PKG_NAME:=dnsmasq
PKG_UPSTREAM_VERSION:=2.80
PKG_VERSION:=$(subst test,~~test,$(subst rc,~rc,$(PKG_UPSTREAM_VERSION)))
-PKG_RELEASE:=16.1
+PKG_RELEASE:=16.2
PKG_SOURCE:=$(PKG_NAME)-$(PKG_UPSTREAM_VERSION).tar.xz
PKG_SOURCE_URL:=http://thekelleys.org.uk/dnsmasq
--- /dev/null
+From 4e96a4be685c9e4445f6ee79ad0b36b9119b502a Mon Sep 17 00:00:00 2001
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Wed, 11 Nov 2020 23:25:04 +0000
+Subject: Fix remote buffer overflow CERT VU#434904
+
+The problem is in the sort_rrset() function and allows a remote
+attacker to overwrite memory. Any dnsmasq instance with DNSSEC
+enabled is vulnerable.
+---
+ CHANGELOG | 7 +-
+ src/dnssec.c | 273 ++++++++++++++++++++++++++++-----------------------
+ 2 files changed, 158 insertions(+), 122 deletions(-)
+
+--- a/CHANGELOG
++++ b/CHANGELOG
+@@ -1,3 +1,9 @@
++ Fix a remote buffer overflow problem in the DNSSEC code. Any
++ dnsmasq with DNSSEC compiled in and enabled is vulnerable to this,
++ referenced by CERT VU#434904.
++
++
++>>>>>>> Fix remote buffer overflow CERT VU#434904
+ version 2.81
+ Impove cache behaviour for TCP connections. For ease of
+ implementaion, dnsmasq has always forked a new process to handle
+--- a/src/dnssec.c
++++ b/src/dnssec.c
+@@ -222,138 +222,147 @@ static int check_date_range(u32 date_sta
+ && serial_compare_32(curtime, date_end) == SERIAL_LT;
+ }
+
+-/* Return bytes of canonicalised rdata, when the return value is zero, the remaining
+- data, pointed to by *p, should be used raw. */
+-static int get_rdata(struct dns_header *header, size_t plen, unsigned char *end, char *buff, int bufflen,
+- unsigned char **p, u16 **desc)
++/* Return bytes of canonicalised rrdata one by one.
++ Init state->ip with the RR, and state->end with the end of same.
++ Init state->op to NULL.
++ Init state->desc to RR descriptor.
++ Init state->buff with a MAXDNAME * 2 buffer.
++
++ After each call which returns 1, state->op points to the next byte of data.
++ On returning 0, the end has been reached.
++*/
++struct rdata_state {
++ u16 *desc;
++ size_t c;
++ unsigned char *end, *ip, *op;
++ char *buff;
++};
++
++static int get_rdata(struct dns_header *header, size_t plen, struct rdata_state *state)
+ {
+- int d = **desc;
++ int d;
+
+- /* No more data needs mangling */
+- if (d == (u16)-1)
++ if (state->op && state->c != 1)
+ {
+- /* If there's more data than we have space for, just return what fits,
+- we'll get called again for more chunks */
+- if (end - *p > bufflen)
+- {
+- memcpy(buff, *p, bufflen);
+- *p += bufflen;
+- return bufflen;
+- }
+-
+- return 0;
++ state->op++;
++ state->c--;
++ return 1;
+ }
+-
+- (*desc)++;
+-
+- if (d == 0 && extract_name(header, plen, p, buff, 1, 0))
+- /* domain-name, canonicalise */
+- return to_wire(buff);
+- else
+- {
+- /* plain data preceding a domain-name, don't run off the end of the data */
+- if ((end - *p) < d)
+- d = end - *p;
++
++ while (1)
++ {
++ d = *(state->desc);
+
+- if (d != 0)
++ if (d == (u16)-1)
+ {
+- memcpy(buff, *p, d);
+- *p += d;
++ /* all the bytes to the end. */
++ if ((state->c = state->end - state->ip) != 0)
++ {
++ state->op = state->ip;
++ state->ip = state->end;;
++ }
++ else
++ return 0;
++ }
++ else
++ {
++ state->desc++;
++
++ if (d == (u16)0)
++ {
++ /* domain-name, canonicalise */
++ int len;
++
++ if (!extract_name(header, plen, &state->ip, state->buff, 1, 0) ||
++ (len = to_wire(state->buff)) == 0)
++ continue;
++
++ state->c = len;
++ state->op = (unsigned char *)state->buff;
++ }
++ else
++ {
++ /* plain data preceding a domain-name, don't run off the end of the data */
++ if ((state->end - state->ip) < d)
++ d = state->end - state->ip;
++
++ if (d == 0)
++ continue;
++
++ state->op = state->ip;
++ state->c = d;
++ state->ip += d;
++ }
+ }
+
+- return d;
++ return 1;
+ }
+ }
+
+-/* Bubble sort the RRset into the canonical order.
+- Note that the byte-streams from two RRs may get unsynced: consider
+- RRs which have two domain-names at the start and then other data.
+- The domain-names may have different lengths in each RR, but sort equal
+-
+- ------------
+- |abcde|fghi|
+- ------------
+- |abcd|efghi|
+- ------------
+-
+- leaving the following bytes as deciding the order. Hence the nasty left1 and left2 variables.
+-*/
++/* Bubble sort the RRset into the canonical order. */
+
+ static int sort_rrset(struct dns_header *header, size_t plen, u16 *rr_desc, int rrsetidx,
+ unsigned char **rrset, char *buff1, char *buff2)
+ {
+- int swap, quit, i, j;
++ int swap, i, j;
+
+ do
+ {
+ for (swap = 0, i = 0; i < rrsetidx-1; i++)
+ {
+- int rdlen1, rdlen2, left1, left2, len1, len2, len, rc;
+- u16 *dp1, *dp2;
+- unsigned char *end1, *end2;
++ int rdlen1, rdlen2;
++ struct rdata_state state1, state2;
++
+ /* Note that these have been determined to be OK previously,
+ so we don't need to check for NULL return here. */
+- unsigned char *p1 = skip_name(rrset[i], header, plen, 10);
+- unsigned char *p2 = skip_name(rrset[i+1], header, plen, 10);
+-
+- p1 += 8; /* skip class, type, ttl */
+- GETSHORT(rdlen1, p1);
+- end1 = p1 + rdlen1;
+-
+- p2 += 8; /* skip class, type, ttl */
+- GETSHORT(rdlen2, p2);
+- end2 = p2 + rdlen2;
+-
+- dp1 = dp2 = rr_desc;
+-
+- for (quit = 0, left1 = 0, left2 = 0, len1 = 0, len2 = 0; !quit;)
++ state1.ip = skip_name(rrset[i], header, plen, 10);
++ state2.ip = skip_name(rrset[i+1], header, plen, 10);
++ state1.op = state2.op = NULL;
++ state1.buff = buff1;
++ state2.buff = buff2;
++ state1.desc = state2.desc = rr_desc;
++
++ state1.ip += 8; /* skip class, type, ttl */
++ GETSHORT(rdlen1, state1.ip);
++ if (!CHECK_LEN(header, state1.ip, plen, rdlen1))
++ return rrsetidx; /* short packet */
++ state1.end = state1.ip + rdlen1;
++
++ state2.ip += 8; /* skip class, type, ttl */
++ GETSHORT(rdlen2, state2.ip);
++ if (!CHECK_LEN(header, state2.ip, plen, rdlen2))
++ return rrsetidx; /* short packet */
++ state2.end = state2.ip + rdlen2;
++
++ while (1)
+ {
+- if (left1 != 0)
+- memmove(buff1, buff1 + len1 - left1, left1);
+-
+- if ((len1 = get_rdata(header, plen, end1, buff1 + left1, (MAXDNAME * 2) - left1, &p1, &dp1)) == 0)
+- {
+- quit = 1;
+- len1 = end1 - p1;
+- memcpy(buff1 + left1, p1, len1);
+- }
+- len1 += left1;
+-
+- if (left2 != 0)
+- memmove(buff2, buff2 + len2 - left2, left2);
+-
+- if ((len2 = get_rdata(header, plen, end2, buff2 + left2, (MAXDNAME *2) - left2, &p2, &dp2)) == 0)
+- {
+- quit = 1;
+- len2 = end2 - p2;
+- memcpy(buff2 + left2, p2, len2);
+- }
+- len2 += left2;
+-
+- if (len1 > len2)
+- left1 = len1 - len2, left2 = 0, len = len2;
+- else
+- left2 = len2 - len1, left1 = 0, len = len1;
++ int ok1, ok2;
+
+- rc = (len == 0) ? 0 : memcmp(buff1, buff2, len);
+-
+- if (rc > 0 || (rc == 0 && quit && len1 > len2))
+- {
+- unsigned char *tmp = rrset[i+1];
+- rrset[i+1] = rrset[i];
+- rrset[i] = tmp;
+- swap = quit = 1;
+- }
+- else if (rc == 0 && quit && len1 == len2)
++ ok1 = get_rdata(header, plen, &state1);
++ ok2 = get_rdata(header, plen, &state2);
++
++ if (!ok1 && !ok2)
+ {
+ /* Two RRs are equal, remove one copy. RFC 4034, para 6.3 */
+ for (j = i+1; j < rrsetidx-1; j++)
+ rrset[j] = rrset[j+1];
+ rrsetidx--;
+ i--;
++ break;
++ }
++ else if (ok1 && (!ok2 || *state1.op > *state2.op))
++ {
++ unsigned char *tmp = rrset[i+1];
++ rrset[i+1] = rrset[i];
++ rrset[i] = tmp;
++ swap = 1;
++ break;
+ }
+- else if (rc < 0)
+- quit = 1;
++ else if (ok2 && (!ok1 || *state2.op > *state1.op))
++ break;
++
++ /* arrive here when bytes are equal, go round the loop again
++ and compare the next ones. */
+ }
+ }
+ } while (swap);
+@@ -549,15 +558,18 @@ static int validate_rrset(time_t now, st
+ wire_len = to_wire(keyname);
+ hash->update(ctx, (unsigned int)wire_len, (unsigned char*)keyname);
+ from_wire(keyname);
++
++#define RRBUFLEN 300 /* Most RRs are smaller than this. */
+
+ for (i = 0; i < rrsetidx; ++i)
+ {
+- int seg;
+- unsigned char *end, *cp;
+- u16 len, *dp;
++ int j;
++ struct rdata_state state;
++ u16 len;
++ unsigned char rrbuf[RRBUFLEN];
+
+ p = rrset[i];
+-
++
+ if (!extract_name(header, plen, &p, name, 1, 10))
+ return STAT_BOGUS;
+
+@@ -566,12 +578,11 @@ static int validate_rrset(time_t now, st
+ /* if more labels than in RRsig name, hash *.<no labels in rrsig labels field> 4035 5.3.2 */
+ if (labels < name_labels)
+ {
+- int k;
+- for (k = name_labels - labels; k != 0; k--)
++ for (j = name_labels - labels; j != 0; j--)
+ {
+ while (*name_start != '.' && *name_start != 0)
+ name_start++;
+- if (k != 1 && *name_start == '.')
++ if (j != 1 && *name_start == '.')
+ name_start++;
+ }
+
+@@ -592,24 +603,44 @@ static int validate_rrset(time_t now, st
+ if (!CHECK_LEN(header, p, plen, rdlen))
+ return STAT_BOGUS;
+
+- end = p + rdlen;
+-
+- /* canonicalise rdata and calculate length of same, use name buffer as workspace.
