Commit 39df5152 authored by Billy Brumley's avatar Billy Brumley Committed by Matt Caswell
Browse files

Remove superfluous NULL checks. Add Andy's BN_FLG comment. 



Reviewed-by: default avatarAndy Polyakov <appro@openssl.org>
Reviewed-by: default avatarMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6009)
parent 736b31e5

crypto/bn/bn_lib.c

+20 −5
Original line number Diff line number Diff line
@@ -743,12 +743,27 @@ void BN_consttime_swap(BN_ULONG condition, BIGNUM *a, BIGNUM *b, int nwords) 
    a->neg ^= t;

    b->neg ^= t;



    /*

     * cannot just arbitrarily swap flags.

     * The way a->d is allocated etc.

     * BN_FLG_MALLOCED, BN_FLG_STATIC_DATA, ...

    /*-

     * Idea behind BN_FLG_STATIC_DATA is actually to

     * indicate that data may not be written to.

     * Intention is actually to treat it as it's

     * read-only data, and some (if not most) of it does

     * reside in read-only segment. In other words

     * observation of BN_FLG_STATIC_DATA in

     * BN_consttime_swap should be treated as fatal

     * condition. It would either cause SEGV or

     * effectively cause data corruption.

     * BN_FLG_MALLOCED refers to BN structure itself,

     * and hence must be preserved. Remaining flags are

     * BN_FLG_CONSTIME and BN_FLG_SECURE. Latter must be

     * preserved, because it determines how x->d was

     * allocated and hence how to free it. This leaves

     * BN_FLG_CONSTTIME that one can do something about.

     * To summarize it's sufficient to mask and swap

     * BN_FLG_CONSTTIME alone. BN_FLG_STATIC_DATA should

     * be treated as fatal.

     */

    t = (a->flags ^ b->flags) & condition & BN_FLG_CONSTTIME;

    t = ((a->flags ^ b->flags) & BN_FLG_CONSTTIME) & condition;

    a->flags ^= t;

    b->flags ^= t;

crypto/ec/ec_mult.c

+0 −5
Original line number Diff line number Diff line
@@ -142,9 +142,6 @@ static int ec_mul_consttime(const EC_GROUP *group, EC_POINT *r, 
    if (ctx == NULL && (ctx = new_ctx = BN_CTX_secure_new()) == NULL)

        goto err;



    if ((group->order == NULL) || (group->field == NULL))

        goto err;



    order_bits = BN_num_bits(group->order);



    s = EC_POINT_new(group);
@@ -152,8 +149,6 @@ static int ec_mul_consttime(const EC_GROUP *group, EC_POINT *r, 
        goto err;



    if (point == NULL) {

        if (group->generator == NULL)

            goto err;

        if (!EC_POINT_copy(s, group->generator))

            goto err;

    } else {