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sparc32: fix register window handling in genregs32_[gs]et()
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It needs access_process_vm() if the traced process does not share
mm with the caller.  Solution is similar to what sparc64 does.
Note that genregs32_set() is only ever called with pos being 0
or 32 * sizeof(u32) (the latter - as part of PTRACE_SETREGS
handling).

Cc: stable@kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro committed May 20, 2020
1 parent 142cd25 commit cf51e12
Showing 1 changed file with 98 additions and 130 deletions.
228 changes: 98 additions & 130 deletions arch/sparc/kernel/ptrace_32.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -46,82 +46,79 @@ enum sparc_regset {
REGSET_FP,
};

static int regwindow32_get(struct task_struct *target,
const struct pt_regs *regs,
u32 *uregs)
{
unsigned long reg_window = regs->u_regs[UREG_I6];
int size = 16 * sizeof(u32);

if (target == current) {
if (copy_from_user(uregs, (void __user *)reg_window, size))
return -EFAULT;
} else {
if (access_process_vm(target, reg_window, uregs, size,
FOLL_FORCE) != size)
return -EFAULT;
}
return 0;
}

static int regwindow32_set(struct task_struct *target,
const struct pt_regs *regs,
u32 *uregs)
{
unsigned long reg_window = regs->u_regs[UREG_I6];
int size = 16 * sizeof(u32);

if (target == current) {
if (copy_to_user((void __user *)reg_window, uregs, size))
return -EFAULT;
} else {
if (access_process_vm(target, reg_window, uregs, size,
FOLL_FORCE | FOLL_WRITE) != size)
return -EFAULT;
}
return 0;
}

static int genregs32_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 = target->thread.kregs;
unsigned long __user *reg_window;
unsigned long *k = kbuf;
unsigned long __user *u = ubuf;
unsigned long reg;
u32 uregs[16];
int ret;

if (target == current)
flush_user_windows();

pos /= sizeof(reg);
count /= sizeof(reg);

if (kbuf) {
for (; count > 0 && pos < 16; count--)
*k++ = regs->u_regs[pos++];

reg_window = (unsigned long __user *) regs->u_regs[UREG_I6];
reg_window -= 16;
for (; count > 0 && pos < 32; count--) {
if (get_user(*k++, &reg_window[pos++]))
return -EFAULT;
}
} else {
for (; count > 0 && pos < 16; count--) {
if (put_user(regs->u_regs[pos++], u++))
return -EFAULT;
}

reg_window = (unsigned long __user *) regs->u_regs[UREG_I6];
reg_window -= 16;
for (; count > 0 && pos < 32; count--) {
if (get_user(reg, &reg_window[pos++]) ||
put_user(reg, u++))
return -EFAULT;
}
}
while (count > 0) {
switch (pos) {
case 32: /* PSR */
reg = regs->psr;
break;
case 33: /* PC */
reg = regs->pc;
break;
case 34: /* NPC */
reg = regs->npc;
break;
case 35: /* Y */
reg = regs->y;
break;
case 36: /* WIM */
case 37: /* TBR */
reg = 0;
break;
default:
goto finish;
}
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
regs->u_regs,
0, 16 * sizeof(u32));
if (ret || !count)
return ret;

if (kbuf)
*k++ = reg;
else if (put_user(reg, u++))
if (pos < 32 * sizeof(u32)) {
if (regwindow32_get(target, regs, uregs))
return -EFAULT;
pos++;
count--;
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
uregs,
16 * sizeof(u32), 32 * sizeof(u32));
if (ret || !count)
return ret;
}
finish:
pos *= sizeof(reg);
count *= sizeof(reg);

return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
38 * sizeof(reg), -1);
uregs[0] = regs->psr;
uregs[1] = regs->pc;
uregs[2] = regs->npc;
uregs[3] = regs->y;
uregs[4] = 0; /* WIM */
uregs[5] = 0; /* TBR */
return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
uregs,
32 * sizeof(u32), 38 * sizeof(u32));
}

static int genregs32_set(struct task_struct *target,
Expand All @@ -130,82 +127,53 @@ static int genregs32_set(struct task_struct *target,
const void *kbuf, const void __user *ubuf)
{
struct pt_regs *regs = target->thread.kregs;
unsigned long __user *reg_window;
const unsigned long *k = kbuf;
const unsigned long __user *u = ubuf;
unsigned long reg;
u32 uregs[16];
u32 psr;
int ret;

if (target == current)
flush_user_windows();

pos /= sizeof(reg);
count /= sizeof(reg);

if (kbuf) {
for (; count > 0 && pos < 16; count--)
regs->u_regs[pos++] = *k++;

reg_window = (unsigned long __user *) regs->u_regs[UREG_I6];
reg_window -= 16;
for (; count > 0 && pos < 32; count--) {
if (put_user(*k++, &reg_window[pos++]))
return -EFAULT;
}
} else {
for (; count > 0 && pos < 16; count--) {
if (get_user(reg, u++))
return -EFAULT;
regs->u_regs[pos++] = reg;
}

reg_window = (unsigned long __user *) regs->u_regs[UREG_I6];
reg_window -= 16;
for (; count > 0 && pos < 32; count--) {
if (get_user(reg, u++) ||
put_user(reg, &reg_window[pos++]))
return -EFAULT;
}
}
while (count > 0) {
unsigned long psr;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
regs->u_regs,
0, 16 * sizeof(u32));
if (ret || !count)
return ret;

if (kbuf)
reg = *k++;
else if (get_user(reg, u++))
if (pos < 32 * sizeof(u32)) {
if (regwindow32_get(target, regs, uregs))
return -EFAULT;

switch (pos) {
case 32: /* PSR */
psr = regs->psr;
psr &= ~(PSR_ICC | PSR_SYSCALL);
psr |= (reg & (PSR_ICC | PSR_SYSCALL));
regs->psr = psr;
break;
case 33: /* PC */
regs->pc = reg;
break;
case 34: /* NPC */
regs->npc = reg;
break;
case 35: /* Y */
regs->y = reg;
break;
case 36: /* WIM */
case 37: /* TBR */
break;
default:
goto finish;
}

pos++;
count--;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
uregs,
16 * sizeof(u32), 32 * sizeof(u32));
if (ret)
return ret;
if (regwindow32_set(target, regs, uregs))
return -EFAULT;
if (!count)
return 0;
}
finish:
pos *= sizeof(reg);
count *= sizeof(reg);

ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&psr,
32 * sizeof(u32), 33 * sizeof(u32));
if (ret)
return ret;
regs->psr = (regs->psr & ~(PSR_ICC | PSR_SYSCALL)) |
(psr & (PSR_ICC | PSR_SYSCALL));
if (!count)
return 0;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&regs->pc,
33 * sizeof(u32), 34 * sizeof(u32));
if (ret || !count)
return ret;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&regs->y,
34 * sizeof(u32), 35 * sizeof(u32));
if (ret || !count)
return ret;
return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
38 * sizeof(reg), -1);
35 * sizeof(u32), 38 * sizeof(u32));
}

static int fpregs32_get(struct task_struct *target,
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