+- Note that name buffer is twice MAXDNAME long in DNSSEC mode. */
+- cp = p;
+- dp = rr_desc;
+- for (len = 0; (seg = get_rdata(header, plen, end, name, MAXDNAME * 2, &cp, &dp)) != 0; len += seg);
+- len += end - cp;
+- len = htons(len);
++ /* canonicalise rdata and calculate length of same, use
++ name buffer as workspace for get_rdata. */
++ state.ip = p;
++ state.op = NULL;
++ state.desc = rr_desc;
++ state.buff = name;
++ state.end = p + rdlen;
++
++ for (j = 0; get_rdata(header, plen, &state); j++)
++ if (j < RRBUFLEN)
++ rrbuf[j] = *state.op;
++
++ len = htons((u16)j);
+ hash->update(ctx, 2, (unsigned char *)&len);
++
++ /* If the RR is shorter than RRBUFLEN (most of them, in practice)
++ then we can just digest it now. If it exceeds RRBUFLEN we have to
++ go back to the start and do it in chunks. */
++ if (j >= RRBUFLEN)
++ {
++ state.ip = p;
++ state.op = NULL;
++ state.desc = rr_desc;
++
++ for (j = 0; get_rdata(header, plen, &state); j++)
++ {
++ rrbuf[j] = *state.op;
++
++ if (j == RRBUFLEN - 1)
++ {
++ hash->update(ctx, RRBUFLEN, rrbuf);
++ j = -1;
++ }
++ }
++ }
+
+- /* Now canonicalise again and digest. */
+- cp = p;
+- dp = rr_desc;
+- while ((seg = get_rdata(header, plen, end, name, MAXDNAME * 2, &cp, &dp)))
+- hash->update(ctx, seg, (unsigned char *)name);
+- if (cp != end)
+- hash->update(ctx, end - cp, cp);
++ if (j != 0)
++ hash->update(ctx, j, rrbuf);
+ }
+
+ hash->digest(ctx, hash->digest_size, digest);
--- /dev/null
+From 257ac0c5f7732cbc6aa96fdd3b06602234593aca Mon Sep 17 00:00:00 2001
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Thu, 12 Nov 2020 18:49:23 +0000
+Subject: Check destination of DNS UDP query replies.
+
+At any time, dnsmasq will have a set of sockets open, bound to
+random ports, on which it sends queries to upstream nameservers.
+This patch fixes the existing problem that a reply for ANY in-flight
+query would be accepted via ANY open port, which increases the
+chances of an attacker flooding answers "in the blind" in an
+attempt to poison the DNS cache. CERT VU#434904 refers.
+---
+ CHANGELOG | 6 +++++-
+ src/forward.c | 37 ++++++++++++++++++++++++++++---------
+ 2 files changed, 33 insertions(+), 10 deletions(-)
+
+--- a/CHANGELOG
++++ b/CHANGELOG
+@@ -2,8 +2,12 @@
+ dnsmasq with DNSSEC compiled in and enabled is vulnerable to this,
+ referenced by CERT VU#434904.
+
++ Be sure to only accept UDP DNS query replies at the address
++ from which the query was originated. This keeps as much entropy
++ in the {query-ID, random-port} tuple as possible, help defeat
++ cache poisoning attacks. Refer: CERT VU#434904.
++
+
+->>>>>>> Fix remote buffer overflow CERT VU#434904
+ version 2.81
+ Impove cache behaviour for TCP connections. For ease of
+ implementaion, dnsmasq has always forked a new process to handle
+--- a/src/forward.c
++++ b/src/forward.c
+@@ -16,7 +16,7 @@
+
+ #include "dnsmasq.h"
+
+-static struct frec *lookup_frec(unsigned short id, void *hash);
++static struct frec *lookup_frec(unsigned short id, int fd, int family, void *hash);
+ static struct frec *lookup_frec_by_sender(unsigned short id,
+ union mysockaddr *addr,
+ void *hash);
+@@ -797,7 +797,7 @@ void reply_query(int fd, int family, tim
+ crc = questions_crc(header, n, daemon->namebuff);
+ #endif
+
+- if (!(forward = lookup_frec(ntohs(header->id), hash)))
++ if (!(forward = lookup_frec(ntohs(header->id), fd, family, hash)))
+ return;
+
+ #ifdef HAVE_DUMPFILE
+@@ -2289,14 +2289,25 @@ struct frec *get_new_frec(time_t now, in
+ }
+
+ /* crc is all-ones if not known. */
+-static struct frec *lookup_frec(unsigned short id, void *hash)
++static struct frec *lookup_frec(unsigned short id, int fd, int family, void *hash)
+ {
+ struct frec *f;
+
+ for(f = daemon->frec_list; f; f = f->next)
+ if (f->sentto && f->new_id == id &&
+ (!hash || memcmp(hash, f->hash, HASH_SIZE) == 0))
+- return f;
++ {
++ /* sent from random port */
++ if (family == AF_INET && f->rfd4 && f->rfd4->fd == fd)
++ return f;
++
++ if (family == AF_INET6 && f->rfd6 && f->rfd6->fd == fd)
++ return f;
++
++ /* sent to upstream from bound socket. */
++ if (f->sentto->sfd && f->sentto->sfd->fd == fd)
++ return f;
++ }
+
+ return NULL;
+ }
+@@ -2357,12 +2368,20 @@ void server_gone(struct server *server)
+ static unsigned short get_id(void)
+ {
+ unsigned short ret = 0;
++ struct frec *f;
+
+- do
+- ret = rand16();
+- while (lookup_frec(ret, NULL));
+-
+- return ret;
++ while (1)
++ {
++ ret = rand16();
++
++ /* ensure id is unique. */
++ for (f = daemon->frec_list; f; f = f->next)
++ if (f->sentto && f->new_id == ret)
++ break;
++
++ if (!f)
++ return ret;
++ }
+ }
+
+
--- /dev/null
+From 2d765867c597db18be9d876c9c17e2c0fe1953cd Mon Sep 17 00:00:00 2001
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Thu, 12 Nov 2020 22:06:07 +0000
+Subject: Use SHA-256 to provide security against DNS cache poisoning.
+
+Use the SHA-256 hash function to verify that DNS answers
+received are for the questions originally asked. This replaces
+the slightly insecure SHA-1 (when compiled with DNSSEC) or
+the very insecure CRC32 (otherwise). Refer: CERT VU#434904.
+---
+ CHANGELOG | 5 +
+ Makefile | 3 +-
+ bld/Android.mk | 2 +-
+ src/dnsmasq.h | 11 +-
+ src/dnssec.c | 31 -----
+ src/forward.c | 43 ++-----
+ src/hash_questions.c | 281 +++++++++++++++++++++++++++++++++++++++++++
+ src/rfc1035.c | 49 --------
+ 8 files changed, 301 insertions(+), 124 deletions(-)
+ create mode 100644 src/hash_questions.c
+
+--- a/CHANGELOG
++++ b/CHANGELOG
+@@ -7,6 +7,11 @@
+ in the {query-ID, random-port} tuple as possible, help defeat
+ cache poisoning attacks. Refer: CERT VU#434904.
+
++ Use the SHA-256 hash function to verify that DNS answers
++ received are for the questions originally asked. This replaces
++ the slightly insecure SHA-1 (when compiled with DNSSEC) or
++ the very insecure CRC32 (otherwise). Refer: CERT VU#434904.
++
+
+ version 2.81
+ Impove cache behaviour for TCP connections. For ease of
+--- a/Makefile
++++ b/Makefile
+@@ -77,7 +77,8 @@ objs = cache.o rfc1035.o util.o option.o
+ helper.o tftp.o log.o conntrack.o dhcp6.o rfc3315.o \
+ dhcp-common.o outpacket.o radv.o slaac.o auth.o ipset.o \
+ domain.o dnssec.o blockdata.o tables.o loop.o inotify.o \
+- poll.o rrfilter.o edns0.o arp.o crypto.o dump.o ubus.o metrics.o
++ poll.o rrfilter.o edns0.o arp.o crypto.o dump.o ubus.o \
++ metrics.o hash_questions.o
+
+ hdrs = dnsmasq.h config.h dhcp-protocol.h dhcp6-protocol.h \
+ dns-protocol.h radv-protocol.h ip6addr.h metrics.h
+--- a/bld/Android.mk
++++ b/bld/Android.mk
+@@ -11,7 +11,7 @@ LOCAL_SRC_FILES := bpf.c cache.c dbus.c
+ radv.c slaac.c auth.c ipset.c domain.c \
+ dnssec.c dnssec-openssl.c blockdata.c tables.c \
+ loop.c inotify.c poll.c rrfilter.c edns0.c arp.c \
+- crypto.c dump.c ubus.c
++ crypto.c dump.c ubus.c metrics.c hash_questions.c
+
+ LOCAL_MODULE := dnsmasq
+
+--- a/src/dnsmasq.h
++++ b/src/dnsmasq.h
+@@ -644,11 +644,7 @@ struct hostsfile {
+ #define FREC_TEST_PKTSZ 256
+ #define FREC_HAS_EXTRADATA 512
+
+-#ifdef HAVE_DNSSEC
+-#define HASH_SIZE 20 /* SHA-1 digest size */
+-#else
+-#define HASH_SIZE sizeof(int)
+-#endif
++#define HASH_SIZE 32 /* SHA-256 digest size */
+
+ struct frec {
+ union mysockaddr source;
+@@ -1199,7 +1195,6 @@ int check_for_bogus_wildcard(struct dns_
+ struct bogus_addr *baddr, time_t now);
+ int check_for_ignored_address(struct dns_header *header, size_t qlen, struct bogus_addr *baddr);
+ int check_for_local_domain(char *name, time_t now);
+-unsigned int questions_crc(struct dns_header *header, size_t plen, char *name);
+ size_t resize_packet(struct dns_header *header, size_t plen,
+ unsigned char *pheader, size_t hlen);
+ int add_resource_record(struct dns_header *header, char *limit, int *truncp,
+@@ -1227,9 +1222,11 @@ int dnssec_validate_reply(time_t now, st
+ int check_unsigned, int *neganswer, int *nons);
+ int dnskey_keytag(int alg, int flags, unsigned char *key, int keylen);
+ size_t filter_rrsigs(struct dns_header *header, size_t plen);
+-unsigned char* hash_questions(struct dns_header *header, size_t plen, char *name);
+ int setup_timestamp(void);
+
++/* hash_questions.c */
++unsigned char *hash_questions(struct dns_header *header, size_t plen, char *name);
++
+ /* crypto.c */
+ const struct nettle_hash *hash_find(char *name);
+ int hash_init(const struct nettle_hash *hash, void **ctxp, unsigned char **digestp);
+--- a/src/dnssec.c
++++ b/src/dnssec.c
+@@ -2082,35 +2082,4 @@ size_t dnssec_generate_query(struct dns_
+ return ret;
+ }
+
+-unsigned char* hash_questions(struct dns_header *header, size_t plen, char *name)
+-{
+- int q;
+- unsigned int len;
+- unsigned char *p = (unsigned char *)(header+1);
+- const struct nettle_hash *hash;
+- void *ctx;
+- unsigned char *digest;
+-
+- if (!(hash = hash_find("sha1")) || !hash_init(hash, &ctx, &digest))
+- return NULL;
+-
+- for (q = ntohs(header->qdcount); q != 0; q--)
+- {
+- if (!extract_name(header, plen, &p, name, 1, 4))
+- break; /* bad packet */
+-
+- len = to_wire(name);
+- hash->update(ctx, len, (unsigned char *)name);
+- /* CRC the class and type as well */
+- hash->update(ctx, 4, p);
+-
+- p += 4;
+- if (!CHECK_LEN(header, p, plen, 0))
+- break; /* bad packet */
+- }
+-
+- hash->digest(ctx, hash->digest_size, digest);
+- return digest;
+-}
+-
+ #endif /* HAVE_DNSSEC */
+--- a/src/forward.c
++++ b/src/forward.c
+@@ -248,19 +248,16 @@ static int forward_query(int udpfd, unio
+ union all_addr *addrp = NULL;
+ unsigned int flags = 0;
+ struct server *start = NULL;
+-#ifdef HAVE_DNSSEC
+ void *hash = hash_questions(header, plen, daemon->namebuff);
++#ifdef HAVE_DNSSEC
+ int do_dnssec = 0;
+-#else
+- unsigned int crc = questions_crc(header, plen, daemon->namebuff);
+- void *hash = &crc;
+ #endif
+ unsigned int gotname = extract_request(header, plen, daemon->namebuff, NULL);
+ unsigned char *oph = find_pseudoheader(header, plen, NULL, NULL, NULL, NULL);
+ (void)do_bit;
+
+ /* may be no servers available. */
+- if (forward || (hash && (forward = lookup_frec_by_sender(ntohs(header->id), udpaddr, hash))))
++ if (forward || (forward = lookup_frec_by_sender(ntohs(header->id), udpaddr, hash)))
+ {
+ /* If we didn't get an answer advertising a maximal packet in EDNS,
+ fall back to 1280, which should work everywhere on IPv6.
