diff mbox series

[net-next,v3,3/4] net: core: add getsockopt SO_PEERPIDFD

Message ID 20230411104231.160837-4-aleksandr.mikhalitsyn@canonical.com
State New
Headers
Series Add SCM_PIDFD and SO_PEERPIDFD |

Commit Message

Aleksandr Mikhalitsyn April 11, 2023, 10:42 a.m. UTC 
  Add SO_PEERPIDFD which allows to get pidfd of peer socket holder pidfd.
This thing is direct analog of SO_PEERCRED which allows to get plain PID.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: David Ahern <dsahern@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: Lennart Poettering <mzxreary@0pointer.de>
Cc: Luca Boccassi <bluca@debian.org>
Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Tested-by: Luca Boccassi <bluca@debian.org>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
---
v3:
	- fixed possible fd leak (thanks to Christian Brauner)
v2:
	According to review comments from Kuniyuki Iwashima and Christian Brauner:
	- use pidfd_create(..) retval as a result
	- whitespace change
---
 arch/alpha/include/uapi/asm/socket.h    |  1 +
 arch/mips/include/uapi/asm/socket.h     |  1 +
 arch/parisc/include/uapi/asm/socket.h   |  1 +
 arch/sparc/include/uapi/asm/socket.h    |  1 +
 include/uapi/asm-generic/socket.h       |  1 +
 net/core/sock.c                         | 33 +++++++++++++++++++++++++
 net/socket.c                            |  7 ++++++
 tools/include/uapi/asm-generic/socket.h |  1 +
 8 files changed, 46 insertions(+)

Comments

Christian Brauner April 11, 2023, 3:57 p.m. UTC | #1 
On Tue, Apr 11, 2023 at 12:42:30PM +0200, Alexander Mikhalitsyn wrote:
> Add SO_PEERPIDFD which allows to get pidfd of peer socket holder pidfd.
> This thing is direct analog of SO_PEERCRED which allows to get plain PID.
> 
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: Leon Romanovsky <leon@kernel.org>
> Cc: David Ahern <dsahern@kernel.org>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Christian Brauner <brauner@kernel.org>
> Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
> Cc: Lennart Poettering <mzxreary@0pointer.de>
> Cc: Luca Boccassi <bluca@debian.org>
> Cc: linux-kernel@vger.kernel.org
> Cc: netdev@vger.kernel.org
> Cc: linux-arch@vger.kernel.org
> Tested-by: Luca Boccassi <bluca@debian.org>
> Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
> ---
> v3:
> 	- fixed possible fd leak (thanks to Christian Brauner)
> v2:
> 	According to review comments from Kuniyuki Iwashima and Christian Brauner:
> 	- use pidfd_create(..) retval as a result
> 	- whitespace change
> ---
>  arch/alpha/include/uapi/asm/socket.h    |  1 +
>  arch/mips/include/uapi/asm/socket.h     |  1 +
>  arch/parisc/include/uapi/asm/socket.h   |  1 +
>  arch/sparc/include/uapi/asm/socket.h    |  1 +
>  include/uapi/asm-generic/socket.h       |  1 +
>  net/core/sock.c                         | 33 +++++++++++++++++++++++++
>  net/socket.c                            |  7 ++++++
>  tools/include/uapi/asm-generic/socket.h |  1 +
>  8 files changed, 46 insertions(+)
> 
> diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
> index ff310613ae64..e94f621903fe 100644
> --- a/arch/alpha/include/uapi/asm/socket.h
> +++ b/arch/alpha/include/uapi/asm/socket.h
> @@ -138,6 +138,7 @@
>  #define SO_RCVMARK		75
>  
>  #define SO_PASSPIDFD		76
> +#define SO_PEERPIDFD		77
>  
>  #if !defined(__KERNEL__)
>  
> diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h
> index 762dcb80e4ec..60ebaed28a4c 100644
> --- a/arch/mips/include/uapi/asm/socket.h
> +++ b/arch/mips/include/uapi/asm/socket.h
> @@ -149,6 +149,7 @@
>  #define SO_RCVMARK		75
>  
>  #define SO_PASSPIDFD		76
> +#define SO_PEERPIDFD		77
>  
>  #if !defined(__KERNEL__)
>  
> diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h
> index df16a3e16d64..be264c2b1a11 100644
> --- a/arch/parisc/include/uapi/asm/socket.h
> +++ b/arch/parisc/include/uapi/asm/socket.h
> @@ -130,6 +130,7 @@
>  #define SO_RCVMARK		0x4049
>  
>  #define SO_PASSPIDFD		0x404A
> +#define SO_PEERPIDFD		0x404B
>  
>  #if !defined(__KERNEL__)
>  
> diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h
> index 6e2847804fea..682da3714686 100644
> --- a/arch/sparc/include/uapi/asm/socket.h
> +++ b/arch/sparc/include/uapi/asm/socket.h
> @@ -131,6 +131,7 @@
>  #define SO_RCVMARK               0x0054
>  
>  #define SO_PASSPIDFD             0x0055
> +#define SO_PEERPIDFD             0x0056
>  
>  #if !defined(__KERNEL__)
>  
> diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
> index b76169fdb80b..8ce8a39a1e5f 100644
> --- a/include/uapi/asm-generic/socket.h
> +++ b/include/uapi/asm-generic/socket.h
> @@ -133,6 +133,7 @@
>  #define SO_RCVMARK		75
>  
>  #define SO_PASSPIDFD		76
> +#define SO_PEERPIDFD		77
>  
>  #if !defined(__KERNEL__)
>  
> diff --git a/net/core/sock.c b/net/core/sock.c
> index 3f974246ba3e..2b040a69e355 100644
> --- a/net/core/sock.c
> +++ b/net/core/sock.c
> @@ -1763,6 +1763,39 @@ int sk_getsockopt(struct sock *sk, int level, int optname,
>  		goto lenout;
>  	}
>  
> +	case SO_PEERPIDFD:
> +	{
> +		struct pid *peer_pid;
> +		struct file *pidfd_file = NULL;
> +		int pidfd;
> +
> +		if (len > sizeof(pidfd))
> +			len = sizeof(pidfd);
> +
> +		spin_lock(&sk->sk_peer_lock);
> +		peer_pid = get_pid(sk->sk_peer_pid);
> +		spin_unlock(&sk->sk_peer_lock);
> +
> +		pidfd = pidfd_prepare(peer_pid, 0, &pidfd_file);
> +
> +		put_pid(peer_pid);

