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mirror_zfs/module/zfs/zfs_sa.c
Ned Bass 43b4935e53 Prevent SA length overflow 
The function sa_update() accepts a 32-bit length parameter and
assigns it to a 16-bit field in sa_bulk_attr_t, potentially
truncating the passed-in value. This could lead to corrupt system
attribute (SA) records getting written to the pool. Add a VERIFY to
sa_update() to detect cases where overflow would occur. The SA length
is limited to 16-bit values by the on-disk format defined by
sa_hdr_phys_t.

The function zfs_sa_set_xattr() is vulnerable to this bug if the
unpacked nvlist of xattrs is less than 64k in size but the packed
size is greater than 64k. Fix this by appropriately checking the
size of the packed nvlist before calling sa_update(). Add error
handling to zpl_xattr_set_sa() to keep the cached list of SA-based
xattrs consistent with the data on disk.

Lastly, zfs_sa_set_xattr() calls dmu_tx_abort() on an assigned
transaction if sa_update() returns an error, but the DMU only allows
unassigned transactions to be aborted. Wrap the sa_update() call in a
VERIFY0, remove the transaction abort, and call dmu_tx_commit()
unconditionally. This is consistent practice with other callers
of sa_update().

Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Closes #4150
2015-12-30 13:20:12 -08:00

424 lines
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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
*/
#include <sys/zfs_context.h>
#include <sys/vnode.h>
#include <sys/sa.h>
#include <sys/zfs_acl.h>
#include <sys/zfs_sa.h>
/*
* ZPL attribute registration table.
* Order of attributes doesn't matter
* a unique value will be assigned for each
* attribute that is file system specific
*
* This is just the set of ZPL attributes that this
* version of ZFS deals with natively. The file system
* could have other attributes stored in files, but they will be
* ignored. The SA framework will preserve them, just that
* this version of ZFS won't change or delete them.
*/
sa_attr_reg_t zfs_attr_table[ZPL_END+1] = {
{"ZPL_ATIME", sizeof (uint64_t) * 2, SA_UINT64_ARRAY, 0},
{"ZPL_MTIME", sizeof (uint64_t) * 2, SA_UINT64_ARRAY, 1},
{"ZPL_CTIME", sizeof (uint64_t) * 2, SA_UINT64_ARRAY, 2},
{"ZPL_CRTIME", sizeof (uint64_t) * 2, SA_UINT64_ARRAY, 3},
{"ZPL_GEN", sizeof (uint64_t), SA_UINT64_ARRAY, 4},
{"ZPL_MODE", sizeof (uint64_t), SA_UINT64_ARRAY, 5},
{"ZPL_SIZE", sizeof (uint64_t), SA_UINT64_ARRAY, 6},
{"ZPL_PARENT", sizeof (uint64_t), SA_UINT64_ARRAY, 7},
{"ZPL_LINKS", sizeof (uint64_t), SA_UINT64_ARRAY, 8},
{"ZPL_XATTR", sizeof (uint64_t), SA_UINT64_ARRAY, 9},
{"ZPL_RDEV", sizeof (uint64_t), SA_UINT64_ARRAY, 10},
{"ZPL_FLAGS", sizeof (uint64_t), SA_UINT64_ARRAY, 11},
{"ZPL_UID", sizeof (uint64_t), SA_UINT64_ARRAY, 12},
{"ZPL_GID", sizeof (uint64_t), SA_UINT64_ARRAY, 13},
