BPF Archive on lore.kernel.org
 help / color / Atom feed
From: Jiri Olsa <jolsa@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>
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>, Andrii Nakryiko <andriin@fb.com>,
	Brendan Gregg <bgregg@netflix.com>,
	Florent Revest <revest@chromium.org>,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: [PATCH 08/11] bpf: Add BTF whitelist support
Date: Tue, 16 Jun 2020 12:05:09 +0200
Message-ID: <20200616100512.2168860-9-jolsa@kernel.org> (raw)
In-Reply-To: <20200616100512.2168860-1-jolsa@kernel.org>

Adding support to define 'whitelist' of BTF IDs, which is
also sorted.

Following defines sorted list of BTF IDs that is accessible
within kernel code as btf_whitelist_d_path and its count is
in btf_whitelist_d_path_cnt variable.

  extern int btf_whitelist_d_path[];
  extern int btf_whitelist_d_path_cnt;

  BTF_WHITELIST_ENTRY(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_WHITELIST_END(btf_whitelist_d_path)

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 include/linux/bpf.h   |  3 +++
 kernel/bpf/btf.c      | 13 +++++++++++++
 kernel/bpf/btf_ids.h  | 38 ++++++++++++++++++++++++++++++++++++++
 kernel/bpf/verifier.c |  5 +++++
 4 files changed, 59 insertions(+)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index e98c113a5d27..a94e85c2ec50 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -283,6 +283,7 @@ struct bpf_func_proto {
 		enum bpf_arg_type arg_type[5];
 	};
 	int *btf_id; /* BTF ids of arguments */
+	bool (*allowed)(const struct bpf_prog *prog);
 };
 
 /* bpf_context is intentionally undefined structure. Pointer to bpf_context is
@@ -1745,6 +1746,8 @@ enum bpf_text_poke_type {
 int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
 		       void *addr1, void *addr2);
 
+bool btf_whitelist_search(int id, int list[], int cnt);
+
 extern int bpf_skb_output_btf_ids[];
 extern int bpf_seq_printf_btf_ids[];
 extern int bpf_seq_write_btf_ids[];
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 6924180a19c4..feda74d232c5 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -20,6 +20,7 @@
 #include <linux/btf.h>
 #include <linux/skmsg.h>
 #include <linux/perf_event.h>
+#include <linux/bsearch.h>
 #include <net/sock.h>
 
 /* BTF (BPF Type Format) is the meta data format which describes
@@ -4669,3 +4670,15 @@ 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_whitelist_search(int id, int list[], int cnt)
+{
+	return bsearch(&id, list, cnt, sizeof(int), btf_id_cmp_func) != NULL;
+}
diff --git a/kernel/bpf/btf_ids.h b/kernel/bpf/btf_ids.h
index 68aa5c38a37f..a90c09faa515 100644
--- a/kernel/bpf/btf_ids.h
+++ b/kernel/bpf/btf_ids.h
@@ -67,4 +67,42 @@ asm(							\
 #name ":;                                      \n"	\
 ".popsection;                                  \n");
 
+
+/*
+ * The BTF_WHITELIST_ENTRY/END macros pair defines sorted
+ * list of BTF IDs plus its members count, with following
+ * layout:
+ *
+ * BTF_WHITELIST_ENTRY(list2)
+ * BTF_ID(type1, name1)
+ * BTF_ID(type2, name2)
+ * BTF_WHITELIST_END(list)
+ *
+ * __BTF_ID__sort__list:
+ * list2_cnt:
+ * .zero 4
+ * list2:
+ * __BTF_ID__type1__name1__3:
+ * .zero 4
+ * __BTF_ID__type2__name2__4:
+ * .zero 4
+ *
+ */
+#define BTF_WHITELIST_ENTRY(name)			\
+asm(							\
+".pushsection " SECTION ",\"a\";               \n"	\
+".global __BTF_ID__sort__" #name ";            \n"	\
+"__BTF_ID__sort__" #name ":;                   \n"	\
+".global " #name "_cnt;                        \n"	\
+#name "_cnt:;                                  \n"	\
+".zero 4                                       \n"	\
+".popsection;                                  \n");	\
+BTF_ID_LIST(name)
+
+#define BTF_WHITELIST_END(name)				\
+asm(							\
+".pushsection " SECTION ",\"a\";              \n"	\
+".size __BTF_ID__sort__" #name ", .-" #name " \n"	\
+".popsection;                                 \n");
+
 #endif
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index bee3da2cd945..5a9a6fd72907 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -4633,6 +4633,11 @@ 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) {
-- 
2.25.4


