On 3/26/20 2:14 PM, Daniel Colascione wrote:
This change adds two new functions, anon_inode_getfile_secure and
anon_inode_getfd_secure, that create anonymous-node files with
individual non-S_PRIVATE inodes to which security modules can apply
policy. Existing callers continue using the original singleton-inode
kind of anonymous-inode file. We can transition anonymous inode users
to the new kind of anonymous inode in individual patches for the sake
of bisection and review.
The new functions accept an optional context_inode parameter that
callers can use to provide additional contextual information to
security modules, e.g., indicating that one anonymous struct file is a
logical child of another, allowing a security model to propagate
security information from one to the other.
Signed-off-by: Daniel Colascione <dancol@xxxxxxxxxx>
---
Repeating verbatim what I said on v2 of patch 1/3.
diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c
index 89714308c25b..114a04fc1db4 100644
--- a/fs/anon_inodes.c
+++ b/fs/anon_inodes.c
@@ -55,75 +55,135 @@ static struct file_system_type anon_inode_fs_type = {
.kill_sb = kill_anon_super,
};
-/**
- * anon_inode_getfile - creates a new file instance by hooking it up to an
- * anonymous inode, and a dentry that describe the "class"
- * of the file
- *
- * @name: [in] name of the "class" of the new file
- * @fops: [in] file operations for the new file
- * @priv: [in] private data for the new file (will be file's private_data)
- * @flags: [in] flags
- *
- * Creates a new file by hooking it on a single inode. This is useful for files
- * that do not need to have a full-fledged inode in order to operate correctly.
- * All the files created with anon_inode_getfile() will share a single inode,
- * hence saving memory and avoiding code duplication for the file/inode/dentry
- * setup. Returns the newly created file* or an error pointer.
- */
-struct file *anon_inode_getfile(const char *name,
- const struct file_operations *fops,
- void *priv, int flags)
+static struct inode *anon_inode_make_secure_inode(
+ const char *name,
+ const struct inode *context_inode,
+ const struct file_operations *fops)
+{
+ struct inode *inode;
+ const struct qstr qname = QSTR_INIT(name, strlen(name));
+ int error;
+
+ inode = alloc_anon_inode(anon_inode_mnt->mnt_sb);
+ if (IS_ERR(inode))
+ return ERR_PTR(PTR_ERR(inode));
Just return inode here ?
+ inode->i_flags &= ~S_PRIVATE;
+ error = security_inode_init_security_anon(
+ inode, &qname, fops, context_inode);
Would drop fops argument until we have a real user for it; we can always
add it later.
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 37df7c9eedb1..07b0f6e03849 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1014,8 +1014,6 @@ static __poll_t userfaultfd_poll(struct file *file, poll_table *wait)
}
}
-static const struct file_operations userfaultfd_fops;
-
static int resolve_userfault_fork(struct userfaultfd_ctx *ctx,
struct userfaultfd_ctx *new,
struct uffd_msg *msg)
@@ -1920,7 +1918,7 @@ static void userfaultfd_show_fdinfo(struct seq_file *m, struct file *f)
}
#endif
-static const struct file_operations userfaultfd_fops = {
+const struct file_operations userfaultfd_fops = {
#ifdef CONFIG_PROC_FS
.show_fdinfo = userfaultfd_show_fdinfo,
#endif
These changes are unnecessary for this patch and reverted by patch 3, so
drop them here.
