Hi Andy, Not that this has hit mainline, would you be willing to refresh this man-pages patch? Thanks, Michael On 15 May 2015 at 08:43, Andy Lutomirski <luto@xxxxxxxxxx> wrote: > Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx> > --- > > There was no v1. I'm calling this v2 to keep it in sync with the kernel > patch versioning. > > man2/prctl.2 | 10 ++++++++++ > man7/capabilities.7 | 32 ++++++++++++++++++++++++++------ > 2 files changed, 36 insertions(+), 6 deletions(-) > > diff --git a/man2/prctl.2 b/man2/prctl.2 > index b352f6283624..5861e3aefe9a 100644 > --- a/man2/prctl.2 > +++ b/man2/prctl.2 > @@ -949,6 +949,16 @@ 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_GET, then > +.BR prctl (2) > +will return 1 if the capability in arg3 is in the ambient set and 0 if not. > .SH RETURN VALUE > On success, > .BR PR_GET_DUMPABLE , > diff --git a/man7/capabilities.7 b/man7/capabilities.7 > index d75ec65de05b..dae62f0be3b7 100644 > --- a/man7/capabilities.7 > +++ b/man7/capabilities.7 > @@ -697,13 +697,26 @@ a program whose associated file capabilities grant that capability). > .IR Inheritable : > This is a set of capabilities preserved across an > .BR execve (2). > -It provides a mechanism for a process to assign capabilities > -to the permitted set of the new program during an > -.BR execve (2). > +Inheritable capabilities remain inheritable when executing any program, > +and inheritable capabilities are added to the permitted set when executing > +a program that has the corresponding bits set in the file inheritable set. > +When executing programs without file capabilities, ambient capabilities > .TP > .IR Effective : > This is the set of capabilities used by the kernel to > perform permission checks for the thread. > +.TP > +.IR Ambient " (since Linux 4.2) :" > +This is a set of capabilities that are preserved across an > +.BR execve (2) > +of a program that does not have file capabilities. The ambient capability > +set obeys the invariant that no capability can ever be ambient if it is > +not both permitted and inheritable. Ambient capabilities are, with some > +exceptions, preserved in the permitted set and added to the effective > +set when > +.BR execve (2) > +is called. The ambient capability set is modified using > +.BR prctl (2). > .PP > A child created via > .BR fork (2) > @@ -785,10 +798,12 @@ the process using the following algorithm: > .in +4n > .nf > > +P'(ambient) = (file has capabilities or is setuid or setgid) ? 0 : P(ambient) > + > P'(permitted) = (P(inheritable) & F(inheritable)) | > - (F(permitted) & cap_bset) > + (F(permitted) & cap_bset) | P'(ambient) > > -P'(effective) = F(effective) ? P'(permitted) : 0 > +P'(effective) = F(effective) ? P'(permitted) : P'(ambient) > > P'(inheritable) = P(inheritable) [i.e., unchanged] > > @@ -1071,6 +1086,10 @@ an effective or real UID of 0 calls > .BR execve (2). > (See the subsection > .IR "Capabilities and execution of programs by root" .) > +.TP > +.B SECBIT_NO_CAP_AMBIENT_RAISE > +Setting this flag disallows > +.BR PR_CAP_AMBIENT_RAISE . > .PP > Each of the above "base" flags has a companion "locked" flag. > Setting any of the "locked" flags is irreversible, > @@ -1079,8 +1098,9 @@ corresponding "base" flag. > The locked flags are: > .BR SECBIT_KEEP_CAPS_LOCKED , > .BR SECBIT_NO_SETUID_FIXUP_LOCKED , > +.BR SECBIT_NOROOT_LOCKED , > and > -.BR SECBIT_NOROOT_LOCKED . > +.BR SECBIT_NO_CAP_AMBIENT_RAISE . > .PP > The > .I securebits > -- > 2.1.0 > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
