Re: [PATCH] ipc/sem: Avoid indexing past end of sem_array

[Manfred Spraul]

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Hi Kees,

On 05/09/2017 12:23 AM, Kees Cook wrote:
> This changes the struct + trailing data pattern to using a void * so that
> the end of sem_array is found without possibly indexing past the end which
> can upset some static analyzers. Mostly, this ends up avoiding a cast
> between different non-void types, which the future randstruct GCC plugin
> was warning about.
Two question:
- Would the attached patch work with the randstruct plugin as well?
  If we touch the code, then I would propose that we remove sem_base 
entirely.

- ipc/util.h contains

> #define ipc_rcu_to_struct(p)  ((void *)(p+1))

Does this trigger a warning with randstruct as well?
If we have to touch it, then I would remove it by merging struct 
kern_ipc_perm and struct ipc_rcu.

And, obviously:
Do you see any issues with the attached patch?
--
    Manfred