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udhcpc: ignore zero-length DHCP options, take 2

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advance the optionptr by two bytes, not one

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2021-03-16 11:42:56 +01:00
parent 1c461df70a
commit fe78d70ec6
1 changed files with 3 additions and 3 deletions
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6
networking/udhcp/common.c
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@ -282,11 +282,11 @@ uint8_t* FAST_FUNC udhcp_scan_options(struct dhcp_packet *packet, struct dhcp_sc
* (this violates RFC 2132 section 3.14).
*/
if (len == 0) {
scan_state->rem -= OPT_LEN;
scan_state->optionptr += OPT_LEN;
scan_state->rem -= 2;
scan_state->optionptr += 2;
continue;
}
len += OPT_LEN;
len += 2;
scan_state->rem -= len;
if (scan_state->rem < 0) /* option is longer than options field? */
goto complain; /* yes, complain and return NULL */