libbpf: Streamline bpf_attr and perf_event_attr initialization

Make sure that entire libbpf code base is initializing bpf_attr and
perf_event_attr with memset(0). Also for bpf_attr make sure we
clear and pass to kernel only relevant parts of bpf_attr. bpf_attr is
a huge union of independent sub-command attributes, so there is no need
to clear and pass entire union bpf_attr, which over time grows quite
a lot and for most commands this growth is completely irrelevant.

Few cases where we were relying on compiler initialization of BPF UAPI
structs (like bpf_prog_info, bpf_map_info, etc) with `= {};` were
switched to memset(0) pattern for future-proofing.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/bpf/20220816001929.369487-3-andrii@kernel.org

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 575867d..e3a0bd7 100644 (file)
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -105,7 +105,7 @@ int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts)
  */
 int probe_memcg_account(void)
 {
-       const size_t prog_load_attr_sz = offsetofend(union bpf_attr, attach_btf_obj_fd);
+       const size_t attr_sz = offsetofend(union bpf_attr, attach_btf_obj_fd);
        struct bpf_insn insns[] = {
                BPF_EMIT_CALL(BPF_FUNC_ktime_get_coarse_ns),
                BPF_EXIT_INSN(),
@@ -115,13 +115,13 @@ int probe_memcg_account(void)
        int prog_fd;
 
        /* attempt loading freplace trying to use custom BTF */
-       memset(&attr, 0, prog_load_attr_sz);
+       memset(&attr, 0, attr_sz);
        attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
        attr.insns = ptr_to_u64(insns);
        attr.insn_cnt = insn_cnt;
        attr.license = ptr_to_u64("GPL");
 
-       prog_fd = sys_bpf_fd(BPF_PROG_LOAD, &attr, prog_load_attr_sz);
+       prog_fd = sys_bpf_fd(BPF_PROG_LOAD, &attr, attr_sz);
        if (prog_fd >= 0) {
                close(prog_fd);
                return 1;
@@ -232,6 +232,7 @@ int bpf_prog_load(enum bpf_prog_type prog_type,
                  const struct bpf_insn *insns, size_t insn_cnt,
                  const struct bpf_prog_load_opts *opts)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, fd_array);
        void *finfo = NULL, *linfo = NULL;
        const char *func_info, *line_info;
        __u32 log_size, log_level, attach_prog_fd, attach_btf_obj_fd;
@@ -251,7 +252,7 @@ int bpf_prog_load(enum bpf_prog_type prog_type,
        if (attempts == 0)
                attempts = PROG_LOAD_ATTEMPTS;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
 
        attr.prog_type = prog_type;
        attr.expected_attach_type = OPTS_GET(opts, expected_attach_type, 0);
@@ -314,7 +315,7 @@ int bpf_prog_load(enum bpf_prog_type prog_type,
                attr.log_level = log_level;
        }
 
-       fd = sys_bpf_prog_load(&attr, sizeof(attr), attempts);
+       fd = sys_bpf_prog_load(&attr, attr_sz, attempts);
        if (fd >= 0)
                return fd;
 
@@ -354,7 +355,7 @@ int bpf_prog_load(enum bpf_prog_type prog_type,
                        break;
                }
 
-               fd = sys_bpf_prog_load(&attr, sizeof(attr), attempts);
+               fd = sys_bpf_prog_load(&attr, attr_sz, attempts);
                if (fd >= 0)
                        goto done;
        }
@@ -368,7 +369,7 @@ int bpf_prog_load(enum bpf_prog_type prog_type,
                attr.log_size = log_size;
                attr.log_level = 1;
 
-               fd = sys_bpf_prog_load(&attr, sizeof(attr), attempts);
+               fd = sys_bpf_prog_load(&attr, attr_sz, attempts);
        }
 done:
        /* free() doesn't affect errno, so we don't need to restore it */
@@ -380,127 +381,136 @@ done:
 int bpf_map_update_elem(int fd, const void *key, const void *value,
                        __u64 flags)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, flags);
        union bpf_attr attr;
        int ret;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.map_fd = fd;
        attr.key = ptr_to_u64(key);
        attr.value = ptr_to_u64(value);
        attr.flags = flags;
 
