Re: [RFC PATCH v2 5/9] fs: add anon_inode_getfile_secure() similar to anon_inode_getfd_secure()

On 11/08/2021 22:48, Paul Moore wrote: > Extending the secure anonymous inode support to other subsystems > requires that we have a secure anon_inode_getfile() variant in > addition to the existing secure anon_inode_getfd() variant. > > Thankfully we can reuse the existing __anon_inode_getfile() function > and just wrap it with the proper arguments. > > Signed-off-by: Paul Moore <paul(a)paul-moore.com&gt; > > --- > v2: > - no change > v1: > - initial draft > --- > fs/anon_inodes.c | 29 +++++++++++++++++++++++++++++ > include/linux/anon_inodes.h | 4 ++++ > 2 files changed, 33 insertions(+) > > diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c > index a280156138ed..e0c3e33c4177 100644 > --- a/fs/anon_inodes.c > +++ b/fs/anon_inodes.c > @@ -148,6 +148,35 @@ struct file *anon_inode_getfile(const char *name, > } > EXPORT_SYMBOL_GPL(anon_inode_getfile); > > +/** > + * anon_inode_getfile_secure - Like anon_inode_getfile(), but creates a new > + * !S_PRIVATE anon inode rather than reuse the > + * singleton anon inode and calls the > + * inode_init_security_anon() LSM hook. This > + * allows for both the inode to have its own > + * security context and for the LSM to enforce > + * policy on the inode's creation. > + * > + * @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 > + * @context_inode: > + * [in] the logical relationship with the new inode (optional) > + * > + * The LSM may use @context_inode in inode_init_security_anon(), but a > + * reference to it is not held. Returns the newly created file* or an error > + * pointer. See the anon_inode_getfile() documentation for more information. > + */ > +struct file *anon_inode_getfile_secure(const char *name, > + const struct file_operations *fops, > + void *priv, int flags, > + const struct inode *context_inode) > +{ > + return __anon_inode_getfile(name, fops, priv, flags, > + context_inode, true); This is not directly related to this patch but why using the "secure" boolean in __anon_inode_getfile() and __anon_inode_getfd() instead of checking that context_inode is not NULL? This would simplify the code, remove this anon_inode_getfile_secure() wrapper and avoid potential inconsistencies.