[PATCH bpf-next v4 0/6] Fix bugs found by ASAN when running selftests

[PATCH bpf-next v4 0/6] Fix bugs found by ASAN when running selftests

[Xu Kuohai]

From: Xu Kuohai <xukuohai@huawei.com>

This series fixes bugs found by ASAN when running bpf selftests on arm64.

v4:
- Address Andrii's suggestions

v3: https://lore.kernel.org/bpf/5311e154-c2d4-91a5-ccb8-f5adede579ed@huawei.com
- Fix error failure of case test_xdp_adjust_tail_grow exposed by this series

v2: https://lore.kernel.org/bpf/20221010070454.577433-1-xukuohai@huaweicloud.com
- Rebase and fix conflict

v1: https://lore.kernel.org/bpf/20221009131830.395569-1-xukuohai@huaweicloud.com

Xu Kuohai (6):
  libbpf: Fix use-after-free in btf_dump_name_dups
  libbpf: Fix memory leak in parse_usdt_arg()
  selftests/bpf: Fix memory leak caused by not destroying skeleton
  selftest/bpf: Fix memory leak in kprobe_multi_test
  selftests/bpf: Fix error failure of case test_xdp_adjust_tail_grow
  selftest/bpf: Fix error usage of ASSERT_OK in xdp_adjust_tail.c

 tools/lib/bpf/btf_dump.c                      | 30 +++++++++++++++++--
 tools/lib/bpf/usdt.c                          | 11 +++----
 .../bpf/prog_tests/kprobe_multi_test.c        | 26 ++++++++--------
 .../selftests/bpf/prog_tests/map_kptr.c       |  3 +-
 .../selftests/bpf/prog_tests/tracing_struct.c |  3 +-
 .../bpf/prog_tests/xdp_adjust_tail.c          |  7 +++--
 6 files changed, 53 insertions(+), 27 deletions(-)

-- 
2.30.2

[PATCH bpf-next v4 1/6] libbpf: Fix use-after-free in btf_dump_name_dups

[Xu Kuohai]

From: Xu Kuohai <xukuohai@huawei.com>

ASAN reports an use-after-free in btf_dump_name_dups:

ERROR: AddressSanitizer: heap-use-after-free on address 0xffff927006db at pc 0xaaaab5dfb618 bp 0xffffdd89b890 sp 0xffffdd89b928
READ of size 2 at 0xffff927006db thread T0
    #0 0xaaaab5dfb614 in __interceptor_strcmp.part.0 (test_progs+0x21b614)
    #1 0xaaaab635f144 in str_equal_fn tools/lib/bpf/btf_dump.c:127
    #2 0xaaaab635e3e0 in hashmap_find_entry tools/lib/bpf/hashmap.c:143
    #3 0xaaaab635e72c in hashmap__find tools/lib/bpf/hashmap.c:212
    #4 0xaaaab6362258 in btf_dump_name_dups tools/lib/bpf/btf_dump.c:1525
    #5 0xaaaab636240c in btf_dump_resolve_name tools/lib/bpf/btf_dump.c:1552
    #6 0xaaaab6362598 in btf_dump_type_name tools/lib/bpf/btf_dump.c:1567
    #7 0xaaaab6360b48 in btf_dump_emit_struct_def tools/lib/bpf/btf_dump.c:912
    #8 0xaaaab6360630 in btf_dump_emit_type tools/lib/bpf/btf_dump.c:798
    #9 0xaaaab635f720 in btf_dump__dump_type tools/lib/bpf/btf_dump.c:282
    #10 0xaaaab608523c in test_btf_dump_incremental tools/testing/selftests/bpf/prog_tests/btf_dump.c:236
    #11 0xaaaab6097530 in test_btf_dump tools/testing/selftests/bpf/prog_tests/btf_dump.c:875
    #12 0xaaaab6314ed0 in run_one_test tools/testing/selftests/bpf/test_progs.c:1062
    #13 0xaaaab631a0a8 in main tools/testing/selftests/bpf/test_progs.c:1697
    #14 0xffff9676d214 in __libc_start_main ../csu/libc-start.c:308
    #15 0xaaaab5d65990  (test_progs+0x185990)

