[MTD] mtdchar.c: Fix regression in MEMGETREGIONINFO ioctl()
The MEMGETREGIONINFO ioctl() in mtdchar.c was clobbering user memory by
overwriting more than intended, due the size of struct mtd_erase_region_info
changing in commit 0ecbc81adfcb9f15f86b05ff576b342ce81bbef8 ('Support
for auto locking flash on power up').
Fix avoids this by copying struct members one by one with put_user(), as there
is no longer a convenient struct to use the size of as the length argument to
copy_to_user().
Signed-off-by: Zev Weiss <zevweiss@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index d2f3318..e00d424 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -410,16 +410,20 @@
case MEMGETREGIONINFO:
{
- struct region_info_user ur;
+ uint32_t ur_idx;
+ struct mtd_erase_region_info *kr;
+ struct region_info_user *ur = (struct region_info_user *) argp;
- if (copy_from_user(&ur, argp, sizeof(struct region_info_user)))
+ if (get_user(ur_idx, &(ur->regionindex)))
return -EFAULT;
- if (ur.regionindex >= mtd->numeraseregions)
- return -EINVAL;
- if (copy_to_user(argp, &(mtd->eraseregions[ur.regionindex]),
- sizeof(struct mtd_erase_region_info)))
+ kr = &(mtd->eraseregions[ur_idx]);
+
+ if (put_user(kr->offset, &(ur->offset))
+ || put_user(kr->erasesize, &(ur->erasesize))
+ || put_user(kr->numblocks, &(ur->numblocks)))
return -EFAULT;
+
break;
}