From 8c79b35693380d856dcbbc21629682a90f26ca62 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Mon, 28 Jan 2019 10:01:21 -0800 Subject: [PATCH] tools: bpftool: fix crash with un-owned prog arrays Prog arrays don't have 'owner_prog_type' and 'owner_jited' fields in their fdinfo when they are created. Those fields are set and reported when first program is checked for compatibility by bpf_prog_array_compatible(). This means that bpftool cannot expect the fields to always be there. Currently trying to show maps on a system with an un-owned prog array leads to a crash: $ bpftool map show 389: prog_array name tail_call_map flags 0x0 Error: key 'owner_prog_type' not found in fdinfo Error: key 'owner_jited' not found in fdinfo key 4B value 4B max_entries 4 memlock 4096B Segmentation fault (core dumped) We pass a NULL pointer to atoi(). Remove the assumption that fdinfo keys are always present. Add missing validations and remove the p_err() calls which may lead to broken JSON output as caller will not propagate the failure. Fixes: 99a44bef5870 ("tools: bpftool: add owner_prog_type and owner_jited to bpftool output") Signed-off-by: Jakub Kicinski Reviewed-by: Quentin Monnet Acked-by: Song Liu Signed-off-by: Daniel Borkmann --- tools/bpf/bpftool/common.c | 6 +----- tools/bpf/bpftool/map.c | 17 ++++++++--------- 2 files changed, 9 insertions(+), 14 deletions(-) diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c index 897483457bf0..f7261fad45c1 100644 --- a/tools/bpf/bpftool/common.c +++ b/tools/bpf/bpftool/common.c @@ -297,10 +297,8 @@ char *get_fdinfo(int fd, const char *key) snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", fd); fdi = fopen(path, "r"); - if (!fdi) { - p_err("can't open fdinfo: %s", strerror(errno)); + if (!fdi) return NULL; - } while ((n = getline(&line, &line_n, fdi)) > 0) { char *value; @@ -313,7 +311,6 @@ char *get_fdinfo(int fd, const char *key) value = strchr(line, '\t'); if (!value || !value[1]) { - p_err("malformed fdinfo!?"); free(line); return NULL; } @@ -326,7 +323,6 @@ char *get_fdinfo(int fd, const char *key) return line; } - p_err("key '%s' not found in fdinfo", key); free(line); fclose(fdi); return NULL; diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index 29a3468c6cf6..1ef1ee2280a2 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -513,10 +513,9 @@ static int show_map_close_json(int fd, struct bpf_map_info *info) jsonw_uint_field(json_wtr, "owner_prog_type", prog_type); } - if (atoi(owner_jited)) - jsonw_bool_field(json_wtr, "owner_jited", true); - else - jsonw_bool_field(json_wtr, "owner_jited", false); + if (owner_jited) + jsonw_bool_field(json_wtr, "owner_jited", + !!atoi(owner_jited)); free(owner_prog_type); free(owner_jited); @@ -569,7 +568,8 @@ static int show_map_close_plain(int fd, struct bpf_map_info *info) char *owner_prog_type = get_fdinfo(fd, "owner_prog_type"); char *owner_jited = get_fdinfo(fd, "owner_jited"); - printf("\n\t"); + if (owner_prog_type || owner_jited) + printf("\n\t"); if (owner_prog_type) { unsigned int prog_type = atoi(owner_prog_type); @@ -579,10 +579,9 @@ static int show_map_close_plain(int fd, struct bpf_map_info *info) else printf("owner_prog_type %d ", prog_type); } - if (atoi(owner_jited)) - printf("owner jited"); - else - printf("owner not jited"); + if (owner_jited) + printf("owner%s jited", + atoi(owner_jited) ? "" : " not"); free(owner_prog_type); free(owner_jited); -- 2.11.0