+@@ -761,9 +758,6 @@ void reply_query(int fd, int family, tim
+ size_t nn;
+ struct server *server;
+ void *hash;
+-#ifndef HAVE_DNSSEC
+- unsigned int crc;
+-#endif
+
+ /* packet buffer overwritten */
+ daemon->srv_save = NULL;
+@@ -790,12 +784,7 @@ void reply_query(int fd, int family, tim
+ if (difftime(now, server->pktsz_reduced) > UDP_TEST_TIME)
+ server->edns_pktsz = daemon->edns_pktsz;
+
+-#ifdef HAVE_DNSSEC
+ hash = hash_questions(header, n, daemon->namebuff);
+-#else
+- hash = &crc;
+- crc = questions_crc(header, n, daemon->namebuff);
+-#endif
+
+ if (!(forward = lookup_frec(ntohs(header->id), fd, family, hash)))
+ return;
+@@ -1100,8 +1089,7 @@ void reply_query(int fd, int family, tim
+ log_query(F_NOEXTRA | F_DNSSEC | F_IPV6, daemon->keyname, (union all_addr *)&(server->addr.in6.sin6_addr),
+ querystr("dnssec-query", querytype));
+
+- if ((hash = hash_questions(header, nn, daemon->namebuff)))
+- memcpy(new->hash, hash, HASH_SIZE);
++ memcpy(new->hash, hash_questions(header, nn, daemon->namebuff), HASH_SIZE);
+ new->new_id = get_id();
+ header->id = htons(new->new_id);
+ /* Save query for retransmission */
+@@ -1937,15 +1925,9 @@ unsigned char *tcp_request(int confd, ti
+ if (!flags && last_server)
+ {
+ struct server *firstsendto = NULL;
+-#ifdef HAVE_DNSSEC
+- unsigned char *newhash, hash[HASH_SIZE];
+- if ((newhash = hash_questions(header, (unsigned int)size, daemon->namebuff)))
+- memcpy(hash, newhash, HASH_SIZE);
+- else
+- memset(hash, 0, HASH_SIZE);
+-#else
+- unsigned int crc = questions_crc(header, (unsigned int)size, daemon->namebuff);
+-#endif
++ unsigned char hash[HASH_SIZE];
++ memcpy(hash, hash_questions(header, (unsigned int)size, daemon->namebuff), HASH_SIZE);
++
+ /* Loop round available servers until we succeed in connecting to one.
+ Note that this code subtly ensures that consecutive queries on this connection
+ which can go to the same server, do so. */
+@@ -2068,20 +2050,11 @@ unsigned char *tcp_request(int confd, ti
+ /* If the crc of the question section doesn't match the crc we sent, then
+ someone might be attempting to insert bogus values into the cache by
+ sending replies containing questions and bogus answers. */
+-#ifdef HAVE_DNSSEC
+- newhash = hash_questions(header, (unsigned int)m, daemon->namebuff);
+- if (!newhash || memcmp(hash, newhash, HASH_SIZE) != 0)
++ if (memcmp(hash, hash_questions(header, (unsigned int)m, daemon->namebuff), HASH_SIZE) != 0)
+ {
+ m = 0;
+ break;
+ }
+-#else
+- if (crc != questions_crc(header, (unsigned int)m, daemon->namebuff))
+- {
+- m = 0;
+- break;
+- }
+-#endif
+
+ m = process_reply(header, now, last_server, (unsigned int)m,
+ option_bool(OPT_NO_REBIND) && !norebind, no_cache_dnssec, cache_secure, bogusanswer,
+@@ -2295,7 +2268,7 @@ static struct frec *lookup_frec(unsigned
+
+ for(f = daemon->frec_list; f; f = f->next)
+ if (f->sentto && f->new_id == id &&
+- (!hash || memcmp(hash, f->hash, HASH_SIZE) == 0))
++ (memcmp(hash, f->hash, HASH_SIZE) == 0))
+ {
+ /* sent from random port */
+ if (family == AF_INET && f->rfd4 && f->rfd4->fd == fd)
+--- /dev/null
++++ b/src/hash_questions.c
+@@ -0,0 +1,281 @@
++/* Copyright (c) 2012-2020 Simon Kelley
++
++ This program is free software; you can redistribute it and/or modify
++ it under the terms of the GNU General Public License as published by
++ the Free Software Foundation; version 2 dated June, 1991, or
++ (at your option) version 3 dated 29 June, 2007.
++
++ This program is distributed in the hope that it will be useful,
++ but WITHOUT ANY WARRANTY; without even the implied warranty of
++ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
++ GNU General Public License for more details.
++
++ You should have received a copy of the GNU General Public License
++ along with this program. If not, see <http://www.gnu.org/licenses/>.
++*/
++
++
++/* Hash the question section. This is used to safely detect query
++ retransmission and to detect answers to questions we didn't ask, which
++ might be poisoning attacks. Note that we decode the name rather
++ than CRC the raw bytes, since replies might be compressed differently.
++ We ignore case in the names for the same reason.
++
++ The hash used is SHA-256. If we're building with DNSSEC support,
++ we use the Nettle cypto library. If not, we prefer not to
++ add a dependency on Nettle, and use a stand-alone implementaion.
++*/
++
++#include "dnsmasq.h"
++
++#ifdef HAVE_DNSSEC
++unsigned char *hash_questions(struct dns_header *header, size_t plen, char *name)
++{
++ int q;
++ unsigned char *p = (unsigned char *)(header+1);
++ const struct nettle_hash *hash;
++ void *ctx;
++ unsigned char *digest;
++
++ if (!(hash = hash_find("sha256")) || !hash_init(hash, &ctx, &digest))
++ {
++ /* don't think this can ever happen. */
++ static unsigned char dummy[HASH_SIZE];
++ static int warned = 0;
++
++ if (warned)
++ my_syslog(LOG_ERR, _("Failed to create SHA-256 hash object"));
++ warned = 1;
++
++ return dummy;
++ }
++
++ for (q = ntohs(header->qdcount); q != 0; q--)
++ {
++ char *cp, c;
++
++ if (!extract_name(header, plen, &p, name, 1, 4))
++ break; /* bad packet */
++
++ for (cp = name; (c = *cp); cp++)
++ if (c >= 'A' && c <= 'Z')
++ *cp += 'a' - 'A';
++
++ hash->update(ctx, cp - name, (unsigned char *)name);
++ /* CRC the class and type as well */
++ hash->update(ctx, 4, p);
++
++ p += 4;
++ if (!CHECK_LEN(header, p, plen, 0))
++ break; /* bad packet */
++ }
++
++ hash->digest(ctx, hash->digest_size, digest);
++ return digest;
++}
++
++#else /* HAVE_DNSSEC */
++
++#define SHA256_BLOCK_SIZE 32 // SHA256 outputs a 32 byte digest
++typedef unsigned char BYTE; // 8-bit byte
++typedef unsigned int WORD; // 32-bit word, change to "long" for 16-bit machines
++
++typedef struct {
++ BYTE data[64];
++ WORD datalen;
++ unsigned long long bitlen;
++ WORD state[8];
++} SHA256_CTX;
++
++static void sha256_init(SHA256_CTX *ctx);
++static void sha256_update(SHA256_CTX *ctx, const BYTE data[], size_t len);
++static void sha256_final(SHA256_CTX *ctx, BYTE hash[]);
++
++
++unsigned char *hash_questions(struct dns_header *header, size_t plen, char *name)
++{
++ int q;
++ unsigned char *p = (unsigned char *)(header+1);
++ SHA256_CTX ctx;
++ static BYTE digest[SHA256_BLOCK_SIZE];
++
++ sha256_init(&ctx);
++
++ for (q = ntohs(header->qdcount); q != 0; q--)
++ {
++ char *cp, c;
++
++ if (!extract_name(header, plen, &p, name, 1, 4))
++ break; /* bad packet */
++
++ for (cp = name; (c = *cp); cp++)
++ if (c >= 'A' && c <= 'Z')
++ *cp += 'a' - 'A';
++
++ sha256_update(&ctx, (BYTE *)name, cp - name);
++ /* CRC the class and type as well */
++ sha256_update(&ctx, (BYTE *)p, 4);
++
++ p += 4;
++ if (!CHECK_LEN(header, p, plen, 0))
++ break; /* bad packet */
++ }
++
++ sha256_final(&ctx, digest);
++ return (unsigned char *)digest;
++}
++
++/* Code from here onwards comes from https://github.com/B-Con/crypto-algorithms
++ and was written by Brad Conte (brad@bradconte.com), to whom all credit is given.
++
++ This code is in the public domain, and the copyright notice at the head of this
++ file does not apply to it.
