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From 5cf6de5ded961302afdfac5e0a7995ae456aaef2 Mon Sep 17 00:00:00 2001
From: ap4y <mail@ap4y.me>
Date: Wed, 3 Apr 2019 21:59:31 +1300
Subject: [PATCH] Support ECC and DSA pub keys
---
src/util/support.c | 90 ++++++++++++++++++++++++++++++++++++----------
src/util/support.h | 7 ++++
2 files changed, 79 insertions(+), 18 deletions(-)
diff --git a/src/util/support.c b/src/util/support.c
index 8e576c6..773f3d8 100644
--- a/src/util/support.c
+++ b/src/util/support.c
@@ -86,26 +86,17 @@ challenge_verify_sexp (gcry_sexp_t sexp_key,
gpg_error_t err = GPG_ERR_NO_ERROR;
gcry_sexp_t sexp_signature = NULL;
gcry_sexp_t sexp_data = NULL;
- gcry_mpi_t mpi_signature = NULL;
+ int algo = pk_algo (sexp_key);
- /* Convert buffers into MPIs. */
- if (! err)
- {
- if (gcry_mpi_scan (&mpi_signature, GCRYMPI_FMT_USG, response, response_n,
- NULL))
- err = gpg_error (GPG_ERR_BAD_MPI);
- }
+ if (algo == 0)
+ return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM);
+
+ err = challenge_data (&sexp_data, algo, challenge, challenge_n);
- /* Create according S-Expressions. */
- if (! err)
- err = gcry_sexp_build (&sexp_data, NULL,
- "(data (flags pkcs1) (hash sha1 %b))",
- challenge_n, challenge);
if (! err)
- err = gcry_sexp_build (&sexp_signature, NULL, "(sig-val (rsa (s %m)))",
- mpi_signature);
+ err = response_signature (&sexp_signature, algo,
+ response, response_n);
- /* Verify. */
if (! err)
err = gcry_pk_verify (sexp_signature, sexp_data, sexp_key);
@@ -113,8 +104,6 @@ challenge_verify_sexp (gcry_sexp_t sexp_key,
gcry_sexp_release (sexp_data);
if (sexp_signature)
gcry_sexp_release (sexp_signature);
- if (mpi_signature)
- gcry_mpi_release (mpi_signature);
return err;
}
@@ -387,4 +376,69 @@ my_strlen (const char *s)
return ret;
}
+int
+pk_algo (gcry_sexp_t sexp_key)
+{
+ gcry_sexp_t sexp_data;
+ char *algoname;
+ int algo;
+
+ sexp_data = gcry_sexp_find_token (sexp_key, "public-key", 0);
+ if (!sexp_data)
+ return 0;
+
+ gcry_sexp_t sexp_tmp = gcry_sexp_cadr (sexp_data);
+ gcry_sexp_release (sexp_data);
+ sexp_data = sexp_tmp;
+
+ algoname = gcry_sexp_nth_string (sexp_data, 0);
+ gcry_sexp_release (sexp_data);
+ if (!algoname)
+ return 0;
+
+ algo = gcry_pk_map_name (algoname);
+ xfree(algoname);
+ return algo;
+}
+
+gpg_error_t
+challenge_data (gcry_sexp_t *data, int algo,
+ unsigned char *challenge, size_t challenge_n)
+{
+ if (algo == GCRY_PK_ECC)
+ {
+ return gcry_sexp_build (data, NULL,
+ "(data (flags eddsa) (hash-algo sha512) (value %b))",
+ challenge_n, challenge);
+ }
+
+ return gcry_sexp_build (data, NULL,
+ "(data (flags pkcs1) (hash sha1 %b))",
+ challenge_n, challenge);
+}
+
+gpg_error_t
+response_signature (gcry_sexp_t *sig, int algo,
+ unsigned char *response, size_t response_n)
+{
+ switch (algo)
+ {
+ case GCRY_PK_RSA:
+ return gcry_sexp_build (sig, NULL,
+ "(sig-val (rsa (s %b)))",
+ response_n, response);
+ case GCRY_PK_DSA:
+ return gcry_sexp_build (sig, NULL,
+ "(sig-val (dsa (r %b) (s %b)))",
+ response_n / 2, response,
+ response_n / 2, response + response_n / 2);
+ case GCRY_PK_ECC:
+ return gcry_sexp_build (sig, NULL,
+ "(sig-val (eddsa (r %b) (s %b)))",
+ response_n / 2, response,
+ response_n / 2, response + response_n / 2);
+ default:
+ return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM);
+ }
+}
/* END */
diff --git a/src/util/support.h b/src/util/support.h
index e25cf01..740ffa0 100644
--- a/src/util/support.h
+++ b/src/util/support.h
@@ -71,6 +71,13 @@ void char_vector_free (char **a);
int my_strlen (const char *s);
+int pk_algo (gcry_sexp_t sexp_key);
+
+gpg_error_t challenge_data (gcry_sexp_t *data, int algo,
+ unsigned char *challenge, size_t challenge_n);
+
+gpg_error_t response_signature (gcry_sexp_t *sig, int algo,
+ unsigned char *response, size_t response_n);
#endif
/* END */
--
2.20.1
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