Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
pull-request: bpf-next 2024-01-05

We've added 40 non-merge commits during the last 2 day(s) which contain
a total of 73 files changed, 1526 insertions(+), 951 deletions(-).

The main changes are:

1) Fix a memory leak when streaming AF_UNIX sockets were inserted
   into multiple sockmap slots/maps, from John Fastabend.

2) Fix gotol in s390 BPF JIT with large offsets, from Ilya Leoshkevich.

3) Fix reattachment branch in bpf_tracing_prog_attach() and reject
   the request if there is no valid attach_btf, from Jiri Olsa.

4) Remove deprecated bpfilter kernel leftovers given the project
   is developed in user space (https://github.com/facebook/bpfilter),
   from Quentin Deslandes.

5) Relax tracing BPF program recursive attach rules given right now
   it is not possible to create tracing program call cycles,
   from Dmitrii Dolgov.

6) Fix excessive memory consumption for the bpf_global_percpu_ma
   for systems with a large number of CPUs, from Yonghong Song.

7) Small x86 BPF JIT cleanup to reuse emit_nops instead of open-coding
   memcpy of x86_nops, from Leon Hwang.

8) Follow-up for libbpf to support __arg_ctx global function argument tag
   semantics to complement the merged kernel side, from Andrii Nakryiko.

9) Introduce "volatile compare" macros for BPF selftests in order
   to make the latter more robust against compiler optimization,
   from Alexei Starovoitov.

10) Small simplification in verifier's size checking of helper accesses
    along with additional selftests, from Andrei Matei.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (40 commits)
  selftests/bpf: Test re-attachment fix for bpf_tracing_prog_attach
  bpf: Fix re-attachment branch in bpf_tracing_prog_attach
  selftests/bpf: Add test for recursive attachment of tracing progs
  bpf: Relax tracing prog recursive attach rules
  bpf, x86: Use emit_nops to replace memcpy x86_nops
  selftests/bpf: Test gotol with large offsets
  selftests/bpf: Double the size of test_loader log
  s390/bpf: Fix gotol with large offsets
  bpfilter: remove bpfilter
  bpf: Remove unnecessary cpu == 0 check in memalloc
  selftests/bpf: add __arg_ctx BTF rewrite test
  selftests/bpf: add arg:ctx cases to test_global_funcs tests
  libbpf: implement __arg_ctx fallback logic
  libbpf: move BTF loading step after relocation step
  libbpf: move exception callbacks assignment logic into relocation step
  libbpf: use stable map placeholder FDs
  libbpf: don't rely on map->fd as an indicator of map being created
  libbpf: use explicit map reuse flag to skip map creation steps
  libbpf: make uniform use of btf__fd() accessor inside libbpf
  selftests/bpf: Add a selftest with > 512-byte percpu allocation size
  ...
====================

Link: https://lore.kernel.org/r/20240105170105.21070-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

14 files changed, 18 insertions, 362 deletions

diff --git a/net/Kconfig b/net/Kconfig
index 3ec6bc98fa05..4adc47d0c9c2 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -233,8 +233,6 @@ source "net/bridge/netfilter/Kconfig"
 
