From: Mark Andrews <marka@isc.org>
Date: Tue, 12 Mar 2024 23:15:03 +0000 (+1100)
Subject: Only call memmove if the rdata length is non zero
X-Git-Tag: v9.18.26~29^2
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=3fadd9efec6d0d5b447f26142eef1b2fd9c1bb25;p=thirdparty%2Fbind9.git

Only call memmove if the rdata length is non zero

This avoids undefined behaviour on zero length rdata where the
data pointer is NULL.

(cherry picked from commit 228cc557fe4ca29e34eccb3a1846d7f754879aed)
---

diff --git a/lib/dns/rdataslab.c b/lib/dns/rdataslab.c
index 24fdaa83a19..2b4cc4bed3f 100644
--- a/lib/dns/rdataslab.c
+++ b/lib/dns/rdataslab.c
@@ -320,7 +320,9 @@ dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
 					    ? DNS_RDATASLAB_OFFLINE
 					    : 0;
 		}
-		memmove(rawbuf, x[i].rdata.data, x[i].rdata.length);
+		if (x[i].rdata.length != 0) {
+			memmove(rawbuf, x[i].rdata.data, x[i].rdata.length);
+		}
 		rawbuf += x[i].rdata.length;
 	}