xfs: remove the kuid/kgid conversion wrappers

mainline inclusion
from mainline-v5.6-rc4
commit ba8adad5
category: bugfix
bugzilla: 185881
CVE: CVE-2021-4037

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ba8adad5d036733d240fa8a8f4d055f3d4490562

-------------------------------------------------

Remove the XFS wrappers for converting from and to the kuid/kgid types.
Mostly this means switching to VFS i_{u,g}id_{read,write} helpers, but
in a few spots the calls to the conversion functions is open coded.
To match the use of sb->s_user_ns in the helpers and other file systems,
sb->s_user_ns is also used in the quota code.  The ACL code already does
the conversion in a grotty layering violation in the VFS xattr code,
so it keeps using init_user_ns for the identity mapping.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

conflicts:
fs/xfs/libxfs/xfs_inode_buf.c
fs/xfs/xfs_inode_item.c
Signed-off-by: NGuo Xuenan <guoxuenan@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

fs/xfs/libxfs/xfs_inode_buf.c

@@ -224,8 +224,8 @@ xfs_inode_from_disk(
 	}
 
 	to->di_format = from->di_format;
-	inode->i_uid = xfs_uid_to_kuid(be32_to_cpu(from->di_uid));
-	inode->i_gid = xfs_gid_to_kgid(be32_to_cpu(from->di_gid));
+	i_uid_write(inode, be32_to_cpu(from->di_uid));
+	i_gid_write(inode, be32_to_cpu(from->di_gid));
 	to->di_flushiter = be16_to_cpu(from->di_flushiter);
 
 	/*
@@ -278,8 +278,8 @@ xfs_inode_to_disk(
 
 	to->di_version = from->di_version;
 	to->di_format = from->di_format;
-	to->di_uid = cpu_to_be32(xfs_kuid_to_uid(inode->i_uid));
-	to->di_gid = cpu_to_be32(xfs_kgid_to_gid(inode->i_gid));
+	to->di_uid = cpu_to_be32(i_uid_read(inode));
+	to->di_gid = cpu_to_be32(i_gid_read(inode));
 	to->di_projid_lo = cpu_to_be16(from->di_projid_lo);
 	to->di_projid_hi = cpu_to_be16(from->di_projid_hi);
 

fs/xfs/xfs_acl.c

@@ -59,10 +59,12 @@ xfs_acl_from_disk(
 
 		switch (acl_e->e_tag) {
 		case ACL_USER:
-			acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id));
+			acl_e->e_uid = make_kuid(&init_user_ns,
+						 be32_to_cpu(ace->ae_id));
 			break;
 		case ACL_GROUP:
-			acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id));
+			acl_e->e_gid = make_kgid(&init_user_ns,
+						 be32_to_cpu(ace->ae_id));
 			break;
 		case ACL_USER_OBJ:
 		case ACL_GROUP_OBJ:
@@ -95,10 +97,12 @@ xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
 		ace->ae_tag = cpu_to_be32(acl_e->e_tag);
 		switch (acl_e->e_tag) {
 		case ACL_USER:
-			ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid));
+			ace->ae_id = cpu_to_be32(
+					from_kuid(&init_user_ns, acl_e->e_uid));
 			break;
 		case ACL_GROUP:
-			ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid));
+			ace->ae_id = cpu_to_be32(
+					from_kgid(&init_user_ns, acl_e->e_gid));
 			break;
 		default:
 			ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);

fs/xfs/xfs_dquot.c

@@ -833,9 +833,9 @@ xfs_qm_id_for_quotatype(
 {
 	switch (type) {
 	case XFS_DQ_USER:
-		return xfs_kuid_to_uid(VFS_I(ip)->i_uid);
+		return i_uid_read(VFS_I(ip));
 	case XFS_DQ_GROUP:
-		return xfs_kgid_to_gid(VFS_I(ip)->i_gid);
+		return i_gid_read(VFS_I(ip));
 	case XFS_DQ_PROJ:
 		return xfs_get_projid(ip);
 	}