 endif
 
-source "net/bpfilter/Kconfig"
-
 source "net/dccp/Kconfig"
 source "net/sctp/Kconfig"
 source "net/rds/Kconfig"
diff --git a/net/Makefile b/net/Makefile
index 4c4dc535453d..b06b5539e7a6 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -19,7 +19,6 @@ obj-$(CONFIG_TLS)		+= tls/
 obj-$(CONFIG_XFRM)		+= xfrm/
 obj-$(CONFIG_UNIX_SCM)		+= unix/
 obj-y				+= ipv6/
-obj-$(CONFIG_BPFILTER)		+= bpfilter/
 obj-$(CONFIG_PACKET)		+= packet/
 obj-$(CONFIG_NET_KEY)		+= key/
 obj-$(CONFIG_BRIDGE)		+= bridge/
diff --git a/net/bpfilter/.gitignore b/net/bpfilter/.gitignore
deleted file mode 100644
index f34e85ee8204..000000000000
--- a/net/bpfilter/.gitignore
+++ /dev/null
@@ -1,2 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0-only
-bpfilter_umh
diff --git a/net/bpfilter/Kconfig b/net/bpfilter/Kconfig
deleted file mode 100644
index 3d4a21462458..000000000000
--- a/net/bpfilter/Kconfig
+++ /dev/null
@@ -1,23 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0-only
-menuconfig BPFILTER
-	bool "BPF based packet filtering framework (BPFILTER)"
-	depends on BPF && INET
-	select USERMODE_DRIVER
-	help
-	  This builds experimental bpfilter framework that is aiming to
-	  provide netfilter compatible functionality via BPF
-
-if BPFILTER
-config BPFILTER_UMH
-	tristate "bpfilter kernel module with user mode helper"
-	depends on CC_CAN_LINK
-	depends on m || CC_CAN_LINK_STATIC
-	default m
-	help
-	  This builds bpfilter kernel module with embedded user mode helper
-
-	  Note: To compile this as built-in, your toolchain must support
-	  building static binaries, since rootfs isn't mounted at the time
-	  when __init functions are called and do_execv won't be able to find
-	  the elf interpreter.
-endif
diff --git a/net/bpfilter/Makefile b/net/bpfilter/Makefile
deleted file mode 100644
index cdac82b8c53a..000000000000
--- a/net/bpfilter/Makefile
+++ /dev/null
@@ -1,20 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0
-#
-# Makefile for the Linux BPFILTER layer.
-#
-
-userprogs := bpfilter_umh
-bpfilter_umh-objs := main.o
-userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi
-
-ifeq ($(CONFIG_BPFILTER_UMH), y)
-# builtin bpfilter_umh should be linked with -static
-# since rootfs isn't mounted at the time of __init
-# function is called and do_execv won't find elf interpreter
-userldflags += -static
-endif
-
-$(obj)/bpfilter_umh_blob.o: $(obj)/bpfilter_umh
-
-obj-$(CONFIG_BPFILTER_UMH) += bpfilter.o
-bpfilter-objs += bpfilter_kern.o bpfilter_umh_blob.o
diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
deleted file mode 100644
index 97e129e3f31c..000000000000
--- a/net/bpfilter/bpfilter_kern.c
+++ /dev/null
@@ -1,136 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-#include <linux/init.h>
-#include <linux/module.h>
-#include <linux/umh.h>
-#include <linux/bpfilter.h>
-#include <linux/sched.h>
-#include <linux/sched/signal.h>
-#include <linux/fs.h>
-#include <linux/file.h>
-#include "msgfmt.h"
-
-extern char bpfilter_umh_start;
-extern char bpfilter_umh_end;
-
-static void shutdown_umh(void)
-{
-	struct umd_info *info = &bpfilter_ops.info;
-	struct pid *tgid = info->tgid;
-
-	if (tgid) {
-		kill_pid(tgid, SIGKILL, 1);
-		wait_event(tgid->wait_pidfd, thread_group_exited(tgid));
-		umd_cleanup_helper(info);
-	}
-}
-
-static void __stop_umh(void)
-{
-	if (IS_ENABLED(CONFIG_INET))
-		shutdown_umh();
-}
-
-static int bpfilter_send_req(struct mbox_request *req)
-{
-	struct mbox_reply reply;
-	loff_t pos = 0;
-	ssize_t n;
-
-	if (!bpfilter_ops.info.tgid)
-		return -EFAULT;
-	pos = 0;
-	n = kernel_write(bpfilter_ops.info.pipe_to_umh, req, sizeof(*req),
-			   &pos);
-	if (n != sizeof(*req)) {
-		pr_err("write fail %zd\n", n);
-		goto stop;
-	}
-	pos = 0;
-	n = kernel_read(bpfilter_ops.info.pipe_from_umh, &reply, sizeof(reply),
-			&pos);
-	if (n != sizeof(reply)) {
-		pr_err("read fail %zd\n", n);
-		goto stop;
-	}
-	return reply.status;
-stop:
-	__stop_umh();
-	return -EFAULT;
-}
-
-static int bpfilter_process_sockopt(struct sock *sk, int optname,
-				    sockptr_t optval, unsigned int optlen,
-				    bool is_set)
-{
