From 005142b8a1f0f32d33fbe04b728464c1b7acfa0e Mon Sep 17 00:00:00 2001
From: Alexei Starovoitov <ast@kernel.org>
Date: Tue, 18 Aug 2020 21:27:56 -0700
Subject: bpf: Factor out bpf_link_by_id() helper.

Refactor the code a bit to extract bpf_link_by_id() helper.
It's similar to existing bpf_prog_by_id().

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200819042759.51280-2-alexei.starovoitov@gmail.com
---
 kernel/bpf/syscall.c | 46 ++++++++++++++++++++++++++++------------------
 1 file changed, 28 insertions(+), 18 deletions(-)

(limited to 'kernel')

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 86299a292214..689d736b6904 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -4014,40 +4014,50 @@ static int link_detach(union bpf_attr *attr)
 	return ret;
 }
 
-static int bpf_link_inc_not_zero(struct bpf_link *link)
+static struct bpf_link *bpf_link_inc_not_zero(struct bpf_link *link)
 {
-	return atomic64_fetch_add_unless(&link->refcnt, 1, 0) ? 0 : -ENOENT;
+	return atomic64_fetch_add_unless(&link->refcnt, 1, 0) ? link : ERR_PTR(-ENOENT);
 }
 
-#define BPF_LINK_GET_FD_BY_ID_LAST_FIELD link_id
-
-static int bpf_link_get_fd_by_id(const union bpf_attr *attr)
+struct bpf_link *bpf_link_by_id(u32 id)
 {
 	struct bpf_link *link;
-	u32 id = attr->link_id;
-	int fd, err;
 
-	if (CHECK_ATTR(BPF_LINK_GET_FD_BY_ID))
-		return -EINVAL;
-
-	if (!capable(CAP_SYS_ADMIN))
-		return -EPERM;
+	if (!id)
+		return ERR_PTR(-ENOENT);
 
 	spin_lock_bh(&link_idr_lock);
-	link = idr_find(&link_idr, id);
 	/* before link is "settled", ID is 0, pretend it doesn't exist yet */
+	link = idr_find(&link_idr, id);
 	if (link) {
 		if (link->id)
-			err = bpf_link_inc_not_zero(link);
+			link = bpf_link_inc_not_zero(link);
 		else
-			err = -EAGAIN;
+			link = ERR_PTR(-EAGAIN);
 	} else {
-		err = -ENOENT;
+		link = ERR_PTR(-ENOENT);
 	}
 	spin_unlock_bh(&link_idr_lock);
+	return link;
+}
 
-	if (err)
-		return err;
+#define BPF_LINK_GET_FD_BY_ID_LAST_FIELD link_id
+
+static int bpf_link_get_fd_by_id(const union bpf_attr *attr)
+{
+	struct bpf_link *link;
+	u32 id = attr->link_id;
+	int fd;
+
+	if (CHECK_ATTR(BPF_LINK_GET_FD_BY_ID))
+		return -EINVAL;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	link = bpf_link_by_id(id);
+	if (IS_ERR(link))
+		return PTR_ERR(link);
 
 	fd = bpf_link_new_fd(link);
 	if (fd < 0)
-- 
cgit v1.2.3


From f0fdfefb2d4da5b76c3f810be0edb2ab90360224 Mon Sep 17 00:00:00 2001
From: Alexei Starovoitov <ast@kernel.org>
Date: Tue, 18 Aug 2020 21:27:57 -0700
Subject: bpf: Add BPF program and map iterators as built-in BPF programs.

The program and map iterators work similar to seq_file-s.
Once the program is pinned in bpffs it can be read with "cat" tool
to print human readable output. In this case about BPF programs and maps.
For example:
$ cat /sys/fs/bpf/progs.debug
  id name            attached
   5 dump_bpf_map    bpf_iter_bpf_map
   6 dump_bpf_prog   bpf_iter_bpf_prog
$ cat /sys/fs/bpf/maps.debug
  id name            max_entries
   3 iterator.rodata     1

To avoid kernel build dependency on clang 10 separate bpf skeleton generation
into manual "make" step and instead check-in generated .skel.h into git.

Unlike 'bpftool prog show' in-kernel BTF name is used (when available)
to print full name of BPF program instead of 16-byte truncated name.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200819042759.51280-3-alexei.starovoitov@gmail.com
---
 kernel/bpf/preload/iterators/.gitignore       |   2 +
 kernel/bpf/preload/iterators/Makefile         |  57 ++++
 kernel/bpf/preload/iterators/README           |   4 +
 kernel/bpf/preload/iterators/iterators.bpf.c  | 114 +++++++
 kernel/bpf/preload/iterators/iterators.skel.h | 410 ++++++++++++++++++++++++++
 5 files changed, 587 insertions(+)
 create mode 100644 kernel/bpf/preload/iterators/.gitignore
 create mode 100644 kernel/bpf/preload/iterators/Makefile
 create mode 100644 kernel/bpf/preload/iterators/README
 create mode 100644 kernel/bpf/preload/iterators/iterators.bpf.c
 create mode 100644 kernel/bpf/preload/iterators/iterators.skel.h

(limited to 'kernel')

