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Commit 2b6bc7f4 authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

ovl: lookup: do getxattr with mounter's permission 



The getxattr() in ovl_is_opaquedir() was missed when converting all
operations on underlying fs to be done under mounter's permission.

This patch fixes this by moving the ovl_override_creds()/revert_creds() out
from ovl_lookup_real() to ovl_lookup().

Also convert to using vfs_getxattr() instead of directly calling
i_op->getxattr().

Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 8b326c61

fs/overlayfs/super.c

+9 −11
Original line number Diff line number Diff line
@@ -273,12 +273,11 @@ static bool ovl_is_opaquedir(struct dentry *dentry) 
{

	int res;

	char val;

	struct inode *inode = dentry->d_inode;



	if (!S_ISDIR(inode->i_mode) || !inode->i_op->getxattr)

	if (!d_is_dir(dentry))

		return false;



	res = inode->i_op->getxattr(dentry, inode, OVL_XATTR_OPAQUE, &val, 1);

	res = vfs_getxattr(dentry, OVL_XATTR_OPAQUE, &val, 1);

	if (res == 1 && val == 'y')

		return true;
@@ -419,16 +418,12 @@ static bool ovl_dentry_weird(struct dentry *dentry) 
				  DCACHE_OP_COMPARE);

}



static inline struct dentry *ovl_lookup_real(struct super_block *ovl_sb,

					     struct dentry *dir,

static inline struct dentry *ovl_lookup_real(struct dentry *dir,

					     const struct qstr *name)

{

	const struct cred *old_cred;

	struct dentry *dentry;



	old_cred = ovl_override_creds(ovl_sb);

	dentry = lookup_one_len_unlocked(name->name, dir, name->len);

	revert_creds(old_cred);



	if (IS_ERR(dentry)) {

		if (PTR_ERR(dentry) == -ENOENT)
@@ -469,6 +464,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 
			  unsigned int flags)

{

	struct ovl_entry *oe;

	const struct cred *old_cred;

	struct ovl_entry *poe = dentry->d_parent->d_fsdata;

	struct path *stack = NULL;

	struct dentry *upperdir, *upperdentry = NULL;
@@ -479,9 +475,10 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 
	unsigned int i;

	int err;



	old_cred = ovl_override_creds(dentry->d_sb);

	upperdir = ovl_upperdentry_dereference(poe);

	if (upperdir) {

		this = ovl_lookup_real(dentry->d_sb, upperdir, &dentry->d_name);

		this = ovl_lookup_real(upperdir, &dentry->d_name);

		err = PTR_ERR(this);

		if (IS_ERR(this))

			goto out;
@@ -514,8 +511,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 
		bool opaque = false;

		struct path lowerpath = poe->lowerstack[i];



		this = ovl_lookup_real(dentry->d_sb,

				       lowerpath.dentry, &dentry->d_name);

		this = ovl_lookup_real(lowerpath.dentry, &dentry->d_name);

		err = PTR_ERR(this);

		if (IS_ERR(this)) {

			/*
@@ -588,6 +584,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 
		ovl_copyattr(realdentry->d_inode, inode);

	}



	revert_creds(old_cred);

	oe->opaque = upperopaque;

	oe->__upperdentry = upperdentry;

	memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr);
@@ -606,6 +603,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 
out_put_upper:

	dput(upperdentry);

out:

	revert_creds(old_cred);

	return ERR_PTR(err);

}