resolve conflicts

1 files changed, 41 insertions, 35 deletions

diff --git a/src/lib/libcrypto/bn/bn_sqrt.c b/src/lib/libcrypto/bn/bn_sqrt.c
index e2a1105dc8..6beaf9e5e5 100644
--- a/src/lib/libcrypto/bn/bn_sqrt.c
+++ b/src/lib/libcrypto/bn/bn_sqrt.c
@@ -1,4 +1,4 @@
-/* crypto/bn/bn_mod.c */
+/* crypto/bn/bn_sqrt.c */
 /* Written by Lenka Fibikova <fibikova@exp-math.uni-essen.de>
  * and Bodo Moeller for the OpenSSL project. */
 /* ====================================================================
@@ -65,14 +65,12 @@ BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
  * using the Tonelli/Shanks algorithm (cf. Henri Cohen, "A Course
  * in Algebraic Computational Number Theory", algorithm 1.5.1).
  * 'p' must be prime!
- * If 'a' is not a square, this is not necessarily detected by
- * the algorithms; a bogus result must be expected in this case.
  */
         {
         BIGNUM *ret = in;
         int err = 1;
         int r;
-        BIGNUM *b, *q, *t, *x, *y;
+        BIGNUM *A, *b, *q, *t, *x, *y;
         int e, i, j;
         
         if (!BN_is_odd(p) || BN_abs_is_word(p, 1))
@@ -85,9 +83,11 @@ BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
                                 goto end;
                         if (!BN_set_word(ret, BN_is_bit_set(a, 0)))
                                 {
-                                BN_free(ret);
+                                if (ret != in)
+                                        BN_free(ret);
                                 return NULL;
                                 }
+                        bn_check_top(ret);
                         return ret;
                         }
 
@@ -103,23 +103,16 @@ BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
                         goto end;
                 if (!BN_set_word(ret, BN_is_one(a)))
                         {
-                        BN_free(ret);
+                        if (ret != in)
+                                BN_free(ret);
                         return NULL;
                         }
+                bn_check_top(ret);
                 return ret;
                 }
 
-#if 0 /* if BN_mod_sqrt is used with correct input, this just wastes time */
-        r = BN_kronecker(a, p, ctx);
-        if (r < -1) return NULL;
-        if (r == -1)
-                {
-                BNerr(BN_F_BN_MOD_SQRT, BN_R_NOT_A_SQUARE);
-                return(NULL);
-                }
-#endif
-
         BN_CTX_start(ctx);
+        A = BN_CTX_get(ctx);
         b = BN_CTX_get(ctx);
         q = BN_CTX_get(ctx);
         t = BN_CTX_get(ctx);
@@ -131,6 +124,9 @@ BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
                 ret = BN_new();
         if (ret == NULL) goto end;
 
+        /* A = a mod p */
+        if (!BN_nnmod(A, a, p, ctx)) goto end;
+
         /* now write  |p| - 1  as  2^e*q  where  q  is odd */
         e = 1;
         while (!BN_is_bit_set(p, e))
@@ -149,9 +145,9 @@ BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
                 if (!BN_rshift(q, p, 2)) goto end;
                 q->neg = 0;
                 if (!BN_add_word(q, 1)) goto end;
-                if (!BN_mod_exp(ret, a, q, p, ctx)) goto end;
+                if (!BN_mod_exp(ret, A, q, p, ctx)) goto end;
                 err = 0;
-                goto end;
+                goto vrfy;
                 }
         
         if (e == 2)
@@ -182,15 +178,8 @@ BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
                  * November 1992.)
                  */
 
-                /* make sure that  a  is reduced modulo p */
-                if (a->neg || BN_ucmp(a, p) >= 0)
-                        {
-                        if (!BN_nnmod(x, a, p, ctx)) goto end;
-                        a = x; /* use x as temporary variable */
-                        }
-
                 /* t := 2*a */
-                if (!BN_mod_lshift1_quick(t, a, p)) goto end;
+                if (!BN_mod_lshift1_quick(t, A, p)) goto end;
 
                 /* b := (2*a)^((|p|-5)/8) */
                 if (!BN_rshift(q, p, 3)) goto end;
@@ -205,12 +194,12 @@ BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
                 if (!BN_sub_word(t, 1)) goto end;
 
                 /* x = a*b*t */
-                if (!BN_mod_mul(x, a, b, p, ctx)) goto end;
+                if (!BN_mod_mul(x, A, b, p, ctx)) goto end;
                 if (!BN_mod_mul(x, x, t, p, ctx)) goto end;
 
                 if (!BN_copy(ret, x)) goto end;
                 err = 0;
-                goto end;
+                goto vrfy;
                 }
         
         /* e > 2, so we really have to use the Tonelli/Shanks algorithm.
@@ -297,11 +286,11 @@ BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
         /* x := a^((q-1)/2) */
         if (BN_is_zero(t)) /* special case: p = 2^e + 1 */
                 {
-                if (!BN_nnmod(t, a, p, ctx)) goto end;
+                if (!BN_nnmod(t, A, p, ctx)) goto end;
                 if (BN_is_zero(t))
                         {
                         /* special case: a == 0  (mod p) */
-                        if (!BN_zero(ret)) goto end;
+                        BN_zero(ret);
                         err = 0;
                         goto end;
                         }
@@ -310,11 +299,11 @@ BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
                 }
         else
                 {
-                if (!BN_mod_exp(x, a, t, p, ctx)) goto end;
+                if (!BN_mod_exp(x, A, t, p, ctx)) goto end;
                 if (BN_is_zero(x))
                         {
                         /* special case: a == 0  (mod p) */
-                        if (!BN_zero(ret)) goto end;
+                        BN_zero(ret);
                         err = 0;
                         goto end;
                         }
@@ -322,10 +311,10 @@ BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
 
         /* b := a*x^2  (= a^q) */
         if (!BN_mod_sqr(b, x, p, ctx)) goto end;
-        if (!BN_mod_mul(b, b, a, p, ctx)) goto end;
+        if (!BN_mod_mul(b, b, A, p, ctx)) goto end;
         
         /* x := a*x    (= a^((q+1)/2)) */
-        if (!BN_mod_mul(x, x, a, p, ctx)) goto end;
+        if (!BN_mod_mul(x, x, A, p, ctx)) goto end;
 
         while (1)
                 {
@@ -342,7 +331,7 @@ BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
                         {
                         if (!BN_copy(ret, x)) goto end;
                         err = 0;
-                        goto end;
+                        goto vrfy;
                         }
 
 
@@ -373,6 +362,22 @@ BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
                 e = i;
                 }
 
+ vrfy:
+        if (!err)
+                {
+                /* verify the result -- the input might have been not a square
+                 * (test added in 0.9.8) */
+                
+                if (!BN_mod_sqr(x, ret, p, ctx))
+                        err = 1;
+                
+                if (!err && 0 != BN_cmp(x, A))
+                        {
+                        BNerr(BN_F_BN_MOD_SQRT, BN_R_NOT_A_SQUARE);
+                        err = 1;
+                        }
+                }
+
  end:
         if (err)
                 {
@@ -383,5 +388,6 @@ BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
                 ret = NULL;
                 }
         BN_CTX_end(ctx);
+        bn_check_top(ret);
         return ret;
         }