diff --git a/sys/kern/kern_environment.c b/sys/kern/kern_environment.c
--- a/sys/kern/kern_environment.c
+++ b/sys/kern/kern_environment.c
@@ -747,6 +747,33 @@
 	return (cp != NULL);
 }
 
+static int
+quad_multiplier(char suffix, int64_t *mult)
+{
+	int64_t multiplier = 1;
+
+	switch (suffix) {
+	case 't': case 'T':
+		multiplier *= 1024;
+		/* FALLTHROUGH */
+	case 'g': case 'G':
+		multiplier *= 1024;
+		/* FALLTHROUGH */
+	case 'm': case 'M':
+		multiplier *= 1024;
+		/* FALLTHROUGH */
+	case 'k': case 'K':
+		multiplier *= 1024;
+	case '\0':
+		break;
+	default:
+		return (-1);
+	}
+	*mult = multiplier;
+
+	return (0);
+}
+
 /*
  * Return an array of integers at the given type size and signedness.
  */
@@ -754,8 +781,8 @@
 getenv_array(const char *name, void *pdata, int size, int *psize,
     int type_size, bool allow_signed)
 {
-	uint8_t shift;
 	int64_t value;
+	int64_t mult;
 	int64_t old;
 	const char *buf;
 	char *end;
@@ -786,37 +813,9 @@
 			goto error;
 
 		/* check for valid suffix */
-		switch (*end) {
-		case 't':
-		case 'T':
-			shift = 40;
-			end++;
-			break;
-		case 'g':
-		case 'G':
-			shift = 30;
-			end++;
-			break;
-		case 'm':
-		case 'M':
-			shift = 20;
-			end++;
-			break;
-		case 'k':
-		case 'K':
-			shift = 10;
-			end++;
-			break;
-		case ' ':
-		case '\t':
-		case ',':
-		case 0:
-			shift = 0;
-			break;
-		default:
-			/* garbage after numeric value */
+		rc = quad_multiplier(*end, &mult);
+		if (rc != 0)
 			goto error;
-		}
 
 		/* skip till next value, if any */
 		while (*end == '\t' || *end == ',' || *end == ' ')
@@ -827,10 +826,10 @@
 
 		/* apply shift */
 		old = value;
-		value <<= shift;
+		value *= mult;
 
 		/* overflow check */
-		if ((value >> shift) != old)
+		if ((value / mult) != old)
 			goto error;
 
 		/* check for buffer overflow */
@@ -910,7 +909,7 @@
 	quad_t tmp;
 	int rval;
 
-	rval = getenv_quad(name, &tmp);
+	rval = getenv_uquad(name, &tmp);
 	if (rval)
 		*data = (unsigned int) tmp;
 	return (rval);
@@ -940,7 +939,7 @@
 	quad_t tmp;
 	uint64_t rval;
 
-	rval = getenv_quad(name, &tmp);
+	rval = getenv_uquad(name, &tmp);
 	if (rval)
 		*data = (uint64_t) tmp;
 	return (rval);
@@ -970,12 +969,45 @@
 	quad_t tmp;
 	int rval;
 
-	rval = getenv_quad(name, &tmp);
+	rval = getenv_uquad(name, &tmp);
 	if (rval)
 		*data = (unsigned long) tmp;
 	return (rval);
 }
 
+/*
+ * Return a u_quad_t value from an environment variable.
+ */
+int
+getenv_uquad(const char *name, u_quad_t *data)
+{
+	const char	*value;
+	char		suffix, *vtp;
+	u_quad_t	iv;
+	int64_t		mult;
+	int		err;
+
+	value = kenv_acquire(name);
+	if (value == NULL) {
+		goto error;
+	}
+	iv = strtouq(value, &vtp, 0);
+	if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) {
+		goto error;
+	}
+	suffix = vtp[0];
+	kenv_release(value);
+	err = quad_multiplier(suffix, &mult);
+	if (err != 0)
+		return (0);
+	iv *= mult;
+	*data = iv;
+	return (1);
+error:
+	kenv_release(value);
+	return (0);
+}
+
 /*
  * Return a quad_t value from an environment variable.
  */
@@ -985,6 +1017,8 @@
 	const char	*value;
 	char		suffix, *vtp;
 	quad_t		iv;
+	int64_t		mult;
+	int		err;
 
 	value = kenv_acquire(name);
 	if (value == NULL) {
@@ -996,23 +1030,10 @@
 	}
 	suffix = vtp[0];
 	kenv_release(value);
-	switch (suffix) {
-	case 't': case 'T':
-		iv *= 1024;
-		/* FALLTHROUGH */
-	case 'g': case 'G':
-		iv *= 1024;
-		/* FALLTHROUGH */
-	case 'm': case 'M':
-		iv *= 1024;
-		/* FALLTHROUGH */
-	case 'k': case 'K':
-		iv *= 1024;
-	case '\0':
-		break;
-	default:
+	err = quad_multiplier(suffix, &mult);
+	if (err != 0)
 		return (0);
-	}
+	iv *= mult;
 	*data = iv;
 	return (1);
 error:
diff --git a/sys/sys/systm.h b/sys/sys/systm.h
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -417,6 +417,7 @@
 int	getenv_int64(const char *name, int64_t *data);
 int	getenv_uint64(const char *name, uint64_t *data);
 int	getenv_quad(const char *name, quad_t *data);
+int	getenv_uquad(const char *name, u_quad_t *data);
 int	getenv_bool(const char *name, bool *data);
 bool	getenv_is_true(const char *name);
 bool	getenv_is_false(const char *name);