diff options
author | Andy Polyakov <appro@openssl.org> | 2012-11-09 13:58:40 +0000 |
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committer | Dr. Stephen Henson <steve@openssl.org> | 2013-02-05 16:50:36 +0000 |
commit | 1213e6c3c2d7abeeb886d911a3c6c06c5da2e3a4 (patch) | |
tree | 4c6602f770f916af00dbcd427552d0ea6f1ddf04 /crypto/bn | |
parent | 32619893b4a1311a95fb8b3d27afdb6df0246ccc (diff) |
bn_word.c: fix overflow bug in BN_add_word.
(cherry picked from commit 134c00659a1bc67ad35a1e4620e16bc4315e6e37)
Diffstat (limited to 'crypto/bn')
-rw-r--r-- | crypto/bn/bn_word.c | 25 |
1 files changed, 8 insertions, 17 deletions
diff --git a/crypto/bn/bn_word.c b/crypto/bn/bn_word.c index ee7b87c45c..de83a15b99 100644 --- a/crypto/bn/bn_word.c +++ b/crypto/bn/bn_word.c @@ -144,26 +144,17 @@ int BN_add_word(BIGNUM *a, BN_ULONG w) a->neg=!(a->neg); return(i); } - /* Only expand (and risk failing) if it's possibly necessary */ - if (((BN_ULONG)(a->d[a->top - 1] + 1) == 0) && - (bn_wexpand(a,a->top+1) == NULL)) - return(0); - i=0; - for (;;) + for (i=0;w!=0 && i<a->top;i++) { - if (i >= a->top) - l=w; - else - l=(a->d[i]+w)&BN_MASK2; - a->d[i]=l; - if (w > l) - w=1; - else - break; - i++; + a->d[i] = l = (a->d[i]+w)&BN_MASK2; + w = (w>l)?1:0; } - if (i >= a->top) + if (w && i==a->top) + { + if (bn_wexpand(a,a->top+1) == NULL) return 0; a->top++; + a->d[i]=w; + } bn_check_top(a); return(1); } |