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Netlink: attribute validation before parsing
Wanted netlink attributes are defined in a table, specifying their size and neediness. Removing the long conditions that did the validation before. Also parsing IPv4 and IPv6 versions regardless on the IPV6 macro.
This commit is contained in:
Jan Moskyto Matejka
Ondrej Zajicek (work)
parent
e422ca0f29
commit
ad27615760
@ -226,23 +226,97 @@ nl_checkin(struct nlmsghdr *h, int lsize)
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return NLMSG_DATA(h);
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}
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struct nl_want_attrs {
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u8 defined:1;
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u8 checksize:1;
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u8 size;
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};
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#define BIRD_IFLA_MAX (IFLA_WIRELESS+1)
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static struct nl_want_attrs ifla_attr_want[BIRD_IFLA_MAX] = {
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[IFLA_IFNAME] = { 1, 0, 0 },
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[IFLA_MTU] = { 1, 1, sizeof(u32) },
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[IFLA_WIRELESS] = { 1, 0, 0 },
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};
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#define BIRD_IFA_MAX (IFA_ANYCAST+1)
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#ifndef IPV6
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static struct nl_want_attrs ifa_attr_want4[BIRD_IFA_MAX] = {
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[IFA_ADDRESS] = { 1, 1, sizeof(ip4_addr) },
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[IFA_LOCAL] = { 1, 1, sizeof(ip4_addr) },
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[IFA_BROADCAST] = { 1, 1, sizeof(ip4_addr) },
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};
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#else
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static struct nl_want_attrs ifa_attr_want6[BIRD_IFA_MAX] = {
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[IFA_ADDRESS] = { 1, 1, sizeof(ip6_addr) },
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[IFA_LOCAL] = { 1, 1, sizeof(ip6_addr) },
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};
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#endif
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#define BIRD_RTA_MAX (RTA_TABLE+1)
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static struct nl_want_attrs mpnh_attr_want4[BIRD_RTA_MAX] = {
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[RTA_GATEWAY] = { 1, 1, sizeof(ip4_addr) },
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};
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#ifndef IPV6
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static struct nl_want_attrs rtm_attr_want4[BIRD_RTA_MAX] = {
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[RTA_DST] = { 1, 1, sizeof(ip4_addr) },
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[RTA_OIF] = { 1, 1, sizeof(u32) },
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[RTA_GATEWAY] = { 1, 1, sizeof(ip4_addr) },
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[RTA_PRIORITY] = { 1, 1, sizeof(u32) },
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[RTA_PREFSRC] = { 1, 1, sizeof(ip4_addr) },
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[RTA_METRICS] = { 1, 0, 0 },
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[RTA_MULTIPATH] = { 1, 0, 0 },
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[RTA_FLOW] = { 1, 1, sizeof(u32) },
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[RTA_TABLE] = { 1, 1, sizeof(u32) },
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};
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#else
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static struct nl_want_attrs rtm_attr_want6[BIRD_RTA_MAX] = {
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[RTA_DST] = { 1, 1, sizeof(ip6_addr) },
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[RTA_IIF] = { 1, 1, sizeof(u32) },
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[RTA_OIF] = { 1, 1, sizeof(u32) },
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[RTA_GATEWAY] = { 1, 1, sizeof(ip6_addr) },
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[RTA_PRIORITY] = { 1, 1, sizeof(u32) },
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[RTA_PREFSRC] = { 1, 1, sizeof(ip6_addr) },
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[RTA_METRICS] = { 1, 0, 0 },
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[RTA_FLOW] = { 1, 1, sizeof(u32) },
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[RTA_TABLE] = { 1, 1, sizeof(u32) },
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};
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#endif
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static int
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nl_parse_attrs(struct rtattr *a, struct rtattr **k, int ksize)
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nl_parse_attrs(struct rtattr *a, struct nl_want_attrs *want, struct rtattr **k, int ksize)
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{
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int max = ksize / sizeof(struct rtattr *);
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bzero(k, ksize);
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while (RTA_OK(a, nl_attr_len))
