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 <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 8 insertions, 9 deletions

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);