Change to mitigate branch prediction attacks

[openssl.git] / crypto / bn / bn.h

diff --git a/crypto/bn/bn.h b/crypto/bn/bn.h
index 6eb4d999c2f519d4162041aa2aea47a8e791ae6b..d69e37b04def58f99813c401e447c39957a40ca9 100644 (file)
--- a/crypto/bn/bn.h
+++ b/crypto/bn/bn.h
@@ -256,8 +256,18 @@ extern "C" {
 
 #define BN_FLG_MALLOCED                0x01
 #define BN_FLG_STATIC_DATA     0x02
-#define BN_FLG_EXP_CONSTTIME   0x04 /* avoid leaking exponent information through timings
-                                     * (BN_mod_exp_mont() will call BN_mod_exp_mont_consttime) */
+#define BN_FLG_CONSTTIME       0x04 /* avoid leaking exponent information through timing,
+                                      * BN_mod_exp_mont() will call BN_mod_exp_mont_consttime,
+                                      * BN_div() will call BN_div_no_branch,
+                                      * BN_mod_inverse() will call BN_mod_inverse_no_branch.
+                                      */
+
+#ifndef OPENSSL_NO_DEPRECATED
+#define BN_FLG_EXP_CONSTTIME BN_FLG_CONSTTIME /* deprecated name for the flag */
+                                      /* avoid leaking exponent information through timings
+                                      * (BN_mod_exp_mont() will call BN_mod_exp_mont_consttime) */
+#endif
+
 #ifndef OPENSSL_NO_DEPRECATED
 #define BN_FLG_FREE            0x8000  /* used for debuging */
 #endif
@@ -436,6 +446,8 @@ void        BN_set_negative(BIGNUM *b, int n);
 
 int    BN_div(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m, const BIGNUM *d,
        BN_CTX *ctx);
+int    BN_div_no_branch(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m,
+       const BIGNUM *d, BN_CTX *ctx);
 #define BN_mod(rem,m,d,ctx) BN_div(NULL,(rem),(m),(d),(ctx))
 int    BN_nnmod(BIGNUM *r, const BIGNUM *m, const BIGNUM *d, BN_CTX *ctx);
 int    BN_mod_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m, BN_CTX *ctx);
@@ -505,6 +517,8 @@ int BN_gcd(BIGNUM *r,const BIGNUM *a,const BIGNUM *b,BN_CTX *ctx);
 int    BN_kronecker(const BIGNUM *a,const BIGNUM *b,BN_CTX *ctx); /* returns -2 for error */
 BIGNUM *BN_mod_inverse(BIGNUM *ret,
        const BIGNUM *a, const BIGNUM *n,BN_CTX *ctx);
+BIGNUM *BN_mod_inverse_no_branch(BIGNUM *ret,
+       const BIGNUM *A, const BIGNUM *n,BN_CTX *ctx);
 BIGNUM *BN_mod_sqrt(BIGNUM *ret,
        const BIGNUM *a, const BIGNUM *n,BN_CTX *ctx);