Lookups: fix dbmnz crash on zero-length datum. Bug 3079

[exim.git] / src / src / exim_dbutil.c

diff --git a/src/src/exim_dbutil.c b/src/src/exim_dbutil.c
index 3824309b52b3605543c2bb7aad4ce2e1e17658d6..4d213773bf9203ac9b8554bbb3e8414193a37c8d 100644 (file)
--- a/src/src/exim_dbutil.c
+++ b/src/src/exim_dbutil.c
@@ -2,9 +2,10 @@
 *     Exim - an Internet mail transport agent    *
 *************************************************/
 
-/* Copyright (c) The Exim Maintainers 2020 - 2022 */
+/* Copyright (c) The Exim Maintainers 2020 - 2023 */
 /* Copyright (c) University of Cambridge 1995 - 2018 */
 /* See the file NOTICE for conditions of use and distribution. */
+/* SPDX-License-Identifier: GPL-2.0-or-later */
 
 
 /* This single source file is used to compile three utility programs for
@@ -60,6 +61,9 @@ uschar *
 readconf_printtime(int t)
 { return NULL; }
 gstring *
+string_catn(gstring * g, const uschar * s, int count)
+{ return NULL; }
+gstring *
 string_vformat_trc(gstring * g, const uschar * func, unsigned line,
   unsigned size_limit, unsigned flags, const char *format, va_list ap)
 { return NULL; }
@@ -403,12 +407,13 @@ Returns: a pointer to the retrieved record, or
 */
 
 void *
-dbfn_read_with_length(open_db *dbblock, const uschar *key, int *length)
+dbfn_read_with_length(open_db * dbblock, const uschar * key, int * length)
 {
-void *yield;
+void * yield;
 EXIM_DATUM key_datum, result_datum;
 int klen = Ustrlen(key) + 1;
 uschar * key_copy = store_get(klen, key);
+unsigned dlen;
 
 memcpy(key_copy, key, klen);
 
@@ -422,9 +427,10 @@ if (!exim_dbget(dbblock->dbptr, &key_datum, &result_datum)) return NULL;
 /* Assume for now that anything stored could have been tainted. Properly
 we should store the taint status along with the data. */
 
-yield = store_get(exim_datum_size_get(&result_datum), GET_TAINTED);
-memcpy(yield, exim_datum_data_get(&result_datum), exim_datum_size_get(&result_datum));
-if (length) *length = exim_datum_size_get(&result_datum);
+dlen = exim_datum_size_get(&result_datum);
+yield = store_get(dlen, GET_TAINTED);
+memcpy(yield, exim_datum_data_get(&result_datum), dlen);
+if (length) *length = dlen;
 
 exim_datum_free(&result_datum);    /* Some DBM libs require freeing */
 return yield;