0xffff927006db is located 11 bytes inside of 16-byte region [0xffff927006d0,0xffff927006e0)
freed by thread T0 here:
    #0 0xaaaab5e2c7c4 in realloc (test_progs+0x24c7c4)
    #1 0xaaaab634f4a0 in libbpf_reallocarray tools/lib/bpf/libbpf_internal.h:191
    #2 0xaaaab634f840 in libbpf_add_mem tools/lib/bpf/btf.c:163
    #3 0xaaaab636643c in strset_add_str_mem tools/lib/bpf/strset.c:106
    #4 0xaaaab6366560 in strset__add_str tools/lib/bpf/strset.c:157
    #5 0xaaaab6352d70 in btf__add_str tools/lib/bpf/btf.c:1519
    #6 0xaaaab6353e10 in btf__add_field tools/lib/bpf/btf.c:2032
    #7 0xaaaab6084fcc in test_btf_dump_incremental tools/testing/selftests/bpf/prog_tests/btf_dump.c:232
    #8 0xaaaab6097530 in test_btf_dump tools/testing/selftests/bpf/prog_tests/btf_dump.c:875
    #9 0xaaaab6314ed0 in run_one_test tools/testing/selftests/bpf/test_progs.c:1062
    #10 0xaaaab631a0a8 in main tools/testing/selftests/bpf/test_progs.c:1697
    #11 0xffff9676d214 in __libc_start_main ../csu/libc-start.c:308
    #12 0xaaaab5d65990  (test_progs+0x185990)

previously allocated by thread T0 here:
    #0 0xaaaab5e2c7c4 in realloc (test_progs+0x24c7c4)
    #1 0xaaaab634f4a0 in libbpf_reallocarray tools/lib/bpf/libbpf_internal.h:191
    #2 0xaaaab634f840 in libbpf_add_mem tools/lib/bpf/btf.c:163
    #3 0xaaaab636643c in strset_add_str_mem tools/lib/bpf/strset.c:106
    #4 0xaaaab6366560 in strset__add_str tools/lib/bpf/strset.c:157
    #5 0xaaaab6352d70 in btf__add_str tools/lib/bpf/btf.c:1519
    #6 0xaaaab6353ff0 in btf_add_enum_common tools/lib/bpf/btf.c:2070
    #7 0xaaaab6354080 in btf__add_enum tools/lib/bpf/btf.c:2102
    #8 0xaaaab6082f50 in test_btf_dump_incremental tools/testing/selftests/bpf/prog_tests/btf_dump.c:162
    #9 0xaaaab6097530 in test_btf_dump tools/testing/selftests/bpf/prog_tests/btf_dump.c:875
    #10 0xaaaab6314ed0 in run_one_test tools/testing/selftests/bpf/test_progs.c:1062
    #11 0xaaaab631a0a8 in main tools/testing/selftests/bpf/test_progs.c:1697
    #12 0xffff9676d214 in __libc_start_main ../csu/libc-start.c:308
    #13 0xaaaab5d65990  (test_progs+0x185990)

The reason is that the key stored in hash table name_map is a string
address, and the string memory is allocated by realloc() function, when
the memory is resized by realloc() later, the old memory may be freed,
so the address stored in name_map references to a freed memory, causing
use-after-free.

Fix it by storing duplicated string address in name_map.

Fixes: 919d2b1dbb07 ("libbpf: Allow modification of BTF and add btf__add_str API")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
---
 tools/lib/bpf/btf_dump.c | 30 +++++++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index 4221f73a74d0..370becb82c11 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -219,6 +219,17 @@ static int btf_dump_resize(struct btf_dump *d)
 	return 0;
 }
 
+static void btf_dump_free_names(struct hashmap *map)
+{
+	size_t bkt;
+	struct hashmap_entry *cur;
+
+	hashmap__for_each_entry(map, cur, bkt)
+		free((void *)cur->key);
+
+	hashmap__free(map);
+}
+
 void btf_dump__free(struct btf_dump *d)
 {
 	int i;
@@ -237,8 +248,8 @@ void btf_dump__free(struct btf_dump *d)
 	free(d->cached_names);
 	free(d->emit_queue);
 	free(d->decl_stack);
-	hashmap__free(d->type_names);
-	hashmap__free(d->ident_names);
+	btf_dump_free_names(d->type_names);
+	btf_dump_free_names(d->ident_names);
 
 	free(d);
 }
@@ -1520,11 +1531,24 @@ static void btf_dump_emit_type_cast(struct btf_dump *d, __u32 id,
 static size_t btf_dump_name_dups(struct btf_dump *d, struct hashmap *name_map,
 				 const char *orig_name)
 {
+	int err;
+	char *old_name;
+	char *new_name;
 	size_t dup_cnt = 0;
 
+	new_name = strdup(orig_name);
+	if (!new_name)
+		return 1;
+
 	hashmap__find(name_map, orig_name, (void **)&dup_cnt);
 	dup_cnt++;
-	hashmap__set(name_map, orig_name, (void *)dup_cnt, NULL, NULL);
+
+	err = hashmap__set(name_map, new_name, (void *)dup_cnt,
+			   (const void **)&old_name, NULL);
+	if (err)
+		free(new_name);
+
+	free(old_name);
 
 	return dup_cnt;
 }
-- 
2.30.2

[PATCH bpf-next v4 2/6] libbpf: Fix memory leak in parse_usdt_arg()

[Xu Kuohai]

From: Xu Kuohai <xukuohai@huawei.com>

In the arm64 version of parse_usdt_arg(), when sscanf returns 2, reg_name
is allocated but not freed. Fix it.