{"ZPL_PAD", sizeof (uint64_t) * 4, SA_UINT64_ARRAY, 14},
{"ZPL_ZNODE_ACL", 88, SA_UINT8_ARRAY, 15},
{"ZPL_DACL_COUNT", sizeof (uint64_t), SA_UINT64_ARRAY, 0},
{"ZPL_SYMLINK", 0, SA_UINT8_ARRAY, 0},
{"ZPL_SCANSTAMP", 32, SA_UINT8_ARRAY, 0},
{"ZPL_DACL_ACES", 0, SA_ACL, 0},
{"ZPL_DXATTR", 0, SA_UINT8_ARRAY, 0},
{NULL, 0, 0, 0}
};
#ifdef _KERNEL
int
zfs_sa_readlink(znode_t *zp, uio_t *uio)
{
dmu_buf_t *db = sa_get_db(zp->z_sa_hdl);
size_t bufsz;
int error;
bufsz = zp->z_size;
if (bufsz + ZFS_OLD_ZNODE_PHYS_SIZE <= db->db_size) {
error = uiomove((caddr_t)db->db_data +
ZFS_OLD_ZNODE_PHYS_SIZE,
MIN((size_t)bufsz, uio->uio_resid), UIO_READ, uio);
} else {
dmu_buf_t *dbp;
if ((error = dmu_buf_hold(ZTOZSB(zp)->z_os, zp->z_id,
0, FTAG, &dbp, DMU_READ_NO_PREFETCH)) == 0) {
error = uiomove(dbp->db_data,
MIN((size_t)bufsz, uio->uio_resid), UIO_READ, uio);
dmu_buf_rele(dbp, FTAG);
}
}
return (error);
}
void
zfs_sa_symlink(znode_t *zp, char *link, int len, dmu_tx_t *tx)
{
dmu_buf_t *db = sa_get_db(zp->z_sa_hdl);
if (ZFS_OLD_ZNODE_PHYS_SIZE + len <= dmu_bonus_max()) {
VERIFY(dmu_set_bonus(db,
len + ZFS_OLD_ZNODE_PHYS_SIZE, tx) == 0);
if (len) {
bcopy(link, (caddr_t)db->db_data +
ZFS_OLD_ZNODE_PHYS_SIZE, len);
}
} else {
dmu_buf_t *dbp;
zfs_grow_blocksize(zp, len, tx);
VERIFY(0 == dmu_buf_hold(ZTOZSB(zp)->z_os,
zp->z_id, 0, FTAG, &dbp, DMU_READ_NO_PREFETCH));
dmu_buf_will_dirty(dbp, tx);
ASSERT3U(len, <=, dbp->db_size);
bcopy(link, dbp->db_data, len);
dmu_buf_rele(dbp, FTAG);
}
}
void
zfs_sa_get_scanstamp(znode_t *zp, xvattr_t *xvap)
{
zfs_sb_t *zsb = ZTOZSB(zp);
xoptattr_t *xoap;
ASSERT(MUTEX_HELD(&zp->z_lock));
VERIFY((xoap = xva_getxoptattr(xvap)) != NULL);
if (zp->z_is_sa) {
if (sa_lookup(zp->z_sa_hdl, SA_ZPL_SCANSTAMP(zsb),
&xoap->xoa_av_scanstamp,
sizeof (xoap->xoa_av_scanstamp)) != 0)
return;
} else {
dmu_object_info_t doi;
dmu_buf_t *db = sa_get_db(zp->z_sa_hdl);
int len;
if (!(zp->z_pflags & ZFS_BONUS_SCANSTAMP))
return;
sa_object_info(zp->z_sa_hdl, &doi);
len = sizeof (xoap->xoa_av_scanstamp) +
ZFS_OLD_ZNODE_PHYS_SIZE;
if (len <= doi.doi_bonus_size) {
(void) memcpy(xoap->xoa_av_scanstamp,
(caddr_t)db->db_data + ZFS_OLD_ZNODE_PHYS_SIZE,
sizeof (xoap->xoa_av_scanstamp));
}
}
XVA_SET_RTN(xvap, XAT_AV_SCANSTAMP);
}
void
zfs_sa_set_scanstamp(znode_t *zp, xvattr_t *xvap, dmu_tx_t *tx)
{
zfs_sb_t *zsb = ZTOZSB(zp);
xoptattr_t *xoap;
ASSERT(MUTEX_HELD(&zp->z_lock));
VERIFY((xoap = xva_getxoptattr(xvap)) != NULL);
if (zp->z_is_sa)
VERIFY(0 == sa_update(zp->z_sa_hdl, SA_ZPL_SCANSTAMP(zsb),
&xoap->xoa_av_scanstamp,
sizeof (xoap->xoa_av_scanstamp), tx));
else {
dmu_object_info_t doi;
dmu_buf_t *db = sa_get_db(zp->z_sa_hdl);
int len;
sa_object_info(zp->z_sa_hdl, &doi);
len = sizeof (xoap->xoa_av_scanstamp) +
ZFS_OLD_ZNODE_PHYS_SIZE;
if (len > doi.doi_bonus_size)
VERIFY(dmu_set_bonus(db, len, tx) == 0);
