[PATCH 0/5] Some more xattr cleanups

[PATCH 0/5] Some more xattr cleanups

[Andreas Gruenbacher]

Al,

here are some more cleanups for the work.xattr branch.

Thanks,
Andreas

Andreas Gruenbacher (5):
  jffs2: Remove jffs2_{get,set,remove}xattr macros
  hfs: Switch to generic xattr handlers
  kernfs: Switch to generic xattr handlers
  sockfs: getxattr: Fail with -EOPNOTSUPP for invalid attribute names
  sockfs: Get rid of getxattr iop

 arch/ia64/kernel/perfmon.c   |   4 +-
 drivers/gpu/drm/drm_drv.c    |   1 +
 fs/aio.c                     |   2 +-
 fs/anon_inodes.c             |   2 +-
 fs/block_dev.c               |   2 +-
 fs/btrfs/tests/btrfs-tests.c |   2 +-
 fs/hfs/attr.c                |  82 +++++++++++++++--------
 fs/hfs/hfs_fs.h              |   6 +-
 fs/hfs/inode.c               |   7 +-
 fs/hfs/super.c               |   1 +
 fs/jffs2/dir.c               |   6 +-
 fs/jffs2/file.c              |   6 +-
 fs/jffs2/symlink.c           |   6 +-
 fs/jffs2/xattr.h             |   6 --
 fs/kernfs/dir.c              |   6 +-
 fs/kernfs/inode.c            | 150 ++++++++++++++++++++++++-------------------
 fs/kernfs/kernfs-internal.h  |   6 +-
 fs/kernfs/mount.c            |   1 +
 fs/kernfs/symlink.c          |   6 +-
 fs/libfs.c                   |   3 +-
 fs/nsfs.c                    |   2 +-
 fs/pipe.c                    |   2 +-
 include/linux/fs.h           |   1 +
 net/socket.c                 |  60 +++++++++--------
 24 files changed, 203 insertions(+), 167 deletions(-)

-- 
2.5.5

[PATCH 1/5] jffs2: Remove jffs2_{get,set,remove}xattr macros

[Andreas Gruenbacher]

When sb->s_xattr is NULL, the generic_{get,set,remove}xattr functions
produce the same result that setting the {get,set,remove}xattr inode
operations to NULL produces; there is no need for these macros.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/jffs2/dir.c     | 6 +++---
 fs/jffs2/file.c    | 6 +++---
 fs/jffs2/symlink.c | 6 +++---
 fs/jffs2/xattr.h   | 6 ------
 4 files changed, 9 insertions(+), 15 deletions(-)

diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c
index 7a9579e..9130c7a 100644
--- a/fs/jffs2/dir.c
+++ b/fs/jffs2/dir.c
@@ -61,10 +61,10 @@ const struct inode_operations jffs2_dir_inode_operations =
 	.get_acl =	jffs2_get_acl,
 	.set_acl =	jffs2_set_acl,
 	.setattr =	jffs2_setattr,
-	.setxattr =	jffs2_setxattr,
-	.getxattr =	jffs2_getxattr,
+	.setxattr =	generic_setxattr,
+	.getxattr =	generic_getxattr,
 	.listxattr =	jffs2_listxattr,
-	.removexattr =	jffs2_removexattr
+	.removexattr =	generic_removexattr
 };
 
 /***********************************************************************/
diff --git a/fs/jffs2/file.c b/fs/jffs2/file.c
index cad86ba..bf543cb 100644
--- a/fs/jffs2/file.c
+++ b/fs/jffs2/file.c
@@ -66,10 +66,10 @@ const struct inode_operations jffs2_file_inode_operations =
 	.get_acl =	jffs2_get_acl,
 	.set_acl =	jffs2_set_acl,
 	.setattr =	jffs2_setattr,
-	.setxattr =	jffs2_setxattr,
-	.getxattr =	jffs2_getxattr,
+	.setxattr =	generic_setxattr,
+	.getxattr =	generic_getxattr,
 	.listxattr =	jffs2_listxattr,
-	.removexattr =	jffs2_removexattr
+	.removexattr =	generic_removexattr
 };
 
 const struct address_space_operations jffs2_file_address_operations =
diff --git a/fs/jffs2/symlink.c b/fs/jffs2/symlink.c
index 2cabd64..afe2d75 100644
--- a/fs/jffs2/symlink.c
+++ b/fs/jffs2/symlink.c
@@ -16,8 +16,8 @@ const struct inode_operations jffs2_symlink_inode_operations =
 	.readlink =	generic_readlink,
 	.get_link =	simple_get_link,
 	.setattr =	jffs2_setattr,
-	.setxattr =	jffs2_setxattr,
-	.getxattr =	jffs2_getxattr,
+	.setxattr =	generic_setxattr,
+	.getxattr =	generic_getxattr,
 	.listxattr =	jffs2_listxattr,
-	.removexattr =	jffs2_removexattr
+	.removexattr =	generic_removexattr
 };
diff --git a/fs/jffs2/xattr.h b/fs/jffs2/xattr.h
index 467ff37..720007b 100644
--- a/fs/jffs2/xattr.h
+++ b/fs/jffs2/xattr.h
@@ -99,9 +99,6 @@ extern const struct xattr_handler jffs2_user_xattr_handler;
 extern const struct xattr_handler jffs2_trusted_xattr_handler;
 
 extern ssize_t jffs2_listxattr(struct dentry *, char *, size_t);
-#define jffs2_getxattr		generic_getxattr
-#define jffs2_setxattr		generic_setxattr
-#define jffs2_removexattr	generic_removexattr
 