++*/
++
++
++/****************************** MACROS ******************************/
++#define ROTLEFT(a,b) (((a) << (b)) | ((a) >> (32-(b))))
++#define ROTRIGHT(a,b) (((a) >> (b)) | ((a) << (32-(b))))
++
++#define CH(x,y,z) (((x) & (y)) ^ (~(x) & (z)))
++#define MAJ(x,y,z) (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)))
++#define EP0(x) (ROTRIGHT(x,2) ^ ROTRIGHT(x,13) ^ ROTRIGHT(x,22))
++#define EP1(x) (ROTRIGHT(x,6) ^ ROTRIGHT(x,11) ^ ROTRIGHT(x,25))
++#define SIG0(x) (ROTRIGHT(x,7) ^ ROTRIGHT(x,18) ^ ((x) >> 3))
++#define SIG1(x) (ROTRIGHT(x,17) ^ ROTRIGHT(x,19) ^ ((x) >> 10))
++
++/**************************** VARIABLES *****************************/
++static const WORD k[64] = {
++ 0x428a2f98,0x71374491,0xb5c0fbcf,0xe9b5dba5,0x3956c25b,0x59f111f1,0x923f82a4,0xab1c5ed5,
++ 0xd807aa98,0x12835b01,0x243185be,0x550c7dc3,0x72be5d74,0x80deb1fe,0x9bdc06a7,0xc19bf174,
++ 0xe49b69c1,0xefbe4786,0x0fc19dc6,0x240ca1cc,0x2de92c6f,0x4a7484aa,0x5cb0a9dc,0x76f988da,
++ 0x983e5152,0xa831c66d,0xb00327c8,0xbf597fc7,0xc6e00bf3,0xd5a79147,0x06ca6351,0x14292967,
++ 0x27b70a85,0x2e1b2138,0x4d2c6dfc,0x53380d13,0x650a7354,0x766a0abb,0x81c2c92e,0x92722c85,
++ 0xa2bfe8a1,0xa81a664b,0xc24b8b70,0xc76c51a3,0xd192e819,0xd6990624,0xf40e3585,0x106aa070,
++ 0x19a4c116,0x1e376c08,0x2748774c,0x34b0bcb5,0x391c0cb3,0x4ed8aa4a,0x5b9cca4f,0x682e6ff3,
++ 0x748f82ee,0x78a5636f,0x84c87814,0x8cc70208,0x90befffa,0xa4506ceb,0xbef9a3f7,0xc67178f2
++};
++
++/*********************** FUNCTION DEFINITIONS ***********************/
++static void sha256_transform(SHA256_CTX *ctx, const BYTE data[])
++{
++ WORD a, b, c, d, e, f, g, h, i, j, t1, t2, m[64];
++
++ for (i = 0, j = 0; i < 16; ++i, j += 4)
++ m[i] = (data[j] << 24) | (data[j + 1] << 16) | (data[j + 2] << 8) | (data[j + 3]);
++ for ( ; i < 64; ++i)
++ m[i] = SIG1(m[i - 2]) + m[i - 7] + SIG0(m[i - 15]) + m[i - 16];
++
++ a = ctx->state[0];
++ b = ctx->state[1];
++ c = ctx->state[2];
++ d = ctx->state[3];
++ e = ctx->state[4];
++ f = ctx->state[5];
++ g = ctx->state[6];
++ h = ctx->state[7];
++
++ for (i = 0; i < 64; ++i)
++ {
++ t1 = h + EP1(e) + CH(e,f,g) + k[i] + m[i];
++ t2 = EP0(a) + MAJ(a,b,c);
++ h = g;
++ g = f;
++ f = e;
++ e = d + t1;
++ d = c;
++ c = b;
++ b = a;
++ a = t1 + t2;
++ }
++
++ ctx->state[0] += a;
++ ctx->state[1] += b;
++ ctx->state[2] += c;
++ ctx->state[3] += d;
++ ctx->state[4] += e;
++ ctx->state[5] += f;
++ ctx->state[6] += g;
++ ctx->state[7] += h;
++}
++
++static void sha256_init(SHA256_CTX *ctx)
++{
++ ctx->datalen = 0;
++ ctx->bitlen = 0;
++ ctx->state[0] = 0x6a09e667;
++ ctx->state[1] = 0xbb67ae85;
++ ctx->state[2] = 0x3c6ef372;
++ ctx->state[3] = 0xa54ff53a;
++ ctx->state[4] = 0x510e527f;
++ ctx->state[5] = 0x9b05688c;
++ ctx->state[6] = 0x1f83d9ab;
++ ctx->state[7] = 0x5be0cd19;
++}
++
++static void sha256_update(SHA256_CTX *ctx, const BYTE data[], size_t len)
++{
++ WORD i;
++
++ for (i = 0; i < len; ++i)
++ {
++ ctx->data[ctx->datalen] = data[i];
++ ctx->datalen++;
++ if (ctx->datalen == 64) {
++ sha256_transform(ctx, ctx->data);
++ ctx->bitlen += 512;
++ ctx->datalen = 0;
++ }
++ }
++}
++
++static void sha256_final(SHA256_CTX *ctx, BYTE hash[])
++{
++ WORD i;
++
++ i = ctx->datalen;
++
++ // Pad whatever data is left in the buffer.
++ if (ctx->datalen < 56)
++ {
++ ctx->data[i++] = 0x80;
++ while (i < 56)
++ ctx->data[i++] = 0x00;
++ }
++ else
++ {
++ ctx->data[i++] = 0x80;
++ while (i < 64)
++ ctx->data[i++] = 0x00;
++ sha256_transform(ctx, ctx->data);
++ memset(ctx->data, 0, 56);
++ }
++
++ // Append to the padding the total message's length in bits and transform.
++ ctx->bitlen += ctx->datalen * 8;
++ ctx->data[63] = ctx->bitlen;
++ ctx->data[62] = ctx->bitlen >> 8;
++ ctx->data[61] = ctx->bitlen >> 16;
++ ctx->data[60] = ctx->bitlen >> 24;
++ ctx->data[59] = ctx->bitlen >> 32;
++ ctx->data[58] = ctx->bitlen >> 40;
++ ctx->data[57] = ctx->bitlen >> 48;
++ ctx->data[56] = ctx->bitlen >> 56;
++ sha256_transform(ctx, ctx->data);
++
++ // Since this implementation uses little endian byte ordering and SHA uses big endian,
++ // reverse all the bytes when copying the final state to the output hash.
++ for (i = 0; i < 4; ++i)
++ {
++ hash[i] = (ctx->state[0] >> (24 - i * 8)) & 0x000000ff;
++ hash[i + 4] = (ctx->state[1] >> (24 - i * 8)) & 0x000000ff;
++ hash[i + 8] = (ctx->state[2] >> (24 - i * 8)) & 0x000000ff;
++ hash[i + 12] = (ctx->state[3] >> (24 - i * 8)) & 0x000000ff;
++ hash[i + 16] = (ctx->state[4] >> (24 - i * 8)) & 0x000000ff;
++ hash[i + 20] = (ctx->state[5] >> (24 - i * 8)) & 0x000000ff;
++ hash[i + 24] = (ctx->state[6] >> (24 - i * 8)) & 0x000000ff;
++ hash[i + 28] = (ctx->state[7] >> (24 - i * 8)) & 0x000000ff;
++ }
++}
++
++#endif
+--- a/src/rfc1035.c
++++ b/src/rfc1035.c
+@@ -333,55 +333,6 @@ unsigned char *skip_section(unsigned cha
+ return ansp;
+ }
+
+-/* CRC the question section. This is used to safely detect query
+- retransmission and to detect answers to questions we didn't ask, which
+- might be poisoning attacks. Note that we decode the name rather
+- than CRC the raw bytes, since replies might be compressed differently.
+- We ignore case in the names for the same reason. Return all-ones
+- if there is not question section. */
+-#ifndef HAVE_DNSSEC
+-unsigned int questions_crc(struct dns_header *header, size_t plen, char *name)
+-{
+- int q;
+- unsigned int crc = 0xffffffff;
+- unsigned char *p1, *p = (unsigned char *)(header+1);
+-
+- for (q = ntohs(header->qdcount); q != 0; q--)
+- {
+- if (!extract_name(header, plen, &p, name, 1, 4))
+- return crc; /* bad packet */
+-
+- for (p1 = (unsigned char *)name; *p1; p1++)
+- {
+- int i = 8;
+- char c = *p1;
+-
+- if (c >= 'A' && c <= 'Z')
+- c += 'a' - 'A';
+-
+- crc ^= c << 24;
+- while (i--)
+- crc = crc & 0x80000000 ? (crc << 1) ^ 0x04c11db7 : crc << 1;
+- }
+-
+- /* CRC the class and type as well */
+- for (p1 = p; p1 < p+4; p1++)
+- {
+- int i = 8;
+- crc ^= *p1 << 24;
+- while (i--)
+- crc = crc & 0x80000000 ? (crc << 1) ^ 0x04c11db7 : crc << 1;
+- }
+-
+- p += 4;
+- if (!CHECK_LEN(header, p, plen, 0))
+- return crc; /* bad packet */
+- }
+-
+- return crc;
+-}
+-#endif
+-
+ size_t resize_packet(struct dns_header *header, size_t plen, unsigned char *pheader, size_t hlen)
+ {
+ unsigned char *ansp = skip_questions(header, plen);
--- /dev/null
+From 059aded0700309308dafd9720b0313ce52f6e189 Mon Sep 17 00:00:00 2001
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Thu, 12 Nov 2020 23:09:15 +0000
+Subject: Optimse RR digest calculation in DNSSEC.
+
+If an RR is of a type which doesn't need canonicalisation,
+bypass the relatively slow canonicalisation code, and insert
+it direct into the digest.
+---
+ src/dnssec.c | 82 +++++++++++++++++++++++++++++++---------------------
+ 1 file changed, 49 insertions(+), 33 deletions(-)
+
+--- a/src/dnssec.c
++++ b/src/dnssec.c
+@@ -559,7 +559,7 @@ static int validate_rrset(time_t now, st
+ hash->update(ctx, (unsigned int)wire_len, (unsigned char*)keyname);
+ from_wire(keyname);
+
+-#define RRBUFLEN 300 /* Most RRs are smaller than this. */
++#define RRBUFLEN 128 /* Most RRs are smaller than this. */
+
+ for (i = 0; i < rrsetidx; ++i)
+ {
+@@ -597,50 +597,66 @@ static int validate_rrset(time_t now, st
+ hash->update(ctx, (unsigned int)wire_len, (unsigned char *)name_start);
+ hash->update(ctx, 4, p); /* class and type */
+ hash->update(ctx, 4, (unsigned char *)&nsigttl);
+-
+- p += 8; /* skip class, type, ttl */
++
++ p += 8; /* skip type, class, ttl */
+ GETSHORT(rdlen, p);
+ if (!CHECK_LEN(header, p, plen, rdlen))
+ return STAT_BOGUS;
+-
+- /* canonicalise rdata and calculate length of same, use
+- name buffer as workspace for get_rdata. */
+- state.ip = p;
+- state.op = NULL;
+- state.desc = rr_desc;
+- state.buff = name;
+- state.end = p + rdlen;
+-
+- for (j = 0; get_rdata(header, plen, &state); j++)
+- if (j < RRBUFLEN)
+- rrbuf[j] = *state.op;
+
+- len = htons((u16)j);
+- hash->update(ctx, 2, (unsigned char *)&len);
+-
+- /* If the RR is shorter than RRBUFLEN (most of them, in practice)
+- then we can just digest it now. If it exceeds RRBUFLEN we have to
+- go back to the start and do it in chunks. */
+- if (j >= RRBUFLEN)
++ /* Optimisation for RR types which need no cannonicalisation.
++ This includes DNSKEY DS NSEC and NSEC3, which are also long, so
++ it saves lots of calls to get_rdata, and avoids the pessimal
++ segmented insertion, even with a small rrbuf[].
++
++ If canonicalisation is not needed, a simple insertion into the hash works.
++ */
++ if (*rr_desc == (u16)-1)
++ {
++ len = htons(rdlen);
++ hash->update(ctx, 2, (unsigned char *)&len);
++ hash->update(ctx, rdlen, p);
++ }
++ else
+ {
++ /* canonicalise rdata and calculate length of same, use
++ name buffer as workspace for get_rdata. */
+ state.ip = p;
+ state.op = NULL;
+ state.desc = rr_desc;
+-
++ state.buff = name;
++ state.end = p + rdlen;
++
+ for (j = 0; get_rdata(header, plen, &state); j++)
++ if (j < RRBUFLEN)
++ rrbuf[j] = *state.op;
++
++ len = htons((u16)j);
++ hash->update(ctx, 2, (unsigned char *)&len);
++
++ /* If the RR is shorter than RRBUFLEN (most of them, in practice)
++ then we can just digest it now. If it exceeds RRBUFLEN we have to
++ go back to the start and do it in chunks. */
++ if (j >= RRBUFLEN)
+ {
+- rrbuf[j] = *state.op;
+-
+- if (j == RRBUFLEN - 1)
+- {
+- hash->update(ctx, RRBUFLEN, rrbuf);
+- j = -1;
+- }
++ state.ip = p;
++ state.op = NULL;
++ state.desc = rr_desc;
++
++ for (j = 0; get_rdata(header, plen, &state); j++)
++ {
++ rrbuf[j] = *state.op;
++
++ if (j == RRBUFLEN - 1)
++ {
++ hash->update(ctx, RRBUFLEN, rrbuf);
++ j = -1;
++ }
++ }
+ }
++
++ if (j != 0)
++ hash->update(ctx, j, rrbuf);
+ }
+-
+- if (j != 0)
+- hash->update(ctx, j, rrbuf);
+ }
+
+ hash->digest(ctx, hash->digest_size, digest);
--- /dev/null
+From 824461192ca5098043f9ca4ddeba7df1f65b30ba Mon Sep 17 00:00:00 2001
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Sun, 15 Nov 2020 22:13:25 +0000
+Subject: Add missing check for NULL return from allocate_rfd().
