Re: [PATCH 3/4] security: capabilities patch (version 0.4.4), part 3/4: introduce new capabilities

Jan Engelhardt
2006-09-11T06:12:37Z

>> To expand on this a little, some of the capabilities you are looking to
>> add are of very little if any use without being able to specify objects.
>> For example, CAP_REG_OPEN is whether the process can open any file
>> instead of specific ones. How many applications open no files whatsoever
>> in practice? Even if there are some as soon as they change and need to
>> open a file they'll need this capability and will be able to open any.
>> CAP_REG_WRITE has the same problem. For a description of why
>> CAP_REG_EXEC is meaningless see the digsig thread on the LSM list from
>> earlier this year.
>
>CAP_REG_OPEN and CAP_REG_EXEC might be useful only for demonstration
>purposes, but I've *often* wished I could run a program without

You cannot reasonable run a program without CAP_REG_OPEN, because
ld.so, libc.so and libdl.so all may load a ton of required files
underneath you.

$ strace -e open ls 2>&1 >/dev/null | grep open | wc -l
36

Jan Engelhardt
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