Re: [PATCH x86 for review II] [26/39] i386: fix 32-bit ioctls on x64_32

Giuliano Procida
2007-02-12T13:24:33Z

This is a nicer version of the MTRR compatibilty ioctl patch, compiles
smaller and also tested.

Signed-off-by: Giuliano Procida <giuliano.procida@googlemail.com>

--- linux-source-2.6.19.1.orig/arch/i386/kernel/cpu/mtrr/if.c 2006-12-11
19:32:53.000000000 +0000
+++ linux-source-2.6.19.1/arch/i386/kernel/cpu/mtrr/if.c 2007-01-27
12:25:21.000000000 +0000
@@ -154,150 +154,164 @@
mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
{
int err = 0;
+ const unsigned ioctl_type = _IOC_TYPE(cmd);
+ const unsigned ioctl_dir = _IOC_DIR(cmd);
+ const unsigned ioctl_nr = _IOC_NR(cmd);
+ const unsigned ioctl_size = _IOC_SIZE(cmd);
mtrr_type type;
- struct mtrr_sentry sentry;
- struct mtrr_gentry gentry;
+ union mtrr_data {
+ struct mtrr_sentry sentry;
+ struct mtrr_gentry gentry;
+#ifdef CONFIG_COMPAT
+ struct mtrr_sentry32 sentry32;
+ struct mtrr_gentry32 gentry32;
+#endif
+ } u;
void __user *arg = (void __user *) __arg;

- switch (cmd) {
- case MTRRIOC_ADD_ENTRY:
- case MTRRIOC_SET_ENTRY:
- case MTRRIOC_DEL_ENTRY:
- case MTRRIOC_KILL_ENTRY:
- case MTRRIOC_ADD_PAGE_ENTRY:
- case MTRRIOC_SET_PAGE_ENTRY:
- case MTRRIOC_DEL_PAGE_ENTRY:
- case MTRRIOC_KILL_PAGE_ENTRY:
- if (copy_from_user(&sentry, arg, sizeof sentry))
- return -EFAULT;
- break;
- case MTRRIOC_GET_ENTRY:
- case MTRRIOC_GET_PAGE_ENTRY:
- if (copy_from_user(&gentry, arg, sizeof gentry))
- return -EFAULT;
+ /* check type and max size */
+ if (ioctl_type != MTRR_IOCTL_BASE || ioctl_size > sizeof(u))
+ return -ENOTTY;
+
+ /* copy from user */
+ if (ioctl_dir & _IOC_WRITE && copy_from_user(&u, arg, ioctl_size))
+ return -EFAULT;
+
+ /* check number, direction, size and permission */
+ switch (ioctl_nr) {
+ case _IOC_NR(MTRRIOC_ADD_ENTRY):
+ case _IOC_NR(MTRRIOC_SET_ENTRY):
+ case _IOC_NR(MTRRIOC_DEL_ENTRY):
+ case _IOC_NR(MTRRIOC_KILL_ENTRY):
+ case _IOC_NR(MTRRIOC_ADD_PAGE_ENTRY):
+ case _IOC_NR(MTRRIOC_SET_PAGE_ENTRY):
+ case _IOC_NR(MTRRIOC_DEL_PAGE_ENTRY):
+ case _IOC_NR(MTRRIOC_KILL_PAGE_ENTRY):
+ if (ioctl_dir != _IOC_WRITE)
+ return -ENOTTY;
+ switch (ioctl_size) {
+ case sizeof(struct mtrr_sentry):
break;
#ifdef CONFIG_COMPAT
- case MTRRIOC32_ADD_ENTRY:
- case MTRRIOC32_SET_ENTRY:
- case MTRRIOC32_DEL_ENTRY:
- case MTRRIOC32_KILL_ENTRY:
- case MTRRIOC32_ADD_PAGE_ENTRY:
- case MTRRIOC32_SET_PAGE_ENTRY:
- case MTRRIOC32_DEL_PAGE_ENTRY:
- case MTRRIOC32_KILL_PAGE_ENTRY: {
- struct mtrr_sentry32 __user *s32 = (struct mtrr_sentry32 __user *)__arg;
- err = get_user(sentry.base, &s32->base);
- err |= get_user(sentry.size, &s32->size);
- err |= get_user(sentry.type, &s32->type);
- if (err)
- return err;
- break;
- }
- case MTRRIOC32_GET_ENTRY:
- case MTRRIOC32_GET_PAGE_ENTRY: {
- struct mtrr_gentry32 __user *g32 = (struct mtrr_gentry32 __user *)__arg;
- err = get_user(gentry.regnum, &g32->regnum);
- err |= get_user(gentry.base, &g32->base);
- err |= get_user(gentry.size, &g32->size);
- err |= get_user(gentry.type, &g32->type);
- if (err)
- return err;
+ case sizeof(struct mtrr_sentry32):
+ {
+ struct mtrr_sentry32 s32 = u.sentry32;
+ u.sentry.base = s32.base;
+ u.sentry.size = s32.size;
+ u.sentry.type = s32.type;
+ }
break;
- }
#endif
+ default:
+ return -ENOTTY;
+ }
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ break;
+ case _IOC_NR(MTRRIOC_GET_ENTRY):
+ case _IOC_NR(MTRRIOC_GET_PAGE_ENTRY):
+ if (ioctl_dir != (_IOC_READ|_IOC_WRITE))
+ return -ENOTTY;
+ switch (ioctl_size) {
+ case sizeof(struct mtrr_gentry):
+ break;
+#ifdef CONFIG_COMPAT
+ case sizeof(struct mtrr_gentry32):
+ {
+ struct mtrr_gentry32 g32 = u.gentry32;
+ u.gentry.base = g32.base;
+ u.gentry.size = g32.size;
+ u.gentry.regnum = g32.regnum;
+ u.gentry.type = g32.type;
+ }
+ break;
+#endif
+ default:
+ return -ENOTTY;
+ }
+ break;
+ default:
+ return -ENOTTY;
}