fs/xfs/xfs_inode_item.c

@@ -307,8 +307,8 @@ xfs_inode_to_log_dinode(
 
 	to->di_version = from->di_version;
 	to->di_format = from->di_format;
-	to->di_uid = xfs_kuid_to_uid(inode->i_uid);
-	to->di_gid = xfs_kgid_to_gid(inode->i_gid);
+	to->di_uid = i_uid_read(inode);
+	to->di_gid = i_gid_read(inode);
 	to->di_projid_lo = from->di_projid_lo;
 	to->di_projid_hi = from->di_projid_hi;
 

fs/xfs/xfs_itable.c

@@ -66,8 +66,8 @@ xfs_bulkstat_one_int(
 	buf->bs_projid_lo = dic->di_projid_lo;
 	buf->bs_projid_hi = dic->di_projid_hi;
 	buf->bs_ino = ino;
-	buf->bs_uid = xfs_kuid_to_uid(inode->i_uid);
-	buf->bs_gid = xfs_kgid_to_gid(inode->i_gid);
+	buf->bs_uid = i_uid_read(inode);
+	buf->bs_gid = i_gid_read(inode);
 	buf->bs_size = dic->di_size;
 
 	buf->bs_nlink = inode->i_nlink;

fs/xfs/xfs_linux.h

@@ -165,32 +165,6 @@ struct xstats {
 
 extern struct xstats xfsstats;
 
-/* Kernel uid/gid conversion. These are used to convert to/from the on disk
- * uid_t/gid_t types to the kuid_t/kgid_t types that the kernel uses internally.
- * The conversion here is type only, the value will remain the same since we
- * are converting to the init_user_ns. The uid is later mapped to a particular
- * user namespace value when crossing the kernel/user boundary.
- */
-static inline uint32_t xfs_kuid_to_uid(kuid_t uid)
-{
-	return from_kuid(&init_user_ns, uid);
-}
-
-static inline kuid_t xfs_uid_to_kuid(uint32_t uid)
-{
-	return make_kuid(&init_user_ns, uid);
-}
-
-static inline uint32_t xfs_kgid_to_gid(kgid_t gid)
-{
-	return from_kgid(&init_user_ns, gid);
-}
-
-static inline kgid_t xfs_gid_to_kgid(uint32_t gid)
-{
-	return make_kgid(&init_user_ns, gid);
-}
-
 static inline dev_t xfs_to_linux_dev_t(xfs_dev_t dev)
 {
 	return MKDEV(sysv_major(dev) & 0x1ff, sysv_minor(dev));

fs/xfs/xfs_qm.c

@@ -329,8 +329,7 @@ xfs_qm_dqattach_locked(
 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 
 	if (XFS_IS_UQUOTA_ON(mp) && !ip->i_udquot) {
-		error = xfs_qm_dqattach_one(ip,
-				xfs_kuid_to_uid(VFS_I(ip)->i_uid),
+		error = xfs_qm_dqattach_one(ip, i_uid_read(VFS_I(ip)),
 				XFS_DQ_USER, doalloc, &ip->i_udquot);
 		if (error)
 			goto done;
@@ -338,8 +337,7 @@ xfs_qm_dqattach_locked(
 	}
 
