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@@ -0,0 +1,202 @@
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+From 4fe6744a220eddd3f1749b40cac3dfc510787de6 Mon Sep 17 00:00:00 2001
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+From: Simon Kelley <simon@thekelleys.org.uk>
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+Date: Fri, 19 Jan 2018 12:26:08 +0000
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+Subject: [PATCH] DNSSEC fix for wildcard NSEC records. CVE-2017-15107
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+ applies.
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+
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+It's OK for NSEC records to be expanded from wildcards,
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+but in that case, the proof of non-existence is only valid
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+starting at the wildcard name, *.<domain> NOT the name expanded
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+from the wildcard. Without this check it's possible for an
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+attacker to craft an NSEC which wrongly proves non-existence
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+in a domain which includes a wildcard for NSEC.
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+---
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+ src/dnssec.c | 117 +++++++++++++++++++++++++++++++++++++++++++++++++++-------
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+ 2 files changed, 114 insertions(+), 15 deletions(-)
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+
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+--- a/src/dnssec.c
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++++ b/src/dnssec.c
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+@@ -424,15 +424,17 @@ static void from_wire(char *name)
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+ static int count_labels(char *name)
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+ {
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+ int i;
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+-
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++ char *p;
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++
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+ if (*name == 0)
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+ return 0;
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+
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+- for (i = 0; *name; name++)
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+- if (*name == '.')
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++ for (p = name, i = 0; *p; p++)
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++ if (*p == '.')
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+ i++;
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+
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+- return i+1;
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++ /* Don't count empty first label. */
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++ return *name == '.' ? i : i+1;
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+ }
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+
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+ /* Implement RFC1982 wrapped compare for 32-bit numbers */
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+@@ -1412,8 +1414,8 @@ static int hostname_cmp(const char *a, c
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+ }
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+ }
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+
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+-static int prove_non_existence_nsec(struct dns_header *header, size_t plen, unsigned char **nsecs, int nsec_count,
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+- char *workspace1, char *workspace2, char *name, int type, int *nons)
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++static int prove_non_existence_nsec(struct dns_header *header, size_t plen, unsigned char **nsecs, unsigned char **labels, int nsec_count,
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++ char *workspace1_in, char *workspace2, char *name, int type, int *nons)
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+ {
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+ int i, rc, rdlen;
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+ unsigned char *p, *psave;
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+@@ -1426,6 +1428,9 @@ static int prove_non_existence_nsec(stru
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+ /* Find NSEC record that proves name doesn't exist */
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+ for (i = 0; i < nsec_count; i++)
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+ {
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++ char *workspace1 = workspace1_in;
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++ int sig_labels, name_labels;
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++
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+ p = nsecs[i];
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+ if (!extract_name(header, plen, &p, workspace1, 1, 10))
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+ return 0;
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+@@ -1434,7 +1439,27 @@ static int prove_non_existence_nsec(stru
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+ psave = p;
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+ if (!extract_name(header, plen, &p, workspace2, 1, 10))
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+ return 0;
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+-
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++
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++ /* If NSEC comes from wildcard expansion, use original wildcard
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++ as name for computation. */
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++ sig_labels = *labels[i];
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++ name_labels = count_labels(workspace1);
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++
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++ if (sig_labels < name_labels)
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++ {
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++ int k;
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++ for (k = name_labels - sig_labels; k != 0; k--)
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++ {
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++ while (*workspace1 != '.' && *workspace1 != 0)
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++ workspace1++;
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++ if (k != 1 && *workspace1 == '.')
