Many thanks! Will try. On Sat, Feb 13, 2021 at 4:54 PM Douglas E Engert <deengert@xxxxxxxxx> wrote: > > The last line: > RSA_set_ex_data(rsa, rsa_idx, k11); > > sets the pointer to the allocated k11 structure into the rsa key at index > rsa_idx > OpenSSH has allocated an rsa_index, to allow it to store OpenSSH data in > any rsa key. > The stack allows different components to also hang their own data on any > key. > (Note when the index was allocated, a free routine to free a k11 structure > was added.) > > The rsa_idx is the index into a stack in each RSA structure. > The stack allows multiple components add data to a key. > > Running under a debugger might help show how this works. > This is one of the hardest features of OpenSSL to understand. > > On 2/13/2021 9:37 AM, Dmitry Belyavskiy wrote: > > Dear Douglas, > > > > Sorry, I don't understand how it works. > > > > The RSA_get_ex_new_index allocates an index in the internal openssl > table. This index is a global variable. > > > > Then on loading a particular key we use a function pkcs11_rsa_wrap that > sets a pointer to a pkcs11_key structure identifying that particular key. > > > https://github.com/openssh/openssh-portable/blob/1bb130ed34721d46452529d094d9bbf045607d79/ssh-pkcs11.c#L486-L508 > > < > https://github.com/openssh/openssh-portable/blob/1bb130ed34721d46452529d094d9bbf045607d79/ssh-pkcs11.c#L486-L508 > > > > > > The internal openssl implementation that is used for this purpose uses a > stack. > > So basically all the _set_ex_data functions put a pointer to some data > in stack on position with idx: > > > https://github.com/openssl/openssl/blob/c8c6e7438c03b2fc24e7ead460feeaef04911fb4/crypto/ex_data.c#L369-L388 > > < > https://github.com/openssl/openssl/blob/c8c6e7438c03b2fc24e7ead460feeaef04911fb4/crypto/ex_data.c#L369-L388 > > > > > > (see the definition of OPENSSL_sk_set for details > > > https://github.com/openssl/openssl/blob/c8c6e7438c03b2fc24e7ead460feeaef04911fb4/crypto/stack/stack.c#L392-L399 > > < > https://github.com/openssl/openssl/blob/c8c6e7438c03b2fc24e7ead460feeaef04911fb4/crypto/stack/stack.c#L392-L399 > >) > > > > I think, it an easily be checked just by adding a 2nd RSA key to > regress/agent-pkcs11.sh test > > > > On Sat, Feb 13, 2021 at 4:13 PM Douglas E Engert <deengert@xxxxxxxxx > <mailto:deengert@xxxxxxxxx>> wrote: > > > > You are partially right. > > The rsa_idx, and ec_key_idx should not be set to 0, but should be set > > using RSA_get_ex_new_index() as is done later in: > > > https://github.com/openssh/openssh-portable/blame/1bb130ed34721d46452529d094d9bbf045607d79/ssh-pkcs11.c#L471 > > < > https://github.com/openssh/openssh-portable/blame/1bb130ed34721d46452529d094d9bbf045607d79/ssh-pkcs11.c#L471 > > > > > > rsa_idx = RSA_get_ex_new_index(0, "ssh-pkcs11-rsa", > > > > This then allows for multiple components to store data in a key. > > The index is not of the key, but of extra data that can be stored in > a key. > > Thus every key can have its own "ssh-pkcs11-rsa" with different data. > > > > The ec_key_idx is set in: > > > https://github.com/openssh/openssh-portable/blame/1bb130ed34721d46452529d094d9bbf045607d79/ssh-pkcs11.c#L587 > > < > https://github.com/openssh/openssh-portable/blame/1bb130ed34721d46452529d094d9bbf045607d79/ssh-pkcs11.c#L587 > > > > > > > > https://www.openssl.org/docs/man1.1.1/man3/RSA_get_ex_new_index.html > <https://www.openssl.org/docs/man1.1.1/man3/RSA_get_ex_new_index.html> > > and is also in