switch to sshbuf/sshkey; with & ok djm@
authormarkus <markus@openbsd.org>
Wed, 14 Jan 2015 13:09:09 +0000 (13:09 +0000)
committermarkus <markus@openbsd.org>
Wed, 14 Jan 2015 13:09:09 +0000 (13:09 +0000)
usr.bin/ssh/ssh-agent.c

index 90716bc..24ee9bc 100644 (file)
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-agent.c,v 1.193 2014/12/21 23:35:14 jmc Exp $ */
+/* $OpenBSD: ssh-agent.c,v 1.194 2015/01/14 13:09:09 markus Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 #include <time.h>
 #include <unistd.h>
 
+#include "key.h"       /* XXX for typedef */
+#include "buffer.h"    /* XXX for typedef */
+
 #include "xmalloc.h"
 #include "ssh.h"
 #include "rsa.h"
-#include "buffer.h"
-#include "key.h"
+#include "sshbuf.h"
+#include "sshkey.h"
 #include "authfd.h"
 #include "compat.h"
 #include "log.h"
 #include "misc.h"
 #include "digest.h"
+#include "ssherr.h"
 
 #ifdef ENABLE_PKCS11
 #include "ssh-pkcs11.h"
@@ -81,9 +85,9 @@ typedef enum {
 typedef struct {
        int fd;
        sock_type type;
-       Buffer input;
-       Buffer output;
-       Buffer request;
+       struct sshbuf *input;
+       struct sshbuf *output;
+       struct sshbuf *request;
 } SocketEntry;
 
 u_int sockets_alloc = 0;
@@ -91,7 +95,7 @@ SocketEntry *sockets = NULL;
 
 typedef struct identity {
        TAILQ_ENTRY(identity) next;
-       Key *key;
+       struct sshkey *key;
        char *comment;
        char *provider;
        time_t death;
@@ -136,9 +140,9 @@ close_socket(SocketEntry *e)
        close(e->fd);
        e->fd = -1;
        e->type = AUTH_UNUSED;
-       buffer_free(&e->input);
-       buffer_free(&e->output);
-       buffer_free(&e->request);
+       sshbuf_free(e->input);
+       sshbuf_free(e->output);
+       sshbuf_free(e->request);
 }
 
 static void
@@ -164,7 +168,7 @@ idtab_lookup(int version)
 static void
 free_identity(Identity *id)
 {
-       key_free(id->key);
+       sshkey_free(id->key);
        free(id->provider);
        free(id->comment);
        free(id);
@@ -172,13 +176,13 @@ free_identity(Identity *id)
 
 /* return matching private key for given public key */
 static Identity *
-lookup_identity(Key *key, int version)
+lookup_identity(struct sshkey *key, int version)
 {
        Identity *id;
 
        Idtab *tab = idtab_lookup(version);
        TAILQ_FOREACH(id, &tab->idlist, next) {
-               if (key_equal(key, id->key))
+               if (sshkey_equal(key, id->key))
                        return (id);
        }
        return (NULL);
@@ -191,7 +195,7 @@ confirm_key(Identity *id)
        char *p;
        int ret = -1;
 
-       p = key_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT);
+       p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT);
        if (ask_permission("Allow use of key %s?\nKey fingerprint %s.",
            id->comment, p))
                ret = 0;
@@ -200,37 +204,65 @@ confirm_key(Identity *id)
        return (ret);
 }
 