diff --git a/kernel/bpf/preload/iterators/.gitignore b/kernel/bpf/preload/iterators/.gitignore
new file mode 100644
index 000000000000..ffdb70230c8b
--- /dev/null
+++ b/kernel/bpf/preload/iterators/.gitignore
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+/.output
diff --git a/kernel/bpf/preload/iterators/Makefile b/kernel/bpf/preload/iterators/Makefile
new file mode 100644
index 000000000000..28fa8c1440f4
--- /dev/null
+++ b/kernel/bpf/preload/iterators/Makefile
@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: GPL-2.0
+OUTPUT := .output
+CLANG ?= clang
+LLC ?= llc
+LLVM_STRIP ?= llvm-strip
+DEFAULT_BPFTOOL := $(OUTPUT)/sbin/bpftool
+BPFTOOL ?= $(DEFAULT_BPFTOOL)
+LIBBPF_SRC := $(abspath ../../../../tools/lib/bpf)
+BPFOBJ := $(OUTPUT)/libbpf.a
+BPF_INCLUDE := $(OUTPUT)
+INCLUDES := -I$(OUTPUT) -I$(BPF_INCLUDE) -I$(abspath ../../../../tools/lib)        \
+       -I$(abspath ../../../../tools/include/uapi)
+CFLAGS := -g -Wall
+
+abs_out := $(abspath $(OUTPUT))
+ifeq ($(V),1)
+Q =
+msg =
+else
+Q = @
+msg = @printf '  %-8s %s%s\n' "$(1)" "$(notdir $(2))" "$(if $(3), $(3))";
+MAKEFLAGS += --no-print-directory
+submake_extras := feature_display=0
+endif
+
+.DELETE_ON_ERROR:
+
+.PHONY: all clean
+
+all: iterators.skel.h
+
+clean:
+	$(call msg,CLEAN)
+	$(Q)rm -rf $(OUTPUT) iterators
+
+iterators.skel.h: $(OUTPUT)/iterators.bpf.o | $(BPFTOOL)
+	$(call msg,GEN-SKEL,$@)
+	$(Q)$(BPFTOOL) gen skeleton $< > $@
+
+
+$(OUTPUT)/iterators.bpf.o: iterators.bpf.c $(BPFOBJ) | $(OUTPUT)
+	$(call msg,BPF,$@)
+	$(Q)$(CLANG) -g -O2 -target bpf $(INCLUDES)			      \
+		 -c $(filter %.c,$^) -o $@ &&				      \
+	$(LLVM_STRIP) -g $@
+
+$(OUTPUT):
+	$(call msg,MKDIR,$@)
+	$(Q)mkdir -p $(OUTPUT)
+
+$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(OUTPUT)
+	$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC)			       \
+		    OUTPUT=$(abspath $(dir $@))/ $(abspath $@)
+
+$(DEFAULT_BPFTOOL):
+	$(Q)$(MAKE) $(submake_extras) -C ../../../../tools/bpf/bpftool			      \
+		    prefix= OUTPUT=$(abs_out)/ DESTDIR=$(abs_out) install
diff --git a/kernel/bpf/preload/iterators/README b/kernel/bpf/preload/iterators/README
new file mode 100644
index 000000000000..7fd6d39a9ad2
--- /dev/null
+++ b/kernel/bpf/preload/iterators/README
@@ -0,0 +1,4 @@
+WARNING:
+If you change "iterators.bpf.c" do "make -j" in this directory to rebuild "iterators.skel.h".
+Make sure to have clang 10 installed.
+See Documentation/bpf/bpf_devel_QA.rst
diff --git a/kernel/bpf/preload/iterators/iterators.bpf.c b/kernel/bpf/preload/iterators/iterators.bpf.c
new file mode 100644
index 000000000000..5ded550b2ed6
--- /dev/null
+++ b/kernel/bpf/preload/iterators/iterators.bpf.c
@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Facebook */
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_core_read.h>
+
+#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)
+struct seq_file;
+struct bpf_iter_meta {
+	struct seq_file *seq;
+	__u64 session_id;
+	__u64 seq_num;
+};
+
+struct bpf_map {
+	__u32 id;
+	char name[16];
+	__u32 max_entries;
+};
+
+struct bpf_iter__bpf_map {
+	struct bpf_iter_meta *meta;
+	struct bpf_map *map;
+};
+
+struct btf_type {
+	__u32 name_off;
+};
+
+struct btf_header {
+	__u32   str_len;
+};
+
+struct btf {
+	const char *strings;
+	struct btf_type **types;
+	struct btf_header hdr;
+};
+
+struct bpf_prog_aux {
+	__u32 id;
+	char name[16];
+	const char *attach_func_name;
+	struct bpf_prog *linked_prog;
+	struct bpf_func_info *func_info;
+	struct btf *btf;
+};
+
+struct bpf_prog {
+	struct bpf_prog_aux *aux;
+};
+
+struct bpf_iter__bpf_prog {
+	struct bpf_iter_meta *meta;
+	struct bpf_prog *prog;
+};
+#pragma clang attribute pop
+
+static const char *get_name(struct btf *btf, long btf_id, const char *fallback)
+{
+	struct btf_type **types, *t;
+	unsigned int name_off;
+	const char *str;
+
+	if (!btf)
+		return fallback;
+	str = btf->strings;
+	types = btf->types;
+	bpf_probe_read_kernel(&t, sizeof(t), types + btf_id);
+	name_off = BPF_CORE_READ(t, name_off);
+	if (name_off >= btf->hdr.str_len)
+		return fallback;
+	return str + name_off;
+}
+
+SEC("iter/bpf_map")
+int dump_bpf_map(struct bpf_iter__bpf_map *ctx)
+{
+	struct seq_file *seq = ctx->meta->seq;
+	__u64 seq_num = ctx->meta->seq_num;
+	struct bpf_map *map = ctx->map;
+
+	if (!map)
+		return 0;
+
+	if (seq_num == 0)
+		BPF_SEQ_PRINTF(seq, "  id name             max_entries\n");
+
+	BPF_SEQ_PRINTF(seq, "%4u %-16s%6d\n", map->id, map->name, map->max_entries);
+	return 0;
+}
+
+SEC("iter/bpf_prog")
+int dump_bpf_prog(struct bpf_iter__bpf_prog *ctx)
+{
+	struct seq_file *seq = ctx->meta->seq;
+	__u64 seq_num = ctx->meta->seq_num;
+	struct bpf_prog *prog = ctx->prog;
