Linux-libre 4.7.1-gnupck-4.7.1-gnu

6 files changed, 55 insertions, 130 deletions

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index cc514da6f..80aa6f1eb 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -336,7 +336,6 @@ int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
 	struct dentry *upperdir;
 	struct dentry *upperdentry;
 	const struct cred *old_cred;
-	struct cred *override_cred;
 	char *link = NULL;
 
 	if (WARN_ON(!workdir))
@@ -357,28 +356,7 @@ int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
 			return PTR_ERR(link);
 	}
 
-	err = -ENOMEM;
-	override_cred = prepare_creds();
-	if (!override_cred)
-		goto out_free_link;
-
-	override_cred->fsuid = stat->uid;
-	override_cred->fsgid = stat->gid;
-	/*
-	 * CAP_SYS_ADMIN for copying up extended attributes
-	 * CAP_DAC_OVERRIDE for create
-	 * CAP_FOWNER for chmod, timestamp update
-	 * CAP_FSETID for chmod
-	 * CAP_CHOWN for chown
-	 * CAP_MKNOD for mknod
-	 */
-	cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
-	cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
-	cap_raise(override_cred->cap_effective, CAP_FOWNER);
-	cap_raise(override_cred->cap_effective, CAP_FSETID);
-	cap_raise(override_cred->cap_effective, CAP_CHOWN);
-	cap_raise(override_cred->cap_effective, CAP_MKNOD);
-	old_cred = override_creds(override_cred);
+	old_cred = ovl_override_creds(dentry->d_sb);
 
 	err = -EIO;
 	if (lock_rename(workdir, upperdir) != NULL) {
@@ -401,9 +379,7 @@ int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
 out_unlock:
 	unlock_rename(workdir, upperdir);
 	revert_creds(old_cred);
-	put_cred(override_cred);
 
-out_free_link:
 	if (link)
 		free_page((unsigned long) link);
 
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index fb35aa21b..5c9d2d80f 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -407,26 +407,20 @@ static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev,
 		const struct cred *old_cred;
 		struct cred *override_cred;
 
+		old_cred = ovl_override_creds(dentry->d_sb);
+
 		err = -ENOMEM;
 		override_cred = prepare_creds();
-		if (!override_cred)
-			goto out_iput;
-
-		/*
-		 * CAP_SYS_ADMIN for setting opaque xattr
-		 * CAP_DAC_OVERRIDE for create in workdir, rename
-		 * CAP_FOWNER for removing whiteout from sticky dir
-		 */
-		cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
-		cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
-		cap_raise(override_cred->cap_effective, CAP_FOWNER);
-		old_cred = override_creds(override_cred);
-
-		err = ovl_create_over_whiteout(dentry, inode, &stat, link,
-					       hardlink);
-
+		if (override_cred) {
+			override_cred->fsuid = old_cred->fsuid;
+			override_cred->fsgid = old_cred->fsgid;
+			put_cred(override_creds(override_cred));
+			put_cred(override_cred);
+
+			err = ovl_create_over_whiteout(dentry, inode, &stat,
+						       link, hardlink);
+		}
 		revert_creds(old_cred);
-		put_cred(override_cred);
 	}
 
 	if (!err)
@@ -656,32 +650,11 @@ static int ovl_do_remove(struct dentry *dentry, bool is_dir)
 	if (OVL_TYPE_PURE_UPPER(type)) {
 		err = ovl_remove_upper(dentry, is_dir);
 	} else {
-		const struct cred *old_cred;
-		struct cred *override_cred;
-
-		err = -ENOMEM;
-		override_cred = prepare_creds();
-		if (!override_cred)
-			goto out_drop_write;
-
-		/*
-		 * CAP_SYS_ADMIN for setting xattr on whiteout, opaque dir
-		 * CAP_DAC_OVERRIDE for create in workdir, rename
-		 * CAP_FOWNER for removing whiteout from sticky dir
-		 * CAP_FSETID for chmod of opaque dir
-		 * CAP_CHOWN for chown of opaque dir
-		 */
-		cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
-		cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
-		cap_raise(override_cred->cap_effective, CAP_FOWNER);
-		cap_raise(override_cred->cap_effective, CAP_FSETID);
-		cap_raise(override_cred->cap_effective, CAP_CHOWN);
-		old_cred = override_creds(override_cred);
+		const struct cred *old_cred = ovl_override_creds(dentry->d_sb);
 
 		err = ovl_remove_and_whiteout(dentry, is_dir);
 
 		revert_creds(old_cred);
-		put_cred(override_cred);
 	}
 out_drop_write:
 	ovl_drop_write(dentry);
@@ -719,7 +692,6 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
 	bool new_is_dir = false;
 	struct dentry *opaquedir = NULL;
 	const struct cred *old_cred = NULL;
-	struct cred *override_cred = NULL;
 
 	err = -EINVAL;
 	if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
@@ -788,26 +760,8 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
 	old_opaque = !OVL_TYPE_PURE_UPPER(old_type);
 	new_opaque = !OVL_TYPE_PURE_UPPER(new_type);
 
