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From: Jiri Olsa <jolsa@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andriin@fb.com>
Cc: netdev@vger.kernel.org, bpf@vger.kernel.org,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	Martin KaFai Lau <kafai@fb.com>, David Miller <davem@redhat.com>,
	John Fastabend <john.fastabend@gmail.com>,
	Wenbo Zhang <ethercflow@gmail.com>,
	KP Singh <kpsingh@chromium.org>,
	Brendan Gregg <bgregg@netflix.com>,
	Florent Revest <revest@chromium.org>,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: [PATCH v8 bpf-next 08/13] bpf: Add BTF_SET_START/END macros
Date: Wed, 22 Jul 2020 23:12:18 +0200
Message-ID: <20200722211223.1055107-9-jolsa@kernel.org> (raw)
In-Reply-To: <20200722211223.1055107-1-jolsa@kernel.org>

Adding support to define sorted set of BTF ID values.

Following defines sorted set of BTF ID values:

  BTF_SET_START(btf_whitelist_d_path)
  BTF_ID(func, vfs_truncate)
  BTF_ID(func, vfs_fallocate)
  BTF_ID(func, dentry_open)
  BTF_ID(func, vfs_getattr)
  BTF_ID(func, filp_close)
  BTF_SET_END(btf_whitelist_d_path)

It defines following 'struct btf_id_set' variable to access
values and count:

  struct btf_id_set btf_whitelist_d_path;

Adding 'allowed' callback to struct bpf_func_proto, to allow
verifier the check on allowed callers.

Adding btf_id_set_contains function, which will be used by
allowed callbacks to verify the caller's BTF ID value is
within allowed set.

Also removing extra '\' in __BTF_ID_LIST macro.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 include/linux/bpf.h           |  4 ++++
 include/linux/btf_ids.h       | 43 ++++++++++++++++++++++++++++++++++-
 kernel/bpf/btf.c              | 14 ++++++++++++
 kernel/bpf/verifier.c         |  5 ++++
 tools/include/linux/btf_ids.h | 43 ++++++++++++++++++++++++++++++++++-
 5 files changed, 107 insertions(+), 2 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index c981e258fed3..e5d81c31ed8e 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -295,6 +295,7 @@ struct bpf_func_proto {
 						    * for this argument.
 						    */
 	int *ret_btf_id; /* return value btf_id */
+	bool (*allowed)(const struct bpf_prog *prog);
 };
 
 /* bpf_context is intentionally undefined structure. Pointer to bpf_context is
@@ -1787,4 +1788,7 @@ enum bpf_text_poke_type {
 int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
 		       void *addr1, void *addr2);
 
+struct btf_id_set;
+bool btf_id_set_contains(struct btf_id_set *set, u32 id);
+
 #endif /* _LINUX_BPF_H */
diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 4867d549e3c1..840c3e63cc13 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -3,6 +3,11 @@
 #ifndef _LINUX_BTF_IDS_H
 #define _LINUX_BTF_IDS_H
 
+struct btf_id_set {
+	u32 cnt;
+	u32 ids[];
+};
+
 #ifdef CONFIG_DEBUG_INFO_BTF
 
 #include <linux/compiler.h> /* for __PASTE */
@@ -62,7 +67,7 @@ asm(							\
 ".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
 "." #scope " " #name ";                        \n"	\
 #name ":;                                      \n"	\
-".popsection;                                  \n");	\
+".popsection;                                  \n");
 
 #define BTF_ID_LIST(name)				\
 __BTF_ID_LIST(name, local)				\
@@ -88,12 +93,48 @@ asm(							\
 ".zero 4                                       \n"	\
 ".popsection;                                  \n");
 
+/*
+ * The BTF_SET_START/END macros pair defines sorted list of
+ * BTF IDs plus its members count, with following layout:
+ *
+ * BTF_SET_START(list)
+ * BTF_ID(type1, name1)
+ * BTF_ID(type2, name2)
+ * BTF_SET_END(list)
+ *
+ * __BTF_ID__set__list:
+ * .zero 4
+ * list:
+ * __BTF_ID__type1__name1__3:
+ * .zero 4
+ * __BTF_ID__type2__name2__4:
+ * .zero 4
+ *
+ */
+#define BTF_SET_START(name)				\
+__BTF_ID_LIST(name, local)				\
+asm(							\
+".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
+".local __BTF_ID__set__" #name ";              \n"	\
+"__BTF_ID__set__" #name ":;                    \n"	\
+".zero 4                                       \n"	\
+".popsection;                                  \n");
+
+#define BTF_SET_END(name)				\
+asm(							\
+".pushsection " BTF_IDS_SECTION ",\"a\";      \n"	\
+".size __BTF_ID__set__" #name ", .-" #name "  \n"	\
+".popsection;                                 \n");	\
+extern struct btf_id_set name;
+
 #else
 