Fixes: 0f8619929c57 ("libbpf: Usdt aarch64 arg parsing support")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
---
 tools/lib/bpf/usdt.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c
index e83b497c2245..49f3c3b7f609 100644
--- a/tools/lib/bpf/usdt.c
+++ b/tools/lib/bpf/usdt.c
@@ -1348,25 +1348,23 @@ static int calc_pt_regs_off(const char *reg_name)
 
 static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)
 {
-	char *reg_name = NULL;
+	char reg_name[16];
 	int arg_sz, len, reg_off;
 	long off;
 
-	if (sscanf(arg_str, " %d @ \[ %m[a-z0-9], %ld ] %n", &arg_sz, &reg_name, &off, &len) == 3) {
+	if (sscanf(arg_str, " %d @ \[ %15[a-z0-9], %ld ] %n", &arg_sz, reg_name, &off, &len) == 3) {
 		/* Memory dereference case, e.g., -4@[sp, 96] */
 		arg->arg_type = USDT_ARG_REG_DEREF;
 		arg->val_off = off;
 		reg_off = calc_pt_regs_off(reg_name);
-		free(reg_name);
 		if (reg_off < 0)
 			return reg_off;
 		arg->reg_off = reg_off;
-	} else if (sscanf(arg_str, " %d @ \[ %m[a-z0-9] ] %n", &arg_sz, &reg_name, &len) == 2) {
+	} else if (sscanf(arg_str, " %d @ \[ %15[a-z0-9] ] %n", &arg_sz, reg_name, &len) == 2) {
 		/* Memory dereference case, e.g., -4@[sp] */
 		arg->arg_type = USDT_ARG_REG_DEREF;
 		arg->val_off = 0;
 		reg_off = calc_pt_regs_off(reg_name);
-		free(reg_name);
 		if (reg_off < 0)
 			return reg_off;
 		arg->reg_off = reg_off;
@@ -1375,12 +1373,11 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
 		arg->arg_type = USDT_ARG_CONST;
 		arg->val_off = off;
 		arg->reg_off = 0;
-	} else if (sscanf(arg_str, " %d @ %m[a-z0-9] %n", &arg_sz, &reg_name, &len) == 2) {
+	} else if (sscanf(arg_str, " %d @ %15[a-z0-9] %n", &arg_sz, reg_name, &len) == 2) {
 		/* Register read case, e.g., -8@x4 */
 		arg->arg_type = USDT_ARG_REG;
 		arg->val_off = 0;
 		reg_off = calc_pt_regs_off(reg_name);
-		free(reg_name);
 		if (reg_off < 0)
 			return reg_off;
 		arg->reg_off = reg_off;
-- 
2.30.2

[PATCH bpf-next v4 3/6] selftests/bpf: Fix memory leak caused by not destroying skeleton

[Xu Kuohai]

From: Xu Kuohai <xukuohai@huawei.com>

Some test cases does not destroy skeleton object correctly, causing ASAN
to report memory leak warning. Fix it.

Fixes: 0ef6740e9777 ("selftests/bpf: Add tests for kptr_ref refcounting")
Fixes: 1642a3945e22 ("selftests/bpf: Add struct argument tests with fentry/fexit programs.")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
---
 tools/testing/selftests/bpf/prog_tests/map_kptr.c       | 3 ++-
 tools/testing/selftests/bpf/prog_tests/tracing_struct.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/map_kptr.c b/tools/testing/selftests/bpf/prog_tests/map_kptr.c
index fdcea7a61491..0d66b1524208 100644
--- a/tools/testing/selftests/bpf/prog_tests/map_kptr.c
+++ b/tools/testing/selftests/bpf/prog_tests/map_kptr.c
@@ -105,7 +105,7 @@ static void test_map_kptr_success(bool test_run)
 	ASSERT_OK(opts.retval, "test_map_kptr_ref2 retval");
 
 	if (test_run)
-		return;
+		goto exit;
 
 	ret = bpf_map__update_elem(skel->maps.array_map,
 				   &key, sizeof(key), buf, sizeof(buf), 0);
@@ -132,6 +132,7 @@ static void test_map_kptr_success(bool test_run)
 	ret = bpf_map__delete_elem(skel->maps.lru_hash_map, &key, sizeof(key), 0);
 	ASSERT_OK(ret, "lru_hash_map delete");
 
