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| author | Bodo Möller <bodo@openssl.org> | 2000-12-07 22:06:09 +0000 |
|---|---|---|
| committer | Bodo Möller <bodo@openssl.org> | 2000-12-07 22:06:09 +0000 |
| commit | 8dea52fa4270a71535b2677953662499946f02e3 (patch) | |
| tree | 6c419fda8d18eac4d092e595ed5a087d6a89f1d0 /crypto/bn/bn_exp.c | |
| parent | f7356b677b35ad58ea2db85cfd22af83b0267978 (diff) | |
| download | openssl-new-8dea52fa4270a71535b2677953662499946f02e3.tar.gz | |
Fix some things that look like bugs.
One problem that looked like a problem in bn_recp.c at first turned
out to be a BN_mul bug. An example is given in bn_recp.c; finding
the bug responsible for this is left as an exercise.
Diffstat (limited to 'crypto/bn/bn_exp.c')
| -rw-r--r-- | crypto/bn/bn_exp.c | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/crypto/bn/bn_exp.c b/crypto/bn/bn_exp.c index 1739be6864..afdfd580fb 100644 --- a/crypto/bn/bn_exp.c +++ b/crypto/bn/bn_exp.c @@ -246,7 +246,17 @@ int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, if ((aa = BN_CTX_get(ctx)) == NULL) goto err; BN_RECP_CTX_init(&recp); - if (BN_RECP_CTX_set(&recp,m,ctx) <= 0) goto err; + if (m->neg) + { + /* ignore sign of 'm' */ + if (!BN_copy(aa, m)) goto err; + aa->neg = 0; + if (BN_RECP_CTX_set(&recp,aa,ctx) <= 0) goto err; + } + else + { + if (BN_RECP_CTX_set(&recp,m,ctx) <= 0) goto err; + } BN_init(&(val[0])); ts=1; @@ -497,9 +507,13 @@ int BN_mod_exp_mont_word(BIGNUM *rr, BN_ULONG a, const BIGNUM *p, (/* BN_ucmp(r, (m)) < 0 ? 1 :*/ \ (BN_mod(t, r, m, ctx) && (swap_tmp = r, r = t, t = swap_tmp, 1)))) /* BN_MOD_MUL_WORD is only used with 'w' large, - * so the BN_ucmp test is probably more overhead - * than always using BN_mod (which uses BN_copy if - * a similar test returns true). */ + * so the BN_ucmp test is probably more overhead + * than always using BN_mod (which uses BN_copy if + * a similar test returns true). */ + /* We can use BN_mod and do not need BN_nnmod because our + * accumulator is never negative (the result of BN_mod does + * not depend on the sign of the modulus). + */ #define BN_TO_MONTGOMERY_WORD(r, w, mont) \ (BN_set_word(r, (w)) && BN_to_montgomery(r, r, (mont), ctx)) |