diff options
author | Andy Polyakov <appro@openssl.org> | 2012-11-09 13:58:40 +0000 |
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committer | Andy Polyakov <appro@openssl.org> | 2013-02-02 22:39:00 +0100 |
commit | b2226c6c8371bf69bb0fcb59cb7bb8562a548fba (patch) | |
tree | 3e3dc98ea94da6671dcb137f5cea49c2f214f14c /crypto/bn | |
parent | 024de2174b9a92c6d8a54d231da4d5f9ec3a4285 (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); } |