Messages in this thread | | | Date | Tue, 29 Sep 2015 10:57:43 -0700 | Subject | Re: [PATCH v2] capabilities.7, prctl.2: Document ambient capabilities | From | Kees Cook <> |
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On Tue, Sep 29, 2015 at 10:49 AM, Andy Lutomirski <luto@amacapital.net> wrote: > On Tue, Sep 29, 2015 at 10:47 AM, Kees Cook <keescook@chromium.org> wrote: >> On Mon, Sep 28, 2015 at 6:03 PM, Andy Lutomirski <luto@kernel.org> wrote: >>> Signed-off-by: Andy Lutomirski <luto@kernel.org> >>> --- >>> man2/prctl.2 | 12 ++++++++++++ >>> man7/capabilities.7 | 40 ++++++++++++++++++++++++++++++++++------ >>> 2 files changed, 46 insertions(+), 6 deletions(-) >>> >>> diff --git a/man2/prctl.2 b/man2/prctl.2 >>> index e743a6305969..5bcec391c110 100644 >>> --- a/man2/prctl.2 >>> +++ b/man2/prctl.2 >>> @@ -954,6 +954,18 @@ had been called. >>> For further information on Intel MPX, see the kernel source file >>> .IR Documentation/x86/intel_mpx.txt . >>> .\" >>> +.TP >>> +.BR PR_CAP_AMBIENT " (since Linux 4.2)" >>> +Reads or changes the ambient capability set. If arg2 is PR_CAP_AMBIENT_RAISE, >>> +then the capability specified in arg3 is added to the ambient set. This will >>> +fail, returning EPERM, if the capability is not already both permitted and >>> +inheritable or if the SECBIT_NO_CAP_AMBIENT_RAISE securebit is set. If arg2 >>> +is PR_CAP_AMBIENT_LOWER, then the capability specified in arg3 is removed >>> +from the ambient set. If arg2 is PR_CAP_AMBIENT_IS_SET, then >>> +.BR prctl (2) >>> +will return 1 if the capability in arg3 is in the ambient set and 0 if not. >>> +If arg2 is PR_CAP_AMBIENT_CLEAR_ALL, then all capabilities will >>> +be removed from the ambient set. >> >> In the case of CLEAR_ALL, is arg3 "don't care", or must it be set to 0? > > Must be zero.
Okay, cool. Probably that should be noted here.
-Kees
-- Kees Cook Chrome OS Security
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