Add SO_PEERCGROUPID which allows to get cgroup_id
for a socket.
We already have analogical interfaces to retrieve this
information:
- inet_diag: INET_DIAG_CGROUP_ID
- eBPF: bpf_sk_cgroup_id
Having getsockopt() interface makes sense for many
applications, because using eBPF is not always an option,
while inet_diag has obvious complexety and performance drawbacks
if we only want to get this specific info for one specific socket.
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: netdev@xxxxxxxxxxxxxxx
Cc: cgroups@xxxxxxxxxxxxxxx
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
Cc: Willem de Bruijn <willemb@xxxxxxxxxx>
Cc: Leon Romanovsky <leon@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Cc: Lennart Poettering <mzxreary@xxxxxxxxxxx>
Cc: Luca Boccassi <bluca@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: "Michal Koutný" <mkoutny@xxxxxxxx>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx>
---
arch/alpha/include/uapi/asm/socket.h | 2 +
arch/mips/include/uapi/asm/socket.h | 2 +
arch/parisc/include/uapi/asm/socket.h | 2 +
arch/sparc/include/uapi/asm/socket.h | 2 +
include/uapi/asm-generic/socket.h | 2 +
net/core/sock.c | 17 +++++++
net/unix/af_unix.c | 63 +++++++++++++++++++++++++
tools/include/uapi/asm-generic/socket.h | 2 +
8 files changed, 92 insertions(+)
diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
index 3df5f2dd4c0f..58ce457b2c09 100644
--- a/arch/alpha/include/uapi/asm/socket.h
+++ b/arch/alpha/include/uapi/asm/socket.h
@@ -150,6 +150,8 @@
#define SO_RCVPRIORITY 82
+#define SO_PEERCGROUPID 83
+
#if !defined(__KERNEL__)
#if __BITS_PER_LONG == 64
diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h
index 22fa8f19924a..823fa67f7d79 100644
--- a/arch/mips/include/uapi/asm/socket.h
+++ b/arch/mips/include/uapi/asm/socket.h
@@ -161,6 +161,8 @@
#define SO_RCVPRIORITY 82
+#define SO_PEERCGROUPID 83
+
#if !defined(__KERNEL__)
#if __BITS_PER_LONG == 64
diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h
index aa9cd4b951fe..1ee2e858d177 100644
--- a/arch/parisc/include/uapi/asm/socket.h
+++ b/arch/parisc/include/uapi/asm/socket.h
@@ -142,6 +142,8 @@
#define SO_RCVPRIORITY 0x404D
+#define SO_PEERCGROUPID 0x404E
+
#if !defined(__KERNEL__)
#if __BITS_PER_LONG == 64
diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h
index 5b464a568664..2fe7d0c48a63 100644
--- a/arch/sparc/include/uapi/asm/socket.h
+++ b/arch/sparc/include/uapi/asm/socket.h
@@ -143,6 +143,8 @@
#define SO_RCVPRIORITY 0x005b
+#define SO_PEERCGROUPID 0x005c
+
#if !defined(__KERNEL__)
diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
index aa5016ff3d91..903904bb537c 100644
--- a/include/uapi/asm-generic/socket.h
+++ b/include/uapi/asm-generic/socket.h
@@ -145,6 +145,8 @@
#define SO_RCVPRIORITY 82
+#define SO_PEERCGROUPID 83
+
#if !defined(__KERNEL__)
#if __BITS_PER_LONG == 64 || (defined(__x86_64__) && defined(__ILP32__))
diff --git a/net/core/sock.c b/net/core/sock.c
index a0598518ce89..6dc0b1a8367b 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1946,6 +1946,23 @@ int sk_getsockopt(struct sock *sk, int level, int optname,
