From 3767e255b390d72f9a33c08d9e86c5f21f25860f Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Fri, 27 May 2016 11:06:05 -0400
Subject: switch ->setxattr() to passing dentry and inode separately

smack ->d_instantiate() uses ->setxattr(), so to be able to call it before
we'd hashed the new dentry and attached it to inode, we need ->setxattr()
instances getting the inode as an explicit argument rather than obtaining
it from dentry.

Similar change for ->getxattr() had been done in commit ce23e64.  Unlike
->getxattr() (which is used by both selinux and smack instances of
->d_instantiate()) ->setxattr() is used only by smack one and unfortunately
it got missed back then.

Reported-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Tested-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 Documentation/filesystems/porting                    |  7 +++++++
 drivers/staging/lustre/lustre/llite/llite_internal.h |  4 ++--
 drivers/staging/lustre/lustre/llite/xattr.c          |  6 ++----
 fs/bad_inode.c                                       |  4 ++--
 fs/ecryptfs/crypto.c                                 |  9 +++++----
 fs/ecryptfs/ecryptfs_kernel.h                        |  4 ++--
 fs/ecryptfs/inode.c                                  |  7 ++++---
 fs/ecryptfs/mmap.c                                   |  3 ++-
 fs/fuse/dir.c                                        |  6 +++---
 fs/hfs/attr.c                                        |  6 +++---
 fs/hfs/hfs_fs.h                                      |  2 +-
 fs/kernfs/inode.c                                    | 11 ++++++-----
 fs/kernfs/kernfs-internal.h                          |  3 ++-
 fs/libfs.c                                           |  5 +++--
 fs/overlayfs/inode.c                                 |  5 +++--
 fs/overlayfs/overlayfs.h                             |  5 +++--
 fs/xattr.c                                           |  8 ++++----
 include/linux/fs.h                                   |  3 ++-
 include/linux/xattr.h                                |  3 ++-
 security/smack/smack_lsm.c                           |  2 +-
 20 files changed, 59 insertions(+), 44 deletions(-)

diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index 46f3bb7a02f5..a5fb89cac615 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -578,3 +578,10 @@ in your dentry operations instead.
 --
 [mandatory]
 	->atomic_open() calls without O_CREAT may happen in parallel.
+--
+[mandatory]
+	->setxattr() and xattr_handler.set() get dentry and inode passed separately.
+	dentry might be yet to be attached to inode, so do _not_ use its ->d_inode
+	in the instances.  Rationale: !@#!@# security_d_instantiate() needs to be
+	called before we attach dentry to inode and !@#!@##!@$!$#!@#$!@$!@$ smack
+	->d_instantiate() uses not just ->getxattr() but ->setxattr() as well.
diff --git a/drivers/staging/lustre/lustre/llite/llite_internal.h b/drivers/staging/lustre/lustre/llite/llite_internal.h
index ce1f949430f1..3f2f30b6542c 100644
--- a/drivers/staging/lustre/lustre/llite/llite_internal.h
+++ b/drivers/staging/lustre/lustre/llite/llite_internal.h
@@ -976,8 +976,8 @@ static inline __u64 ll_file_maxbytes(struct inode *inode)
 }
 
 /* llite/xattr.c */
-int ll_setxattr(struct dentry *dentry, const char *name,
-		const void *value, size_t size, int flags);
+int ll_setxattr(struct dentry *dentry, struct inode *inode,
+		const char *name, const void *value, size_t size, int flags);
 ssize_t ll_getxattr(struct dentry *dentry, struct inode *inode,
 		    const char *name, void *buffer, size_t size);
 ssize_t ll_listxattr(struct dentry *dentry, char *buffer, size_t size);
diff --git a/drivers/staging/lustre/lustre/llite/xattr.c b/drivers/staging/lustre/lustre/llite/xattr.c
index ed4de04381c3..608014b0dbcd 100644
--- a/drivers/staging/lustre/lustre/llite/xattr.c
+++ b/drivers/staging/lustre/lustre/llite/xattr.c
@@ -211,11 +211,9 @@ int ll_setxattr_common(struct inode *inode, const char *name,
 	return 0;
 }
 
-int ll_setxattr(struct dentry *dentry, const char *name,
-		const void *value, size_t size, int flags)
+int ll_setxattr(struct dentry *dentry, struct inode *inode,
+		const char *name, const void *value, size_t size, int flags)
 {
-	struct inode *inode = d_inode(dentry);
-
 	LASSERT(inode);
 	LASSERT(name);
 
diff --git a/fs/bad_inode.c b/fs/bad_inode.c
index 72e35b721608..3ba385eaa26e 100644
--- a/fs/bad_inode.c
+++ b/fs/bad_inode.c
@@ -100,8 +100,8 @@ static int bad_inode_setattr(struct dentry *direntry, struct iattr *attrs)
 	return -EIO;
 }
 
