diff options
Diffstat (limited to 'crypto/bn/bn_exp.c')
| -rw-r--r-- | crypto/bn/bn_exp.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/crypto/bn/bn_exp.c b/crypto/bn/bn_exp.c index cb6d19229f..b876edbfac 100644 --- a/crypto/bn/bn_exp.c +++ b/crypto/bn/bn_exp.c @@ -242,6 +242,14 @@ int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, wstart = bits - 1; /* The top bit of the window */ wend = 0; /* The bottom bit of the window */ + if (r == p) { + BIGNUM *p_dup = BN_CTX_get(ctx); + + if (p_dup == NULL || BN_copy(p_dup, p) == NULL) + goto err; + p = p_dup; + } + if (!BN_one(r)) goto err; @@ -1317,6 +1325,11 @@ int BN_mod_exp_simple(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, return 0; } + if (r == m) { + ERR_raise(ERR_LIB_BN, ERR_R_PASSED_INVALID_ARGUMENT); + return 0; + } + bits = BN_num_bits(p); if (bits == 0) { /* x**0 mod 1, or x**0 mod -1 is still zero. */ @@ -1361,6 +1374,14 @@ int BN_mod_exp_simple(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, wstart = bits - 1; /* The top bit of the window */ wend = 0; /* The bottom bit of the window */ + if (r == p) { + BIGNUM *p_dup = BN_CTX_get(ctx); + + if (p_dup == NULL || BN_copy(p_dup, p) == NULL) + goto err; + p = p_dup; + } + if (!BN_one(r)) goto err; |