 #else
 
@@ -116,9 +113,6 @@ extern ssize_t jffs2_listxattr(struct dentry *, char *, size_t);
 
 #define jffs2_xattr_handlers	NULL
 #define jffs2_listxattr		NULL
-#define jffs2_getxattr		NULL
-#define jffs2_setxattr		NULL
-#define jffs2_removexattr	NULL
 
 #endif /* CONFIG_JFFS2_FS_XATTR */
 
-- 
2.5.5

[PATCH 2/5] hfs: Switch to generic xattr handlers

[Andreas Gruenbacher]

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/hfs/attr.c   | 82 +++++++++++++++++++++++++++++++++++++++------------------
 fs/hfs/hfs_fs.h |  6 +----
 fs/hfs/inode.c  |  7 ++---
 fs/hfs/super.c  |  1 +
 4 files changed, 62 insertions(+), 34 deletions(-)

diff --git a/fs/hfs/attr.c b/fs/hfs/attr.c
index 064f92f..8adcf33 100644
--- a/fs/hfs/attr.c
+++ b/fs/hfs/attr.c
@@ -13,10 +13,14 @@
 #include "hfs_fs.h"
 #include "btree.h"
 
-int hfs_setxattr(struct dentry *dentry, const char *name,
-		 const void *value, size_t size, int flags)
+enum hfs_xattr_type {
+	HFS_TYPE,
+	HFS_CREATOR,
+};
+
+static int __hfs_setxattr(struct inode *inode, enum hfs_xattr_type type,
+			  const void *value, size_t size, int flags)
 {
-	struct inode *inode = d_inode(dentry);
 	struct hfs_find_data fd;
 	hfs_cat_rec rec;
 	struct hfs_cat_file *file;
@@ -36,18 +40,22 @@ int hfs_setxattr(struct dentry *dentry, const char *name,
 			sizeof(struct hfs_cat_file));
 	file = &rec.file;
 
-	if (!strcmp(name, "hfs.type")) {
+	switch(type) {
+	case HFS_TYPE:
 		if (size == 4)
 			memcpy(&file->UsrWds.fdType, value, 4);
 		else
 			res = -ERANGE;
-	} else if (!strcmp(name, "hfs.creator")) {
+		break;
+
+	case HFS_CREATOR:
 		if (size == 4)
 			memcpy(&file->UsrWds.fdCreator, value, 4);
 		else
 			res = -ERANGE;
-	} else
-		res = -EOPNOTSUPP;
+		break;
+	}
+
 	if (!res)
 		hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 				sizeof(struct hfs_cat_file));
@@ -56,8 +64,8 @@ out:
 	return res;
 }
 
-ssize_t hfs_getxattr(struct dentry *unused, struct inode *inode,
-		     const char *name, void *value, size_t size)
+static ssize_t __hfs_getxattr(struct inode *inode, enum hfs_xattr_type type,
+			      void *value, size_t size)
 {
 	struct hfs_find_data fd;
 	hfs_cat_rec rec;
@@ -80,41 +88,63 @@ ssize_t hfs_getxattr(struct dentry *unused, struct inode *inode,
 	}
 	file = &rec.file;
 
-	if (!strcmp(name, "hfs.type")) {
+	switch(type) {
+	case HFS_TYPE:
 		if (size >= 4) {
 			memcpy(value, &file->UsrWds.fdType, 4);
 			res = 4;
 		} else
 			res = size ? -ERANGE : 4;
-	} else if (!strcmp(name, "hfs.creator")) {
+		break;
+
+	case HFS_CREATOR:
 		if (size >= 4) {
 			memcpy(value, &file->UsrWds.fdCreator, 4);
 			res = 4;
 		} else
 			res = size ? -ERANGE : 4;
-	} else
-		res = -ENODATA;
+		break;
+	}
+
 out:
 	if (size)
 		hfs_find_exit(&fd);
 	return res;
 }
 
-#define HFS_ATTRLIST_SIZE (sizeof("hfs.creator")+sizeof("hfs.type"))
-
-ssize_t hfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
+static int hfs_xattr_get(const struct xattr_handler *handler,
+			 struct dentry *unused, struct inode *inode,
+			 const char *name, void *value, size_t size)
 {
-	struct inode *inode = d_inode(dentry);
+	return __hfs_getxattr(inode, handler->flags, value, size);
+}
 