-static int bad_inode_setxattr(struct dentry *dentry, const char *name,
-		const void *value, size_t size, int flags)
+static int bad_inode_setxattr(struct dentry *dentry, struct inode *inode,
+		const char *name, const void *value, size_t size, int flags)
 {
 	return -EIO;
 }
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index ebd40f46ed4c..0d8eb3455b34 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1141,12 +1141,13 @@ ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode,
 
 static int
 ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
+				 struct inode *ecryptfs_inode,
 				 char *page_virt, size_t size)
 {
 	int rc;
 
-	rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
-			       size, 0);
+	rc = ecryptfs_setxattr(ecryptfs_dentry, ecryptfs_inode,
+			       ECRYPTFS_XATTR_NAME, page_virt, size, 0);
 	return rc;
 }
 
@@ -1215,8 +1216,8 @@ int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
 		goto out_free;
 	}
 	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
-		rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
-						      size);
+		rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, ecryptfs_inode,
+						      virt, size);
 	else
 		rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt,
 							 virt_len);
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 3ec495db7e82..4ba1547bb9ad 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -609,8 +609,8 @@ ssize_t
 ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
 			const char *name, void *value, size_t size);
 int
-ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
-		  size_t size, int flags);
+ecryptfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name,
+		  const void *value, size_t size, int flags);
 int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode);
 #ifdef CONFIG_ECRYPT_FS_MESSAGING
 int ecryptfs_process_response(struct ecryptfs_daemon *daemon,
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 318b04689d76..9d153b6a1d72 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -1001,7 +1001,8 @@ static int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 }
 
 int
-ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
+ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
+		  const char *name, const void *value,
 		  size_t size, int flags)
 {
 	int rc = 0;
@@ -1014,8 +1015,8 @@ ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 	}
 
 	rc = vfs_setxattr(lower_dentry, name, value, size, flags);
-	if (!rc && d_really_is_positive(dentry))
-		fsstack_copy_attr_all(d_inode(dentry), d_inode(lower_dentry));
+	if (!rc && inode)
+		fsstack_copy_attr_all(inode, d_inode(lower_dentry));
 out:
 	return rc;
 }
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index 148d11b514fb..9c3437c8a5b1 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -442,7 +442,8 @@ static int ecryptfs_write_inode_size_to_xattr(struct inode *ecryptfs_inode)
 	if (size < 0)
 		size = 8;
 	put_unaligned_be64(i_size_read(ecryptfs_inode), xattr_virt);
-	rc = lower_inode->i_op->setxattr(lower_dentry, ECRYPTFS_XATTR_NAME,
+	rc = lower_inode->i_op->setxattr(lower_dentry, lower_inode,
+					 ECRYPTFS_XATTR_NAME,
 					 xattr_virt, size, 0);
 	inode_unlock(lower_inode);
 	if (rc)
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index b9419058108f..ccd4971cc6c1 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1719,10 +1719,10 @@ static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry,
 	return fuse_update_attributes(inode, stat, NULL, NULL);
 }
 
-static int fuse_setxattr(struct dentry *entry, const char *name,
-			 const void *value, size_t size, int flags)
+static int fuse_setxattr(struct dentry *unused, struct inode *inode,
+			 const char *name, const void *value,
+			 size_t size, int flags)
 {
-	struct inode *inode = d_inode(entry);
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	FUSE_ARGS(args);
 	struct fuse_setxattr_in inarg;
diff --git a/fs/hfs/attr.c b/fs/hfs/attr.c
index 064f92f17efc..d9a86919fdf6 100644
--- a/fs/hfs/attr.c
+++ b/fs/hfs/attr.c
@@ -13,10 +13,10 @@
 #include "hfs_fs.h"
 #include "btree.h"
 
-int hfs_setxattr(struct dentry *dentry, const char *name,
-		 const void *value, size_t size, int flags)
+int hfs_setxattr(struct dentry *unused, struct inode *inode,
+		 const char *name, 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;
diff --git a/fs/hfs/hfs_fs.h b/fs/hfs/hfs_fs.h
index fa3eed86837c..ee2f385811c8 100644
--- a/fs/hfs/hfs_fs.h
+++ b/fs/hfs/hfs_fs.h
@@ -212,7 +212,7 @@ 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,
+extern int hfs_setxattr(struct dentry *dentry, struct inode *inode, 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);
diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
index 1719649d7ad7..63b925d5ba1e 100644
--- a/fs/kernfs/inode.c
+++ b/fs/kernfs/inode.c
@@ -160,10 +160,11 @@ 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)
+int kernfs_iop_setxattr(struct dentry *unused, struct inode *inode,
+			const char *name, const void *value,
+			size_t size, int flags)
 {
-	struct kernfs_node *kn = dentry->d_fsdata;
+	struct kernfs_node *kn = inode->i_private;
 	struct kernfs_iattrs *attrs;
 	void *secdata;
 	int error;
@@ -175,11 +176,11 @@ int kernfs_iop_setxattr(struct dentry *dentry, const char *name,
 