+exit:
 	map_kptr__destroy(skel);
 }
 
diff --git a/tools/testing/selftests/bpf/prog_tests/tracing_struct.c b/tools/testing/selftests/bpf/prog_tests/tracing_struct.c
index d5022b91d1e4..48dc9472e160 100644
--- a/tools/testing/selftests/bpf/prog_tests/tracing_struct.c
+++ b/tools/testing/selftests/bpf/prog_tests/tracing_struct.c
@@ -15,7 +15,7 @@ static void test_fentry(void)
 
 	err = tracing_struct__attach(skel);
 	if (!ASSERT_OK(err, "tracing_struct__attach"))
-		return;
+		goto destroy_skel;
 
 	ASSERT_OK(trigger_module_test_read(256), "trigger_read");
 
@@ -54,6 +54,7 @@ static void test_fentry(void)
 	ASSERT_EQ(skel->bss->t5_ret, 1, "t5 ret");
 
 	tracing_struct__detach(skel);
+destroy_skel:
 	tracing_struct__destroy(skel);
 }
 
-- 
2.30.2

[PATCH bpf-next v4 4/6] selftest/bpf: Fix memory leak in kprobe_multi_test

[Xu Kuohai]

From: Xu Kuohai <xukuohai@huawei.com>

The get_syms() function in kprobe_multi_test.c does not free the string
memory allocated by sscanf correctly. Fix it.

Fixes: 5b6c7e5c4434 ("selftests/bpf: Add attach bench test")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
---
 .../bpf/prog_tests/kprobe_multi_test.c        | 26 ++++++++++---------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
index d457a55ff408..287b3ac40227 100644
--- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
+++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
@@ -325,7 +325,7 @@ static bool symbol_equal(const void *key1, const void *key2, void *ctx __maybe_u
 static int get_syms(char ***symsp, size_t *cntp)
 {
 	size_t cap = 0, cnt = 0, i;
-	char *name, **syms = NULL;
+	char *name = NULL, **syms = NULL;
 	struct hashmap *map;
 	char buf[256];
 	FILE *f;
@@ -352,6 +352,8 @@ static int get_syms(char ***symsp, size_t *cntp)
 		/* skip modules */
 		if (strchr(buf, '['))
 			continue;
+
+		free(name);
 		if (sscanf(buf, "%ms$*[^\n]\n", &name) != 1)
 			continue;
 		/*
@@ -369,32 +371,32 @@ static int get_syms(char ***symsp, size_t *cntp)
 		if (!strncmp(name, "__ftrace_invalid_address__",
 			     sizeof("__ftrace_invalid_address__") - 1))
 			continue;
+
 		err = hashmap__add(map, name, NULL);
-		if (err) {
-			free(name);
-			if (err == -EEXIST)
-				continue;
+		if (err == -EEXIST)
+			continue;
+		if (err)
 			goto error;
-		}
+
 		err = libbpf_ensure_mem((void **) &syms, &cap,
 					sizeof(*syms), cnt + 1);
-		if (err) {
-			free(name);
+		if (err)
 			goto error;
-		}
-		syms[cnt] = name;
-		cnt++;
+
+		syms[cnt++] = name;
+		name = NULL;
 	}
 
 	*symsp = syms;
 	*cntp = cnt;
 
 error:
+	free(name);
 	fclose(f);
 	hashmap__free(map);
 	if (err) {
 		for (i = 0; i < cnt; i++)
-			free(syms[cnt]);
+			free(syms[i]);
 		free(syms);
 	}
 	return err;
-- 
2.30.2

[PATCH bpf-next v4 5/6] selftests/bpf: Fix error failure of case test_xdp_adjust_tail_grow

[Xu Kuohai]

From: Xu Kuohai <xukuohai@huawei.com>

test_xdp_adjust_tail_grow failed with ipv6:
  test_xdp_adjust_tail_grow:FAIL:ipv6 unexpected error: -28 (errno 28)

The reason is that this test case tests ipv4 before ipv6, and when ipv4
test finished, topts.data_size_out was set to 54, which is smaller than the
ipv6 output data size 114, so ipv6 test fails with NOSPC error.

Fix it by reset topts.data_size_out to sizeof(buf) before testing ipv6.

Fixes: 04fcb5f9a104 ("selftests/bpf: Migrate from bpf_prog_test_run")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
---
 tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
index 9b9cf8458adf..009ee37607df 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
@@ -63,6 +63,7 @@ static void test_xdp_adjust_tail_grow(void)
 	expect_sz = sizeof(pkt_v6) + 40; /* Test grow with 40 bytes */
 	topts.data_in = &pkt_v6;
 	topts.data_size_in = sizeof(pkt_v6);
+	topts.data_size_out = sizeof(buf);
 	err = bpf_prog_test_run_opts(prog_fd, &topts);
 	ASSERT_OK(err, "ipv6");
 	ASSERT_EQ(topts.retval, XDP_TX, "ipv6 retval");
-- 
2.30.2

[PATCH bpf-next v4 6/6] selftest/bpf: Fix error usage of ASSERT_OK in xdp_adjust_tail.c

[Xu Kuohai]

From: Xu Kuohai <xukuohai@huawei.com>

xdp_adjust_tail.c calls ASSERT_OK() to check the return value of
bpf_prog_test_load(), but the condition is not correct. Fix it.

