diff options
Diffstat (limited to 'slirp/bootp.c')
| -rw-r--r-- | slirp/bootp.c | 32 |
1 files changed, 22 insertions, 10 deletions
diff --git a/slirp/bootp.c b/slirp/bootp.c index 9e7b53b..1e8185f 100644 --- a/slirp/bootp.c +++ b/slirp/bootp.c @@ -159,6 +159,7 @@ static void bootp_reply(Slirp *slirp, const struct bootp_t *bp) struct in_addr preq_addr; int dhcp_msg_type, val; uint8_t *q; + uint8_t *end; uint8_t client_ethaddr[ETH_ALEN]; /* extract exact DHCP msg type */ @@ -240,6 +241,7 @@ static void bootp_reply(Slirp *slirp, const struct bootp_t *bp) rbp->bp_siaddr = saddr.sin_addr; /* Server IP address */ q = rbp->bp_vend; + end = (uint8_t *)&rbp[1]; memcpy(q, rfc1533_cookie, 4); q += 4; @@ -292,24 +294,33 @@ static void bootp_reply(Slirp *slirp, const struct bootp_t *bp) if (*slirp->client_hostname) { val = strlen(slirp->client_hostname); - *q++ = RFC1533_HOSTNAME; - *q++ = val; - memcpy(q, slirp->client_hostname, val); - q += val; + if (q + val + 2 >= end) { + g_warning("DHCP packet size exceeded, " + "omitting host name option."); + } else { + *q++ = RFC1533_HOSTNAME; + *q++ = val; + memcpy(q, slirp->client_hostname, val); + q += val; + } } if (slirp->vdomainname) { val = strlen(slirp->vdomainname); - *q++ = RFC1533_DOMAINNAME; - *q++ = val; - memcpy(q, slirp->vdomainname, val); - q += val; + if (q + val + 2 >= end) { + g_warning("DHCP packet size exceeded, " + "omitting domain name option."); + } else { + *q++ = RFC1533_DOMAINNAME; + *q++ = val; + memcpy(q, slirp->vdomainname, val); + q += val; + } } if (slirp->vdnssearch) { - size_t spaceleft = sizeof(rbp->bp_vend) - (q - rbp->bp_vend); val = slirp->vdnssearch_len; - if (val + 1 > spaceleft) { + if (q + val >= end) { g_warning("DHCP packet size exceeded, " "omitting domain-search option."); } else { @@ -331,6 +342,7 @@ static void bootp_reply(Slirp *slirp, const struct bootp_t *bp) memcpy(q, nak_msg, sizeof(nak_msg) - 1); q += sizeof(nak_msg) - 1; } + assert(q < end); *q = RFC1533_END; daddr.sin_addr.s_addr = 0xffffffffu; |