size_t a bunch of bn words bits. Also replace a pointless call to bn_mul_words with a memset. Change-Id: Ief30ddab0e84864561b73fe2776bd0477931cf7f Reviewed-on: https://boringssl-review.googlesource.com/23066 Reviewed-by: Adam Langley <agl@google.com>

diff --git a/crypto/fipsmodule/bn/asm/x86_64-gcc.c b/crypto/fipsmodule/bn/asm/x86_64-gcc.c
index bcf12eb..d8434f7 100644
--- a/crypto/fipsmodule/bn/asm/x86_64-gcc.c
+++ b/crypto/fipsmodule/bn/asm/x86_64-gcc.c

@@ -93,11 +93,11 @@
 #undef sqr
 #define sqr(r0, r1, a) __asm__("mulq %2" : "=a"(r0), "=d"(r1) : "a"(a) : "cc");
 
-BN_ULONG bn_mul_add_words(BN_ULONG *rp, const BN_ULONG *ap, int num,
+BN_ULONG bn_mul_add_words(BN_ULONG *rp, const BN_ULONG *ap, size_t num,
                           BN_ULONG w) {
   BN_ULONG c1 = 0;
 
-  if (num <= 0) {
+  if (num == 0) {
     return (c1);
   }
 
@@ -126,10 +126,11 @@
   return c1;
 }
 
-BN_ULONG bn_mul_words(BN_ULONG *rp, const BN_ULONG *ap, int num, BN_ULONG w) {
+BN_ULONG bn_mul_words(BN_ULONG *rp, const BN_ULONG *ap, size_t num,
+                      BN_ULONG w) {
   BN_ULONG c1 = 0;
 
-  if (num <= 0) {
+  if (num == 0) {
     return c1;
   }
 
@@ -156,8 +157,8 @@
   return c1;
 }
 
-void bn_sqr_words(BN_ULONG *r, const BN_ULONG *a, int n) {
-  if (n <= 0) {
+void bn_sqr_words(BN_ULONG *r, const BN_ULONG *a, size_t n) {
+  if (n == 0) {
     return;
   }
 
@@ -184,11 +185,11 @@
 }
 
 BN_ULONG bn_add_words(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp,
-                      int n) {
+                      size_t n) {
   BN_ULONG ret;
   size_t i = 0;
 
-  if (n <= 0) {
+  if (n == 0) {
     return 0;
   }
 
@@ -211,11 +212,11 @@
 }
 
 BN_ULONG bn_sub_words(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp,
-                      int n) {
+                      size_t n) {
   BN_ULONG ret;
   size_t i = 0;
 
-  if (n <= 0) {
+  if (n == 0) {
     return 0;
   }
 

diff --git a/crypto/fipsmodule/bn/generic.c b/crypto/fipsmodule/bn/generic.c
index 44e0f2c..e81eec3 100644
--- a/crypto/fipsmodule/bn/generic.c
+++ b/crypto/fipsmodule/bn/generic.c

@@ -124,12 +124,11 @@
 
 #endif  // !BN_ULLONG
 
-BN_ULONG bn_mul_add_words(BN_ULONG *rp, const BN_ULONG *ap, int num,
+BN_ULONG bn_mul_add_words(BN_ULONG *rp, const BN_ULONG *ap, size_t num,
                           BN_ULONG w) {
   BN_ULONG c1 = 0;
 
-  assert(num >= 0);
-  if (num <= 0) {
+  if (num == 0) {
     return c1;
   }
 
@@ -153,11 +152,11 @@
   return c1;
 }
 
-BN_ULONG bn_mul_words(BN_ULONG *rp, const BN_ULONG *ap, int num, BN_ULONG w) {
+BN_ULONG bn_mul_words(BN_ULONG *rp, const BN_ULONG *ap, size_t num,
+                      BN_ULONG w) {
   BN_ULONG c1 = 0;
 