+static void
+send_status(SocketEntry *e, int success)
+{
+       int r;
+
+       if ((r = sshbuf_put_u32(e->output, 1)) != 0 ||
+           (r = sshbuf_put_u8(e->output, success ?
+           SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0)
+               fatal("%s: buffer error: %s", __func__, ssh_err(r));
+}
+
 /* send list of supported public keys to 'client' */
 static void
 process_request_identities(SocketEntry *e, int version)
 {
        Idtab *tab = idtab_lookup(version);
        Identity *id;
-       Buffer msg;
-
-       buffer_init(&msg);
-       buffer_put_char(&msg, (version == 1) ?
-           SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
-       buffer_put_int(&msg, tab->nentries);
+       struct sshbuf *msg;
+       int r;
+
+       if ((msg = sshbuf_new()) == NULL)
+               fatal("%s: sshbuf_new failed", __func__);
+       if ((r = sshbuf_put_u8(msg, (version == 1) ?
+           SSH_AGENT_RSA_IDENTITIES_ANSWER :
+           SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
+           (r = sshbuf_put_u32(msg, tab->nentries)) != 0)
+               fatal("%s: buffer error: %s", __func__, ssh_err(r));
        TAILQ_FOREACH(id, &tab->idlist, next) {
                if (id->key->type == KEY_RSA1) {
 #ifdef WITH_SSH1
-                       buffer_put_int(&msg, BN_num_bits(id->key->rsa->n));
-                       buffer_put_bignum(&msg, id->key->rsa->e);
-                       buffer_put_bignum(&msg, id->key->rsa->n);
+                       if ((r = sshbuf_put_u32(msg,
+                           BN_num_bits(id->key->rsa->n))) != 0 ||
+                           (r = sshbuf_put_bignum1(msg,
+                           id->key->rsa->e)) != 0 ||
+                           (r = sshbuf_put_bignum1(msg,
+                           id->key->rsa->n)) != 0)
+                               fatal("%s: buffer error: %s",
+                                   __func__, ssh_err(r));
 #endif
                } else {
                        u_char *blob;
-                       u_int blen;
-                       key_to_blob(id->key, &blob, &blen);
-                       buffer_put_string(&msg, blob, blen);
+                       size_t blen;
+
+                       if ((r = sshkey_to_blob(id->key, &blob, &blen)) != 0) {
+                               error("%s: sshkey_to_blob: %s", __func__,
+                                   ssh_err(r));
+                               continue;
+                       }
+                       if ((r = sshbuf_put_string(msg, blob, blen)) != 0)
+                               fatal("%s: buffer error: %s",
+                                   __func__, ssh_err(r));
                        free(blob);
                }
-               buffer_put_cstring(&msg, id->comment);
+               if ((r = sshbuf_put_cstring(msg, id->comment)) != 0)
+                       fatal("%s: buffer error: %s", __func__, ssh_err(r));
        }
-       buffer_put_int(&e->output, buffer_len(&msg));
-       buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
-       buffer_free(&msg);
+       if ((r = sshbuf_put_stringb(e->output, msg)) != 0)
+               fatal("%s: buffer error: %s", __func__, ssh_err(r));
+       sshbuf_free(msg);
 }
 
 #ifdef WITH_SSH1
@@ -242,40 +274,48 @@ process_authentication_challenge1(SocketEntry *e)
        u_int response_type;
        BIGNUM *challenge;
        Identity *id;
-       int i, len;
-       Buffer msg;
+       int r, len;
+       struct sshbuf *msg;
        struct ssh_digest_ctx *md;
-       Key *key;
+       struct sshkey *key;
 
-       buffer_init(&msg);
-       key = key_new(KEY_RSA1);
+       if ((msg = sshbuf_new()) == NULL)
+               fatal("%s: sshbuf_new failed", __func__);
+       if ((key = sshkey_new(KEY_RSA1)) == NULL)
+               fatal("%s: sshkey_new failed", __func__);
        if ((challenge = BN_new()) == NULL)
-               fatal("process_authentication_challenge1: BN_new failed");
+               fatal("%s: BN_new failed", __func__);
 
-       (void) buffer_get_int(&e->request);                     /* ignored */
-       buffer_get_bignum(&e->request, key->rsa->e);
-       buffer_get_bignum(&e->request, key->rsa->n);
-       buffer_get_bignum(&e->request, challenge);
+       if ((r = sshbuf_get_u32(e->request, NULL)) != 0 || /* ignored */
+           (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 ||
+           (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0 ||
+           (r = sshbuf_get_bignum1(e->request, challenge)))
+               fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
        /* Only protocol 1.1 is supported */
-       if (buffer_len(&e->request) == 0)
+       if (sshbuf_len(e->request) == 0)
                goto failure;
-       buffer_get(&e->request, session_id, 16);
-       response_type = buffer_get_int(&e->request);
+       if ((r = sshbuf_get(e->request, session_id, sizeof(session_id))) != 0 ||
+           (r = sshbuf_get_u32(e->request, &response_type)) != 0)
+               fatal("%s: buffer error: %s", __func__, ssh_err(r));
        if (response_type != 1)
                goto failure;
 