-       ret = sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, attr_sz);
        return libbpf_err_errno(ret);
 }
 
 int bpf_map_lookup_elem(int fd, const void *key, void *value)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, flags);
        union bpf_attr attr;
        int ret;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.map_fd = fd;
        attr.key = ptr_to_u64(key);
        attr.value = ptr_to_u64(value);
 
-       ret = sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, attr_sz);
        return libbpf_err_errno(ret);
 }
 
 int bpf_map_lookup_elem_flags(int fd, const void *key, void *value, __u64 flags)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, flags);
        union bpf_attr attr;
        int ret;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.map_fd = fd;
        attr.key = ptr_to_u64(key);
        attr.value = ptr_to_u64(value);
        attr.flags = flags;
 
-       ret = sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, attr_sz);
        return libbpf_err_errno(ret);
 }
 
 int bpf_map_lookup_and_delete_elem(int fd, const void *key, void *value)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, flags);
        union bpf_attr attr;
        int ret;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.map_fd = fd;
        attr.key = ptr_to_u64(key);
        attr.value = ptr_to_u64(value);
 
-       ret = sys_bpf(BPF_MAP_LOOKUP_AND_DELETE_ELEM, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_MAP_LOOKUP_AND_DELETE_ELEM, &attr, attr_sz);
        return libbpf_err_errno(ret);
 }
 
 int bpf_map_lookup_and_delete_elem_flags(int fd, const void *key, void *value, __u64 flags)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, flags);
        union bpf_attr attr;
        int ret;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.map_fd = fd;
        attr.key = ptr_to_u64(key);
        attr.value = ptr_to_u64(value);
        attr.flags = flags;
 
-       ret = sys_bpf(BPF_MAP_LOOKUP_AND_DELETE_ELEM, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_MAP_LOOKUP_AND_DELETE_ELEM, &attr, attr_sz);
        return libbpf_err_errno(ret);
 }
 
 int bpf_map_delete_elem(int fd, const void *key)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, flags);
        union bpf_attr attr;
        int ret;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.map_fd = fd;
        attr.key = ptr_to_u64(key);
 
-       ret = sys_bpf(BPF_MAP_DELETE_ELEM, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_MAP_DELETE_ELEM, &attr, attr_sz);
        return libbpf_err_errno(ret);
 }
 
 int bpf_map_delete_elem_flags(int fd, const void *key, __u64 flags)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, flags);
        union bpf_attr attr;
        int ret;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.map_fd = fd;
        attr.key = ptr_to_u64(key);
        attr.flags = flags;
 
-       ret = sys_bpf(BPF_MAP_DELETE_ELEM, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_MAP_DELETE_ELEM, &attr, attr_sz);
        return libbpf_err_errno(ret);
 }
 
 int bpf_map_get_next_key(int fd, const void *key, void *next_key)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, next_key);
        union bpf_attr attr;
        int ret;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.map_fd = fd;
        attr.key = ptr_to_u64(key);
        attr.next_key = ptr_to_u64(next_key);
 
-       ret = sys_bpf(BPF_MAP_GET_NEXT_KEY, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_MAP_GET_NEXT_KEY, &attr, attr_sz);
        return libbpf_err_errno(ret);
 }
 
 int bpf_map_freeze(int fd)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, map_fd);
        union bpf_attr attr;
        int ret;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.map_fd = fd;
 
-       ret = sys_bpf(BPF_MAP_FREEZE, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_MAP_FREEZE, &attr, attr_sz);
        return libbpf_err_errno(ret);
 }
 
