From d777b2ddbecf509bc61ee4f0fe0d3b5a909d698a Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Tue, 25 Jul 2017 15:16:12 -0700 Subject: [PATCH] bpf: don't zero out the info struct in bpf_obj_get_info_by_fd() The buffer passed to bpf_obj_get_info_by_fd() should be initialized to zeros. Kernel will enforce that to guarantee we can safely extend info structures in the future. Making the bpf_obj_get_info_by_fd() call in libbpf perform the zeroing is problematic, however, since some members of the info structures may need to be initialized by the callers (for instance pointers to buffers to which kernel is to dump translated and jited images). Remove the zeroing and fix up the in-tree callers before any kernel has been released with this code. As Daniel points out this seems to be the intended operation anyway, since commit 95b9afd3987f ("bpf: Test for bpf ID") is itself setting the buffer pointers before calling bpf_obj_get_info_by_fd(). Signed-off-by: Jakub Kicinski Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- tools/lib/bpf/bpf.c | 1 - tools/testing/selftests/bpf/test_progs.c | 8 ++++++-- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 412a7c82995a..256f571f2ab5 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -314,7 +314,6 @@ int bpf_obj_get_info_by_fd(int prog_fd, void *info, __u32 *info_len) int err; bzero(&attr, sizeof(attr)); - bzero(info, *info_len); attr.info.bpf_fd = prog_fd; attr.info.info_len = *info_len; attr.info.info = ptr_to_u64(info); diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c index 5855cd3d3d45..1f7dd35551b9 100644 --- a/tools/testing/selftests/bpf/test_progs.c +++ b/tools/testing/selftests/bpf/test_progs.c @@ -340,6 +340,7 @@ static void test_bpf_obj_id(void) /* Check getting prog info */ info_len = sizeof(struct bpf_prog_info) * 2; + bzero(&prog_infos[i], info_len); prog_infos[i].jited_prog_insns = ptr_to_u64(jited_insns); prog_infos[i].jited_prog_len = sizeof(jited_insns); prog_infos[i].xlated_prog_insns = ptr_to_u64(xlated_insns); @@ -369,6 +370,7 @@ static void test_bpf_obj_id(void) /* Check getting map info */ info_len = sizeof(struct bpf_map_info) * 2; + bzero(&map_infos[i], info_len); err = bpf_obj_get_info_by_fd(map_fds[i], &map_infos[i], &info_len); if (CHECK(err || @@ -394,7 +396,7 @@ static void test_bpf_obj_id(void) nr_id_found = 0; next_id = 0; while (!bpf_prog_get_next_id(next_id, &next_id)) { - struct bpf_prog_info prog_info; + struct bpf_prog_info prog_info = {}; int prog_fd; info_len = sizeof(prog_info); @@ -418,6 +420,8 @@ static void test_bpf_obj_id(void) nr_id_found++; err = bpf_obj_get_info_by_fd(prog_fd, &prog_info, &info_len); + prog_infos[i].jited_prog_insns = 0; + prog_infos[i].xlated_prog_insns = 0; CHECK(err || info_len != sizeof(struct bpf_prog_info) || memcmp(&prog_info, &prog_infos[i], info_len), "get-prog-info(next_id->fd)", @@ -436,7 +440,7 @@ static void test_bpf_obj_id(void) nr_id_found = 0; next_id = 0; while (!bpf_map_get_next_id(next_id, &next_id)) { - struct bpf_map_info map_info; + struct bpf_map_info map_info = {}; int map_fd; info_len = sizeof(map_info); -- 2.20.1