        id = lookup_identity(key, 1);
        if (id != NULL && (!id->confirm || confirm_key(id) == 0)) {
-               Key *private = id->key;
+               struct sshkey *private = id->key;
                /* Decrypt the challenge using the private key. */
-               if (rsa_private_decrypt(challenge, challenge, private->rsa) != 0)
-                       goto failure;
+               if ((r = rsa_private_decrypt(challenge, challenge,
+                   private->rsa) != 0)) {
+                       fatal("%s: rsa_public_encrypt: %s", __func__,
+                           ssh_err(r));
+                       goto failure;   /* XXX ? */
+               }
 
-               /* The response is MD5 of decrypted challenge plus session id. */
+               /* The response is MD5 of decrypted challenge plus session id */
                len = BN_num_bytes(challenge);
                if (len <= 0 || len > 32) {
-                       logit("process_authentication_challenge: bad challenge length %d", len);
+                       logit("%s: bad challenge length %d", __func__, len);
                        goto failure;
                }
                memset(buf, 0, 32);
@@ -288,21 +328,22 @@ process_authentication_challenge1(SocketEntry *e)
                ssh_digest_free(md);
 
                /* Send the response. */
-               buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE);
-               for (i = 0; i < 16; i++)
-                       buffer_put_char(&msg, mdbuf[i]);
+               if ((r = sshbuf_put_u8(msg, SSH_AGENT_RSA_RESPONSE)) != 0 ||
+                   (r = sshbuf_put(msg, mdbuf, sizeof(mdbuf))) != 0)
+                       fatal("%s: buffer error: %s", __func__, ssh_err(r));
                goto send;
        }
 
-failure:
+ failure:
        /* Unknown identity or protocol error.  Send failure. */
-       buffer_put_char(&msg, SSH_AGENT_FAILURE);
-send:
-       buffer_put_int(&e->output, buffer_len(&msg));
-       buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
-       key_free(key);
+       if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0)
+               fatal("%s: buffer error: %s", __func__, ssh_err(r));
+ send:
+       if ((r = sshbuf_put_stringb(e->output, msg)) != 0)
+               fatal("%s: buffer error: %s", __func__, ssh_err(r));
+       sshkey_free(key);
        BN_clear_free(challenge);
-       buffer_free(&msg);
+       sshbuf_free(msg);
 }
 #endif
 
@@ -311,54 +352,56 @@ static void
 process_sign_request2(SocketEntry *e)
 {
        u_char *blob, *data, *signature = NULL;
-       u_int blen, dlen, slen = 0;
-       extern int datafellows;
-       int odatafellows;
-       int ok = -1, flags;
-       Buffer msg;
-       Key *key;
-
-       datafellows = 0;
-
-       blob = buffer_get_string(&e->request, &blen);
-       data = buffer_get_string(&e->request, &dlen);
-
-       flags = buffer_get_int(&e->request);
-       odatafellows = datafellows;
+       size_t blen, dlen, slen = 0;
+       u_int compat = 0, flags;
+       int r, ok = -1;
+       struct sshbuf *msg;
+       struct sshkey *key;
+
+       if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0 ||
+           (r = sshbuf_get_string(e->request, &data, &dlen)) != 0 ||
+           (r = sshbuf_get_u32(e->request, &flags)) != 0)
+               fatal("%s: buffer error: %s", __func__, ssh_err(r));
        if (flags & SSH_AGENT_OLD_SIGNATURE)
-               datafellows = SSH_BUG_SIGBLOB;
+               compat = SSH_BUG_SIGBLOB;
 
