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linux-next/arch/sh/kernel/ptrace_64.c
Will Drewry e4da89d02f seccomp: ignore secure_computing return values 
This change is inspired by
  https://lkml.org/lkml/2012/4/16/14
which fixes the build warnings for arches that don't support
CONFIG_HAVE_ARCH_SECCOMP_FILTER.

In particular, there is no requirement for the return value of
secure_computing() to be checked unless the architecture supports
seccomp filter.  Instead of silencing the warnings with (void)
a new static inline is added to encode the expected behavior
in a compiler and human friendly way.

v2: - cleans things up with a static inline
    - removes sfr's signed-off-by since it is a different approach
v1: - matches sfr's original change

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Will Drewry <wad@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-04-18 12:24:50 +10:00

594 lines
14 KiB
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/*
* arch/sh/kernel/ptrace_64.c
*
* Copyright (C) 2000, 2001 Paolo Alberelli
* Copyright (C) 2003 - 2008 Paul Mundt
*
* Started from SH3/4 version:
* SuperH version: Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka
*
* Original x86 implementation:
* By Ross Biro 1/23/92
* edited by Linus Torvalds
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/kernel.h>
#include <linux/rwsem.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/signal.h>
#include <linux/syscalls.h>
#include <linux/audit.h>
#include <linux/seccomp.h>
#include <linux/tracehook.h>
#include <linux/elf.h>
#include <linux/regset.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/mmu_context.h>
#include <asm/syscalls.h>
#include <asm/fpu.h>
#include <asm/traps.h>
#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>
/* This mask defines the bits of the SR which the user is not allowed to
change, which are everything except S, Q, M, PR, SZ, FR. */
#define SR_MASK (0xffff8cfd)
/*
* does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.
*/
/*
* This routine will get a word from the user area in the process kernel stack.
*/
static inline int get_stack_long(struct task_struct *task, int offset)
{
unsigned char *stack;
stack = (unsigned char *)(task->thread.uregs);
stack += offset;
return (*((int *)stack));
}
static inline unsigned long
get_fpu_long(struct task_struct *task, unsigned long addr)
{
unsigned long tmp;
struct pt_regs *regs;
regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
if (!tsk_used_math(task)) {
if (addr == offsetof(struct user_fpu_struct, fpscr)) {
tmp = FPSCR_INIT;
} else {
tmp = 0xffffffffUL; /* matches initial value in fpu.c */
}
return tmp;
}
if (last_task_used_math == task) {
enable_fpu();
save_fpu(task);
disable_fpu();
last_task_used_math = 0;
regs->sr |= SR_FD;
}
tmp = ((long *)task->thread.xstate)[addr / sizeof(unsigned long)];
return tmp;
}
/*
* This routine will put a word into the user area in the process kernel stack.
*/
static inline int put_stack_long(struct task_struct *task, int offset,
unsigned long data)
{
unsigned char *stack;
stack = (unsigned char *)(task->thread.uregs);
stack += offset;
*(unsigned long *) stack = data;
return 0;
}
static inline int
put_fpu_long(struct task_struct *task, unsigned long addr, unsigned long data)
{
struct pt_regs *regs;
regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
if (!tsk_used_math(task)) {
init_fpu(task);
} else if (last_task_used_math == task) {
enable_fpu();
save_fpu(task);
disable_fpu();
last_task_used_math = 0;
regs->sr |= SR_FD;
}
((long *)task->thread.xstate)[addr / sizeof(unsigned long)] = data;
return 0;
}
void user_enable_single_step(struct task_struct *child)
{
struct pt_regs *regs = child->thread.uregs;
regs->sr |= SR_SSTEP; /* auto-resetting upon exception */
set_tsk_thread_flag(child, TIF_SINGLESTEP);
}
void user_disable_single_step(struct task_struct *child)
{
struct pt_regs *regs = child->thread.uregs;