goto lenout;
}
+#ifdef CONFIG_SOCK_CGROUP_DATA
+ case SO_PEERCGROUPID:
+ {
+ const struct proto_ops *ops;
+
+ if (sk->sk_family != AF_UNIX)
+ return -EOPNOTSUPP;
+
+ ops = READ_ONCE(sock->ops);
+ if (!ops->getsockopt)
+ return -EOPNOTSUPP;
+
+ return ops->getsockopt(sock, SOL_SOCKET, optname, optval.user,
+ optlen.user);
+ }
+#endif
+
/* Dubious BSD thing... Probably nobody even uses it, but
* the UNIX standard wants it for whatever reason... -DaveM
*/
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 2b2c0036efc9..3455f38f033d 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -901,6 +901,66 @@ static void unix_show_fdinfo(struct seq_file *m, struct socket *sock)
#define unix_show_fdinfo NULL
#endif
+static int unix_getsockopt(struct socket *sock, int level, int optname,
+ char __user *optval, int __user *optlen)
+{
+ struct sock *sk = sock->sk;
+
+ union {
+ int val;
+ u64 val64;
+ } v;
+
+ int lv = sizeof(int);
+ int len;
+
+ if (level != SOL_SOCKET)
+ return -ENOPROTOOPT;
+
+ if (get_user(len, optlen))
+ return -EFAULT;
+
+ if (len < 0)
+ return -EINVAL;
+
+ memset(&v, 0, sizeof(v));
+
+ switch (optname) {
+#ifdef CONFIG_SOCK_CGROUP_DATA
+ case SO_PEERCGROUPID:
+ {
+ struct sock *peer;
+ u64 peer_cgroup_id = 0;
+
+ lv = sizeof(u64);
+ if (len < lv)
+ return -EINVAL;
+
+ peer = unix_peer_get(sk);
+ if (!peer)
+ return -ENODATA;
+
+ peer_cgroup_id = cgroup_id(sock_cgroup_ptr(&peer->sk_cgrp_data));
+ sock_put(peer);
+
+ v.val64 = peer_cgroup_id;
+ break;
+ }
+#endif
+ default:
+ return -ENOPROTOOPT;
+ }
+
+ if (len > lv)
+ len = lv;
+ if (copy_to_user(optval, &v, len))
+ return -EFAULT;
+ if (put_user(len, optlen))
+ return -EFAULT;
+
+ return 0;
+}
+
static const struct proto_ops unix_stream_ops = {
.family = PF_UNIX,
.owner = THIS_MODULE,
@@ -910,6 +970,7 @@ static const struct proto_ops unix_stream_ops = {
.socketpair = unix_socketpair,
.accept = unix_accept,
.getname = unix_getname,
+ .getsockopt = unix_getsockopt,
.poll = unix_poll,
.ioctl = unix_ioctl,
#ifdef CONFIG_COMPAT
@@ -935,6 +996,7 @@ static const struct proto_ops unix_dgram_ops = {
.socketpair = unix_socketpair,
.accept = sock_no_accept,
.getname = unix_getname,
+ .getsockopt = unix_getsockopt,
.poll = unix_dgram_poll,
.ioctl = unix_ioctl,
#ifdef CONFIG_COMPAT
@@ -959,6 +1021,7 @@ static const struct proto_ops unix_seqpacket_ops = {
.socketpair = unix_socketpair,
.accept = unix_accept,
.getname = unix_getname,
+ .getsockopt = unix_getsockopt,
.poll = unix_dgram_poll,
.ioctl = unix_ioctl,
#ifdef CONFIG_COMPAT
diff --git a/tools/include/uapi/asm-generic/socket.h b/tools/include/uapi/asm-generic/socket.h
index aa5016ff3d91..903904bb537c 100644
--- a/tools/include/uapi/asm-generic/socket.h
+++ b/tools/include/uapi/asm-generic/socket.h
@@ -145,6 +145,8 @@
#define SO_RCVPRIORITY 82
+#define SO_PEERCGROUPID 83
+
#if !defined(__KERNEL__)
#if __BITS_PER_LONG == 64 || (defined(__x86_64__) && defined(__ILP32__))
--
2.43.0