+	struct bpf_prog_aux *aux;
+
+	if (!prog)
+		return 0;
+
+	aux = prog->aux;
+	if (seq_num == 0)
+		BPF_SEQ_PRINTF(seq, "  id name             attached\n");
+
+	BPF_SEQ_PRINTF(seq, "%4u %-16s %s %s\n", aux->id,
+		       get_name(aux->btf, aux->func_info[0].type_id, aux->name),
+		       aux->attach_func_name, aux->linked_prog->aux->name);
+	return 0;
+}
+char LICENSE[] SEC("license") = "GPL";
diff --git a/kernel/bpf/preload/iterators/iterators.skel.h b/kernel/bpf/preload/iterators/iterators.skel.h
new file mode 100644
index 000000000000..c3171357dc4f
--- /dev/null
+++ b/kernel/bpf/preload/iterators/iterators.skel.h
@@ -0,0 +1,410 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+
+/* THIS FILE IS AUTOGENERATED! */
+#ifndef __ITERATORS_BPF_SKEL_H__
+#define __ITERATORS_BPF_SKEL_H__
+
+#include <stdlib.h>
+#include <bpf/libbpf.h>
+
+struct iterators_bpf {
+	struct bpf_object_skeleton *skeleton;
+	struct bpf_object *obj;
+	struct {
+		struct bpf_map *rodata;
+	} maps;
+	struct {
+		struct bpf_program *dump_bpf_map;
+		struct bpf_program *dump_bpf_prog;
+	} progs;
+	struct {
+		struct bpf_link *dump_bpf_map;
+		struct bpf_link *dump_bpf_prog;
+	} links;
+	struct iterators_bpf__rodata {
+		char dump_bpf_map____fmt[35];
+		char dump_bpf_map____fmt_1[14];
+		char dump_bpf_prog____fmt[32];
+		char dump_bpf_prog____fmt_2[17];
+	} *rodata;
+};
+
+static void
+iterators_bpf__destroy(struct iterators_bpf *obj)
+{
+	if (!obj)
+		return;
+	if (obj->skeleton)
+		bpf_object__destroy_skeleton(obj->skeleton);
+	free(obj);
+}
+
+static inline int
+iterators_bpf__create_skeleton(struct iterators_bpf *obj);
+
+static inline struct iterators_bpf *
+iterators_bpf__open_opts(const struct bpf_object_open_opts *opts)
+{
+	struct iterators_bpf *obj;
+
+	obj = (typeof(obj))calloc(1, sizeof(*obj));
+	if (!obj)
+		return NULL;
+	if (iterators_bpf__create_skeleton(obj))
+		goto err;
+	if (bpf_object__open_skeleton(obj->skeleton, opts))
+		goto err;
+
+	return obj;
+err:
+	iterators_bpf__destroy(obj);
+	return NULL;
+}
+
+static inline struct iterators_bpf *
+iterators_bpf__open(void)
+{
+	return iterators_bpf__open_opts(NULL);
+}
+
+static inline int
+iterators_bpf__load(struct iterators_bpf *obj)
+{
+	return bpf_object__load_skeleton(obj->skeleton);
+}
+
+static inline struct iterators_bpf *
+iterators_bpf__open_and_load(void)
+{
+	struct iterators_bpf *obj;
+
+	obj = iterators_bpf__open();
+	if (!obj)
+		return NULL;
+	if (iterators_bpf__load(obj)) {
+		iterators_bpf__destroy(obj);
+		return NULL;
+	}
+	return obj;
+}
+
+static inline int
+iterators_bpf__attach(struct iterators_bpf *obj)
+{
+	return bpf_object__attach_skeleton(obj->skeleton);
+}
+
+static inline void
+iterators_bpf__detach(struct iterators_bpf *obj)
+{
+	return bpf_object__detach_skeleton(obj->skeleton);
+}
+
+static inline int
+iterators_bpf__create_skeleton(struct iterators_bpf *obj)
+{
+	struct bpf_object_skeleton *s;
+
+	s = (typeof(s))calloc(1, sizeof(*s));
+	if (!s)
+		return -1;
+	obj->skeleton = s;
+
+	s->sz = sizeof(*s);
+	s->name = "iterators_bpf";
+	s->obj = &obj->obj;
+
+	/* maps */
+	s->map_cnt = 1;
+	s->map_skel_sz = sizeof(*s->maps);
+	s->maps = (typeof(s->maps))calloc(s->map_cnt, s->map_skel_sz);
+	if (!s->maps)
+		goto err;
+
+	s->maps[0].name = "iterator.rodata";
+	s->maps[0].map = &obj->maps.rodata;
+	s->maps[0].mmaped = (void **)&obj->rodata;
+
+	/* programs */
+	s->prog_cnt = 2;
+	s->prog_skel_sz = sizeof(*s->progs);
+	s->progs = (typeof(s->progs))calloc(s->prog_cnt, s->prog_skel_sz);
+	if (!s->progs)
+		goto err;
+
+	s->progs[0].name = "dump_bpf_map";
+	s->progs[0].prog = &obj->progs.dump_bpf_map;
+	s->progs[0].link = &obj->links.dump_bpf_map;
+
+	s->progs[1].name = "dump_bpf_prog";
+	s->progs[1].prog = &obj->progs.dump_bpf_prog;
+	s->progs[1].link = &obj->links.dump_bpf_prog;
+
+	s->data_sz = 7128;
+	s->data = (void *)"\
+\x7f\x45\x4c\x46\x02\x01\x01\0\0\0\0\0\0\0\0\0\x01\0\xf7\0\x01\0\0\0\0\0\0\0\0\
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+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x20\x13\0\0\0\0\0\0\xe0\x03\0\0\0\0\0\0\x08\0\0\
+\0\x07\0\0\0\x08\0\0\0\0\0\0\0\x10\0\0\0\0\0\0\0\x7b\0\0\0\x03\x4c\xff\x6f\0\0\
+\0\x80\0\0\0\0\0\0\0\0\0\0\0\0\0\x17\0\0\0\0\0\0\x07\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\x01\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x91\0\0\0\x03\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\x07\x17\0\0\0\0\0\0\x0a\x01\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x01\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0";
+
+	return 0;
+err:
+	bpf_object__destroy_skeleton(s);
+	return -1;
+}
+
+#endif /* __ITERATORS_BPF_SKEL_H__ */
-- 
cgit v1.2.3