regs->sr &= ~SR_SSTEP;
clear_tsk_thread_flag(child, TIF_SINGLESTEP);
}
static int genregs_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
const struct pt_regs *regs = task_pt_regs(target);
int ret;
/* PC, SR, SYSCALL */
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&regs->pc,
0, 3 * sizeof(unsigned long long));
/* R1 -> R63 */
if (!ret)
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
regs->regs,
offsetof(struct pt_regs, regs[0]),
63 * sizeof(unsigned long long));
/* TR0 -> TR7 */
if (!ret)
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
regs->tregs,
offsetof(struct pt_regs, tregs[0]),
8 * sizeof(unsigned long long));
if (!ret)
ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
sizeof(struct pt_regs), -1);
return ret;
}
static int genregs_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
struct pt_regs *regs = task_pt_regs(target);
int ret;
/* PC, SR, SYSCALL */
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&regs->pc,
0, 3 * sizeof(unsigned long long));
/* R1 -> R63 */
if (!ret && count > 0)
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
regs->regs,
offsetof(struct pt_regs, regs[0]),
63 * sizeof(unsigned long long));
/* TR0 -> TR7 */
if (!ret && count > 0)
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
regs->tregs,
offsetof(struct pt_regs, tregs[0]),
8 * sizeof(unsigned long long));
if (!ret)
ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
sizeof(struct pt_regs), -1);
return ret;
}
#ifdef CONFIG_SH_FPU
int fpregs_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
int ret;
ret = init_fpu(target);
if (ret)
return ret;
return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&target->thread.xstate->hardfpu, 0, -1);
}
static int fpregs_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
int ret;
ret = init_fpu(target);
if (ret)
return ret;
set_stopped_child_used_math(target);
return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&target->thread.xstate->hardfpu, 0, -1);
}
static int fpregs_active(struct task_struct *target,
const struct user_regset *regset)
{
return tsk_used_math(target) ? regset->n : 0;
}
#endif
const struct pt_regs_offset regoffset_table[] = {
REG_OFFSET_NAME(pc),
REG_OFFSET_NAME(sr),
REG_OFFSET_NAME(syscall_nr),
REGS_OFFSET_NAME(0),
REGS_OFFSET_NAME(1),
REGS_OFFSET_NAME(2),
REGS_OFFSET_NAME(3),
REGS_OFFSET_NAME(4),
REGS_OFFSET_NAME(5),
REGS_OFFSET_NAME(6),
REGS_OFFSET_NAME(7),
REGS_OFFSET_NAME(8),
REGS_OFFSET_NAME(9),
REGS_OFFSET_NAME(10),
REGS_OFFSET_NAME(11),
REGS_OFFSET_NAME(12),
REGS_OFFSET_NAME(13),
REGS_OFFSET_NAME(14),
REGS_OFFSET_NAME(15),
REGS_OFFSET_NAME(16),
REGS_OFFSET_NAME(17),
REGS_OFFSET_NAME(18),
REGS_OFFSET_NAME(19),
REGS_OFFSET_NAME(20),
REGS_OFFSET_NAME(21),
REGS_OFFSET_NAME(22),
REGS_OFFSET_NAME(23),
REGS_OFFSET_NAME(24),
REGS_OFFSET_NAME(25),
REGS_OFFSET_NAME(26),
REGS_OFFSET_NAME(27),
REGS_OFFSET_NAME(28),
REGS_OFFSET_NAME(29),
REGS_OFFSET_NAME(30),
REGS_OFFSET_NAME(31),
REGS_OFFSET_NAME(32),
REGS_OFFSET_NAME(33),
REGS_OFFSET_NAME(34),
REGS_OFFSET_NAME(35),
REGS_OFFSET_NAME(36),
REGS_OFFSET_NAME(37),
REGS_OFFSET_NAME(38),
REGS_OFFSET_NAME(39),
REGS_OFFSET_NAME(40),
REGS_OFFSET_NAME(41),
REGS_OFFSET_NAME(42),
REGS_OFFSET_NAME(43),
REGS_OFFSET_NAME(44),
REGS_OFFSET_NAME(45),
REGS_OFFSET_NAME(46),
REGS_OFFSET_NAME(47),
REGS_OFFSET_NAME(48),
REGS_OFFSET_NAME(49),
REGS_OFFSET_NAME(50),
REGS_OFFSET_NAME(51),
REGS_OFFSET_NAME(52),
REGS_OFFSET_NAME(53),
REGS_OFFSET_NAME(54),
REGS_OFFSET_NAME(55),
REGS_OFFSET_NAME(56),
REGS_OFFSET_NAME(57),
REGS_OFFSET_NAME(58),
REGS_OFFSET_NAME(59),
REGS_OFFSET_NAME(60),
REGS_OFFSET_NAME(61),
REGS_OFFSET_NAME(62),
REGS_OFFSET_NAME(63),
TREGS_OFFSET_NAME(0),
TREGS_OFFSET_NAME(1),
TREGS_OFFSET_NAME(2),
TREGS_OFFSET_NAME(3),
TREGS_OFFSET_NAME(4),
TREGS_OFFSET_NAME(5),
TREGS_OFFSET_NAME(6),
TREGS_OFFSET_NAME(7),
REG_OFFSET_END,
};
/*
* These are our native regset flavours.
