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author | egor-duda <egor-duda@users.noreply.github.com> | 2022-01-22 16:53:04 +0300 |
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committer | GitHub <noreply@github.com> | 2022-01-22 21:53:04 +0800 |
commit | 5edd2ce32e83f04b985545554412cd3a03de5547 (patch) | |
tree | c8e1fd66a6f061635f22c5619358a5ea83d0eaaa /ecdsa.c | |
parent | 18be2a65097ed8ba75d4b78769a1774e18799644 (diff) | |
download | dropbear-5edd2ce32e83f04b985545554412cd3a03de5547.tar.gz |
Implement server-side support for sk-ecdsa U2F-backed keys (#142)
* Implement server-side support for sk-ecdsa U2F-backed keys
* Fix out-of-bounds read on normal ecdsa-sha2-[identifier] keys
* Fix one more potential out-of-bounds read
* Check if nistp256 curve is used in sk-ecdsa-sha2- key
It's the only allowed curve per PROTOCOL.u2f specification
* Implement server-side support for sk-ed25519 FIDO2-backed keys
* Keys with type sk-* make no sense as host keys, so they should be
disabled
* fix typo
* Make sk-ecdsa call buf_ecdsa_verify
This reduces code duplication, the SK code just handles the
different message format.
* Reduce sk specific code
The application id can be stored in signkey, then we don't need
to call sk-specific functions from svr-authpubkey
* Remove debugging output, which causes compilation errors with DEBUG_TRACE disabled
* Proper cleanup of sk_app
Co-authored-by: Matt Johnston <matt@codeconstruct.com.au>
Diffstat (limited to 'ecdsa.c')
-rw-r--r-- | ecdsa.c | 23 |
1 files changed, 15 insertions, 8 deletions
@@ -81,18 +81,25 @@ ecc_key *buf_get_ecdsa_pub_key(buffer* buf) { struct dropbear_ecc_curve **curve; ecc_key *new_key = NULL; - /* string "ecdsa-sha2-[identifier]" */ + /* string "ecdsa-sha2-[identifier]" or "sk-ecdsa-sha2-nistp256@openssh.com" */ key_ident = (unsigned char*)buf_getstring(buf, &key_ident_len); /* string "[identifier]" */ identifier = (unsigned char*)buf_getstring(buf, &identifier_len); - if (key_ident_len != identifier_len + strlen("ecdsa-sha2-")) { - TRACE(("Bad identifier lengths")) - goto out; - } - if (memcmp(&key_ident[strlen("ecdsa-sha2-")], identifier, identifier_len) != 0) { - TRACE(("mismatching identifiers")) - goto out; + if (strcmp (key_ident, "sk-ecdsa-sha2-nistp256@openssh.com") == 0) { + if (strcmp (identifier, "nistp256") != 0) { + TRACE(("mismatching identifiers")) + goto out; + } + } else { + if (key_ident_len != identifier_len + strlen ("ecdsa-sha2-")) { + TRACE(("Bad identifier lengths")) + goto out; + } + if (memcmp(&key_ident[strlen ("ecdsa-sha2-")], identifier, identifier_len) != 0) { + TRACE(("mismatching identifiers")) + goto out; + } } for (curve = dropbear_ecc_curves; *curve; curve++) { |