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bpf: increase bpf test coverage

PATCH New Alexei Starovoitov 1 participant 3 messages Jan 18, 2018

Subsystems (7)
Networking Network drivers Kselftest BPF +3 more subsystems
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Alexei Starovoitov

author maintainer
#0 lore raw

cover bpf: increase bpf test coverage

BPF verifier has 700+ tests used to check correctness of the verifier. Beyond checking the verifier log tell kernel to run accepted programs as well via bpf_prog_test_run() command. That improves quality of the tests and increases bpf test coverage.

Alexei Starovoitov (2):
bpf: allow socket_filter programs to use bpf_prog_test_run selftests/bpf: make test_verifier run most programs

 kernel/bpf/syscall.c                        |  2 ++
 net/core/filter.c                           |  1 +
 tools/testing/selftests/bpf/test_verifier.c | 50 ++++++++++++++++++++++++++++-
 3 files changed, 52 insertions(+), 1 deletion(-)
Signature · 1 line
2.9.5
author maintainer
#1 lore raw

PATCH 1/2 bpf: allow socket_filter programs to use bpf_prog_test_run

in order to improve test coverage allow socket_filter program type to be run via bpf_prog_test_run command.
Since such programs can be loaded by non-root tighten permissions for bpf_prog_test_run to be root only
to avoid surprises.

Signed-off-by Alexei Starovoitov <[email protected]>
---
 kernel/bpf/syscall.c | 2 ++
 net/core/filter.c    | 1 +
 2 files changed, 3 insertions(+)
kernel/bpf/syscall.c +2 -0
index c691b9e972e3..08ca42b1b916 100644
@@ -1504,6 +1504,8 @@ static int bpf_prog_test_run(const union bpf_attr *attr,
 	struct bpf_prog *prog;
 	int ret = -ENOTSUPP;
 
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
 	if (CHECK_ATTR(BPF_PROG_TEST_RUN))
 		return -EINVAL;
net/core/filter.c +1 -0
index db2ee8c7e1bd..30fafaaa90fa 100644
@@ -4526,6 +4526,7 @@ const struct bpf_verifier_ops sk_filter_verifier_ops = {
 };
 
 const struct bpf_prog_ops sk_filter_prog_ops = {
+	.test_run		= bpf_prog_test_run_skb,
 };
 
 const struct bpf_verifier_ops tc_cls_act_verifier_ops = {
Signature · 1 line
2.9.5
author maintainer
#2 lore raw

PATCH 2/2 selftests/bpf: make test_verifier run most programs

In reply to Alexei Starovoitov

to improve test coverage make test_verifier run all successfully loaded programs on 64-byte zero initialized data.
For clsbpf and xdp it means empty 64-byte packet.
For lwt and socket_filters it's 64-byte packet where skb->data points after L2.

Signed-off-by Alexei Starovoitov <[email protected]>
---
 tools/testing/selftests/bpf/test_verifier.c | 50 ++++++++++++++++++++++++++++-
 1 file changed, 49 insertions(+), 1 deletion(-)
tools/testing/selftests/bpf/test_verifier.c +49 -1
index 543847957fdd..87da8d1bf2dd 100644
@@ -29,6 +29,7 @@
 #include <linux/filter.h>
 #include <linux/bpf_perf_event.h>
 #include <linux/bpf.h>
+#include <linux/if_ether.h>
 
 #include <bpf/bpf.h>
 

@@ -49,6 +50,8 @@
 #define MAX_INSNS	512
 #define MAX_FIXUPS	8
 #define MAX_NR_MAPS	4
+#define POINTER_VALUE	0xcafe4all
+#define TEST_DATA_LEN	64
 
 #define F_NEEDS_EFFICIENT_UNALIGNED_ACCESS	(1 << 0)
 #define F_LOAD_WITH_STRICT_ALIGNMENT		(1 << 1)

@@ -62,6 +65,7 @@ struct bpf_test {
 	int fixup_map_in_map[MAX_FIXUPS];
 	const char *errstr;
 	const char *errstr_unpriv;
+	uint32_t retval;
 	enum {
 		UNDEF,
 		ACCEPT,

@@ -95,6 +99,7 @@ static struct bpf_test tests[] = {
 			BPF_EXIT_INSN(),
 		},
 		.result = ACCEPT,
+		.retval = -3,
 	},
 	{
 		"unreachable",

@@ -210,6 +215,7 @@ static struct bpf_test tests[] = {
 			BPF_EXIT_INSN(),
 		},
 		.result = ACCEPT,
+		.retval = 1,
 	},
 	{
 		"test8 ld_imm64",