(void) memcpy((caddr_t)db->db_data + ZFS_OLD_ZNODE_PHYS_SIZE,
xoap->xoa_av_scanstamp, sizeof (xoap->xoa_av_scanstamp));
zp->z_pflags |= ZFS_BONUS_SCANSTAMP;
VERIFY(0 == sa_update(zp->z_sa_hdl, SA_ZPL_FLAGS(zsb),
&zp->z_pflags, sizeof (uint64_t), tx));
}
}
int
zfs_sa_get_xattr(znode_t *zp)
{
zfs_sb_t *zsb = ZTOZSB(zp);
char *obj;
int size;
int error;
ASSERT(RW_LOCK_HELD(&zp->z_xattr_lock));
ASSERT(!zp->z_xattr_cached);
ASSERT(zp->z_is_sa);
error = sa_size(zp->z_sa_hdl, SA_ZPL_DXATTR(zsb), &size);
if (error) {
if (error == ENOENT)
return nvlist_alloc(&zp->z_xattr_cached,
NV_UNIQUE_NAME, KM_SLEEP);
else
return (error);
}
obj = zio_buf_alloc(size);
error = sa_lookup(zp->z_sa_hdl, SA_ZPL_DXATTR(zsb), obj, size);
if (error == 0)
error = nvlist_unpack(obj, size, &zp->z_xattr_cached, KM_SLEEP);
zio_buf_free(obj, size);
return (error);
}
int
zfs_sa_set_xattr(znode_t *zp)
{
zfs_sb_t *zsb = ZTOZSB(zp);
dmu_tx_t *tx;
char *obj;
size_t size;
int error;
ASSERT(RW_WRITE_HELD(&zp->z_xattr_lock));
ASSERT(zp->z_xattr_cached);
ASSERT(zp->z_is_sa);
error = nvlist_size(zp->z_xattr_cached, &size, NV_ENCODE_XDR);
if ((error == 0) && (size > SA_ATTR_MAX_LEN))
error = EFBIG;
if (error)
goto out;
obj = zio_buf_alloc(size);
error = nvlist_pack(zp->z_xattr_cached, &obj, &size,
NV_ENCODE_XDR, KM_SLEEP);
if (error)
goto out_free;
tx = dmu_tx_create(zsb->z_os);
dmu_tx_hold_sa_create(tx, size);
dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_TRUE);
error = dmu_tx_assign(tx, TXG_WAIT);
if (error) {
dmu_tx_abort(tx);
} else {
VERIFY0(sa_update(zp->z_sa_hdl, SA_ZPL_DXATTR(zsb),
obj, size, tx));
dmu_tx_commit(tx);
}
out_free:
zio_buf_free(obj, size);
out:
return (error);
}
/*
* I'm not convinced we should do any of this upgrade.
* since the SA code can read both old/new znode formats
* with probably little to no performance difference.
*
* All new files will be created with the new format.
*/
void
zfs_sa_upgrade(sa_handle_t *hdl, dmu_tx_t *tx)
{
dmu_buf_t *db = sa_get_db(hdl);
znode_t *zp = sa_get_userdata(hdl);
zfs_sb_t *zsb = ZTOZSB(zp);
int count = 0;
sa_bulk_attr_t *bulk, *sa_attrs;
zfs_acl_locator_cb_t locate = { 0 };
uint64_t uid, gid, mode, rdev, xattr, parent;
uint64_t crtime[2], mtime[2], ctime[2];
zfs_acl_phys_t znode_acl;
char scanstamp[AV_SCANSTAMP_SZ];
boolean_t drop_lock = B_FALSE;
/*
* No upgrade if ACL isn't cached
* since we won't know which locks are held
* and ready the ACL would require special "locked"
* interfaces that would be messy
*/
if (zp->z_acl_cached == NULL || S_ISLNK(ZTOI(zp)->i_mode))
return;
/*
* If the z_lock is held and we aren't the owner
* the just return since we don't want to deadlock
* trying to update the status of z_is_sa. This
* file can then be upgraded at a later time.
*
* Otherwise, we know we are doing the
* sa_update() that caused us to enter this function.
