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linux-stable/arch/x86/um/signal.c
Benjamin Berg 81e0679d85 um: fix sparse warnings in signal code 
sparse reports that various places were missing the __user tag in casts.
In addition, one location was using 0 instead of NULL.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241031142017.430420-2-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2024-11-07 17:34:50 +01:00

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/*
* Copyright (C) 2003 PathScale, Inc.
* Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#include <linux/personality.h>
#include <linux/ptrace.h>
#include <linux/kernel.h>
#include <linux/syscalls.h>
#include <asm/unistd.h>
#include <linux/uaccess.h>
#include <asm/ucontext.h>
#include <frame_kern.h>
#include <registers.h>
#include <skas.h>
#include <linux/regset.h>
#include <asm/sigframe.h>
#ifdef CONFIG_X86_32
struct _xstate_64 {
struct _fpstate_64 fpstate;
struct _header xstate_hdr;
struct _ymmh_state ymmh;
/* New processor state extensions go here: */
};
#else
#define _xstate_64 _xstate
#endif
static int copy_sc_from_user(struct pt_regs *regs,
struct sigcontext __user *from)
{
struct _xstate_64 __user *from_fp64;
struct sigcontext sc;
int err;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
err = copy_from_user(&sc, from, sizeof(sc));
if (err)
return err;
#define GETREG(regno, regname) regs->regs.gp[HOST_##regno] = sc.regname
#ifdef CONFIG_X86_32
GETREG(GS, gs);
GETREG(FS, fs);
GETREG(ES, es);
GETREG(DS, ds);
#endif
GETREG(DI, di);
GETREG(SI, si);
GETREG(BP, bp);
GETREG(SP, sp);
GETREG(BX, bx);
GETREG(DX, dx);
GETREG(CX, cx);
GETREG(AX, ax);
GETREG(IP, ip);
#ifdef CONFIG_X86_64
GETREG(R8, r8);
GETREG(R9, r9);
GETREG(R10, r10);
GETREG(R11, r11);
GETREG(R12, r12);
GETREG(R13, r13);
GETREG(R14, r14);
GETREG(R15, r15);
#endif
GETREG(CS, cs);
GETREG(EFLAGS, flags);
#ifdef CONFIG_X86_32
GETREG(SS, ss);
#endif
#undef GETREG
#ifdef CONFIG_X86_32
from_fp64 = ((void __user *)sc.fpstate) +
offsetof(struct _fpstate_32, _fxsr_env);
#else
from_fp64 = (void __user *)sc.fpstate;
#endif
err = copy_from_user(regs->regs.fp, from_fp64, host_fp_size);
if (err)
return 1;
#ifdef CONFIG_X86_32
/* Data is duplicated and this copy is the important one */
err = copy_regset_from_user(current,
task_user_regset_view(current),
REGSET_FP_LEGACY, 0,
sizeof(struct user_i387_struct),
(void __user *)sc.fpstate);
if (err < 0)
return err;
#endif
return 0;
}
static int copy_sc_to_user(struct sigcontext __user *to,
struct _xstate __user *to_fp, struct pt_regs *regs,
unsigned long mask)
{
struct _xstate_64 __user *to_fp64;
struct sigcontext sc;
struct faultinfo * fi = &current->thread.arch.faultinfo;
int err;
memset(&sc, 0, sizeof(struct sigcontext));
#define PUTREG(regno, regname) sc.regname = regs->regs.gp[HOST_##regno]
#ifdef CONFIG_X86_32
PUTREG(GS, gs);
PUTREG(FS, fs);
PUTREG(ES, es);
PUTREG(DS, ds);
#endif
PUTREG(DI, di);
PUTREG(SI, si);
PUTREG(BP, bp);
PUTREG(SP, sp);
PUTREG(BX, bx);
PUTREG(DX, dx);
PUTREG(CX, cx);
PUTREG(AX, ax);
#ifdef CONFIG_X86_64
PUTREG(R8, r8);
PUTREG(R9, r9);
PUTREG(R10, r10);
PUTREG(R11, r11);
PUTREG(R12, r12);
PUTREG(R13, r13);
PUTREG(R14, r14);
PUTREG(R15, r15);
#endif
sc.cr2 = fi->cr2;
sc.err = fi->error_code;
sc.trapno = fi->trap_no;
PUTREG(IP, ip);
PUTREG(CS, cs);
PUTREG(EFLAGS, flags);
#ifdef CONFIG_X86_32
PUTREG(SP, sp_at_signal);
PUTREG(SS, ss);
#endif
#undef PUTREG
sc.oldmask = mask;
sc.fpstate = (unsigned long)to_fp;
err = copy_to_user(to, &sc, sizeof(struct sigcontext));
if (err)
return 1;
#ifdef CONFIG_X86_32
err = copy_regset_to_user(current,
task_user_regset_view(current),
REGSET_FP_LEGACY, 0,
sizeof(struct _fpstate_32), to_fp);
if (err < 0)
return err;
__put_user(X86_FXSR_MAGIC, &to_fp->fpstate.magic);
BUILD_BUG_ON(offsetof(struct _xstate, xstate_hdr) !=
offsetof(struct _xstate_64, xstate_hdr) +
offsetof(struct _fpstate_32, _fxsr_env));
to_fp64 = (void __user *)to_fp +
offsetof(struct _fpstate_32, _fxsr_env);
#else
to_fp64 = to_fp;
#endif /* CONFIG_X86_32 */
if (copy_to_user(to_fp64, regs->regs.fp, host_fp_size))
return 1;
/*
* Put magic/size values for userspace. We do not bother to verify them
* later on, however, userspace needs them should it try to read the
* XSTATE data. And ptrace does not fill in these parts.