From d71fa5c9763c24dd997a2fa4feb7a13a95bab42c Mon Sep 17 00:00:00 2001
From: Alexei Starovoitov <ast@kernel.org>
Date: Tue, 18 Aug 2020 21:27:58 -0700
Subject: bpf: Add kernel module with user mode driver that populates bpffs.

Add kernel module with user mode driver that populates bpffs with
BPF iterators.

$ mount bpffs /my/bpffs/ -t bpf
$ ls -la /my/bpffs/
total 4
drwxrwxrwt  2 root root    0 Jul  2 00:27 .
drwxr-xr-x 19 root root 4096 Jul  2 00:09 ..
-rw-------  1 root root    0 Jul  2 00:27 maps.debug
-rw-------  1 root root    0 Jul  2 00:27 progs.debug

The user mode driver will load BPF Type Formats, create BPF maps, populate BPF
maps, load two BPF programs, attach them to BPF iterators, and finally send two
bpf_link IDs back to the kernel.
The kernel will pin two bpf_links into newly mounted bpffs instance under
names "progs.debug" and "maps.debug". These two files become human readable.

$ cat /my/bpffs/progs.debug
  id name            attached
  11 dump_bpf_map    bpf_iter_bpf_map
  12 dump_bpf_prog   bpf_iter_bpf_prog
  27 test_pkt_access
  32 test_main       test_pkt_access test_pkt_access
  33 test_subprog1   test_pkt_access_subprog1 test_pkt_access
  34 test_subprog2   test_pkt_access_subprog2 test_pkt_access
  35 test_subprog3   test_pkt_access_subprog3 test_pkt_access
  36 new_get_skb_len get_skb_len test_pkt_access
  37 new_get_skb_ifindex get_skb_ifindex test_pkt_access
  38 new_get_constant get_constant test_pkt_access