Fixes: 791cad025051 ("bpf: selftests: Get rid of CHECK macro in xdp_adjust_tail.c")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
---
 tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
index 009ee37607df..39973ea1ce43 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
@@ -18,7 +18,7 @@ static void test_xdp_adjust_tail_shrink(void)
 	);
 
 	err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
-	if (ASSERT_OK(err, "test_xdp_adjust_tail_shrink"))
+	if (!ASSERT_OK(err, "test_xdp_adjust_tail_shrink"))
 		return;
 
 	err = bpf_prog_test_run_opts(prog_fd, &topts);
@@ -53,7 +53,7 @@ static void test_xdp_adjust_tail_grow(void)
 	);
 
 	err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
-	if (ASSERT_OK(err, "test_xdp_adjust_tail_grow"))
+	if (!ASSERT_OK(err, "test_xdp_adjust_tail_grow"))
 		return;
 
 	err = bpf_prog_test_run_opts(prog_fd, &topts);
@@ -90,7 +90,7 @@ static void test_xdp_adjust_tail_grow2(void)
 	);
 
 	err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
-	if (ASSERT_OK(err, "test_xdp_adjust_tail_grow"))
+	if (!ASSERT_OK(err, "test_xdp_adjust_tail_grow"))
 		return;
 
 	/* Test case-64 */
-- 
2.30.2

Re: [PATCH bpf-next v4 5/6] selftests/bpf: Fix error failure of case test_xdp_adjust_tail_grow

[Martin KaFai Lau]

On 10/11/22 5:01 AM, Xu Kuohai wrote:
> From: Xu Kuohai <xukuohai@huawei.com>
> 
> test_xdp_adjust_tail_grow failed with ipv6:
>    test_xdp_adjust_tail_grow:FAIL:ipv6 unexpected error: -28 (errno 28)
> 
> The reason is that this test case tests ipv4 before ipv6, and when ipv4
> test finished, topts.data_size_out was set to 54, which is smaller than the
> ipv6 output data size 114, so ipv6 test fails with NOSPC error.
> 
> Fix it by reset topts.data_size_out to sizeof(buf) before testing ipv6.
> 
> Fixes: 04fcb5f9a104 ("selftests/bpf: Migrate from bpf_prog_test_run")
> Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
> ---
>   tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
> index 9b9cf8458adf..009ee37607df 100644
> --- a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
> +++ b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
> @@ -63,6 +63,7 @@ static void test_xdp_adjust_tail_grow(void)
>   	expect_sz = sizeof(pkt_v6) + 40; /* Test grow with 40 bytes */
>   	topts.data_in = &pkt_v6;
>   	topts.data_size_in = sizeof(pkt_v6);
> +	topts.data_size_out = sizeof(buf);

lgtm but how was it working before... weird.

>   	err = bpf_prog_test_run_opts(prog_fd, &topts);
>   	ASSERT_OK(err, "ipv6");
>   	ASSERT_EQ(topts.retval, XDP_TX, "ipv6 retval");

Re: [PATCH bpf-next v4 6/6] selftest/bpf: Fix error usage of ASSERT_OK in xdp_adjust_tail.c

[Martin KaFai Lau]

On 10/11/22 5:01 AM, Xu Kuohai wrote:
> From: Xu Kuohai <xukuohai@huawei.com>
> 
> xdp_adjust_tail.c calls ASSERT_OK() to check the return value of
> bpf_prog_test_load(), but the condition is not correct. Fix it.
> 
> Fixes: 791cad025051 ("bpf: selftests: Get rid of CHECK macro in xdp_adjust_tail.c")
> Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
> ---
>   tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
> index 009ee37607df..39973ea1ce43 100644
> --- a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
> +++ b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
> @@ -18,7 +18,7 @@ static void test_xdp_adjust_tail_shrink(void)
>   	);
>   
>   	err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
> -	if (ASSERT_OK(err, "test_xdp_adjust_tail_shrink"))
> +	if (!ASSERT_OK(err, "test_xdp_adjust_tail_shrink"))
>   		return;
>   
>   	err = bpf_prog_test_run_opts(prog_fd, &topts);
> @@ -53,7 +53,7 @@ static void test_xdp_adjust_tail_grow(void)
>   	);
>   
>   	err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
> -	if (ASSERT_OK(err, "test_xdp_adjust_tail_grow"))
> +	if (!ASSERT_OK(err, "test_xdp_adjust_tail_grow"))

Ouch... ic.  It is why this test has been passing.


