GH528: "cipher -v" output is confusing.

Fix the docs, and refactor some common code.
Reviewed-by: NViktor Dukhovni <viktor@openssl.org>

CHANGES

@@ -4,6 +4,10 @@
 
  Changes between 1.0.2e and 1.1.0  [xx XXX xxxx]
 
+  *) The return value for SSL_CIPHER_description() for error conditions
+     has changed.
+     [Rich Salz]
+
   *) Support for RFC6698/RFC7671 DANE TLSA peer authentication.
 
      Obtaining and performing DNSSEC validation of TLSA records is

doc/apps/ciphers.pod

@@ -41,14 +41,12 @@ When combined with B<-s> includes cipher suites which require PSK.
 
 =item B<-v>
 
-Verbose option. List ciphers with a complete description of
-protocol version, key exchange,
-authentication, encryption and mac algorithms used along with any key size
-restrictions and whether the algorithm is classed as an "export" cipher.
+Verbose output: For each ciphersuite, list details as provided by
+L<SSL_CIPHER_description(3)>.
 
 =item B<-V>
 
-Like B<-v>, but include cipher suite codes in output (hex format).
+Like B<-v>, but include the official cipher suite values in hex.
 
 =item B<-ssl3>
 

doc/ssl/SSL_CIPHER_get_name.pod

@@ -18,26 +18,13 @@ SSL_CIPHER_get_name, SSL_CIPHER_get_bits, SSL_CIPHER_get_version, SSL_CIPHER_des
 =head1 DESCRIPTION
 
 SSL_CIPHER_get_name() returns a pointer to the name of B<cipher>. If the
-argument is the NULL pointer, a pointer to the constant value "NONE" is
-returned.
+B<cipher> is NULL, it returns "(NONE)".
 
-SSL_CIPHER_get_bits() returns the number of secret bits used for B<cipher>. If
-B<alg_bits> is not NULL, it contains the number of bits processed by the
-chosen algorithm. If B<cipher> is NULL, 0 is returned.
+SSL_CIPHER_get_bits() returns the number of secret bits used for B<cipher>.
+If B<cipher> is NULL, 0 is returned.
 
 SSL_CIPHER_get_version() returns string which indicates the SSL/TLS protocol
-version that first defined the cipher.
-This is currently B<TLSv1/SSLv3>.
-In some cases it should possibly return "TLSv1.2" but does not;
-use SSL_CIPHER_description() instead.
-If B<cipher> is NULL, "(NONE)" is returned.
-
-SSL_CIPHER_description() returns a textual description of the cipher used
-into the buffer B<buf> of length B<len> provided. B<len> must be at least
-128 bytes, otherwise a pointer to the string "Buffer too small" is
-returned. If B<buf> is NULL, a buffer of 128 bytes is allocated using
-OPENSSL_malloc(). If the allocation fails, a pointer to the string
-"OPENSSL_malloc Error" is returned.
+version that first defined the cipher.  It returns "(NONE)" if B<cipher> is NULL.
 
 SSL_CIPHER_get_cipher_nid() returns the cipher NID corresponding to B<c>.
 If there is no cipher (e.g. for ciphersuites with no encryption) then
@@ -47,16 +34,14 @@ SSL_CIPHER_get_digest_nid() returns the digest NID corresponding to the MAC
 used by B<c>. If there is no digest (e.g. for AEAD ciphersuites) then
 B<NID_undef> is returned.
 
-=head1 NOTES
-
-The number of bits processed can be different from the secret bits. An
-export cipher like e.g. EXP-RC4-MD5 has only 40 secret bits. The algorithm
-does use the full 128 bits (which would be returned for B<alg_bits>), of
-which however 88bits are fixed. The search space is hence only 40 bits.
+SSL_CIPHER_description() returns a textual description of the cipher used
+into the buffer B<buf> of length B<len> provided.  If B<buf> is provided, it
+must be at least 128 bytes, otherwise a buffer will be allocated using
+OPENSSL_malloc().  If the provided buffer is too small, or the allocation fails,
+B<NULL> is returned.
 
-The string returned by SSL_CIPHER_description() in case of success consists
-of cleartext information separated by one or more blanks in the following
-sequence:
+The string returned by SSL_CIPHER_description() consists of several fields
+separated by whitespace:
 
 =over 4
 
@@ -66,62 +51,39 @@ Textual representation of the cipher name.
 
 =item <protocol version>
 
-Protocol version: B<SSLv3>, B<TLSv1.2>. The TLSv1.0 ciphers are
-flagged with SSLv3. No new ciphers were added by TLSv1.1.
+Protocol version, such as B<TLSv1.2>, when the cipher was first defined.
 
 =item Kx=<key exchange>
 
-Key exchange method: B<RSA> (for export ciphers as B<RSA(512)> or
-B<RSA(1024)>), B<DH> (for export ciphers as B<DH(512)> or B<DH(1024)>),
-B<DH/RSA>, B<DH/DSS>, B<Fortezza>.
+Key exchange method such as B<RSA>, B<ECDHE>, etc.
 
 =item Au=<authentication>
 
-Authentication method: B<RSA>, B<DSS>, B<DH>, B<None>. None is the
+Authentication method such as B<RSA>, B<None>, etc.. None is the
 representation of anonymous ciphers.
 