@@ -509,13 +519,14 @@ static int bpf_map_batch_common(int cmd, int fd, void  *in_batch,
                                __u32 *count,
                                const struct bpf_map_batch_opts *opts)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, batch);
        union bpf_attr attr;
        int ret;
 
        if (!OPTS_VALID(opts, bpf_map_batch_opts))
                return libbpf_err(-EINVAL);
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.batch.map_fd = fd;
        attr.batch.in_batch = ptr_to_u64(in_batch);
        attr.batch.out_batch = ptr_to_u64(out_batch);
@@ -525,7 +536,7 @@ static int bpf_map_batch_common(int cmd, int fd, void  *in_batch,
        attr.batch.elem_flags  = OPTS_GET(opts, elem_flags, 0);
        attr.batch.flags = OPTS_GET(opts, flags, 0);
 
-       ret = sys_bpf(cmd, &attr, sizeof(attr));
+       ret = sys_bpf(cmd, &attr, attr_sz);
        *count = attr.batch.count;
 
        return libbpf_err_errno(ret);
@@ -564,14 +575,15 @@ int bpf_map_update_batch(int fd, const void *keys, const void *values, __u32 *co
 
 int bpf_obj_pin(int fd, const char *pathname)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, file_flags);
        union bpf_attr attr;
        int ret;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.pathname = ptr_to_u64((void *)pathname);
        attr.bpf_fd = fd;
 
-       ret = sys_bpf(BPF_OBJ_PIN, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_OBJ_PIN, &attr, attr_sz);
        return libbpf_err_errno(ret);
 }
 
@@ -582,17 +594,18 @@ int bpf_obj_get(const char *pathname)
 
 int bpf_obj_get_opts(const char *pathname, const struct bpf_obj_get_opts *opts)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, file_flags);
        union bpf_attr attr;
        int fd;
 
        if (!OPTS_VALID(opts, bpf_obj_get_opts))
                return libbpf_err(-EINVAL);
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.pathname = ptr_to_u64((void *)pathname);
        attr.file_flags = OPTS_GET(opts, file_flags, 0);
 
-       fd = sys_bpf_fd(BPF_OBJ_GET, &attr, sizeof(attr));
+       fd = sys_bpf_fd(BPF_OBJ_GET, &attr, attr_sz);
        return libbpf_err_errno(fd);
 }
 
@@ -610,20 +623,21 @@ int bpf_prog_attach_opts(int prog_fd, int target_fd,
                          enum bpf_attach_type type,
                          const struct bpf_prog_attach_opts *opts)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, replace_bpf_fd);
        union bpf_attr attr;
        int ret;
 
        if (!OPTS_VALID(opts, bpf_prog_attach_opts))
                return libbpf_err(-EINVAL);
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.target_fd     = target_fd;
        attr.attach_bpf_fd = prog_fd;
        attr.attach_type   = type;
        attr.attach_flags  = OPTS_GET(opts, flags, 0);
        attr.replace_bpf_fd = OPTS_GET(opts, replace_prog_fd, 0);
 
-       ret = sys_bpf(BPF_PROG_ATTACH, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_PROG_ATTACH, &attr, attr_sz);
        return libbpf_err_errno(ret);
 }
 
@@ -634,28 +648,30 @@ int bpf_prog_attach_xattr(int prog_fd, int target_fd,
 
 int bpf_prog_detach(int target_fd, enum bpf_attach_type type)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, replace_bpf_fd);
        union bpf_attr attr;
        int ret;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.target_fd   = target_fd;
        attr.attach_type = type;
 
-       ret = sys_bpf(BPF_PROG_DETACH, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_PROG_DETACH, &attr, attr_sz);
        return libbpf_err_errno(ret);
 }
 
 int bpf_prog_detach2(int prog_fd, int target_fd, enum bpf_attach_type type)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, replace_bpf_fd);
        union bpf_attr attr;
        int ret;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.target_fd   = target_fd;
        attr.attach_bpf_fd = prog_fd;
        attr.attach_type = type;
 
-       ret = sys_bpf(BPF_PROG_DETACH, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_PROG_DETACH, &attr, attr_sz);
        return libbpf_err_errno(ret);
 }
 