The BPF program dump_bpf_prog() in iterators.bpf.c is printing this data about
all BPF programs currently loaded in the system. This information is unstable
and will change from kernel to kernel as ".debug" suffix conveys.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200819042759.51280-4-alexei.starovoitov@gmail.com
---
 kernel/Makefile                                   |   2 +-
 kernel/bpf/Makefile                               |   1 +
 kernel/bpf/inode.c                                | 116 +++++++++++++++++++++-
 kernel/bpf/preload/Kconfig                        |  23 +++++
 kernel/bpf/preload/Makefile                       |  23 +++++
 kernel/bpf/preload/bpf_preload.h                  |  16 +++
 kernel/bpf/preload/bpf_preload_kern.c             |  91 +++++++++++++++++
 kernel/bpf/preload/bpf_preload_umd_blob.S         |   7 ++
 kernel/bpf/preload/iterators/bpf_preload_common.h |  13 +++
 kernel/bpf/preload/iterators/iterators.c          |  94 ++++++++++++++++++
 10 files changed, 382 insertions(+), 4 deletions(-)
 create mode 100644 kernel/bpf/preload/Kconfig
 create mode 100644 kernel/bpf/preload/Makefile
 create mode 100644 kernel/bpf/preload/bpf_preload.h
 create mode 100644 kernel/bpf/preload/bpf_preload_kern.c
 create mode 100644 kernel/bpf/preload/bpf_preload_umd_blob.S
 create mode 100644 kernel/bpf/preload/iterators/bpf_preload_common.h
 create mode 100644 kernel/bpf/preload/iterators/iterators.c

(limited to 'kernel')

diff --git a/kernel/Makefile b/kernel/Makefile
index 9a20016d4900..22b0760660fc 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -12,7 +12,7 @@ obj-y     = fork.o exec_domain.o panic.o \
 	    notifier.o ksysfs.o cred.o reboot.o \
 	    async.o range.o smpboot.o ucount.o regset.o
 
-obj-$(CONFIG_BPFILTER) += usermode_driver.o
+obj-$(CONFIG_USERMODE_DRIVER) += usermode_driver.o
 obj-$(CONFIG_MODULES) += kmod.o
 obj-$(CONFIG_MULTIUSER) += groups.o
 
diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile
index e6eb9c0402da..19e137aae40e 100644
--- a/kernel/bpf/Makefile
+++ b/kernel/bpf/Makefile
@@ -29,3 +29,4 @@ ifeq ($(CONFIG_BPF_JIT),y)
 obj-$(CONFIG_BPF_SYSCALL) += bpf_struct_ops.o
 obj-${CONFIG_BPF_LSM} += bpf_lsm.o
 endif
+obj-$(CONFIG_BPF_PRELOAD) += preload/
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index fb878ba3f22f..b48a56f53495 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -20,6 +20,7 @@
 #include <linux/filter.h>
 #include <linux/bpf.h>
 #include <linux/bpf_trace.h>
+#include "preload/bpf_preload.h"
 
 enum bpf_type {
 	BPF_TYPE_UNSPEC	= 0,
@@ -369,9 +370,10 @@ static struct dentry *
 bpf_lookup(struct inode *dir, struct dentry *dentry, unsigned flags)
 {
 	/* Dots in names (e.g. "/sys/fs/bpf/foo.bar") are reserved for future
-	 * extensions.
+	 * extensions. That allows popoulate_bpffs() create special files.
 	 */
-	if (strchr(dentry->d_name.name, '.'))
+	if ((dir->i_mode & S_IALLUGO) &&
+	    strchr(dentry->d_name.name, '.'))
 		return ERR_PTR(-EPERM);
 
 	return simple_lookup(dir, dentry, flags);
@@ -409,6 +411,27 @@ static const struct inode_operations bpf_dir_iops = {
 	.unlink		= simple_unlink,
 };
 
+/* pin iterator link into bpffs */
+static int bpf_iter_link_pin_kernel(struct dentry *parent,
+				    const char *name, struct bpf_link *link)
+{
+	umode_t mode = S_IFREG | S_IRUSR;
+	struct dentry *dentry;
+	int ret;
+
+	inode_lock(parent->d_inode);
+	dentry = lookup_one_len(name, parent, strlen(name));
+	if (IS_ERR(dentry)) {
+		inode_unlock(parent->d_inode);
+		return PTR_ERR(dentry);
+	}
+	ret = bpf_mkobj_ops(dentry, mode, link, &bpf_link_iops,
+			    &bpf_iter_fops);
+	dput(dentry);
+	inode_unlock(parent->d_inode);
+	return ret;
+}
+
 static int bpf_obj_do_pin(const char __user *pathname, void *raw,
 			  enum bpf_type type)
 {
@@ -638,6 +661,91 @@ static int bpf_parse_param(struct fs_context *fc, struct fs_parameter *param)
 	return 0;
 }
 
+struct bpf_preload_ops *bpf_preload_ops;
+EXPORT_SYMBOL_GPL(bpf_preload_ops);
+
+static bool bpf_preload_mod_get(void)
+{
+	/* If bpf_preload.ko wasn't loaded earlier then load it now.
+	 * When bpf_preload is built into vmlinux the module's __init
+	 * function will populate it.
+	 */
+	if (!bpf_preload_ops) {
+		request_module("bpf_preload");
+		if (!bpf_preload_ops)
+			return false;
+	}
+	/* And grab the reference, so the module doesn't disappear while the
+	 * kernel is interacting with the kernel module and its UMD.
+	 */
+	if (!try_module_get(bpf_preload_ops->owner)) {
+		pr_err("bpf_preload module get failed.\n");
+		return false;
+	}
+	return true;
+}
+
+static void bpf_preload_mod_put(void)
+{
+	if (bpf_preload_ops)
+		/* now user can "rmmod bpf_preload" if necessary */
+		module_put(bpf_preload_ops->owner);
+}
+
+static DEFINE_MUTEX(bpf_preload_lock);
+
+static int populate_bpffs(struct dentry *parent)
+{
+	struct bpf_preload_info objs[BPF_PRELOAD_LINKS] = {};
+	struct bpf_link *links[BPF_PRELOAD_LINKS] = {};
+	int err = 0, i;
+
+	/* grab the mutex to make sure the kernel interactions with bpf_preload
+	 * UMD are serialized
+	 */
+	mutex_lock(&bpf_preload_lock);
+
+	/* if bpf_preload.ko wasn't built into vmlinux then load it */
+	if (!bpf_preload_mod_get())
+		goto out;
+
+	if (!bpf_preload_ops->info.tgid) {
+		/* preload() will start UMD that will load BPF iterator programs */
+		err = bpf_preload_ops->preload(objs);
+		if (err)
+			goto out_put;
+		for (i = 0; i < BPF_PRELOAD_LINKS; i++) {
+			links[i] = bpf_link_by_id(objs[i].link_id);
+			if (IS_ERR(links[i])) {
+				err = PTR_ERR(links[i]);
+				goto out_put;
+			}
+		}
+		for (i = 0; i < BPF_PRELOAD_LINKS; i++) {
+			err = bpf_iter_link_pin_kernel(parent,
+						       objs[i].link_name, links[i]);
+			if (err)
+				goto out_put;
+			/* do not unlink successfully pinned links even
+			 * if later link fails to pin
+			 */
+			links[i] = NULL;
+		}
+		/* finish() will tell UMD process to exit */
+		err = bpf_preload_ops->finish();
+		if (err)
+			goto out_put;
+	}
+out_put:
+	bpf_preload_mod_put();
+out:
+	mutex_unlock(&bpf_preload_lock);
+	for (i = 0; i < BPF_PRELOAD_LINKS && err; i++)
+		if (!IS_ERR_OR_NULL(links[i]))
+			bpf_link_put(links[i]);
+	return err;
+}
+
 static int bpf_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	static const struct tree_descr bpf_rfiles[] = { { "" } };
@@ -654,8 +762,8 @@ static int bpf_fill_super(struct super_block *sb, struct fs_context *fc)
 	inode = sb->s_root->d_inode;
 	inode->i_op = &bpf_dir_iops;
 	inode->i_mode &= ~S_IALLUGO;
+	populate_bpffs(sb->s_root);
 	inode->i_mode |= S_ISVTX | opts->mode;
-
 	return 0;
 }
 