 =item Enc=<symmetric encryption method>
 
-Encryption method with number of secret bits: B<DES(40)>, B<DES(56)>,
-B<3DES(168)>, B<RC4(40)>, B<RC4(56)>, B<RC4(64)>, B<RC4(128)>,
-B<RC2(40)>, B<RC2(56)>, B<RC2(128)>, B<IDEA(128)>, B<Fortezza>, B<None>.
+Encryption method, with number of secret bits, such as B<AESGCM(128)>.
 
 =item Mac=<message authentication code>
 
-Message digest: B<MD5>, B<SHA1>.
-
-=item <export flag>
-
-If the cipher is flagged exportable with respect to old US crypto
-regulations, the word "B<export>" is printed.
+Message digest, such as B<SHA256>.
 
 =back
 
-=head1 EXAMPLES
-
 Some examples for the output of SSL_CIPHER_description():
 
- DHE-RSA-DES-CBC3-SHA    SSLv3 Kx=DH       Au=RSA  Enc=3DES(168) Mac=SHA1
- DHE-DSS-DES-CBC3-SHA    SSLv3 Kx=DH       Au=DSS  Enc=3DES(168) Mac=SHA1
- RC4-MD5                 SSLv3 Kx=RSA      Au=RSA  Enc=RC4(128)  Mac=MD5
- EXP-RC4-MD5             SSLv3 Kx=RSA(512) Au=RSA  Enc=RC4(40)   Mac=MD5  export
-
-A comp[lete list can be retrieved by invoking the following command:
-
- openssl ciphers -v ALL
-
-=head1 BUGS
-
-If SSL_CIPHER_description() is called with B<cipher> being NULL, the
-library crashes.
+ ECDHE-RSA-AES256-GCM-SHA256 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AESGCM(256) Mac=AEAD
+ RSA-PSK-AES256-CBC-SHA384 TLSv1.0 Kx=RSAPSK   Au=RSA  Enc=AES(256)  Mac=SHA384
 
-If SSL_CIPHER_description() cannot handle a built-in cipher, the according
-description of the cipher property is B<unknown>. This case should not
-occur.
+=head1 HISTORY
 
-=head1 RETURN VALUES
+SSL_CIPHER_get_version() was updated to always return the correct protocol
+string in OpenSSL 1.1.
 
-See DESCRIPTION
+SSL_CIPHER_description() was changed to return B<NULL> on error,
+rather than a fixed string, in OpenSSL 1.1
 
 =head1 SEE ALSO
 

ssl/ssl_ciph.c

@@ -1581,24 +1581,24 @@ char *SSL_CIPHER_description(const SSL_CIPHER *cipher, char *buf, int len)
 {
     const char *ver;
     const char *kx, *au, *enc, *mac;
-    uint32_t alg_mkey, alg_auth, alg_enc, alg_mac, alg_ssl;
+    uint32_t alg_mkey, alg_auth, alg_enc, alg_mac;
     static const char *format =
         "%-23s %s Kx=%-8s Au=%-4s Enc=%-9s Mac=%-4s\n";
 
+    if (buf == NULL) {
+        len = 128;
+        buf = OPENSSL_malloc(len);
+        if (buf == NULL)
+            return NULL;
+    } else if (len < 128)
+        return NULL;
+
     alg_mkey = cipher->algorithm_mkey;
     alg_auth = cipher->algorithm_auth;
     alg_enc = cipher->algorithm_enc;
     alg_mac = cipher->algorithm_mac;
-    alg_ssl = cipher->algorithm_ssl;
 
-    if (alg_ssl & SSL_SSLV3)
-        ver = "SSLv3";
-    else if (alg_ssl & SSL_TLSV1)
-        ver = "TLSv1.0";
-    else if (alg_ssl & SSL_TLSV1_2)
-        ver = "TLSv1.2";
-    else
-        ver = "unknown";
+    ver = SSL_CIPHER_get_version(cipher);
 
     switch (alg_mkey) {
     case SSL_kRSA:
@@ -1768,14 +1768,6 @@ char *SSL_CIPHER_description(const SSL_CIPHER *cipher, char *buf, int len)
         break;
     }
 
-    if (buf == NULL) {
-        len = 128;
-        buf = OPENSSL_malloc(len);
-        if (buf == NULL)
-            return ("OPENSSL_malloc Error");
-    } else if (len < 128)
-        return ("Buffer too small");
-
     BIO_snprintf(buf, len, format, cipher->name, ver, kx, au, enc, mac);
 
     return (buf);
@@ -1783,15 +1775,19 @@ char *SSL_CIPHER_description(const SSL_CIPHER *cipher, char *buf, int len)
 
 char *SSL_CIPHER_get_version(const SSL_CIPHER *c)
 {
-    int i;
+    uint32_t alg_ssl;
 
     if (c == NULL)
-        return ("(NONE)");
-    i = (int)(c->id >> 24L);
-    if (i == 3)
-        return ("TLSv1/SSLv3");
-    else
-        return ("unknown");
+        return "(NONE)";
+    alg_ssl = c->algorithm_ssl;
+
+    if (alg_ssl & SSL_SSLV3)
+        return "SSLv3";
+    if (alg_ssl & SSL_TLSV1)
+        return "TLSv1.0";
+    if (alg_ssl & SSL_TLSV1_2)
+        return "TLSv1.2";
+    return "unknown";
 }
 
 /* return the actual cipher being used */