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39. Capabilities > Transformation of Process Capabilities During exec()

Transformation of Process Capabilities During exec()

During an exec(), the kernel sets new capabilities for the process based on the process’s current capabilities and the capability sets of the file being executed. The kernel calculates the new capabilities of the process using the following rules:

P'(permitted) = (P(inheritable) & F(inheritable)) | (F(permitted) & cap_bset)

P'(effective) = F(effective) ? P'(permitted) : 0

P'(inheritable) = P(inheritable)

In the above rules, P denotes the value of a capability set prior to the exec(), P’ denotes the value of a capability set after the exec(), and F denotes a file capability set. The identifier cap_bset denotes the value of the capability bounding set. Note that exec() leaves the process inheritable capability set unchanged.


  

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