From: Joseph Sutton Date: Mon, 10 Oct 2022 07:33:09 +0000 (+1300) Subject: CVE-2022-3437 third_party/heimdal: Check for overflow in _gsskrb5_get_mech() X-Git-Tag: talloc-2.4.0~656 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d12bd2cd50b45e064e5bea5a99c826ef156b4e64;p=thirdparty%2Fsamba.git CVE-2022-3437 third_party/heimdal: Check for overflow in _gsskrb5_get_mech() If len_len is equal to total_len - 1 (i.e. the input consists only of a 0x60 byte and a length), the expression 'total_len - 1 - len_len - 1', used as the 'len' parameter to der_get_length(), will overflow to SIZE_MAX. Then der_get_length() will proceed to read, unconstrained, whatever data follows in memory. Add a check to ensure that doesn't happen. BUG: https://bugzilla.samba.org/show_bug.cgi?id=15134 Signed-off-by: Joseph Sutton Reviewed-by: Andrew Bartlett --- diff --git a/selftest/knownfail.d/heimdal-des-overflow b/selftest/knownfail.d/heimdal-des-overflow index 94a49bbee7f..a7416dc61d9 100644 --- a/selftest/knownfail.d/heimdal-des-overflow +++ b/selftest/knownfail.d/heimdal-des-overflow @@ -1,3 +1,2 @@ -^samba.unittests.auth.heimdal_gensec_unwrap_des.test_unwrap_truncated_header_0.none ^samba.unittests.auth.heimdal_gensec_unwrap_des.test_unwrap_with_padding_truncated_0.none ^samba.unittests.auth.heimdal_gensec_unwrap_des.test_unwrap_with_padding_truncated_1.none diff --git a/third_party/heimdal/lib/gssapi/krb5/decapsulate.c b/third_party/heimdal/lib/gssapi/krb5/decapsulate.c index 031a621eabc..d7b75a64222 100644 --- a/third_party/heimdal/lib/gssapi/krb5/decapsulate.c +++ b/third_party/heimdal/lib/gssapi/krb5/decapsulate.c @@ -54,6 +54,8 @@ _gsskrb5_get_mech (const u_char *ptr, e = der_get_length (p, total_len - 1, &len, &len_len); if (e || 1 + len_len + len != total_len) return -1; + if (total_len < 1 + len_len + 1) + return -1; p += len_len; if (*p++ != 0x06) return -1;