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Message-Id: <20200722211223.1055107-9-jolsa@kernel.org>
Date: Wed, 22 Jul 2020 23:12:18 +0200
From: Jiri Olsa <jolsa@...nel.org>
To: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Andrii Nakryiko <andriin@...com>
Cc: netdev@...r.kernel.org, bpf@...r.kernel.org,
Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
Martin KaFai Lau <kafai@...com>,
David Miller <davem@...hat.com>,
John Fastabend <john.fastabend@...il.com>,
Wenbo Zhang <ethercflow@...il.com>,
KP Singh <kpsingh@...omium.org>,
Brendan Gregg <bgregg@...flix.com>,
Florent Revest <revest@...omium.org>,
Al Viro <viro@...iv.linux.org.uk>
Subject: [PATCH v8 bpf-next 08/13] bpf: Add BTF_SET_START/END macros
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@...nel.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
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