ case -ERESTART_RESTARTBLOCK:
+ regs->ax = get_nr_restart_syscall(regs);
+ regs->ip -= 2;
+ break;
+ }
+ }
+
+ /*
+ * If there's no signal to deliver, we just put the saved sigmask
+ * back.
+ */
+ restore_saved_sigmask();
+}
+
+void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
+{
+ struct task_struct *me = current;
+
+ if (show_unhandled_signals && printk_ratelimit()) {
+ printk("%s"
+ "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
+ task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
+ me->comm, me->pid, where, frame,
+ regs->ip, regs->sp, regs->orig_ax);
+ print_vma_addr(KERN_CONT " in ", regs->ip);
+ pr_cont("\n");
+ }
+
+ force_sig(SIGSEGV, me);
+}
+
+#ifdef CONFIG_X86_X32_ABI
+asmlinkage long sys32_x32_rt_sigreturn(void)
+{
+ struct pt_regs *regs = current_pt_regs();
+ struct rt_sigframe_x32 __user *frame;
+ sigset_t set;
+ unsigned long uc_flags;
+
+ frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
+
+ if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
+ goto badframe;
+ if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+ goto badframe;
+ if (__get_user(uc_flags, &frame->uc.uc_flags))
+ goto badframe;
+
+ set_current_blocked(&set);
+
+ if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags))
+ goto badframe;
+
+ if (compat_restore_altstack(&frame->uc.uc_stack))
+ goto badframe;
+
+ return regs->ax;
+
+badframe:
+ signal_fault(regs, frame, "x32 rt_sigreturn");
+ return 0;
+}
+#endif
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-28 20:17:18 +0000