@@ -663,6 +679,7 @@ int bpf_link_create(int prog_fd, int target_fd,
                    enum bpf_attach_type attach_type,
                    const struct bpf_link_create_opts *opts)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, link_create);
        __u32 target_btf_id, iter_info_len;
        union bpf_attr attr;
        int fd, err;
@@ -681,7 +698,7 @@ int bpf_link_create(int prog_fd, int target_fd,
                        return libbpf_err(-EINVAL);
        }
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.link_create.prog_fd = prog_fd;
        attr.link_create.target_fd = target_fd;
        attr.link_create.attach_type = attach_type;
@@ -725,7 +742,7 @@ int bpf_link_create(int prog_fd, int target_fd,
                break;
        }
 proceed:
-       fd = sys_bpf_fd(BPF_LINK_CREATE, &attr, sizeof(attr));
+       fd = sys_bpf_fd(BPF_LINK_CREATE, &attr, attr_sz);
        if (fd >= 0)
                return fd;
        /* we'll get EINVAL if LINK_CREATE doesn't support attaching fentry
@@ -761,44 +778,47 @@ proceed:
 
 int bpf_link_detach(int link_fd)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, link_detach);
        union bpf_attr attr;
        int ret;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.link_detach.link_fd = link_fd;
 
-       ret = sys_bpf(BPF_LINK_DETACH, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_LINK_DETACH, &attr, attr_sz);
        return libbpf_err_errno(ret);
 }
 
 int bpf_link_update(int link_fd, int new_prog_fd,
                    const struct bpf_link_update_opts *opts)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, link_update);
        union bpf_attr attr;
        int ret;
 
        if (!OPTS_VALID(opts, bpf_link_update_opts))
                return libbpf_err(-EINVAL);
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.link_update.link_fd = link_fd;
        attr.link_update.new_prog_fd = new_prog_fd;
        attr.link_update.flags = OPTS_GET(opts, flags, 0);
        attr.link_update.old_prog_fd = OPTS_GET(opts, old_prog_fd, 0);
 
-       ret = sys_bpf(BPF_LINK_UPDATE, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_LINK_UPDATE, &attr, attr_sz);
        return libbpf_err_errno(ret);
 }
 
 int bpf_iter_create(int link_fd)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, iter_create);
        union bpf_attr attr;
        int fd;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.iter_create.link_fd = link_fd;
 
-       fd = sys_bpf_fd(BPF_ITER_CREATE, &attr, sizeof(attr));
+       fd = sys_bpf_fd(BPF_ITER_CREATE, &attr, attr_sz);
        return libbpf_err_errno(fd);
 }
 
@@ -806,13 +826,14 @@ int bpf_prog_query_opts(int target_fd,
                        enum bpf_attach_type type,
                        struct bpf_prog_query_opts *opts)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, query);
        union bpf_attr attr;
        int ret;
 
        if (!OPTS_VALID(opts, bpf_prog_query_opts))
                return libbpf_err(-EINVAL);
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
 
        attr.query.target_fd    = target_fd;
        attr.query.attach_type  = type;
@@ -821,7 +842,7 @@ int bpf_prog_query_opts(int target_fd,
        attr.query.prog_ids     = ptr_to_u64(OPTS_GET(opts, prog_ids, NULL));
        attr.query.prog_attach_flags = ptr_to_u64(OPTS_GET(opts, prog_attach_flags, NULL));
 
-       ret = sys_bpf(BPF_PROG_QUERY, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_PROG_QUERY, &attr, attr_sz);
 
        OPTS_SET(opts, attach_flags, attr.query.attach_flags);
        OPTS_SET(opts, prog_cnt, attr.query.prog_cnt);
@@ -850,13 +871,14 @@ int bpf_prog_query(int target_fd, enum bpf_attach_type type, __u32 query_flags,
 
 int bpf_prog_test_run_opts(int prog_fd, struct bpf_test_run_opts *opts)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, test);
        union bpf_attr attr;
        int ret;
 
        if (!OPTS_VALID(opts, bpf_test_run_opts))
                return libbpf_err(-EINVAL);
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.test.prog_fd = prog_fd;
        attr.test.batch_size = OPTS_GET(opts, batch_size, 0);
        attr.test.cpu = OPTS_GET(opts, cpu, 0);
@@ -872,7 +894,7 @@ int bpf_prog_test_run_opts(int prog_fd, struct bpf_test_run_opts *opts)
        attr.test.data_in = ptr_to_u64(OPTS_GET(opts, data_in, NULL));
        attr.test.data_out = ptr_to_u64(OPTS_GET(opts, data_out, NULL));
 
