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selftests/bpf: Add tests to validate log_true_size feature

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Add additional test cases validating that log_true_size is consistent
between fixed and rotating log modes, and that log_true_size can be
used *exactly* without causing -ENOSPC, while using just 1 byte shorter
log buffer would cause -ENOSPC.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-18-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko 2023-04-06 16:42:03 -07:00 committed by Daniel Borkmann
parent 097d8002b7
commit 5787540827
1 changed files with 76 additions and 16 deletions
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92
tools/testing/selftests/bpf/prog_tests/verifier_log.c
View File

@ -18,25 +18,41 @@ static bool check_prog_load(int prog_fd, bool expect_err, const char *tag)
if (!ASSERT_GT(prog_fd, 0, tag))
return false;
}
if (prog_fd >= 0)
close(prog_fd);
return true;
}
static struct {
/* strategically placed before others to avoid accidental modification by kernel */
char filler[1024];
char buf[1024];
/* strategically placed after buf[] to catch more accidental corruptions */
char reference[1024];
} logs;
static const struct bpf_insn *insns;
static size_t insn_cnt;
static int load_prog(struct bpf_prog_load_opts *opts, bool expect_load_error)
{
int prog_fd;
prog_fd = bpf_prog_load(BPF_PROG_TYPE_RAW_TRACEPOINT, "log_prog",
"GPL", insns, insn_cnt, opts);
check_prog_load(prog_fd, expect_load_error, "prog_load");
return prog_fd;
}
static void verif_log_subtest(const char *name, bool expect_load_error, int log_level)
{
LIBBPF_OPTS(bpf_prog_load_opts, opts);
struct {
/* strategically placed before others to avoid accidental modification by kernel */
char filler[1024];
char buf[1024];
/* strategically placed after buf[] to catch more accidental corruptions */
char reference[1024];
} logs;
char *exp_log, prog_name[16], op_name[32];
struct test_log_buf *skel;
struct bpf_program *prog;
const struct bpf_insn *insns;
size_t insn_cnt, fixed_log_sz;
int i, mode, err, prog_fd;
size_t fixed_log_sz;
__u32 log_true_sz_fixed, log_true_sz_rolling;
int i, mode, err, prog_fd, res;
skel = test_log_buf__open();
if (!ASSERT_OK_PTR(skel, "skel_open"))
@ -61,11 +77,7 @@ static void verif_log_subtest(const char *name, bool expect_load_error, int log_
opts.log_buf = logs.reference;
opts.log_size = sizeof(logs.reference);
opts.log_level = log_level | 8 /* BPF_LOG_FIXED */;
prog_fd = bpf_prog_load(BPF_PROG_TYPE_RAW_TRACEPOINT, "log_fixed",
"GPL", insns, insn_cnt, &opts);
if (!check_prog_load(prog_fd, expect_load_error, "fixed_buf_prog_load"))
goto cleanup;
close(prog_fd);
load_prog(&opts, expect_load_error);
fixed_log_sz = strlen(logs.reference) + 1;
if (!ASSERT_GT(fixed_log_sz, 50, "fixed_log_sz"))
@ -89,7 +101,7 @@ static void verif_log_subtest(const char *name, bool expect_load_error, int log_
opts.log_level = log_level | 8; /* fixed-length log */
opts.log_size = 25;
prog_fd = bpf_prog_load(BPF_PROG_TYPE_RAW_TRACEPOINT, "log_fixed50",
prog_fd = bpf_prog_load(BPF_PROG_TYPE_RAW_TRACEPOINT, "log_fixed25",
"GPL", insns, insn_cnt, &opts);
if (!ASSERT_EQ(prog_fd, -ENOSPC, "unexpected_log_fixed_prog_load_result")) {
if (prog_fd >= 0)
@ -162,6 +174,54 @@ static void verif_log_subtest(const char *name, bool expect_load_error, int log_
}
}
/* (FIXED) get actual log size */
opts.log_buf = logs.buf;
opts.log_level = log_level | 8; /* BPF_LOG_FIXED */
opts.log_size = sizeof(logs.buf);
res = load_prog(&opts, expect_load_error);
ASSERT_NEQ(res, -ENOSPC, "prog_load_res_fixed");
log_true_sz_fixed = opts.log_true_size;
ASSERT_GT(log_true_sz_fixed, 0, "log_true_sz_fixed");
/* (ROLLING) get actual log size */
opts.log_buf = logs.buf;
opts.log_level = log_level;
opts.log_size = sizeof(logs.buf);
res = load_prog(&opts, expect_load_error);
ASSERT_NEQ(res, -ENOSPC, "prog_load_res_rolling");
log_true_sz_rolling = opts.log_true_size;
ASSERT_EQ(log_true_sz_rolling, log_true_sz_fixed, "log_true_sz_eq");
/* (FIXED) expect -ENOSPC for one byte short log */
opts.log_buf = logs.buf;
opts.log_level = log_level | 8; /* BPF_LOG_FIXED */
opts.log_size = log_true_sz_fixed - 1;
res = load_prog(&opts, true /* should fail */);
ASSERT_EQ(res, -ENOSPC, "prog_load_res_too_short_fixed");
/* (FIXED) expect *not* -ENOSPC with exact log_true_size buffer */
opts.log_buf = logs.buf;
opts.log_level = log_level | 8; /* BPF_LOG_FIXED */
opts.log_size = log_true_sz_fixed;
res = load_prog(&opts, expect_load_error);
ASSERT_NEQ(res, -ENOSPC, "prog_load_res_just_right_fixed");
/* (ROLLING) expect -ENOSPC for one byte short log */
opts.log_buf = logs.buf;
opts.log_level = log_level;
opts.log_size = log_true_sz_rolling - 1;
res = load_prog(&opts, true /* should fail */);
ASSERT_EQ(res, -ENOSPC, "prog_load_res_too_short_rolling");
/* (ROLLING) expect *not* -ENOSPC with exact log_true_size buffer */
opts.log_buf = logs.buf;
opts.log_level = log_level;
opts.log_size = log_true_sz_rolling;
res = load_prog(&opts, expect_load_error);
ASSERT_NEQ(res, -ENOSPC, "prog_load_res_just_right_rolling");
cleanup:
test_log_buf__destroy(skel);
}