>   		return;
>   
>   	err = bpf_prog_test_run_opts(prog_fd, &topts);
> @@ -90,7 +90,7 @@ static void test_xdp_adjust_tail_grow2(void)
>   	);
>   
>   	err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
> -	if (ASSERT_OK(err, "test_xdp_adjust_tail_grow"))
> +	if (!ASSERT_OK(err, "test_xdp_adjust_tail_grow"))
>   		return;
>   
>   	/* Test case-64 */

Re: [PATCH bpf-next v4 0/6] Fix bugs found by ASAN when running selftests

[Martin KaFai Lau]

On 10/11/22 5:01 AM, Xu Kuohai wrote:
> From: Xu Kuohai <xukuohai@huawei.com>
> 
> This series fixes bugs found by ASAN when running bpf selftests on arm64

Overall lgtm.

Acked-by: Martin KaFai Lau <martin.lau@kernel.org>

Re: [PATCH bpf-next v4 6/6] selftest/bpf: Fix error usage of ASSERT_OK in xdp_adjust_tail.c

[Xu Kuohai]

On 10/13/2022 7:26 AM, Martin KaFai Lau wrote:
> On 10/11/22 5:01 AM, Xu Kuohai wrote:
>> From: Xu Kuohai <xukuohai@huawei.com>
>>
>> xdp_adjust_tail.c calls ASSERT_OK() to check the return value of
>> bpf_prog_test_load(), but the condition is not correct. Fix it.
>>
>> Fixes: 791cad025051 ("bpf: selftests: Get rid of CHECK macro in xdp_adjust_tail.c")
>> Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
>> ---
>>   tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c | 6 +++---
>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
>> index 009ee37607df..39973ea1ce43 100644
>> --- a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
>> +++ b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
>> @@ -18,7 +18,7 @@ static void test_xdp_adjust_tail_shrink(void)
>>       );
>>       err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
>> -    if (ASSERT_OK(err, "test_xdp_adjust_tail_shrink"))
>> +    if (!ASSERT_OK(err, "test_xdp_adjust_tail_shrink"))
>>           return;
>>       err = bpf_prog_test_run_opts(prog_fd, &topts);
>> @@ -53,7 +53,7 @@ static void test_xdp_adjust_tail_grow(void)
>>       );
>>       err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
>> -    if (ASSERT_OK(err, "test_xdp_adjust_tail_grow"))
>> +    if (!ASSERT_OK(err, "test_xdp_adjust_tail_grow"))
> 
> Ouch... ic.  It is why this test has been passing.
> 

Well, it's because the value of err is zero, so ASSERT_OK passed.

> 
>>           return;
>>       err = bpf_prog_test_run_opts(prog_fd, &topts);
>> @@ -90,7 +90,7 @@ static void test_xdp_adjust_tail_grow2(void)
>>       );
>>       err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
>> -    if (ASSERT_OK(err, "test_xdp_adjust_tail_grow"))
>> +    if (!ASSERT_OK(err, "test_xdp_adjust_tail_grow"))
>>           return;
>>       /* Test case-64 */
> 
> .

Re: [PATCH bpf-next v4 5/6] selftests/bpf: Fix error failure of case test_xdp_adjust_tail_grow

[Xu Kuohai]

On 10/13/2022 7:17 AM, Martin KaFai Lau wrote:
> On 10/11/22 5:01 AM, Xu Kuohai wrote:
>> From: Xu Kuohai <xukuohai@huawei.com>
>>
>> test_xdp_adjust_tail_grow failed with ipv6:
>>    test_xdp_adjust_tail_grow:FAIL:ipv6 unexpected error: -28 (errno 28)
>>
>> The reason is that this test case tests ipv4 before ipv6, and when ipv4
>> test finished, topts.data_size_out was set to 54, which is smaller than the
>> ipv6 output data size 114, so ipv6 test fails with NOSPC error.
>>
>> Fix it by reset topts.data_size_out to sizeof(buf) before testing ipv6.
>>
>> Fixes: 04fcb5f9a104 ("selftests/bpf: Migrate from bpf_prog_test_run")
>> Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
>> ---
>>   tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
>> index 9b9cf8458adf..009ee37607df 100644
>> --- a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
>> +++ b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
>> @@ -63,6 +63,7 @@ static void test_xdp_adjust_tail_grow(void)
>>       expect_sz = sizeof(pkt_v6) + 40; /* Test grow with 40 bytes */
>>       topts.data_in = &pkt_v6;
>>       topts.data_size_in = sizeof(pkt_v6);
>> +    topts.data_size_out = sizeof(buf);
> 
> lgtm but how was it working before... weird.
> 

the test case returns before this line is executed, see patch 6

>>       err = bpf_prog_test_run_opts(prog_fd, &topts);
>>       ASSERT_OK(err, "ipv6");
>>       ASSERT_EQ(topts.retval, XDP_TX, "ipv6 retval");
> 
> .

Re: [PATCH bpf-next v4 2/6] libbpf: Fix memory leak in parse_usdt_arg()

[Andrii Nakryiko]

On Tue, Oct 11, 2022 at 4:43 AM Xu Kuohai <xukuohai@huaweicloud.com> wrote:
>
> From: Xu Kuohai <xukuohai@huawei.com>
>
> In the arm64 version of parse_usdt_arg(), when sscanf returns 2, reg_name
> is allocated but not freed. Fix it.
>
> Fixes: 0f8619929c57 ("libbpf: Usdt aarch64 arg parsing support")
> Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
> ---
>  tools/lib/bpf/usdt.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
>
> diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c
> index e83b497c2245..49f3c3b7f609 100644
> --- a/tools/lib/bpf/usdt.c
> +++ b/tools/lib/bpf/usdt.c
> @@ -1348,25 +1348,23 @@ static int calc_pt_regs_off(const char *reg_name)
>
>  static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)
>  {
> -       char *reg_name = NULL;
> +       char reg_name[16];
>         int arg_sz, len, reg_off;
>         long off;
>
> -       if (sscanf(arg_str, " %d @ \[ %m[a-z0-9], %ld ] %n", &arg_sz, &reg_name, &off, &len) == 3) {
> +       if (sscanf(arg_str, " %d @ \[ %15[a-z0-9], %ld ] %n", &arg_sz, reg_name, &off, &len) == 3) {

It would be nice to do the same change for other architectures where
it makes sense and avoid having to deal with unnecessary memory
allocations. Please send follow up patches with similar changes for
other implementations of parse_usdt_arg. Thanks.


>                 /* Memory dereference case, e.g., -4@[sp, 96] */
>                 arg->arg_type = USDT_ARG_REG_DEREF;
>                 arg->val_off = off;
>                 reg_off = calc_pt_regs_off(reg_name);
> -               free(reg_name);
>                 if (reg_off < 0)
>                         return reg_off;
>                 arg->reg_off = reg_off;
> -       } else if (sscanf(arg_str, " %d @ \[ %m[a-z0-9] ] %n", &arg_sz, &reg_name, &len) == 2) {
> +       } else if (sscanf(arg_str, " %d @ \[ %15[a-z0-9] ] %n", &arg_sz, reg_name, &len) == 2) {
>                 /* Memory dereference case, e.g., -4@[sp] */
>                 arg->arg_type = USDT_ARG_REG_DEREF;
>                 arg->val_off = 0;
>                 reg_off = calc_pt_regs_off(reg_name);
> -               free(reg_name);
>                 if (reg_off < 0)
>                         return reg_off;
>                 arg->reg_off = reg_off;
> @@ -1375,12 +1373,11 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
>                 arg->arg_type = USDT_ARG_CONST;
>                 arg->val_off = off;
>                 arg->reg_off = 0;
> -       } else if (sscanf(arg_str, " %d @ %m[a-z0-9] %n", &arg_sz, &reg_name, &len) == 2) {
> +       } else if (sscanf(arg_str, " %d @ %15[a-z0-9] %n", &arg_sz, reg_name, &len) == 2) {
>                 /* Register read case, e.g., -8@x4 */
>                 arg->arg_type = USDT_ARG_REG;
>                 arg->val_off = 0;
>                 reg_off = calc_pt_regs_off(reg_name);
> -               free(reg_name);
>                 if (reg_off < 0)
>                         return reg_off;
>                 arg->reg_off = reg_off;
> --
> 2.30.2
>

Re: [PATCH bpf-next v4 0/6] Fix bugs found by ASAN when running selftests

[patchwork-bot+netdevbpf]

Hello:

This series was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Tue, 11 Oct 2022 08:01:02 -0400 you wrote:
> From: Xu Kuohai <xukuohai@huawei.com>
> 
> This series fixes bugs found by ASAN when running bpf selftests on arm64.
> 
> v4:
> - Address Andrii's suggestions
> 
> [...]