-	if (old_opaque || new_opaque) {
-		err = -ENOMEM;
-		override_cred = prepare_creds();
-		if (!override_cred)
-			goto out_drop_write;
-
-		/*
-		 * CAP_SYS_ADMIN for setting xattr on whiteout, opaque dir
-		 * CAP_DAC_OVERRIDE for create in workdir
-		 * CAP_FOWNER for removing whiteout from sticky dir
-		 * CAP_FSETID for chmod of opaque dir
-		 * CAP_CHOWN for chown of opaque dir
-		 */
-		cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
-		cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
-		cap_raise(override_cred->cap_effective, CAP_FOWNER);
-		cap_raise(override_cred->cap_effective, CAP_FSETID);
-		cap_raise(override_cred->cap_effective, CAP_CHOWN);
-		old_cred = override_creds(override_cred);
-	}
+	if (old_opaque || new_opaque)
+		old_cred = ovl_override_creds(old->d_sb);
 
 	if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) {
 		opaquedir = ovl_check_empty_and_clear(new);
@@ -937,10 +891,8 @@ out_dput_old:
 out_unlock:
 	unlock_rename(new_upperdir, old_upperdir);
 out_revert_creds:
-	if (old_opaque || new_opaque) {
+	if (old_opaque || new_opaque)
 		revert_creds(old_cred);
-		put_cred(override_cred);
-	}
 out_drop_write:
 	ovl_drop_write(old);
 out:
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index d46fa609e..d1cdc60dd 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -236,8 +236,9 @@ 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;
@@ -263,41 +264,27 @@ out:
 	return err;
 }
 
-static bool ovl_need_xattr_filter(struct dentry *dentry,
-				  enum ovl_path_type type)
+ssize_t ovl_getxattr(struct dentry *dentry, struct inode *inode,
+		     const char *name, void *value, size_t size)
 {
-	if ((type & (__OVL_PATH_PURE | __OVL_PATH_UPPER)) == __OVL_PATH_UPPER)
-		return S_ISDIR(dentry->d_inode->i_mode);
-	else
-		return false;
-}
-
-ssize_t ovl_getxattr(struct dentry *dentry, const char *name,
-		     void *value, size_t size)
-{
-	struct path realpath;
-	enum ovl_path_type type = ovl_path_real(dentry, &realpath);
+	struct dentry *realdentry = ovl_dentry_real(dentry);
 
-	if (ovl_need_xattr_filter(dentry, type) && ovl_is_private_xattr(name))
+	if (ovl_is_private_xattr(name))
 		return -ENODATA;
 
-	return vfs_getxattr(realpath.dentry, name, value, size);
+	return vfs_getxattr(realdentry, name, value, size);
 }
 
 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
 {
-	struct path realpath;
-	enum ovl_path_type type = ovl_path_real(dentry, &realpath);
+	struct dentry *realdentry = ovl_dentry_real(dentry);
 	ssize_t res;
 	int off;
 
-	res = vfs_listxattr(realpath.dentry, list, size);
+	res = vfs_listxattr(realdentry, list, size);
 	if (res <= 0 || size == 0)
 		return res;
 
-	if (!ovl_need_xattr_filter(dentry, type))
-		return res;
-
 	/* filter out private xattrs */
 	for (off = 0; off < res;) {
 		char *s = list + off;
@@ -327,7 +314,7 @@ int ovl_removexattr(struct dentry *dentry, const char *name)
 		goto out;
 
 	err = -ENODATA;
-	if (ovl_need_xattr_filter(dentry, type) && ovl_is_private_xattr(name))
+	if (ovl_is_private_xattr(name))
 		goto out_drop_write;
 
