[PATCH 4.14 174/190] sparc32: fix register window handling in genregs32_[gs]et()

Greg Kroah-Hartman
2020-06-19T16:32:15Z

From: Al Viro <viro@zeniv.linux.org.uk>

commit cf51e129b96847f969bfb8af1ee1516a01a70b39 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/sparc/kernel/ptrace_32.c | 230 ++++++++++++++++++------------------------
1 file changed, 99 insertions(+), 131 deletions(-)

--- a/arch/sparc/kernel/ptrace_32.c
+++ b/arch/sparc/kernel/ptrace_32.c
@@ -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);
+ ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+ regs->u_regs,
+ 0, 16 * sizeof(u32));
+ if (ret || !count)
+ return ret;

- 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;
- }
-
- 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,
@@ -130,82 +127,53 @@ static int genregs32_set(struct task_str
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;
-
- if (kbuf)
- reg = *k++;
- else if (get_user(reg, u++))
- 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;
- }
+ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+ regs->u_regs,
+ 0, 16 * sizeof(u32));
+ if (ret || !count)
+ return ret;

- pos++;
- count--;
+ if (pos < 32 * sizeof(u32)) {
+ if (regwindow32_get(target, regs, uregs))
+ return -EFAULT;
+ 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,