Mercurial > dropbear
annotate ecdsa.h @ 1788:1fc0012b9c38
Fix handling of replies to global requests (#112)
The current code assumes that all global requests want / need a reply.
This isn't always true and the request itself indicates if it wants a
reply or not.
It causes a specific problem with [email protected] messages.
These are sent by OpenSSH after authentication to inform the client of
potential other host keys for the host. This can be used to add a new
type of host key or to rotate host keys.
The initial information message from the server is sent as a global
request, but with want_reply set to false. This means that the server
doesn't expect an answer to this message. Instead the client needs to
send a prove request as a reply if it wants to receive proof of
ownership for the host keys.
The bug doesn't cause any current problems with due to how OpenSSH
treats receiving the failure message. It instead treats it as a
keepalive message and further ignores it.
Arguably this is a protocol violation though of Dropbear and it is only
accidental that it doesn't cause a problem with OpenSSH.
The bug was found when adding host keys support to libssh, which is more
strict protocol wise and treats the unexpected failure message an error,
also see https://gitlab.com/libssh/libssh-mirror/-/merge_requests/145
for more information.
The fix here is to honor the want_reply flag in the global request and
to only send a reply if the other side expects a reply.
author | Dirkjan Bussink <d.bussink@gmail.com> |
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date | Thu, 10 Dec 2020 16:13:13 +0100 |
parents | 99ca393afc56 |
children |
rev | line source |
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1036
deed0571cacc
DROPBEAR_ prefix for include guards to avoid collisions
Thorsten Horstmann <thorsten.horstmann@web.de>
parents:
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1 #ifndef DROPBEAR_ECDSA_H_ |
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2 #define DROPBEAR_ECDSA_H_ |
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3 |
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4 #include "includes.h" |
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5 #include "buffer.h" |
795 | 6 #include "signkey.h" |
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7 |
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8 #if DROPBEAR_ECDSA |
797
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9 |
1543
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Change default ecdsa size to 256
Matt Johnston <matt@ucc.asn.au>
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10 /* prefer 256 or 384 since those are SHOULD for |
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11 draft-ietf-curdle-ssh-kex-sha2.txt */ |
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12 #if DROPBEAR_ECC_256 |
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13 #define ECDSA_DEFAULT_SIZE 256 |
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14 #elif DROPBEAR_ECC_384 |
840
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15 #define ECDSA_DEFAULT_SIZE 384 |
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16 #elif DROPBEAR_ECC_521 |
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17 #define ECDSA_DEFAULT_SIZE 521 |
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18 #else |
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19 #error ECDSA cannot be enabled without enabling at least one size (256, 384, 521) |
794
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20 #endif |
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parents:
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21 |
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parents:
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22 ecc_key *gen_ecdsa_priv_key(unsigned int bit_size); |
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23 ecc_key *buf_get_ecdsa_pub_key(buffer* buf); |
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24 ecc_key *buf_get_ecdsa_priv_key(buffer *buf); |
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25 void buf_put_ecdsa_pub_key(buffer *buf, ecc_key *key); |
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26 void buf_put_ecdsa_priv_key(buffer *buf, ecc_key *key); |
1459
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27 enum signkey_type ecdsa_signkey_type(const ecc_key * key); |
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28 |
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Francois Perrad <francois.perrad@gadz.org>
parents:
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29 void buf_put_ecdsa_sign(buffer *buf, const ecc_key *key, const buffer *data_buf); |
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30 int buf_ecdsa_verify(buffer *buf, const ecc_key *key, const buffer *data_buf); |
846
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refactor key generation, make it generate as required.
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31 /* Returns 1 on success */ |
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32 int signkey_is_ecdsa(enum signkey_type type); |
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33 |
797
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Fix build for dropbearkey and ecdsa with certain options
Matt Johnston <matt@ucc.asn.au>
parents:
795
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34 #endif |
45f1bc96f357
Fix build for dropbearkey and ecdsa with certain options
Matt Johnston <matt@ucc.asn.au>
parents:
795
diff
changeset
|
35 |
1036
deed0571cacc
DROPBEAR_ prefix for include guards to avoid collisions
Thorsten Horstmann <thorsten.horstmann@web.de>
parents:
857
diff
changeset
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36 #endif /* DROPBEAR_ECDSA_H_ */ |