Would be a bit nicer if this would be:

	pidfd = pidfd_prepare(peer_pid, 0, &pidfd_file);
	put_pid(peer_pid);
	if (pidfd < 0)
		return pidfd;
	if (copy_to_sockptr(optval, &pidfd, len) ||
	    copy_to_sockptr(optlen, &len, sizeof(int)))
		return -EFAULT;
	
	fd_install(pidfd, pidfd_file);
	return 0;

Otherwise seems good enough to me.

> +
> +		if (copy_to_sockptr(optval, &pidfd, len) ||
> +		    copy_to_sockptr(optlen, &len, sizeof(int))) {
> +			if (pidfd >= 0) {
> +				put_unused_fd(pidfd);
> +				fput(pidfd_file);
> +			}
> +
> +			return -EFAULT;
> +		}
> +
> +		if (pidfd_file)
> +			fd_install(pidfd, pidfd_file);
> +
> +		return 0;
> +	}
> +
>  	case SO_PEERGROUPS:
>  	{
>  		const struct cred *cred;
> diff --git a/net/socket.c b/net/socket.c
> index 9c1ef11de23f..505b85489354 100644
> --- a/net/socket.c
> +++ b/net/socket.c
> @@ -2248,6 +2248,13 @@ static bool sockopt_installs_fd(int level, int optname)
>  		default:
>  			return false;
>  		}
> +	} else if (level == SOL_SOCKET) {
> +		switch (optname) {
> +		case SO_PEERPIDFD:
> +			return true;
> +		default:
> +			return false;
> +		}
>  	}
>  
>  	return false;
> diff --git a/tools/include/uapi/asm-generic/socket.h b/tools/include/uapi/asm-generic/socket.h
> index fbbc4bf53ee3..54d9c8bf7c55 100644
> --- a/tools/include/uapi/asm-generic/socket.h
> +++ b/tools/include/uapi/asm-generic/socket.h
> @@ -122,6 +122,7 @@
>  #define SO_RCVMARK		75
>  
>  #define SO_PASSPIDFD		76
> +#define SO_PEERPIDFD		77
>  
>  #if !defined(__KERNEL__)
>  
> -- 
> 2.34.1
>
Aleksandr Mikhalitsyn April 11, 2023, 4:02 p.m. UTC | #2 
On Tue, Apr 11, 2023 at 5:57 PM Christian Brauner <brauner@kernel.org> wrote:
>
> On Tue, Apr 11, 2023 at 12:42:30PM +0200, Alexander Mikhalitsyn wrote:
> > Add SO_PEERPIDFD which allows to get pidfd of peer socket holder pidfd.
> > This thing is direct analog of SO_PEERCRED which allows to get plain PID.
> >
> > Cc: "David S. Miller" <davem@davemloft.net>
> > Cc: Eric Dumazet <edumazet@google.com>
> > Cc: Jakub Kicinski <kuba@kernel.org>
> > Cc: Paolo Abeni <pabeni@redhat.com>
> > Cc: Leon Romanovsky <leon@kernel.org>
> > Cc: David Ahern <dsahern@kernel.org>
> > Cc: Arnd Bergmann <arnd@arndb.de>
> > Cc: Kees Cook <keescook@chromium.org>
> > Cc: Christian Brauner <brauner@kernel.org>
> > Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
> > Cc: Lennart Poettering <mzxreary@0pointer.de>
> > Cc: Luca Boccassi <bluca@debian.org>
> > Cc: linux-kernel@vger.kernel.org
> > Cc: netdev@vger.kernel.org
> > Cc: linux-arch@vger.kernel.org
> > Tested-by: Luca Boccassi <bluca@debian.org>
> > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
> > ---
> > v3:
> >       - fixed possible fd leak (thanks to Christian Brauner)
> > v2:
> >       According to review comments from Kuniyuki Iwashima and Christian Brauner:
> >       - use pidfd_create(..) retval as a result
> >       - whitespace change
> > ---
> >  arch/alpha/include/uapi/asm/socket.h    |  1 +
> >  arch/mips/include/uapi/asm/socket.h     |  1 +
> >  arch/parisc/include/uapi/asm/socket.h   |  1 +
> >  arch/sparc/include/uapi/asm/socket.h    |  1 +
> >  include/uapi/asm-generic/socket.h       |  1 +
> >  net/core/sock.c                         | 33 +++++++++++++++++++++++++
