[PATCH v2 bpf-next 12/14] selftests/bpf: add verifier cgroup storage tests

Roman Gushchin
2018-07-05T20:55:28Z

Add the following verifier tests to cover the cgroup storage
functionality:
1) valid access to the cgroup storage
2) invalid access: use regular hashmap instead of cgroup storage map
3) invalid access: use invalid map fd
4) invalid access: try access memory after the cgroup storage
5) invalid access: try access memory before the cgroup storage
6) invalid access: call get_local_storage() with non-zero flags

For tests 2)-6) check returned error strings.

Expected output:
$ ./test_verifier
#0/u add+sub+mul OK
#0/p add+sub+mul OK
#1/u DIV32 by 0, zero check 1 OK
...
#280/p valid cgroup storage access OK
#281/p invalid cgroup storage access 1 OK
#282/p invalid cgroup storage access 2 OK
#283/p invalid per-cgroup storage access 3 OK
#284/p invalid cgroup storage access 4 OK
#285/p invalid cgroup storage access 5 OK
...
#649/p pass modified ctx pointer to helper, 2 OK
#650/p pass modified ctx pointer to helper, 3 OK
Summary: 901 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
---
tools/testing/selftests/bpf/bpf_helpers.h | 2 +
tools/testing/selftests/bpf/test_verifier.c | 123 +++++++++++++++++++++++++++-
2 files changed, 124 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h
index f2f28b6c8915..ccd959fd940e 100644
--- a/tools/testing/selftests/bpf/bpf_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_helpers.h
@@ -133,6 +133,8 @@ static int (*bpf_rc_keydown)(void *ctx, unsigned int protocol,
(void *) BPF_FUNC_rc_keydown;
static unsigned long long (*bpf_get_current_cgroup_id)(void) =
(void *) BPF_FUNC_get_current_cgroup_id;
+static void *(*bpf_get_local_storage)(void *map, unsigned long long flags) =
+ (void *) BPF_FUNC_get_local_storage;

/* llvm builtin functions that eBPF C program may use to
* emit BPF_LD_ABS and BPF_LD_IND instructions
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 2ecd27b670d7..7016fb2964a1 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -50,7 +50,7 @@

#define MAX_INSNS BPF_MAXINSNS
#define MAX_FIXUPS 8
-#define MAX_NR_MAPS 7
+#define MAX_NR_MAPS 8
#define POINTER_VALUE 0xcafe4all
#define TEST_DATA_LEN 64

@@ -70,6 +70,7 @@ struct bpf_test {
int fixup_prog1[MAX_FIXUPS];
int fixup_prog2[MAX_FIXUPS];
int fixup_map_in_map[MAX_FIXUPS];
+ int fixup_cgroup_storage[MAX_FIXUPS];
const char *errstr;
const char *errstr_unpriv;
uint32_t retval;
@@ -4630,6 +4631,104 @@ static struct bpf_test tests[] = {
.result = REJECT,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
+ {
+ "valid cgroup storage access",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+ BPF_FUNC_get_local_storage),
+ BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, 0),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+ BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 1),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_cgroup_storage = { 1 },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_CGROUP_SKB,
+ },
+ {
+ "invalid cgroup storage access 1",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+ BPF_FUNC_get_local_storage),
+ BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, 0),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+ BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 1),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 1 },
+ .result = REJECT,
+ .errstr = "cannot pass map_type 1 into func bpf_get_local_storage",
+ .prog_type = BPF_PROG_TYPE_CGROUP_SKB,
+ },
+ {
+ "invalid cgroup storage access 2",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_LD_MAP_FD(BPF_REG_1, 1),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+ BPF_FUNC_get_local_storage),
+ BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 1),
+ BPF_EXIT_INSN(),
+ },
+ .result = REJECT,
+ .errstr = "fd 1 is not pointing to valid bpf_map",
+ .prog_type = BPF_PROG_TYPE_CGROUP_SKB,
+ },
+ {
+ "invalid per-cgroup storage access 3",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+ BPF_FUNC_get_local_storage),
+ BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, 256),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 1),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_cgroup_storage = { 1 },
+ .result = REJECT,
+ .errstr = "invalid access to map value, value_size=64 off=256 size=4",
+ .prog_type = BPF_PROG_TYPE_CGROUP_SKB,
+ },
+ {
+ "invalid cgroup storage access 4",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+ BPF_FUNC_get_local_storage),
+ BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, -2),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 1),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_cgroup_storage = { 1 },
+ .result = REJECT,
+ .errstr = "invalid access to map value, value_size=64 off=-2 size=4",
+ .prog_type = BPF_PROG_TYPE_CGROUP_SKB,
+ },
+ {
+ "invalid cgroup storage access 5",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_2, 7),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+ BPF_FUNC_get_local_storage),
+ BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, 0),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+ BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 1),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_cgroup_storage = { 1 },
+ .result = REJECT,
+ .errstr = "get_local_storage() doesn't support non-zero flags",
+ .prog_type = BPF_PROG_TYPE_CGROUP_SKB,
+ },
{
"multiple registers share map_lookup_elem result",
.insns = {
@@ -12418,6 +12517,19 @@ static int create_map_in_map(void)
return outer_map_fd;
}

+static int create_cgroup_storage(void)
+{
+ int fd;
+
+ fd = bpf_create_map(BPF_MAP_TYPE_CGROUP_STORAGE,
+ sizeof(struct bpf_cgroup_storage_key),
+ TEST_DATA_LEN, 0, 0);
+ if (fd < 0)
+ printf("Failed to create array '%s'!\n", strerror(errno));
+
+ return fd;
+}
+
static char bpf_vlog[UINT_MAX >> 8];

static void do_test_fixup(struct bpf_test *test, struct bpf_insn *prog,
@@ -12430,6 +12542,7 @@ static void do_test_fixup(struct bpf_test *test, struct bpf_insn *prog,
int *fixup_prog1 = test->fixup_prog1;
int *fixup_prog2 = test->fixup_prog2;
int *fixup_map_in_map = test->fixup_map_in_map;
+ int *fixup_cgroup_storage = test->fixup_cgroup_storage;

if (test->fill_helper)
test->fill_helper(test);
@@ -12497,6 +12610,14 @@ static void do_test_fixup(struct bpf_test *test, struct bpf_insn *prog,
fixup_map_in_map++;
} while (*fixup_map_in_map);
}
+
+ if (*fixup_cgroup_storage) {
+ map_fds[7] = create_cgroup_storage();
+ do {
+ prog[*fixup_cgroup_storage].imm = map_fds[7];
+ fixup_cgroup_storage++;
+ } while (*fixup_cgroup_storage);
+ }
}

static void do_test_single(struct bpf_test *test, bool unpriv,
--
2.14.4