-	if (!S_ISREG(inode->i_mode) || HFS_IS_RSRC(inode))
+static int hfs_xattr_set(const struct xattr_handler *handler,
+			 struct dentry *dentry, const char *name,
+			 const void *value, size_t size, int flags)
+{
+	if (!value)
 		return -EOPNOTSUPP;
 
-	if (!buffer || !size)
-		return HFS_ATTRLIST_SIZE;
-	if (size < HFS_ATTRLIST_SIZE)
-		return -ERANGE;
-	strcpy(buffer, "hfs.type");
-	strcpy(buffer + sizeof("hfs.type"), "hfs.creator");
-
-	return HFS_ATTRLIST_SIZE;
+	return __hfs_setxattr(d_inode(dentry), handler->flags, value, size, flags);
 }
+
+static const struct xattr_handler hfs_creator_handler = {
+	.name = "hfs.creator",
+	.flags = HFS_CREATOR,
+	.get = hfs_xattr_get,
+	.set = hfs_xattr_set,
+};
+
+static const struct xattr_handler hfs_type_handler = {
+	.name = "hfs.type",
+	.flags = HFS_TYPE,
+	.get = hfs_xattr_get,
+	.set = hfs_xattr_set,
+};
+
+const struct xattr_handler *hfs_xattr_handlers[] = {
+	&hfs_creator_handler,
+	&hfs_type_handler,
+	NULL
+};
diff --git a/fs/hfs/hfs_fs.h b/fs/hfs/hfs_fs.h
index 79daa09..771dcfe 100644
--- a/fs/hfs/hfs_fs.h
+++ b/fs/hfs/hfs_fs.h
@@ -211,11 +211,7 @@ extern void hfs_evict_inode(struct inode *);
 extern void hfs_delete_inode(struct inode *);
 
 /* attr.c */
-extern int hfs_setxattr(struct dentry *dentry, const char *name,
-			const void *value, size_t size, int flags);
-extern ssize_t hfs_getxattr(struct dentry *dentry, struct inode *inode,
-			    const char *name, void *value, size_t size);
-extern ssize_t hfs_listxattr(struct dentry *dentry, char *buffer, size_t size);
+extern const struct xattr_handler *hfs_xattr_handlers[];
 
 /* mdb.c */
 extern int hfs_mdb_get(struct super_block *);
diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
index 6686bf3..bb9549b 100644
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -15,6 +15,7 @@
 #include <linux/mpage.h>
 #include <linux/sched.h>
 #include <linux/uio.h>
+#include <linux/xattr.h>
 
 #include "hfs_fs.h"
 #include "btree.h"
@@ -686,7 +687,7 @@ static const struct file_operations hfs_file_operations = {
 static const struct inode_operations hfs_file_inode_operations = {
 	.lookup		= hfs_file_lookup,
 	.setattr	= hfs_inode_setattr,
-	.setxattr	= hfs_setxattr,
-	.getxattr	= hfs_getxattr,
-	.listxattr	= hfs_listxattr,
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= generic_listxattr,
 };
diff --git a/fs/hfs/super.c b/fs/hfs/super.c
index 1ca95c2..bf6304a 100644
--- a/fs/hfs/super.c
+++ b/fs/hfs/super.c
@@ -406,6 +406,7 @@ static int hfs_fill_super(struct super_block *sb, void *data, int silent)
 	}
 
 	sb->s_op = &hfs_super_operations;
+	sb->s_xattr = hfs_xattr_handlers;
 	sb->s_flags |= MS_NODIRATIME;
 	mutex_init(&sbi->bitmap_lock);
 
-- 
2.5.5

[PATCH 3/5] kernfs: Switch to generic xattr handlers

[Andreas Gruenbacher]

Unlike with most other filesystems, xattrs in kernfs are attached to the
dentries (dentry->d_fsdata).  Once security modules start calling get
xattr handlers with a NULL dentry (because of an unknown dentry), we'll
have to start check for that in kernfs_xattr_get.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/kernfs/dir.c             |   6 +-
 fs/kernfs/inode.c           | 150 ++++++++++++++++++++++++--------------------
 fs/kernfs/kernfs-internal.h |   6 +-
 fs/kernfs/mount.c           |   1 +
 fs/kernfs/symlink.c         |   6 +-
 5 files changed, 91 insertions(+), 78 deletions(-)

diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 03b688d..f67d896 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -1125,9 +1125,9 @@ const struct inode_operations kernfs_dir_iops = {
 	.permission	= kernfs_iop_permission,
 	.setattr	= kernfs_iop_setattr,
 	.getattr	= kernfs_iop_getattr,
-	.setxattr	= kernfs_iop_setxattr,
-	.removexattr	= kernfs_iop_removexattr,
-	.getxattr	= kernfs_iop_getxattr,
+	.setxattr	= generic_setxattr,
+	.removexattr	= generic_removexattr,
+	.getxattr	= generic_getxattr,
 	.listxattr	= kernfs_iop_listxattr,
 