@@ -705,6 +813,8 @@ static int __init bpf_init(void)
 {
 	int ret;
 
+	mutex_init(&bpf_preload_lock);
+
 	ret = sysfs_create_mount_point(fs_kobj, "bpf");
 	if (ret)
 		return ret;
diff --git a/kernel/bpf/preload/Kconfig b/kernel/bpf/preload/Kconfig
new file mode 100644
index 000000000000..7144e2d01ee4
--- /dev/null
+++ b/kernel/bpf/preload/Kconfig
@@ -0,0 +1,23 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config USERMODE_DRIVER
+	bool
+	default n
+
+menuconfig BPF_PRELOAD
+	bool "Preload BPF file system with kernel specific program and map iterators"
+	depends on BPF
+	select USERMODE_DRIVER
+	help
+	  This builds kernel module with several embedded BPF programs that are
+	  pinned into BPF FS mount point as human readable files that are
+	  useful in debugging and introspection of BPF programs and maps.
+
+if BPF_PRELOAD
+config BPF_PRELOAD_UMD
+	tristate "bpf_preload kernel module with user mode driver"
+	depends on CC_CAN_LINK
+	depends on m || CC_CAN_LINK_STATIC
+	default m
+	help
+	  This builds bpf_preload kernel module with embedded user mode driver.
+endif
diff --git a/kernel/bpf/preload/Makefile b/kernel/bpf/preload/Makefile
new file mode 100644
index 000000000000..12c7b62b9b6e
--- /dev/null
+++ b/kernel/bpf/preload/Makefile
@@ -0,0 +1,23 @@
+# SPDX-License-Identifier: GPL-2.0
+
+LIBBPF_SRCS = $(srctree)/tools/lib/bpf/
+LIBBPF_A = $(obj)/libbpf.a
+LIBBPF_OUT = $(abspath $(obj))
+
+$(LIBBPF_A):
+	$(Q)$(MAKE) -C $(LIBBPF_SRCS) OUTPUT=$(LIBBPF_OUT)/ $(LIBBPF_OUT)/libbpf.a
+
+userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi \
+	-I $(srctree)/tools/lib/ -Wno-unused-result
+
+userprogs := bpf_preload_umd
+
+bpf_preload_umd-objs := iterators/iterators.o
+bpf_preload_umd-userldlibs := $(LIBBPF_A) -lelf -lz
+
+$(obj)/bpf_preload_umd: $(LIBBPF_A)
+
+$(obj)/bpf_preload_umd_blob.o: $(obj)/bpf_preload_umd
+
+obj-$(CONFIG_BPF_PRELOAD_UMD) += bpf_preload.o
+bpf_preload-objs += bpf_preload_kern.o bpf_preload_umd_blob.o
diff --git a/kernel/bpf/preload/bpf_preload.h b/kernel/bpf/preload/bpf_preload.h
new file mode 100644
index 000000000000..2f9932276f2e
--- /dev/null
+++ b/kernel/bpf/preload/bpf_preload.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BPF_PRELOAD_H
+#define _BPF_PRELOAD_H
+
+#include <linux/usermode_driver.h>
+#include "iterators/bpf_preload_common.h"
+
+struct bpf_preload_ops {
+        struct umd_info info;
+	int (*preload)(struct bpf_preload_info *);
+	int (*finish)(void);
+	struct module *owner;
+};
+extern struct bpf_preload_ops *bpf_preload_ops;
+#define BPF_PRELOAD_LINKS 2
+#endif
diff --git a/kernel/bpf/preload/bpf_preload_kern.c b/kernel/bpf/preload/bpf_preload_kern.c
new file mode 100644
index 000000000000..79c5772465f1
--- /dev/null
+++ b/kernel/bpf/preload/bpf_preload_kern.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/pid.h>
+#include <linux/fs.h>
+#include <linux/sched/signal.h>
+#include "bpf_preload.h"
+
+extern char bpf_preload_umd_start;
+extern char bpf_preload_umd_end;
+
+static int preload(struct bpf_preload_info *obj);
+static int finish(void);
+
+static struct bpf_preload_ops umd_ops = {
+	.info.driver_name = "bpf_preload",
+	.preload = preload,
+	.finish = finish,
+	.owner = THIS_MODULE,
+};
+
+static int preload(struct bpf_preload_info *obj)
+{
+	int magic = BPF_PRELOAD_START;
+	loff_t pos = 0;
+	int i, err;
+	ssize_t n;
+
+	err = fork_usermode_driver(&umd_ops.info);
+	if (err)
+		return err;
+
+	/* send the start magic to let UMD proceed with loading BPF progs */
+	n = kernel_write(umd_ops.info.pipe_to_umh,
+			 &magic, sizeof(magic), &pos);
+	if (n != sizeof(magic))
+		return -EPIPE;
+
+	/* receive bpf_link IDs and names from UMD */
+	pos = 0;
+	for (i = 0; i < BPF_PRELOAD_LINKS; i++) {
+		n = kernel_read(umd_ops.info.pipe_from_umh,
+				&obj[i], sizeof(*obj), &pos);
+		if (n != sizeof(*obj))
+			return -EPIPE;
+	}
+	return 0;
+}
+
+static int finish(void)
+{
+	int magic = BPF_PRELOAD_END;
+	struct pid *tgid;
+	loff_t pos = 0;
+	ssize_t n;
+
+	/* send the last magic to UMD. It will do a normal exit. */
+	n = kernel_write(umd_ops.info.pipe_to_umh,
+			 &magic, sizeof(magic), &pos);
+	if (n != sizeof(magic))
+		return -EPIPE;
+	tgid = umd_ops.info.tgid;
+	wait_event(tgid->wait_pidfd, thread_group_exited(tgid));
+	umd_ops.info.tgid = NULL;
+	return 0;
+}
+
+static int __init load_umd(void)
+{
+	int err;
+
+	err = umd_load_blob(&umd_ops.info, &bpf_preload_umd_start,
+			    &bpf_preload_umd_end - &bpf_preload_umd_start);
+	if (err)
+		return err;
+	bpf_preload_ops = &umd_ops;
+	return err;
+}
+
+static void __exit fini_umd(void)
+{
+	bpf_preload_ops = NULL;
+	/* kill UMD in case it's still there due to earlier error */
+	kill_pid(umd_ops.info.tgid, SIGKILL, 1);
+	umd_ops.info.tgid = NULL;
+	umd_unload_blob(&umd_ops.info);
+}
+late_initcall(load_umd);
+module_exit(fini_umd);
+MODULE_LICENSE("GPL");
diff --git a/kernel/bpf/preload/bpf_preload_umd_blob.S b/kernel/bpf/preload/bpf_preload_umd_blob.S
new file mode 100644
index 000000000000..f1f40223b5c3
--- /dev/null
+++ b/kernel/bpf/preload/bpf_preload_umd_blob.S
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+	.section .init.rodata, "a"
+	.global bpf_preload_umd_start
+bpf_preload_umd_start:
+	.incbin "kernel/bpf/preload/bpf_preload_umd"
+	.global bpf_preload_umd_end
+bpf_preload_umd_end:
diff --git a/kernel/bpf/preload/iterators/bpf_preload_common.h b/kernel/bpf/preload/iterators/bpf_preload_common.h
new file mode 100644
index 000000000000..8464d1a48c05
--- /dev/null
+++ b/kernel/bpf/preload/iterators/bpf_preload_common.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BPF_PRELOAD_COMMON_H
+#define _BPF_PRELOAD_COMMON_H
+
+#define BPF_PRELOAD_START 0x5555
+#define BPF_PRELOAD_END 0xAAAA
+
+struct bpf_preload_info {
+	char link_name[16];
+	int link_id;
+};
+
+#endif
diff --git a/kernel/bpf/preload/iterators/iterators.c b/kernel/bpf/preload/iterators/iterators.c
new file mode 100644
index 000000000000..b7ff87939172
--- /dev/null
+++ b/kernel/bpf/preload/iterators/iterators.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Facebook */
+#include <argp.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/resource.h>
+#include <bpf/libbpf.h>
+#include <bpf/bpf.h>
+#include <sys/mount.h>
+#include "iterators.skel.h"
+#include "bpf_preload_common.h"
+
+int to_kernel = -1;
+int from_kernel = 0;
+
+static int send_link_to_kernel(struct bpf_link *link, const char *link_name)
+{
+	struct bpf_preload_info obj = {};
+	struct bpf_link_info info = {};
+	__u32 info_len = sizeof(info);
+	int err;
+
+	err = bpf_obj_get_info_by_fd(bpf_link__fd(link), &info, &info_len);
+	if (err)
+		return err;
+	obj.link_id = info.id;
+	if (strlen(link_name) >= sizeof(obj.link_name))
+		return -E2BIG;
+	strcpy(obj.link_name, link_name);
+	if (write(to_kernel, &obj, sizeof(obj)) != sizeof(obj))
+		return -EPIPE;
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	struct rlimit rlim = { RLIM_INFINITY, RLIM_INFINITY };
+	struct iterators_bpf *skel;
+	int err, magic;
+	int debug_fd;
+
+	debug_fd = open("/dev/console", O_WRONLY | O_NOCTTY | O_CLOEXEC);
+	if (debug_fd < 0)
+		return 1;
+	to_kernel = dup(1);
+	close(1);
+	dup(debug_fd);
+	/* now stdin and stderr point to /dev/console */
+
+	read(from_kernel, &magic, sizeof(magic));
+	if (magic != BPF_PRELOAD_START) {
+		printf("bad start magic %d\n", magic);
+		return 1;
+	}
+	setrlimit(RLIMIT_MEMLOCK, &rlim);
+	/* libbpf opens BPF object and loads it into the kernel */
+	skel = iterators_bpf__open_and_load();
+	if (!skel) {
+		/* iterators.skel.h is little endian.
+		 * libbpf doesn't support automatic little->big conversion
+		 * of BPF bytecode yet.
+		 * The program load will fail in such case.
+		 */
+		printf("Failed load could be due to wrong endianness\n");
+		return 1;
+	}
+	err = iterators_bpf__attach(skel);
+	if (err)
+		goto cleanup;
+
+	/* send two bpf_link IDs with names to the kernel */
+	err = send_link_to_kernel(skel->links.dump_bpf_map, "maps.debug");
+	if (err)
+		goto cleanup;
+	err = send_link_to_kernel(skel->links.dump_bpf_prog, "progs.debug");
+	if (err)
+		goto cleanup;
+
+	/* The kernel will proceed with pinnging the links in bpffs.
+	 * UMD will wait on read from pipe.
+	 */
+	read(from_kernel, &magic, sizeof(magic));
+	if (magic != BPF_PRELOAD_END) {
+		printf("bad final magic %d\n", magic);
+		err = -EINVAL;
+	}
+cleanup:
+	iterators_bpf__destroy(skel);
+
+	return err != 0;
+}
-- 
cgit v1.2.3