> >  net/socket.c                            |  7 ++++++
> >  tools/include/uapi/asm-generic/socket.h |  1 +
> >  8 files changed, 46 insertions(+)
> >
> > diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
> > index ff310613ae64..e94f621903fe 100644
> > --- a/arch/alpha/include/uapi/asm/socket.h
> > +++ b/arch/alpha/include/uapi/asm/socket.h
> > @@ -138,6 +138,7 @@
> >  #define SO_RCVMARK           75
> >
> >  #define SO_PASSPIDFD         76
> > +#define SO_PEERPIDFD         77
> >
> >  #if !defined(__KERNEL__)
> >
> > diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h
> > index 762dcb80e4ec..60ebaed28a4c 100644
> > --- a/arch/mips/include/uapi/asm/socket.h
> > +++ b/arch/mips/include/uapi/asm/socket.h
> > @@ -149,6 +149,7 @@
> >  #define SO_RCVMARK           75
> >
> >  #define SO_PASSPIDFD         76
> > +#define SO_PEERPIDFD         77
> >
> >  #if !defined(__KERNEL__)
> >
> > diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h
> > index df16a3e16d64..be264c2b1a11 100644
> > --- a/arch/parisc/include/uapi/asm/socket.h
> > +++ b/arch/parisc/include/uapi/asm/socket.h
> > @@ -130,6 +130,7 @@
> >  #define SO_RCVMARK           0x4049
> >
> >  #define SO_PASSPIDFD         0x404A
> > +#define SO_PEERPIDFD         0x404B
> >
> >  #if !defined(__KERNEL__)
> >
> > diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h
> > index 6e2847804fea..682da3714686 100644
> > --- a/arch/sparc/include/uapi/asm/socket.h
> > +++ b/arch/sparc/include/uapi/asm/socket.h
> > @@ -131,6 +131,7 @@
> >  #define SO_RCVMARK               0x0054
> >
> >  #define SO_PASSPIDFD             0x0055
> > +#define SO_PEERPIDFD             0x0056
> >
> >  #if !defined(__KERNEL__)
> >
> > diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
> > index b76169fdb80b..8ce8a39a1e5f 100644
> > --- a/include/uapi/asm-generic/socket.h
> > +++ b/include/uapi/asm-generic/socket.h
> > @@ -133,6 +133,7 @@
> >  #define SO_RCVMARK           75
> >
> >  #define SO_PASSPIDFD         76
> > +#define SO_PEERPIDFD         77
> >
> >  #if !defined(__KERNEL__)
> >
> > diff --git a/net/core/sock.c b/net/core/sock.c
> > index 3f974246ba3e..2b040a69e355 100644
> > --- a/net/core/sock.c
> > +++ b/net/core/sock.c
> > @@ -1763,6 +1763,39 @@ int sk_getsockopt(struct sock *sk, int level, int optname,
> >               goto lenout;
> >       }
> >
> > +     case SO_PEERPIDFD:
> > +     {
> > +             struct pid *peer_pid;
> > +             struct file *pidfd_file = NULL;
> > +             int pidfd;
> > +
> > +             if (len > sizeof(pidfd))
> > +                     len = sizeof(pidfd);
> > +
> > +             spin_lock(&sk->sk_peer_lock);
> > +             peer_pid = get_pid(sk->sk_peer_pid);
> > +             spin_unlock(&sk->sk_peer_lock);
> > +
> > +             pidfd = pidfd_prepare(peer_pid, 0, &pidfd_file);
> > +
> > +             put_pid(peer_pid);
>
> Would be a bit nicer if this would be:
>
>         pidfd = pidfd_prepare(peer_pid, 0, &pidfd_file);
>         put_pid(peer_pid);
>         if (pidfd < 0)
>                 return pidfd;
>         if (copy_to_sockptr(optval, &pidfd, len) ||
>             copy_to_sockptr(optlen, &len, sizeof(int)))
{
                            put_unused_fd(pidfd);
                            fput(pidfd_file);

