diff --git a/lib/rsa/rsa-sign.c b/lib/rsa/rsa-sign.c
index 40ca1e1f573..1f0d81bd7a3 100644
--- a/lib/rsa/rsa-sign.c
+++ b/lib/rsa/rsa-sign.c
@@ -708,7 +708,7 @@ static int fdt_add_bignum(void *blob, int noffset, const char *prop_name,
 		return -ENOMEM;
 	}
 	ctx = BN_CTX_new();
-	if (!tmp) {
+	if (!ctx) {
 		fprintf(stderr, "Out of memory (bignum context)\n");
 		return -ENOMEM;
 	}