From 6b0a249a301e2af9adda84adbced3a2988248b95 Mon Sep 17 00:00:00 2001
From: Yonghong Song <yhs@fb.com>
Date: Fri, 21 Aug 2020 11:44:18 -0700
Subject: bpf: Implement link_query for bpf iterators

This patch implemented bpf_link callback functions
show_fdinfo and fill_link_info to support link_query
interface.

The general interface for show_fdinfo and fill_link_info
will print/fill the target_name. Each targets can
register show_fdinfo and fill_link_info callbacks
to print/fill more target specific information.

For example, the below is a fdinfo result for a bpf
task iterator.
  $ cat /proc/1749/fdinfo/7
  pos:    0
  flags:  02000000
  mnt_id: 14
  link_type:      iter
  link_id:        11
  prog_tag:       990e1f8152f7e54f
  prog_id:        59
  target_name:    task

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200821184418.574122-1-yhs@fb.com
---
 kernel/bpf/bpf_iter.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

(limited to 'kernel')

diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index b6715964b685..aeec7e174188 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -377,10 +377,68 @@ out_unlock:
 	return ret;
 }
 
+static void bpf_iter_link_show_fdinfo(const struct bpf_link *link,
+				      struct seq_file *seq)
+{
+	struct bpf_iter_link *iter_link =
+		container_of(link, struct bpf_iter_link, link);
+	bpf_iter_show_fdinfo_t show_fdinfo;
+
+	seq_printf(seq,
+		   "target_name:\t%s\n",
+		   iter_link->tinfo->reg_info->target);
+
+	show_fdinfo = iter_link->tinfo->reg_info->show_fdinfo;
+	if (show_fdinfo)
+		show_fdinfo(&iter_link->aux, seq);
+}
+
+static int bpf_iter_link_fill_link_info(const struct bpf_link *link,
+					struct bpf_link_info *info)
+{
+	struct bpf_iter_link *iter_link =
+		container_of(link, struct bpf_iter_link, link);
+	char __user *ubuf = u64_to_user_ptr(info->iter.target_name);
+	bpf_iter_fill_link_info_t fill_link_info;
+	u32 ulen = info->iter.target_name_len;
+	const char *target_name;
+	u32 target_len;
+
+	if (!ulen ^ !ubuf)
+		return -EINVAL;
+
+	target_name = iter_link->tinfo->reg_info->target;
+	target_len =  strlen(target_name);
+	info->iter.target_name_len = target_len + 1;
+
+	if (ubuf) {
+		if (ulen >= target_len + 1) {
+			if (copy_to_user(ubuf, target_name, target_len + 1))
+				return -EFAULT;
+		} else {
+			char zero = '\0';
+
+			if (copy_to_user(ubuf, target_name, ulen - 1))
+				return -EFAULT;
+			if (put_user(zero, ubuf + ulen - 1))
+				return -EFAULT;
+			return -ENOSPC;
+		}
+	}
+
+	fill_link_info = iter_link->tinfo->reg_info->fill_link_info;
+	if (fill_link_info)
+		return fill_link_info(&iter_link->aux, info);
+
+	return 0;
+}
+
 static const struct bpf_link_ops bpf_iter_link_lops = {
 	.release = bpf_iter_link_release,
 	.dealloc = bpf_iter_link_dealloc,
 	.update_prog = bpf_iter_link_replace,
+	.show_fdinfo = bpf_iter_link_show_fdinfo,
+	.fill_link_info = bpf_iter_link_fill_link_info,
 };
 
 bool bpf_link_is_iter(struct bpf_link *link)
-- 
cgit v1.2.3


From b76f22269028fb252727a696084c70494d80a52c Mon Sep 17 00:00:00 2001
From: Yonghong Song <yhs@fb.com>
Date: Fri, 21 Aug 2020 11:44:19 -0700
Subject: bpf: Implement link_query callbacks in map element iterators

For bpf_map_elem and bpf_sk_local_storage bpf iterators,
additional map_id should be shown for fdinfo and
userspace query. For example, the following is for
a bpf_map_elem iterator.
  $ cat /proc/1753/fdinfo/9
  pos:    0
  flags:  02000000
  mnt_id: 14
  link_type:      iter
  link_id:        34
  prog_tag:       104be6d3fe45e6aa
  prog_id:        173
  target_name:    bpf_map_elem
  map_id: 127

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200821184419.574240-1-yhs@fb.com
---
 kernel/bpf/map_iter.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

(limited to 'kernel')

diff --git a/kernel/bpf/map_iter.c b/kernel/bpf/map_iter.c
index af86048e5afd..6a9542af4212 100644
--- a/kernel/bpf/map_iter.c
+++ b/kernel/bpf/map_iter.c
@@ -149,6 +149,19 @@ static void bpf_iter_detach_map(struct bpf_iter_aux_info *aux)
 	bpf_map_put_with_uref(aux->map);
 }
 
+void bpf_iter_map_show_fdinfo(const struct bpf_iter_aux_info *aux,
+			      struct seq_file *seq)
+{
+	seq_printf(seq, "map_id:\t%u\n", aux->map->id);
+}
+
+int bpf_iter_map_fill_link_info(const struct bpf_iter_aux_info *aux,
+				struct bpf_link_info *info)
+{
+	info->iter.map.map_id = aux->map->id;
+	return 0;
+}
+
 DEFINE_BPF_ITER_FUNC(bpf_map_elem, struct bpf_iter_meta *meta,
 		     struct bpf_map *map, void *key, void *value)
 
@@ -156,6 +169,8 @@ static const struct bpf_iter_reg bpf_map_elem_reg_info = {
 	.target			= "bpf_map_elem",
 	.attach_target		= bpf_iter_attach_map,
 	.detach_target		= bpf_iter_detach_map,
+	.show_fdinfo		= bpf_iter_map_show_fdinfo,
+	.fill_link_info		= bpf_iter_map_fill_link_info,
 	.ctx_arg_info_size	= 2,
 	.ctx_arg_info		= {
 		{ offsetof(struct bpf_iter__bpf_map_elem, key),
-- 
cgit v1.2.3


From 13b79d3ffbb8add9e2a6d604db2b49f241b97303 Mon Sep 17 00:00:00 2001
From: Lorenz Bauer <lmb@cloudflare.com>
Date: Fri, 21 Aug 2020 11:29:45 +0100
Subject: bpf: sockmap: Call sock_map_update_elem directly

Don't go via map->ops to call sock_map_update_elem, since we know
what function to call in bpf_map_update_value. Since we currently
don't allow calling map_update_elem from BPF context, we can remove
ops->map_update_elem and rename the function to sock_map_update_elem_sys.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200821102948.21918-4-lmb@cloudflare.com
---
 kernel/bpf/syscall.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

(limited to 'kernel')

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 689d736b6904..b46e973faee9 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -157,10 +157,11 @@ static int bpf_map_update_value(struct bpf_map *map, struct fd f, void *key,
 	if (bpf_map_is_dev_bound(map)) {
 		return bpf_map_offload_update_elem(map, key, value, flags);
 	} else if (map->map_type == BPF_MAP_TYPE_CPUMAP ||
-		   map->map_type == BPF_MAP_TYPE_SOCKHASH ||
-		   map->map_type == BPF_MAP_TYPE_SOCKMAP ||
 		   map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
 		return map->ops->map_update_elem(map, key, value, flags);
+	} else if (map->map_type == BPF_MAP_TYPE_SOCKHASH ||
+		   map->map_type == BPF_MAP_TYPE_SOCKMAP) {
+		return sock_map_update_elem_sys(map, key, value, flags);
 	} else if (IS_FD_PROG_ARRAY(map)) {
 		return bpf_fd_array_map_update_elem(map, f.file, key, value,
 						    flags);
-- 
cgit v1.2.3


From 912f442cfb1fc695510e055bdae5f4a88e4de6b8 Mon Sep 17 00:00:00 2001
From: Lorenz Bauer <lmb@cloudflare.com>
Date: Fri, 21 Aug 2020 11:29:46 +0100
Subject: bpf: Override the meaning of ARG_PTR_TO_MAP_VALUE for sockmap and
 sockhash

The verifier assumes that map values are simple blobs of memory, and
therefore treats ARG_PTR_TO_MAP_VALUE, etc. as such. However, there are
map types where this isn't true. For example, sockmap and sockhash store
sockets. In general this isn't a big problem: we can just
write helpers that explicitly requests PTR_TO_SOCKET instead of
ARG_PTR_TO_MAP_VALUE.

The one exception are the standard map helpers like map_update_elem,
map_lookup_elem, etc. Here it would be nice we could overload the
function prototype for different kinds of maps. Unfortunately, this
isn't entirely straight forward:
We only know the type of the map once we have resolved meta->map_ptr
in check_func_arg. This means we can't swap out the prototype
in check_helper_call until we're half way through the function.