are still needed there, right?

>                 return -EFAULT;
}

>
>         fd_install(pidfd, pidfd_file);
>         return 0;
>
> Otherwise seems good enough to me.

Will do.

>
> > +
> > +             if (copy_to_sockptr(optval, &pidfd, len) ||
> > +                 copy_to_sockptr(optlen, &len, sizeof(int))) {
> > +                     if (pidfd >= 0) {
> > +                             put_unused_fd(pidfd);
> > +                             fput(pidfd_file);
> > +                     }
> > +
> > +                     return -EFAULT;
> > +             }
> > +
> > +             if (pidfd_file)
> > +                     fd_install(pidfd, pidfd_file);
> > +
> > +             return 0;
> > +     }
> > +
> >       case SO_PEERGROUPS:
> >       {
> >               const struct cred *cred;
> > diff --git a/net/socket.c b/net/socket.c
> > index 9c1ef11de23f..505b85489354 100644
> > --- a/net/socket.c
> > +++ b/net/socket.c
> > @@ -2248,6 +2248,13 @@ static bool sockopt_installs_fd(int level, int optname)
> >               default:
> >                       return false;
> >               }
> > +     } else if (level == SOL_SOCKET) {
> > +             switch (optname) {
> > +             case SO_PEERPIDFD:
> > +                     return true;
> > +             default:
> > +                     return false;
> > +             }
> >       }
> >
> >       return false;
> > diff --git a/tools/include/uapi/asm-generic/socket.h b/tools/include/uapi/asm-generic/socket.h
> > index fbbc4bf53ee3..54d9c8bf7c55 100644
> > --- a/tools/include/uapi/asm-generic/socket.h
> > +++ b/tools/include/uapi/asm-generic/socket.h
> > @@ -122,6 +122,7 @@
> >  #define SO_RCVMARK           75
> >
> >  #define SO_PASSPIDFD         76
> > +#define SO_PEERPIDFD         77
> >
> >  #if !defined(__KERNEL__)
> >
> > --
> > 2.34.1
> >
diff mbox series