-       key = key_from_blob(blob, blen);
-       if (key != NULL) {
+       if ((ok = sshkey_from_blob(blob, blen, &key)) != 0)
+               error("%s: cannot parse key blob: %s", __func__, ssh_err(ok));
+       else {
                Identity *id = lookup_identity(key, 2);
-               if (id != NULL && (!id->confirm || confirm_key(id) == 0))
-                       ok = key_sign(id->key, &signature, &slen, data, dlen);
-               key_free(key);
+               if (id != NULL && (!id->confirm || confirm_key(id) == 0)) {
+                       if ((ok = sshkey_sign(id->key, &signature, &slen,
+                           data, dlen, compat)) != 0)
+                               error("%s: sshkey_sign: %s",
+                                   __func__, ssh_err(ok));
+               }
+               sshkey_free(key);
        }
-       buffer_init(&msg);
+       if ((msg = sshbuf_new()) == NULL)
+               fatal("%s: sshbuf_new failed", __func__);
        if (ok == 0) {
-               buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
-               buffer_put_string(&msg, signature, slen);
-       } else {
-               buffer_put_char(&msg, SSH_AGENT_FAILURE);
-       }
-       buffer_put_int(&e->output, buffer_len(&msg));
-       buffer_append(&e->output, buffer_ptr(&msg),
-           buffer_len(&msg));
-       buffer_free(&msg);
+               if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 ||
+                   (r = sshbuf_put_string(msg, signature, slen)) != 0)
+                       fatal("%s: buffer error: %s", __func__, ssh_err(r));
+       } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0)
+               fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
+       if ((r = sshbuf_put_stringb(e->output, msg)) != 0)
+               fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
+       sshbuf_free(msg);
        free(data);
        free(blob);
        free(signature);
-       datafellows = odatafellows;
 }
 
 /* shared */
 static void
 process_remove_identity(SocketEntry *e, int version)
 {
-       u_int blen;
-       int success = 0;
-       Key *key = NULL;
+       size_t blen;
+       int r, success = 0;
+       struct sshkey *key = NULL;
        u_char *blob;
 #ifdef WITH_SSH1
        u_int bits;
@@ -367,19 +410,27 @@ process_remove_identity(SocketEntry *e, int version)
        switch (version) {
 #ifdef WITH_SSH1
        case 1:
-               key = key_new(KEY_RSA1);
-               bits = buffer_get_int(&e->request);
-               buffer_get_bignum(&e->request, key->rsa->e);
-               buffer_get_bignum(&e->request, key->rsa->n);
-
-               if (bits != key_size(key))
-                       logit("Warning: identity keysize mismatch: actual %u, announced %u",
-                           key_size(key), bits);
+               if ((key = sshkey_new(KEY_RSA1)) == NULL) {
+                       error("%s: sshkey_new failed", __func__);
+                       return;
+               }
+               if ((r = sshbuf_get_u32(e->request, &bits)) != 0 ||
+                   (r = sshbuf_get_bignum1(e->request, key->rsa->e)) != 0 ||
+                   (r = sshbuf_get_bignum1(e->request, key->rsa->n)) != 0)
+                       fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
+               if (bits != sshkey_size(key))
+                       logit("Warning: identity keysize mismatch: "
+                           "actual %u, announced %u",
+                           sshkey_size(key), bits);
                break;
 #endif /* WITH_SSH1 */
        case 2:
-               blob = buffer_get_string(&e->request, &blen);
-               key = key_from_blob(blob, blen);
+               if ((r = sshbuf_get_string(e->request, &blob, &blen)) != 0)
+                       fatal("%s: buffer error: %s", __func__, ssh_err(r));
+               if ((r = sshkey_from_blob(blob, blen, &key)) != 0)
+                       error("%s: sshkey_from_blob failed: %s",
+                           __func__, ssh_err(r));
                free(blob);
                break;
        }
@@ -403,11 +454,9 @@ process_remove_identity(SocketEntry *e, int version)
                        tab->nentries--;
                        success = 1;
                }
-               key_free(key);
+               sshkey_free(key);
        }
-       buffer_put_int(&e->output, 1);
-       buffer_put_char(&e->output,
-           success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
+       send_status(e, success);
 }
 
 static void
@@ -427,8 +476,7 @@ process_remove_all_identities(SocketEntry *e, int version)
        tab->nentries = 0;
 
        /* Send success. */
-       buffer_put_int(&e->output, 1);
-       buffer_put_char(&e->output, SSH_AGENT_SUCCESS);
+       send_status(e, 1);
 }
 
 /* removes expired keys and returns number of seconds until the next expiry */
@@ -462,71 +510,104 @@ reaper(void)
                return (deadline - now);
 }
 