-	struct mbox_request req = {
-		.is_set		= is_set,
-		.pid		= current->pid,
-		.cmd		= optname,
-		.addr		= (uintptr_t)optval.user,
-		.len		= optlen,
-	};
-	if (sockptr_is_kernel(optval)) {
-		pr_err("kernel access not supported\n");
-		return -EFAULT;
-	}
-	return bpfilter_send_req(&req);
-}
-
-static int start_umh(void)
-{
-	struct mbox_request req = { .pid = current->pid };
-	int err;
-
-	/* fork usermode process */
-	err = fork_usermode_driver(&bpfilter_ops.info);
-	if (err)
-		return err;
-	pr_info("Loaded bpfilter_umh pid %d\n", pid_nr(bpfilter_ops.info.tgid));
-
-	/* health check that usermode process started correctly */
-	if (bpfilter_send_req(&req) != 0) {
-		shutdown_umh();
-		return -EFAULT;
-	}
-
-	return 0;
-}
-
-static int __init load_umh(void)
-{
-	int err;
-
-	err = umd_load_blob(&bpfilter_ops.info,
-			    &bpfilter_umh_start,
-			    &bpfilter_umh_end - &bpfilter_umh_start);
-	if (err)
-		return err;
-
-	mutex_lock(&bpfilter_ops.lock);
-	err = start_umh();
-	if (!err && IS_ENABLED(CONFIG_INET)) {
-		bpfilter_ops.sockopt = &bpfilter_process_sockopt;
-		bpfilter_ops.start = &start_umh;
-	}
-	mutex_unlock(&bpfilter_ops.lock);
-	if (err)
-		umd_unload_blob(&bpfilter_ops.info);
-	return err;
-}
-
-static void __exit fini_umh(void)
-{
-	mutex_lock(&bpfilter_ops.lock);
-	if (IS_ENABLED(CONFIG_INET)) {
-		shutdown_umh();
-		bpfilter_ops.start = NULL;
-		bpfilter_ops.sockopt = NULL;
-	}
-	mutex_unlock(&bpfilter_ops.lock);
-
-	umd_unload_blob(&bpfilter_ops.info);
-}
-module_init(load_umh);
-module_exit(fini_umh);
-MODULE_LICENSE("GPL");
diff --git a/net/bpfilter/bpfilter_umh_blob.S b/net/bpfilter/bpfilter_umh_blob.S
deleted file mode 100644
index 40311d10d2f2..000000000000
--- a/net/bpfilter/bpfilter_umh_blob.S
+++ /dev/null
@@ -1,7 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-	.section .init.rodata, "a"
-	.global bpfilter_umh_start
-bpfilter_umh_start:
-	.incbin "net/bpfilter/bpfilter_umh"
-	.global bpfilter_umh_end
-bpfilter_umh_end:
diff --git a/net/bpfilter/main.c b/net/bpfilter/main.c
deleted file mode 100644
index 291a92546246..000000000000
--- a/net/bpfilter/main.c
+++ /dev/null
@@ -1,64 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#define _GNU_SOURCE
-#include <sys/uio.h>
-#include <errno.h>
-#include <stdio.h>
-#include <sys/socket.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include "../../include/uapi/linux/bpf.h"
-#include <asm/unistd.h>
-#include "msgfmt.h"
-
-FILE *debug_f;
-
-static int handle_get_cmd(struct mbox_request *cmd)
-{
-	switch (cmd->cmd) {
-	case 0:
-		return 0;
-	default:
-		break;
-	}
-	return -ENOPROTOOPT;
-}
-
-static int handle_set_cmd(struct mbox_request *cmd)
-{
-	return -ENOPROTOOPT;
-}
-
-static void loop(void)
-{
-	while (1) {
-		struct mbox_request req;
-		struct mbox_reply reply;
-		int n;
-
-		n = read(0, &req, sizeof(req));
-		if (n != sizeof(req)) {
-			fprintf(debug_f, "invalid request %d\n", n);
-			return;
-		}
-
-		reply.status = req.is_set ?
-			handle_set_cmd(&req) :
-			handle_get_cmd(&req);
-
-		n = write(1, &reply, sizeof(reply));
-		if (n != sizeof(reply)) {
-			fprintf(debug_f, "reply failed %d\n", n);
-			return;
-		}
-	}
-}
-
-int main(void)
-{
-	debug_f = fopen("/dev/kmsg", "w");
-	setvbuf(debug_f, 0, _IOLBF, 0);
-	fprintf(debug_f, "<5>Started bpfilter\n");
-	loop();
-	fclose(debug_f);
-	return 0;
-}
diff --git a/net/bpfilter/msgfmt.h b/net/bpfilter/msgfmt.h
deleted file mode 100644
index 98d121c62945..000000000000
--- a/net/bpfilter/msgfmt.h
+++ /dev/null
@@ -1,17 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _NET_BPFILTER_MSGFMT_H
-#define _NET_BPFILTER_MSGFMT_H
-
-struct mbox_request {
-	__u64 addr;
-	__u32 len;
-	__u32 is_set;
-	__u32 cmd;
-	__u32 pid;
-};
-
-struct mbox_reply {
-	__u32 status;
-};
-
-#endif
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index e144a02a6a61..ec36d2ec059e 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -16,8 +16,6 @@ obj-y     := route.o inetpeer.o protocol.o \
 	     inet_fragment.o ping.o ip_tunnel_core.o gre_offload.o \
 	     metrics.o netlink.o nexthop.o udp_tunnel_stub.o
 
