From 97ebe37033e8884f4cca5544a74376633c665e11 Mon Sep 17 00:00:00 2001 From: Viktor Dukhovni Date: Wed, 19 Jun 2024 21:04:11 +1000 Subject: [PATCH] Avoid type errors in EAI-related name check logic. The incorrectly typed data is read only, used in a compare operation, so neither remote code execution, nor memory content disclosure were possible. However, applications performing certificate name checks were vulnerable to denial of service. The GENERAL_TYPE data type is a union, and we must take care to access the correct member, based on `gen->type`, not all the member fields have the same structure, and a segfault is possible if the wrong member field is read. The code in question was lightly refactored with the intent to make it more obviously correct. CVE-2024-6119 (cherry picked from commit 1486960d6cdb052e4fc0109a56a0597b4e902ba1) --- crypto/x509/v3_utl.c | 78 +++++++++++++------ test/recipes/25-test_eai_data.t | 12 ++- test/recipes/25-test_eai_data/kdc-cert.pem | 21 +++++ .../25-test_eai_data/kdc-root-cert.pem | 16 ++++ test/recipes/25-test_eai_data/kdc.sh | 41 ++++++++++ 5 files changed, 142 insertions(+), 26 deletions(-) create mode 100644 test/recipes/25-test_eai_data/kdc-cert.pem create mode 100644 test/recipes/25-test_eai_data/kdc-root-cert.pem create mode 100755 test/recipes/25-test_eai_data/kdc.sh diff --git a/crypto/x509/v3_utl.c b/crypto/x509/v3_utl.c index 1a18174995..a09414c972 100644 --- a/crypto/x509/v3_utl.c +++ b/crypto/x509/v3_utl.c @@ -916,36 +916,64 @@ static int do_x509_check(X509 *x, const char *chk, size_t chklen, ASN1_STRING *cstr; gen = sk_GENERAL_NAME_value(gens, i); - if ((gen->type == GEN_OTHERNAME) && (check_type == GEN_EMAIL)) { - if (OBJ_obj2nid(gen->d.otherName->type_id) == - NID_id_on_SmtpUTF8Mailbox) { - san_present = 1; - - /* - * If it is not a UTF8String then that is unexpected and we - * treat it as no match - */ - if (gen->d.otherName->value->type == V_ASN1_UTF8STRING) { - cstr = gen->d.otherName->value->value.utf8string; - - /* Positive on success, negative on error! */ - if ((rv = do_check_string(cstr, 0, equal, flags, - chk, chklen, peername)) != 0) - break; - } - } else + switch (gen->type) { + default: + continue; + case GEN_OTHERNAME: + switch (OBJ_obj2nid(gen->d.otherName->type_id)) { + default: continue; - } else { - if ((gen->type != check_type) && (gen->type != GEN_OTHERNAME)) + case NID_id_on_SmtpUTF8Mailbox: + /*- + * https://datatracker.ietf.org/doc/html/rfc8398#section-3 + * + * Due to name constraint compatibility reasons described + * in Section 6, SmtpUTF8Mailbox subjectAltName MUST NOT + * be used unless the local-part of the email address + * contains non-ASCII characters. When the local-part is + * ASCII, rfc822Name subjectAltName MUST be used instead + * of SmtpUTF8Mailbox. This is compatible with legacy + * software that supports only rfc822Name (and not + * SmtpUTF8Mailbox). [...] + * + * SmtpUTF8Mailbox is encoded as UTF8String. + * + * If it is not a UTF8String then that is unexpected, and + * we ignore the invalid SAN (neither set san_present nor + * consider it a candidate for equality). This does mean + * that the subject CN may be considered, as would be the + * case when the malformed SmtpUtf8Mailbox SAN is instead + * simply absent. + * + * When CN-ID matching is not desirable, applications can + * choose to turn it off, doing so is at this time a best + * practice. + */ + if (check_type != GEN_EMAIL + || gen->d.otherName->value->type != V_ASN1_UTF8STRING) + continue; + alt_type = 0; + cstr = gen->d.otherName->value->value.utf8string; + break; + } + break; + case GEN_EMAIL: + if (check_type != GEN_EMAIL) continue; - } - san_present = 1; - if (check_type == GEN_EMAIL) cstr = gen->d.rfc822Name; - else if (check_type == GEN_DNS) + break; + case GEN_DNS: + if (check_type != GEN_DNS) + continue; cstr = gen->d.dNSName; - else + break; + case GEN_IPADD: + if (check_type != GEN_IPADD) + continue; cstr = gen->d.iPAddress; + break; + } + san_present = 1; /* Positive on success, negative on error! */ if ((rv = do_check_string(cstr, alt_type, equal, flags, chk, chklen, peername)) != 0) diff --git a/test/recipes/25-test_eai_data.t b/test/recipes/25-test_eai_data.t index 522982ddfb..e18735d89a 100644 --- a/test/recipes/25-test_eai_data.t +++ b/test/recipes/25-test_eai_data.t @@ -21,16 +21,18 @@ setup("test_eai_data"); #./util/wrap.pl apps/openssl verify -nameopt utf8 -no_check_time -CAfile test/recipes/25-test_eai_data/utf8_chain.pem test/recipes/25-test_eai_data/ascii_leaf.pem #./util/wrap.pl apps/openssl verify -nameopt utf8 -no_check_time -CAfile test/recipes/25-test_eai_data/ascii_chain.pem test/recipes/25-test_eai_data/utf8_leaf.pem -plan tests => 12; +plan tests => 16; require_ok(srctop_file('test','recipes','tconversion.pl')); my $folder = "test/recipes/25-test_eai_data"; my $ascii_pem = srctop_file($folder, "ascii_leaf.pem"); my $utf8_pem = srctop_file($folder, "utf8_leaf.pem"); +my $kdc_pem = srctop_file($folder, "kdc-cert.pem"); my $ascii_chain_pem = srctop_file($folder, "ascii_chain.pem"); my $utf8_chain_pem = srctop_file($folder, "utf8_chain.pem"); +my $kdc_chain_pem = srctop_file($folder, "kdc-root-cert.pem"); my $out; my $outcnt = 0; @@ -56,10 +58,18 @@ SKIP: { ok(run(app(["openssl", "verify", "-nameopt", "utf8", "-no_check_time", "-CAfile", $ascii_chain_pem, $ascii_pem]))); ok(run(app(["openssl", "verify", "-nameopt", "utf8", "-no_check_time", "-CAfile", $utf8_chain_pem, $utf8_pem]))); +ok(run(app(["openssl", "verify", "-nameopt", "utf8", "-no_check_time", "-CAfile", $kdc_chain_pem, $kdc_pem]))); ok(!run(app(["openssl", "verify", "-nameopt", "utf8", "-no_check_time", "-CAfile", $ascii_chain_pem, $utf8_pem]))); ok(!run(app(["openssl", "verify", "-nameopt", "utf8", "-no_check_time", "-CAfile", $utf8_chain_pem, $ascii_pem]))); +# Check