+/*
+ * XXX this and the corresponding serialisation function probably belongs
+ * in key.c
+ */
+static int
+agent_decode_rsa1(struct sshbuf *m, struct sshkey **kp)
+{
+       struct sshkey *k = NULL;
+       int r = SSH_ERR_INTERNAL_ERROR;
+
+       *kp = NULL;
+       if ((k = sshkey_new_private(KEY_RSA1)) == NULL)
+               return SSH_ERR_ALLOC_FAIL;
+
+       if ((r = sshbuf_get_u32(m, NULL)) != 0 ||               /* ignored */
+           (r = sshbuf_get_bignum1(m, k->rsa->n)) != 0 ||
+           (r = sshbuf_get_bignum1(m, k->rsa->e)) != 0 ||
+           (r = sshbuf_get_bignum1(m, k->rsa->d)) != 0 ||
+           (r = sshbuf_get_bignum1(m, k->rsa->iqmp)) != 0 ||
+           /* SSH1 and SSL have p and q swapped */
+           (r = sshbuf_get_bignum1(m, k->rsa->q)) != 0 ||      /* p */
+           (r = sshbuf_get_bignum1(m, k->rsa->p)) != 0)        /* q */
+               goto out;
+
+       /* Generate additional parameters */
+       if ((r = rsa_generate_additional_parameters(k->rsa)) != 0)
+               goto out;
+       /* enable blinding */
+       if (RSA_blinding_on(k->rsa, NULL) != 1) {
+               r = SSH_ERR_LIBCRYPTO_ERROR;
+               goto out;
+       }
+
+       r = 0; /* success */
+ out:
+       if (r == 0)
+               *kp = k;
+       else
+               sshkey_free(k);
+       return r;
+}
+
 static void
 process_add_identity(SocketEntry *e, int version)
 {
        Idtab *tab = idtab_lookup(version);
        Identity *id;
-       int type, success = 0, confirm = 0;
-       char *comment;
+       int success = 0, confirm = 0;
+       u_int seconds;
+       char *comment = NULL;
        time_t death = 0;
-       Key *k = NULL;
+       struct sshkey *k = NULL;
+       u_char ctype;
+       int r = SSH_ERR_INTERNAL_ERROR;
 
        switch (version) {
 #ifdef WITH_SSH1
        case 1:
-               k = key_new_private(KEY_RSA1);
-               (void) buffer_get_int(&e->request);             /* ignored */
-               buffer_get_bignum(&e->request, k->rsa->n);
-               buffer_get_bignum(&e->request, k->rsa->e);
-               buffer_get_bignum(&e->request, k->rsa->d);
-               buffer_get_bignum(&e->request, k->rsa->iqmp);
-
-               /* SSH and SSL have p and q swapped */
-               buffer_get_bignum(&e->request, k->rsa->q);      /* p */
-               buffer_get_bignum(&e->request, k->rsa->p);      /* q */
-
-               /* Generate additional parameters */
-               if (rsa_generate_additional_parameters(k->rsa) != 0)
-                       fatal("%s: rsa_generate_additional_parameters "
-                           "error", __func__);
-
-               /* enable blinding */
-               if (RSA_blinding_on(k->rsa, NULL) != 1) {
-                       error("process_add_identity: RSA_blinding_on failed");
-                       key_free(k);
-                       goto send;
-               }
+               r = agent_decode_rsa1(e->request, &k);
                break;
 #endif /* WITH_SSH1 */
        case 2:
-               k = key_private_deserialize(&e->request);
-               if (k == NULL) {
-                       buffer_clear(&e->request);
-                       goto send;
-               }
+               r = sshkey_private_deserialize(e->request, &k);
                break;
        }
-       if (k == NULL)
-               goto send;
-       comment = buffer_get_string(&e->request, NULL);
+       if (r != 0 || k == NULL ||
+           (r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) {
+               error("%s: decode private key: %s", __func__, ssh_err(r));
+               goto err;
+       }
 