Here is the summary with links:
  - [bpf-next,v4,1/6] libbpf: Fix use-after-free in btf_dump_name_dups
    https://git.kernel.org/bpf/bpf-next/c/02c1e5b0bbb8
  - [bpf-next,v4,2/6] libbpf: Fix memory leak in parse_usdt_arg()
    https://git.kernel.org/bpf/bpf-next/c/cd168cc6f685
  - [bpf-next,v4,3/6] selftests/bpf: Fix memory leak caused by not destroying skeleton
    https://git.kernel.org/bpf/bpf-next/c/fbca16071678
  - [bpf-next,v4,4/6] selftest/bpf: Fix memory leak in kprobe_multi_test
    https://git.kernel.org/bpf/bpf-next/c/159c69121102
  - [bpf-next,v4,5/6] selftests/bpf: Fix error failure of case test_xdp_adjust_tail_grow
    https://git.kernel.org/bpf/bpf-next/c/496848b47126
  - [bpf-next,v4,6/6] selftest/bpf: Fix error usage of ASSERT_OK in xdp_adjust_tail.c
    https://git.kernel.org/bpf/bpf-next/c/cafecc0e3df3

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

Re: [PATCH bpf-next v4 2/6] libbpf: Fix memory leak in parse_usdt_arg()

[Xu Kuohai]

On 10/13/2022 11:47 PM, Andrii Nakryiko wrote:
> On Tue, Oct 11, 2022 at 4:43 AM Xu Kuohai <xukuohai@huaweicloud.com> wrote:
>>
>> From: Xu Kuohai <xukuohai@huawei.com>
>>
>> In the arm64 version of parse_usdt_arg(), when sscanf returns 2, reg_name
>> is allocated but not freed. Fix it.
>>
>> Fixes: 0f8619929c57 ("libbpf: Usdt aarch64 arg parsing support")
>> Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
>> ---
>>   tools/lib/bpf/usdt.c | 11 ++++-------
>>   1 file changed, 4 insertions(+), 7 deletions(-)
>>
>> diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c
>> index e83b497c2245..49f3c3b7f609 100644
>> --- a/tools/lib/bpf/usdt.c
>> +++ b/tools/lib/bpf/usdt.c
>> @@ -1348,25 +1348,23 @@ static int calc_pt_regs_off(const char *reg_name)
>>
>>   static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)
>>   {
>> -       char *reg_name = NULL;
>> +       char reg_name[16];
>>          int arg_sz, len, reg_off;
>>          long off;
>>
>> -       if (sscanf(arg_str, " %d @ \[ %m[a-z0-9], %ld ] %n", &arg_sz, &reg_name, &off, &len) == 3) {
>> +       if (sscanf(arg_str, " %d @ \[ %15[a-z0-9], %ld ] %n", &arg_sz, reg_name, &off, &len) == 3) {
> 
> It would be nice to do the same change for other architectures where
> it makes sense and avoid having to deal with unnecessary memory
> allocations. Please send follow up patches with similar changes for
> other implementations of parse_usdt_arg. Thanks.
>

ok, will do

> 
>>                  /* Memory dereference case, e.g., -4@[sp, 96] */
>>                  arg->arg_type = USDT_ARG_REG_DEREF;
>>                  arg->val_off = off;
>>                  reg_off = calc_pt_regs_off(reg_name);
>> -               free(reg_name);
>>                  if (reg_off < 0)
>>                          return reg_off;
>>                  arg->reg_off = reg_off;
>> -       } else if (sscanf(arg_str, " %d @ \[ %m[a-z0-9] ] %n", &arg_sz, &reg_name, &len) == 2) {
>> +       } else if (sscanf(arg_str, " %d @ \[ %15[a-z0-9] ] %n", &arg_sz, reg_name, &len) == 2) {
>>                  /* Memory dereference case, e.g., -4@[sp] */
>>                  arg->arg_type = USDT_ARG_REG_DEREF;
>>                  arg->val_off = 0;
>>                  reg_off = calc_pt_regs_off(reg_name);
>> -               free(reg_name);
>>                  if (reg_off < 0)
>>                          return reg_off;
>>                  arg->reg_off = reg_off;
>> @@ -1375,12 +1373,11 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
>>                  arg->arg_type = USDT_ARG_CONST;
>>                  arg->val_off = off;
>>                  arg->reg_off = 0;
>> -       } else if (sscanf(arg_str, " %d @ %m[a-z0-9] %n", &arg_sz, &reg_name, &len) == 2) {
>> +       } else if (sscanf(arg_str, " %d @ %15[a-z0-9] %n", &arg_sz, reg_name, &len) == 2) {
>>                  /* Register read case, e.g., -8@x4 */
>>                  arg->arg_type = USDT_ARG_REG;
>>                  arg->val_off = 0;
>>                  reg_off = calc_pt_regs_off(reg_name);
>> -               free(reg_name);
>>                  if (reg_off < 0)
>>                          return reg_off;
>>                  arg->reg_off = reg_off;
>> --
>> 2.30.2
>>
> .