Patch

diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
index ff310613ae64..e94f621903fe 100644
--- a/arch/alpha/include/uapi/asm/socket.h
+++ b/arch/alpha/include/uapi/asm/socket.h
@@ -138,6 +138,7 @@ 
 #define SO_RCVMARK		75
 
 #define SO_PASSPIDFD		76
+#define SO_PEERPIDFD		77
 
 #if !defined(__KERNEL__)
 
diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h
index 762dcb80e4ec..60ebaed28a4c 100644
--- a/arch/mips/include/uapi/asm/socket.h
+++ b/arch/mips/include/uapi/asm/socket.h
@@ -149,6 +149,7 @@ 
 #define SO_RCVMARK		75
 
 #define SO_PASSPIDFD		76
+#define SO_PEERPIDFD		77
 
 #if !defined(__KERNEL__)
 
diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h
index df16a3e16d64..be264c2b1a11 100644
--- a/arch/parisc/include/uapi/asm/socket.h
+++ b/arch/parisc/include/uapi/asm/socket.h
@@ -130,6 +130,7 @@ 
 #define SO_RCVMARK		0x4049
 
 #define SO_PASSPIDFD		0x404A
+#define SO_PEERPIDFD		0x404B
 
 #if !defined(__KERNEL__)
 
diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h
index 6e2847804fea..682da3714686 100644
--- a/arch/sparc/include/uapi/asm/socket.h
+++ b/arch/sparc/include/uapi/asm/socket.h
@@ -131,6 +131,7 @@ 
 #define SO_RCVMARK               0x0054
 
 #define SO_PASSPIDFD             0x0055
+#define SO_PEERPIDFD             0x0056
 
 #if !defined(__KERNEL__)
 
diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
index b76169fdb80b..8ce8a39a1e5f 100644
--- a/include/uapi/asm-generic/socket.h
+++ b/include/uapi/asm-generic/socket.h
@@ -133,6 +133,7 @@ 
 #define SO_RCVMARK		75
 
 #define SO_PASSPIDFD		76
+#define SO_PEERPIDFD		77
 
 #if !defined(__KERNEL__)
 
diff --git a/net/core/sock.c b/net/core/sock.c
index 3f974246ba3e..2b040a69e355 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1763,6 +1763,39 @@  int sk_getsockopt(struct sock *sk, int level, int optname,
 		goto lenout;
 	}
 
+	case SO_PEERPIDFD:
+	{
+		struct pid *peer_pid;
+		struct file *pidfd_file = NULL;
+		int pidfd;
+
+		if (len > sizeof(pidfd))
+			len = sizeof(pidfd);
+
+		spin_lock(&sk->sk_peer_lock);
+		peer_pid = get_pid(sk->sk_peer_pid);
+		spin_unlock(&sk->sk_peer_lock);
+
+		pidfd = pidfd_prepare(peer_pid, 0, &pidfd_file);
+
+		put_pid(peer_pid);
+
+		if (copy_to_sockptr(optval, &pidfd, len) ||
+		    copy_to_sockptr(optlen, &len, sizeof(int))) {
+			if (pidfd >= 0) {
+				put_unused_fd(pidfd);
+				fput(pidfd_file);
+			}
+
+			return -EFAULT;
+		}
+
+		if (pidfd_file)
+			fd_install(pidfd, pidfd_file);
+
+		return 0;
+	}
+
 	case SO_PEERGROUPS:
 	{
 		const struct cred *cred;
diff --git a/net/socket.c b/net/socket.c
index 9c1ef11de23f..505b85489354 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2248,6 +2248,13 @@  static bool sockopt_installs_fd(int level, int optname)
 		default:
 			return false;
 		}
+	} else if (level == SOL_SOCKET) {
+		switch (optname) {
+		case SO_PEERPIDFD:
+			return true;
+		default:
+			return false;
+		}
 	}
 
 	return false;
diff --git a/tools/include/uapi/asm-generic/socket.h b/tools/include/uapi/asm-generic/socket.h
index fbbc4bf53ee3..54d9c8bf7c55 100644
--- a/tools/include/uapi/asm-generic/socket.h
+++ b/tools/include/uapi/asm-generic/socket.h
@@ -122,6 +122,7 @@ 
 #define SO_RCVMARK		75
 
 #define SO_PASSPIDFD		76
+#define SO_PEERPIDFD		77
 
 #if !defined(__KERNEL__)