+
+---
+ src/forward.c | 18 ++++++++++--------
+ 1 file changed, 10 insertions(+), 8 deletions(-)
+
+--- a/src/forward.c
++++ b/src/forward.c
+@@ -815,7 +815,6 @@ void reply_query(int fd, int family, tim
+ int is_sign;
+
+ #ifdef HAVE_DNSSEC
+- /* For DNSSEC originated queries, just retry the query to the same server. */
+ if (forward->flags & (FREC_DNSKEY_QUERY | FREC_DS_QUERY))
+ {
+ struct server *start;
+@@ -841,6 +840,8 @@ void reply_query(int fd, int family, tim
+ }
+
+
++ fd = -1;
++
+ if (start->sfd)
+ fd = start->sfd->fd;
+ else
+@@ -848,19 +849,21 @@ void reply_query(int fd, int family, tim
+ if (start->addr.sa.sa_family == AF_INET6)
+ {
+ /* may have changed family */
+- if (!forward->rfd6)
+- forward->rfd6 = allocate_rfd(AF_INET6);
+- fd = forward->rfd6->fd;
++ if (forward->rfd6 || (forward->rfd6 = allocate_rfd(AF_INET6)))
++ fd = forward->rfd6->fd;
+ }
+ else
+ {
+ /* may have changed family */
+- if (!forward->rfd4)
+- forward->rfd4 = allocate_rfd(AF_INET);
+- fd = forward->rfd4->fd;
++ if (forward->rfd4 || (forward->rfd4 = allocate_rfd(AF_INET)))
++ fd = forward->rfd4->fd;
+ }
+ }
+
++ /* Can't get socket. */
++ if (fd == -1)
++ return;
++
+ while (retry_send(sendto(fd, (char *)header, plen, 0,
+ &start->addr.sa,
+ sa_len(&start->addr))));
+@@ -2261,7 +2264,6 @@ struct frec *get_new_frec(time_t now, in
+ return f; /* OK if malloc fails and this is NULL */
+ }
+
+-/* crc is all-ones if not known. */
+ static struct frec *lookup_frec(unsigned short id, int fd, int family, void *hash)
+ {
+ struct frec *f;
--- /dev/null
+From 15b60ddf935a531269bb8c68198de012a4967156 Mon Sep 17 00:00:00 2001
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Wed, 18 Nov 2020 18:34:55 +0000
+Subject: Handle multiple identical near simultaneous DNS queries better.
+
+Previously, such queries would all be forwarded
+independently. This is, in theory, inefficent but in practise
+not a problem, _except_ that is means that an answer for any
+of the forwarded queries will be accepted and cached.
+An attacker can send a query multiple times, and for each repeat,
+another {port, ID} becomes capable of accepting the answer he is
+sending in the blind, to random IDs and ports. The chance of a
+succesful attack is therefore multiplied by the number of repeats
+of the query. The new behaviour detects repeated queries and
+merely stores the clients sending repeats so that when the
+first query completes, the answer can be sent to all the
+clients who asked. Refer: CERT VU#434904.
+---
+ CHANGELOG | 16 +++++-
+ src/dnsmasq.h | 19 ++++---
+ src/forward.c | 142 ++++++++++++++++++++++++++++++++++++++++++--------
+ 3 files changed, 147 insertions(+), 30 deletions(-)
+
+--- a/CHANGELOG
++++ b/CHANGELOG
+@@ -4,13 +4,27 @@
+
+ Be sure to only accept UDP DNS query replies at the address
+ from which the query was originated. This keeps as much entropy
+- in the {query-ID, random-port} tuple as possible, help defeat
++ in the {query-ID, random-port} tuple as possible, to help defeat
+ cache poisoning attacks. Refer: CERT VU#434904.
+
+ Use the SHA-256 hash function to verify that DNS answers
+ received are for the questions originally asked. This replaces
+ the slightly insecure SHA-1 (when compiled with DNSSEC) or
+ the very insecure CRC32 (otherwise). Refer: CERT VU#434904.
++
++ Handle multiple identical near simultaneous DNS queries better.
++ Previously, such queries would all be forwarded
++ independently. This is, in theory, inefficent but in practise
++ not a problem, _except_ that is means that an answer for any
++ of the forwarded queries will be accepted and cached.
++ An attacker can send a query multiple times, and for each repeat,
++ another {port, ID} becomes capable of accepting the answer he is
++ sending in the blind, to random IDs and ports. The chance of a
++ succesful attack is therefore multiplied by the number of repeats
++ of the query. The new behaviour detects repeated queries and
++ merely stores the clients sending repeats so that when the
++ first query completes, the answer can be sent to all the
++ clients who asked. Refer: CERT VU#434904.
+
+
+ version 2.81
+--- a/src/dnsmasq.h
++++ b/src/dnsmasq.h
+@@ -642,19 +642,24 @@ struct hostsfile {
+ #define FREC_DO_QUESTION 64
+ #define FREC_ADDED_PHEADER 128
+ #define FREC_TEST_PKTSZ 256
+-#define FREC_HAS_EXTRADATA 512
++#define FREC_HAS_EXTRADATA 512
++#define FREC_HAS_PHEADER 1024
+
+ #define HASH_SIZE 32 /* SHA-256 digest size */
+
+ struct frec {
+- union mysockaddr source;
+- union all_addr dest;
++ struct frec_src {
++ union mysockaddr source;
++ union all_addr dest;
++ unsigned int iface, log_id;
++ unsigned short orig_id;
++ struct frec_src *next;
++ } frec_src;
+ struct server *sentto; /* NULL means free */
+ struct randfd *rfd4;
+ struct randfd *rfd6;
+- unsigned int iface;
+- unsigned short orig_id, new_id;
+- int log_id, fd, forwardall, flags;
++ unsigned short new_id;
++ int fd, forwardall, flags;
+ time_t time;
+ unsigned char *hash[HASH_SIZE];
+ #ifdef HAVE_DNSSEC
+@@ -1069,6 +1074,8 @@ extern struct daemon {
+ int back_to_the_future;
+ #endif
+ struct frec *frec_list;
++ struct frec_src *free_frec_src;
++ int frec_src_count;
+ struct serverfd *sfds;
+ struct irec *interfaces;
+ struct listener *listeners;
+--- a/src/forward.c
++++ b/src/forward.c
+@@ -20,6 +20,8 @@ static struct frec *lookup_frec(unsigned
+ static struct frec *lookup_frec_by_sender(unsigned short id,
+ union mysockaddr *addr,
+ void *hash);
++static struct frec *lookup_frec_by_query(void *hash, unsigned int flags);
++
+ static unsigned short get_id(void);
+ static void free_frec(struct frec *f);
+
+@@ -247,6 +249,7 @@ static int forward_query(int udpfd, unio
+ int type = SERV_DO_DNSSEC, norebind = 0;
+ union all_addr *addrp = NULL;
+ unsigned int flags = 0;
++ unsigned int fwd_flags = 0;
+ struct server *start = NULL;
+ void *hash = hash_questions(header, plen, daemon->namebuff);
+ #ifdef HAVE_DNSSEC
+@@ -255,7 +258,18 @@ static int forward_query(int udpfd, unio
+ unsigned int gotname = extract_request(header, plen, daemon->namebuff, NULL);
+ unsigned char *oph = find_pseudoheader(header, plen, NULL, NULL, NULL, NULL);
+ (void)do_bit;
+-
++
++ if (header->hb4 & HB4_CD)
++ fwd_flags |= FREC_CHECKING_DISABLED;
++ if (ad_reqd)
++ fwd_flags |= FREC_AD_QUESTION;
++ if (oph)
++ fwd_flags |= FREC_HAS_PHEADER;
++#ifdef HAVE_DNSSEC
++ if (do_bit)
++ fwd_flags |= FREC_DO_QUESTION;
++#endif
++
+ /* may be no servers available. */
+ if (forward || (forward = lookup_frec_by_sender(ntohs(header->id), udpaddr, hash)))
+ {
+@@ -328,6 +342,39 @@ static int forward_query(int udpfd, unio
+ }
+ else
+ {
++ /* Query from new source, but the same query may be in progress
++ from another source. If so, just add this client to the
++ list that will get the reply.
++
++ Note that is the EDNS client subnet option is in use, we can't do this,
++ as the clients (and therefore query EDNS options) will be different
++ for each query. The EDNS subnet code has checks to avoid
++ attacks in this case. */
++ if (!option_bool(OPT_CLIENT_SUBNET) && (forward = lookup_frec_by_query(hash, fwd_flags)))
++ {
++ /* Note whine_malloc() zeros memory. */
++ if (!daemon->free_frec_src &&
++ daemon->frec_src_count < daemon->ftabsize &&
++ (daemon->free_frec_src = whine_malloc(sizeof(struct frec_src))))
++ daemon->frec_src_count++;
++
++ /* If we've been spammed with many duplicates, just drop the query. */
++ if (daemon->free_frec_src)
++ {
++ struct frec_src *new = daemon->free_frec_src;
++ daemon->free_frec_src = new->next;
++ new->next = forward->frec_src.next;
++ forward->frec_src.next = new;
++ new->orig_id = ntohs(header->id);
++ new->source = *udpaddr;
++ new->dest = *dst_addr;
++ new->log_id = daemon->log_id;
++ new->iface = dst_iface;
++ }
++
++ return 1;
++ }
++
+ if (gotname)
+ flags = search_servers(now, &addrp, gotname, daemon->namebuff, &type, &domain, &norebind);
+
+@@ -335,22 +382,22 @@ static int forward_query(int udpfd, unio
+ do_dnssec = type & SERV_DO_DNSSEC;
+ #endif
+ type &= ~SERV_DO_DNSSEC;
+-
++
+ if (daemon->servers && !flags)
+ forward = get_new_frec(now, NULL, 0);
+ /* table full - flags == 0, return REFUSED */
+
+ if (forward)
+ {
+- forward->source = *udpaddr;
+- forward->dest = *dst_addr;
+- forward->iface = dst_iface;
+- forward->orig_id = ntohs(header->id);
++ forward->frec_src.source = *udpaddr;
++ forward->frec_src.orig_id = ntohs(header->id);
++ forward->frec_src.dest = *dst_addr;
++ forward->frec_src.iface = dst_iface;
+ forward->new_id = get_id();
+ forward->fd = udpfd;
+ memcpy(forward->hash, hash, HASH_SIZE);
+ forward->forwardall = 0;
+- forward->flags = 0;
++ forward->flags = fwd_flags;
+ if (norebind)
+ forward->flags |= FREC_NOREBIND;
+ if (header->hb4 & HB4_CD)
+@@ -405,9 +452,9 @@ static int forward_query(int udpfd, unio
+ unsigned char *pheader;
+
+ /* If a query is retried, use the log_id for the retry when logging the answer. */
+- forward->log_id = daemon->log_id;
++ forward->frec_src.log_id = daemon->log_id;
+
+- plen = add_edns0_config(header, plen, ((unsigned char *)header) + PACKETSZ, &forward->source, now, &subnet);
++ plen = add_edns0_config(header, plen, ((unsigned char *)header) + PACKETSZ, &forward->frec_src.source, now, &subnet);
+
+ if (subnet)
+ forward->flags |= FREC_HAS_SUBNET;
+@@ -544,7 +591,7 @@ static int forward_query(int udpfd, unio
+ return 1;
+
+ /* could not send on, prepare to return */
+- header->id = htons(forward->orig_id);
++ header->id = htons(forward->frec_src.orig_id);
+ free_frec(forward); /* cancel */
+ }
+
+@@ -796,8 +843,8 @@ void reply_query(int fd, int family, tim
+
+ /* log_query gets called indirectly all over the place, so
+ pass these in global variables - sorry. */
+- daemon->log_display_id = forward->log_id;
+- daemon->log_source_addr = &forward->source;
++ daemon->log_display_id = forward->frec_src.log_id;
++ daemon->log_source_addr = &forward->frec_src.source;
+
+ if (daemon->ignore_addr && RCODE(header) == NOERROR &&
+ check_for_ignored_address(header, n, daemon->ignore_addr))
+@@ -1065,6 +1112,7 @@ void reply_query(int fd, int family, tim
+ new->sentto = server;
+ new->rfd4 = NULL;
+ new->rfd6 = NULL;
++ new->frec_src.next = NULL;
+ new->flags &= ~(FREC_DNSKEY_QUERY | FREC_DS_QUERY | FREC_HAS_EXTRADATA);
+ new->forwardall = 0;
+
+@@ -1199,9 +1247,11 @@ void reply_query(int fd, int family, tim
+
+ if ((nn = process_reply(header, now, forward->sentto, (size_t)n, check_rebind, no_cache_dnssec, cache_secure, bogusanswer,
+ forward->flags & FREC_AD_QUESTION, forward->flags & FREC_DO_QUESTION,
+- forward->flags & FREC_ADDED_PHEADER, forward->flags & FREC_HAS_SUBNET, &forward->source)))
++ forward->flags & FREC_ADDED_PHEADER, forward->flags & FREC_HAS_SUBNET, &forward->frec_src.source)))
+ {
+- header->id = htons(forward->orig_id);
++ struct frec_src *src;
++
++ header->id = htons(forward->frec_src.orig_id);
+ header->hb4 |= HB4_RA; /* recursion if available */
+ #ifdef HAVE_DNSSEC
+ /* We added an EDNSO header for the purpose of getting DNSSEC RRs, and set the value of the UDP payload size
+@@ -1217,13 +1267,26 @@ void reply_query(int fd, int family, tim
+ }
