Re: WARNING in __kernel_read

[Kees Cook]

On Wed, Oct 06, 2021 at 09:57:22AM -0400, Theodore Ts'o wrote:
> On Wed, Oct 06, 2021 at 01:17:32PM +0100, Matthew Wilcox wrote:
> > finit_module() is not the only caller of kernel_read_file_from_fd()
> > which passes it a fd that userspace passed in, for example
> > kexec_file_load() doesn't validate the fd either.  We could validate
> > the fd in individual syscalls, in kernel_read_file_from_fd()
> > or just do what vfs_read() does and return -EBADF without warning.
> 
> My suggestion would be to do both, and keep a WARN() in
> __kernel_read(), since that should never happen (and we want a stack
> trace if it does).

Agreed.

-- 
Kees Cook