 	if (XFS_IS_GQUOTA_ON(mp) && !ip->i_gdquot) {
-		error = xfs_qm_dqattach_one(ip,
-				xfs_kgid_to_gid(VFS_I(ip)->i_gid),
+		error = xfs_qm_dqattach_one(ip, i_gid_read(VFS_I(ip)),
 				XFS_DQ_GROUP, doalloc, &ip->i_gdquot);
 		if (error)
 			goto done;
@@ -1646,6 +1644,7 @@ xfs_qm_vop_dqalloc(
 {
 	struct xfs_mount	*mp = ip->i_mount;
 	struct inode		*inode = VFS_I(ip);
+	struct user_namespace	*user_ns = inode->i_sb->s_user_ns;
 	struct xfs_dquot	*uq = NULL;
 	struct xfs_dquot	*gq = NULL;
 	struct xfs_dquot	*pq = NULL;
@@ -1685,7 +1684,7 @@ xfs_qm_vop_dqalloc(
 			 * holding ilock.
 			 */
 			xfs_iunlock(ip, lockflags);
-			error = xfs_qm_dqget(mp, xfs_kuid_to_uid(uid),
+			error = xfs_qm_dqget(mp, from_kuid(user_ns, uid),
 					XFS_DQ_USER, true, &uq);
 			if (error) {
 				ASSERT(error != -ENOENT);
@@ -1709,7 +1708,7 @@ xfs_qm_vop_dqalloc(
 	if ((flags & XFS_QMOPT_GQUOTA) && XFS_IS_GQUOTA_ON(mp)) {
 		if (!gid_eq(inode->i_gid, gid)) {
 			xfs_iunlock(ip, lockflags);
-			error = xfs_qm_dqget(mp, xfs_kgid_to_gid(gid),
+			error = xfs_qm_dqget(mp, from_kgid(user_ns, gid),
 					XFS_DQ_GROUP, true, &gq);
 			if (error) {
 				ASSERT(error != -ENOENT);
@@ -1835,8 +1834,7 @@ xfs_qm_vop_chown_reserve(
 			XFS_QMOPT_RES_RTBLKS : XFS_QMOPT_RES_REGBLKS;
 
 	if (XFS_IS_UQUOTA_ON(mp) && udqp &&
-	    xfs_kuid_to_uid(VFS_I(ip)->i_uid) !=
-			be32_to_cpu(udqp->q_core.d_id)) {
+	    i_uid_read(VFS_I(ip)) != be32_to_cpu(udqp->q_core.d_id)) {
 		udq_delblks = udqp;
 		/*
 		 * If there are delayed allocation blocks, then we have to
@@ -1849,8 +1847,7 @@ xfs_qm_vop_chown_reserve(
 		}
 	}
 	if (XFS_IS_GQUOTA_ON(ip->i_mount) && gdqp &&
-	    xfs_kgid_to_gid(VFS_I(ip)->i_gid) !=
-			be32_to_cpu(gdqp->q_core.d_id)) {
+	    i_gid_read(VFS_I(ip)) != be32_to_cpu(gdqp->q_core.d_id)) {
 		gdq_delblks = gdqp;
 		if (delblks) {
 			ASSERT(ip->i_gdquot);
@@ -1947,16 +1944,14 @@ xfs_qm_vop_create_dqattach(
 
 	if (udqp && XFS_IS_UQUOTA_ON(mp)) {
 		ASSERT(ip->i_udquot == NULL);
-		ASSERT(xfs_kuid_to_uid(VFS_I(ip)->i_uid) ==
-			be32_to_cpu(udqp->q_core.d_id));
+		ASSERT(i_uid_read(VFS_I(ip)) == be32_to_cpu(udqp->q_core.d_id));
 
 		ip->i_udquot = xfs_qm_dqhold(udqp);
 		xfs_trans_mod_dquot(tp, udqp, XFS_TRANS_DQ_ICOUNT, 1);
 	}
 	if (gdqp && XFS_IS_GQUOTA_ON(mp)) {
 		ASSERT(ip->i_gdquot == NULL);
-		ASSERT(xfs_kgid_to_gid(VFS_I(ip)->i_gid) ==
-			be32_to_cpu(gdqp->q_core.d_id));
+		ASSERT(i_gid_read(VFS_I(ip)) == be32_to_cpu(gdqp->q_core.d_id));
 
 		ip->i_gdquot = xfs_qm_dqhold(gdqp);
 		xfs_trans_mod_dquot(tp, gdqp, XFS_TRANS_DQ_ICOUNT, 1);