Add ability to drop overly large packets

[onak.git] / keyid.c

diff --git a/keyid.c b/keyid.c
index d114852bd3081b2f44da24fd785ccce3bada8dfe..d5244943f8e0c4480294900ad02c8577dc0b1fa2 100644 (file)
--- a/keyid.c
+++ b/keyid.c
@@ -13,8 +13,7 @@
  * more details.
  *
  * You should have received a copy of the GNU General Public License along with
- * this program; if not, write to the Free Software Foundation, Inc., 51
- * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
 #include <string.h>
@@ -31,12 +30,26 @@
 
 #ifdef HAVE_NETTLE
 #include <nettle/md5.h>
+#include <nettle/ripemd160.h>
 #include <nettle/sha.h>
 #else
 #include "md5.h"
 #include "sha1.h"
 #endif
 
+uint64_t fingerprint2keyid(struct openpgp_fingerprint *fingerprint)
+{
+       uint64_t keyid;
+       int i;
+
+       for (keyid = 0, i = 12; i < 20; i++) {
+               keyid <<= 8;
+               keyid += fingerprint->fp[i];
+       }
+
+       return keyid;
+}
+
 
 /**
  *     get_keyid - Given a public key returns the keyid.
@@ -58,8 +71,7 @@ onak_status_t get_keyid(struct openpgp_publickey *publickey, uint64_t *keyid)
  *     which we've returned.
  */
 onak_status_t get_fingerprint(struct openpgp_packet *packet,
-       unsigned char *fingerprint,
-       size_t *len)
+       struct openpgp_fingerprint *fingerprint)
 {
        struct sha1_ctx sha_ctx;
        struct md5_ctx md5_context;
@@ -68,10 +80,8 @@ onak_status_t get_fingerprint(struct openpgp_packet *packet,
 
        if (fingerprint == NULL)
                return ONAK_E_INVALID_PARAM;
-       if (len == NULL)
-               return ONAK_E_INVALID_PARAM;
 
-       *len = 0;
+       fingerprint->length = 0;
 
        switch (packet->data[0]) {
        case 2:
@@ -89,8 +99,8 @@ onak_status_t get_fingerprint(struct openpgp_packet *packet,
                         packet->data[11+modlen] + 7) >> 3;
                md5_update(&md5_context, explen, &packet->data[12 + modlen]);
 
-               *len = 16;
-               md5_digest(&md5_context, *len, fingerprint);
+               fingerprint->length = 16;
+               md5_digest(&md5_context, fingerprint->length, fingerprint->fp);
 
                break;
 
@@ -108,8 +118,8 @@ onak_status_t get_fingerprint(struct openpgp_packet *packet,
                sha1_update(&sha_ctx, sizeof(c), &c);
                sha1_update(&sha_ctx, packet->length,
                        packet->data);
-               *len = 20;
-               sha1_digest(&sha_ctx, *len, fingerprint);
+               fingerprint->length = 20;
+               sha1_digest(&sha_ctx, fingerprint->length, fingerprint->fp);
 
                break;
        default:
@@ -128,15 +138,56 @@ onak_status_t get_packetid(struct openpgp_packet *packet, uint64_t *keyid)
 {
        int             offset = 0;
        int             i = 0;
-       size_t          length = 0;
-       unsigned char   buff[20];
+       struct openpgp_fingerprint fingerprint;
+#ifdef NETTLE_WITH_RIPEMD160
+       struct ripemd160_ctx ripemd160_context;
+       uint8_t         data;
+#endif
 
-       if (packet == NULL)
+       if (packet == NULL || packet->data == NULL)
                return ONAK_E_INVALID_PARAM;
 
        switch (packet->data[0]) {
        case 2:
        case 3:
+               /*
+                * Old versions of GnuPG would put Elgamal keys inside
+                * a V3 key structure, then generate the keyid using
+                * RIPED160.
+                */
+#ifdef NETTLE_WITH_RIPEMD160
+               if (packet->data[7] == 16) {
+                       ripemd160_init(&ripemd160_context);
+                       data = 0x99;
+                       ripemd160_update(&ripemd160_context, 1, &data);
+                       data = packet->length >> 8;
+                       ripemd160_update(&ripemd160_context, 1, &data);
+                       data = packet->length & 0xFF;
+                       ripemd160_update(&ripemd160_context, 1, &data);
+                       ripemd160_update(&ripemd160_context,
+                               packet->length,
+                               packet->data);
+
+                       ripemd160_digest(&ripemd160_context,
+                               RIPEMD160_DIGEST_SIZE,
+                               fingerprint.fp);
+                       fingerprint.length = RIPEMD160_DIGEST_SIZE;
+
+                       *keyid = fingerprint2keyid(&fingerprint);
+
+                       return ONAK_E_OK;
+               }
+#endif
+               /*
+                * Check for an RSA key; if not return an error.
+                * 1 == RSA
+                * 2 == RSA Encrypt-Only
+                * 3 == RSA Sign-Only
+                */
+               if (packet->data[7] < 1 || packet->data[7] > 3) {
+                       return ONAK_E_INVALID_PKT;
+               }
+
                /*
                 * For a type 2 or 3 key the keyid is the last 64 bits of the
                 * public modulus n, which is stored as an MPI from offset 8
@@ -150,23 +201,11 @@ onak_status_t get_packetid(struct openpgp_packet *packet, uint64_t *keyid)
                        *keyid <<= 8;
                        *keyid += packet->data[offset++];
                }
-               /*
-                * Check for an RSA key; if not return an error.
-                * 1 == RSA
-                * 2 == RSA Encrypt-Only
-                * 3 == RSA Sign-Only
-                */
-               if (packet->data[7] < 1 || packet->data[7] > 3) {
-                       return ONAK_E_INVALID_PKT;
-               }
                break;
        case 4:
-               get_fingerprint(packet, buff, &length);
-               
-               for (*keyid = 0, i = 12; i < 20; i++) {
-                       *keyid <<= 8;
-                       *keyid += buff[i];
-               }
+               get_fingerprint(packet, &fingerprint);
+
+               *keyid = fingerprint2keyid(&fingerprint);
 
                break;
        default: