Commit 55956b59 authored May 23, 2018 by Eric W. Biederman

vfs: Allow userns root to call mknod on owned filesystems.



These filesystems already always set SB_I_NODEV so mknod will not be
useful for gaining control of any devices no matter their permissions.
This will allow overlayfs and applications like to fakeroot to use
device nodes to represent things on disk.

Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

parent 593d1ce8

fs/namei.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -3679,7 +3679,8 @@ int vfs_mknod(struct inode dir, struct dentry dentry, umode_t mode, dev_t dev)
		if (error)
		return error;

		if ((S_ISCHR(mode) \|\| S_ISBLK(mode)) && !capable(CAP_MKNOD))
		if ((S_ISCHR(mode) \|\| S_ISBLK(mode)) &&
		!ns_capable(dentry->d_sb->s_user_ns, CAP_MKNOD))
		return -EPERM;

		if (!dir->i_op->mknod)

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