Extra Makefile hack for compatibility with OpenBSD 'make'.

[BearSSL] / src / rsa / rsa_i15_pub.c

diff --git a/src/rsa/rsa_i15_pub.c b/src/rsa/rsa_i15_pub.c
index 09f558a..9eab5e8 100644 (file)
--- a/src/rsa/rsa_i15_pub.c
+++ b/src/rsa/rsa_i15_pub.c
@@ -28,7 +28,7 @@
  * As a strict minimum, we need four buffers that can hold a
  * modular integer.
  */
-#define TLEN   (4 * (1 + ((BR_MAX_RSA_SIZE + 14) / 15)))
+#define TLEN   (4 * (2 + ((BR_MAX_RSA_SIZE + 14) / 15)))
 
 /* see bearssl_rsa.h */
 uint32_t
@@ -37,7 +37,7 @@ br_rsa_i15_public(unsigned char *x, size_t xlen,
 {
        const unsigned char *n;
        size_t nlen;
-       uint16_t tmp[TLEN];
+       uint16_t tmp[1 + TLEN];
        uint16_t *m, *a, *t;
        size_t fwlen;
        long z;
@@ -63,15 +63,25 @@ br_rsa_i15_public(unsigned char *x, size_t xlen,
                z -= 15;
                fwlen ++;
        }
+       /*
+        * Round up length to an even number.
+        */
+       fwlen += (fwlen & 1);
 
        /*
         * The modulus gets decoded into m[].
         * The value to exponentiate goes into a[].
         * The temporaries for modular exponentiations are in t[].
+        *
+        * We want the first value word of each integer to be aligned
+        * on a 32-bit boundary.
         */
        m = tmp;
-       a = tmp + fwlen;
-       t = tmp + 2 * fwlen;
+       if (((uintptr_t)m & 2) == 0) {
+               m ++;
+       }
+       a = m + fwlen;
+       t = m + 2 * fwlen;
 
        /*
         * Decode the modulus.