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Commit 8c79b356 authored by Jakub Kicinski's avatar Jakub Kicinski Committed by Daniel Borkmann
Browse files

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: 99a44bef ("tools: bpftool: add owner_prog_type and owner_jited to bpftool output")
Signed-off-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: default avatarQuentin Monnet <quentin.monnet@netronome.com>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent c9e45767

tools/bpf/bpftool/common.c

+1 −5
Original line number Diff line number Diff line
@@ -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;

tools/bpf/bpftool/map.c

+8 −9
Original line number Diff line number Diff line
@@ -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);
@@ -569,6 +568,7 @@ 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");



		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);