Re: [RFC 2/2] binfmt_misc: move data to binfmt_namespace
From: Jann Horn <jannh@google.com>
Date: 2018-10-01 08:54:14
Also in:
linux-fsdevel, lkml
On Mon, Oct 1, 2018 at 1:47 AM Laurent Vivier [off-list ref] wrote:
quoted hunk ↗ jump to hunk
@@ -716,7 +711,8 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer, if (!inode) goto out2; - err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); + err = simple_pin_fs(&bm_fs_type, &binfmt_ns(bm_mnt), + &binfmt_ns(entry_count)); if (err) { iput(inode); inode = NULL;@@ -730,7 +726,8 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer, if (IS_ERR(f)) { err = PTR_ERR(f); pr_notice("register: failed to install interpreter file %s\n", e->interpreter); - simple_release_fs(&bm_mnt, &entry_count); + simple_release_fs(&binfmt_ns(bm_mnt), + &binfmt_ns(entry_count)); iput(inode); inode = NULL; goto out2;@@ -743,9 +740,9 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer, inode->i_fop = &bm_entry_operations; d_instantiate(dentry, inode); - write_lock(&entries_lock); - list_add(&e->list, &entries); - write_unlock(&entries_lock); + write_lock(&binfmt_ns(entries_lock)); + list_add(&e->list, &binfmt_ns(entries)); + write_unlock(&binfmt_ns(entries_lock));
This looks wrong. A write handler's behavior should not depend on the namespace of the process that is using it. Ideally, the affected namespace should depend on the file you're writing to. If that's not possible, the affected namespace should at least be the namespace of the process that opened the file.