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_allowlist_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_allowlist_d_path) It defines following 'struct btf_id_set' variable to access values and count: struct btf_id_set btf_allowlist_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. Added BTF_SET_START_GLOBAL macro for global sets.

Jiri Olsa committed 6 years ago

Commit eae2e831 parent faaf4a75 files · +123 −2Browse files

Unified · Split

5 files

include/linux/bpf.h +4 −0
include/linux/btf_ids.h +50 −1
kernel/bpf/btf.c +14 −0
kernel/bpf/verifier.c +5 −0
tools/include/linux/btf_ids.h +50 −1

include/linux/bpf.h+4−0

@@ -317,6 +317,7 @@ struct bpf_func_proto { · 316 unmodified lines
317	317	* for this argument.
318	318	*/
319	319	int ret_btf_id; / return value btf_id */
	320	+ bool (allowed)(const struct bpf_prog prog);
320	321	};
321	322
322	323	/* bpf_context is intentionally undefined structure. Pointer to bpf_context is
@@ -1878,4 +1879,7 @@ enum bpf_text_poke_type { · 1555 unmodified lines
1878	1879	int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
1879	1880	void addr1, void addr2);
1880	1881
	1882	+struct btf_id_set;
	1883	+bool btf_id_set_contains(struct btf_id_set *set, u32 id);
	1884	+
1881	1885	#endif /* _LINUX_BPF_H */

include/linux/btf_ids.h+50−1

@@ -3,6 +3,11 @@ · 2 unmodified lines
3	3	#ifndef _LINUX_BTF_IDS_H
4	4	#define _LINUX_BTF_IDS_H
5	5
	6	+struct btf_id_set {
	7	+ u32 cnt;
	8	+ u32 ids[];
	9	+};
	10	+
6	11	#ifdef CONFIG_DEBUG_INFO_BTF
7	12
8	13	#include <linux/compiler.h> /* for __PASTE */
@@ -62,7 +67,7 @@ asm( \ · 53 unmodified lines
62	67	".pushsection " BTF_IDS_SECTION ",\"a\"; \n" \
63	68	"." #scope " " #name "; \n" \
64	69	#name ":; \n" \
65		−".popsection; \n"); \
	70	+".popsection; \n");
66	71
67	72	#define BTF_ID_LIST(name) \
68	73	__BTF_ID_LIST(name, local) \
@@ -88,12 +93,56 @@ asm( \ · 19 unmodified lines
88	93	".zero 4 \n" \
89	94	".popsection; \n");
90	95
	96	+/*
	97	+ * The BTF_SET_START/END macros pair defines sorted list of
	98	+ * BTF IDs plus its members count, with following layout:
	99	+ *
	100	+ * BTF_SET_START(list)
	101	+ * BTF_ID(type1, name1)
	102	+ * BTF_ID(type2, name2)
	103	+ * BTF_SET_END(list)
	104	+ *
	105	+ * __BTF_ID__set__list:
	106	+ * .zero 4
	107	+ * list:
	108	+ * __BTF_ID__type1__name1__3:
	109	+ * .zero 4
	110	+ * __BTF_ID__type2__name2__4:
	111	+ * .zero 4
	112	+ *
	113	+ */
	114	+#define __BTF_SET_START(name, scope) \
	115	+asm( \
	116	+".pushsection " BTF_IDS_SECTION ",\"a\"; \n" \
	117	+"." #scope " __BTF_ID__set__" #name "; \n" \
	118	+"__BTF_ID__set__" #name ":; \n" \
	119	+".zero 4 \n" \
	120	+".popsection; \n");
	121	+
	122	+#define BTF_SET_START(name) \
	123	+__BTF_ID_LIST(name, local) \
	124	+__BTF_SET_START(name, local)
	125	+
	126	+#define BTF_SET_START_GLOBAL(name) \
	127	+__BTF_ID_LIST(name, globl) \
	128	+__BTF_SET_START(name, globl)
	129	+
	130	+#define BTF_SET_END(name) \
	131	+asm( \
	132	+".pushsection " BTF_IDS_SECTION ",\"a\"; \n" \
	133	+".size __BTF_ID__set__" #name ", .-" #name " \n" \
	134	+".popsection; \n"); \
	135	+extern struct btf_id_set name;
	136	+
91	137	#else
92	138
93	139	#define BTF_ID_LIST(name) static u32 name[5];
94	140	#define BTF_ID(prefix, name)
95	141	#define BTF_ID_UNUSED
96	142	#define BTF_ID_LIST_GLOBAL(name) u32 name[1];
	143	+#define BTF_SET_START(name) static struct btf_id_set name = { 0 };
	144	+#define BTF_SET_START_GLOBAL(name) static struct btf_id_set name = { 0 };
	145	+#define BTF_SET_END(name)
97	146
98	147	#endif /* CONFIG_DEBUG_INFO_BTF */
99	148

