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d7e7528bcd
linux_dsm_epyc7002/arch/sh/kernel/ptrace_64.c
Eric Paris d7e7528bcd Audit: push audit success and retcode into arch ptrace.h 
The audit system previously expected arches calling to audit_syscall_exit to
supply as arguments if the syscall was a success and what the return code was.
Audit also provides a helper AUDITSC_RESULT which was supposed to simplify things
by converting from negative retcodes to an audit internal magic value stating
success or failure.  This helper was wrong and could indicate that a valid
pointer returned to userspace was a failed syscall.  The fix is to fix the
layering foolishness.  We now pass audit_syscall_exit a struct pt_reg and it
in turns calls back into arch code to collect the return value and to
determine if the syscall was a success or failure.  We also define a generic
is_syscall_success() macro which determines success/failure based on if the
value is < -MAX_ERRNO.  This works for arches like x86 which do not use a
separate mechanism to indicate syscall failure.

We make both the is_syscall_success() and regs_return_value() static inlines
instead of macros.  The reason is because the audit function must take a void*
for the regs.  (uml calls theirs struct uml_pt_regs instead of just struct
pt_regs so audit_syscall_exit can't take a struct pt_regs).  Since the audit
function takes a void* we need to use static inlines to cast it back to the
arch correct structure to dereference it.

The other major change is that on some arches, like ia64, MIPS and ppc, we
change regs_return_value() to give us the negative value on syscall failure.
THE only other user of this macro, kretprobe_example.c, won't notice and it
makes the value signed consistently for the audit functions across all archs.

In arch/sh/kernel/ptrace_64.c I see that we were using regs[9] in the old
audit code as the return value.  But the ptrace_64.h code defined the macro
regs_return_value() as regs[3].  I have no idea which one is correct, but this
patch now uses the regs_return_value() function, so it now uses regs[3].

For powerpc we previously used regs->result but now use the
regs_return_value() function which uses regs->gprs[3].  regs->gprs[3] is
always positive so the regs_return_value(), much like ia64 makes it negative
before calling the audit code when appropriate.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: H. Peter Anvin <hpa@zytor.com> [for x86 portion]
Acked-by: Tony Luck <tony.luck@intel.com> [for ia64]
Acked-by: Richard Weinberger <richard@nod.at> [for uml]
Acked-by: David S. Miller <davem@davemloft.net> [for sparc]
Acked-by: Ralf Baechle <ralf@linux-mips.org> [for mips]
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> [for ppc]
2012-01-17 16:16:56 -05:00

595 lines
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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/system.h>
#include <asm/processor.h>
#include <asm/mmu_context.h>
#include <asm/syscalls.h>
#include <asm/fpu.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(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]);
if (unlikely(current->audit_context))
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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