xattr: Add __vfs_{get,set,remove}xattr helpers

Right now, various places in the kernel check for the existence of
getxattr, setxattr, and removexattr inode operations and directly call
those operations.  Switch to helper functions and test for the IOP_XATTR
flag instead.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

6 files changed, 39 insertions, 49 deletions

diff --git a/security/commoncap.c b/security/commoncap.c
index 14540bd..8df676f 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -310,13 +310,8 @@ int cap_inode_need_killpriv(struct dentry *dentry)
 	struct inode *inode = d_backing_inode(dentry);
 	int error;
 
-	if (!inode->i_op->getxattr)
-	       return 0;
-
-	error = inode->i_op->getxattr(dentry, inode, XATTR_NAME_CAPS, NULL, 0);
-	if (error <= 0)
-		return 0;
-	return 1;
+	error = __vfs_getxattr(dentry, inode, XATTR_NAME_CAPS, NULL, 0);
+	return error > 0;
 }
 
 /**
@@ -329,12 +324,12 @@ int cap_inode_need_killpriv(struct dentry *dentry)
  */
 int cap_inode_killpriv(struct dentry *dentry)
 {
-	struct inode *inode = d_backing_inode(dentry);
-
-	if (!inode->i_op->removexattr)
-	       return 0;
+	int error;
 
-	return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS);
+	error = __vfs_removexattr(dentry, XATTR_NAME_CAPS);
+	if (error == -EOPNOTSUPP)
+		error = 0;
+	return error;
 }
 
 /*
@@ -394,11 +389,11 @@ int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data
 
 	memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
 
-	if (!inode || !inode->i_op->getxattr)
+	if (!inode)
 		return -ENODATA;
 
-	size = inode->i_op->getxattr((struct dentry *)dentry, inode,
-				     XATTR_NAME_CAPS, &caps, XATTR_CAPS_SZ);
+	size = __vfs_getxattr((struct dentry *)dentry, inode,
+			      XATTR_NAME_CAPS, &caps, XATTR_CAPS_SZ);
 	if (size == -ENODATA || size == -EOPNOTSUPP)
 		/* no data, that's ok */
 		return -ENODATA;
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index 11c1d30..bf66391 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -182,8 +182,9 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
 	int error;
 	int size;
 
-	if (!inode->i_op->getxattr)
+	if (!(inode->i_opflags & IOP_XATTR))
 		return -EOPNOTSUPP;
+
 	desc = init_desc(type);
 	if (IS_ERR(desc))
 		return PTR_ERR(desc);
@@ -253,8 +254,8 @@ int evm_update_evmxattr(struct dentry *dentry, const char *xattr_name,
 		rc = __vfs_setxattr_noperm(dentry, XATTR_NAME_EVM,
 					   &xattr_data,
 					   sizeof(xattr_data), 0);
-	} else if (rc == -ENODATA && inode->i_op->removexattr) {
-		rc = inode->i_op->removexattr(dentry, XATTR_NAME_EVM);
+	} else if (rc == -ENODATA && (inode->i_opflags & IOP_XATTR)) {
+		rc = __vfs_removexattr(dentry, XATTR_NAME_EVM);
 	}
 	return rc;
 }
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index b9e2628..ba86155 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -78,11 +78,11 @@ static int evm_find_protected_xattrs(struct dentry *dentry)
 	int error;
 	int count = 0;
 
-	if (!inode->i_op->getxattr)
+	if (!(inode->i_opflags & IOP_XATTR))
 		return -EOPNOTSUPP;
 
 	for (xattr = evm_config_xattrnames; *xattr != NULL; xattr++) {
-		error = inode->i_op->getxattr(dentry, inode, *xattr, NULL, 0);
+		error = __vfs_getxattr(dentry, inode, *xattr, NULL, 0);
 		if (error < 0) {
 			if (error == -ENODATA)
 				continue;
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 4b9b4a4..0cc40af 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -165,13 +165,13 @@ enum hash_algo ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value,
 int ima_read_xattr(struct dentry *dentry,
 		   struct evm_ima_xattr_data **xattr_value)
 {
-	struct inode *inode = d_backing_inode(dentry);
-
-	if (!inode->i_op->getxattr)
-		return 0;
+	ssize_t ret;
 
-	return vfs_getxattr_alloc(dentry, XATTR_NAME_IMA, (char **)xattr_value,
-				  0, GFP_NOFS);
+	ret = vfs_getxattr_alloc(dentry, XATTR_NAME_IMA, (char **)xattr_value,
+				 0, GFP_NOFS);
+	if (ret == -EOPNOTSUPP)
+		ret = 0;
+	return ret;
 }
 
 /*
@@ -195,7 +195,7 @@ int ima_appraise_measurement(enum ima_hooks func,
 	enum integrity_status status = INTEGRITY_UNKNOWN;
 	int rc = xattr_len, hash_start = 0;
 
