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[SCSI] target: fix use after free detected by SLUB poison
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This patch moves a large number of memory release paths inside of the
configfs callback target_core_hba_item_ops->release() called from
within fs/configfs/item.c: config_item_cleanup() context.  This patch
resolves the SLUB 'Poison overwritten' warnings.

Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
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Nicholas Bellinger authored and James Bottomley committed Feb 12, 2011
1 parent e89d15e commit 1f6fe7c
Showing 3 changed files with 140 additions and 73 deletions.
120 changes: 74 additions & 46 deletions drivers/target/target_core_configfs.c
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Original file line number Diff line number Diff line change
@@ -1970,13 +1970,35 @@ static void target_core_dev_release(struct config_item *item)
{
struct se_subsystem_dev *se_dev = container_of(to_config_group(item),
struct se_subsystem_dev, se_dev_group);
struct config_group *dev_cg;

if (!(se_dev))
return;
struct se_hba *hba = item_to_hba(&se_dev->se_dev_hba->hba_group.cg_item);
struct se_subsystem_api *t = hba->transport;
struct config_group *dev_cg = &se_dev->se_dev_group;

dev_cg = &se_dev->se_dev_group;
kfree(dev_cg->default_groups);
/*
* This pointer will set when the storage is enabled with:
*`echo 1 > $CONFIGFS/core/$HBA/$DEV/dev_enable`
*/
if (se_dev->se_dev_ptr) {
printk(KERN_INFO "Target_Core_ConfigFS: Calling se_free_"
"virtual_device() for se_dev_ptr: %p\n",
se_dev->se_dev_ptr);

se_free_virtual_device(se_dev->se_dev_ptr, hba);
} else {
/*
* Release struct se_subsystem_dev->se_dev_su_ptr..
*/
printk(KERN_INFO "Target_Core_ConfigFS: Calling t->free_"
"device() for se_dev_su_ptr: %p\n",
se_dev->se_dev_su_ptr);

t->free_device(se_dev->se_dev_su_ptr);
}

printk(KERN_INFO "Target_Core_ConfigFS: Deallocating se_subsystem"
"_dev_t: %p\n", se_dev);
kfree(se_dev);
}

static ssize_t target_core_dev_show(struct config_item *item,
@@ -2139,7 +2161,16 @@ static struct configfs_attribute *target_core_alua_lu_gp_attrs[] = {
NULL,
};

static void target_core_alua_lu_gp_release(struct config_item *item)
{
struct t10_alua_lu_gp *lu_gp = container_of(to_config_group(item),
struct t10_alua_lu_gp, lu_gp_group);

core_alua_free_lu_gp(lu_gp);
}

static struct configfs_item_operations target_core_alua_lu_gp_ops = {
.release = target_core_alua_lu_gp_release,
.show_attribute = target_core_alua_lu_gp_attr_show,
.store_attribute = target_core_alua_lu_gp_attr_store,
};
@@ -2190,9 +2221,11 @@ static void target_core_alua_drop_lu_gp(
printk(KERN_INFO "Target_Core_ConfigFS: Releasing ALUA Logical Unit"
" Group: core/alua/lu_gps/%s, ID: %hu\n",
config_item_name(item), lu_gp->lu_gp_id);

/*
* core_alua_free_lu_gp() is called from target_core_alua_lu_gp_ops->release()
* -> target_core_alua_lu_gp_release()
*/
config_item_put(item);
core_alua_free_lu_gp(lu_gp);
}

static struct configfs_group_operations target_core_alua_lu_gps_group_ops = {
@@ -2548,7 +2581,16 @@ static struct configfs_attribute *target_core_alua_tg_pt_gp_attrs[] = {
NULL,
};

static void target_core_alua_tg_pt_gp_release(struct config_item *item)
{
struct t10_alua_tg_pt_gp *tg_pt_gp = container_of(to_config_group(item),
struct t10_alua_tg_pt_gp, tg_pt_gp_group);

core_alua_free_tg_pt_gp(tg_pt_gp);
}

static struct configfs_item_operations target_core_alua_tg_pt_gp_ops = {
.release = target_core_alua_tg_pt_gp_release,
.show_attribute = target_core_alua_tg_pt_gp_attr_show,
.store_attribute = target_core_alua_tg_pt_gp_attr_store,
};
@@ -2601,9 +2643,11 @@ static void target_core_alua_drop_tg_pt_gp(
printk(KERN_INFO "Target_Core_ConfigFS: Releasing ALUA Target Port"
" Group: alua/tg_pt_gps/%s, ID: %hu\n",
config_item_name(item), tg_pt_gp->tg_pt_gp_id);