Instead, modify check_func_arg to treat ARG_PTR_TO_MAP_VALUE to
mean "the native type for the map" instead of "pointer to memory"
for sockmap and sockhash. This means we don't have to modify the
function prototype at all

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200821102948.21918-5-lmb@cloudflare.com
---
 kernel/bpf/verifier.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

(limited to 'kernel')

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index ef938f17b944..f8629bf848fe 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3872,6 +3872,33 @@ static int int_ptr_type_to_size(enum bpf_arg_type type)
 	return -EINVAL;
 }
 
+static int resolve_map_arg_type(struct bpf_verifier_env *env,
+				 const struct bpf_call_arg_meta *meta,
+				 enum bpf_arg_type *arg_type)
+{
+	if (!meta->map_ptr) {
+		/* kernel subsystem misconfigured verifier */
+		verbose(env, "invalid map_ptr to access map->type\n");
+		return -EACCES;
+	}
+
+	switch (meta->map_ptr->map_type) {
+	case BPF_MAP_TYPE_SOCKMAP:
+	case BPF_MAP_TYPE_SOCKHASH:
+		if (*arg_type == ARG_PTR_TO_MAP_VALUE) {
+			*arg_type = ARG_PTR_TO_SOCKET;
+		} else {
+			verbose(env, "invalid arg_type for sockmap/sockhash\n");
+			return -EINVAL;
+		}
+		break;
+
+	default:
+		break;
+	}
+	return 0;
+}
+
 static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
 			  struct bpf_call_arg_meta *meta,
 			  const struct bpf_func_proto *fn)
@@ -3904,6 +3931,14 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
 		return -EACCES;
 	}
 
+	if (arg_type == ARG_PTR_TO_MAP_VALUE ||
+	    arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE ||
+	    arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL) {
+		err = resolve_map_arg_type(env, meta, &arg_type);
+		if (err)
+			return err;
+	}
+
 	if (arg_type == ARG_PTR_TO_MAP_KEY ||
 	    arg_type == ARG_PTR_TO_MAP_VALUE ||
 	    arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE ||
-- 
cgit v1.2.3


From 0126240f448d5bba29d0d1593aa527d3bf67b916 Mon Sep 17 00:00:00 2001
From: Lorenz Bauer <lmb@cloudflare.com>
Date: Fri, 21 Aug 2020 11:29:47 +0100
Subject: bpf: sockmap: Allow update from BPF

Allow calling bpf_map_update_elem on sockmap and sockhash from a BPF
context. The synchronization required for this is a bit fiddly: we
need to prevent the socket from changing its state while we add it
to the sockmap, since we rely on getting a callback via
sk_prot->unhash. However, we can't just lock_sock like in
sock_map_sk_acquire because that might sleep. So instead we disable
softirq processing and use bh_lock_sock to prevent further
modification.

Yet, this is still not enough. BPF can be called in contexts where
the current CPU might have locked a socket. If the BPF can get
a hold of such a socket, inserting it into a sockmap would lead to
a deadlock. One straight forward example are sock_ops programs that
have ctx->sk, but the same problem exists for kprobes, etc.
We deal with this by allowing sockmap updates only from known safe
contexts. Improper usage is rejected by the verifier.

I've audited the enabled contexts to make sure they can't run in
a locked context. It's possible that CGROUP_SKB and others are
safe as well, but the auditing here is much more difficult. In
any case, we can extend the safe contexts when the need arises.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200821102948.21918-6-lmb@cloudflare.com
---
 kernel/bpf/verifier.c | 38 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)

(limited to 'kernel')

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index f8629bf848fe..dd24503ab3d3 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -4178,6 +4178,38 @@ err_type:
 	return -EACCES;
 }
 
+static bool may_update_sockmap(struct bpf_verifier_env *env, int func_id)
+{
+	enum bpf_attach_type eatype = env->prog->expected_attach_type;
+	enum bpf_prog_type type = env->prog->type;
+
+	if (func_id != BPF_FUNC_map_update_elem)
+		return false;
+
+	/* It's not possible to get access to a locked struct sock in these
+	 * contexts, so updating is safe.
+	 */
+	switch (type) {
+	case BPF_PROG_TYPE_TRACING:
+		if (eatype == BPF_TRACE_ITER)
+			return true;
+		break;
+	case BPF_PROG_TYPE_SOCKET_FILTER:
+	case BPF_PROG_TYPE_SCHED_CLS:
+	case BPF_PROG_TYPE_SCHED_ACT:
+	case BPF_PROG_TYPE_XDP:
+	case BPF_PROG_TYPE_SK_REUSEPORT:
+	case BPF_PROG_TYPE_FLOW_DISSECTOR:
+	case BPF_PROG_TYPE_SK_LOOKUP:
+		return true;
+	default:
+		break;
+	}
+
+	verbose(env, "cannot update sockmap in this context\n");
+	return false;
+}
+
 static int check_map_func_compatibility(struct bpf_verifier_env *env,
 					struct bpf_map *map, int func_id)
 {
@@ -4249,7 +4281,8 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
 		    func_id != BPF_FUNC_map_delete_elem &&
 		    func_id != BPF_FUNC_msg_redirect_map &&
 		    func_id != BPF_FUNC_sk_select_reuseport &&
-		    func_id != BPF_FUNC_map_lookup_elem)
+		    func_id != BPF_FUNC_map_lookup_elem &&
+		    !may_update_sockmap(env, func_id))
 			goto error;
 		break;
 	case BPF_MAP_TYPE_SOCKHASH:
@@ -4258,7 +4291,8 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
 		    func_id != BPF_FUNC_map_delete_elem &&
 		    func_id != BPF_FUNC_msg_redirect_hash &&
 		    func_id != BPF_FUNC_sk_select_reuseport &&
-		    func_id != BPF_FUNC_map_lookup_elem)
+		    func_id != BPF_FUNC_map_lookup_elem &&
+		    !may_update_sockmap(env, func_id))
 			goto error;
 		break;
 	case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
-- 
cgit v1.2.3


From 450af8d0f6be2e7dd2a528a3fb054bb726bf1747 Mon Sep 17 00:00:00 2001
From: KP Singh <kpsingh@google.com>
Date: Tue, 25 Aug 2020 20:29:16 +0200
Subject: bpf: Split bpf_local_storage to bpf_sk_storage

A purely mechanical change:

	bpf_sk_storage.c = bpf_sk_storage.c + bpf_local_storage.c
	bpf_sk_storage.h = bpf_sk_storage.h + bpf_local_storage.h

Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200825182919.1118197-5-kpsingh@chromium.org
---
 kernel/bpf/Makefile            |   1 +
 kernel/bpf/bpf_local_storage.c | 600 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 601 insertions(+)
 create mode 100644 kernel/bpf/bpf_local_storage.c

(limited to 'ke