| author | Brian Foley <bpfoley@google.com> | 2016-10-25 12:20:55 (GMT) |
|---|---|---|
| committer | Denys Vlasenko <vda.linux@googlemail.com> | 2016-10-25 12:20:55 (GMT) |
| commit | f9beeb22e2a4128ed85a8dc267d0823e5cfd3f47 (patch) | |
| tree | 6c83a9185531079940b7c5b0d687c253a4bced06 | |
| parent | 69312e87b008363575a6d6603f54f94d8150e1cc (diff) | |
| download | busybox-f9beeb22e2a4128ed85a8dc267d0823e5cfd3f47.zip busybox-f9beeb22e2a4128ed85a8dc267d0823e5cfd3f47.tar.gz busybox-f9beeb22e2a4128ed85a8dc267d0823e5cfd3f47.tar.bz2 | |
udhcpc: check read of option length byte to be within packet
function old new delta
udhcp_get_option 215 220 +5
udhcp_run_script 802 803 +1
Signed-off-by: Brian Foley <bpfoley@google.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
| -rw-r--r-- | networking/udhcp/common.c | 8 | ||||
| -rw-r--r-- | networking/udhcp/dhcpc.c | 4 |
2 files changed, 9 insertions, 3 deletions
diff --git a/networking/udhcp/common.c b/networking/udhcp/common.c index 0cf4dab..589bcd6 100644 --- a/networking/udhcp/common.c +++ b/networking/udhcp/common.c @@ -226,9 +226,12 @@ uint8_t* FAST_FUNC udhcp_get_option(struct dhcp_packet *packet, int code) rem = sizeof(packet->options); while (1) { if (rem <= 0) { + complain: bb_error_msg("bad packet, malformed option field"); return NULL; } + + /* DHCP_PADDING and DHCP_END have no [len] byte */ if (optionptr[OPT_CODE] == DHCP_PADDING) { rem--; optionptr++; @@ -251,10 +254,13 @@ uint8_t* FAST_FUNC udhcp_get_option(struct dhcp_packet *packet, int code) } break; } + + if (rem <= OPT_LEN) + goto complain; /* complain and return NULL */ len = 2 + optionptr[OPT_LEN]; rem -= len; if (rem < 0) - continue; /* complain and return NULL */ + goto complain; /* complain and return NULL */ if (optionptr[OPT_CODE] == code) { log_option("option found", optionptr); diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c index bef7327..1c10511 100644 --- a/networking/udhcp/dhcpc.c +++ b/networking/udhcp/dhcpc.c @@ -450,7 +450,7 @@ static char **fill_envp(struct dhcp_packet *packet) temp = udhcp_get_option(packet, i); if (temp) { if (i == DHCP_OPTION_OVERLOAD) - overload = *temp; + overload |= *temp; else if (i == DHCP_SUBNET) envc++; /* for $mask */ envc++; @@ -476,7 +476,7 @@ static char **fill_envp(struct dhcp_packet *packet) * uint16_t secs; // elapsed since client began acquisition/renewal * uint16_t flags; // only one flag so far: bcast. Never set by server * uint32_t ciaddr; // client IP (usually == yiaddr. can it be different - * // if during renew server wants to give us differn IP?) + * // if during renew server wants to give us different IP?) * uint32_t gateway_nip; // relay agent IP address * uint8_t chaddr[16]; // link-layer client hardware address (MAC) * TODO: export gateway_nip as $giaddr? |