-       ret = sys_bpf(BPF_PROG_TEST_RUN, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_PROG_TEST_RUN, &attr, attr_sz);
 
        OPTS_SET(opts, data_size_out, attr.test.data_size_out);
        OPTS_SET(opts, ctx_size_out, attr.test.ctx_size_out);
@@ -884,13 +906,14 @@ int bpf_prog_test_run_opts(int prog_fd, struct bpf_test_run_opts *opts)
 
 static int bpf_obj_get_next_id(__u32 start_id, __u32 *next_id, int cmd)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, open_flags);
        union bpf_attr attr;
        int err;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.start_id = start_id;
 
-       err = sys_bpf(cmd, &attr, sizeof(attr));
+       err = sys_bpf(cmd, &attr, attr_sz);
        if (!err)
                *next_id = attr.next_id;
 
@@ -919,80 +942,84 @@ int bpf_link_get_next_id(__u32 start_id, __u32 *next_id)
 
 int bpf_prog_get_fd_by_id(__u32 id)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, open_flags);
        union bpf_attr attr;
        int fd;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.prog_id = id;
 
-       fd = sys_bpf_fd(BPF_PROG_GET_FD_BY_ID, &attr, sizeof(attr));
+       fd = sys_bpf_fd(BPF_PROG_GET_FD_BY_ID, &attr, attr_sz);
        return libbpf_err_errno(fd);
 }
 
 int bpf_map_get_fd_by_id(__u32 id)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, open_flags);
        union bpf_attr attr;
        int fd;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.map_id = id;
 
-       fd = sys_bpf_fd(BPF_MAP_GET_FD_BY_ID, &attr, sizeof(attr));
+       fd = sys_bpf_fd(BPF_MAP_GET_FD_BY_ID, &attr, attr_sz);
        return libbpf_err_errno(fd);
 }
 
 int bpf_btf_get_fd_by_id(__u32 id)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, open_flags);
        union bpf_attr attr;
        int fd;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.btf_id = id;
 
-       fd = sys_bpf_fd(BPF_BTF_GET_FD_BY_ID, &attr, sizeof(attr));
+       fd = sys_bpf_fd(BPF_BTF_GET_FD_BY_ID, &attr, attr_sz);
        return libbpf_err_errno(fd);
 }
 
 int bpf_link_get_fd_by_id(__u32 id)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, open_flags);
        union bpf_attr attr;
        int fd;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.link_id = id;
 
-       fd = sys_bpf_fd(BPF_LINK_GET_FD_BY_ID, &attr, sizeof(attr));
+       fd = sys_bpf_fd(BPF_LINK_GET_FD_BY_ID, &attr, attr_sz);
        return libbpf_err_errno(fd);
 }
 
 int bpf_obj_get_info_by_fd(int bpf_fd, void *info, __u32 *info_len)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, info);
        union bpf_attr attr;
        int err;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.info.bpf_fd = bpf_fd;
        attr.info.info_len = *info_len;
        attr.info.info = ptr_to_u64(info);
 
-       err = sys_bpf(BPF_OBJ_GET_INFO_BY_FD, &attr, sizeof(attr));
-
+       err = sys_bpf(BPF_OBJ_GET_INFO_BY_FD, &attr, attr_sz);
        if (!err)
                *info_len = attr.info.info_len;
-
        return libbpf_err_errno(err);
 }
 
 int bpf_raw_tracepoint_open(const char *name, int prog_fd)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, raw_tracepoint);
        union bpf_attr attr;
        int fd;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.raw_tracepoint.name = ptr_to_u64(name);
        attr.raw_tracepoint.prog_fd = prog_fd;
 