- switch (cmd) {
+ /* perform command */
+ switch (ioctl_nr) {
default:
return -ENOTTY;
- case MTRRIOC_ADD_ENTRY:
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
+ case _IOC_NR(MTRRIOC_ADD_ENTRY):
err =
- mtrr_file_add(sentry.base, sentry.size, sentry.type, 1,
+ mtrr_file_add(u.sentry.base, u.sentry.size, u.sentry.type, 1,
file, 0);
break;
- case MTRRIOC_SET_ENTRY:
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- err = mtrr_add(sentry.base, sentry.size, sentry.type, 0);
+ case _IOC_NR(MTRRIOC_SET_ENTRY):
+ err = mtrr_add(u.sentry.base, u.sentry.size, u.sentry.type, 0);
break;
- case MTRRIOC_DEL_ENTRY:
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- err = mtrr_file_del(sentry.base, sentry.size, file, 0);
+ case _IOC_NR(MTRRIOC_DEL_ENTRY):
+ err = mtrr_file_del(u.sentry.base, u.sentry.size, file, 0);
break;
- case MTRRIOC_KILL_ENTRY:
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- err = mtrr_del(-1, sentry.base, sentry.size);
+ case _IOC_NR(MTRRIOC_KILL_ENTRY):
+ err = mtrr_del(-1, u.sentry.base, u.sentry.size);
break;
- case MTRRIOC_GET_ENTRY:
- if (gentry.regnum >= num_var_ranges)
+ case _IOC_NR(MTRRIOC_GET_ENTRY):
+ if (u.gentry.regnum >= num_var_ranges)
return -EINVAL;
- mtrr_if->get(gentry.regnum, &gentry.base, &gentry.size, &type);
+ mtrr_if->get(u.gentry.regnum, &u.gentry.base, &u.gentry.size, &type);

