diff --git a/xdiff/xdiffi.c b/xdiff/xdiffi.c
index 758410c11a..53e803e6bc 100644
--- a/xdiff/xdiffi.c
+++ b/xdiff/xdiffi.c
@@ -337,7 +337,7 @@ int xdl_do_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
 	 * One is to store the forward path and one to store the backward path.
 	 */
 	ndiags = xe->xdf1.nreff + xe->xdf2.nreff + 3;
-	if (!(kvd = (long *) xdl_malloc((2 * ndiags + 2) * sizeof(long)))) {
+	if (!XDL_ALLOC_ARRAY(kvd, 2 * ndiags + 2)) {
 
 		xdl_free_env(xe);
 		return -1;
diff --git a/xdiff/xmacros.h b/xdiff/xmacros.h
index ae4636c247..9fd3c5da91 100644
--- a/xdiff/xmacros.h
+++ b/xdiff/xmacros.h
@@ -49,5 +49,10 @@ do { \
 		((unsigned long) __p[2]) << 16 | ((unsigned long) __p[3]) << 24; \
 } while (0)
 
+/* Allocate an array of nr elements, returns NULL on failure */
+#define XDL_ALLOC_ARRAY(p, nr)				\
+	((p) = SIZE_MAX / sizeof(*(p)) >= (size_t)(nr)	\
+		? xdl_malloc((nr) * sizeof(*(p)))	\
+		: NULL)
 
 #endif /* #if !defined(XMACROS_H) */
diff --git a/xdiff/xpatience.c b/xdiff/xpatience.c
index 1a21c6a74b..ce87b9084c 100644
--- a/xdiff/xpatience.c
+++ b/xdiff/xpatience.c
@@ -200,7 +200,7 @@ static int binary_search(struct entry **sequence, int longest,
  */
 static int find_longest_common_sequence(struct hashmap *map, struct entry **res)
 {
-	struct entry **sequence = xdl_malloc(map->nr * sizeof(struct entry *));
+	struct entry **sequence;
 	int longest = 0, i;
 	struct entry *entry;
 
@@ -211,7 +211,7 @@ static int find_longest_common_sequence(struct hashmap *map, struct entry **res)
 	 */
 	int anchor_i = -1;
 
-	if (!sequence)
+	if (!XDL_ALLOC_ARRAY(sequence, map->nr))
 		return -1;
 
 	for (entry = map->first; entry; entry = entry->next) {
diff --git a/xdiff/xprepare.c b/xdiff/xprepare.c
index 105752758f..25866a1667 100644
--- a/xdiff/xprepare.c
+++ b/xdiff/xprepare.c
@@ -86,7 +86,7 @@ static int xdl_init_classifier(xdlclassifier_t *cf, long size, long flags) {
 	memset(cf->rchash, 0, cf->hsize * sizeof(xdlclass_t *));
 
 	cf->alloc = size;
-	if (!(cf->rcrecs = (xdlclass_t **) xdl_malloc(cf->alloc * sizeof(xdlclass_t *)))) {
+	if (!XDL_ALLOC_ARRAY(cf->rcrecs, cf->alloc)) {
 
 		xdl_free(cf->rchash);
 		xdl_cha_free(&cf->ncha);
@@ -178,7 +178,7 @@ static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, long narec, xpparam_
 
 	if (xdl_cha_init(&xdf->rcha, sizeof(xrecord_t), narec / 4 + 1) < 0)
 		goto abort;
-	if (!(recs = (xrecord_t **) xdl_malloc(narec * sizeof(xrecord_t *))))
+	if (!XDL_ALLOC_ARRAY(recs, narec))
 		goto abort;
 
 	hbits = xdl_hashbits((unsigned int) narec);
@@ -215,9 +215,9 @@ static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, long narec, xpparam_
 
 	if ((XDF_DIFF_ALG(xpp->flags) != XDF_PATIENCE_DIFF) &&
 	    (XDF_DIFF_ALG(xpp->flags) != XDF_HISTOGRAM_DIFF)) {
-		if (!(rindex = xdl_malloc((nrec + 1) * sizeof(*rindex))))
+		if (!XDL_ALLOC_ARRAY(rindex, nrec + 1))
 			goto abort;
-		if (!(ha = xdl_malloc((nrec + 1) * sizeof(*ha))))
+		if (!XDL_ALLOC_ARRAY(ha, nrec + 1))
 			goto abort;
 	}