Re: Append vs. write distinctions

chrisat_private

* Stephen Smalley (sdsat_private) wrote:
<snip>

> Some possible solutions:
> 
> 1) Change the computation of acc_mode in open_namei() to retain
> the O_APPEND flag if it is in flags.  In the permission() function,
> call the LSM permission security hook with this expanded access mode so
> that it can distinguish append access from write access.  After calling
> the LSM permission security hook, reduce the access mode to the
> traditional read/write/execute modes before performing the normal
> Linux checking (i.e. the call to the inode permission operation
> or the call to vfs_permission).  OR
> 
> 2) Change the IS_APPEND (and IS_IMMUTABLE and perhaps other) macros to
> also call a LSM security hook when the check is performed so that the
> security module has the option of performing a check at this point based
> on both the process and the file.

Do you have a preference?

-chris

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