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++ workspace1++;
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++ }
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++
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++ workspace1--;
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++ *workspace1 = '*';
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++ }
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++
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+ rc = hostname_cmp(workspace1, name);
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+
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+ if (rc == 0)
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+@@ -1832,24 +1857,26 @@ static int prove_non_existence_nsec3(str
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+
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+ static int prove_non_existence(struct dns_header *header, size_t plen, char *keyname, char *name, int qtype, int qclass, char *wildname, int *nons)
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+ {
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+- static unsigned char **nsecset = NULL;
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+- static int nsecset_sz = 0;
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++ static unsigned char **nsecset = NULL, **rrsig_labels = NULL;
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++ static int nsecset_sz = 0, rrsig_labels_sz = 0;
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+
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+ int type_found = 0;
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+- unsigned char *p = skip_questions(header, plen);
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++ unsigned char *auth_start, *p = skip_questions(header, plen);
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+ int type, class, rdlen, i, nsecs_found;
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+
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+ /* Move to NS section */
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+ if (!p || !(p = skip_section(p, ntohs(header->ancount), header, plen)))
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+ return 0;
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++
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++ auth_start = p;
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+
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+ for (nsecs_found = 0, i = ntohs(header->nscount); i != 0; i--)
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+ {
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+ unsigned char *pstart = p;
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+
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+- if (!(p = skip_name(p, header, plen, 10)))
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++ if (!extract_name(header, plen, &p, daemon->workspacename, 1, 10))
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+ return 0;
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+-
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++
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+ GETSHORT(type, p);
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+ GETSHORT(class, p);
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+ p += 4; /* TTL */
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+@@ -1866,7 +1893,69 @@ static int prove_non_existence(struct dn
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+ if (!expand_workspace(&nsecset, &nsecset_sz, nsecs_found))
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+ return 0;
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+
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+- nsecset[nsecs_found++] = pstart;
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++ if (type == T_NSEC)
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++ {
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++ /* If we're looking for NSECs, find the corresponding SIGs, to
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++ extract the labels value, which we need in case the NSECs
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++ are the result of wildcard expansion.
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++ Note that the NSEC may not have been validated yet
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++ so if there are multiple SIGs, make sure the label value
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++ is the same in all, to avoid be duped by a rogue one.
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++ If there are no SIGs, that's an error */
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++ unsigned char *p1 = auth_start;
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++ int res, j, rdlen1, type1, class1;
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++
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++ if (!expand_workspace(&rrsig_labels, &rrsig_labels_sz, nsecs_found))
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++ return 0;
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++
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++ rrsig_labels[nsecs_found] = NULL;
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++
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++ for (j = ntohs(header->nscount); j != 0; j--)
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++ {
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++ if (!(res = extract_name(header, plen, &p1, daemon->workspacename, 0, 10)))
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++ return 0;
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++
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++ GETSHORT(type1, p1);
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++ GETSHORT(class1, p1);
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++ p1 += 4; /* TTL */
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++ GETSHORT(rdlen1, p1);
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++
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++ if (!CHECK_LEN(header, p1, plen, rdlen1))
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++ return 0;
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++
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++ if (res == 1 && class1 == qclass && type1 == T_RRSIG)
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++ {
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++ int type_covered;
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++ unsigned char *psav = p1;
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++
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++ if (rdlen < 18)
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++ return 0; /* bad packet */
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++
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++ GETSHORT(type_covered, p1);
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++
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++ if (type_covered == T_NSEC)
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++ {
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++ p1++; /* algo */
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++
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++ /* labels field must be the same in every SIG we find. */
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++ if (!rrsig_labels[nsecs_found])
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++ rrsig_labels[nsecs_found] = p1;
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++ else if (*rrsig_labels[nsecs_found] != *p1) /* algo */
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++ return 0;
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++ }
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++ p1 = psav;
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++ }
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++
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++ if (!ADD_RDLEN(header, p1, plen, rdlen1))
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++ return 0;
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++ }
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++
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++ /* Must have found at least one sig. */
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++ if (!rrsig_labels[nsecs_found])
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++ return 0;
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++ }
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++
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++ nsecset[nsecs_found++] = pstart;
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+ }
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+
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+ if (!ADD_RDLEN(header, p, plen, rdlen))
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+@@ -1874,7 +1963,7 @@ static int prove_non_existence(struct dn
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+ }
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+
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+ if (type_found == T_NSEC)
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+- return prove_non_existence_nsec(header, plen, nsecset, nsecs_found, daemon->workspacename, keyname, name, qtype, nons);
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++ return prove_non_existence_nsec(header, plen, nsecset, rrsig_labels, nsecs_found, daemon->workspacename, keyname, name, qtype, nons);
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+ else if (type_found == T_NSEC3)
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+ return prove_non_existence_nsec3(header, plen, nsecset, nsecs_found, daemon->workspacename, keyname, name, qtype, wildname, nons);
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+ else
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