OpenSSL-1.0.2. > > > > OpenSC/libp11 examples start here: > > https://github.com/OpenSC/libp11/blob/master/src/p11_rsa.c#L399 < > https://github.com/OpenSC/libp11/blob/master/src/p11_rsa.c#L399> > > > > https://github.com/OpenSC/libp11/blob/master/src/p11_ec.c#L155 < > https://github.com/OpenSC/libp11/blob/master/src/p11_ec.c#L155> > > > > > > On 2/13/2021 8:22 AM, Dmitry Belyavskiy wrote: > > > Dear Douglas, > > > > > > Everything is fine with methods. But I'm speaking about the > variables rsa_idx and ec_key_idx, sorry for being unclear. > > > They serve as handles in a global OpenSSL table and identify a > pkcs11_data associated with a particular key, don't they? > > > > > > On Sat, Feb 13, 2021 at 3:07 PM Douglas E Engert < > deengert@xxxxxxxxx <mailto:deengert@xxxxxxxxx> <mailto:deengert@xxxxxxxxx > <mailto:deengert@xxxxxxxxx>>> wrote: > > > > > > These lines are for METHODS, i.e. RSA_METHOD and > EC_KEY_METHOD. RSA keys can share an RSA_METHOD, > > > and EC keys can share an EC_KEY_METHOD. A method can be > copied, for example an OpenSSL engine > > > for using PKCS11, would then provide the routines in the > method to not use the default software version > > > of RSA signature or decrypting operations, but use PKCS11 to > have these operations done on the token or smart card. > > > So for RSA keys on the token, all these keys would share a > copied and modified RSA_METHOD PKCS11 method > > > where the rsa_idx in these keys is used to point to key > specific data such as PkCS11 slot and KeyIDs. > > > > > > > > > > > > On 2/12/2021 10:31 AM, Dmitry Belyavskiy wrote: > > > > Hello, > > > > > > > > Do I correctly understand that there can't be more than > one key of each > > > > type of PKCS#11? > > > > > > > > The lines > > > > > https://github.com/openssh/openssh-portable/blame/1bb130ed34721d46452529d094d9bbf045607d79/ssh-pkcs11.c#L191-L196 > > < > https://github.com/openssh/openssh-portable/blame/1bb130ed34721d46452529d094d9bbf045607d79/ssh-pkcs11.c#L191-L196 > > > > > < > https://github.com/openssh/openssh-portable/blame/1bb130ed34721d46452529d094d9bbf045607d79/ssh-pkcs11.c#L191-L196 > > < > https://github.com/openssh/openssh-portable/blame/1bb130ed34721d46452529d094d9bbf045607d79/ssh-pkcs11.c#L191-L196 > >> > > > > seem to use the global variables for RSA/ECDSA > pkcs11-related data > > > > structures. > > > > > > > > Many thanks! > > > > > > > > > > -- > > > > > > Douglas E. Engert <DEEngert@xxxxxxxxx <mailto: > DEEngert@xxxxxxxxx> <mailto:DEEngert@xxxxxxxxx <mailto:DEEngert@xxxxxxxxx > >>> > > > > > > _______________________________________________ > > > openssh-unix-dev mailing list > > > openssh-unix-dev@xxxxxxxxxxx <mailto:openssh-unix-dev@xxxxxxxxxxx> > <mailto:openssh-unix-dev@xxxxxxxxxxx <mailto:openssh-unix-dev@xxxxxxxxxxx > >> > > > https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev < > https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev> < > https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev > > <https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev>> > > > > > > > > > > > > -- > > > Dmitry Belyavskiy > > > > -- > > > > Douglas E. Engert <DEEngert@xxxxxxxxx <mailto:DEEngert@xxxxxxxxx > >> > > > > > > > > -- > > Dmitry Belyavskiy > > -- > > Douglas E. Engert <DEEngert@xxxxxxxxx> > > -- Dmitry Belyavskiy _______________________________________________ openssh-unix-dev mailing list openssh-unix-dev@xxxxxxxxxxx https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev
