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| author | Tomas Mraz <tomas@openssl.org> | 2023-10-04 09:30:43 +0200 |
|---|---|---|
| committer | Tomas Mraz <tomas@openssl.org> | 2023-10-05 12:05:57 +0200 |
| commit | c2dbf9ef1f9cc26c5fb1540393a89a56b2469d91 (patch) | |
| tree | 75b1a54a659c96b700e64f57a53a36aa5eed5df4 | |
| parent | ff0995ca8b90765814712ccbc6eec34b648d9a2c (diff) | |
| download | openssl-c2dbf9ef1f9cc26c5fb1540393a89a56b2469d91.tar.gz | |
BN_gcd(): Avoid shifts of negative values
Fixes #22216
Thanks to Leland Mills for investigation and testing.
Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/22272)
(cherry picked from commit 0f7a3b0caa33a87c900536dc1c02fa553d2193cc)
| -rw-r--r-- | crypto/bn/bn_gcd.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/crypto/bn/bn_gcd.c b/crypto/bn/bn_gcd.c index 59d024f674..6a31ff87ef 100644 --- a/crypto/bn/bn_gcd.c +++ b/crypto/bn/bn_gcd.c @@ -611,9 +611,9 @@ int BN_gcd(BIGNUM *r, const BIGNUM *in_a, const BIGNUM *in_b, BN_CTX *ctx) for (i = 0; i < m; i++) { /* conditionally flip signs if delta is positive and g is odd */ - cond = (-delta >> (8 * sizeof(delta) - 1)) & g->d[0] & 1 + cond = ((unsigned int)-delta >> (8 * sizeof(delta) - 1)) & g->d[0] & 1 /* make sure g->top > 0 (i.e. if top == 0 then g == 0 always) */ - & (~((g->top - 1) >> (sizeof(g->top) * 8 - 1))); + & (~((unsigned int)(g->top - 1) >> (sizeof(g->top) * 8 - 1))); delta = (-cond & -delta) | ((cond - 1) & delta); r->neg ^= cond; /* swap */ @@ -625,7 +625,7 @@ int BN_gcd(BIGNUM *r, const BIGNUM *in_a, const BIGNUM *in_b, BN_CTX *ctx) goto err; BN_consttime_swap(g->d[0] & 1 /* g is odd */ /* make sure g->top > 0 (i.e. if top == 0 then g == 0 always) */ - & (~((g->top - 1) >> (sizeof(g->top) * 8 - 1))), + & (~((unsigned int)(g->top - 1) >> (sizeof(g->top) * 8 - 1))), g, temp, top); if (!BN_rshift1(g, g)) goto err; |