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for ( ; RTA_OK(a, nl_attr_len); a = RTA_NEXT(a, nl_attr_len))
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{
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if (a->rta_type < max)
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k[a->rta_type] = a;
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a = RTA_NEXT(a, nl_attr_len);
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if ((a->rta_type >= max) || !want[a->rta_type].defined)
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continue;
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if (want[a->rta_type].checksize && (RTA_PAYLOAD(a) != want[a->rta_type].size))
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{
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log(L_ERR "nl_parse_attrs: Malformed message received");
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return 0;
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}
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k[a->rta_type] = a;
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}
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if (nl_attr_len)
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{
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log(L_ERR "nl_parse_attrs: remnant of size %d", nl_attr_len);
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return 0;
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}
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else
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return 1;
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}
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@ -350,7 +424,7 @@ nl_parse_multipath(struct krt_proto *p, struct rtattr *ra)
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static int nh_buf_size; /* in number of structures */
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static int nh_buf_used;
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struct rtattr *a[RTA_CACHEINFO+1];
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struct rtattr *a[BIRD_RTA_MAX];
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struct rtnexthop *nh = RTA_DATA(ra);
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struct mpnh *rv, *first, **last;
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int len = RTA_PAYLOAD(ra);
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@ -381,12 +455,9 @@ nl_parse_multipath(struct krt_proto *p, struct rtattr *ra)
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/* Nonexistent RTNH_PAYLOAD ?? */
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nl_attr_len = nh->rtnh_len - RTNH_LENGTH(0);
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nl_parse_attrs(RTNH_DATA(nh), a, sizeof(a));
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nl_parse_attrs(RTNH_DATA(nh), mpnh_attr_want4, a, sizeof(a));
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if (a[RTA_GATEWAY])
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{
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if (RTA_PAYLOAD(a[RTA_GATEWAY]) != sizeof(ip_addr))
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return NULL;
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memcpy(&rv->gw, RTA_DATA(a[RTA_GATEWAY]), sizeof(ip_addr));
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ipa_ntoh(rv->gw);
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@ -455,7 +526,7 @@ static void
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nl_parse_link(struct nlmsghdr *h, int scan)
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{
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struct ifinfomsg *i;
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struct rtattr *a[IFLA_WIRELESS+1];
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struct rtattr *a[BIRD_IFLA_MAX];
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int new = h->nlmsg_type == RTM_NEWLINK;
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struct iface f = {};
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struct iface *ifi;
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@ -463,15 +534,23 @@ nl_parse_link(struct nlmsghdr *h, int scan)
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u32 mtu;
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uint fl;
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if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(IFLA_RTA(i), a, sizeof(a)))
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if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(IFLA_RTA(i), ifla_attr_want, a, sizeof(a)))
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return;
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if (!a[IFLA_IFNAME] || RTA_PAYLOAD(a[IFLA_IFNAME]) < 2 ||
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!a[IFLA_MTU] || RTA_PAYLOAD(a[IFLA_MTU]) != 4)
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if (!a[IFLA_IFNAME] || (RTA_PAYLOAD(a[IFLA_IFNAME]) < 2) || !a[IFLA_MTU])
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{
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if (scan || !a[IFLA_WIRELESS])
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log(L_ERR "nl_parse_link: Malformed message received");
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/*
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* IFLA_IFNAME and IFLA_MTU are required, in fact, but there may also come
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* a message with IFLA_WIRELESS set, where (e.g.) no IFLA_IFNAME exists.
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* We simply ignore all such messages with IFLA_WIRELESS without notice.