 #define BTF_ID_LIST(name) static u32 name[5];
 #define BTF_ID(prefix, name)
 #define BTF_ID_UNUSED
 #define BTF_ID_LIST_GLOBAL(name) u32 name[1];
+#define BTF_SET_START(name) static struct btf_id_set name = { 0 };
+#define BTF_SET_END(name)
 
 #endif /* CONFIG_DEBUG_INFO_BTF */
 
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 562d4453fad3..06714cdda0a9 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -21,6 +21,8 @@
 #include <linux/btf_ids.h>
 #include <linux/skmsg.h>
 #include <linux/perf_event.h>
+#include <linux/bsearch.h>
+#include <linux/btf_ids.h>
 #include <net/sock.h>
 
 /* BTF (BPF Type Format) is the meta data format which describes
@@ -4740,3 +4742,15 @@ u32 btf_id(const struct btf *btf)
 {
 	return btf->id;
 }
+
+static int btf_id_cmp_func(const void *a, const void *b)
+{
+	const int *pa = a, *pb = b;
+
+	return *pa - *pb;
+}
+
+bool btf_id_set_contains(struct btf_id_set *set, u32 id)
+{
+	return bsearch(&id, set->ids, set->cnt, sizeof(int), btf_id_cmp_func) != NULL;
+}
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 39922fa07154..49f728c696a9 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -4706,6 +4706,11 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
 		return -EINVAL;
 	}
 
+	if (fn->allowed && !fn->allowed(env->prog)) {
+		verbose(env, "helper call is not allowed in probe\n");
+		return -EINVAL;
+	}
+
 	/* With LD_ABS/IND some JITs save/restore skb from r1. */
 	changes_data = bpf_helper_changes_pkt_data(fn->func);
 	if (changes_data && fn->arg1_type != ARG_PTR_TO_CTX) {
diff --git a/tools/include/linux/btf_ids.h b/tools/include/linux/btf_ids.h
index 4867d549e3c1..840c3e63cc13 100644
--- a/tools/include/linux/btf_ids.h
+++ b/tools/include/linux/btf_ids.h
@@ -3,6 +3,11 @@
 #ifndef _LINUX_BTF_IDS_H
 #define _LINUX_BTF_IDS_H
 
+struct btf_id_set {
+	u32 cnt;
+	u32 ids[];
+};
+
 #ifdef CONFIG_DEBUG_INFO_BTF
 
 #include <linux/compiler.h> /* for __PASTE */
@@ -62,7 +67,7 @@ asm(							\
 ".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
 "." #scope " " #name ";                        \n"	\
 #name ":;                                      \n"	\
-".popsection;                                  \n");	\
+".popsection;                                  \n");
 
 #define BTF_ID_LIST(name)				\
 __BTF_ID_LIST(name, local)				\
@@ -88,12 +93,48 @@ asm(							\
 ".zero 4                                       \n"	\
 ".popsection;                                  \n");
 
+/*
+ * The BTF_SET_START/END macros pair defines sorted list of
+ * BTF IDs plus its members count, with following layout:
+ *
+ * BTF_SET_START(list)
+ * BTF_ID(type1, name1)
+ * BTF_ID(type2, name2)
+ * BTF_SET_END(list)
+ *
+ * __BTF_ID__set__list:
+ * .zero 4
+ * list:
+ * __BTF_ID__type1__name1__3:
+ * .zero 4
+ * __BTF_ID__type2__name2__4:
+ * .zero 4
+ *
+ */
+#define BTF_SET_START(name)				\
+__BTF_ID_LIST(name, local)				\
+asm(							\
+".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
+".local __BTF_ID__set__" #name ";              \n"	\
+"__BTF_ID__set__" #name ":;                    \n"	\
+".zero 4                                       \n"	\
+".popsection;                                  \n");
+
+#define BTF_SET_END(name)				\
+asm(							\
+".pushsection " BTF_IDS_SECTION ",\"a\";      \n"	\
+".size __BTF_ID__set__" #name ", .-" #name "  \n"	\
+".popsection;                                 \n");	\
+extern struct btf_id_set name;
+
 #else
 