*/
BUILD_BUG_ON(sizeof(int) != FP_XSTATE_MAGIC2_SIZE);
#ifdef CONFIG_X86_32
__put_user(offsetof(struct _fpstate_32, _fxsr_env) +
host_fp_size + FP_XSTATE_MAGIC2_SIZE,
&to_fp64->fpstate.sw_reserved.extended_size);
#else
__put_user(host_fp_size + FP_XSTATE_MAGIC2_SIZE,
&to_fp64->fpstate.sw_reserved.extended_size);
#endif
__put_user(host_fp_size, &to_fp64->fpstate.sw_reserved.xstate_size);
__put_user(FP_XSTATE_MAGIC1, &to_fp64->fpstate.sw_reserved.magic1);
__put_user(FP_XSTATE_MAGIC2,
(int __user *)((void __user *)to_fp64 + host_fp_size));
return 0;
}
#ifdef CONFIG_X86_32
static int copy_ucontext_to_user(struct ucontext __user *uc,
struct _xstate __user *fp, sigset_t *set,
unsigned long sp)
{
int err = 0;
err |= __save_altstack(&uc->uc_stack, sp);
err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs, 0);
err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
return err;
}
int setup_signal_stack_sc(unsigned long stack_top, struct ksignal *ksig,
struct pt_regs *regs, sigset_t *mask)
{
size_t math_size = offsetof(struct _fpstate_32, _fxsr_env) +
host_fp_size + FP_XSTATE_MAGIC2_SIZE;
struct sigframe __user *frame;
void __user *restorer;
int err = 0, sig = ksig->sig;
unsigned long fp_to;
/* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */
stack_top = ((stack_top + 4) & -16UL) - 4;
frame = (struct sigframe __user *) stack_top - 1;
if (!access_ok(frame, sizeof(*frame)))
return 1;
/* Add required space for math frame */
frame = (struct sigframe __user *)((unsigned long)frame - math_size);
restorer = frame->retcode;
if (ksig->ka.sa.sa_flags & SA_RESTORER)
restorer = ksig->ka.sa.sa_restorer;
err |= __put_user(restorer, (void __user * __user *)&frame->pretcode);
err |= __put_user(sig, &frame->sig);
fp_to = (unsigned long)frame + sizeof(*frame);
err |= copy_sc_to_user(&frame->sc,
(struct _xstate __user *)fp_to,
regs, mask->sig[0]);
if (_NSIG_WORDS > 1)
err |= __copy_to_user(&frame->extramask, &mask->sig[1],
sizeof(frame->extramask));
/*
* This is popl %eax ; movl $,%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(0xb858, (short __user *)(frame->retcode+0));
err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
if (err)
return err;
PT_REGS_SP(regs) = (unsigned long) frame;
PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
PT_REGS_AX(regs) = (unsigned long) sig;
PT_REGS_DX(regs) = (unsigned long) 0;
PT_REGS_CX(regs) = (unsigned long) 0;
return 0;
}
int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig,
struct pt_regs *regs, sigset_t *mask)
{
size_t math_size = offsetof(struct _fpstate_32, _fxsr_env) +
host_fp_size + FP_XSTATE_MAGIC2_SIZE;
struct rt_sigframe __user *frame;
void __user *restorer;
int err = 0, sig = ksig->sig;
unsigned long fp_to;
stack_top &= -8UL;
frame = (struct rt_sigframe __user *) stack_top - 1;
if (!access_ok(frame, sizeof(*frame)))
return 1;
/* Add required space for math frame */
frame = (struct rt_sigframe __user *)((unsigned long)frame - math_size);
restorer = frame->retcode;
if (ksig->ka.sa.sa_flags & SA_RESTORER)
restorer = ksig->ka.sa.sa_restorer;
err |= __put_user(restorer, (void __user * __user *)&frame->pretcode);
err |= __put_user(sig, &frame->sig);
err |= __put_user(&frame->info, (void __user * __user *)&frame->pinfo);
err |= __put_user(&frame->uc, (void __user * __user *)&frame->puc);
err |= copy_siginfo_to_user(&frame->info, &ksig->info);
fp_to = (unsigned long)frame + sizeof(*frame);
err |= copy_ucontext_to_user(&frame->uc, (struct _xstate __user *)fp_to,
mask, PT_REGS_SP(regs));
/*
* This is movl $,%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(0xb8, (char __user *)(frame->retcode+0));