+ #endif
+
++ for (src = &forward->frec_src; src; src = src->next)
++ {
++ header->id = htons(src->orig_id);
++
+ #ifdef HAVE_DUMPFILE
+- dump_packet(DUMP_REPLY, daemon->packet, (size_t)nn, NULL, &forward->source);
++ dump_packet(DUMP_REPLY, daemon->packet, (size_t)nn, NULL, &src->source);
+ #endif
+-
+- send_from(forward->fd, option_bool(OPT_NOWILD) || option_bool (OPT_CLEVERBIND), daemon->packet, nn,
+- &forward->source, &forward->dest, forward->iface);
++
++ send_from(forward->fd, option_bool(OPT_NOWILD) || option_bool (OPT_CLEVERBIND), daemon->packet, nn,
++ &src->source, &src->dest, src->iface);
++
++ if (option_bool(OPT_EXTRALOG) && src != &forward->frec_src)
++ {
++ daemon->log_display_id = src->log_id;
++ daemon->log_source_addr = &src->source;
++ log_query(F_UPSTREAM, "query", NULL, "duplicate");
++ }
++ }
+ }
++
+ free_frec(forward); /* cancel */
+ }
+ }
+@@ -2153,6 +2216,17 @@ void free_rfd(struct randfd *rfd)
+
+ static void free_frec(struct frec *f)
+ {
++ struct frec_src *src, *tmp;
++
++ /* add back to freelist of not the record builtin to every frec. */
++ for (src = f->frec_src.next; src; src = tmp)
++ {
++ tmp = src->next;
++ src->next = daemon->free_frec_src;
++ daemon->free_frec_src = src;
++ }
++
++ f->frec_src.next = NULL;
+ free_rfd(f->rfd4);
+ f->rfd4 = NULL;
+ f->sentto = NULL;
+@@ -2292,17 +2366,39 @@ static struct frec *lookup_frec_by_sende
+ void *hash)
+ {
+ struct frec *f;
++ struct frec_src *src;
++
++ for (f = daemon->frec_list; f; f = f->next)
++ if (f->sentto &&
++ !(f->flags & (FREC_DNSKEY_QUERY | FREC_DS_QUERY)) &&
++ memcmp(hash, f->hash, HASH_SIZE) == 0)
++ for (src = &f->frec_src; src; src = src->next)
++ if (src->orig_id == id &&
++ sockaddr_isequal(&src->source, addr))
++ return f;
++
++ return NULL;
++}
++
++static struct frec *lookup_frec_by_query(void *hash, unsigned int flags)
++{
++ struct frec *f;
++
++ /* FREC_DNSKEY and FREC_DS_QUERY are never set in flags, so the test below
++ ensures that no frec created for internal DNSSEC query can be returned here. */
++
++#define FLAGMASK (FREC_CHECKING_DISABLED | FREC_AD_QUESTION | FREC_DO_QUESTION \
++ | FREC_HAS_PHEADER | FREC_DNSKEY_QUERY | FREC_DS_QUERY)
+
+ for(f = daemon->frec_list; f; f = f->next)
+ if (f->sentto &&
+- f->orig_id == id &&
+- memcmp(hash, f->hash, HASH_SIZE) == 0 &&
+- sockaddr_isequal(&f->source, addr))
++ (f->flags & FLAGMASK) == flags &&
++ memcmp(hash, f->hash, HASH_SIZE) == 0)
+ return f;
+-
++
+ return NULL;
+ }
+-
++
+ /* Send query packet again, if we can. */
+ void resend_query()
+ {
--- /dev/null
+From 25e63f1e56f5acdcf91893a1b92ad1e0f2f552d8 Mon Sep 17 00:00:00 2001
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Wed, 25 Nov 2020 21:17:52 +0000
+Subject: Handle caching with EDNS options better.
+
+If we add the EDNS client subnet option, or the client's
+MAC address, then the reply we get back may very depending on
+that. Since the cache is ignorant of such things, it's not safe to
+cache such replies. This patch determines when a dangerous EDNS
+option is being added and disables caching.
+
+Note that for much the same reason, we can't combine multiple
+queries for the same question when dangerous EDNS options are
+being added, and the code now handles that in the same way. This
+query combining is required for security against cache poisoning,
+so disabling the cache has a security function as well as a
+correctness one.
+---
+ man/dnsmasq.8 | 4 +--
+ src/dnsmasq.h | 3 ++-
+ src/edns0.c | 75 ++++++++++++++++++++++++++++++++-------------------
+ src/forward.c | 41 ++++++++++++++++++----------
+ 4 files changed, 78 insertions(+), 45 deletions(-)
+
+--- a/man/dnsmasq.8
++++ b/man/dnsmasq.8
+@@ -690,8 +690,8 @@ still marks the request so that no upstr
+ address information either. The default is zero for both IPv4 and
+ IPv6. Note that upstream nameservers may be configured to return
+ different results based on this information, but the dnsmasq cache
+-does not take account. If a dnsmasq instance is configured such that
+-different results may be encountered, caching should be disabled.
++does not take account. Caching is therefore disabled for such replies,
++unless the subnet address being added is constant.
+
+ For example,
+ .B --add-subnet=24,96
+--- a/src/dnsmasq.h
++++ b/src/dnsmasq.h
+@@ -644,6 +644,7 @@ struct hostsfile {
+ #define FREC_TEST_PKTSZ 256
+ #define FREC_HAS_EXTRADATA 512
+ #define FREC_HAS_PHEADER 1024
++#define FREC_NO_CACHE 2048
+
+ #define HASH_SIZE 32 /* SHA-256 digest size */
+
+@@ -1628,7 +1629,7 @@ size_t add_pseudoheader(struct dns_heade
+ unsigned short udp_sz, int optno, unsigned char *opt, size_t optlen, int set_do, int replace);
+ size_t add_do_bit(struct dns_header *header, size_t plen, unsigned char *limit);
+ size_t add_edns0_config(struct dns_header *header, size_t plen, unsigned char *limit,
+- union mysockaddr *source, time_t now, int *check_subnet);
++ union mysockaddr *source, time_t now, int *check_subnet, int *cacheable);
+ int check_source(struct dns_header *header, size_t plen, unsigned char *pseudoheader, union mysockaddr *peer);
+
+ /* arp.c */
+--- a/src/edns0.c
++++ b/src/edns0.c
+@@ -264,7 +264,8 @@ static void encoder(unsigned char *in, c
+ out[3] = char64(in[2]);
+ }
+
+-static size_t add_dns_client(struct dns_header *header, size_t plen, unsigned char *limit, union mysockaddr *l3, time_t now)
++static size_t add_dns_client(struct dns_header *header, size_t plen, unsigned char *limit,
++ union mysockaddr *l3, time_t now, int *cacheablep)
+ {
+ int maclen, replace = 2; /* can't get mac address, just delete any incoming. */
+ unsigned char mac[DHCP_CHADDR_MAX];
+@@ -273,6 +274,7 @@ static size_t add_dns_client(struct dns_
+ if ((maclen = find_mac(l3, mac, 1, now)) == 6)
+ {
+ replace = 1;
++ *cacheablep = 0;
+
+ if (option_bool(OPT_MAC_HEX))
+ print_mac(encode, mac, maclen);
+@@ -288,14 +290,18 @@ static size_t add_dns_client(struct dns_
+ }
+
+
+-static size_t add_mac(struct dns_header *header, size_t plen, unsigned char *limit, union mysockaddr *l3, time_t now)
++static size_t add_mac(struct dns_header *header, size_t plen, unsigned char *limit,
++ union mysockaddr *l3, time_t now, int *cacheablep)
+ {
+ int maclen;
+ unsigned char mac[DHCP_CHADDR_MAX];
+
+ if ((maclen = find_mac(l3, mac, 1, now)) != 0)
+- plen = add_pseudoheader(header, plen, limit, PACKETSZ, EDNS0_OPTION_MAC, mac, maclen, 0, 0);
+-
++ {
++ *cacheablep = 0;
++ plen = add_pseudoheader(header, plen, limit, PACKETSZ, EDNS0_OPTION_MAC, mac, maclen, 0, 0);
++ }
++
+ return plen;
+ }
+
+@@ -313,17 +319,18 @@ static void *get_addrp(union mysockaddr
+ return &addr->in.sin_addr;
+ }
+
+-static size_t calc_subnet_opt(struct subnet_opt *opt, union mysockaddr *source)
++static size_t calc_subnet_opt(struct subnet_opt *opt, union mysockaddr *source, int *cacheablep)
+ {
+ /* http://tools.ietf.org/html/draft-vandergaast-edns-client-subnet-02 */
+
+ int len;
+ void *addrp = NULL;
+ int sa_family = source->sa.sa_family;
+-
++ int cacheable = 0;
++
+ opt->source_netmask = 0;
+ opt->scope_netmask = 0;
+-
++
+ if (source->sa.sa_family == AF_INET6 && daemon->add_subnet6)
+ {
+ opt->source_netmask = daemon->add_subnet6->mask;
+@@ -331,6 +338,7 @@ static size_t calc_subnet_opt(struct sub
+ {
+ sa_family = daemon->add_subnet6->addr.sa.sa_family;
+ addrp = get_addrp(&daemon->add_subnet6->addr, sa_family);
++ cacheable = 1;
+ }
+ else
+ addrp = &source->in6.sin6_addr;
+@@ -343,6 +351,7 @@ static size_t calc_subnet_opt(struct sub
+ {
+ sa_family = daemon->add_subnet4->addr.sa.sa_family;
+ addrp = get_addrp(&daemon->add_subnet4->addr, sa_family);
++ cacheable = 1; /* Address is constant */
+ }
+ else
+ addrp = &source->in.sin_addr;
+@@ -350,8 +359,6 @@ static size_t calc_subnet_opt(struct sub
+
+ opt->family = htons(sa_family == AF_INET6 ? 2 : 1);
+
+- len = 0;
+-
+ if (addrp && opt->source_netmask != 0)
+ {
+ len = ((opt->source_netmask - 1) >> 3) + 1;
+@@ -359,18 +366,26 @@ static size_t calc_subnet_opt(struct sub
+ if (opt->source_netmask & 7)
+ opt->addr[len-1] &= 0xff << (8 - (opt->source_netmask & 7));
+ }
++ else
++ {
++ cacheable = 1; /* No address ever supplied. */
++ len = 0;
++ }
++
++ if (cacheablep)
++ *cacheablep = cacheable;
+
+ return len + 4;
+ }
+
+-static size_t add_source_addr(struct dns_header *header, size_t plen, unsigned char *limit, union mysockaddr *source)
++static size_t add_source_addr(struct dns_header *header, size_t plen, unsigned char *limit, union mysockaddr *source, int *cacheable)
+ {
+ /* http://tools.ietf.org/html/draft-vandergaast-edns-client-subnet-02 */
+
+ int len;
+ struct subnet_opt opt;
+
+- len = calc_subnet_opt(&opt, source);
++ len = calc_subnet_opt(&opt, source, cacheable);
+ return add_pseudoheader(header, plen, (unsigned char *)limit, PACKETSZ, EDNS0_OPTION_CLIENT_SUBNET, (unsigned char *)&opt, len, 0, 0);
+ }
+
+@@ -383,18 +398,18 @@ int check_source(struct dns_header *head
+ unsigned char *p;
+ int code, i, rdlen;
+
+- calc_len = calc_subnet_opt(&opt, peer);
+-
+- if (!(p = skip_name(pseudoheader, header, plen, 10)))
+- return 1;
+-
+- p += 8; /* skip UDP length and RCODE */
++ calc_len = calc_subnet_opt(&opt, peer, NULL);
+
+- GETSHORT(rdlen, p);
+- if (!CHECK_LEN(header, p, plen, rdlen))
+- return 1; /* bad packet */
+-
+- /* check if option there */
++ if (!(p = skip_name(pseudoheader, header, plen, 10)))
++ return 1;
++
++ p += 8; /* skip UDP length and RCODE */
++
++ GETSHORT(rdlen, p);
++ if (!CHECK_LEN(header, p, plen, rdlen))
++ return 1; /* bad packet */
++
++ /* check if option there */
+ for (i = 0; i + 4 < rdlen; i += len + 4)
+ {
+ GETSHORT(code, p);
+@@ -412,24 +427,28 @@ int check_source(struct dns_header *head
+ return 1;
+ }
+
++/* Set *check_subnet if we add a client subnet option, which needs to checked
++ in the reply. Set *cacheable to zero if we add an option which the answer
++ may depend on. */
+ size_t add_edns0_config(struct dns_header *header, size_t plen, unsigned char *limit,
+- union mysockaddr *source, time_t now, int *check_subnet)
++ union mysockaddr *source, time_t now, int *check_subnet, int *cacheable)
+ {
+ *check_subnet = 0;
+-
++ *cacheable = 1;
++
+ if (option_bool(OPT_ADD_MAC))
+- plen = add_mac(header, plen, limit, source, now);
++ plen = add_mac(header, plen, limit, source, now, cacheable);
+
+ if (option_bool(OPT_MAC_B64) || option_bool(OPT_MAC_HEX))
+- plen = add_dns_client(header, plen, limit, source, now);
+-
++ plen = add_dns_client(header, plen, limit, source, now, cacheable);
++
+ if (daemon->dns_client_id)
+ plen = add_pseudoheader(header, plen, limit, PACKETSZ, EDNS0_OPTION_NOMCPEID,
+ (unsigned char *)daemon->dns_client_id, strlen(daemon->dns_client_id), 0, 1);
+
+ if (option_bool(OPT_CLIENT_SUBNET))
+ {
+- plen = add_source_addr(header, plen, limit, source);
++ plen = add_source_addr(header, plen, limit, source, cacheable);
+ *check_subnet = 1;
+ }
+
+--- a/src/forward.c
++++ b/src/forward.c
+@@ -344,13 +344,10 @@ static int forward_query(int udpfd, unio
+ {
+ /* Query from new source, but the same query may be in progress
+ from another source. If so, just add this client to the
+- list that will get the reply.