-       fd = sys_bpf_fd(BPF_RAW_TRACEPOINT_OPEN, &attr, sizeof(attr));
+       fd = sys_bpf_fd(BPF_RAW_TRACEPOINT_OPEN, &attr, attr_sz);
        return libbpf_err_errno(fd);
 }
 
@@ -1048,16 +1075,18 @@ int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf, __u32 *buf_len,
                      __u32 *prog_id, __u32 *fd_type, __u64 *probe_offset,
                      __u64 *probe_addr)
 {
-       union bpf_attr attr = {};
+       const size_t attr_sz = offsetofend(union bpf_attr, task_fd_query);
+       union bpf_attr attr;
        int err;
 
+       memset(&attr, 0, attr_sz);
        attr.task_fd_query.pid = pid;
        attr.task_fd_query.fd = fd;
        attr.task_fd_query.flags = flags;
        attr.task_fd_query.buf = ptr_to_u64(buf);
        attr.task_fd_query.buf_len = *buf_len;
 
-       err = sys_bpf(BPF_TASK_FD_QUERY, &attr, sizeof(attr));
+       err = sys_bpf(BPF_TASK_FD_QUERY, &attr, attr_sz);
 
        *buf_len = attr.task_fd_query.buf_len;
        *prog_id = attr.task_fd_query.prog_id;
@@ -1070,30 +1099,32 @@ int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf, __u32 *buf_len,
 
 int bpf_enable_stats(enum bpf_stats_type type)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, enable_stats);
        union bpf_attr attr;
        int fd;
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.enable_stats.type = type;
 
-       fd = sys_bpf_fd(BPF_ENABLE_STATS, &attr, sizeof(attr));
+       fd = sys_bpf_fd(BPF_ENABLE_STATS, &attr, attr_sz);
        return libbpf_err_errno(fd);
 }
 
 int bpf_prog_bind_map(int prog_fd, int map_fd,
                      const struct bpf_prog_bind_opts *opts)
 {
+       const size_t attr_sz = offsetofend(union bpf_attr, prog_bind_map);
        union bpf_attr attr;
        int ret;
 
        if (!OPTS_VALID(opts, bpf_prog_bind_opts))
                return libbpf_err(-EINVAL);
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, attr_sz);
        attr.prog_bind_map.prog_fd = prog_fd;
        attr.prog_bind_map.map_fd = map_fd;
        attr.prog_bind_map.flags = OPTS_GET(opts, flags, 0);
 
-       ret = sys_bpf(BPF_PROG_BIND_MAP, &attr, sizeof(attr));
+       ret = sys_bpf(BPF_PROG_BIND_MAP, &attr, attr_sz);
        return libbpf_err_errno(ret);
 }

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 146d355..21fc3fc 100644 (file)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4287,11 +4287,12 @@ int bpf_map__set_autocreate(struct bpf_map *map, bool autocreate)
 
 int bpf_map__reuse_fd(struct bpf_map *map, int fd)
 {
-       struct bpf_map_info info = {};
+       struct bpf_map_info info;
        __u32 len = sizeof(info), name_len;
        int new_fd, err;
        char *new_name;
 
+       memset(&info, 0, len);
        err = bpf_obj_get_info_by_fd(fd, &info, &len);
        if (err && errno == EINVAL)
                err = bpf_get_map_info_from_fdinfo(fd, &info);
@@ -4833,13 +4834,12 @@ bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id)
 
 static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd)
 {
-       struct bpf_map_info map_info = {};
+       struct bpf_map_info map_info;
        char msg[STRERR_BUFSIZE];
-       __u32 map_info_len;
+       __u32 map_info_len = sizeof(map_info);
        int err;
 
