emo/busybox
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

udhcpc: ignore zero-length DHCP options, take 2

Browse Source 
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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
networking/udhcp/common.c
View File

@ -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). * (this violates RFC 2132 section 3.14).
*/ */
if (len == 0) { if (len == 0) {
scan_state->rem -= OPT_LEN; scan_state->rem -= 2;
scan_state->optionptr += OPT_LEN; scan_state->optionptr += 2;
continue; continue;
} }
len += OPT_LEN; len += 2;
scan_state->rem -= len; scan_state->rem -= len;
if (scan_state->rem < 0) /* option is longer than options field? */ if (scan_state->rem < 0) /* option is longer than options field? */
goto complain; /* yes, complain and return NULL */ goto complain; /* yes, complain and return NULL */