@@ -477,6 +483,7 @@ static struct bpf_test tests[] = {
 		.errstr_unpriv = "R0 leaks addr",
 		.result = ACCEPT,
 		.result_unpriv = REJECT,
+		.retval = POINTER_VALUE,
 	},
 	{
 		"check valid spill/fill, skb mark",

@@ -763,6 +770,7 @@ static struct bpf_test tests[] = {
 		.errstr_unpriv = "R1 pointer comparison",
 		.result_unpriv = REJECT,
 		.result = ACCEPT,
+		.retval = -ENOENT,
 	},
 	{
 		"jump test 4",

@@ -1783,6 +1791,7 @@ static struct bpf_test tests[] = {
 			BPF_EXIT_INSN(),
 		},
 		.result = ACCEPT,
+		.retval = 0xfaceb00c,
 	},
 	{
 		"PTR_TO_STACK store/load - bad alignment on off",

@@ -1841,6 +1850,7 @@ static struct bpf_test tests[] = {
 		.result = ACCEPT,
 		.result_unpriv = REJECT,
 		.errstr_unpriv = "R0 leaks addr",
+		.retval = POINTER_VALUE,
 	},
 	{
 		"unpriv: add const to pointer",

@@ -2014,6 +2024,7 @@ static struct bpf_test tests[] = {
 			BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, 0),
 			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
 				     BPF_FUNC_get_hash_recalc),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
 			BPF_EXIT_INSN(),
 		},
 		.result = ACCEPT,

@@ -2778,6 +2789,7 @@ static struct bpf_test tests[] = {
 		},
 		.result = ACCEPT,
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+		.retval = 1,
 	},
 	{
 		"direct packet access: test12 (and, good access)",

@@ -2802,6 +2814,7 @@ static struct bpf_test tests[] = {
 		},
 		.result = ACCEPT,
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+		.retval = 1,
 	},
 	{
 		"direct packet access: test13 (branches, good access)",

@@ -2832,6 +2845,7 @@ static struct bpf_test tests[] = {
 		},
 		.result = ACCEPT,
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+		.retval = 1,
 	},
 	{
 		"direct packet access: test14 (pkt_ptr += 0, CONST_IMM, good access)",

@@ -2855,6 +2869,7 @@ static struct bpf_test tests[] = {
 		},
 		.result = ACCEPT,
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+		.retval = 1,
 	},
 	{
 		"direct packet access: test15 (spill with xadd)",

@@ -3141,6 +3156,7 @@ static struct bpf_test tests[] = {
 		},
 		.result = ACCEPT,
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+		.retval = 1,
 	},
 	{
 		"direct packet access: test28 (marking on <=, bad access)",

@@ -5758,6 +5774,7 @@ static struct bpf_test tests[] = {
 		},
 		.result = ACCEPT,
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+		.retval = 0 /* csum_diff of 64-byte packet */,
 	},
 	{
 		"helper access to variable memory: size = 0 not allowed on NULL (!ARG_PTR_TO_MEM_OR_NULL)",

@@ -6126,6 +6143,7 @@ static struct bpf_test tests[] = {
 		},
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
 		.result = ACCEPT,
+		.retval = 42 /* ultimate return value */,
 	},
 	{
 		"ld_ind: check calling conv, r1",

@@ -6197,6 +6215,7 @@ static struct bpf_test tests[] = {
 			BPF_EXIT_INSN(),
 		},
 		.result = ACCEPT,
+		.retval = 1,
 	},
 	{
 		"check bpf_perf_event_data->sample_period byte load permitted",

@@ -7184,6 +7203,7 @@ static struct bpf_test tests[] = {
 		},
 		.fixup_map1 = { 3 },
 		.result = ACCEPT,
+		.retval = POINTER_VALUE,
 		.result_unpriv = REJECT,
 		.errstr_unpriv = "R0 leaks addr as return value"
 	},

@@ -7204,6 +7224,7 @@ static struct bpf_test tests[] = {
 		},
 		.fixup_map1 = { 3 },
 		.result = ACCEPT,
+		.retval = POINTER_VALUE,
 		.result_unpriv = REJECT,
 		.errstr_unpriv = "R0 leaks addr as return value"
 	},

@@ -7645,6 +7666,7 @@ static struct bpf_test tests[] = {
 			BPF_EXIT_INSN(),
 		},
 		.result = ACCEPT,
+		.retval = TEST_DATA_LEN,
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
 	},
 	{