-obj-$(CONFIG_BPFILTER) += bpfilter/
-
 obj-$(CONFIG_NET_IP_TUNNEL) += ip_tunnel.o
 obj-$(CONFIG_SYSCTL) += sysctl_net_ipv4.o
 obj-$(CONFIG_PROC_FS) += proc.o
diff --git a/net/ipv4/bpfilter/Makefile b/net/ipv4/bpfilter/Makefile
deleted file mode 100644
index 00af5305e05a..000000000000
--- a/net/ipv4/bpfilter/Makefile
+++ /dev/null
@@ -1,2 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0-only
-obj-$(CONFIG_BPFILTER) += sockopt.o
diff --git a/net/ipv4/bpfilter/sockopt.c b/net/ipv4/bpfilter/sockopt.c
deleted file mode 100644
index 193bcc2acccc..000000000000
--- a/net/ipv4/bpfilter/sockopt.c
+++ /dev/null
@@ -1,71 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#include <linux/init.h>
-#include <linux/module.h>
-#include <linux/uaccess.h>
-#include <linux/bpfilter.h>
-#include <uapi/linux/bpf.h>
-#include <linux/wait.h>
-#include <linux/kmod.h>
-#include <linux/fs.h>
-#include <linux/file.h>
-
-struct bpfilter_umh_ops bpfilter_ops;
-EXPORT_SYMBOL_GPL(bpfilter_ops);
-
-static int bpfilter_mbox_request(struct sock *sk, int optname, sockptr_t optval,
-				 unsigned int optlen, bool is_set)
-{
-	int err;
-	mutex_lock(&bpfilter_ops.lock);
-	if (!bpfilter_ops.sockopt) {
-		mutex_unlock(&bpfilter_ops.lock);
-		request_module("bpfilter");
-		mutex_lock(&bpfilter_ops.lock);
-
-		if (!bpfilter_ops.sockopt) {
-			err = -ENOPROTOOPT;
-			goto out;
-		}
-	}
-	if (bpfilter_ops.info.tgid &&
-	    thread_group_exited(bpfilter_ops.info.tgid))
-		umd_cleanup_helper(&bpfilter_ops.info);
-
-	if (!bpfilter_ops.info.tgid) {
-		err = bpfilter_ops.start();
-		if (err)
-			goto out;
-	}
-	err = bpfilter_ops.sockopt(sk, optname, optval, optlen, is_set);
-out:
-	mutex_unlock(&bpfilter_ops.lock);
-	return err;
-}
-
-int bpfilter_ip_set_sockopt(struct sock *sk, int optname, sockptr_t optval,
-			    unsigned int optlen)
-{
-	return bpfilter_mbox_request(sk, optname, optval, optlen, true);
-}
-
-int bpfilter_ip_get_sockopt(struct sock *sk, int optname, char __user *optval,
-			    int __user *optlen)
-{
-	int len;
-
-	if (get_user(len, optlen))
-		return -EFAULT;
-
-	return bpfilter_mbox_request(sk, optname, USER_SOCKPTR(optval), len,
-				     false);
-}
-
-static int __init bpfilter_sockopt_init(void)
-{
-	mutex_init(&bpfilter_ops.lock);
-	bpfilter_ops.info.tgid = NULL;
-	bpfilter_ops.info.driver_name = "bpfilter_umh";
-
-	return 0;
-}
-device_initcall(bpfilter_sockopt_init);
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 66247e8b429e..7aa9dc0e6760 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -47,8 +47,6 @@
 #include <linux/errqueue.h>
 #include <linux/uaccess.h>
 
