1 files changed, 339 insertions, 222 deletions

diff --git a/ssh-agent.c b/ssh-agent.c
index 25f10c549..aeda656ac 100644
--- a/ssh-agent.c
+++ b/ssh-agent.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-agent.c,v 1.190 2014/07/25 21:22:03 dtucker Exp $ */
+/* $OpenBSD: ssh-agent.c,v 1.199 2015/03/04 21:12:59 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -36,6 +36,7 @@
 
 #include "includes.h"
 
+#include <sys/param.h>  /* MIN MAX */
 #include <sys/types.h>
 #include <sys/param.h>
 #include <sys/resource.h>
@@ -56,6 +57,7 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <limits.h>
 #ifdef HAVE_PATHS_H
 # include <paths.h>
 #endif
@@ -67,16 +69,20 @@
 #include <string.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"
@@ -95,9 +101,9 @@ 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;
@@ -105,7 +111,7 @@ SocketEntry *sockets = NULL;
 
 typedef struct identity {
         TAILQ_ENTRY(identity) next;
-        Key *key;
+        struct sshkey *key;
         char *comment;
         char *provider;
         time_t death;
@@ -130,8 +136,8 @@ time_t parent_alive_interval = 0;
 pid_t cleanup_pid = 0;
 
 /* pathname and directory for AUTH_SOCKET */
-char socket_name[MAXPATHLEN];
-char socket_dir[MAXPATHLEN];
+char socket_name[PATH_MAX];
+char socket_dir[PATH_MAX];
 
 /* locking */
 int locked = 0;
@@ -142,15 +148,17 @@ extern char *__progname;
 /* Default lifetime in seconds (0 == forever) */
 static long lifetime = 0;
 
+static int fingerprint_hash = SSH_FP_HASH_DEFAULT;
+
 static void
 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
@@ -176,7 +184,7 @@ 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);
@@ -184,13 +192,13 @@ 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);
@@ -203,8 +211,9 @@ confirm_key(Identity *id)
         char *p;
         int ret = -1;
 
-        p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
-        if (ask_permission("Allow use of key %s?\nKey fingerprint %s.",
+        p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT);
+        if (p != NULL &&
+            ask_permission("Allow use of key %s?\nKey fingerprint %s.",
             id->comment, p))
                 ret = 0;
         free(p);
@@ -212,37 +221,65 @@ 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
@@ -254,40 +291,48 @@ 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);
@@ -300,21 +345,22 @@ 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
 
@@ -323,54 +369,65 @@ 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;
+        struct identity *id;
+
+        if ((msg = sshbuf_new()) == NULL)
+                fatal("%s: sshbuf_new failed", __func__);
+        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;
-
-        key = key_from_blob(blob, blen);
-        if (key != NULL) {
-                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);
+                compat = SSH_BUG_SIGBLOB;
+        if ((r = sshkey_from_blob(blob, blen, &key)) != 0) {
+                error("%s: cannot parse key blob: %s", __func__, ssh_err(ok));
+                goto send;
         }
-        buffer_init(&msg);
-        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);
+        if ((id = lookup_identity(key, 2)) == NULL) {
+                verbose("%s: %s key not found", __func__, sshkey_type(key));
+                goto send;
         }
-        buffer_put_int(&e->output, buffer_len(&msg));
-        buffer_append(&e->output, buffer_ptr(&msg),
-            buffer_len(&msg));
-        buffer_free(&msg);
+        if (id->confirm && confirm_key(id) != 0) {
+                verbose("%s: user refused key", __func__);
+                goto send;
+        }
+        if ((r = sshkey_sign(id->key, &signature, &slen,
+            data, dlen, compat)) != 0) {
+                error("%s: sshkey_sign: %s", __func__, ssh_err(ok));
+                goto send;
+        }
+        /* Success */
+        ok = 0;
+ send:
+        sshkey_free(key);
+        if (ok == 0) {
+                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;
@@ -379,19 +436,27 @@ 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;
         }
@@ -415,11 +480,9 @@ 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
@@ -439,8 +502,7 @@ 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 */
@@ -474,71 +536,106 @@ reaper(void)
                 return (deadline - now);
 }
 
+/*
+ * XXX this and the corresponding serialisation function probably belongs
+ * in key.c
+ */
+#ifdef WITH_SSH1
+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;
+}
+#endif /* WITH_SSH1 */
+
 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;
@@ -549,26 +646,25 @@ 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));
@@ -582,25 +678,25 @@ 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
@@ -608,19 +704,27 @@ 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;
@@ -650,7 +754,7 @@ process_add_smartcard_key(SocketEntry *e)
                         tab->nentries++;
                         success = 1;
                 } else {
-                        key_free(k);
+                        sshkey_free(k);
                 }
                 keys[i] = NULL;
         }
@@ -658,21 +762,20 @@ 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++) {
@@ -695,9 +798,7 @@ 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 */
 
@@ -706,30 +807,31 @@ 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:
@@ -738,8 +840,7 @@ 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;
         }
@@ -765,10 +866,10 @@ process_message(SocketEntry *e)
         case SSH_AGENTC_REMOVE_RSA_IDENTITY:
                 process_remove_identity(e, 1);
                 break;
+#endif
         case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
-                process_remove_all_identities(e, 1);
+                process_remove_all_identities(e, 1); /* safe for !WITH_SSH1 */
                 break;
-#endif
         /* ssh2 */
         case SSH2_AGENTC_SIGN_REQUEST:
                 process_sign_request2(e);
@@ -798,9 +899,8 @@ 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;
         }
 }
@@ -818,9 +918,12 @@ 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;
                 }
@@ -831,9 +934,12 @@ 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;
 }
 
@@ -879,7 +985,7 @@ 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:
@@ -906,7 +1012,7 @@ 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;
@@ -942,11 +1048,11 @@ 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 == EWOULDBLOCK ||
                                     errno == EINTR))
@@ -955,7 +1061,10 @@ 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));
@@ -967,7 +1076,10 @@ 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]);
                         }
@@ -1025,8 +1137,8 @@ static void
 usage(void)
 {
         fprintf(stderr,
-            "usage: ssh-agent [-c | -s] [-d] [-a bind_address] [-t life]\n"
-            "                 [command [arg ...]]\n"
+            "usage: ssh-agent [-c | -s] [-d] [-a bind_address] [-E fingerprint_hash]\n"
+            "                 [-t life] [command [arg ...]]\n"
             "       ssh-agent [-c | -s] -k\n");
         exit(1);
 }
@@ -1069,8 +1181,13 @@ main(int ac, char **av)
         __progname = ssh_get_progname(av[0]);
         seed_rng();
 
-        while ((ch = getopt(ac, av, "cdksa:t:")) != -1) {
+        while ((ch = getopt(ac, av, "cdksE:a:t:")) != -1) {
                 switch (ch) {
+                case 'E':
+                        fingerprint_hash = ssh_digest_alg_by_name(optarg);
+                        if (fingerprint_hash == -1)
+                                fatal("Invalid hash algorithm \"%s\"", optarg);
+                        break;
                 case 'c':
                         if (s_flag)
                                 usage();