[PATCH V3 2/2] Move stack parameters for sed_ioctl to prevent oversized stack with CONFIG_KASAN

From: Scott Bauer
Date: Thu Feb 09 2017 - 12:32:23 EST


When CONFIG_KASAN is enabled, compilation fails:

block/sed-opal.c: In function 'sed_ioctl':
block/sed-opal.c:2447:1: error: the frame size of 2256 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]

Moved all the ioctl structures off the stack and dynamically activate
using _IOC_SIZE()

Fixes: 455a7b238cd6 ("block: Add Sed-opal library")

Reported-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Scott Bauer <scott.bauer@xxxxxxxxx>
---
block/sed-opal.c | 134 +++++++++++++++++++++----------------------------------
1 file changed, 50 insertions(+), 84 deletions(-)

diff --git a/block/sed-opal.c b/block/sed-opal.c
index bf1406e..4985d95 100644
--- a/block/sed-opal.c
+++ b/block/sed-opal.c
@@ -2346,7 +2346,10 @@ EXPORT_SYMBOL(opal_unlock_from_suspend);

int sed_ioctl(struct opal_dev *dev, unsigned int cmd, unsigned long ptr)
{
+ void *ioctl_ptr;
+ int ret = -ENOTTY;
void __user *arg = (void __user *)ptr;
+ unsigned int cmd_size = _IOC_SIZE(cmd);

if (!capable(CAP_SYS_ADMIN))
return -EACCES;
@@ -2355,94 +2358,57 @@ int sed_ioctl(struct opal_dev *dev, unsigned int cmd, unsigned long ptr)
return -ENOTSUPP;
}

- switch (cmd) {
- case IOC_OPAL_SAVE: {
- struct opal_lock_unlock lk_unlk;
-
- if (copy_from_user(&lk_unlk, arg, sizeof(lk_unlk)))
- return -EFAULT;
- return opal_save(dev, &lk_unlk);
- }
- case IOC_OPAL_LOCK_UNLOCK: {
- struct opal_lock_unlock lk_unlk;
-
- if (copy_from_user(&lk_unlk, arg, sizeof(lk_unlk)))
- return -EFAULT;
- return opal_lock_unlock(dev, &lk_unlk);
- }
- case IOC_OPAL_TAKE_OWNERSHIP: {
- struct opal_key opal_key;
-
- if (copy_from_user(&opal_key, arg, sizeof(opal_key)))
- return -EFAULT;
- return opal_take_ownership(dev, &opal_key);
- }
- case IOC_OPAL_ACTIVATE_LSP: {
- struct opal_lr_act opal_lr_act;
-
- if (copy_from_user(&opal_lr_act, arg, sizeof(opal_lr_act)))
- return -EFAULT;
- return opal_activate_lsp(dev, &opal_lr_act);
- }
- case IOC_OPAL_SET_PW: {
- struct opal_new_pw opal_pw;
-
- if (copy_from_user(&opal_pw, arg, sizeof(opal_pw)))
- return -EFAULT;
- return opal_set_new_pw(dev, &opal_pw);
- }
- case IOC_OPAL_ACTIVATE_USR: {
- struct opal_session_info session;
-
- if (copy_from_user(&session, arg, sizeof(session)))
- return -EFAULT;
- return opal_activate_user(dev, &session);
- }
- case IOC_OPAL_REVERT_TPR: {
- struct opal_key opal_key;
-
- if (copy_from_user(&opal_key, arg, sizeof(opal_key)))
- return -EFAULT;
- return opal_reverttper(dev, &opal_key);
- }
- case IOC_OPAL_LR_SETUP: {
- struct opal_user_lr_setup lrs;
-
- if (copy_from_user(&lrs, arg, sizeof(lrs)))
- return -EFAULT;
- return opal_setup_locking_range(dev, &lrs);
- }
- case IOC_OPAL_ADD_USR_TO_LR: {
- struct opal_lock_unlock lk_unlk;
-
- if (copy_from_user(&lk_unlk, arg, sizeof(lk_unlk)))
- return -EFAULT;
- return opal_add_user_to_lr(dev, &lk_unlk);
- }
- case IOC_OPAL_ENABLE_DISABLE_MBR: {
- struct opal_mbr_data mbr;
-
- if (copy_from_user(&mbr, arg, sizeof(mbr)))
- return -EFAULT;
- return opal_enable_disable_shadow_mbr(dev, &mbr);
- }
- case IOC_OPAL_ERASE_LR: {
- struct opal_session_info session;
-
- if (copy_from_user(&session, arg, sizeof(session)))
- return -EFAULT;
- return opal_erase_locking_range(dev, &session);
+ ioctl_ptr = kzalloc(cmd_size, GFP_KERNEL);
+ if (!ioctl_ptr)
+ return -ENOMEM;
+ if (copy_from_user(ioctl_ptr, arg, cmd_size)) {
+ ret = -EFAULT;
+ goto out;
}
- case IOC_OPAL_SECURE_ERASE_LR: {
- struct opal_session_info session;

- if (copy_from_user(&session, arg, sizeof(session)))
- return -EFAULT;
- return opal_secure_erase_locking_range(dev, &session);
- }
+ switch (cmd) {
+ case IOC_OPAL_SAVE:
+ ret = opal_save(dev, ioctl_ptr);
+ break;
+ case IOC_OPAL_LOCK_UNLOCK:
+ ret = opal_lock_unlock(dev, ioctl_ptr);
+ break;
+ case IOC_OPAL_TAKE_OWNERSHIP:
+ ret = opal_take_ownership(dev, ioctl_ptr);
+ break;
+ case IOC_OPAL_ACTIVATE_LSP:
+ ret = opal_activate_lsp(dev, ioctl_ptr);
+ break;
+ case IOC_OPAL_SET_PW:
+ ret = opal_set_new_pw(dev, ioctl_ptr);
+ break;
+ case IOC_OPAL_ACTIVATE_USR:
+ ret = opal_activate_user(dev, ioctl_ptr);
+ break;
+ case IOC_OPAL_REVERT_TPR:
+ ret = opal_reverttper(dev, ioctl_ptr);
+ break;
+ case IOC_OPAL_LR_SETUP:
+ ret = opal_setup_locking_range(dev, ioctl_ptr);
+ break;
+ case IOC_OPAL_ADD_USR_TO_LR:
+ ret = opal_add_user_to_lr(dev, ioctl_ptr);
+ break;
+ case IOC_OPAL_ENABLE_DISABLE_MBR:
+ ret = opal_enable_disable_shadow_mbr(dev, ioctl_ptr);
+ break;
+ case IOC_OPAL_ERASE_LR:
+ ret = opal_erase_locking_range(dev, ioctl_ptr);
+ break;
+ case IOC_OPAL_SECURE_ERASE_LR:
+ ret = opal_secure_erase_locking_range(dev, ioctl_ptr);
+ break;
default:
pr_warn("No such Opal Ioctl %u\n", cmd);
}
- return -ENOTTY;
+
+out:
+ kfree(ioctl_ptr);
+ return ret;
}
EXPORT_SYMBOL_GPL(sed_ioctl);
--
2.7.4