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Diffstat (limited to 'app/openssl/crypto/bn/bn_lib.c')
-rw-r--r--app/openssl/crypto/bn/bn_lib.c71
1 files changed, 52 insertions, 19 deletions
diff --git a/app/openssl/crypto/bn/bn_lib.c b/app/openssl/crypto/bn/bn_lib.c
index 5470fbe6..5461e6ee 100644
--- a/app/openssl/crypto/bn/bn_lib.c
+++ b/app/openssl/crypto/bn/bn_lib.c
@@ -139,25 +139,6 @@ const BIGNUM *BN_value_one(void)
return(&const_one);
}
-char *BN_options(void)
- {
- static int init=0;
- static char data[16];
-
- if (!init)
- {
- init++;
-#ifdef BN_LLONG
- BIO_snprintf(data,sizeof data,"bn(%d,%d)",
- (int)sizeof(BN_ULLONG)*8,(int)sizeof(BN_ULONG)*8);
-#else
- BIO_snprintf(data,sizeof data,"bn(%d,%d)",
- (int)sizeof(BN_ULONG)*8,(int)sizeof(BN_ULONG)*8);
-#endif
- }
- return(data);
- }
-
int BN_num_bits_word(BN_ULONG l)
{
static const unsigned char bits[256]={
@@ -843,3 +824,55 @@ int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b,
}
return bn_cmp_words(a,b,cl);
}
+
+/*
+ * Constant-time conditional swap of a and b.
+ * a and b are swapped if condition is not 0. The code assumes that at most one bit of condition is set.
+ * nwords is the number of words to swap. The code assumes that at least nwords are allocated in both a and b,
+ * and that no more than nwords are used by either a or b.
+ * a and b cannot be the same number
+ */
+void BN_consttime_swap(BN_ULONG condition, BIGNUM *a, BIGNUM *b, int nwords)
+ {
+ BN_ULONG t;
+ int i;
+
+ bn_wcheck_size(a, nwords);
+ bn_wcheck_size(b, nwords);
+
+ assert(a != b);
+ assert((condition & (condition - 1)) == 0);
+ assert(sizeof(BN_ULONG) >= sizeof(int));
+
+ condition = ((condition - 1) >> (BN_BITS2 - 1)) - 1;
+
+ t = (a->top^b->top) & condition;
+ a->top ^= t;
+ b->top ^= t;
+
+#define BN_CONSTTIME_SWAP(ind) \
+ do { \
+ t = (a->d[ind] ^ b->d[ind]) & condition; \
+ a->d[ind] ^= t; \
+ b->d[ind] ^= t; \
+ } while (0)
+
+
+ switch (nwords) {
+ default:
+ for (i = 10; i < nwords; i++)
+ BN_CONSTTIME_SWAP(i);
+ /* Fallthrough */
+ case 10: BN_CONSTTIME_SWAP(9); /* Fallthrough */
+ case 9: BN_CONSTTIME_SWAP(8); /* Fallthrough */
+ case 8: BN_CONSTTIME_SWAP(7); /* Fallthrough */
+ case 7: BN_CONSTTIME_SWAP(6); /* Fallthrough */
+ case 6: BN_CONSTTIME_SWAP(5); /* Fallthrough */
+ case 5: BN_CONSTTIME_SWAP(4); /* Fallthrough */
+ case 4: BN_CONSTTIME_SWAP(3); /* Fallthrough */
+ case 3: BN_CONSTTIME_SWAP(2); /* Fallthrough */
+ case 2: BN_CONSTTIME_SWAP(1); /* Fallthrough */
+ case 1: BN_CONSTTIME_SWAP(0);
+ }
+#undef BN_CONSTTIME_SWAP
+}