 #define BTF_ID_LIST(name) static u32 name[5];
 #define BTF_ID(prefix, name)
 #define BTF_ID_UNUSED
 #define BTF_ID_LIST_GLOBAL(name) u32 name[1];
+#define BTF_SET_START(name) static struct btf_id_set name = { 0 };
+#define BTF_SET_END(name)
 
 #endif /* CONFIG_DEBUG_INFO_BTF */
 
-- 
2.25.4


  parent reply index

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-22 21:12 [PATCH v8 bpf-next 00/13] bpf: Add d_path helper Jiri Olsa
2020-07-22 21:12 ` [PATCH v8 bpf-next 01/13] selftests/bpf: Fix resolve_btfids test Jiri Olsa
2020-07-28 20:27   ` Andrii Nakryiko
2020-07-29 20:06     ` Jiri Olsa
2020-07-29 21:38       ` Andrii Nakryiko
2020-07-22 21:12 ` [PATCH v8 bpf-next 02/13] tools resolve_btfids: Add support for set symbols Jiri Olsa
2020-07-28  0:53   ` Andrii Nakryiko
2020-07-28  9:35     ` Jiri Olsa
2020-07-22 21:12 ` [PATCH v8 bpf-next 03/13] bpf: Move btf_resolve_size into __btf_resolve_size Jiri Olsa
2020-07-28 20:29   ` Andrii Nakryiko
2020-07-22 21:12 ` [PATCH v8 bpf-next 04/13] bpf: Add elem_id pointer as argument to __btf_resolve_size Jiri Olsa
2020-07-28 20:30   ` Andrii Nakryiko
2020-07-22 21:12 ` [PATCH v8 bpf-next 05/13] bpf: Add type_id " Jiri Olsa
2020-07-22 21:12 ` [PATCH v8 bpf-next 06/13] bpf: Factor btf_struct_access function Jiri Olsa
2020-07-28 23:27   ` Andrii Nakryiko
2020-07-29 15:59     ` Jiri Olsa
2020-07-22 21:12 ` [PATCH v8 bpf-next 07/13] bpf: Add btf_struct_ids_match function Jiri Olsa
2020-07-28 23:35   ` Andrii Nakryiko
2020-07-29 16:04     ` Jiri Olsa
2020-07-29 17:51       ` Andrii Nakryiko
2020-07-29 18:55         ` Jiri Olsa
2020-07-22 21:12 ` Jiri Olsa [this message]
2020-07-28 19:39   ` [PATCH v8 bpf-next 08/13] bpf: Add BTF_SET_START/END macros Andrii Nakryiko
2020-07-29 11:54     ` Jiri Olsa
2020-07-22 21:12 ` [PATCH v8 bpf-next 09/13] bpf: Add d_path helper Jiri Olsa
2020-07-28 19:47   ` Andrii Nakryiko
2020-07-29 15:54     ` Jiri Olsa
2020-07-29 20:11   ` Al Viro
2020-07-30 10:22     ` Jiri Olsa
2020-07-29 20:17   ` Al Viro
2020-07-30 10:09     ` Jiri Olsa
2020-07-22 21:12 ` [PATCH v8 bpf-next 10/13] bpf: Update .BTF_ids section in btf.rst with sets info Jiri Olsa
2020-07-22 21:12 ` [PATCH v8 bpf-next 11/13] selftests/bpf: Add verifier test for d_path helper Jiri Olsa
2020-07-28 19:49   ` Andrii Nakryiko
2020-07-22 21:12 ` [PATCH v8 bpf-next 12/13] selftests/bpf: Add " Jiri Olsa
2020-07-28 19:53   ` Andrii Nakryiko
2020-07-29 11:25     ` Jiri Olsa
2020-07-22 21:12 ` [PATCH v8 bpf-next 13/13] selftests/bpf: Add set test to resolve_btfids Jiri Olsa
2020-07-28 19:56   ` Andrii Nakryiko
2020-07-29 15:34     ` Jiri Olsa

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