 	.mkdir		= kernfs_iop_mkdir,
diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
index b524722..1dfb44a 100644
--- a/fs/kernfs/inode.c
+++ b/fs/kernfs/inode.c
@@ -28,9 +28,9 @@ static const struct inode_operations kernfs_iops = {
 	.permission	= kernfs_iop_permission,
 	.setattr	= kernfs_iop_setattr,
 	.getattr	= kernfs_iop_getattr,
-	.setxattr	= kernfs_iop_setxattr,
-	.removexattr	= kernfs_iop_removexattr,
-	.getxattr	= kernfs_iop_getxattr,
+	.setxattr	= generic_setxattr,
+	.removexattr	= generic_removexattr,
+	.getxattr	= generic_getxattr,
 	.listxattr	= kernfs_iop_listxattr,
 };
 
@@ -157,70 +157,6 @@ static int kernfs_node_setsecdata(struct kernfs_node *kn, void **secdata,
 	return 0;
 }
 
-int kernfs_iop_setxattr(struct dentry *dentry, const char *name,
-			const void *value, size_t size, int flags)
-{
-	struct kernfs_node *kn = dentry->d_fsdata;
-	struct kernfs_iattrs *attrs;
-	void *secdata;
-	int error;
-	u32 secdata_len = 0;
-
-	attrs = kernfs_iattrs(kn);
-	if (!attrs)
-		return -ENOMEM;
-
-	if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) {
-		const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
-		error = security_inode_setsecurity(d_inode(dentry), suffix,
-						value, size, flags);
-		if (error)
-			return error;
-		error = security_inode_getsecctx(d_inode(dentry),
-						&secdata, &secdata_len);
-		if (error)
-			return error;
-
-		mutex_lock(&kernfs_mutex);
-		error = kernfs_node_setsecdata(kn, &secdata, &secdata_len);
-		mutex_unlock(&kernfs_mutex);
-
-		if (secdata)
-			security_release_secctx(secdata, secdata_len);
-		return error;
-	} else if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
-		return simple_xattr_set(&attrs->xattrs, name, value, size,
-					flags);
-	}
-
-	return -EINVAL;
-}
-
-int kernfs_iop_removexattr(struct dentry *dentry, const char *name)
-{
-	struct kernfs_node *kn = dentry->d_fsdata;
-	struct kernfs_iattrs *attrs;
-
-	attrs = kernfs_iattrs(kn);
-	if (!attrs)
-		return -ENOMEM;
-
-	return simple_xattr_set(&attrs->xattrs, name, NULL, 0, XATTR_REPLACE);
-}
-
-ssize_t kernfs_iop_getxattr(struct dentry *unused, struct inode *inode,
-			    const char *name, void *buf, size_t size)
-{
-	struct kernfs_node *kn = inode->i_private;
-	struct kernfs_iattrs *attrs;
-
-	attrs = kernfs_iattrs(kn);
-	if (!attrs)
-		return -ENOMEM;
-
-	return simple_xattr_get(&attrs->xattrs, name, buf, size);
-}
-
 ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size)
 {
 	struct kernfs_node *kn = dentry->d_fsdata;
@@ -370,3 +306,83 @@ int kernfs_iop_permission(struct inode *inode, int mask)
 