-       map_info_len = sizeof(map_info);
-
+       memset(&map_info, 0, map_info_len);
        err = bpf_obj_get_info_by_fd(map_fd, &map_info, &map_info_len);
        if (err && errno == EINVAL)
                err = bpf_get_map_info_from_fdinfo(map_fd, &map_info);
@@ -9007,11 +9007,12 @@ int libbpf_find_vmlinux_btf_id(const char *name,
 
 static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd)
 {
-       struct bpf_prog_info info = {};
+       struct bpf_prog_info info;
        __u32 info_len = sizeof(info);
        struct btf *btf;
        int err;
 
+       memset(&info, 0, info_len);
        err = bpf_obj_get_info_by_fd(attach_prog_fd, &info, &info_len);
        if (err) {
                pr_warn("failed bpf_obj_get_info_by_fd for FD %d: %d\n",
@@ -9839,13 +9840,16 @@ static int determine_uprobe_retprobe_bit(void)
 static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
                                 uint64_t offset, int pid, size_t ref_ctr_off)
 {
-       struct perf_event_attr attr = {};
+       const size_t attr_sz = sizeof(struct perf_event_attr);
+       struct perf_event_attr attr;
        char errmsg[STRERR_BUFSIZE];
        int type, pfd;
 
        if (ref_ctr_off >= (1ULL << PERF_UPROBE_REF_CTR_OFFSET_BITS))
                return -EINVAL;
 
+       memset(&attr, 0, attr_sz);
+
        type = uprobe ? determine_uprobe_perf_type()
                      : determine_kprobe_perf_type();
        if (type < 0) {
@@ -9866,7 +9870,7 @@ static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
                }
                attr.config |= 1 << bit;
        }
-       attr.size = sizeof(attr);
+       attr.size = attr_sz;
        attr.type = type;
        attr.config |= (__u64)ref_ctr_off << PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
        attr.config1 = ptr_to_u64(name); /* kprobe_func or uprobe_path */
@@ -9965,7 +9969,8 @@ static int determine_kprobe_perf_type_legacy(const char *probe_name, bool retpro
 static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
                                         const char *kfunc_name, size_t offset, int pid)
 {
-       struct perf_event_attr attr = {};
+       const size_t attr_sz = sizeof(struct perf_event_attr);
+       struct perf_event_attr attr;
        char errmsg[STRERR_BUFSIZE];
        int type, pfd, err;
 
@@ -9984,7 +9989,9 @@ static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
                        libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
                goto err_clean_legacy;
        }
-       attr.size = sizeof(attr);
+
+       memset(&attr, 0, attr_sz);
+       attr.size = attr_sz;
        attr.config = type;
        attr.type = PERF_TYPE_TRACEPOINT;
 
@@ -10441,6 +10448,7 @@ static int determine_uprobe_perf_type_legacy(const char *probe_name, bool retpro
 static int perf_event_uprobe_open_legacy(const char *probe_name, bool retprobe,
                                         const char *binary_path, size_t offset, int pid)
 {
+       const size_t attr_sz = sizeof(struct perf_event_attr);
        struct perf_event_attr attr;
        int type, pfd, err;
 
@@ -10458,8 +10466,8 @@ static int perf_event_uprobe_open_legacy(const char *probe_name, bool retprobe,
                goto err_clean_legacy;
        }
 
-       memset(&attr, 0, sizeof(attr));
-       attr.size = sizeof(attr);
+       memset(&attr, 0, attr_sz);
+       attr.size = attr_sz;
        attr.config = type;
        attr.type = PERF_TYPE_TRACEPOINT;
 
@@ -10998,7 +11006,8 @@ static int determine_tracepoint_id(const char *tp_category,
 static int perf_event_open_tracepoint(const char *tp_category,
                                      const char *tp_name)
 {
-       struct perf_event_attr attr = {};
+       const size_t attr_sz = sizeof(struct perf_event_attr);
+       struct perf_event_attr attr;
        char errmsg[STRERR_BUFSIZE];
        int tp_id, pfd, err;
 
@@ -11010,8 +11019,9 @@ static int perf_event_open_tracepoint(const char *tp_category,
                return tp_id;
        }
 
