Commit f88c5942 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'ovl-update-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 

Pull overlayfs updates from Miklos Szeredi:
 "Fix copy up of security related xattrs"

* tag 'ovl-update-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: Do not lose security.capability xattr over metadata file copy-up
  ovl: During copy up, first copy up data and then xattrs
parents dfee9c25 993a0b2a

fs/overlayfs/copy_up.c

+44 −15
Original line number Diff line number Diff line
@@ -443,6 +443,24 @@ static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp) 
{

	int err;



	/*

	 * Copy up data first and then xattrs. Writing data after

	 * xattrs will remove security.capability xattr automatically.

	 */

	if (S_ISREG(c->stat.mode) && !c->metacopy) {

		struct path upperpath, datapath;



		ovl_path_upper(c->dentry, &upperpath);

		if (WARN_ON(upperpath.dentry != NULL))

			return -EIO;

		upperpath.dentry = temp;



		ovl_path_lowerdata(c->dentry, &datapath);

		err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);

		if (err)

			return err;

	}



	err = ovl_copy_xattr(c->lowerpath.dentry, temp);

	if (err)

		return err;
@@ -460,19 +478,6 @@ static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp) 
			return err;

	}



	if (S_ISREG(c->stat.mode) && !c->metacopy) {

		struct path upperpath, datapath;



		ovl_path_upper(c->dentry, &upperpath);

		BUG_ON(upperpath.dentry != NULL);

		upperpath.dentry = temp;



		ovl_path_lowerdata(c->dentry, &datapath);

		err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);

		if (err)

			return err;

	}



	if (c->metacopy) {

		err = ovl_check_setxattr(c->dentry, temp, OVL_XATTR_METACOPY,

					 NULL, 0, -EOPNOTSUPP);
@@ -737,6 +742,8 @@ static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c) 
{

	struct path upperpath, datapath;

	int err;

	char *capability = NULL;

	ssize_t uninitialized_var(cap_size);



	ovl_path_upper(c->dentry, &upperpath);

	if (WARN_ON(upperpath.dentry == NULL))
@@ -746,15 +753,37 @@ static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c) 
	if (WARN_ON(datapath.dentry == NULL))

		return -EIO;



	if (c->stat.size) {

		err = cap_size = ovl_getxattr(upperpath.dentry, XATTR_NAME_CAPS,

					      &capability, 0);

		if (err < 0 && err != -ENODATA)

			goto out;

	}



	err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);

	if (err)

		return err;

		goto out_free;



	/*

	 * Writing to upper file will clear security.capability xattr. We

	 * don't want that to happen for normal copy-up operation.

	 */

	if (capability) {

		err = ovl_do_setxattr(upperpath.dentry, XATTR_NAME_CAPS,

				      capability, cap_size, 0);

		if (err)

			goto out_free;

	}





	err = vfs_removexattr(upperpath.dentry, OVL_XATTR_METACOPY);

	if (err)

		return err;

		goto out_free;



	ovl_set_upperdata(d_inode(c->dentry));

out_free:

	kfree(capability);

out:

	return err;

}

fs/overlayfs/overlayfs.h

+2 −0
Original line number Diff line number Diff line
@@ -277,6 +277,8 @@ int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir); 
int ovl_check_metacopy_xattr(struct dentry *dentry);

bool ovl_is_metacopy_dentry(struct dentry *dentry);

char *ovl_get_redirect_xattr(struct dentry *dentry, int padding);

ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,

		     size_t padding);



static inline bool ovl_is_impuredir(struct dentry *dentry)

{

fs/overlayfs/util.c

+35 −20
Original line number Diff line number Diff line
@@ -863,28 +863,49 @@ bool ovl_is_metacopy_dentry(struct dentry *dentry) 
	return (oe->numlower > 1);

}



char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)

ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,

		     size_t padding)

{

	int res;

	char *s, *next, *buf = NULL;

	ssize_t res;

	char *buf = NULL;



	res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, NULL, 0);

	res = vfs_getxattr(dentry, name, NULL, 0);

	if (res < 0) {

		if (res == -ENODATA || res == -EOPNOTSUPP)

			return NULL;

			return -ENODATA;

		goto fail;

	}



	buf = kzalloc(res + padding + 1, GFP_KERNEL);

	if (res != 0) {

		buf = kzalloc(res + padding, GFP_KERNEL);

		if (!buf)

		return ERR_PTR(-ENOMEM);

			return -ENOMEM;



	if (res == 0)

		goto invalid;



	res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, buf, res);

		res = vfs_getxattr(dentry, name, buf, res);

		if (res < 0)

			goto fail;

	}

	*value = buf;



	return res;



fail:

	pr_warn_ratelimited("overlayfs: failed to get xattr %s: err=%zi)\n",

			    name, res);

	kfree(buf);

	return res;

}



char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)

{

	int res;

	char *s, *next, *buf = NULL;



	res = ovl_getxattr(dentry, OVL_XATTR_REDIRECT, &buf, padding + 1);

	if (res == -ENODATA)

		return NULL;

	if (res < 0)

		return ERR_PTR(res);

	if (res == 0)

		goto invalid;
@@ -900,15 +921,9 @@ char *ovl_get_redirect_xattr(struct dentry *dentry, int padding) 
	}



	return buf;



err_free:

	kfree(buf);

	return ERR_PTR(res);

fail:

	pr_warn_ratelimited("overlayfs: failed to get redirect (%i)\n", res);

	goto err_free;

invalid:

	pr_warn_ratelimited("overlayfs: invalid redirect (%s)\n", buf);

	res = -EINVAL;

	goto err_free;

	kfree(buf);

	return ERR_PTR(res);

}

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