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@xxxxxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
Cc: Leon Romanovsky <leon@xxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Cc: Lennart Poettering <mzxreary@xxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: netdev@xxxxxxxxxxxxxxx
Cc: linux-arch@xxxxxxxxxxxxxxx
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx>
---
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 | 21 +++++++++++++++++++++
tools/include/uapi/asm-generic/socket.h | 1 +
7 files changed, 27 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..85c269ca9d8a 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1763,6 +1763,27 @@ int sk_getsockopt(struct sock *sk, int level, int optname,
goto lenout;
}
+ case SO_PEERPIDFD:
+ {
+ struct pid *peer_pid;
+ 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_create(peer_pid, 0);
+
+ put_pid(peer_pid);
+
+ if (copy_to_sockptr(optval, &pidfd, len))
+ return -EFAULT;
+ goto lenout;
+ }
+
case SO_PEERGROUPS:
{
const struct cred *cred;
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