an otherName does not get misparsed as an DNS name, (should trigger ASAN errors if violated). +ok(run(app(["openssl", "verify", "-nameopt", "utf8", "-no_check_time", "-verify_hostname", 'mx1.example.com', "-CAfile", $kdc_chain_pem, $kdc_pem]))); +# Check an otherName does not get misparsed as an email address, (should trigger ASAN errors if violated). +ok(run(app(["openssl", "verify", "-nameopt", "utf8", "-no_check_time", "-verify_email", 'joe@example.com', "-CAfile", $kdc_chain_pem, $kdc_pem]))); +# We expect SmtpUTF8Mailbox to be a UTF8 String, not an IA5String. +ok(!run(app(["openssl", "verify", "-nameopt", "utf8", "-no_check_time", "-verify_email", 'moe@example.com', "-CAfile", $kdc_chain_pem, $kdc_pem]))); + #Check that we get the expected failure return code with({ exit_checker => sub { return shift == 2; } }, sub { diff --git a/test/recipes/25-test_eai_data/kdc-cert.pem b/test/recipes/25-test_eai_data/kdc-cert.pem new file mode 100644 index 0000000000..e8a2c6f55d --- /dev/null +++ b/test/recipes/25-test_eai_data/kdc-cert.pem @@ -0,0 +1,21 @@ +-----BEGIN CERTIFICATE----- +MIIDbDCCAlSgAwIBAgIBAjANBgkqhkiG9w0BAQsFADAPMQ0wCwYDVQQDDARSb290 +MCAXDTI0MDYyMDA2MTQxNVoYDzIxMjQwNjIwMDYxNDE1WjAXMRUwEwYDVQQDDAxU +RVNULkVYQU1QTEUwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQC6wfP+ +6go79dkpo/dGLMlPZ7Gw/Q6gUYrCWZWUEgEeRVHCrqOlgUEyA+PcWas/XDPUxXry +BQlJHLvlqamAQn8gs4QPBARFYWKNiTVGyaRkgNA1N5gqyZdrP9UE+ZJmdqxRAAe8 +vvpGZWSgevPhLUiSCFYDiD0Rtji2Hm3rGUrReQFBQDEw2pNGwz9zIaxUs08kQZcx +Yzyiplz5Oau+R/6sAgUwDlrD9xOlUxx/tA/MSDIfkK8qioU11uUZtO5VjkNQy/bT +7zQMmXxWgm2MIgOs1u4YN7YGOtgqHE9v9iPHHfgrkbQDtVDGQsa8AQEhkUDSCtW9 +3VFAKx6dGNXYzFwfAgMBAAGjgcgwgcUwHQYDVR0OBBYEFFR5tZycW19DmtbL4Zqj +te1c2vZLMAkGA1UdIwQCMAAwCQYDVR0TBAIwADCBjQYDVR0RBIGFMIGCoD8GBisG +AQUCAqA1MDOgDhsMVEVTVC5FWEFNUExFoSEwH6ADAgEBoRgwFhsGa3JidGd0GwxU +RVNULkVYQU1QTEWgHQYIKwYBBQUHCAmgERYPbW9lQGV4YW1wbGUuY29tgQ9qb2VA +ZXhhbXBsZS5jb22CD214MS5leGFtcGxlLmNvbTANBgkqhkiG9w0BAQsFAAOCAQEA +T0xzVtVpRtaOzIhgzw7XQUdzWD5UEGSJJ1cBCOmKUWwDLTAouCYLFB4TbEE7MMUb +iuMy60bjmVtvfJIXorGUgSadRe5RWJ5DamJWvPA0Q9x7blnEcXqEF+9Td+ypevgU +UYHFmg83OYwxOsFXZ5cRuXMk3WCsDHQIBi6D1L6oDDZ2pfArs5mqm3thQKVlqyl1 +El3XRYEdqAz/5eCOFNfwxF0ALxjxVr/Z50StUZU8I7Zfev6+kHhyrR7dqzYJImv9 +0fTCOBEMjIETDsrA70OxAMu4V16nrWZdJdvzblS2qrt97Omkj+2kiPAJFB76RpwI +oDQ9fKfUOAmUFth2/R/eGA== +-----END CERTIFICATE----- diff --git a/test/recipes/25-test_eai_data/kdc-root-cert.pem b/test/recipes/25-test_eai_data/kdc-root-cert.pem new file mode 100644 index 0000000000..a74c96bf31 --- /dev/null +++ b/test/recipes/25-test_eai_data/kdc-root-cert.pem @@ -0,0 +1,16 @@ +-----BEGIN