diff options
| author | Tomas Mraz <tomas@openssl.org> | 2023-07-25 15:22:48 +0200 |
|---|---|---|
| committer | Todd Short <todd.short@me.com> | 2023-07-27 09:48:22 -0400 |
| commit | 1c16253f3c3a8d1e25918c3f404aae6a5b0893de (patch) | |
| tree | 63b229c08d0885b73206c9f44b24ac5c3d2a6f0a /crypto | |
| parent | 81d10e61a4b7d5394d08a718bf7d6bae20e818fc (diff) | |
DH_check(): Do not try checking q properties if it is obviously invalid
If |q| >= |p| then the q value is obviously wrong as q
is supposed to be a prime divisor of p-1.
We check if p is overly large so this added test implies that
q is not large either when performing subsequent tests using that
q value.
Otherwise if it is too large these additional checks of the q value
such as the primality test can then trigger DoS by doing overly long
computations.
Fixes CVE-2023-3817
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
Reviewed-by: Todd Short <todd.short@me.com>
(Merged from https://github.com/openssl/openssl/pull/21550)
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/dh/dh_check.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/crypto/dh/dh_check.c b/crypto/dh/dh_check.c index 6e1ea5349a..58c1d1798b 100644 --- a/crypto/dh/dh_check.c +++ b/crypto/dh/dh_check.c @@ -143,7 +143,7 @@ int DH_check(const DH *dh, int *ret) #ifdef FIPS_MODULE return DH_check_params(dh, ret); #else - int ok = 0, r; + int ok = 0, r, q_good = 0; BN_CTX *ctx = NULL; BIGNUM *t1 = NULL, *t2 = NULL; int nid = DH_get_nid((DH *)dh); @@ -172,6 +172,13 @@ int DH_check(const DH *dh, int *ret) goto err; if (dh->params.q != NULL) { + if (BN_ucmp(dh->params.p, dh->params.q) > 0) + q_good = 1; + else + *ret |= DH_CHECK_INVALID_Q_VALUE; + } + + if (q_good) { if (BN_cmp(dh->params.g, BN_value_one()) <= 0) *ret |= DH_NOT_SUITABLE_GENERATOR; else if (BN_cmp(dh->params.g, dh->params.p) >= 0) |