Messages in this thread | | | Subject | Re: [TOMOYO #5 02/18] Add wrapper functions for VFShelperfunctions. | From | Tetsuo Handa <> | Date | Sat, 17 Nov 2007 14:23:56 +0900 |
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Hello.
Trond Myklebust wrote: > I'm confused. How do you tell the difference between a 'userland' > request and a 'kernel' request, and why is the latter safe from a > security perspective? For example, if userland process wants to create a directory, it will call mkdir(2). In the kernel, mkdir(2) is mapped to sys_mkdir(), sys_mkdir() calls sys_mkdirat(), sys_mkdirat() calls vfs_mkdir().
Therefore, there is a chance to tell whether vfs_mkdir() is triggered by userland process's request. Some kernel code *might* call sys_mkdir() too. But at least I think I can hook all requests triggered by userland process's request because routes to call vfs_mkdir() from userland is not infinite.
We are regarding the kernel code as trusted. For example, no security checks for code that are called by only kernel. http://www.mail-archive.com/linux-security-module@vger.kernel.org/msg01830.html
Regards.
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