 	return generic_permission(inode, mask);
 }
+
+static int kernfs_xattr_get(const struct xattr_handler *handler,
+			    struct dentry *dentry, struct inode *inode,
+			    const char *suffix, void *value, size_t size)
+{
+	const char *name = xattr_full_name(handler, suffix);
+	struct kernfs_node *kn;
+	struct kernfs_iattrs *attrs;
+
+	kn = dentry->d_fsdata;
+	attrs = kernfs_iattrs(kn);
+	if (!attrs)
+		return -ENOMEM;
+
+	return simple_xattr_get(&attrs->xattrs, name, value, size);
+}
+
+static int kernfs_xattr_set(const struct xattr_handler *handler,
+			    struct dentry *dentry, const char *suffix,
+			    const void *value, size_t size, int flags)
+{
+	const char *name = xattr_full_name(handler, suffix);
+	struct kernfs_node *kn = dentry->d_fsdata;
+	struct kernfs_iattrs *attrs;
+
+	attrs = kernfs_iattrs(kn);
+	if (!attrs)
+		return -ENOMEM;
+
+	return simple_xattr_set(&attrs->xattrs, name, value, size, flags);
+}
+
+const struct xattr_handler kernfs_trusted_xattr_handler = {
+	.prefix = XATTR_TRUSTED_PREFIX,
+	.get = kernfs_xattr_get,
+	.set = kernfs_xattr_set,
+};
+
+static int kernfs_security_xattr_set(const struct xattr_handler *handler,
+				     struct dentry *dentry, const char *suffix,
+				     const void *value, size_t size, int flags)
+{
+	struct kernfs_node *kn = dentry->d_fsdata;
+	struct inode *inode = d_inode(dentry);
+	struct kernfs_iattrs *attrs;
+	void *secdata;
+	u32 secdata_len = 0;
+	int error;
+
+	attrs = kernfs_iattrs(kn);
+	if (!attrs)
+		return -ENOMEM;
+
+	error = security_inode_setsecurity(inode, suffix, value, size, flags);
+	if (error)
+		return error;
+	error = security_inode_getsecctx(inode, &secdata, &secdata_len);
+	if (error)
+		return error;
+
+	mutex_lock(&kernfs_mutex);
+	error = kernfs_node_setsecdata(kn, &secdata, &secdata_len);
+	mutex_unlock(&kernfs_mutex);
+
+	if (secdata)
+		security_release_secctx(secdata, secdata_len);
+	return error;
+}
+
+const struct xattr_handler kernfs_security_xattr_handler = {
+	.prefix = XATTR_SECURITY_PREFIX,
+	.get = kernfs_xattr_get,
+	.set = kernfs_security_xattr_set,
+};
+
+const struct xattr_handler *kernfs_xattr_handlers[] = {
+	&kernfs_trusted_xattr_handler,
+	&kernfs_security_xattr_handler,
+	NULL
+};
diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h
index 45c9192..bfd551b 100644
--- a/fs/kernfs/kernfs-internal.h
+++ b/fs/kernfs/kernfs-internal.h
@@ -76,16 +76,12 @@ extern struct kmem_cache *kernfs_node_cache;
 /*
  * inode.c
  */
+extern const struct xattr_handler *kernfs_xattr_handlers[];
 void kernfs_evict_inode(struct inode *inode);
 int kernfs_iop_permission(struct inode *inode, int mask);
 int kernfs_iop_setattr(struct dentry *dentry, struct iattr *iattr);
 int kernfs_iop_getattr(struct vfsmount *mnt, struct dentry *dentry,
 		       struct kstat *stat);
-int kernfs_iop_setxattr(struct dentry *dentry, const char *name, const void *value,
-			size_t size, int flags);
-int kernfs_iop_removexattr(struct dentry *dentry, const char *name);
-ssize_t kernfs_iop_getxattr(struct dentry *dentry, struct inode *inode,
-			    const char *name, void *buf, size_t size);
 ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size);
 
 /*
diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c
index b67dbcc..5446c3b 100644
--- a/fs/kernfs/mount.c
+++ b/fs/kernfs/mount.c
@@ -142,6 +142,7 @@ static int kernfs_fill_super(struct super_block *sb, unsigned long magic)
 	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 	sb->s_magic = magic;
 	sb->s_op = &kernfs_sops;
+	sb->s_xattr = kernfs_xattr_handlers;
 	sb->s_time_gran = 1;
 
 	/* get root inode, initialize and unlock it */
diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c
index 117b8b3..549a14c7 100644
--- a/fs/kernfs/symlink.c
+++ b/fs/kernfs/symlink.c
@@ -134,9 +134,9 @@ static const char *kernfs_iop_get_link(struct dentry *dentry,
 }
 
 const struct inode_operations kernfs_symlink_iops = {
-	.setxattr	= kernfs_iop_setxattr,
-	.removexattr	= kernfs_iop_removexattr,
-	.getxattr	= kernfs_iop_getxattr,
+	.setxattr	= generic_setxattr,
+	.removexattr	= generic_removexattr,
+	.getxattr	= generic_getxattr,
 	.listxattr	= kernfs_iop_listxattr,
 	.readlink	= generic_readlink,
 	.get_link	= kernfs_iop_get_link,
-- 
2.5.5

Re: [PATCH 3/5] kernfs: Switch to generic xattr handlers

[Greg Kroah-Hartman]

On Fri, Apr 29, 2016 at 04:18:35PM +0200, Andreas Gruenbacher wrote:
> Unlike with most other filesystems, xattrs in kernfs are attached to the
> dentries (dentry->d_fsdata).  Once security modules start calling get
> xattr handlers with a NULL dentry (because of an unknown dentry), we'll
> have to start check for that in kernfs_xattr_get.
> 
> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Note, I'm not the only maintainer of kernfs...

Anyway:
	Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Re: [PATCH 3/5] kernfs: Switch to generic xattr handlers

[Al Viro]

On Sat, Apr 30, 2016 at 10:02:31AM -0700, Greg Kroah-Hartman wrote:
> On Fri, Apr 29, 2016 at 04:18:35PM +0200, Andreas Gruenbacher wrote:
> > Unlike with most other filesystems, xattrs in kernfs are attached to the
> > dentries (dentry->d_fsdata).  Once security modules start calling get
> > xattr handlers with a NULL dentry (because of an unknown dentry), we'll
> > have to start check for that in kernfs_xattr_get.
> > 
> > Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> 
> Note, I'm not the only maintainer of kernfs...
> 
> Anyway:
> 	Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Guys, kernfs uses ->d_fsdata to get to them, but note
static void kernfs_init_inode(struct kernfs_node *kn, struct inode *inode)
{
        kernfs_get(kn);
        inode->i_private = kn;
IOW, inode->i_private would work just as well - it points to the same thing.

