On 11/07/13 17:32, Ted Unangst wrote:
> On Thu, Nov 07, 2013 at 17:19, Peter J. Philipp wrote:
>
>>> + gid = getgid();
>>> +
>>> + if (setgroups(1, &gid) == -1)
>>> + err(1, "setgroups");
>>> +
>>> + if (setresgid(gid, gid, gid) == -1)
>>> + err(1, "setresgid");
>>> +
>>> if (setresuid(uid, uid, uid) == -1)
>>> err(1, "setresuid");
>>>
>>
>>
>> I thought about it and thought my patch didn't really do anything. So
>
> Right. This doesn't do anything. traceroute isn't setgid, it has no
> group privileges to revoke.
>
>
>> /* DiffServ Codepoints and other TOS mappings */
>> + /* KEEP SORTED */
>> const struct toskeywords {
>> const char *keyword;
>> int val;
>> @@ -1258,14 +1268,13 @@ map_tos(char *s, int *val)
>> { NULL, -1 },
>> };
>>
>> - for (t = toskeywords; t->keyword != NULL; t++) {
>> - if (strcmp(s, t->keyword) == 0) {
>> - *val = t->val;
>> - return (1);
>> - }
>> - }
>> + t = bsearch(s, toskeywords, nitems(toskeywords), sizeof(struct
>> toskeywords), (int (*)(const void *, const void *))strcmp);
>
> I don't like the way this is abusing types. In fact, I don't think this
> even works. Did you test it? A pointer to a struct toskeyword will not
> have the same value as the keyword member.
>
>
OK I'll stop abusing. Here is my reasoning for the setgid change.
Pretend there is a way to break into the binary by means of the socket,
then I thought it'd be neat if it was disallowed to write into groups
that a user was in at the moment this binary was executed. I think this
is paranoid enough.
And yes I tested it. I used reliability keyword and throughput keyword
and a notused keyword, they matched in tcpdump with the #defined values
and bailed on the third keyword.
# traceroute -t throughput venus
traceroute to venus.centroid.eu (192.168.60.1), 64 hops max, 40 byte packets
1 uranus (192.168.34.1) 0.211 ms 0.188 ms 0.248 ms
# 17:10:48.701844 192.168.34.4.52757 > 192.168.60.1.33435: [no cksum]
udp 12 [tos 0x8] [ttl 1] (id 52758, len 40)
To be honest I'm not at a high level as you so I don't understand what
the last sentence means. I had the bsearch manpage to guide me and it
was surprising to me this even worked so well.
I'm gonna leave this the way it is now.
-peter
