use proper flexible arrays in rrl

The single-element array hack can trip newer sanitizers or fortification
levels.

diff --git a/lib/dns/include/dns/rrl.h b/lib/dns/include/dns/rrl.h
index aef47a7345e0c3c74f3b3eccb57e3525950a6365..6c5be512fdce735011260dbd8ea55f6670498478 100644 (file)
--- a/lib/dns/include/dns/rrl.h
+++ b/lib/dns/include/dns/rrl.h
@@ -19,6 +19,9 @@
 
 #include <inttypes.h>
 #include <stdbool.h>
+#include <stdint.h>
+
+#include <isc/attributes.h>
 
 #include <dns/fixedname.h>
 #include <dns/rdata.h>
@@ -157,7 +160,7 @@ struct dns_rrl_hash {
        isc_stdtime_t check_time;
        unsigned int  gen : DNS_RRL_HASH_GEN_BITS;
        int           length;
-       dns_rrl_bin_t bins[1];
+       dns_rrl_bin_t bins[] ISC_ATTR_COUNTED_BY(length);
 };
 
 /*
@@ -166,8 +169,8 @@ struct dns_rrl_hash {
 typedef struct dns_rrl_block dns_rrl_block_t;
 struct dns_rrl_block {
        ISC_LINK(dns_rrl_block_t) link;
-       int             size;
-       dns_rrl_entry_t entries[1];
+       uint32_t        count;
+       dns_rrl_entry_t entries[] ISC_ATTR_COUNTED_BY(count);
 };
 
 /*

diff --git a/lib/dns/rrl.c b/lib/dns/rrl.c
index dc91711c0c348d76d2457eee2f9e51109bb75c01..c936bc724d4bb4d593e78a1beb9ba9ee68177a1f 100644 (file)
--- a/lib/dns/rrl.c
+++ b/lib/dns/rrl.c
@@ -205,7 +205,6 @@ set_age(dns_rrl_t *rrl, dns_rrl_entry_t *e, isc_stdtime_t now) {
 
 static isc_result_t
 expand_entries(dns_rrl_t *rrl, int newsize) {
-       unsigned int bsize;
        dns_rrl_block_t *b;
        dns_rrl_entry_t *e;
        double rate;
@@ -237,10 +236,11 @@ expand_entries(dns_rrl_t *rrl, int newsize) {
                              rrl->hash->length, rate);
        }
 
-       bsize = sizeof(dns_rrl_block_t) +
-               ISC_CHECKED_MUL((newsize - 1), sizeof(dns_rrl_entry_t));
-       b = isc_mem_cget(rrl->mctx, 1, bsize);
-       b->size = bsize;
+       b = isc_mem_cget(rrl->mctx, 1, STRUCT_FLEX_SIZE(b, entries, newsize));
+       *b = (dns_rrl_block_t){
+               .link = ISC_LINK_INITIALIZER,
+               .count = newsize,
+       };
 
        e = b->entries;
        for (i = 0; i < newsize; ++i, ++e) {
@@ -274,16 +274,14 @@ free_old_hash(dns_rrl_t *rrl) {
        }
 
        isc_mem_put(rrl->mctx, old_hash,
-                   sizeof(*old_hash) +
-                           ISC_CHECKED_MUL((old_hash->length - 1),
-                                           sizeof(old_hash->bins[0])));
+                   STRUCT_FLEX_SIZE(old_hash, bins, old_hash->length));
        rrl->old_hash = NULL;
 }
 
 static isc_result_t
 expand_rrl_hash(dns_rrl_t *rrl, isc_stdtime_t now) {
        dns_rrl_hash_t *hash;
-       int old_bins, new_bins, hsize;
+       int old_bins, new_bins;
        double rate;
 
        if (rrl->old_hash != NULL) {
@@ -301,12 +299,13 @@ expand_rrl_hash(dns_rrl_t *rrl, isc_stdtime_t now) {
        }
        new_bins = hash_divisor(new_bins);
 
-       hsize = sizeof(dns_rrl_hash_t) +
-               ISC_CHECKED_MUL((new_bins - 1), sizeof(hash->bins[0]));
-       hash = isc_mem_cget(rrl->mctx, 1, hsize);
-       hash->length = new_bins;
        rrl->hash_gen ^= 1;
-       hash->gen = rrl->hash_gen;
+       hash = isc_mem_cget(rrl->mctx, 1,
+                           STRUCT_FLEX_SIZE(hash, bins, new_bins));
+       *hash = (dns_rrl_hash_t){
+               .length = new_bins,
+               .gen = rrl->hash_gen,
+       };
 
        if (isc_log_wouldlog(DNS_RRL_LOG_DROP) && old_bins != 0) {
                rate = rrl->probes;
@@ -1283,21 +1282,18 @@ dns_rrl_view_destroy(dns_view_t *view) {
 
        ISC_LIST_FOREACH (rrl->blocks, b, link) {
                ISC_LIST_UNLINK(rrl->blocks, b, link);
-               isc_mem_put(rrl->mctx, b, b->size);
+               isc_mem_put(rrl->mctx, b,
+                           STRUCT_FLEX_SIZE(b, entries, b->count));
        }
 
        h = rrl->hash;
        if (h != NULL) {
-               isc_mem_put(rrl->mctx, h,
-                           sizeof(*h) + ISC_CHECKED_MUL((h->length - 1),
-                                                        sizeof(h->bins[0])));
+               isc_mem_put(rrl->mctx, h, STRUCT_FLEX_SIZE(h, bins, h->length));
        }
 
        h = rrl->old_hash;
        if (h != NULL) {
-               isc_mem_put(rrl->mctx, h,
-                           sizeof(*h) + ISC_CHECKED_MUL((h->length - 1),
-                                                        sizeof(h->bins[0])));
+               isc_mem_put(rrl->mctx, h, STRUCT_FLEX_SIZE(h, bins, h->length));
        }
 
        isc_mem_putanddetach(&rrl->mctx, rrl, sizeof(*rrl));