-#include <linux/bpfilter.h>
-
 /*
  *	SOL_IP control messages.
  */
@@ -1411,11 +1409,6 @@ int ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
 		return -ENOPROTOOPT;
 
 	err = do_ip_setsockopt(sk, level, optname, optval, optlen);
-#if IS_ENABLED(CONFIG_BPFILTER_UMH)
-	if (optname >= BPFILTER_IPT_SO_SET_REPLACE &&
-	    optname < BPFILTER_IPT_SET_MAX)
-		err = bpfilter_ip_set_sockopt(sk, optname, optval, optlen);
-#endif
 #ifdef CONFIG_NETFILTER
 	/* we need to exclude all possible ENOPROTOOPTs except default case */
 	if (err == -ENOPROTOOPT && optname != IP_HDRINCL &&
@@ -1763,11 +1756,6 @@ int ip_getsockopt(struct sock *sk, int level,
 	err = do_ip_getsockopt(sk, level, optname,
 			       USER_SOCKPTR(optval), USER_SOCKPTR(optlen));
 
-#if IS_ENABLED(CONFIG_BPFILTER_UMH)
-	if (optname >= BPFILTER_IPT_SO_GET_INFO &&
-	    optname < BPFILTER_IPT_GET_MAX)
-		err = bpfilter_ip_get_sockopt(sk, optname, optval, optlen);
-#endif
 #ifdef CONFIG_NETFILTER
 	/* we need to exclude all possible ENOPROTOOPTs except default case */
 	if (err == -ENOPROTOOPT && optname != IP_PKTOPTIONS &&
diff --git a/net/unix/unix_bpf.c b/net/unix/unix_bpf.c
index 7ea7c3a0d0d0..bd84785bf8d6 100644
--- a/net/unix/unix_bpf.c
+++ b/net/unix/unix_bpf.c
@@ -161,15 +161,30 @@ int unix_stream_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool r
 {
 	struct sock *sk_pair;
 
+	/* Restore does not decrement the sk_pair reference yet because we must
+	 * keep the a reference to the socket until after an RCU grace period
+	 * and any pending sends have completed.
+	 */
 	if (restore) {
 		sk->sk_write_space = psock->saved_write_space;
 		sock_replace_proto(sk, psock->sk_proto);
 		return 0;
 	}
 
-	sk_pair = unix_peer(sk);
-	sock_hold(sk_pair);
-	psock->sk_pair = sk_pair;
+	/* psock_update_sk_prot can be called multiple times if psock is
+	 * added to multiple maps and/or slots in the same map. There is
+	 * also an edge case where replacing a psock with itself can trigger
+	 * an extra psock_update_sk_prot during the insert process. So it
+	 * must be safe to do multiple calls. Here we need to ensure we don't
+	 * increment the refcnt through sock_hold many times. There will only
+	 * be a single matching destroy operation.
+	 */
+	if (!psock->sk_pair) {
+		sk_pair = unix_peer(sk);
+		sock_hold(sk_pair);
+		psock->sk_pair = sk_pair;
+	}
+
 	unix_stream_bpf_check_needs_rebuild(psock->sk_proto);
 	sock_replace_proto(sk, &unix_stream_bpf_prot);
 	return 0;