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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: 99a44bef58 ("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>
This commit is contained in:
Jakub Kicinski 2019-01-28 10:01:21 -08:00 committed by Daniel Borkmann
parent c9e4576743
commit 8c79b35693
2 changed files with 9 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
tools/bpf/bpftool/common.c
View File

@ -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;

17
tools/bpf/bpftool/map.c
View File

@ -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);