On 3/26/2024 12:40 PM, Christian Brauner wrote:
we can change the parameter of security_path_post_mknod() from
dentry to inode?
If all current callers only operate on the inode then it seems the best
to only pass the inode. If there's some reason someone later needs a
dentry the hook can always be changed.
Ok, so the crash is likely caused by:
void security_path_post_mknod(struct mnt_idmap *idmap, struct dentry
*dentry)
{
if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
I guess we can also simply check if there is an inode attached to the
dentry, to minimize the changes. I can do both.
More technical question, do I need to do extra checks on the dentry
before calling security_path_post_mknod()?
Thanks
Roberto
For bigger changes it's also worthwhile if the object that's passed down
into the hook-based LSM layer is as specific as possible. If someone
does a change that affects lifetime rules of mounts then any hook that
takes a struct path argument that's unused means going through each LSM
that implements the hook only to find out it's not actually used.
Similar for dentry vs inode imho.
