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dhclient: Log a warning instead of bailing upon "illegal" options

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In Azure, the DHCP servers add private option (id 0xf5), which contains
binary form of an IPv4 address. Once this option is converted to string
form, it could contain '$', e.g.

IPv4 address: 100.72.36.54
binary form: 0x64 0x48 0x24 0x36
string form: "dH$6"

dhclient bails upon "illegal" options like the above example, thus the
VM bring-up will fail.

Also as a side note, this "illegal" option detection was added in
OpenBSD ~11years ago:
http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/sbin/dhclient/dhclient.c?rev=1.50&content-type=text/x-cvsweb-markup

And it was removed along with the removal of script support in OpenBSD
~3years ago:
http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/sbin/dhclient/dhclient.c?rev=1.159&content-type=text/x-cvsweb-markup

Reported by:	Hongxiong Xian <v-hoxian microsoft com>
Reviewed by:	jhb, Dexuan Cui <decui microsoft com>
Tested by:	Hongxiong Xian <v-hoxian microsoft com>
Analyzed by:	Dong Liu <doliu microsoft com>
MFC after:	1 week
Sponsored by:	Microsoft OSTC
Differential Revision:	https://reviews.freebsd.org/D5853
This commit is contained in:
Sepherosa Ziehau 2016-04-20 23:56:25 +00:00
parent 1782ba0c1f
commit dd09ce3930
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=298385
1 changed files with 11 additions and 10 deletions
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21
sbin/dhclient/dhclient.c
View file

@ -2275,6 +2275,17 @@ script_set_env(struct client_state *client, const char *prefix,
{
int i, j, namelen;
/* No `` or $() command substitution allowed in environment values! */
for (j=0; j < strlen(value); j++)
switch (value[j]) {
case '`':
case '$':
warning("illegal character (%c) in value '%s'",
value[j], value);
/* Ignore this option */
return;
}
namelen = strlen(name);
for (i = 0; client->scriptEnv[i]; i++)
@ -2311,16 +2322,6 @@ script_set_env(struct client_state *client, const char *prefix,
strlen(value) + 1);
if (client->scriptEnv[i] == NULL)
error("script_set_env: no memory for variable assignment");
/* No `` or $() command substitution allowed in environment values! */
for (j=0; j < strlen(value); j++)
switch (value[j]) {
case '`':
case '$':
error("illegal character (%c) in value '%s'", value[j],
value);
/* not reached */
}
snprintf(client->scriptEnv[i], strlen(prefix) + strlen(name) +
1 + strlen(value) + 1, "%s%s=%s", prefix, name, value);
}