In message <20071022082231.GA15132@infradead.org>, Christoph Hellwig writes:
Why? Are you concerned that the security policy may change after a module
is loaded? My understanding of the security code is that it should handle
this, even if people call security_*() functions directly. When I look at
the security_* functions in security.c, to me they very much smell like
global wrappers that others can call, b/c they refer to private/global ops
vectors that one should not be referencing directly. For example:
int security_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
return security_ops->file_ioctl(file, cmd, arg);
}
I can probably get rid of having unionfs call security_inode_permission, by
calling permission() myself and carefully post-process its return code
(unionfs needs to "ignore" EROFS initially, to allow copyup to take place).
But security_file_ioctl doesn't have any existing helper I can call. I can
introduce a trivial vfs_security_file_ioctl wrapper to security_file_ioctl,
but what about the already existing *19* exported security_* functions in
security/security.c? Do you want to see simple wrappers for all of them?
It seems redundant to add a one-line wrapper around an already one-line
function around security_ops->XXX. Plus, some of the existing exported
security_* functions are file-system related, others are networking, etc. So
we'll need wrappers whose names are prefixed appropriately: vfs_*, net_*,
etc.
Thanks,
Erez.
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