Re: [PATCH 3/5] kernfs: Switch to generic xattr handlers

[Andreas Grünbacher]

2016-04-30 19:02 GMT+02:00 Greg Kroah-Hartman <gregkh@linuxfoundation.org>:
> On Fri, Apr 29, 2016 at 04:18:35PM +0200, Andreas Gruenbacher wrote:
>> Unlike with most other filesystems, xattrs in kernfs are attached to the
>> dentries (dentry->d_fsdata).  Once security modules start calling get
>> xattr handlers with a NULL dentry (because of an unknown dentry), we'll
>> have to start check for that in kernfs_xattr_get.
>>
>> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>
> Note, I'm not the only maintainer of kernfs...

Hmm, that isn't clear from the MAINTAINERS file:

DRIVER CORE, KOBJECTS, DEBUGFS, KERNFS AND SYSFS
M:      Greg Kroah-Hartman <gregkh@linuxfoundation.org>
T:      git git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git
S:      Supported
F:      Documentation/kobject.txt
F:      drivers/base/
F:      fs/debugfs/
F:      fs/kernfs/
F:      fs/sysfs/
F:      include/linux/debugfs.h
F:      include/linux/kobj*
F:      lib/kobj*

> Anyway:
>         Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Thanks,
Andreas

Re: [PATCH 3/5] kernfs: Switch to generic xattr handlers

[Greg Kroah-Hartman]

On Sun, May 01, 2016 at 12:45:53PM +0200, Andreas Gr�nbacher wrote:
> 2016-04-30 19:02 GMT+02:00 Greg Kroah-Hartman <gregkh@linuxfoundation.org>:
> > On Fri, Apr 29, 2016 at 04:18:35PM +0200, Andreas Gruenbacher wrote:
> >> Unlike with most other filesystems, xattrs in kernfs are attached to the
> >> dentries (dentry->d_fsdata).  Once security modules start calling get
> >> xattr handlers with a NULL dentry (because of an unknown dentry), we'll
> >> have to start check for that in kernfs_xattr_get.
> >>
> >> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
> >> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> >
> > Note, I'm not the only maintainer of kernfs...
> 
> Hmm, that isn't clear from the MAINTAINERS file:
> 
> DRIVER CORE, KOBJECTS, DEBUGFS, KERNFS AND SYSFS
> M:      Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> T:      git git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git
> S:      Supported
> F:      Documentation/kobject.txt
> F:      drivers/base/
> F:      fs/debugfs/
> F:      fs/kernfs/
> F:      fs/sysfs/
> F:      include/linux/debugfs.h
> F:      include/linux/kobj*
> F:      lib/kobj*

Ah, sneaky Tejun, he didn't put his name on it, but if you use
get_maintainer.pl he should show up :)

thanks,

greg k-h

[PATCH 4/5] sockfs: getxattr: Fail with -EOPNOTSUPP for invalid attribute names

[Andreas Gruenbacher]

The standard return value for unsupported attribute names is
-EOPNOTSUPP, as opposed to undefined but supported attributes
(-ENODATA).  Also, fail for attribute names like
"system.sockprotonameXXX" and simplify the code a bit.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 net/socket.c | 24 ++++++------------------
 1 file changed, 6 insertions(+), 18 deletions(-)

diff --git a/net/socket.c b/net/socket.c
index 35e4523..23fdd83 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -469,27 +469,15 @@ static struct socket *sockfd_lookup_light(int fd, int *err, int *fput_needed)
 static ssize_t sockfs_getxattr(struct dentry *dentry, struct inode *inode,
 			       const char *name, void *value, size_t size)
 {
-	const char *proto_name;
-	size_t proto_size;
-	int error;
-
-	error = -ENODATA;
-	if (!strncmp(name, XATTR_NAME_SOCKPROTONAME, XATTR_NAME_SOCKPROTONAME_LEN)) {
-		proto_name = dentry->d_name.name;
-		proto_size = strlen(proto_name);
-
+	if (!strcmp(name, XATTR_NAME_SOCKPROTONAME)) {
 		if (value) {
-			error = -ERANGE;
-			if (proto_size + 1 > size)
-				goto out;
-
-			strncpy(value, proto_name, proto_size + 1);
+			if (dentry->d_name.len + 1 > size)
+				return -ERANGE;
+			memcpy(value, dentry->d_name.name, dentry->d_name.len + 1);
 		}
-		error = proto_size + 1;
+		return dentry->d_name.len + 1;
 	}
-
-out:
-	return error;
+	return -EOPNOTSUPP;
 }
 
 static ssize_t sockfs_listxattr(struct dentry *dentry, char *buffer,
-- 
2.5.5

[PATCH 5/5] sockfs: Get rid of getxattr iop

[Andreas Gruenbacher]