-       while (buffer_len(&e->request)) {
-               switch ((type = buffer_get_char(&e->request))) {
+       while (sshbuf_len(e->request)) {
+               if ((r = sshbuf_get_u8(e->request, &ctype)) != 0) {
+                       error("%s: buffer error: %s", __func__, ssh_err(r));
+                       goto err;
+               }
+               switch (ctype) {
                case SSH_AGENT_CONSTRAIN_LIFETIME:
-                       death = monotime() + buffer_get_int(&e->request);
+                       if ((r = sshbuf_get_u32(e->request, &seconds)) != 0) {
+                               error("%s: bad lifetime constraint: %s",
+                                   __func__, ssh_err(r));
+                               goto err;
+                       }
+                       death = monotime() + seconds;
                        break;
                case SSH_AGENT_CONSTRAIN_CONFIRM:
                        confirm = 1;
                        break;
                default:
-                       error("process_add_identity: "
-                           "Unknown constraint type %d", type);
+                       error("%s: Unknown constraint %d", __func__, ctype);
+ err:
+                       sshbuf_reset(e->request);
                        free(comment);
-                       key_free(k);
+                       sshkey_free(k);
                        goto send;
                }
        }
+
        success = 1;
        if (lifetime && !death)
                death = monotime() + lifetime;
@@ -537,26 +618,25 @@ process_add_identity(SocketEntry *e, int version)
                /* Increment the number of identities. */
                tab->nentries++;
        } else {
-               key_free(k);
+               sshkey_free(k);
                free(id->comment);
        }
        id->comment = comment;
        id->death = death;
        id->confirm = confirm;
 send:
-       buffer_put_int(&e->output, 1);
-       buffer_put_char(&e->output,
-           success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
+       send_status(e, success);
 }
 
 /* XXX todo: encrypt sensitive data with passphrase */
 static void
 process_lock_agent(SocketEntry *e, int lock)
 {
-       int success = 0;
+       int r, success = 0;
        char *passwd;
 
-       passwd = buffer_get_string(&e->request, NULL);
+       if ((r = sshbuf_get_cstring(e->request, &passwd, NULL)) != 0)
+               fatal("%s: buffer error: %s", __func__, ssh_err(r));
        if (locked && !lock && strcmp(passwd, lock_passwd) == 0) {
                locked = 0;
                explicit_bzero(lock_passwd, strlen(lock_passwd));
@@ -570,25 +650,25 @@ process_lock_agent(SocketEntry *e, int lock)
        }
        explicit_bzero(passwd, strlen(passwd));
        free(passwd);
-
-       buffer_put_int(&e->output, 1);
-       buffer_put_char(&e->output,
-           success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
+       send_status(e, success);
 }
 
 static void
 no_identities(SocketEntry *e, u_int type)
 {
-       Buffer msg;
+       struct sshbuf *msg;
+       int r;
 
-       buffer_init(&msg);
-       buffer_put_char(&msg,
+       if ((msg = sshbuf_new()) == NULL)
+               fatal("%s: sshbuf_new failed", __func__);
+       if ((r = sshbuf_put_u8(msg,
            (type == SSH_AGENTC_REQUEST_RSA_IDENTITIES) ?
-           SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
-       buffer_put_int(&msg, 0);
-       buffer_put_int(&e->output, buffer_len(&msg));
-       buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
-       buffer_free(&msg);
+           SSH_AGENT_RSA_IDENTITIES_ANSWER :
+           SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
+           (r = sshbuf_put_u32(msg, 0)) != 0 ||
+           (r = sshbuf_put_stringb(e->output, msg)) != 0)
+               fatal("%s: buffer error: %s", __func__, ssh_err(r));
+       sshbuf_free(msg);
 }
 
 #ifdef ENABLE_PKCS11
@@ -596,19 +676,27 @@ static void
 process_add_smartcard_key(SocketEntry *e)
 {
        char *provider = NULL, *pin;
-       int i, type, version, count = 0, success = 0, confirm = 0;
+       int r, i, version, count = 0, success = 0, confirm = 0;
+       u_int seconds;
        time_t death = 0;
-       Key **keys = NULL, *k;
+       u_char type;
+       struct sshkey **keys = NULL, *k;
        Identity *id;
        Idtab *tab;
 