 	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,
+		error = security_inode_setsecurity(inode, suffix,
 						value, size, flags);
 		if (error)
 			return error;
-		error = security_inode_getsecctx(d_inode(dentry),
+		error = security_inode_getsecctx(inode,
 						&secdata, &secdata_len);
 		if (error)
 			return error;
diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h
index 45c9192c276e..37159235ac10 100644
--- a/fs/kernfs/kernfs-internal.h
+++ b/fs/kernfs/kernfs-internal.h
@@ -81,7 +81,8 @@ 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,
+int kernfs_iop_setxattr(struct dentry *dentry, struct inode *inode,
+			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,
diff --git a/fs/libfs.c b/fs/libfs.c
index 8765ff1adc07..3db2721144c2 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -1118,8 +1118,9 @@ static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr)
 	return -EPERM;
 }
 
-static int empty_dir_setxattr(struct dentry *dentry, const char *name,
-			      const void *value, size_t size, int flags)
+static int empty_dir_setxattr(struct dentry *dentry, struct inode *inode,
+			      const char *name, const void *value,
+			      size_t size, int flags)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index c7b31a03dc9c..0ed7c4012437 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -210,8 +210,9 @@ static bool ovl_is_private_xattr(const char *name)
 	return strncmp(name, OVL_XATTR_PRE_NAME, OVL_XATTR_PRE_LEN) == 0;
 }
 
-int ovl_setxattr(struct dentry *dentry, const char *name,
-		 const void *value, size_t size, int flags)
+int ovl_setxattr(struct dentry *dentry, struct inode *inode,
+		 const char *name, const void *value,
+		 size_t size, int flags)
 {
 	int err;
 	struct dentry *upperdentry;
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 99ec4b035237..d79577eb3937 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -171,8 +171,9 @@ int ovl_check_d_type_supported(struct path *realpath);
 /* inode.c */
 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
 int ovl_permission(struct inode *inode, int mask);
-int ovl_setxattr(struct dentry *dentry, const char *name,
-		 const void *value, size_t size, int flags);
+int ovl_setxattr(struct dentry *dentry, struct inode *inode,
+		 const char *name, const void *value,
+		 size_t size, int flags);
 ssize_t ovl_getxattr(struct dentry *dentry, struct inode *inode,
 		     const char *name, void *value, size_t size);
 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
diff --git a/fs/xattr.c b/fs/xattr.c
index b16d07889700..4beafc43daa5 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -100,7 +100,7 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
 	if (issec)
 		inode->i_flags &= ~S_NOSEC;
 	if (inode->i_op->setxattr) {
-		error = inode->i_op->setxattr(dentry, name, value, size, flags);
+		error = inode->i_op->setxattr(dentry, inode, name, value, size, flags);
 		if (!error) {
 			fsnotify_xattr(dentry);
 			security_inode_post_setxattr(dentry, name, value,
@@ -745,7 +745,8 @@ generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
  * Find the handler for the prefix and dispatch its set() operation.
  */
 int
-generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags)
+generic_setxattr(struct dentry *dentry, struct inode *inode, const char *name,
+		 const void *value, size_t size, int flags)
 {
 	const struct xattr_handler *handler;
 
@@ -754,8 +755,7 @@ generic_setxattr(struct dentry *dentry, const char *name, const void *value, siz
 	handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
 	if (IS_ERR(handler))
 		return PTR_ERR(handler);
-	return handler->set(handler, dentry, d_inode(dentry), name, value,
-			    size, flags);
+	return handler->set(handler, dentry, inode, name, value, size, flags);
 }
 
 /*
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 5f61431d8673..62bdb0a6cf2d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1730,7 +1730,8 @@ struct inode_operations {
 			struct inode *, struct dentry *, unsigned int);
 	int (*setattr) (struct dentry *, struct iattr *);
 	int (*getattr) (struct vfsmount *mnt, struct dentry *, struct kstat *);
-	int (*setxattr) (struct dentry *, const char *,const void *,size_t,int);
+	int (*setxattr) (struct dentry *, struct inode *,
+			 const char *, const void *, size_t, int);
 	ssize_t (*getxattr) (struct dentry *, struct inode *,
 			     const char *, void *, size_t);
 	ssize_t (*listxattr) (struct dentry *, char *, size_t);
diff --git a/include/linux/xattr.h b/include/linux/xattr.h
index 76beb206741a..94079bab9243 100644
--- a/include/linux/xattr.h
+++ b/include/linux/xattr.h
@@ -54,7 +54,8 @@ int vfs_removexattr(struct dentry *, const char *);
 
 ssize_t generic_getxattr(struct dentry *dentry, struct inode *inode, const char *name, void *buffer, size_t size);
 ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
-int generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags);
+int generic_setxattr(struct dentry *dentry, struct inode *inode,
+		     const char *name, const void *value, size_t size, int flags);
 int generic_removexattr(struct dentry *dentry, const char *name);
 ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name,
 			   char **xattr_value, size_t size, gfp_t flags);
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index ff2b8c3cf7a9..6777295f4b2b 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3514,7 +3514,7 @@ 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,
+				rc = inode->i_op->setxattr(dp, inode,
 					XATTR_NAME_SMACKTRANSMUTE,
 					TRANS_TRUE, TRANS_TRUE_SIZE,
 					0);
-- 
cgit v1.2.3-58-ga151