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*/
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if (a[IFLA_WIRELESS])
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return;
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log(L_ERR "KIF: Malformed message received");
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return;
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}
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name = RTA_DATA(a[IFLA_IFNAME]);
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mtu = rta_get_u32(a[IFLA_MTU]);
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@ -522,26 +601,40 @@ static void
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nl_parse_addr(struct nlmsghdr *h, int scan)
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{
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struct ifaddrmsg *i;
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struct rtattr *a[IFA_ANYCAST+1];
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struct rtattr *a[BIRD_IFA_MAX];
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int new = h->nlmsg_type == RTM_NEWADDR;
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struct ifa ifa;
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struct iface *ifi;
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int scope;
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if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(IFA_RTA(i), a, sizeof(a)))
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if (!(i = nl_checkin(h, sizeof(*i))))
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return;
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if (i->ifa_family != BIRD_AF)
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return;
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if (!a[IFA_ADDRESS] || RTA_PAYLOAD(a[IFA_ADDRESS]) != sizeof(ip_addr)
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#ifdef IPV6
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|| a[IFA_LOCAL] && RTA_PAYLOAD(a[IFA_LOCAL]) != sizeof(ip_addr)
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#else
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|| !a[IFA_LOCAL] || RTA_PAYLOAD(a[IFA_LOCAL]) != sizeof(ip_addr)
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|| (a[IFA_BROADCAST] && RTA_PAYLOAD(a[IFA_BROADCAST]) != sizeof(ip_addr))
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#endif
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)
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switch (i->ifa_family)
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{
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log(L_ERR "nl_parse_addr: Malformed message received");
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#ifndef IPV6
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case AF_INET:
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if (!nl_parse_attrs(IFA_RTA(i), ifa_attr_want4, a, sizeof(a)))
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return;
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if (!a[IFA_LOCAL])
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{
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log(L_ERR "KIF: Malformed message received (missing IFA_LOCAL)");
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return;
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}
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break;
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#else
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case AF_INET6:
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if (!nl_parse_attrs(IFA_RTA(i), ifa_attr_want6, a, sizeof(a)))
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return;
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break;
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#endif
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default:
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return;
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}
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if (!a[IFA_ADDRESS])
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{
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log(L_ERR "KIF: Malformed message received (missing IFA_ADDRESS)");
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return;
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}
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@ -835,7 +928,7 @@ nl_parse_route(struct nlmsghdr *h, int scan)
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{
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struct krt_proto *p;
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struct rtmsg *i;
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struct rtattr *a[RTA_TABLE+1];
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struct rtattr *a[BIRD_RTA_MAX];
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int new = h->nlmsg_type == RTM_NEWROUTE;
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ip_addr dst = IPA_NONE;
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@ -843,25 +936,27 @@ nl_parse_route(struct nlmsghdr *h, int scan)
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u32 table;
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int src;
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if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(RTM_RTA(i), a, sizeof(a)))
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if (!(i = nl_checkin(h, sizeof(*i))))
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return;
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if (i->rtm_family != BIRD_AF)
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return;
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if ((a[RTA_DST] && RTA_PAYLOAD(a[RTA_DST]) != sizeof(ip_addr)) ||
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#ifdef IPV6
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(a[RTA_IIF] && RTA_PAYLOAD(a[RTA_IIF]) != 4) ||
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#endif
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(a[RTA_OIF] && RTA_PAYLOAD(a[RTA_OIF]) != 4) ||
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(a[RTA_TABLE] && RTA_PAYLOAD(a[RTA_TABLE]) != 4) ||
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(a[RTA_GATEWAY] && RTA_PAYLOAD(a[RTA_GATEWAY]) != sizeof(ip_addr)) ||
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(a[RTA_PRIORITY] && RTA_PAYLOAD(a[RTA_PRIORITY]) != 4) ||
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(a[RTA_PREFSRC] && RTA_PAYLOAD(a[RTA_PREFSRC]) != sizeof(ip_addr)) ||
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(a[RTA_FLOW] && RTA_PAYLOAD(a[RTA_FLOW]) != 4))
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switch (i->rtm_family)
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{
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log(L_ERR "KRT: Malformed message received");
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#ifndef IPV6
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case AF_INET:
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if (!nl_parse_attrs(RTM_RTA(i), rtm_attr_want4, a, sizeof(a)))
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return;
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break;
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#else
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case AF_INET6:
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if (!nl_parse_attrs(RTM_RTA(i), rtm_attr_want6, a, sizeof(a)))
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return;
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break;
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#endif
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default:
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return;
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}
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if (a[RTA_DST])
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{
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memcpy(&dst, RTA_DATA(a[RTA_DST]), sizeof(dst));
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@ -938,7 +1033,7 @@ nl_parse_route(struct nlmsghdr *h, int scan)
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{
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case RTN_UNICAST:
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if (a[RTA_MULTIPATH])
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if (a[RTA_MULTIPATH] && (i->rtm_family == AF_INET))
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{
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ra.dest = RTD_MULTIPATH;
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ra.nexthops = nl_parse_multipath(p, a[RTA_MULTIPATH]);
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