  parent reply index

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-16 10:05 [PATCHv3 0/9] bpf: Add d_path helper Jiri Olsa
2020-06-16 10:05 ` [PATCH 01/11] bpf: Add btfid tool to resolve BTF IDs in ELF object Jiri Olsa
2020-06-19  0:38   ` Andrii Nakryiko
2020-06-19 13:03     ` Jiri Olsa
2020-06-19 18:12       ` Andrii Nakryiko
2020-06-22  8:59         ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 02/11] bpf: Compile btfid tool at kernel compilation start Jiri Olsa
2020-06-18 20:40   ` John Fastabend
2020-06-18 21:17     ` John Fastabend
2020-06-19 13:23     ` Jiri Olsa
2020-06-19  0:40   ` Andrii Nakryiko
2020-06-19  0:47     ` Arnaldo Carvalho de Melo
2020-06-19  2:08       ` Alexei Starovoitov
2020-06-19  3:51         ` Andrii Nakryiko
2020-06-16 10:05 ` [PATCH 03/11] bpf: Add btf_ids object Jiri Olsa
2020-06-19  0:56   ` Andrii Nakryiko
2020-06-19  1:06     ` Andrii Nakryiko
2020-06-19 13:16       ` Jiri Olsa
2020-06-19 13:13     ` Jiri Olsa
2020-06-19 18:15       ` Andrii Nakryiko
2020-06-19  1:02   ` Andrii Nakryiko
2020-06-19 13:05     ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 04/11] bpf: Resolve BTF IDs in vmlinux image Jiri Olsa
2020-06-16 10:05 ` [PATCH 05/11] bpf: Remove btf_id helpers resolving Jiri Olsa
2020-06-19  1:10   ` Andrii Nakryiko
2020-06-19 13:18     ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 06/11] bpf: Do not pass enum bpf_access_type to btf_struct_access Jiri Olsa
2020-06-19  3:58   ` Andrii Nakryiko
2020-06-19 13:23     ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 07/11] bpf: Allow nested BTF object to be refferenced by BTF object + offset Jiri Olsa
2020-06-16 10:05 ` Jiri Olsa [this message]
2020-06-19  4:29   ` [PATCH 08/11] bpf: Add BTF whitelist support Andrii Nakryiko
2020-06-19 13:29     ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 09/11] bpf: Add d_path helper Jiri Olsa
2020-06-19  4:35   ` Andrii Nakryiko
2020-06-19 13:31     ` Jiri Olsa
2020-06-19 18:25       ` Andrii Nakryiko
2020-06-22  9:02         ` Jiri Olsa
2020-06-22 19:18           ` Andrii Nakryiko
2020-06-23 10:02             ` Jiri Olsa
2020-06-23 18:58               ` Andrii Nakryiko
2020-06-23 20:14                 ` Jiri Olsa
2020-06-23 20:17                   ` Andrii Nakryiko
2020-06-16 10:05 ` [PATCH 10/11] selftests/bpf: Add verifier test for " Jiri Olsa
2020-06-19  4:38   ` Andrii Nakryiko
2020-06-19 13:32     ` Jiri Olsa
2020-06-16 10:05 ` [PATCH 11/11] selftests/bpf: Add " Jiri Olsa
2020-06-19  4:44   ` Andrii Nakryiko
2020-06-19 13:34     ` Jiri Olsa
2020-06-18 20:57 ` [PATCHv3 0/9] bpf: Add " John Fastabend
2020-06-19 12:35   ` Jiri Olsa

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200616100512.2168860-9-jolsa@kernel.org \
    --to=jolsa@kernel.org \
    --cc=andriin@fb.com \
    --cc=ast@kernel.org \
    --cc=bgregg@netflix.com \
    --cc=bpf@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=davem@redhat.com \
    --cc=ethercflow@gmail.com \
    --cc=john.fastabend@gmail.com \
    --cc=kafai@fb.com \
    --cc=kpsingh@chromium.org \
    --cc=netdev@vger.kernel.org \
    --cc=revest@chromium.org \
    --cc=songliubraving@fb.com \
    --cc=viro@zeniv.linux.org.uk \
    --cc=yhs@fb.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

BPF Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/bpf/0 bpf/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 bpf bpf/ https://lore.kernel.org/bpf \
		bpf@vger.kernel.org
	public-inbox-index bpf

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.bpf


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git