++ list that will get the reply.*/
+
+- Note that is the EDNS client subnet option is in use, we can't do this,
+- as the clients (and therefore query EDNS options) will be different
+- for each query. The EDNS subnet code has checks to avoid
+- attacks in this case. */
+- if (!option_bool(OPT_CLIENT_SUBNET) && (forward = lookup_frec_by_query(hash, fwd_flags)))
++ if (!option_bool(OPT_ADD_MAC) && !option_bool(OPT_MAC_B64) &&
++ (forward = lookup_frec_by_query(hash, fwd_flags)))
+ {
+ /* Note whine_malloc() zeros memory. */
+ if (!daemon->free_frec_src &&
+@@ -447,18 +444,21 @@ static int forward_query(int udpfd, unio
+ if (!flags && forward)
+ {
+ struct server *firstsentto = start;
+- int subnet, forwarded = 0;
++ int subnet, cacheable, forwarded = 0;
+ size_t edns0_len;
+ unsigned char *pheader;
+
+ /* If a query is retried, use the log_id for the retry when logging the answer. */
+ forward->frec_src.log_id = daemon->log_id;
+
+- plen = add_edns0_config(header, plen, ((unsigned char *)header) + PACKETSZ, &forward->frec_src.source, now, &subnet);
++ plen = add_edns0_config(header, plen, ((unsigned char *)header) + PACKETSZ, &forward->frec_src.source, now, &subnet, &cacheable);
+
+ if (subnet)
+ forward->flags |= FREC_HAS_SUBNET;
+-
++
++ if (!cacheable)
++ forward->flags |= FREC_NO_CACHE;
++
+ #ifdef HAVE_DNSSEC
+ if (option_bool(OPT_DNSSEC_VALID) && do_dnssec)
+ {
+@@ -642,7 +642,7 @@ static size_t process_reply(struct dns_h
+ }
+ }
+ #endif
+-
++
+ if ((pheader = find_pseudoheader(header, n, &plen, &sizep, &is_sign, NULL)))
+ {
+ /* Get extended RCODE. */
+@@ -1244,6 +1244,11 @@ void reply_query(int fd, int family, tim
+ header->hb4 |= HB4_CD;
+ else
+ header->hb4 &= ~HB4_CD;
++
++ /* Never cache answers which are contingent on the source or MAC address EDSN0 option,
++ since the cache is ignorant of such things. */
++ if (forward->flags & FREC_NO_CACHE)
++ no_cache_dnssec = 1;
+
+ if ((nn = process_reply(header, now, forward->sentto, (size_t)n, check_rebind, no_cache_dnssec, cache_secure, bogusanswer,
+ forward->flags & FREC_AD_QUESTION, forward->flags & FREC_DO_QUESTION,
+@@ -1788,7 +1793,7 @@ unsigned char *tcp_request(int confd, ti
+ int local_auth = 0;
+ #endif
+ int checking_disabled, do_bit, added_pheader = 0, have_pseudoheader = 0;
+- int check_subnet, no_cache_dnssec = 0, cache_secure = 0, bogusanswer = 0;
++ int check_subnet, cacheable, no_cache_dnssec = 0, cache_secure = 0, bogusanswer = 0;
+ size_t m;
+ unsigned short qtype;
+ unsigned int gotname;
+@@ -1959,7 +1964,7 @@ unsigned char *tcp_request(int confd, ti
+ char *domain = NULL;
+ unsigned char *oph = find_pseudoheader(header, size, NULL, NULL, NULL, NULL);
+
+- size = add_edns0_config(header, size, ((unsigned char *) header) + 65536, &peer_addr, now, &check_subnet);
++ size = add_edns0_config(header, size, ((unsigned char *) header) + 65536, &peer_addr, now, &check_subnet, &cacheable);
+
+ if (gotname)
+ flags = search_servers(now, &addrp, gotname, daemon->namebuff, &type, &domain, &norebind);
+@@ -2122,6 +2127,11 @@ unsigned char *tcp_request(int confd, ti
+ break;
+ }
+
++ /* Never cache answers which are contingent on the source or MAC address EDSN0 option,
++ since the cache is ignorant of such things. */
++ if (!cacheable)
++ no_cache_dnssec = 1;
++
+ m = process_reply(header, now, last_server, (unsigned int)m,
+ option_bool(OPT_NO_REBIND) && !norebind, no_cache_dnssec, cache_secure, bogusanswer,
+ ad_reqd, do_bit, added_pheader, check_subnet, &peer_addr);
+@@ -2385,10 +2395,13 @@ static struct frec *lookup_frec_by_query
+ struct frec *f;
+
+ /* FREC_DNSKEY and FREC_DS_QUERY are never set in flags, so the test below
+- ensures that no frec created for internal DNSSEC query can be returned here. */
++ ensures that no frec created for internal DNSSEC query can be returned here.
++
++ Similarly FREC_NO_CACHE is never set in flags, so a query which is
++ contigent on a particular source address EDNS0 option will never be matched. */
+
+ #define FLAGMASK (FREC_CHECKING_DISABLED | FREC_AD_QUESTION | FREC_DO_QUESTION \
+- | FREC_HAS_PHEADER | FREC_DNSKEY_QUERY | FREC_DS_QUERY)
++ | FREC_HAS_PHEADER | FREC_DNSKEY_QUERY | FREC_DS_QUERY | FREC_NO_CACHE)
+
+ for(f = daemon->frec_list; f; f = f->next)
+ if (f->sentto &&
--- /dev/null
+From 2024f9729713fd657d65e64c2e4e471baa0a3e5b Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Petr=20Men=C5=A1=C3=ADk?= <pemensik@redhat.com>
+Date: Wed, 25 Nov 2020 17:18:55 +0100
+Subject: Support hash function from nettle (only)
+
+Unlike COPTS=-DHAVE_DNSSEC, allow usage of just sha256 function from
+nettle, but keep DNSSEC disabled at build time. Skips use of internal
+hash implementation without support for validation built-in.
