Commit 979086f5 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'fs.fixes.v5.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux 

Pull vfs idmapping fix from Christian Brauner:
 "This fixes an issue where we fail to change the group of a file when
  the caller owns the file and is a member of the group to change to.

  This is only relevant on idmapped mounts.

  There's a detailed description in the commit message and regression
  tests have been added to xfstests"

* tag 'fs.fixes.v5.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  fs: account for group membership
parents 018ab4fa 168f9128

fs/attr.c

+20 −6
Original line number Diff line number Diff line
@@ -61,9 +61,15 @@ static bool chgrp_ok(struct user_namespace *mnt_userns, 
		     const struct inode *inode, kgid_t gid)

{

	kgid_t kgid = i_gid_into_mnt(mnt_userns, inode);

	if (uid_eq(current_fsuid(), i_uid_into_mnt(mnt_userns, inode)) &&

	    (in_group_p(gid) || gid_eq(gid, inode->i_gid)))

	if (uid_eq(current_fsuid(), i_uid_into_mnt(mnt_userns, inode))) {

		kgid_t mapped_gid;



		if (gid_eq(gid, inode->i_gid))

			return true;

		mapped_gid = mapped_kgid_fs(mnt_userns, i_user_ns(inode), gid);

		if (in_group_p(mapped_gid))

			return true;

	}

	if (capable_wrt_inode_uidgid(mnt_userns, inode, CAP_CHOWN))

		return true;

	if (gid_eq(kgid, INVALID_GID) &&
@@ -123,11 +129,19 @@ int setattr_prepare(struct user_namespace *mnt_userns, struct dentry *dentry, 


	/* Make sure a caller can chmod. */

	if (ia_valid & ATTR_MODE) {

		kgid_t mapped_gid;



		if (!inode_owner_or_capable(mnt_userns, inode))

			return -EPERM;



		if (ia_valid & ATTR_GID)

			mapped_gid = mapped_kgid_fs(mnt_userns,

						i_user_ns(inode), attr->ia_gid);

		else

			mapped_gid = i_gid_into_mnt(mnt_userns, inode);



		/* Also check the setgid bit! */

               if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :

                                i_gid_into_mnt(mnt_userns, inode)) &&

		if (!in_group_p(mapped_gid) &&

		    !capable_wrt_inode_uidgid(mnt_userns, inode, CAP_FSETID))

			attr->ia_mode &= ~S_ISGID;

	}