kernel/bpf/btf.c+14−0

@@ -21,6 +21,8 @@ · 20 unmodified lines
21	21	#include <linux/btf_ids.h>
22	22	#include <linux/skmsg.h>
23	23	#include <linux/perf_event.h>
	24	+#include <linux/bsearch.h>
	25	+#include <linux/btf_ids.h>
24	26	#include <net/sock.h>
25	27
26	28	/* BTF (BPF Type Format) is the meta data format which describes
@@ -4762,3 +4764,15 @@ u32 btf_id(const struct btf *btf) · 4735 unmodified lines
4762	4764	{
4763	4765	return btf->id;
4764	4766	}
	4767	+
	4768	+static int btf_id_cmp_func(const void a, const void b)
	4769	+{
	4770	+ const int pa = a, pb = b;
	4771	+
	4772	+ return pa - pb;
	4773	+}
	4774	+
	4775	+bool btf_id_set_contains(struct btf_id_set *set, u32 id)
	4776	+{
	4777	+ return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL;
	4778	+}

kernel/bpf/verifier.c+5−0

@@ -4859,6 +4859,11 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn · 4858 unmodified lines
4859	4859	return -EINVAL;
4860	4860	}
4861	4861
	4862	+ if (fn->allowed && !fn->allowed(env->prog)) {
	4863	+ verbose(env, "helper call is not allowed in probe\n");
	4864	+ return -EINVAL;
	4865	+ }
	4866	+
4862	4867	/* With LD_ABS/IND some JITs save/restore skb from r1. */
4863	4868	changes_data = bpf_helper_changes_pkt_data(fn->func);
4864	4869	if (changes_data && fn->arg1_type != ARG_PTR_TO_CTX) {

tools/include/linux/btf_ids.h+50−1

@@ -3,6 +3,11 @@ · 2 unmodified lines
3	3	#ifndef _LINUX_BTF_IDS_H
4	4	#define _LINUX_BTF_IDS_H
5	5
	6	+struct btf_id_set {
	7	+ u32 cnt;
	8	+ u32 ids[];
	9	+};
	10	+
6	11	#ifdef CONFIG_DEBUG_INFO_BTF
7	12
8	13	#include <linux/compiler.h> /* for __PASTE */
@@ -62,7 +67,7 @@ asm( \ · 53 unmodified lines
62	67	".pushsection " BTF_IDS_SECTION ",\"a\"; \n" \
63	68	"." #scope " " #name "; \n" \
64	69	#name ":; \n" \
65		−".popsection; \n"); \
	70	+".popsection; \n");
66	71
67	72	#define BTF_ID_LIST(name) \
68	73	__BTF_ID_LIST(name, local) \
@@ -88,12 +93,56 @@ asm( \ · 19 unmodified lines
88	93	".zero 4 \n" \
89	94	".popsection; \n");
90	95
	96	+/*
	97	+ * The BTF_SET_START/END macros pair defines sorted list of
	98	+ * BTF IDs plus its members count, with following layout:
	99	+ *
	100	+ * BTF_SET_START(list)
	101	+ * BTF_ID(type1, name1)
	102	+ * BTF_ID(type2, name2)
	103	+ * BTF_SET_END(list)
	104	+ *
	105	+ * __BTF_ID__set__list:
	106	+ * .zero 4
	107	+ * list:
	108	+ * __BTF_ID__type1__name1__3:
	109	+ * .zero 4
	110	+ * __BTF_ID__type2__name2__4:
	111	+ * .zero 4
	112	+ *
	113	+ */
	114	+#define __BTF_SET_START(name, scope) \
	115	+asm( \
	116	+".pushsection " BTF_IDS_SECTION ",\"a\"; \n" \
	117	+"." #scope " __BTF_ID__set__" #name "; \n" \
	118	+"__BTF_ID__set__" #name ":; \n" \
	119	+".zero 4 \n" \
	120	+".popsection; \n");
	121	+
	122	+#define BTF_SET_START(name) \
	123	+__BTF_ID_LIST(name, local) \
	124	+__BTF_SET_START(name, local)
	125	+
	126	+#define BTF_SET_START_GLOBAL(name) \
	127	+__BTF_ID_LIST(name, globl) \
	128	+__BTF_SET_START(name, globl)
	129	+
	130	+#define BTF_SET_END(name) \
	131	+asm( \
	132	+".pushsection " BTF_IDS_SECTION ",\"a\"; \n" \
	133	+".size __BTF_ID__set__" #name ", .-" #name " \n" \
	134	+".popsection; \n"); \
	135	+extern struct btf_id_set name;
	136	+
91	137	#else
92	138
93	139	#define BTF_ID_LIST(name) static u32 name[5];
94	140	#define BTF_ID(prefix, name)
95	141	#define BTF_ID_UNUSED
96	142	#define BTF_ID_LIST_GLOBAL(name) u32 name[1];
	143	+#define BTF_SET_START(name) static struct btf_id_set name = { 0 };
	144	+#define BTF_SET_START_GLOBAL(name) static struct btf_id_set name = { 0 };
	145	+#define BTF_SET_END(name)
97	146
98	147	#endif /* CONFIG_DEBUG_INFO_BTF */
99	148

bpf: Add BTF_SET_START/END macros

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