If we allow pseudo-filesystems created with mount_pseudo to have xattr
handlers, we can replace sockfs_getxattr with a sockfs_xattr_get handler
to use the xattr handler name parsing.  In this case, the improvement is
only a small one, though.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 arch/ia64/kernel/perfmon.c   |  4 ++--
 drivers/gpu/drm/drm_drv.c    |  1 +
 fs/aio.c                     |  2 +-
 fs/anon_inodes.c             |  2 +-
 fs/block_dev.c               |  2 +-
 fs/btrfs/tests/btrfs-tests.c |  2 +-
 fs/libfs.c                   |  3 ++-
 fs/nsfs.c                    |  2 +-
 fs/pipe.c                    |  2 +-
 include/linux/fs.h           |  1 +
 net/socket.c                 | 48 ++++++++++++++++++++++++++------------------
 11 files changed, 41 insertions(+), 28 deletions(-)

diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index 9cd607b..782cddb 100644
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -611,8 +611,8 @@ static const struct dentry_operations pfmfs_dentry_operations;
 static struct dentry *
 pfmfs_mount(struct file_system_type *fs_type, int flags, const char *dev_name, void *data)
 {
-	return mount_pseudo(fs_type, "pfm:", NULL, &pfmfs_dentry_operations,
-			PFMFS_MAGIC);
+	return mount_pseudo(fs_type, "pfm:", NULL, NULL,
+			    &pfmfs_dentry_operations, PFMFS_MAGIC);
 }
 
 static struct file_system_type pfm_fs_type = {
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 167c8d3..3512bb8 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -509,6 +509,7 @@ static struct dentry *drm_fs_mount(struct file_system_type *fs_type, int flags,
 	return mount_pseudo(fs_type,
 			    "drm:",
 			    &drm_fs_sops,
+			    NULL,
 			    &drm_fs_dops,
 			    0x010203ff);
 }
diff --git a/fs/aio.c b/fs/aio.c
index 155f842..6f1387f 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -239,7 +239,7 @@ static struct dentry *aio_mount(struct file_system_type *fs_type,
 	static const struct dentry_operations ops = {
 		.d_dname	= simple_dname,
 	};
-	return mount_pseudo(fs_type, "aio:", NULL, &ops, AIO_RING_MAGIC);
+	return mount_pseudo(fs_type, "aio:", NULL, NULL, &ops, AIO_RING_MAGIC);
 }
 
 /* aio_setup
diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c
index 80ef38c..5e1aeea1 100644
--- a/fs/anon_inodes.c
+++ b/fs/anon_inodes.c
@@ -41,7 +41,7 @@ static const struct dentry_operations anon_inodefs_dentry_operations = {
 static struct dentry *anon_inodefs_mount(struct file_system_type *fs_type,
 				int flags, const char *dev_name, void *data)
 {
-	return mount_pseudo(fs_type, "anon_inode:", NULL,
+	return mount_pseudo(fs_type, "anon_inode:", NULL, NULL,
 			&anon_inodefs_dentry_operations, ANON_INODE_FS_MAGIC);
 }
 
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 3172c4e..8c605ff 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -576,7 +576,7 @@ static struct dentry *bd_mount(struct file_system_type *fs_type,
 	int flags, const char *dev_name, void *data)
 {
 	struct dentry *dent;
-	dent = mount_pseudo(fs_type, "bdev:", &bdev_sops, NULL, BDEVFS_MAGIC);
+	dent = mount_pseudo(fs_type, "bdev:", &bdev_sops, NULL, NULL, BDEVFS_MAGIC);
 	if (dent)
 		dent->d_sb->s_iflags |= SB_I_CGROUPWB;
 	return dent;
diff --git a/fs/btrfs/tests/btrfs-tests.c b/fs/btrfs/tests/btrfs-tests.c
index f54bf45..ebecf33 100644
--- a/fs/btrfs/tests/btrfs-tests.c
+++ b/fs/btrfs/tests/btrfs-tests.c
@@ -40,7 +40,7 @@ static struct dentry *btrfs_test_mount(struct file_system_type *fs_type,
 				       void *data)
 {
 	return mount_pseudo(fs_type, "btrfs_test:", &btrfs_test_super_ops,
-			    NULL, BTRFS_TEST_MAGIC);
+			    NULL, NULL, BTRFS_TEST_MAGIC);
 }
 
