diff options
| author | Geoff Thorpe <geoff@openssl.org> | 2003-11-25 20:39:19 +0000 |
|---|---|---|
| committer | Geoff Thorpe <geoff@openssl.org> | 2003-11-25 20:39:19 +0000 |
| commit | 6defae04f3c44087d9129994fa88b4f9271b153f (patch) | |
| tree | ef530add1d1c35f639558ea455dbf4b66d8b104a /crypto/bn/bn_word.c | |
| parent | e1064adfd3b4d014c7de36e4390eaa5b129f4bfc (diff) | |
Fix some handling in bn_word. This also resolves the issues observed in
ticket 697 (though uses a different solution than the proposed one). This
problem was initially raised by Otto Moerbeek.
PR: 697
Submitted by: Nils Larsch
Reviewed by: Geoff Thorpe
Diffstat (limited to 'crypto/bn/bn_word.c')
| -rw-r--r-- | crypto/bn/bn_word.c | 25 |
1 files changed, 19 insertions, 6 deletions
diff --git a/crypto/bn/bn_word.c b/crypto/bn/bn_word.c index 560a499692..a241150157 100644 --- a/crypto/bn/bn_word.c +++ b/crypto/bn/bn_word.c @@ -85,12 +85,17 @@ BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w) BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w) { - BN_ULONG ret; + BN_ULONG ret = 0; int i; - if (a->top == 0) return(0); - ret=0; - w&=BN_MASK2; + w &= BN_MASK2; + + if (!w) + /* actually this an error (division by zero) */ + return 0; + if (a->top == 0) + return 0; + for (i=a->top-1; i>=0; i--) { BN_ULONG l,d; @@ -111,6 +116,11 @@ int BN_add_word(BIGNUM *a, BN_ULONG w) BN_ULONG l; int i; + w &= BN_MASK2; + + if (!w) + return 1; + if (a->neg) { a->neg=0; @@ -119,7 +129,6 @@ int BN_add_word(BIGNUM *a, BN_ULONG w) a->neg=!(a->neg); return(i); } - w&=BN_MASK2; if (bn_wexpand(a,a->top+1) == NULL) return(0); i=0; for (;;) @@ -145,6 +154,11 @@ int BN_sub_word(BIGNUM *a, BN_ULONG w) { int i; + w &= BN_MASK2; + + if (!w) + return 1; + if (BN_is_zero(a) || a->neg) { a->neg=0; @@ -153,7 +167,6 @@ int BN_sub_word(BIGNUM *a, BN_ULONG w) return(i); } - w&=BN_MASK2; if ((a->top == 1) && (a->d[0] < w)) { a->d[0]=w-a->d[0]; |