*/
enum sh_regset {
REGSET_GENERAL,
#ifdef CONFIG_SH_FPU
REGSET_FPU,
#endif
};
static const struct user_regset sh_regsets[] = {
/*
* Format is:
* PC, SR, SYSCALL,
* R1 --> R63,
* TR0 --> TR7,
*/
[REGSET_GENERAL] = {
.core_note_type = NT_PRSTATUS,
.n = ELF_NGREG,
.size = sizeof(long long),
.align = sizeof(long long),
.get = genregs_get,
.set = genregs_set,
},
#ifdef CONFIG_SH_FPU
[REGSET_FPU] = {
.core_note_type = NT_PRFPREG,
.n = sizeof(struct user_fpu_struct) /
sizeof(long long),
.size = sizeof(long long),
.align = sizeof(long long),
.get = fpregs_get,
.set = fpregs_set,
.active = fpregs_active,
},
#endif
};
static const struct user_regset_view user_sh64_native_view = {
.name = "sh64",
.e_machine = EM_SH,
.regsets = sh_regsets,
.n = ARRAY_SIZE(sh_regsets),
};
const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
return &user_sh64_native_view;
}
long arch_ptrace(struct task_struct *child, long request,
unsigned long addr, unsigned long data)
{
int ret;
unsigned long __user *datap = (unsigned long __user *) data;
switch (request) {
/* read the word at location addr in the USER area. */
case PTRACE_PEEKUSR: {
unsigned long tmp;
ret = -EIO;
if ((addr & 3) || addr < 0)
break;
if (addr < sizeof(struct pt_regs))
tmp = get_stack_long(child, addr);
else if ((addr >= offsetof(struct user, fpu)) &&
(addr < offsetof(struct user, u_fpvalid))) {
unsigned long index;
ret = init_fpu(child);
if (ret)
break;
index = addr - offsetof(struct user, fpu);
tmp = get_fpu_long(child, index);
} else if (addr == offsetof(struct user, u_fpvalid)) {
tmp = !!tsk_used_math(child);
} else {
break;
}
ret = put_user(tmp, datap);
break;
}
case PTRACE_POKEUSR:
/* write the word at location addr in the USER area. We must
disallow any changes to certain SR bits or u_fpvalid, since
this could crash the kernel or result in a security
loophole. */
ret = -EIO;
if ((addr & 3) || addr < 0)
break;
if (addr < sizeof(struct pt_regs)) {
/* Ignore change of top 32 bits of SR */
if (addr == offsetof (struct pt_regs, sr)+4)
{
ret = 0;
break;
}
/* If lower 32 bits of SR, ignore non-user bits */
if (addr == offsetof (struct pt_regs, sr))
{
long cursr = get_stack_long(child, addr);
data &= ~(SR_MASK);
data |= (cursr & SR_MASK);
}
ret = put_stack_long(child, addr, data);
}
else if ((addr >= offsetof(struct user, fpu)) &&
(addr < offsetof(struct user, u_fpvalid))) {
unsigned long index;
ret = init_fpu(child);
if (ret)
break;
index = addr - offsetof(struct user, fpu);
ret = put_fpu_long(child, index, data);
}
break;
case PTRACE_GETREGS:
return copy_regset_to_user(child, &user_sh64_native_view,
REGSET_GENERAL,
0, sizeof(struct pt_regs),
datap);
case PTRACE_SETREGS:
return copy_regset_from_user(child, &user_sh64_native_view,
REGSET_GENERAL,
0, sizeof(struct pt_regs),
datap);
#ifdef CONFIG_SH_FPU
case PTRACE_GETFPREGS:
return copy_regset_to_user(child, &user_sh64_native_view,
REGSET_FPU,
0, sizeof(struct user_fpu_struct),
datap);
case PTRACE_SETFPREGS:
return copy_regset_from_user(child, &user_sh64_native_view,
REGSET_FPU,
0, sizeof(struct user_fpu_struct),
datap);
#endif
default:
ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}
asmlinkage int sh64_ptrace(long request, long pid,
unsigned long addr, unsigned long data)
{
#define WPC_DBRMODE 0x0d104008
static unsigned long first_call;
if (!test_and_set_bit(0, &first_call)) {
/* Set WPC.DBRMODE to 0. This makes all debug events get
* delivered through RESVEC, i.e. into the handlers in entry.S.
* (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
* would normally be left set to 1, which makes debug events get
* delivered through DBRVEC, i.e. into the remote gdb's
* handlers. This prevents ptrace getting them, and confuses
* the remote gdb.) */
printk("DBRMODE set to 0 to permit native debugging\n");
poke_real_address_q(WPC_DBRMODE, 0);
}
return sys_ptrace(request, pid, addr, data);
}
static inline int audit_arch(void)
{
int arch = EM_SH;
#ifdef CONFIG_64BIT
arch |= __AUDIT_ARCH_64BIT;
#endif
#ifdef CONFIG_CPU_LITTLE_ENDIAN
arch |= __AUDIT_ARCH_LE;
#endif
return arch;
}
asmlinkage long long do_syscall_trace_enter(struct pt_regs *regs)
{
long long ret = 0;
secure_computing_strict(regs->regs[9]);
if (test_thread_flag(TIF_SYSCALL_TRACE) &&
tracehook_report_syscall_entry(regs))
/*
* Tracing decided this syscall should not happen.
* We'll return a bogus call number to get an ENOSYS
* error, but leave the original number in regs->regs[0].
*/
ret = -1LL;
if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
trace_sys_enter(regs, regs->regs[9]);
audit_syscall_entry(audit_arch(), regs->regs[1],
regs->regs[2], regs->regs[3],
regs->regs[4], regs->regs[5]);
return ret ?: regs->regs[9];
}
asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
{
int step;
audit_syscall_exit(regs);
if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
trace_sys_exit(regs, regs->regs[9]);
step = test_thread_flag(TIF_SINGLESTEP);
if (step || test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall_exit(regs, step);
}
/* Called with interrupts disabled */
asmlinkage void do_single_step(unsigned long long vec, struct pt_regs *regs)
{
/* This is called after a single step exception (DEBUGSS).
There is no need to change the PC, as it is a post-execution
exception, as entry.S does not do anything to the PC for DEBUGSS.
We need to clear the Single Step setting in SR to avoid
continually stepping. */
local_irq_enable();
regs->sr &= ~SR_SSTEP;
force_sig(SIGTRAP, current);
}
/* Called with interrupts disabled */
BUILD_TRAP_HANDLER(breakpoint)
{
TRAP_HANDLER_DECL;
/* We need to forward step the PC, to counteract the backstep done
in signal.c. */
local_irq_enable();
force_sig(SIGTRAP, current);
regs->pc += 4;
}
/*
* Called by kernel/ptrace.c when detaching..
*
* Make sure single step bits etc are not set.
*/
void ptrace_disable(struct task_struct *child)
{
user_disable_single_step(child);
}
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