-	if (!inode->i_op->getxattr)
+	if (!(inode->i_opflags & IOP_XATTR))
 		return INTEGRITY_UNKNOWN;
 
 	if (rc <= 0) {
@@ -322,10 +322,10 @@ void ima_inode_post_setattr(struct dentry *dentry)
 {
 	struct inode *inode = d_backing_inode(dentry);
 	struct integrity_iint_cache *iint;
-	int must_appraise, rc;
+	int must_appraise;
 
 	if (!(ima_policy_flag & IMA_APPRAISE) || !S_ISREG(inode->i_mode)
-	    || !inode->i_op->removexattr)
+	    || !(inode->i_opflags & IOP_XATTR))
 		return;
 
 	must_appraise = ima_must_appraise(inode, MAY_ACCESS, POST_SETATTR);
@@ -338,8 +338,7 @@ void ima_inode_post_setattr(struct dentry *dentry)
 			iint->flags |= IMA_APPRAISE;
 	}
 	if (!must_appraise)
-		rc = inode->i_op->removexattr(dentry, XATTR_NAME_IMA);
-	return;
+		__vfs_removexattr(dentry, XATTR_NAME_IMA);
 }
 
 /*
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 13185a6..3db31ac 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -507,14 +507,14 @@ static int sb_finish_set_opts(struct super_block *sb)
 		   the root directory.  -ENODATA is ok, as this may be
 		   the first boot of the SELinux kernel before we have
 		   assigned xattr values to the filesystem. */
-		if (!root_inode->i_op->getxattr) {
+		if (!(root_inode->i_opflags & IOP_XATTR)) {
 			printk(KERN_WARNING "SELinux: (dev %s, type %s) has no "
 			       "xattr support\n", sb->s_id, sb->s_type->name);
 			rc = -EOPNOTSUPP;
 			goto out;
 		}
-		rc = root_inode->i_op->getxattr(root, root_inode,
-						XATTR_NAME_SELINUX, NULL, 0);
+
+		rc = __vfs_getxattr(root, root_inode, XATTR_NAME_SELINUX, NULL, 0);
 		if (rc < 0 && rc != -ENODATA) {
 			if (rc == -EOPNOTSUPP)
 				printk(KERN_WARNING "SELinux: (dev %s, type "
@@ -1410,11 +1410,10 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
 	case SECURITY_FS_USE_NATIVE:
 		break;
 	case SECURITY_FS_USE_XATTR:
-		if (!inode->i_op->getxattr) {
+		if (!(inode->i_opflags & IOP_XATTR)) {
 			isec->sid = sbsec->def_sid;
 			break;
 		}
-
 		/* Need a dentry, since the xattr API requires one.
 		   Life would be simpler if we could just pass the inode. */
 		if (opt_dentry) {
@@ -1445,14 +1444,12 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
 			goto out_unlock;
 		}
 		context[len] = '\0';
-		rc = inode->i_op->getxattr(dentry, inode, XATTR_NAME_SELINUX,
-					   context, len);
+		rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, context, len);
 		if (rc == -ERANGE) {
 			kfree(context);
 
 			/* Need a larger buffer.  Query for the right size. */
-			rc = inode->i_op->getxattr(dentry, inode, XATTR_NAME_SELINUX,
-						   NULL, 0);
+			rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, NULL, 0);
 			if (rc < 0) {
 				dput(dentry);
 				goto out_unlock;
@@ -1465,9 +1462,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
 				goto out_unlock;
 			}
 			context[len] = '\0';
-			rc = inode->i_op->getxattr(dentry, inode,
-						   XATTR_NAME_SELINUX,
-						   context, len);
+			rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, context, len);
 		}
 		dput(dentry);
 		if (rc < 0) {
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 87a9741..516b3f5 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -265,14 +265,14 @@ static struct smack_known *smk_fetch(const char *name, struct inode *ip,
 	char *buffer;
 	struct smack_known *skp = NULL;
 
-	if (ip->i_op->getxattr == NULL)
+	if (!(ip->i_opflags & IOP_XATTR))
 		return ERR_PTR(-EOPNOTSUPP);
 
 	buffer = kzalloc(SMK_LONGLABEL, GFP_KERNEL);
 	if (buffer == NULL)
 		return ERR_PTR(-ENOMEM);
 
-	rc = ip->i_op->getxattr(dp, ip, name, buffer, SMK_LONGLABEL);
+	rc = __vfs_getxattr(dp, ip, name, buffer, SMK_LONGLABEL);
 	if (rc < 0)
 		skp = ERR_PTR(rc);
 	else if (rc == 0)
@@ -3520,8 +3520,8 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
 		 * It would be curious if the label of the task
 		 * does not match that assigned.
 		 */
-		if (inode->i_op->getxattr == NULL)
-			break;
+		if (!(inode->i_opflags & IOP_XATTR))
+		        break;
 		/*
 		 * Get the dentry for xattr.
 		 */
@@ -3545,12 +3545,12 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
 			 */
 			if (isp->smk_flags & SMK_INODE_CHANGED) {
 				isp->smk_flags &= ~SMK_INODE_CHANGED;
-				rc = inode->i_op->setxattr(dp, inode,
+				rc = __vfs_setxattr(dp, inode,
 					XATTR_NAME_SMACKTRANSMUTE,
 					TRANS_TRUE, TRANS_TRUE_SIZE,
 					0);
 			} else {
-				rc = inode->i_op->getxattr(dp, inode,
+				rc = __vfs_getxattr(dp, inode,
 					XATTR_NAME_SMACKTRANSMUTE, trattr,
 					TRANS_TRUE_SIZE);
 				if (rc >= 0 && strncmp(trattr, TRANS_TRUE,