/*
* core_alua_free_tg_pt_gp() is called from target_core_alua_tg_pt_gp_ops->release()
* -> target_core_alua_tg_pt_gp_release().
*/
config_item_put(item);
core_alua_free_tg_pt_gp(tg_pt_gp);
}

static struct configfs_group_operations target_core_alua_tg_pt_gps_group_ops = {
@@ -2770,13 +2814,11 @@ static void target_core_drop_subdev(
struct se_subsystem_api *t;
struct config_item *df_item;
struct config_group *dev_cg, *tg_pt_gp_cg;
int i, ret;
int i;

hba = item_to_hba(&se_dev->se_dev_hba->hba_group.cg_item);

if (mutex_lock_interruptible(&hba->hba_access_mutex))
goto out;

mutex_lock(&hba->hba_access_mutex);
t = hba->transport;

spin_lock(&se_global->g_device_lock);
@@ -2790,7 +2832,10 @@ static void target_core_drop_subdev(
config_item_put(df_item);
}
kfree(tg_pt_gp_cg->default_groups);
core_alua_free_tg_pt_gp(T10_ALUA(se_dev)->default_tg_pt_gp);
/*
* core_alua_free_tg_pt_gp() is called from ->default_tg_pt_gp
* directly from target_core_alua_tg_pt_gp_release().
*/
T10_ALUA(se_dev)->default_tg_pt_gp = NULL;

dev_cg = &se_dev->se_dev_group;
@@ -2799,38 +2844,12 @@ static void target_core_drop_subdev(
dev_cg->default_groups[i] = NULL;
config_item_put(df_item);
}

config_item_put(item);
/*
* This pointer will set when the storage is enabled with:
* `echo 1 > $CONFIGFS/core/$HBA/$DEV/dev_enable`
* The releasing of se_dev and associated se_dev->se_dev_ptr is done
* from target_core_dev_item_ops->release() ->target_core_dev_release().
*/
if (se_dev->se_dev_ptr) {
printk(KERN_INFO "Target_Core_ConfigFS: Calling se_free_"
"virtual_device() for se_dev_ptr: %p\n",
se_dev->se_dev_ptr);

ret = se_free_virtual_device(se_dev->se_dev_ptr, hba);
if (ret < 0)
goto hba_out;
} else {
/*
* Release struct se_subsystem_dev->se_dev_su_ptr..
*/
printk(KERN_INFO "Target_Core_ConfigFS: Calling t->free_"
"device() for se_dev_su_ptr: %p\n",
se_dev->se_dev_su_ptr);

t->free_device(se_dev->se_dev_su_ptr);
}

printk(KERN_INFO "Target_Core_ConfigFS: Deallocating se_subsystem"
"_dev_t: %p\n", se_dev);

hba_out:
config_item_put(item);
mutex_unlock(&hba->hba_access_mutex);
out:
kfree(se_dev);
}

static struct configfs_group_operations target_core_hba_group_ops = {
@@ -2913,13 +2932,21 @@ SE_HBA_ATTR(hba_mode, S_IRUGO | S_IWUSR);

CONFIGFS_EATTR_OPS(target_core_hba, se_hba, hba_group);

static void target_core_hba_release(struct config_item *item)
{
struct se_hba *hba = container_of(to_config_group(item),
struct se_hba, hba_group);
core_delete_hba(hba);
}

static struct configfs_attribute *target_core_hba_attrs[] = {
&target_core_hba_hba_info.attr,
&target_core_hba_hba_mode.attr,
NULL,
};

static struct configfs_item_operations target_core_hba_item_ops = {
.release = target_core_hba_release,
.show_attribute = target_core_hba_attr_show,
.store_attribute = target_core_hba_attr_store,
};
@@ -2996,10 +3023,11 @@ static void target_core_call_delhbafromtarget(
struct config_group *group,
struct config_item *item)
{
struct se_hba *hba = item_to_hba(item);

/*
* core_delete_hba() is called from target_core_hba_item_ops->release()
* -> target_core_hba_release()
*/
config_item_put(item);
core_delete_hba(hba);
}

static struct configfs_group_operations target_core_group_ops = {
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