diff mbox series

[v4,1/3] qio: add support for SO_PEERCRED for socket channel

Message ID 20240318151216.32833-2-aharivel@redhat.com (mailing list archive)
State New, archived
Headers show
Series Add support for the RAPL MSRs series | expand

Commit Message

Anthony Harivel March 18, 2024, 3:12 p.m. UTC
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 <sys/socket.h> 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 <aharivel@redhat.com>
---
 include/io/channel.h | 21 +++++++++++++++++++++
 io/channel-socket.c  | 24 ++++++++++++++++++++++++
 io/channel.c         | 12 ++++++++++++
 3 files changed, 57 insertions(+)

Comments

Daniel P. Berrangé March 20, 2024, 5:18 p.m. UTC | #1
On Mon, Mar 18, 2024 at 04:12:14PM +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 <sys/socket.h> 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 <aharivel@redhat.com>
> ---
>  include/io/channel.h | 21 +++++++++++++++++++++
>  io/channel-socket.c  | 24 ++++++++++++++++++++++++
>  io/channel.c         | 12 ++++++++++++
>  3 files changed, 57 insertions(+)
> 
> diff --git a/include/io/channel.h b/include/io/channel.h
> index 7986c49c713a..01ad7bd7e430 100644
> --- a/include/io/channel.h
> +++ b/include/io/channel.h
> @@ -160,6 +160,9 @@ struct QIOChannelClass {
>                                    void *opaque);
>      int (*io_flush)(QIOChannel *ioc,
>                      Error **errp);
> +    void (*io_peerpid)(QIOChannel *ioc,
> +                       unsigned int *pid,
> +                       Error **errp);
>  };
>  
>  /* General I/O handling functions */
> @@ -981,4 +984,22 @@ 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 an error with pid -1 for the non-Linux OS.
> + *
> + */
> +void qio_channel_get_peerpid(QIOChannel *ioc,
> +                             unsigned int *pid,
> +                             Error **errp);
> +
>  #endif /* QIO_CHANNEL_H */
> diff --git a/io/channel-socket.c b/io/channel-socket.c
> index 3a899b060858..fcff92ecc151 100644
> --- a/io/channel-socket.c
> +++ b/io/channel-socket.c
> @@ -841,6 +841,29 @@ 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) {

Set '*pid = -1'

> +        error_setg_errno(&err, errno, "Unable to get peer credentials");
> +        error_propagate(errp, err);

and 'return;' here, since accessing 'cred.pid' below
is undefined behaviour if getsockopt failed.

> +    }
> +    *pid = (unsigned int)cred.pid;
> +#else
> +    error_setg(errp, "Unsupported feature");
> +    *pid = -1;
> +#endif
> +}
>  
>  static int
>  qio_channel_socket_close(QIOChannel *ioc,
> @@ -938,6 +961,7 @@ 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 a1f12f8e9096..777989bc9a81 100644
> --- a/io/channel.c
> +++ b/io/channel.c
> @@ -548,6 +548,18 @@ 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,
> -- 
> 2.44.0
> 

With regards,
Daniel
diff mbox series

Patch

diff --git a/include/io/channel.h b/include/io/channel.h
index 7986c49c713a..01ad7bd7e430 100644
--- a/include/io/channel.h
+++ b/include/io/channel.h
@@ -160,6 +160,9 @@  struct QIOChannelClass {
                                   void *opaque);
     int (*io_flush)(QIOChannel *ioc,
                     Error **errp);
+    void (*io_peerpid)(QIOChannel *ioc,
+                       unsigned int *pid,
+                       Error **errp);
 };
 
 /* General I/O handling functions */
@@ -981,4 +984,22 @@  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 an error with pid -1 for the non-Linux OS.
+ *
+ */
+void qio_channel_get_peerpid(QIOChannel *ioc,
+                             unsigned int *pid,
+                             Error **errp);
+
 #endif /* QIO_CHANNEL_H */
diff --git a/io/channel-socket.c b/io/channel-socket.c
index 3a899b060858..fcff92ecc151 100644
--- a/io/channel-socket.c
+++ b/io/channel-socket.c
@@ -841,6 +841,29 @@  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
+    error_setg(errp, "Unsupported feature");
+    *pid = -1;
+#endif
+}
 
 static int
 qio_channel_socket_close(QIOChannel *ioc,
@@ -938,6 +961,7 @@  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 a1f12f8e9096..777989bc9a81 100644
--- a/io/channel.c
+++ b/io/channel.c
@@ -548,6 +548,18 @@  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,