 	if (!OVL_TYPE_UPPER(type)) {
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 294ccc0c1..cfbca5359 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -153,6 +153,7 @@ void ovl_drop_write(struct dentry *dentry);
 bool ovl_dentry_is_opaque(struct dentry *dentry);
 void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque);
 bool ovl_is_whiteout(struct dentry *dentry);
+const struct cred *ovl_override_creds(struct super_block *sb);
 void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry);
 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 			  unsigned int flags);
@@ -171,10 +172,11 @@ 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);
-ssize_t ovl_getxattr(struct dentry *dentry, const char *name,
-		     void *value, size_t size);
+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);
 int ovl_removexattr(struct dentry *dentry, const char *name);
 struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags);
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 6ec1e43a9..cf37fc76f 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -36,6 +36,7 @@ struct ovl_dir_cache {
 
 struct ovl_readdir_data {
 	struct dir_context ctx;
+	struct dentry *dentry;
 	bool is_lowest;
 	struct rb_root root;
 	struct list_head *list;
@@ -206,19 +207,10 @@ static int ovl_check_whiteouts(struct dentry *dir, struct ovl_readdir_data *rdd)
 	struct ovl_cache_entry *p;
 	struct dentry *dentry;
 	const struct cred *old_cred;
-	struct cred *override_cred;
-
-	override_cred = prepare_creds();
-	if (!override_cred)
-		return -ENOMEM;
 
-	/*
-	 * CAP_DAC_OVERRIDE for lookup
-	 */
-	cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
-	old_cred = override_creds(override_cred);
+	old_cred = ovl_override_creds(rdd->dentry->d_sb);
 
-	err = mutex_lock_killable(&dir->d_inode->i_mutex);
+	err = down_write_killable(&dir->d_inode->i_rwsem);
 	if (!err) {
 		while (rdd->first_maybe_whiteout) {
 			p = rdd->first_maybe_whiteout;
@@ -232,7 +224,6 @@ static int ovl_check_whiteouts(struct dentry *dir, struct ovl_readdir_data *rdd)
 		inode_unlock(dir->d_inode);
 	}
 	revert_creds(old_cred);
-	put_cred(override_cred);
 
 	return err;
 }
@@ -288,6 +279,7 @@ static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list)
 	struct path realpath;
 	struct ovl_readdir_data rdd = {
 		.ctx.actor = ovl_fill_merge,
+		.dentry = dentry,
 		.list = list,
 		.root = RB_ROOT,
 		.is_lowest = false,
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 7952a50f0..9a7693d5f 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -42,6 +42,8 @@ struct ovl_fs {
 	long lower_namelen;
 	/* pathnames of lower and upper dirs, for show_options */
 	struct ovl_config config;
+	/* creds of process who forced instantiation of super block */
+	const struct cred *creator_cred;
 };
 
 struct ovl_dir_cache;
@@ -265,6 +267,13 @@ bool ovl_is_whiteout(struct dentry *dentry)
 	return inode && IS_WHITEOUT(inode);
 }
 
+const struct cred *ovl_override_creds(struct super_block *sb)
+{
+	struct ovl_fs *ofs = sb->s_fs_info;
+
+	return override_creds(ofs->creator_cred);
+}
+
 static bool ovl_is_opaquedir(struct dentry *dentry)
 {
 	int res;
@@ -274,7 +283,7 @@ static bool ovl_is_opaquedir(struct dentry *dentry)
 	if (!S_ISDIR(inode->i_mode) || !inode->i_op->getxattr)
 		return false;
 
-	res = inode->i_op->getxattr(dentry, OVL_XATTR_OPAQUE, &val, 1);
+	res = inode->i_op->getxattr(dentry, inode, OVL_XATTR_OPAQUE, &val, 1);
 	if (res == 1 && val == 'y')
 		return true;
 
@@ -603,6 +612,7 @@ static void ovl_put_super(struct super_block *sb)
 	kfree(ufs->config.lowerdir);
 	kfree(ufs->config.upperdir);
 	kfree(ufs->config.workdir);
+	put_cred(ufs->creator_cred);
 	kfree(ufs);
 }
 
@@ -1113,10 +1123,14 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 	else
 		sb->s_d_op = &ovl_dentry_operations;
 
+	ufs->creator_cred = prepare_creds();
+	if (!ufs->creator_cred)
+		goto out_put_lower_mnt;
+
 	err = -ENOMEM;
 	oe = ovl_alloc_entry(numlower);
 	if (!oe)
-		goto out_put_lower_mnt;
+		goto out_put_cred;
 
 	root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, oe));
 	if (!root_dentry)
@@ -1149,6 +1163,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 
 out_free_oe:
 	kfree(oe);
+out_put_cred:
+	put_cred(ufs->creator_cred);
 out_put_lower_mnt:
 	for (i = 0; i < ufs->numlower; i++)
 		mntput(ufs->lower_mnt[i]);