err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
if (err)
return err;
PT_REGS_SP(regs) = (unsigned long) frame;
PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
PT_REGS_AX(regs) = (unsigned long) sig;
PT_REGS_DX(regs) = (unsigned long) &frame->info;
PT_REGS_CX(regs) = (unsigned long) &frame->uc;
return 0;
}
SYSCALL_DEFINE0(sigreturn)
{
unsigned long sp = PT_REGS_SP(&current->thread.regs);
struct sigframe __user *frame = (struct sigframe __user *)(sp - 8);
sigset_t set;
struct sigcontext __user *sc = &frame->sc;
int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);
if (copy_from_user(&set.sig[0], &sc->oldmask, sizeof(set.sig[0])) ||
copy_from_user(&set.sig[1], frame->extramask, sig_size))
goto segfault;
set_current_blocked(&set);
if (copy_sc_from_user(&current->thread.regs, sc))
goto segfault;
/* Avoid ERESTART handling */
PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
return PT_REGS_SYSCALL_RET(&current->thread.regs);
segfault:
force_sig(SIGSEGV);
return 0;
}
#else
int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig,
struct pt_regs *regs, sigset_t *set)
{
unsigned long math_size = host_fp_size + FP_XSTATE_MAGIC2_SIZE;
struct rt_sigframe __user *frame;
int err = 0, sig = ksig->sig;
unsigned long fp_to;
frame = (struct rt_sigframe __user *)
round_down(stack_top - sizeof(struct rt_sigframe), 16);
/* Add required space for math frame */
frame = (struct rt_sigframe __user *)((unsigned long)frame - math_size);
/* Subtract 128 for a red zone and 8 for proper alignment */
frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8);
if (!access_ok(frame, sizeof(*frame) + math_size))
goto out;
if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
err |= copy_siginfo_to_user(&frame->info, &ksig->info);
if (err)
goto out;
}
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(NULL, &frame->uc.uc_link);
err |= __save_altstack(&frame->uc.uc_stack, PT_REGS_SP(regs));
fp_to = (unsigned long)frame + sizeof(*frame);
err |= copy_sc_to_user(&frame->uc.uc_mcontext,
(struct _xstate __user *)fp_to,
regs, set->sig[0]);
err |= __put_user(fp_to, &frame->uc.uc_mcontext.fpstate);
if (sizeof(*set) == 16) {
err |= __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
err |= __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
}
else
err |= __copy_to_user(&frame->uc.uc_sigmask, set,
sizeof(*set));
/*
* 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)
err |= __put_user((void __user *)ksig->ka.sa.sa_restorer,
&frame->pretcode);
else
/* could use a vstub here */
return err;
if (err)
return err;
PT_REGS_SP(regs) = (unsigned long) frame;
PT_REGS_DI(regs) = sig;
/* In case the signal handler was declared without prototypes */
PT_REGS_AX(regs) = 0;
/*
* This also works for non SA_SIGINFO handlers because they expect the
* next argument after the signal number on the stack.
*/
PT_REGS_SI(regs) = (unsigned long) &frame->info;
PT_REGS_DX(regs) = (unsigned long) &frame->uc;
PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
out:
return err;
}
#endif
SYSCALL_DEFINE0(rt_sigreturn)
{
unsigned long sp = PT_REGS_SP(&current->thread.regs);
struct rt_sigframe __user *frame =
(struct rt_sigframe __user *)(sp - sizeof(long));
struct ucontext __user *uc = &frame->uc;
sigset_t set;
if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
goto segfault;
set_current_blocked(&set);
if (copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext))
goto segfault;
/* Avoid ERESTART handling */
PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
return PT_REGS_SYSCALL_RET(&current->thread.regs);
segfault:
force_sig(SIGSEGV);
return 0;
}
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