CERTIFICATE----- +MIICnDCCAYQCCQCBswYcrlZSHjANBgkqhkiG9w0BAQsFADAPMQ0wCwYDVQQDDARS +b290MCAXDTI0MDYyMDA2MTQxNVoYDzIxMjQwNjIwMDYxNDE1WjAPMQ0wCwYDVQQD +DARSb290MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAqRj8S4kBbIUj +61kZfi6nE35Q38U140+qt4uAiwAhKumfVHlBM0zQ98WFt5zMHIBQwIb3yjc2zj+0 +qzUnQfwm1r/RfcMmBPEti9Ge+aEMSsds2gMXziOFM8wd2aAFPy7UVE0XpEWofsRK +MGi61MKVdPSbGIxBwY9VW38/7D/wf1HtJe7y0xpuecR7GB2XAs+qST59NjuF+7wS +dLM8Hb3TATgeYbXXWsRJgwz+SPzExg5WmLnU+7y4brZ32dHtdSmkRVSgSlaIf7Xj +3Tc6Zi7I+W/JYk7hy1zUexVdWCak4PHcoWrXe0gNNN/t8VfLfMExt5z/HIylXnU7 +pGUyqZlTGQIDAQABMA0GCSqGSIb3DQEBCwUAA4IBAQAHpLF1UCRy7b6Hk0rLokxI +lgwiH9BU9mktigAGASvkbllpt+YbUbWnuYAvpHBGiP1qZtfX2r96UrSJaGO9BEzT +Gp9ThnSjoj4Srul0+s/NArU22irFLmDzbalgevAmm9gMGkdqkiIm/mXbwrPj0ncl +KGicevXryVpvaP62eZ8cc3C4p97frMmXxRX8sTdQpD/gRI7prdEILRSKveqT+AEW +7rFGM5AOevb4U8ddop8A3D/kX0wcCAIBF6jCNk3uEJ57jVcagL04kPnVfdRiedTS +vfq1DRNcD29d1H/9u0fHdSn1/+8Ep3X+afQ3C6//5NvOEaXcIGO4QSwkprQydfv8 +-----END CERTIFICATE----- diff --git a/test/recipes/25-test_eai_data/kdc.sh b/test/recipes/25-test_eai_data/kdc.sh new file mode 100755 index 0000000000..7a8dbc719f --- /dev/null +++ b/test/recipes/25-test_eai_data/kdc.sh @@ -0,0 +1,41 @@ +#! /usr/bin/env bash + +# Create a root CA, signing a leaf cert with a KDC principal otherName SAN, and +# also a non-UTF8 smtpUtf8Mailbox SAN followed by an rfc822Name SAN and a DNS +# name SAN. In the vulnerable EAI code, the KDC principal `otherName` should +# trigger ASAN errors in DNS name checks, while the non-UTF8 `smtpUtf8Mailbox` +# should likewise lead to ASAN issues with email name checks. + +rm -f root-key.pem root-cert.pem +openssl req -nodes -new -newkey rsa:2048 -keyout kdc-root-key.pem \ + -x509 -subj /CN=Root -days 36524 -out kdc-root-cert.pem + +exts=$( + printf "%s\n%s\n%s\n%s = " \ + "subjectKeyIdentifier = hash" \ + "authorityKeyIdentifier = keyid" \ + "basicConstraints = CA:false" \ + "subjectAltName" + printf "%s, " "otherName:1.3.6.1.5.2.2;SEQUENCE:kdc_princ_name" + printf "%s, " "otherName:1.3.6.1.5.5.7.8.9;IA5:moe@example.com" + printf "%s, " "email:joe@example.com" + printf "%s\n" "DNS:mx1.example.com" + printf "[kdc_princ_name]\n" + printf "realm = EXP:0, GeneralString:TEST.EXAMPLE\n" + printf "principal_name = EXP:1, SEQUENCE:kdc_principal_seq\n" + printf "[kdc_principal_seq]\n" + printf "name_type = EXP:0, INTEGER:1\n" + printf "name_string = EXP:1, SEQUENCE:kdc_principal_components\n" + printf "[kdc_principal_components]\n" + printf "princ1 = GeneralString:krbtgt\n" + printf "princ2 = GeneralString:TEST.EXAMPLE\n" + ) + +printf "%s\n" "$exts" + +openssl req -nodes -new -newkey rsa:2048 -keyout kdc-key.pem \ + -subj "/CN=TEST.EXAMPLE" | + openssl x509 -req -out kdc-cert.pem \ + -CA "kdc-root-cert.pem" -CAkey "kdc-root-key.pem" \ + -set_serial 2 -days 36524 \ + -extfile <(printf "%s\n" "$exts")