+---
+ Makefile | 8 +++++---
+ bld/pkg-wrapper | 41 ++++++++++++++++++++++-------------------
+ src/config.h | 8 ++++++++
+ src/crypto.c | 7 +++++++
+ src/dnsmasq.h | 2 +-
+ src/hash_questions.c | 2 +-
+ 6 files changed, 44 insertions(+), 24 deletions(-)
+
+--- a/Makefile
++++ b/Makefile
+@@ -53,7 +53,7 @@ top?=$(CURDIR)
+
+ dbus_cflags = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_DBUS $(PKG_CONFIG) --cflags dbus-1`
+ dbus_libs = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_DBUS $(PKG_CONFIG) --libs dbus-1`
+-ubus_libs = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_UBUS "" --copy -lubox -lubus`
++ubus_libs = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_UBUS "" --copy '-lubox -lubus'`
+ idn_cflags = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_IDN $(PKG_CONFIG) --cflags libidn`
+ idn_libs = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_IDN $(PKG_CONFIG) --libs libidn`
+ idn2_cflags = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_LIBIDN2 $(PKG_CONFIG) --cflags libidn2`
+@@ -62,8 +62,10 @@ ct_cflags = `echo $(COPTS) | $(top)/
+ ct_libs = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_CONNTRACK $(PKG_CONFIG) --libs libnetfilter_conntrack`
+ lua_cflags = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_LUASCRIPT $(PKG_CONFIG) --cflags lua5.2`
+ lua_libs = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_LUASCRIPT $(PKG_CONFIG) --libs lua5.2`
+-nettle_cflags = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_DNSSEC $(PKG_CONFIG) --cflags nettle hogweed`
+-nettle_libs = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_DNSSEC $(PKG_CONFIG) --libs nettle hogweed`
++nettle_cflags = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_DNSSEC $(PKG_CONFIG) --cflags 'nettle hogweed' \
++ HAVE_NETTLEHASH $(PKG_CONFIG) --cflags nettle`
++nettle_libs = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_DNSSEC $(PKG_CONFIG) --libs 'nettle hogweed' \
++ HAVE_NETTLEHASH $(PKG_CONFIG) --libs nettle`
+ gmp_libs = `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_DNSSEC NO_GMP --copy -lgmp`
+ sunos_libs = `if uname | grep SunOS >/dev/null 2>&1; then echo -lsocket -lnsl -lposix4; fi`
+ version = -DVERSION='\"`$(top)/bld/get-version $(top)`\"'
+--- a/bld/pkg-wrapper
++++ b/bld/pkg-wrapper
+@@ -1,35 +1,37 @@
+ #!/bin/sh
+
+-search=$1
+-shift
+-pkg=$1
+-shift
+-op=$1
+-shift
+-
+ in=`cat`
+
+-if grep "^\#[[:space:]]*define[[:space:]]*$search" config.h >/dev/null 2>&1 || \
+- echo $in | grep $search >/dev/null 2>&1; then
++search()
++{
++ grep "^\#[[:space:]]*define[[:space:]]*$1" config.h >/dev/null 2>&1 || \
++ echo $in | grep $1 >/dev/null 2>&1
++}
++
++while [ "$#" -gt 0 ]; do
++ search=$1
++ pkg=$2
++ op=$3
++ lib=$4
++ shift 4
++if search "$search"; then
++
+ # Nasty, nasty, in --copy, arg 2 (if non-empty) is another config to search for, used with NO_GMP
+ if [ $op = "--copy" ]; then
+ if [ -z "$pkg" ]; then
+- pkg="$*"
+- elif grep "^\#[[:space:]]*define[[:space:]]*$pkg" config.h >/dev/null 2>&1 || \
+- echo $in | grep $pkg >/dev/null 2>&1; then
++ pkg="$lib"
++ elif search "$pkg"; then
+ pkg=""
+ else
+- pkg="$*"
++ pkg="$lib"
+ fi
+- elif grep "^\#[[:space:]]*define[[:space:]]*${search}_STATIC" config.h >/dev/null 2>&1 || \
+- echo $in | grep ${search}_STATIC >/dev/null 2>&1; then
+- pkg=`$pkg --static $op $*`
++ elif search "${search}_STATIC"; then
++ pkg=`$pkg --static $op $lib`
+ else
+- pkg=`$pkg $op $*`
++ pkg=`$pkg $op $lib`
+ fi
+
+- if grep "^\#[[:space:]]*define[[:space:]]*${search}_STATIC" config.h >/dev/null 2>&1 || \
+- echo $in | grep ${search}_STATIC >/dev/null 2>&1; then
++ if search "${search}_STATIC"; then
+ if [ $op = "--libs" ] || [ $op = "--copy" ]; then
+ echo "-Wl,-Bstatic $pkg -Wl,-Bdynamic"
+ else
+@@ -40,3 +42,4 @@ if grep "^\#[[:space:]]*define[[:space:]
+ fi
+ fi
+
++done
+--- a/src/config.h
++++ b/src/config.h
+@@ -117,6 +117,9 @@ HAVE_AUTH
+ define this to include the facility to act as an authoritative DNS
+ server for one or more zones.
+
++HAVE_NETTLEHASH
++ include just hash function from nettle, but no DNSSEC.
++
+ HAVE_DNSSEC
+ include DNSSEC validator.
+
+@@ -184,6 +187,7 @@ RESOLVFILE
+ /* #define HAVE_IDN */
+ /* #define HAVE_LIBIDN2 */
+ /* #define HAVE_CONNTRACK */
++/* #define HAVE_NETTLEHASH */
+ /* #define HAVE_DNSSEC */
+
+
+@@ -408,6 +412,10 @@ static char *compile_opts =
+ "no-"
+ #endif
+ "auth "
++#if !defined(HAVE_NETTLEHASH) && !defined(HAVE_DNSSEC)
++"no-"
++#endif
++"nettlehash "
+ #ifndef HAVE_DNSSEC
+ "no-"
+ #endif
+--- a/src/crypto.c
++++ b/src/crypto.c
+@@ -23,6 +23,9 @@
+ #include <nettle/ecdsa.h>
+ #include <nettle/ecc-curve.h>
+ #include <nettle/eddsa.h>
++#endif
++
++#if defined(HAVE_DNSSEC) || defined(HAVE_NETTLEHASH)
+ #include <nettle/nettle-meta.h>
+ #include <nettle/bignum.h>
+
+@@ -165,6 +168,10 @@ int hash_init(const struct nettle_hash *
+
+ return 1;
+ }
++
++#endif
++
++#ifdef HAVE_DNSSEC
+
+ static int dnsmasq_rsa_verify(struct blockdata *key_data, unsigned int key_len, unsigned char *sig, size_t sig_len,
+ unsigned char *digest, size_t digest_len, int algo)
+--- a/src/dnsmasq.h
++++ b/src/dnsmasq.h
+@@ -150,7 +150,7 @@ extern int capget(cap_user_header_t head
+ #include <priv.h>
+ #endif
+
+-#ifdef HAVE_DNSSEC
++#if defined(HAVE_DNSSEC) || defined(HAVE_NETTLEHASH)
+ # include <nettle/nettle-meta.h>
+ #endif
+
+--- a/src/hash_questions.c
++++ b/src/hash_questions.c
+@@ -28,7 +28,7 @@
+
+ #include "dnsmasq.h"
+
+-#ifdef HAVE_DNSSEC
++#if defined(HAVE_DNSSEC) || defined(HAVE_NETTLEHASH)
+ unsigned char *hash_questions(struct dns_header *header, size_t plen, char *name)
+ {
+ int q;
--- /dev/null
+From 6a6e06fbb0d4690507ceaf2bb6f0d8910f3d4914 Mon Sep 17 00:00:00 2001
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Fri, 4 Dec 2020 18:35:11 +0000
+Subject: Small cleanups in frec_src datastucture handling.
+
+---
+ src/forward.c | 22 +++++++++++++---------
+ 1 file changed, 13 insertions(+), 9 deletions(-)
+
+--- a/src/forward.c
++++ b/src/forward.c
+@@ -353,7 +353,10 @@ static int forward_query(int udpfd, unio
+ if (!daemon->free_frec_src &&
+ daemon->frec_src_count < daemon->ftabsize &&
+ (daemon->free_frec_src = whine_malloc(sizeof(struct frec_src))))
+- daemon->frec_src_count++;
++ {
++ daemon->frec_src_count++;
++ daemon->free_frec_src->next = NULL;
++ }
+
+ /* If we've been spammed with many duplicates, just drop the query. */
+ if (daemon->free_frec_src)
+@@ -390,6 +393,7 @@ static int forward_query(int udpfd, unio
+ forward->frec_src.orig_id = ntohs(header->id);
+ forward->frec_src.dest = *dst_addr;
+ forward->frec_src.iface = dst_iface;
++ forward->frec_src.next = NULL;
+ forward->new_id = get_id();
+ forward->fd = udpfd;
+ memcpy(forward->hash, hash, HASH_SIZE);
+@@ -2226,16 +2230,16 @@ void free_rfd(struct randfd *rfd)
+
+ static void free_frec(struct frec *f)
+ {
+- struct frec_src *src, *tmp;
+-
+- /* add back to freelist of not the record builtin to every frec. */
+- for (src = f->frec_src.next; src; src = tmp)
++ struct frec_src *last;
++
++ /* add back to freelist if not the record builtin to every frec. */
++ for (last = f->frec_src.next; last && last->next; last = last->next) ;
++ if (last)
+ {
+- tmp = src->next;
+- src->next = daemon->free_frec_src;
+- daemon->free_frec_src = src;
++ last->next = daemon->free_frec_src;
++ daemon->free_frec_src = f->frec_src.next;
+ }
+-
++
+ f->frec_src.next = NULL;
+ free_rfd(f->rfd4);
+ f->rfd4 = NULL;
--- /dev/null
+From e01e09c7125b40646aff4a582672e711a18a69a4 Mon Sep 17 00:00:00 2001
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Fri, 8 Jan 2021 22:50:03 +0000
+Subject: Add CVE numbers to security update descriptions in CHANGELOG
+
+---
+ CHANGELOG | 9 +++++----
+ 1 file changed, 5 insertions(+), 4 deletions(-)
+
+--- a/CHANGELOG
++++ b/CHANGELOG
+@@ -1,16 +1,17 @@
+ Fix a remote buffer overflow problem in the DNSSEC code. Any
+ dnsmasq with DNSSEC compiled in and enabled is vulnerable to this,
+- referenced by CERT VU#434904.
++ referenced by CVE-2020-25681, CVE-2020-25682, CVE-2020-25683
++ CVE-2020-25687.
+
+ Be sure to only accept UDP DNS query replies at the address
+ from which the query was originated. This keeps as much entropy
+ in the {query-ID, random-port} tuple as possible, to help defeat
+- cache poisoning attacks. Refer: CERT VU#434904.
++ cache poisoning attacks. Refer: CVE-2020-25684.
+
+ Use the SHA-256 hash function to verify that DNS answers
+ received are for the questions originally asked. This replaces
+ the slightly insecure SHA-1 (when compiled with DNSSEC) or
+- the very insecure CRC32 (otherwise). Refer: CERT VU#434904.
++ the very insecure CRC32 (otherwise). Refer: CVE-2020-25685.
+
+ Handle multiple identical near simultaneous DNS queries better.
+ Previously, such queries would all be forwarded
+@@ -24,7 +25,7 @@
+ of the query. The new behaviour detects repeated queries and
+ merely stores the clients sending repeats so that when the
+ first query completes, the answer can be sent to all the
+- clients who asked. Refer: CERT VU#434904.
++ clients who asked. Refer: CVE-2020-25686.
+
+
+ version 2.81
--- /dev/null
+From 503f68dbc437df20a45aab440e6fad92062af229 Mon Sep 17 00:00:00 2001
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Fri, 15 Jan 2021 21:53:29 +0000
+Subject: Fix warning message logic.
+
+---
+ src/hash_questions.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/src/hash_questions.c
++++ b/src/hash_questions.c
+@@ -43,7 +43,7 @@ unsigned char *hash_questions(struct dns
+ static unsigned char dummy[HASH_SIZE];
+ static int warned = 0;
+
+- if (warned)
++ if (!warned)
+ my_syslog(LOG_ERR, _("Failed to create SHA-256 hash object"));
+ warned = 1;
+
--- /dev/null
+From cc0b4489c782f6b90ca118abb18e716a7a831289 Mon Sep 17 00:00:00 2001
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Fri, 15 Jan 2021 22:21:52 +0000
+Subject: Update to new struct frec fields in conntrack code.
+
+---
+ src/forward.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/src/forward.c
++++ b/src/forward.c
+@@ -530,7 +530,7 @@ static int forward_query(int udpfd, unio
+ if (option_bool(OPT_CONNTRACK))
+ {
+ unsigned int mark;
+- if (get_incoming_mark(&forward->source, &forward->dest, 0, &mark))
++ if (get_incoming_mark(&forward->frec_src.source, &forward->frec_src.dest, 0, &mark))
+ setsockopt(fd, SOL_SOCKET, SO_MARK, &mark, sizeof(unsigned int));
+ }
+ #endif
+@@ -1178,7 +1178,7 @@ void reply_query(int fd, int family, tim
+ if (option_bool(OPT_CONNTRACK))
+ {
+ unsigned int mark;
+- if (get_incoming_mark(&orig->source, &orig->dest, 0, &mark))
++ if (get_incoming_mark(&orig->frec_src.source, &orig->frec_src.dest, 0, &mark))
+ setsockopt(fd, SOL_SOCKET, SO_MARK, &mark, sizeof(unsigned int));
+ }
+ #endif
--- a/src/crypto.c
+++ b/src/crypto.c
-@@ -294,7 +294,7 @@ static int dnsmasq_ecdsa_verify(struct b
+@@ -301,7 +301,7 @@ static int dnsmasq_ecdsa_verify(struct b
if (!(key_256 = whine_malloc(sizeof(struct ecc_point))))
return 0;
}
key = key_256;
-@@ -307,7 +307,7 @@ static int dnsmasq_ecdsa_verify(struct b
+@@ -314,7 +314,7 @@ static int dnsmasq_ecdsa_verify(struct b
if (!(key_384 = whine_malloc(sizeof(struct ecc_point))))
return 0;
projects / librecmc / librecmc.git / commitdiff