diff options
Diffstat (limited to 'networking/udhcp/common.c')
| -rw-r--r-- | networking/udhcp/common.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/networking/udhcp/common.c b/networking/udhcp/common.c index e5fd74f..41b05b8 100644 --- a/networking/udhcp/common.c +++ b/networking/udhcp/common.c @@ -272,6 +272,15 @@ uint8_t* FAST_FUNC udhcp_get_option(struct dhcp_packet *packet, int code) goto complain; /* complain and return NULL */ if (optionptr[OPT_CODE] == code) { + if (optionptr[OPT_LEN] == 0) { + /* So far no valid option with length 0 known. + * Having this check means that searching + * for DHCP_MESSAGE_TYPE need not worry + * that returned pointer might be unsafe + * to dereference. + */ + goto complain; /* complain and return NULL */ + } log_option("option found", optionptr); return optionptr + OPT_DATA; } @@ -289,6 +298,16 @@ uint8_t* FAST_FUNC udhcp_get_option(struct dhcp_packet *packet, int code) return NULL; } +uint8_t* FAST_FUNC udhcp_get_option32(struct dhcp_packet *packet, int code) +{ + uint8_t *r = udhcp_get_option(packet, code); + if (r) { + if (r[-1] != 4) + r = NULL; + } + return r; +} + /* Return the position of the 'end' option (no bounds checking) */ int FAST_FUNC udhcp_end_option(uint8_t *optionptr) { |