diff mbox series

[net-next,v4,3/4] net: core: add getsockopt SO_PEERPIDFD

Message ID 20230413133355.350571-4-aleksandr.mikhalitsyn@canonical.com (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series Add SCM_PIDFD and SO_PEERPIDFD | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit fail Errors and warnings before: 832 this patch: 933
netdev/cc_maintainers warning 12 maintainers not CCed: ink@jurassic.park.msu.ru linux-alpha@vger.kernel.org linux-parisc@vger.kernel.org richard.henderson@linaro.org linux-mips@vger.kernel.org James.Bottomley@HansenPartnership.com deller@gmx.de tsbogend@alpha.franken.de martin.lau@kernel.org mattst88@gmail.com sparclinux@vger.kernel.org lnx.erin@gmail.com
netdev/build_clang fail Errors and warnings before: 1162 this patch: 888
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn fail Errors and warnings before: 1389 this patch: 1439
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 94 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Alexander Mikhalitsyn April 13, 2023, 1:33 p.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>
---
v4:
	- return -ESRCH if sk->sk_peer_pid is NULL from getsockopt() syscall
	- return errors from pidfd_prepare() as it is from getsockopt() syscall
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 18, 2023, 1:13 p.m. UTC | #1 
On Thu, Apr 13, 2023 at 03:33:54PM +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>
> ---
> v4:
> 	- return -ESRCH if sk->sk_peer_pid is NULL from getsockopt() syscall
> 	- return errors from pidfd_prepare() as it is from getsockopt() syscall

I see no obvious issues anymore,
Reviewed-by: Christian Brauner <brauner@kernel.org>
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..49531c0dc57f 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);
+
+		if (!peer_pid)
+			return -ESRCH;
+
+		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);
+
+			return -EFAULT;
+		}
+
+		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__)