On Tue, Sep 15, 2020 at 10:56:18AM +0200, Michael Kerrisk (man-pages) wrote: > Hello Stephen, > > On Mon, 14 Sep 2020 at 20:07, Stephen Smalley > <stephen.smalley.work@xxxxxxxxx> wrote: > > > > SO_PEERSEC was introduced for AF_UNIX stream sockets connected via > > connect(2) in Linux 2.6.2 [1] and later augmented to support AF_UNIX stream > > and datagram sockets created via socketpair(2) in Linux 4.18 [2]. Document > > SO_PEERSEC in the socket.7 and unix.7 man pages following the example > > of the existing SO_PEERCRED descriptions. SO_PEERSEC is also supported > > on AF_INET sockets when using labeled IPSEC or NetLabel but defer > > adding a description of that support to a separate patch. > > > > The module-independent description of the security context returned > > by SO_PEERSEC is from Simon McVittie <smcv@xxxxxxxxxxxxx>. > > Thanks for the patch, The text looks in reasonable shape to me. I'm > just hanging off applying for a bit in case some Reviewed/Acked-by > comes in. > fwiw just as someone who's used this, Reviewed-by: Serge Hallyn <serge@xxxxxxxxxx> Thanks Stephen, thanks Michael. > Cheers, > > Michael > > > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/?id=da6e57a2e6bd7939f610d957afacaf6a131e75ed > > > > [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0b811db2cb2aabc910e53d34ebb95a15997c33e7 > > > > Signed-off-by: Stephen Smalley <stephen.smalley.work@xxxxxxxxx> > > --- > > v2 adds kernel commit info to the description and man page and uses > > the suggested text from Simon McVittie for the description of > > the security context string in a module-neutral way. > > > > man7/socket.7 | 5 +++++ > > man7/unix.7 | 46 ++++++++++++++++++++++++++++++++++++++++++++++ > > 2 files changed, 51 insertions(+) > > > > diff --git a/man7/socket.7 b/man7/socket.7 > > index 21e891791..c3635f95b 100644 > > --- a/man7/socket.7 > > +++ b/man7/socket.7 > > @@ -690,6 +690,11 @@ Return the credentials of the peer process connected to this socket. > > For further details, see > > .BR unix (7). > > .TP > > +.BR SO_PEERSEC " (since Linux 2.6.2)" > > +Return the security context of the peer socket connected to this socket. > > +For further details, see > > +.BR unix (7). > > +.TP > > .B SO_PRIORITY > > Set the protocol-defined priority for all packets to be sent on > > this socket. > > diff --git a/man7/unix.7 b/man7/unix.7 > > index 50828a5bc..298521d4a 100644 > > --- a/man7/unix.7 > > +++ b/man7/unix.7 > > @@ -349,6 +349,52 @@ stream sockets and for > > .B AF_UNIX > > stream and datagram socket pairs created using > > .BR socketpair (2). > > +.TP > > +.B SO_PEERSEC > > +This read-only socket option returns the > > +security context of the peer socket connected to this socket. > > +By default, this will be the same as the security context of > > +the process that created the peer socket unless overridden > > +by the policy or by a process with the required permissions. > > +.IP > > +The argument to > > +.BR getsockopt (2) > > +is a pointer to a > > +buffer of the specified length in bytes > > +into which the security context string will be copied. > > +If the buffer length is less than the length of the security > > +context string, then > > +.BR getsockopt (2) > > +will return the required length > > +via > > +.I optlen > > +and return \-1 and sets > > +.I errno > > +to > > +.BR ERANGE . > > +The caller should allocate at least > > +.BR NAME_MAX > > +bytes for the buffer initially although this is not guaranteed > > +to be sufficient. Resizing the buffer to the returned length > > +and retrying may be necessary. > > +.IP > > +The security context string may include a terminating null character > > +in the returned length, but is not guaranteed to do so: a security > > +context "foo" might be represented as either {'f','o','o'} of length 3 > > +or {'f','o','o','\\0'} of length 4, which are considered to be > > +interchangeable. It is printable, does not contain non-terminating > > +null characters, and is in an unspecified encoding (in particular it > > +is not guaranteed to be ASCII or UTF-8). > > +.IP > > +The use of this option for sockets in the > > +.B AF_UNIX > > +address family > > +is supported since Linux 2.6.2 for connected stream sockets and > > +since Linux 4.18, > > +.\" commit 0b811db2cb2aabc910e53d34ebb95a15997c33e7 > > +also for stream and datagram socket pairs created > > +using > > +.BR socketpair (2). > > .\" > > .SS Autobind feature > > If a > > -- > > 2.25.1 > > > > > -- > Michael Kerrisk > Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ > Linux/UNIX System Programming Training: http://man7.org/training/
