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 [thread overview]
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
next prev parent reply other threads:[~2020-06-16 10:06 UTC|newest]
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
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