mm/secretmem: fix panic when growing a memfd_secret

[linux-2.6-microblaze.git] / mm / secretmem.c

diff --git a/mm/secretmem.c b/mm/secretmem.c
index 098638d..3b3cf28 100644 (file)
--- a/mm/secretmem.c
+++ b/mm/secretmem.c
@@ -158,6 +158,22 @@ const struct address_space_operations secretmem_aops = {
        .isolate_page   = secretmem_isolate_page,
 };
 
+static int secretmem_setattr(struct user_namespace *mnt_userns,
+                            struct dentry *dentry, struct iattr *iattr)
+{
+       struct inode *inode = d_inode(dentry);
+       unsigned int ia_valid = iattr->ia_valid;
+
+       if ((ia_valid & ATTR_SIZE) && inode->i_size)
+               return -EINVAL;
+
+       return simple_setattr(mnt_userns, dentry, iattr);
+}
+
+static const struct inode_operations secretmem_iops = {
+       .setattr = secretmem_setattr,
+};
+
 static struct vfsmount *secretmem_mnt;
 
 static struct file *secretmem_file_create(unsigned long flags)
@@ -177,6 +193,7 @@ static struct file *secretmem_file_create(unsigned long flags)
        mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER);
        mapping_set_unevictable(inode->i_mapping);
 
+       inode->i_op = &secretmem_iops;
        inode->i_mapping->a_ops = &secretmem_aops;
 
        /* pretend we are a normal file with zero size */