diff options
| -rw-r--r-- | includes/lib/check_weak_key.php | 96 |
1 files changed, 85 insertions, 11 deletions
diff --git a/includes/lib/check_weak_key.php b/includes/lib/check_weak_key.php index 217b885..7f96a88 100644 --- a/includes/lib/check_weak_key.php +++ b/includes/lib/check_weak_key.php @@ -126,17 +126,16 @@ function checkWeakKeyText($text) } - if ($algorithm === "rsaEncryption") - { - if (!preg_match('/^\s*RSA Public Key: \((\d+) bit\)$/m', $text, - $keysize)) + switch ((string)$algorithm) { + case "rsaEncryption": + if (!preg_match('/^\s*RSA Public Key: \((\d+) bit\)$/m', $text, $keysize)) { return failWithId("checkWeakKeyText(): Couldn't parse the RSA ". "key size.\nData:\n$text"); } else { $keysize = intval($keysize[1]); } - + if ($keysize < 2048) { return sprintf(_("The keys that you use are very small ". @@ -146,8 +145,7 @@ function checkWeakKeyText($text) "<a href='//wiki.cacert.org/WeakKeys#SmallKey'>", "</a>"); } - - + $debianVuln = checkDebianVulnerability($text, $keysize); if ($debianVuln === true) { @@ -165,7 +163,7 @@ function checkWeakKeyText($text) "checkDebianVulnerability().\nKeysize: $keysize\n". "Data:\n$text"); } - + if (!preg_match('/^\s*Exponent: (\d+) \(0x[0-9a-fA-F]+\)$/m', $text, $exponent)) { @@ -187,9 +185,9 @@ function checkWeakKeyText($text) "<a href='//wiki.cacert.org/WeakKeys#SmallExponent'>", "</a>"); } elseif (!(bccomp($exponent, "65537") >= 0 && - (bccomp($exponent, "100000") === -1 || - // speed things up if way smaller than 2^256 - bccomp($exponent, bcpow("2", "256")) === -1) )) { + (bccomp($exponent, "100000") === -1 || + // speed things up if way smaller than 2^256 + bccomp($exponent, bcpow("2", "256")) === -1) )) { // 65537 <= exponent < 2^256 recommended by NIST // not critical but log so we have some statistics about // affected users @@ -198,6 +196,82 @@ function checkWeakKeyText($text) E_USER_NOTICE); } } + + break; + +/* +//Fails to work due to outdated OpenSSL 0.9.8o +//For this to work OpenSSL 1.0.1f or newer is required +//which is currently unavailable on the systems +//If DSA2048 or longer is used the CSR hangs pending on the signer. + case "dsaEncryption": + if (!preg_match('/^\s*Public Key Algorithm:\s+dsaEncryption\s+pub:\s+([0-9a-fA-F:\s]+)\s+P:\s+([0-9a-fA-F:\s]+)\s+Q:\s+([0-9a-fA-F:\s]+)\s+G:\s+([0-9a-fA-F:\s]+)\s+$/sm', $text, $keydetail)) + { + return failWithId("checkWeakKeyText(): Couldn't parse the DSA ". + "key size.\nData:\n$text"); + } + + $key_pub = strtr(preg_replace("/[^0-9a-fA-F]/", "", $keydetail[1]), "ABCDEF", "abcdef"); + $key_P = strtr(preg_replace("/[^0-9a-fA-F]/", "", $keydetail[2]), "ABCDEF", "abcdef"); + $key_Q = strtr(preg_replace("/[^0-9a-fA-F]/", "", $keydetail[3]), "ABCDEF", "abcdef"); + $key_G = strtr(preg_replace("/[^0-9a-fA-F]/", "", $keydetail[4]), "ABCDEF", "abcdef"); + + //Verify the numbers provided by the client + $num_pub = @gmp_init($key_pub, 16); + $num_P = @gmp_init($key_P, 16); + $num_Q = @gmp_init($key_Q, 16); + $num_G = @gmp_init($key_G, 16); + + $bit_pub = ltrim(gmp_strval($num_pub, 2), "0"); + $bit_P = ltrim(gmp_strval($num_P, 2), "0"); + $bit_Q = ltrim(gmp_strval($num_Q, 2), "0"); + $bit_G = ltrim(gmp_strval($num_G, 2), "0"); + + $keysize = strlen($bit_P); + + if ($keysize < 2048) { + return sprintf(_("The keys that you use are very small ". + "and therefore insecure. Please generate stronger ". + "keys. More information about this issue can be ". + "found in %sthe wiki%s"), + "<a href='//wiki.cacert.org/WeakKeys#SmallKey'>", + "</a>"); + } + + //Following checks based on description of key generation in Wikipedia + //These checks do not ensure a strong key, but at least check for enough sanity in the key material + // cf. https://en.wikipedia.org/wiki/Digital_Signature_Algorithm#Key_generation + + //Check that P is prime + if(!gmp_testprime($num_P)) { + return failWithId("checkWeakKeyText(): The supplied DSA ". + "key does seem to have a non-prime public modulus.\nData:\n$text"); + } + + //Check that Q is prime + if(!gmp_testprime($num_Q)) { + return failWithId("checkWeakKeyText(): The supplied DSA ". + "key does seem to have a non-prime Q-value.\nData:\n$text"); + } + + //Check if P-1 is diviseable by Q + if(0 !== gmp_cmp("1", gmp_mod($num_P, $num_Q))) { + return failWithId("checkWeakKeyText(): The supplied DSA ". + "key does seem to have P mod Q === 1 (i.e. P-1 is not diviseable by Q).\nData:\n$text"); + } + + //Check the numbers are all less than the public modulus P + if(0 <= gmp_cmp($num_Q, $num_P)) || 0 <= gmp_cmp($num_G, $num_P)) || 0 <= gmp_cmp($num_Y, $num_P))) { + return failWithId("checkWeakKeyText(): The supplied DSA ". + "key does seem to be normalized to have Q < P, G < P and Y < P.\nData:\n$text"); + } + + break; +*/ + + default: + return _("The keys you supplied use an unrecognized algorithm. ". + "For security reasons these keys can not be signed by CAcert."); } /* No weakness found */ |