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selftests/bpf: Add test cases to test narrower ctx field loads
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Add test cases in test_verifier and test_progs.
Negative tests are added in test_verifier as well.
The test in test_progs will compare the value of narrower ctx field
load result vs. the masked value of normal full-field load result,
and will fail if they are not the same.

Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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@yonghong-song @davem330
yonghong-song authored and davem330 committed Jun 14, 2017
1 parent 31fd858 commit 18f3d6b
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Showing 4 changed files with 234 additions and 1 deletion.
3 changes: 2 additions & 1 deletion tools/testing/selftests/bpf/Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,8 @@ LDLIBS += -lcap -lelf
TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \
test_align

TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o
TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o \
test_pkt_md_access.o

TEST_PROGS := test_kmod.sh

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35 changes: 35 additions & 0 deletions tools/testing/selftests/bpf/test_pkt_md_access.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,35 @@
/* Copyright (c) 2017 Facebook
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
#include <stddef.h>
#include <string.h>
#include <linux/bpf.h>
#include <linux/pkt_cls.h>
#include "bpf_helpers.h"

int _version SEC("version") = 1;

#define TEST_FIELD(TYPE, FIELD, MASK) \
{ \
TYPE tmp = *(volatile TYPE *)&skb->FIELD; \
if (tmp != ((*(volatile __u32 *)&skb->FIELD) & MASK)) \
return TC_ACT_SHOT; \
}

SEC("test1")
int process(struct __sk_buff *skb)
{
TEST_FIELD(__u8, len, 0xFF);
TEST_FIELD(__u16, len, 0xFFFF);
TEST_FIELD(__u32, len, 0xFFFFFFFF);
TEST_FIELD(__u16, protocol, 0xFFFF);
TEST_FIELD(__u32, protocol, 0xFFFFFFFF);
TEST_FIELD(__u8, hash, 0xFF);
TEST_FIELD(__u16, hash, 0xFFFF);
TEST_FIELD(__u32, hash, 0xFFFFFFFF);

return TC_ACT_OK;
}
21 changes: 21 additions & 0 deletions tools/testing/selftests/bpf/test_progs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -484,6 +484,26 @@ static void test_bpf_obj_id(void)
bpf_object__close(objs[i]);
}

static void test_pkt_md_access(void)
{
const char *file = "./test_pkt_md_access.o";
struct bpf_object *obj;
__u32 duration, retval;
int err, prog_fd;

err = bpf_prog_load(file, BPF_PROG_TYPE_SCHED_CLS, &obj, &prog_fd);
if (err)
return;

err = bpf_prog_test_run(prog_fd, 10, &pkt_v4, sizeof(pkt_v4),
NULL, NULL, &retval, &duration);
CHECK(err || retval, "",
"err %d errno %d retval %d duration %d\n",
err, errno, retval, duration);

bpf_object__close(obj);
}

int main(void)
{
struct rlimit rinf = { RLIM_INFINITY, RLIM_INFINITY };
Expand All @@ -495,6 +515,7 @@ int main(void)
test_l4lb();
test_tcp_estats();
test_bpf_obj_id();
test_pkt_md_access();

printf("Summary: %d PASSED, %d FAILED\n", pass_cnt, error_cnt);
return error_cnt ? EXIT_FAILURE : EXIT_SUCCESS;
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176 changes: 176 additions & 0 deletions tools/testing/selftests/bpf/test_verifier.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1094,6 +1094,59 @@ static struct bpf_test tests[] = {
.errstr = "invalid bpf_context access",
.result = REJECT,
},
{
"check skb->hash byte load permitted",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
#ifdef __LITTLE_ENDIAN
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, hash)),
#else
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, hash) + 3),
#endif
BPF_EXIT_INSN(),
},
.result = ACCEPT,
},
{
"check skb->hash byte load not permitted 1",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, hash) + 1),
BPF_EXIT_INSN(),
},
.errstr = "invalid bpf_context access",
.result = REJECT,
},
{
"check skb->hash byte load not permitted 2",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, hash) + 2),
BPF_EXIT_INSN(),
},
.errstr = "invalid bpf_context access",
.result = REJECT,
},
{
"check skb->hash byte load not permitted 3",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
#ifdef __LITTLE_ENDIAN
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, hash) + 3),
#else
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, hash)),
#endif
BPF_EXIT_INSN(),
},
.errstr = "invalid bpf_context access",
.result = REJECT,
},
{
"check cb access: byte, wrong type",
.insns = {
Expand Down Expand Up @@ -1187,6 +1240,37 @@ static struct bpf_test tests[] = {
.errstr = "invalid bpf_context access",
.result = REJECT,
},
{
"check skb->hash half load permitted",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
#ifdef __LITTLE_ENDIAN
BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, hash)),
#else
BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, hash) + 2),
#endif
BPF_EXIT_INSN(),
},
.result = ACCEPT,
},
{
"check skb->hash half load not permitted",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
#ifdef __LITTLE_ENDIAN
BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, hash) + 2),
#else
BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, hash)),
#endif
BPF_EXIT_INSN(),
},
.errstr = "invalid bpf_context access",
.result = REJECT,
},
{
"check cb access: half, wrong type",
.insns = {
Expand Down Expand Up @@ -5103,6 +5187,98 @@ static struct bpf_test tests[] = {
},
.result = ACCEPT,
},
{
"check bpf_perf_event_data->sample_period byte load permitted",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
#ifdef __LITTLE_ENDIAN
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
offsetof(struct bpf_perf_event_data, sample_period)),
#else
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
offsetof(struct bpf_perf_event_data, sample_period) + 7),
#endif
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_PERF_EVENT,
},
{
"check bpf_perf_event_data->sample_period half load permitted",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
#ifdef __LITTLE_ENDIAN
BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
offsetof(struct bpf_perf_event_data, sample_period)),
#else
BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
offsetof(struct bpf_perf_event_data, sample_period) + 6),
#endif
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_PERF_EVENT,
},
{
"check bpf_perf_event_data->sample_period word load permitted",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
#ifdef __LITTLE_ENDIAN
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct bpf_perf_event_data, sample_period)),
#else
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct bpf_perf_event_data, sample_period) + 4),
#endif
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_PERF_EVENT,
},
{
"check bpf_perf_event_data->sample_period dword load permitted",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1,
offsetof(struct bpf_perf_event_data, sample_period)),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_PERF_EVENT,
},
{
"check skb->data half load not permitted",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
#ifdef __LITTLE_ENDIAN
BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, data)),
#else
BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, data) + 2),
#endif
BPF_EXIT_INSN(),
},
.result = REJECT,
.errstr = "invalid bpf_context access",
},
{
"check skb->tc_classid half load not permitted for lwt prog",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
#ifdef __LITTLE_ENDIAN
BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, tc_classid)),
#else
BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, tc_classid) + 2),
#endif
BPF_EXIT_INSN(),
},
.result = REJECT,
.errstr = "invalid bpf_context access",
.prog_type = BPF_PROG_TYPE_LWT_IN,
},
};

static int probe_filter_length(const struct bpf_insn *fp)
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