-  assert(num >= 0);
-  if (num <= 0) {
+  if (num == 0) {
     return c1;
   }
 
@@ -179,9 +178,8 @@
   return c1;
 }
 
-void bn_sqr_words(BN_ULONG *r, const BN_ULONG *a, int n) {
-  assert(n >= 0);
-  if (n <= 0) {
+void bn_sqr_words(BN_ULONG *r, const BN_ULONG *a, size_t n) {
+  if (n == 0) {
     return;
   }
 
@@ -204,11 +202,10 @@
 
 #ifdef BN_ULLONG
 BN_ULONG bn_add_words(BN_ULONG *r, const BN_ULONG *a, const BN_ULONG *b,
-                      int n) {
+                      size_t n) {
   BN_ULLONG ll = 0;
 
-  assert(n >= 0);
-  if (n <= 0) {
+  if (n == 0) {
     return 0;
   }
 
@@ -245,11 +242,10 @@
 #else  // !BN_ULLONG
 
 BN_ULONG bn_add_words(BN_ULONG *r, const BN_ULONG *a, const BN_ULONG *b,
-                      int n) {
+                      size_t n) {
   BN_ULONG c, l, t;
 
-  assert(n >= 0);
-  if (n <= 0) {
+  if (n == 0) {
     return (BN_ULONG)0;
   }
 
@@ -302,12 +298,11 @@
 #endif  // !BN_ULLONG
 
 BN_ULONG bn_sub_words(BN_ULONG *r, const BN_ULONG *a, const BN_ULONG *b,
-                      int n) {
+                      size_t n) {
   BN_ULONG t1, t2;
   int c = 0;
 
-  assert(n >= 0);
-  if (n <= 0) {
+  if (n == 0) {
     return (BN_ULONG)0;
   }
 

diff --git a/crypto/fipsmodule/bn/internal.h b/crypto/fipsmodule/bn/internal.h
index 57cf755..b5ddd7e 100644
--- a/crypto/fipsmodule/bn/internal.h
+++ b/crypto/fipsmodule/bn/internal.h

@@ -214,34 +214,34 @@
 // the result in |rp|. |ap| and |rp| must both be |num| words long. It returns
 // the carry word of the operation. |ap| and |rp| may be equal but otherwise may
 // not alias.
-BN_ULONG bn_mul_add_words(BN_ULONG *rp, const BN_ULONG *ap, int num,
+BN_ULONG bn_mul_add_words(BN_ULONG *rp, const BN_ULONG *ap, size_t num,
                           BN_ULONG w);
 
 // bn_mul_words multiples |ap| by |w| and places the result in |rp|. |ap| and
 // |rp| must both be |num| words long. It returns the carry word of the
 // operation. |ap| and |rp| may be equal but otherwise may not alias.
-BN_ULONG bn_mul_words(BN_ULONG *rp, const BN_ULONG *ap, int num, BN_ULONG w);
+BN_ULONG bn_mul_words(BN_ULONG *rp, const BN_ULONG *ap, size_t num, BN_ULONG w);
 
 // bn_sqr_words sets |rp[2*i]| and |rp[2*i+1]| to |ap[i]|'s square, for all |i|
 // up to |num|. |ap| is an array of |num| words and |rp| an array of |2*num|
 // words. |ap| and |rp| may not alias.
 //
 // This gives the contribution of the |ap[i]*ap[i]| terms when squaring |ap|.
-void bn_sqr_words(BN_ULONG *rp, const BN_ULONG *ap, int num);
+void bn_sqr_words(BN_ULONG *rp, const BN_ULONG *ap, size_t num);
 
 // bn_add_words adds |ap| to |bp| and places the result in |rp|, each of which
 // are |num| words long. It returns the carry bit, which is one if the operation
 // overflowed and zero otherwise. Any pair of |ap|, |bp|, and |rp| may be equal
 // to each other but otherwise may not alias.
 BN_ULONG bn_add_words(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp,
-                      int num);
+                      size_t num);
 
 // bn_sub_words subtracts |bp| from |ap| and places the result in |rp|. It
 // returns the borrow bit, which is one if the computation underflowed and zero
 // otherwise. Any pair of |ap|, |bp|, and |rp| may be equal to each other but
 // otherwise may not alias.
 BN_ULONG bn_sub_words(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp,
-                      int num);
+                      size_t num);
 
