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Thu, 25 Jan 2024 16:38:01 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.95]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 939033C2E; Thu, 25 Jan 2024 16:38:00 +0000 (UTC) Date: Thu, 25 Jan 2024 16:37:58 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Anthony Harivel Cc: pbonzini@redhat.com, mtosatti@redhat.com, qemu-devel@nongnu.org, vchundur@redhat.com Subject: Re: [PATCH v3 1/3] qio: add support for SO_PEERCRED for socket channel Message-ID: References: <20240125072214.318382-1-aharivel@redhat.com> <20240125072214.318382-2-aharivel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240125072214.318382-2-aharivel@redhat.com> User-Agent: Mutt/2.2.10 (2023-03-25) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -35 X-Spam_score: -3.6 X-Spam_bar: --- X-Spam_report: (-3.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.5, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Thu, Jan 25, 2024 at 08:22:12AM +0100, Anthony Harivel wrote: > The function qio_channel_get_peercred() returns a pointer to the > credentials of the peer process connected to this socket. > > This credentials structure is defined in as follows: > > struct ucred { > pid_t pid; /* Process ID of the sending process */ > uid_t uid; /* User ID of the sending process */ > gid_t gid; /* Group ID of the sending process */ > }; > > The use of this function is possible only for connected AF_UNIX stream > sockets and for AF_UNIX stream and datagram socket pairs. > > On platform other than Linux, the function return 0. > > Signed-off-by: Anthony Harivel > --- > include/io/channel.h | 21 +++++++++++++++++++++ > io/channel-socket.c | 23 +++++++++++++++++++++++ > io/channel.c | 12 ++++++++++++ > 3 files changed, 56 insertions(+) > > diff --git a/include/io/channel.h b/include/io/channel.h > index 5f9dbaab65b0..0413435ce011 100644 > --- a/include/io/channel.h > +++ b/include/io/channel.h > @@ -149,6 +149,9 @@ struct QIOChannelClass { > void *opaque); > int (*io_flush)(QIOChannel *ioc, > Error **errp); > + void (*io_peerpid)(QIOChannel *ioc, > + unsigned int *pid, > + Error **errp); Idented 1 space too many > }; > > /* General I/O handling functions */ > @@ -898,4 +901,22 @@ int coroutine_mixed_fn qio_channel_writev_full_all(QIOChannel *ioc, > int qio_channel_flush(QIOChannel *ioc, > Error **errp); > > +/** > + * qio_channel_get_peercred: > + * @ioc: the channel object > + * @pid: pointer to pid > + * @errp: pointer to a NULL-initialized error object > + * > + * Returns the pid of the peer process connected to this socket. > + * > + * The use of this function is possible only for connected > + * AF_UNIX stream sockets and for AF_UNIX stream and datagram > + * socket pairs on Linux. > + * Return 0 for the non-Linux OS. Update to say this returns an error for other platforms > + * > + */ > +void qio_channel_get_peerpid(QIOChannel *ioc, > + unsigned int *pid, > + Error **errp); Idented 1 space too many > + > #endif /* QIO_CHANNEL_H */ > diff --git a/io/channel-socket.c b/io/channel-socket.c > index 3a899b060858..e6a73592650c 100644 > --- a/io/channel-socket.c > +++ b/io/channel-socket.c > @@ -841,6 +841,28 @@ qio_channel_socket_set_cork(QIOChannel *ioc, > socket_set_cork(sioc->fd, v); > } > > +static void > +qio_channel_socket_get_peerpid(QIOChannel *ioc, > + unsigned int *pid, > + Error **errp) > +{ > +#ifdef CONFIG_LINUX > + QIOChannelSocket *sioc = QIO_CHANNEL_SOCKET(ioc); > + Error *err = NULL; > + socklen_t len = sizeof(struct ucred); > + > + struct ucred cred; > + if (getsockopt(sioc->fd, > + SOL_SOCKET, SO_PEERCRED, > + &cred, &len) == -1) { > + error_setg_errno(&err, errno, "Unable to get peer credentials"); > + error_propagate(errp, err); > + } > + *pid = (unsigned int)cred.pid; > +#else > + *pid = 0; Defaulting 'pid' to 0 is potentially unsafe, because to a caller it now appears that the remote party is 'root' and thus implied to be a privileged account. We should 'error_setg' for any platform we don't have an impl on, so the caller will see a fail for any usage. > +#endif > +} > > static int > qio_channel_socket_close(QIOChannel *ioc, > @@ -938,6 +960,7 @@ static void qio_channel_socket_class_init(ObjectClass *klass, > #ifdef QEMU_MSG_ZEROCOPY > ioc_klass->io_flush = qio_channel_socket_flush; > #endif > + ioc_klass->io_peerpid = qio_channel_socket_get_peerpid; > } > > static const TypeInfo qio_channel_socket_info = { > diff --git a/io/channel.c b/io/channel.c > index 86c5834510ff..a5646650cf72 100644 > --- a/io/channel.c > +++ b/io/channel.c > @@ -490,6 +490,18 @@ void qio_channel_set_cork(QIOChannel *ioc, > } > } > > +void qio_channel_get_peerpid(QIOChannel *ioc, > + unsigned int *pid, > + Error **errp) > +{ > + QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc); > + > + if (!klass->io_peerpid) { > + error_setg(errp, "Channel does not support peer pid"); > + return; > + } > + klass->io_peerpid(ioc, pid, errp); > +} > > off_t qio_channel_io_seek(QIOChannel *ioc, > off_t offset, With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|