 static struct file_system_type test_type = {
diff --git a/fs/libfs.c b/fs/libfs.c
index 03332f4..2a820bb 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -209,7 +209,7 @@ static const struct super_operations simple_super_operations = {
  * will never be mountable)
  */
 struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name,
-	const struct super_operations *ops,
+	const struct super_operations *ops, const struct xattr_handler **xattr,
 	const struct dentry_operations *dops, unsigned long magic)
 {
 	struct super_block *s;
@@ -226,6 +226,7 @@ struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name,
 	s->s_blocksize_bits = PAGE_SHIFT;
 	s->s_magic = magic;
 	s->s_op = ops ? ops : &simple_super_operations;
+	s->s_xattr = xattr;
 	s->s_time_gran = 1;
 	root = new_inode(s);
 	if (!root)
diff --git a/fs/nsfs.c b/fs/nsfs.c
index 8f20d60..e151cc3 100644
--- a/fs/nsfs.c
+++ b/fs/nsfs.c
@@ -154,7 +154,7 @@ static const struct super_operations nsfs_ops = {
 static struct dentry *nsfs_mount(struct file_system_type *fs_type,
 			int flags, const char *dev_name, void *data)
 {
-	return mount_pseudo(fs_type, "nsfs:", &nsfs_ops,
+	return mount_pseudo(fs_type, "nsfs:", &nsfs_ops, NULL,
 			&ns_dentry_operations, NSFS_MAGIC);
 }
 static struct file_system_type nsfs = {
diff --git a/fs/pipe.c b/fs/pipe.c
index ab8dad3..60a9180 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -1143,7 +1143,7 @@ static const struct super_operations pipefs_ops = {
 static struct dentry *pipefs_mount(struct file_system_type *fs_type,
 			 int flags, const char *dev_name, void *data)
 {
-	return mount_pseudo(fs_type, "pipe:", &pipefs_ops,
+	return mount_pseudo(fs_type, "pipe:", &pipefs_ops, NULL,
 			&pipefs_dentry_operations, PIPEFS_MAGIC);
 }
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1b5fcae..3489609 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2030,6 +2030,7 @@ struct super_block *sget(struct file_system_type *type,
 			int flags, void *data);
 extern struct dentry *mount_pseudo(struct file_system_type *, char *,
 	const struct super_operations *ops,
+	const struct xattr_handler **xattr,
 	const struct dentry_operations *dops,
 	unsigned long);
 
diff --git a/net/socket.c b/net/socket.c
index 23fdd83..3ef77ab 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -320,11 +320,38 @@ static const struct dentry_operations sockfs_dentry_operations = {
 	.d_dname  = sockfs_dname,
 };
 
+static int sockfs_xattr_get(const struct xattr_handler *handler,
+			    struct dentry *dentry, struct inode *inode,
+			    const char *suffix, void *value, size_t size)
+{
+	if (value) {
+		if (dentry->d_name.len + 1 > size)
+			return -ERANGE;
+		memcpy(value, dentry->d_name.name, dentry->d_name.len + 1);
+	}
+	return dentry->d_name.len + 1;
+}
+
+#define XATTR_SOCKPROTONAME_SUFFIX "sockprotoname"
+#define XATTR_NAME_SOCKPROTONAME (XATTR_SYSTEM_PREFIX XATTR_SOCKPROTONAME_SUFFIX)
+#define XATTR_NAME_SOCKPROTONAME_LEN (sizeof(XATTR_NAME_SOCKPROTONAME)-1)
+
+static const struct xattr_handler sockfs_xattr_handler = {
+	.name = XATTR_NAME_SOCKPROTONAME,
+	.get = sockfs_xattr_get,
+};
+
+static const struct xattr_handler *sockfs_xattr_handlers[] = {
+	&sockfs_xattr_handler,
+	NULL
+};
+
 static struct dentry *sockfs_mount(struct file_system_type *fs_type,
 			 int flags, const char *dev_name, void *data)
 {
 	return mount_pseudo(fs_type, "socket:", &sockfs_ops,
-		&sockfs_dentry_operations, SOCKFS_MAGIC);
+			    sockfs_xattr_handlers,
+			    &sockfs_dentry_operations, SOCKFS_MAGIC);
 }
 
 static struct vfsmount *sock_mnt __read_mostly;
@@ -463,23 +490,6 @@ static struct socket *sockfd_lookup_light(int fd, int *err, int *fput_needed)
 	return NULL;
 }
 
-#define XATTR_SOCKPROTONAME_SUFFIX "sockprotoname"
-#define XATTR_NAME_SOCKPROTONAME (XATTR_SYSTEM_PREFIX XATTR_SOCKPROTONAME_SUFFIX)
-#define XATTR_NAME_SOCKPROTONAME_LEN (sizeof(XATTR_NAME_SOCKPROTONAME)-1)
-static ssize_t sockfs_getxattr(struct dentry *dentry, struct inode *inode,
-			       const char *name, void *value, size_t size)
-{
-	if (!strcmp(name, XATTR_NAME_SOCKPROTONAME)) {
-		if (value) {
-			if (dentry->d_name.len + 1 > size)
-				return -ERANGE;
-			memcpy(value, dentry->d_name.name, dentry->d_name.len + 1);
-		}
-		return dentry->d_name.len + 1;
-	}
-	return -EOPNOTSUPP;
-}
-
 static ssize_t sockfs_listxattr(struct dentry *dentry, char *buffer,
 				size_t size)
 {
@@ -509,7 +519,7 @@ static ssize_t sockfs_listxattr(struct dentry *dentry, char *buffer,
 }
 
 static const struct inode_operations sockfs_inode_ops = {
-	.getxattr = sockfs_getxattr,
+	.getxattr = generic_getxattr,
 	.listxattr = sockfs_listxattr,
 };
 
-- 
2.5.5