+       memset(&attr, 0, attr_sz);
        attr.type = PERF_TYPE_TRACEPOINT;
-       attr.size = sizeof(attr);
+       attr.size = attr_sz;
        attr.config = tp_id;
 
        pfd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, 0 /* cpu */,
@@ -11631,12 +11641,15 @@ struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
                                     void *ctx,
                                     const struct perf_buffer_opts *opts)
 {
+       const size_t attr_sz = sizeof(struct perf_event_attr);
        struct perf_buffer_params p = {};
-       struct perf_event_attr attr = {};
+       struct perf_event_attr attr;
 
        if (!OPTS_VALID(opts, perf_buffer_opts))
                return libbpf_err_ptr(-EINVAL);
 
+       memset(&attr, 0, attr_sz);
+       attr.size = attr_sz;
        attr.config = PERF_COUNT_SW_BPF_OUTPUT;
        attr.type = PERF_TYPE_SOFTWARE;
        attr.sample_type = PERF_SAMPLE_RAW;

diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c
index 6c01316..3510458 100644 (file)
--- a/tools/lib/bpf/netlink.c
+++ b/tools/lib/bpf/netlink.c
@@ -587,11 +587,12 @@ static int get_tc_info(struct nlmsghdr *nh, libbpf_dump_nlmsg_t fn,
 
 static int tc_add_fd_and_name(struct libbpf_nla_req *req, int fd)
 {
-       struct bpf_prog_info info = {};
+       struct bpf_prog_info info;
        __u32 info_len = sizeof(info);
        char name[256];
        int len, ret;
 
+       memset(&info, 0, info_len);
        ret = bpf_obj_get_info_by_fd(fd, &info, &info_len);
        if (ret < 0)
                return ret;

diff --git a/tools/lib/bpf/skel_internal.h b/tools/lib/bpf/skel_internal.h
index bd6f450..365d769 100644 (file)
--- a/tools/lib/bpf/skel_internal.h
+++ b/tools/lib/bpf/skel_internal.h
@@ -285,6 +285,8 @@ static inline int skel_link_create(int prog_fd, int target_fd,
 
 static inline int bpf_load_and_run(struct bpf_load_and_run_opts *opts)
 {
+       const size_t prog_load_attr_sz = offsetofend(union bpf_attr, fd_array);
+       const size_t test_run_attr_sz = offsetofend(union bpf_attr, test);
        int map_fd = -1, prog_fd = -1, key = 0, err;
        union bpf_attr attr;
 
@@ -302,7 +304,7 @@ static inline int bpf_load_and_run(struct bpf_load_and_run_opts *opts)
                goto out;
        }
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, prog_load_attr_sz);
        attr.prog_type = BPF_PROG_TYPE_SYSCALL;
        attr.insns = (long) opts->insns;
        attr.insn_cnt = opts->insns_sz / sizeof(struct bpf_insn);
@@ -313,18 +315,18 @@ static inline int bpf_load_and_run(struct bpf_load_and_run_opts *opts)
        attr.log_size = opts->ctx->log_size;
        attr.log_buf = opts->ctx->log_buf;
        attr.prog_flags = BPF_F_SLEEPABLE;
-       err = prog_fd = skel_sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
+       err = prog_fd = skel_sys_bpf(BPF_PROG_LOAD, &attr, prog_load_attr_sz);
        if (prog_fd < 0) {
                opts->errstr = "failed to load loader prog";
                set_err;
                goto out;
        }
 
-       memset(&attr, 0, sizeof(attr));
+       memset(&attr, 0, test_run_attr_sz);
        attr.test.prog_fd = prog_fd;
        attr.test.ctx_in = (long) opts->ctx;
        attr.test.ctx_size_in = opts->ctx->sz;
-       err = skel_sys_bpf(BPF_PROG_RUN, &attr, sizeof(attr));
+       err = skel_sys_bpf(BPF_PROG_RUN, &attr, test_run_attr_sz);
        if (err < 0 || (int)attr.test.retval < 0) {
                opts->errstr = "failed to execute loader prog";
                if (err < 0) {