/* Hide entries that go above 4GB */
- if (gentry.base + gentry.size > 0x100000
- || gentry.size == 0x100000)
- gentry.base = gentry.size = gentry.type = 0;
+ if (u.gentry.base + u.gentry.size > 0x100000
+ || u.gentry.size == 0x100000)
+ u.gentry.base = u.gentry.size = u.gentry.type = 0;
else {
- gentry.base <<= PAGE_SHIFT;
- gentry.size <<= PAGE_SHIFT;
- gentry.type = type;
+ u.gentry.base <<= PAGE_SHIFT;
+ u.gentry.size <<= PAGE_SHIFT;
+ u.gentry.type = type;
}

break;
- case MTRRIOC_ADD_PAGE_ENTRY:
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
+ case _IOC_NR(MTRRIOC_ADD_PAGE_ENTRY):
err =
- mtrr_file_add(sentry.base, sentry.size, sentry.type, 1,
+ mtrr_file_add(u.sentry.base, u.sentry.size, u.sentry.type, 1,
file, 1);
break;
- case MTRRIOC_SET_PAGE_ENTRY:
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- err = mtrr_add_page(sentry.base, sentry.size, sentry.type, 0);
+ case _IOC_NR(MTRRIOC_SET_PAGE_ENTRY):
+ err = mtrr_add_page(u.sentry.base, u.sentry.size, u.sentry.type, 0);
break;
- case MTRRIOC_DEL_PAGE_ENTRY:
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- err = mtrr_file_del(sentry.base, sentry.size, file, 1);
+ case _IOC_NR(MTRRIOC_DEL_PAGE_ENTRY):
+ err = mtrr_file_del(u.sentry.base, u.sentry.size, file, 1);
break;
- case MTRRIOC_KILL_PAGE_ENTRY:
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- err = mtrr_del_page(-1, sentry.base, sentry.size);
+ case _IOC_NR(MTRRIOC_KILL_PAGE_ENTRY):
+ err = mtrr_del_page(-1, u.sentry.base, u.sentry.size);
break;
- case MTRRIOC_GET_PAGE_ENTRY:
- if (gentry.regnum >= num_var_ranges)
+ case _IOC_NR(MTRRIOC_GET_PAGE_ENTRY):
+ if (u.gentry.regnum >= num_var_ranges)
return -EINVAL;
- mtrr_if->get(gentry.regnum, &gentry.base, &gentry.size, &type);
- gentry.type = type;
+ mtrr_if->get(u.gentry.regnum, &u.gentry.base, &u.gentry.size, &type);
+ u.gentry.type = type;
break;
}

if (err)
return err;

- switch(cmd) {
- case MTRRIOC_GET_ENTRY:
- case MTRRIOC_GET_PAGE_ENTRY:
- if (copy_to_user(arg, &gentry, sizeof gentry))
- err = -EFAULT;
- break;
+ /* copy to user */
+ if (ioctl_dir & _IOC_READ) {
+ switch (ioctl_size) {
#ifdef CONFIG_COMPAT
- case MTRRIOC32_GET_ENTRY:
- case MTRRIOC32_GET_PAGE_ENTRY: {
- struct mtrr_gentry32 __user *g32 = (struct mtrr_gentry32 __user *)__arg;
- err = put_user(gentry.base, &g32->base);
- err |= put_user(gentry.size, &g32->size);
- err |= put_user(gentry.regnum, &g32->regnum);
- err |= put_user(gentry.type, &g32->type);
+ case sizeof(struct mtrr_gentry32):
+ {
+ struct mtrr_gentry g64 = u.gentry;
+ u.gentry32.base = g64.base;
+ u.gentry32.size = g64.size;
+ u.gentry32.regnum = g64.regnum;
+ u.gentry32.type = g64.type;
+ }
break;
- }
#endif
+ default:
+ break;
+ }
+ if (copy_to_user(arg, &u, ioctl_size))
+ err = -EFAULT;
}
return err;
}