 // bn_mul_comba4 sets |r| to the product of |a| and |b|.
 void bn_mul_comba4(BN_ULONG r[8], BN_ULONG a[4], BN_ULONG b[4]);

diff --git a/crypto/fipsmodule/bn/mul.c b/crypto/fipsmodule/bn/mul.c
index 65f3c2b..800a0bb 100644
--- a/crypto/fipsmodule/bn/mul.c
+++ b/crypto/fipsmodule/bn/mul.c

@@ -60,49 +60,44 @@
 #include <string.h>
 
 #include "internal.h"
+#include "../../internal.h"
 
 
 #define BN_MUL_RECURSIVE_SIZE_NORMAL 16
 #define BN_SQR_RECURSIVE_SIZE_NORMAL BN_MUL_RECURSIVE_SIZE_NORMAL
 
 
-static void bn_mul_normal(BN_ULONG *r, BN_ULONG *a, int na, BN_ULONG *b,
-                          int nb) {
-  BN_ULONG *rr;
-
+static void bn_mul_normal(BN_ULONG *r, BN_ULONG *a, size_t na, BN_ULONG *b,
+                          size_t nb) {
   if (na < nb) {
-    int itmp;
-    BN_ULONG *ltmp;
-
-    itmp = na;
+    size_t itmp = na;
     na = nb;
     nb = itmp;
-    ltmp = a;
+    BN_ULONG *ltmp = a;
     a = b;
     b = ltmp;
   }
-  rr = &(r[na]);
-  if (nb <= 0) {
-    (void)bn_mul_words(r, a, na, 0);
+  BN_ULONG *rr = &(r[na]);
+  if (nb == 0) {
+    OPENSSL_memset(r, 0, na * sizeof(BN_ULONG));
     return;
-  } else {
-    rr[0] = bn_mul_words(r, a, na, b[0]);
   }
+  rr[0] = bn_mul_words(r, a, na, b[0]);
 
   for (;;) {
-    if (--nb <= 0) {
+    if (--nb == 0) {
       return;
     }
     rr[1] = bn_mul_add_words(&(r[1]), a, na, b[1]);
-    if (--nb <= 0) {
+    if (--nb == 0) {
       return;
     }
     rr[2] = bn_mul_add_words(&(r[2]), a, na, b[2]);
-    if (--nb <= 0) {
+    if (--nb == 0) {
       return;
     }
     rr[3] = bn_mul_add_words(&(r[3]), a, na, b[3]);
-    if (--nb <= 0) {
+    if (--nb == 0) {
       return;
     }
     rr[4] = bn_mul_add_words(&(r[4]), a, na, b[4]);
@@ -659,27 +654,30 @@
 }
 
 // tmp must have 2*n words
-static void bn_sqr_normal(BN_ULONG *r, const BN_ULONG *a, int n,
+static void bn_sqr_normal(BN_ULONG *r, const BN_ULONG *a, size_t n,
                           BN_ULONG *tmp) {
-  int max = n * 2;
+  if (n == 0) {
+    return;
+  }
+
+  size_t max = n * 2;
   const BN_ULONG *ap = a;
   BN_ULONG *rp = r;
   rp[0] = rp[max - 1] = 0;
   rp++;
-  int j = n;
 
   // Compute the contribution of a[i] * a[j] for all i < j.
-  if (--j > 0) {
+  if (n > 1) {
     ap++;
-    rp[j] = bn_mul_words(rp, ap, j, ap[-1]);
+    rp[n - 1] = bn_mul_words(rp, ap, n - 1, ap[-1]);
     rp += 2;
   }
-
-  for (int i = n - 2; i > 0; i--) {
-    j--;
-    ap++;
-    rp[j] = bn_mul_add_words(rp, ap, j, ap[-1]);
-    rp += 2;
+  if (n > 2) {
+    for (size_t i = n - 2; i > 0; i--) {
+      ap++;
+      rp[i] = bn_mul_add_words(rp, ap, i, ap[-1]);
+      rp += 2;
+    }
   }
 
   // The final result fits in |max| words, so none of the following operations