*/
if (mutex_owner(&zp->z_lock) != curthread) {
if (mutex_tryenter(&zp->z_lock) == 0)
return;
else
drop_lock = B_TRUE;
}
/* First do a bulk query of the attributes that aren't cached */
bulk = kmem_alloc(sizeof (sa_bulk_attr_t) * 20, KM_SLEEP);
SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MTIME(zsb), NULL, &mtime, 16);
SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zsb), NULL, &ctime, 16);
SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CRTIME(zsb), NULL, &crtime, 16);
SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MODE(zsb), NULL, &mode, 8);
SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_PARENT(zsb), NULL, &parent, 8);
SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_XATTR(zsb), NULL, &xattr, 8);
SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_RDEV(zsb), NULL, &rdev, 8);
SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_UID(zsb), NULL, &uid, 8);
SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_GID(zsb), NULL, &gid, 8);
SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_ZNODE_ACL(zsb), NULL,
&znode_acl, 88);
if (sa_bulk_lookup_locked(hdl, bulk, count) != 0) {
kmem_free(bulk, sizeof (sa_bulk_attr_t) * 20);
goto done;
}
/*
* While the order here doesn't matter its best to try and organize
* it is such a way to pick up an already existing layout number
*/
count = 0;
sa_attrs = kmem_zalloc(sizeof (sa_bulk_attr_t) * 20, KM_SLEEP);
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_MODE(zsb), NULL, &mode, 8);
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_SIZE(zsb), NULL,
&zp->z_size, 8);
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_GEN(zsb),
NULL, &zp->z_gen, 8);
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_UID(zsb), NULL, &uid, 8);
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_GID(zsb), NULL, &gid, 8);
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_PARENT(zsb),
NULL, &parent, 8);
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_FLAGS(zsb), NULL,
&zp->z_pflags, 8);
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_ATIME(zsb), NULL,
zp->z_atime, 16);
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_MTIME(zsb), NULL,
&mtime, 16);
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_CTIME(zsb), NULL,
&ctime, 16);
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_CRTIME(zsb), NULL,
&crtime, 16);
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_LINKS(zsb), NULL,
&zp->z_links, 8);
if (S_ISBLK(ZTOI(zp)->i_mode) || S_ISCHR(ZTOI(zp)->i_mode))
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_RDEV(zsb), NULL,
&rdev, 8);
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_DACL_COUNT(zsb), NULL,
&zp->z_acl_cached->z_acl_count, 8);
if (zp->z_acl_cached->z_version < ZFS_ACL_VERSION_FUID)
zfs_acl_xform(zp, zp->z_acl_cached, CRED());
locate.cb_aclp = zp->z_acl_cached;
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_DACL_ACES(zsb),
zfs_acl_data_locator, &locate, zp->z_acl_cached->z_acl_bytes);
if (xattr)
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_XATTR(zsb),
NULL, &xattr, 8);
/* if scanstamp then add scanstamp */
if (zp->z_pflags & ZFS_BONUS_SCANSTAMP) {
bcopy((caddr_t)db->db_data + ZFS_OLD_ZNODE_PHYS_SIZE,
scanstamp, AV_SCANSTAMP_SZ);
SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_SCANSTAMP(zsb),
NULL, scanstamp, AV_SCANSTAMP_SZ);
zp->z_pflags &= ~ZFS_BONUS_SCANSTAMP;
}
VERIFY(dmu_set_bonustype(db, DMU_OT_SA, tx) == 0);
VERIFY(sa_replace_all_by_template_locked(hdl, sa_attrs,
count, tx) == 0);
if (znode_acl.z_acl_extern_obj)
VERIFY(0 == dmu_object_free(zsb->z_os,
znode_acl.z_acl_extern_obj, tx));
zp->z_is_sa = B_TRUE;
kmem_free(sa_attrs, sizeof (sa_bulk_attr_t) * 20);
kmem_free(bulk, sizeof (sa_bulk_attr_t) * 20);
done:
if (drop_lock)
mutex_exit(&zp->z_lock);
}
void
zfs_sa_upgrade_txholds(dmu_tx_t *tx, znode_t *zp)
{
if (!ZTOZSB(zp)->z_use_sa || zp->z_is_sa)
return;
dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_TRUE);
if (zfs_external_acl(zp)) {
dmu_tx_hold_free(tx, zfs_external_acl(zp), 0,
DMU_OBJECT_END);
}
}
EXPORT_SYMBOL(zfs_attr_table);
EXPORT_SYMBOL(zfs_sa_readlink);
EXPORT_SYMBOL(zfs_sa_symlink);
EXPORT_SYMBOL(zfs_sa_get_scanstamp);
EXPORT_SYMBOL(zfs_sa_set_scanstamp);
EXPORT_SYMBOL(zfs_sa_get_xattr);
EXPORT_SYMBOL(zfs_sa_set_xattr);
EXPORT_SYMBOL(zfs_sa_upgrade);
EXPORT_SYMBOL(zfs_sa_upgrade_txholds);
#endif
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