-       provider = buffer_get_string(&e->request, NULL);
-       pin = buffer_get_string(&e->request, NULL);
+       if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 ||
+           (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0)
+               fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-       while (buffer_len(&e->request)) {
-               switch ((type = buffer_get_char(&e->request))) {
+       while (sshbuf_len(e->request)) {
+               if ((r = sshbuf_get_u8(e->request, &type)) != 0)
+                       fatal("%s: buffer error: %s", __func__, ssh_err(r));
+               switch (type) {
                case SSH_AGENT_CONSTRAIN_LIFETIME:
-                       death = monotime() + buffer_get_int(&e->request);
+                       if ((r = sshbuf_get_u32(e->request, &seconds)) != 0)
+                               fatal("%s: buffer error: %s",
+                                   __func__, ssh_err(r));
+                       death = monotime() + seconds;
                        break;
                case SSH_AGENT_CONSTRAIN_CONFIRM:
                        confirm = 1;
@@ -638,7 +726,7 @@ process_add_smartcard_key(SocketEntry *e)
                        tab->nentries++;
                        success = 1;
                } else {
-                       key_free(k);
+                       sshkey_free(k);
                }
                keys[i] = NULL;
        }
@@ -646,21 +734,20 @@ send:
        free(pin);
        free(provider);
        free(keys);
-       buffer_put_int(&e->output, 1);
-       buffer_put_char(&e->output,
-           success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
+       send_status(e, success);
 }
 
 static void
 process_remove_smartcard_key(SocketEntry *e)
 {
        char *provider = NULL, *pin = NULL;
-       int version, success = 0;
+       int r, version, success = 0;
        Identity *id, *nxt;
        Idtab *tab;
 
-       provider = buffer_get_string(&e->request, NULL);
-       pin = buffer_get_string(&e->request, NULL);
+       if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 ||
+           (r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0)
+               fatal("%s: buffer error: %s", __func__, ssh_err(r));
        free(pin);
 
        for (version = 1; version < 3; version++) {
@@ -683,9 +770,7 @@ process_remove_smartcard_key(SocketEntry *e)
                error("process_remove_smartcard_key:"
                    " pkcs11_del_provider failed");
        free(provider);
-       buffer_put_int(&e->output, 1);
-       buffer_put_char(&e->output,
-           success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
+       send_status(e, success);
 }
 #endif /* ENABLE_PKCS11 */
 
@@ -694,30 +779,31 @@ process_remove_smartcard_key(SocketEntry *e)
 static void
 process_message(SocketEntry *e)
 {
-       u_int msg_len, type;
-       u_char *cp;
+       u_int msg_len;
+       u_char type;
+       const u_char *cp;
+       int r;
 
-       if (buffer_len(&e->input) < 5)
+       if (sshbuf_len(e->input) < 5)
                return;         /* Incomplete message. */
-       cp = buffer_ptr(&e->input);
-       msg_len = get_u32(cp);
+       cp = sshbuf_ptr(e->input);
+       msg_len = PEEK_U32(cp);
        if (msg_len > 256 * 1024) {
                close_socket(e);
                return;
        }
-       if (buffer_len(&e->input) < msg_len + 4)
+       if (sshbuf_len(e->input) < msg_len + 4)
                return;
 
