Fix unprotected zfs_znode_dmu_fini

In original code, zfs_znode_dmu_fini is called in zfs_rmnode without
zfs_znode_hold_enter. It seems to assume it's ok to do so when the znode
is unlinked. However this assumption is not correct, as zfs_zget can be
called by NFS through zpl_fh_to_dentry as pointed out by Christian in
https://github.com/openzfs/zfs/pull/12767, which could result in a
use-after-free bug.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Chunwei Chen <david.chen@nutanix.com>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #12767 
Closes #14364
This commit is contained in:
Chunwei Chen 2023-01-19 16:59:05 -08:00 committed by GitHub
parent a379083d9f
commit c6dab6dd39
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5 changed files with 20 additions and 5 deletions

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@ -272,6 +272,8 @@ extern int zfs_freesp(znode_t *, uint64_t, uint64_t, int, boolean_t);
extern void zfs_znode_init(void);
extern void zfs_znode_fini(void);
extern int zfs_znode_hold_compare(const void *, const void *);
extern znode_hold_t *zfs_znode_hold_enter(zfsvfs_t *, uint64_t);
extern void zfs_znode_hold_exit(zfsvfs_t *, znode_hold_t *);
extern int zfs_zget(zfsvfs_t *, uint64_t, znode_t **);
extern int zfs_rezget(znode_t *);
extern void zfs_zinactive(znode_t *);

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@ -426,6 +426,7 @@ zfs_rmnode(znode_t *zp)
zfsvfs_t *zfsvfs = zp->z_zfsvfs;
objset_t *os = zfsvfs->z_os;
dmu_tx_t *tx;
uint64_t z_id = zp->z_id;
uint64_t acl_obj;
uint64_t xattr_obj;
uint64_t count;
@ -445,8 +446,10 @@ zfs_rmnode(znode_t *zp)
* Not enough space to delete some xattrs.
* Leave it in the unlinked set.
*/
ZFS_OBJ_HOLD_ENTER(zfsvfs, z_id);
zfs_znode_dmu_fini(zp);
zfs_znode_free(zp);
ZFS_OBJ_HOLD_EXIT(zfsvfs, z_id);
return;
}
} else {
@ -464,8 +467,10 @@ zfs_rmnode(znode_t *zp)
* Not enough space or we were interrupted by unmount.
* Leave the file in the unlinked set.
*/
ZFS_OBJ_HOLD_ENTER(zfsvfs, z_id);
zfs_znode_dmu_fini(zp);
zfs_znode_free(zp);
ZFS_OBJ_HOLD_EXIT(zfsvfs, z_id);
return;
}
}
@ -501,8 +506,10 @@ zfs_rmnode(znode_t *zp)
* which point we'll call zfs_unlinked_drain() to process it).
*/
dmu_tx_abort(tx);
ZFS_OBJ_HOLD_ENTER(zfsvfs, z_id);
zfs_znode_dmu_fini(zp);
zfs_znode_free(zp);
ZFS_OBJ_HOLD_EXIT(zfsvfs, z_id);
return;
}

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@ -386,7 +386,6 @@ void
zfs_znode_dmu_fini(znode_t *zp)
{
ASSERT(MUTEX_HELD(ZFS_OBJ_MUTEX(zp->z_zfsvfs, zp->z_id)) ||
zp->z_unlinked ||
ZFS_TEARDOWN_INACTIVE_WRITE_HELD(zp->z_zfsvfs));
sa_handle_destroy(zp->z_sa_hdl);

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@ -649,6 +649,8 @@ zfs_rmnode(znode_t *zp)
objset_t *os = zfsvfs->z_os;
znode_t *xzp = NULL;
dmu_tx_t *tx;
znode_hold_t *zh;
uint64_t z_id = zp->z_id;
uint64_t acl_obj;
uint64_t xattr_obj;
uint64_t links;
@ -666,8 +668,9 @@ zfs_rmnode(znode_t *zp)
* Not enough space to delete some xattrs.
* Leave it in the unlinked set.
*/
zh = zfs_znode_hold_enter(zfsvfs, z_id);
zfs_znode_dmu_fini(zp);
zfs_znode_hold_exit(zfsvfs, zh);
return;
}
}
@ -686,7 +689,9 @@ zfs_rmnode(znode_t *zp)
* Not enough space or we were interrupted by unmount.
* Leave the file in the unlinked set.
*/
zh = zfs_znode_hold_enter(zfsvfs, z_id);
zfs_znode_dmu_fini(zp);
zfs_znode_hold_exit(zfsvfs, zh);
return;
}
}
@ -726,7 +731,9 @@ zfs_rmnode(znode_t *zp)
* which point we'll call zfs_unlinked_drain() to process it).
*/
dmu_tx_abort(tx);
zh = zfs_znode_hold_enter(zfsvfs, z_id);
zfs_znode_dmu_fini(zp);
zfs_znode_hold_exit(zfsvfs, zh);
goto out;
}

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@ -271,7 +271,7 @@ zfs_znode_held(zfsvfs_t *zfsvfs, uint64_t obj)
return (held);
}
static znode_hold_t *
znode_hold_t *
zfs_znode_hold_enter(zfsvfs_t *zfsvfs, uint64_t obj)
{
znode_hold_t *zh, *zh_new, search;
@ -304,7 +304,7 @@ zfs_znode_hold_enter(zfsvfs_t *zfsvfs, uint64_t obj)
return (zh);
}
static void
void
zfs_znode_hold_exit(zfsvfs_t *zfsvfs, znode_hold_t *zh)
{
int i = ZFS_OBJ_HASH(zfsvfs, zh->zh_obj);
@ -357,7 +357,7 @@ zfs_znode_sa_init(zfsvfs_t *zfsvfs, znode_t *zp,
void
zfs_znode_dmu_fini(znode_t *zp)
{
ASSERT(zfs_znode_held(ZTOZSB(zp), zp->z_id) || zp->z_unlinked ||
ASSERT(zfs_znode_held(ZTOZSB(zp), zp->z_id) ||
RW_WRITE_HELD(&ZTOZSB(zp)->z_teardown_inactive_lock));
sa_handle_destroy(zp->z_sa_hdl);