[git] GnuPG - branch, master, updated. gnupg-2.2.7-370-g43b14b4
by Werner Koch
cvs at cvs.gnupg.org
Mon Feb 11 15:33:23 CET 2019
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- Log -----------------------------------------------------------------
commit 43b14b4cc227311aa77b1fc1d9577c5f7d3eda86
Author: Werner Koch <wk at gnupg.org>
Date: Mon Feb 11 15:32:54 2019 +0100
scd: Implement decryption for PIV cards.
* scd/app-piv.c (do_decipher): New.
--
Note that ECDH decryption has not been tested due to the lack of ECC
support in gpgsm.
Signed-off-by: Werner Koch <wk at gnupg.org>
diff --git a/scd/app-piv.c b/scd/app-piv.c
index 36086f5..9e355b4 100644
--- a/scd/app-piv.c
+++ b/scd/app-piv.c
@@ -2259,6 +2259,151 @@ do_auth (app_t app, const char *keyidstr,
}
+/* Decrypt the data in (INDATA,INDATALEN) and on success store the
+ * mallocated result at (R_OUTDATA,R_OUTDATALEN). */
+static gpg_error_t
+do_decipher (app_t app, const char *keyidstr,
+ gpg_error_t (*pincb)(void*, const char *, char **),
+ void *pincb_arg,
+ const void *indata_arg, size_t indatalen,
+ unsigned char **r_outdata, size_t *r_outdatalen,
+ unsigned int *r_info)
+{
+ const unsigned char *indata = indata_arg;
+ gpg_error_t err;
+ data_object_t dobj;
+ unsigned char *outdata = NULL;
+ size_t outdatalen;
+ const unsigned char *s;
+ size_t n;
+ int keyref, mechanism;
+ unsigned int framelen;
+ unsigned char *indata_buffer = NULL; /* Malloced helper. */
+ unsigned char *apdudata = NULL;
+ size_t apdudatalen;
+
+ if (!keyidstr || !*keyidstr)
+ {
+ err = gpg_error (GPG_ERR_INV_VALUE);
+ goto leave;
+ }
+
+ dobj = find_dobj_by_keyref (app, keyidstr);
+ if ((keyref = keyref_from_dobj (dobj)) == -1)
+ {
+ err = gpg_error (GPG_ERR_INV_ID);
+ goto leave;
+ }
+ if (keyref == 0x9A || keyref == 0x9C || keyref == 0x9E)
+ {
+ /* Signing only reference. We only allow '9D' and the retired
+ * cert key management DOs. */
+ err = gpg_error (GPG_ERR_INV_ID);
+ goto leave;
+ }
+
+ err = get_key_algorithm_by_dobj (app, dobj, &mechanism);
+ if (err)
+ goto leave;
+
+ switch (mechanism)
+ {
+ case PIV_ALGORITHM_ECC_P256:
+ framelen = 1+32+32;
+ break;
+ case PIV_ALGORITHM_ECC_P384:
+ framelen = 1+48+48;
+ break;
+ case PIV_ALGORITHM_RSA:
+ framelen = 2048 / 8;
+ break;
+ default:
+ err = gpg_error (GPG_ERR_INTERNAL);
+ log_debug ("piv: unknown PIV mechanism %d while decrypting\n", mechanism);
+ goto leave;
+ }
+
+ /* Check that the ciphertext has the right length; due to internal
+ * convey mechanism using MPIs leading zero bytes might have been
+ * lost. Adjust for this. Note that for ECC this actually
+ * superfluous because the first octet is always '04' to indicate an
+ * uncompressed point. */
+ if (indatalen > framelen)
+ {
+ err = gpg_error (GPG_ERR_INV_VALUE);
+ log_error ("piv: input of %zu octets too large for mechanism %d\n",
+ indatalen, mechanism);
+ goto leave;
+ }
+ if (indatalen < framelen)
+ {
+ indata_buffer = xtrycalloc (1, framelen);
+ if (!indata_buffer)
+ {
+ err = gpg_error_from_syserror ();
+ goto leave;
+ }
+ memcpy (indata_buffer+(framelen-indatalen), indata, indatalen);
+ indata = indata_buffer;
+ indatalen = framelen;
+ }
+
+ /* Now verify the Application PIN. */
+ err = verify_chv (app, 0x80, pincb, pincb_arg);
+ if (err)
+ return err;
+
+ /* Build the Dynamic Authentication Template. */
+ err = concat_tlv_list (&apdudata, &apdudatalen,
+ (int)0x7c, (size_t)0, NULL, /* Constructed. */
+ (int)0x82, (size_t)0, "",
+ mechanism == PIV_ALGORITHM_RSA?
+ (int)0x81 : (int)0x85, (size_t)indatalen, indata,
+ (int)0, (size_t)0, NULL);
+ if (err)
+ goto leave;
+
+ /* Note: the -1 requests command chaining. */
+ err = iso7816_general_authenticate (app->slot, -1,
+ mechanism, keyref,
+ apdudata, (int)apdudatalen, 0,
+ &outdata, &outdatalen);
+ if (err)
+ goto leave;
+
+ /* Parse the response. */
+ if (outdatalen && *outdata == 0x7c
+ && (s = find_tlv (outdata, outdatalen, 0x82, &n)))
+ {
+ memmove (outdata, outdata + (s - outdata), n);
+ outdatalen = n;
+ }
+ else
+ {
+ err = gpg_error (GPG_ERR_CARD);
+ log_error ("piv: response does not contain a proper result\n");
+ goto leave;
+ }
+
+ leave:
+ if (err)
+ {
+ xfree (outdata);
+ *r_outdata = NULL;
+ *r_outdatalen = 0;
+ }
+ else
+ {
+ *r_outdata = outdata;
+ *r_outdatalen = outdatalen;
+ }
+ *r_info = 0;
+ xfree (apdudata);
+ xfree (indata_buffer);
+ return err;
+}
+
+
/* Check whether a key for DOBJ already exists. We detect this by
* reading the certificate described by DOBJ. If FORCE is TRUE a
* diagnositic will be printed but no error returned if the key
@@ -2679,7 +2824,7 @@ app_select_piv (app_t app)
app->fnc.genkey = do_genkey;
app->fnc.sign = do_sign;
app->fnc.auth = do_auth;
- /* app->fnc.decipher = do_decipher; */
+ app->fnc.decipher = do_decipher;
app->fnc.change_pin = do_change_chv;
app->fnc.check_pin = do_check_chv;
-----------------------------------------------------------------------
Summary of changes:
scd/app-piv.c | 147 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 146 insertions(+), 1 deletion(-)
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