@@ -8665,6 +8687,7 @@ static struct bpf_test tests[] = {
 		.errstr_unpriv = "function calls to other bpf functions are allowed for root only",
 		.result_unpriv = REJECT,
 		.result = ACCEPT,
+		.retval = 1,
 	},
 	{
 		"calls: overlapping caller/callee",

@@ -8860,6 +8883,7 @@ static struct bpf_test tests[] = {
 		},
 		.prog_type = BPF_PROG_TYPE_SCHED_ACT,
 		.result = ACCEPT,
+		.retval = TEST_DATA_LEN,
 	},
 	{
 		"calls: callee using args1",

@@ -8872,6 +8896,7 @@ static struct bpf_test tests[] = {
 		.errstr_unpriv = "allowed for root only",
 		.result_unpriv = REJECT,
 		.result = ACCEPT,
+		.retval = POINTER_VALUE,
 	},
 	{
 		"calls: callee using wrong args2",

@@ -8902,6 +8927,7 @@ static struct bpf_test tests[] = {
 		.errstr_unpriv = "allowed for root only",
 		.result_unpriv = REJECT,
 		.result = ACCEPT,
+		.retval = TEST_DATA_LEN + TEST_DATA_LEN - ETH_HLEN - ETH_HLEN,
 	},
 	{
 		"calls: callee changing pkt pointers",

@@ -8950,6 +8976,7 @@ static struct bpf_test tests[] = {
 		},
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
 		.result = ACCEPT,
+		.retval = TEST_DATA_LEN + TEST_DATA_LEN,
 	},
 	{
 		"calls: calls with stack arith",

@@ -8968,6 +8995,7 @@ static struct bpf_test tests[] = {
 		},
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
 		.result = ACCEPT,
+		.retval = 42,
 	},
 	{
 		"calls: calls with misaligned stack access",

@@ -9001,6 +9029,7 @@ static struct bpf_test tests[] = {
 		},
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
 		.result = ACCEPT,
+		.retval = 43,
 	},
 	{
 		"calls: calls control flow, jump test 2",

@@ -9493,6 +9522,7 @@ static struct bpf_test tests[] = {
 		},
 		.prog_type = BPF_PROG_TYPE_XDP,
 		.result = ACCEPT,
+		.retval = 42,
 	},
 	{
 		"calls: write into callee stack frame",

@@ -10104,6 +10134,7 @@ static struct bpf_test tests[] = {
 		},
 		.result = ACCEPT,
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+		.retval = POINTER_VALUE,
 	},
 	{
 		"calls: pkt_ptr spill into caller stack 2",

@@ -10169,6 +10200,7 @@ static struct bpf_test tests[] = {
 		},
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
 		.result = ACCEPT,
+		.retval = 1,
 	},
 	{
 		"calls: pkt_ptr spill into caller stack 4",

@@ -10202,6 +10234,7 @@ static struct bpf_test tests[] = {
 		},
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
 		.result = ACCEPT,
+		.retval = 1,
 	},
 	{
 		"calls: pkt_ptr spill into caller stack 5",

@@ -10610,10 +10643,12 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 	int fd_prog, expected_ret, reject_from_alignment;
 	struct bpf_insn *prog = test->insns;
 	int prog_len = probe_filter_length(prog);
+	char data_in[TEST_DATA_LEN] = {};
 	int prog_type = test->prog_type;
 	int map_fds[MAX_NR_MAPS];
 	const char *expected_err;
-	int i;
+	uint32_t retval;
+	int i, err;
 
 	for (i = 0; i < MAX_NR_MAPS; i++)
 		map_fds[i] = -1;

@@ -10656,6 +10691,19 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 		}
 	}
 
+	if (fd_prog >= 0) {
+		err = bpf_prog_test_run(fd_prog, 1, data_in, sizeof(data_in),
+					NULL, NULL, &retval, NULL);
+		if (err && errno != 524/*ENOTSUPP*/ && errno != EPERM) {
+			printf("Unexpected bpf_prog_test_run error\n");
+			goto fail_log;
+		}
+		if (!err && retval != test->retval &&
+		    test->retval != POINTER_VALUE) {
+			printf("FAIL retval %d != %d\n", retval, test->retval);
+			goto fail_log;
+		}
+	}
 	(*passes)++;
 	printf("OK%s\n", reject_from_alignment ?
 	       " (NOTE: reject due to unknown alignment)" : "");
Signature · 1 line
2.9.5