        /* move the current input to e->request */
-       buffer_consume(&e->input, 4);
-       buffer_clear(&e->request);
-       buffer_append(&e->request, buffer_ptr(&e->input), msg_len);
-       buffer_consume(&e->input, msg_len);
-       type = buffer_get_char(&e->request);
+       sshbuf_reset(e->request);
+       if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 ||
+           (r = sshbuf_get_u8(e->request, &type)) != 0)
+               fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
        /* check wheter agent is locked */
        if (locked && type != SSH_AGENTC_UNLOCK) {
-               buffer_clear(&e->request);
+               sshbuf_reset(e->request);
                switch (type) {
                case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
                case SSH2_AGENTC_REQUEST_IDENTITIES:
@@ -726,8 +812,7 @@ process_message(SocketEntry *e)
                        break;
                default:
                        /* send a fail message for all other request types */
-                       buffer_put_int(&e->output, 1);
-                       buffer_put_char(&e->output, SSH_AGENT_FAILURE);
+                       send_status(e, 0);
                }
                return;
        }
@@ -786,9 +871,8 @@ process_message(SocketEntry *e)
        default:
                /* Unknown message.  Respond with failure. */
                error("Unknown message %d", type);
-               buffer_clear(&e->request);
-               buffer_put_int(&e->output, 1);
-               buffer_put_char(&e->output, SSH_AGENT_FAILURE);
+               sshbuf_reset(e->request);
+               send_status(e, 0);
                break;
        }
 }
@@ -806,9 +890,12 @@ new_socket(sock_type type, int fd)
        for (i = 0; i < sockets_alloc; i++)
                if (sockets[i].type == AUTH_UNUSED) {
                        sockets[i].fd = fd;
-                       buffer_init(&sockets[i].input);
-                       buffer_init(&sockets[i].output);
-                       buffer_init(&sockets[i].request);
+                       if ((sockets[i].input = sshbuf_new()) == NULL)
+                               fatal("%s: sshbuf_new failed", __func__);
+                       if ((sockets[i].output = sshbuf_new()) == NULL)
+                               fatal("%s: sshbuf_new failed", __func__);
+                       if ((sockets[i].request = sshbuf_new()) == NULL)
+                               fatal("%s: sshbuf_new failed", __func__);
                        sockets[i].type = type;
                        return;
                }
@@ -819,9 +906,12 @@ new_socket(sock_type type, int fd)
                sockets[i].type = AUTH_UNUSED;
        sockets_alloc = new_alloc;
        sockets[old_alloc].fd = fd;
-       buffer_init(&sockets[old_alloc].input);
-       buffer_init(&sockets[old_alloc].output);
-       buffer_init(&sockets[old_alloc].request);
+       if ((sockets[old_alloc].input = sshbuf_new()) == NULL)
+               fatal("%s: sshbuf_new failed", __func__);
+       if ((sockets[old_alloc].output = sshbuf_new()) == NULL)
+               fatal("%s: sshbuf_new failed", __func__);
+       if ((sockets[old_alloc].request = sshbuf_new()) == NULL)
+               fatal("%s: sshbuf_new failed", __func__);
        sockets[old_alloc].type = type;
 }
 
@@ -867,7 +957,7 @@ prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp,
                case AUTH_SOCKET:
                case AUTH_CONNECTION:
                        FD_SET(sockets[i].fd, *fdrp);
-                       if (buffer_len(&sockets[i].output) > 0)
+                       if (sshbuf_len(sockets[i].output) > 0)
                                FD_SET(sockets[i].fd, *fdwp);
                        break;
                default:
@@ -894,7 +984,7 @@ after_select(fd_set *readset, fd_set *writeset)
        struct sockaddr_un sunaddr;
        socklen_t slen;
        char buf[1024];
-       int len, sock;
+       int len, sock, r;
        u_int i, orig_alloc;
        uid_t euid;
        gid_t egid;
@@ -930,11 +1020,11 @@ after_select(fd_set *readset, fd_set *writeset)
                        }
                        break;
                case AUTH_CONNECTION:
-                       if (buffer_len(&sockets[i].output) > 0 &&
+                       if (sshbuf_len(sockets[i].output) > 0 &&
                            FD_ISSET(sockets[i].fd, writeset)) {
                                len = write(sockets[i].fd,
-                                   buffer_ptr(&sockets[i].output),
-                                   buffer_len(&sockets[i].output));
+                                   sshbuf_ptr(sockets[i].output),
+                                   sshbuf_len(sockets[i].output));
                                if (len == -1 && (errno == EAGAIN ||
                                    errno == EINTR))
                                        continue;
@@ -942,7 +1032,10 @@ after_select(fd_set *readset, fd_set *writeset)
                                        close_socket(&sockets[i]);
                                        break;
                                }
-                               buffer_consume(&sockets[i].output, len);
+                               if ((r = sshbuf_consume(sockets[i].output,
+                                   len)) != 0)
+                                       fatal("%s: buffer error: %s",
+                                           __func__, ssh_err(r));
                        }
                        if (FD_ISSET(sockets[i].fd, readset)) {
                                len = read(sockets[i].fd, buf, sizeof(buf));
@@ -953,7 +1046,10 @@ after_select(fd_set *readset, fd_set *writeset)
                                        close_socket(&sockets[i]);
                                        break;
                                }
-                               buffer_append(&sockets[i].input, buf, len);
+                               if ((r = sshbuf_put(sockets[i].input,
+                                   buf, len)) != 0)
+                                       fatal("%s: buffer error: %s",
+                                           __func__, ssh_err(r));
                                explicit_bzero(buf, sizeof(buf));
                                process_message(&sockets[i]);
                        }