1 files changed, 39 insertions, 93 deletions

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index b3fc0a35bf62..5c9d2d80ff70 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)
@@ -511,6 +505,7 @@ static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
 	struct dentry *upper;
 	struct dentry *opaquedir = NULL;
 	int err;
+	int flags = 0;
 
 	if (WARN_ON(!workdir))
 		return -EROFS;
@@ -540,46 +535,39 @@ static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
 	if (err)
 		goto out_dput;
 
-	whiteout = ovl_whiteout(workdir, dentry);
-	err = PTR_ERR(whiteout);
-	if (IS_ERR(whiteout))
+	upper = lookup_one_len(dentry->d_name.name, upperdir,
+			       dentry->d_name.len);
+	err = PTR_ERR(upper);
+	if (IS_ERR(upper))
 		goto out_unlock;
 
-	upper = ovl_dentry_upper(dentry);
-	if (!upper) {
-		upper = lookup_one_len(dentry->d_name.name, upperdir,
-				       dentry->d_name.len);
-		err = PTR_ERR(upper);
-		if (IS_ERR(upper))
-			goto kill_whiteout;
-
-		err = ovl_do_rename(wdir, whiteout, udir, upper, 0);
-		dput(upper);
-		if (err)
-			goto kill_whiteout;
-	} else {
-		int flags = 0;
+	err = -ESTALE;
+	if ((opaquedir && upper != opaquedir) ||
+	    (!opaquedir && ovl_dentry_upper(dentry) &&
+	     upper != ovl_dentry_upper(dentry))) {
+		goto out_dput_upper;
+	}
 
-		if (opaquedir)
-			upper = opaquedir;
-		err = -ESTALE;
-		if (upper->d_parent != upperdir)
-			goto kill_whiteout;
+	whiteout = ovl_whiteout(workdir, dentry);
+	err = PTR_ERR(whiteout);
+	if (IS_ERR(whiteout))
+		goto out_dput_upper;
 
-		if (is_dir)
-			flags |= RENAME_EXCHANGE;
+	if (d_is_dir(upper))
+		flags = RENAME_EXCHANGE;
 
-		err = ovl_do_rename(wdir, whiteout, udir, upper, flags);
-		if (err)
-			goto kill_whiteout;
+	err = ovl_do_rename(wdir, whiteout, udir, upper, flags);
+	if (err)
+		goto kill_whiteout;
+	if (flags)
+		ovl_cleanup(wdir, upper);
 
-		if (is_dir)
-			ovl_cleanup(wdir, upper);
-	}
 	ovl_dentry_version_inc(dentry->d_parent);
 out_d_drop:
 	d_drop(dentry);
 	dput(whiteout);
+out_dput_upper:
+	dput(upper);
 out_unlock:
 	unlock_rename(workdir, upperdir);
 out_dput:
@@ -662,32 +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);
@@ -725,7 +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))
@@ -794,26 +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);
@@ -943,10 +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: