1 files changed, 333 insertions, 259 deletions

diff --git a/sftp-server.c b/sftp-server.c
index 0177130cf..4f735cd93 100644
--- a/sftp-server.c
+++ b/sftp-server.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp-server.c,v 1.103 2014/01/17 06:23:24 dtucker Exp $ */
+/* $OpenBSD: sftp-server.c,v 1.105 2015/01/20 23:14:00 deraadt Exp $ */
 /*
  * Copyright (c) 2000-2004 Markus Friedl.  All rights reserved.
  *
@@ -17,8 +17,8 @@
 
 #include "includes.h"
 
+#include <sys/param.h>  /* MIN */
 #include <sys/types.h>
-#include <sys/param.h>
 #include <sys/stat.h>
 #ifdef HAVE_SYS_TIME_H
 # include <sys/time.h>
@@ -46,7 +46,8 @@
 #include <stdarg.h>
 
 #include "xmalloc.h"
-#include "buffer.h"
+#include "sshbuf.h"
+#include "ssherr.h"
 #include "log.h"
 #include "misc.h"
 #include "match.h"
@@ -55,11 +56,6 @@
 #include "sftp.h"
 #include "sftp-common.h"
 
-/* helper */
-#define get_int64()                     buffer_get_int64(&iqueue);
-#define get_int()                       buffer_get_int(&iqueue);
-#define get_string(lenp)                buffer_get_string(&iqueue, lenp);
-
 /* Our verbosity */
 static LogLevel log_level = SYSLOG_LEVEL_ERROR;
 
@@ -68,8 +64,8 @@ static struct passwd *pw = NULL;
 static char *client_addr = NULL;
 
 /* input and output queue */
-static Buffer iqueue;
-static Buffer oqueue;
+struct sshbuf *iqueue;
+struct sshbuf *oqueue;
 
 /* Version of client */
 static u_int version;
@@ -275,12 +271,6 @@ string_from_portable(int pflags)
         return ret;
 }
 
-static Attrib *
-get_attrib(void)
-{
-        return decode_attrib(&iqueue);
-}
-
 /* handle handles */
 
 typedef struct Handle Handle;
@@ -344,7 +334,7 @@ handle_is_ok(int i, int type)
 }
 
 static int
-handle_to_string(int handle, char **stringp, int *hlenp)
+handle_to_string(int handle, u_char **stringp, int *hlenp)
 {
         if (stringp == NULL || hlenp == NULL)
                 return -1;
@@ -355,7 +345,7 @@ handle_to_string(int handle, char **stringp, int *hlenp)
 }
 
 static int
-handle_from_string(const char *handle, u_int hlen)
+handle_from_string(const u_char *handle, u_int hlen)
 {
         int val;
 
@@ -477,29 +467,31 @@ handle_log_exit(void)
 }
 
 static int
-get_handle(void)
+get_handle(struct sshbuf *queue, int *hp)
 {
-        char *handle;
-        int val = -1;
-        u_int hlen;
+        u_char *handle;
+        int r;
+        size_t hlen;
 
-        handle = get_string(&hlen);
+        *hp = -1;
+        if ((r = sshbuf_get_string(queue, &handle, &hlen)) != 0)
+                return r;
         if (hlen < 256)
-                val = handle_from_string(handle, hlen);
+                *hp = handle_from_string(handle, hlen);
         free(handle);
-        return val;
+        return 0;
 }
 
 /* send replies */
 
 static void
-send_msg(Buffer *m)
+send_msg(struct sshbuf *m)
 {
-        int mlen = buffer_len(m);
+        int r;
 
-        buffer_put_int(&oqueue, mlen);
-        buffer_append(&oqueue, buffer_ptr(m), mlen);
-        buffer_consume(m, mlen);
+        if ((r = sshbuf_put_stringb(oqueue, m)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
+        sshbuf_reset(m);
 }
 
 static const char *
@@ -523,38 +515,46 @@ status_to_message(u_int32_t status)
 static void
 send_status(u_int32_t id, u_int32_t status)
 {
-        Buffer msg;
+        struct sshbuf *msg;
+        int r;
 
         debug3("request %u: sent status %u", id, status);
         if (log_level > SYSLOG_LEVEL_VERBOSE ||
             (status != SSH2_FX_OK && status != SSH2_FX_EOF))
                 logit("sent status %s", status_to_message(status));
-        buffer_init(&msg);
-        buffer_put_char(&msg, SSH2_FXP_STATUS);
-        buffer_put_int(&msg, id);
-        buffer_put_int(&msg, status);
+        if ((msg = sshbuf_new()) == NULL)
+                fatal("%s: sshbuf_new failed", __func__);
+        if ((r = sshbuf_put_u8(msg, SSH2_FXP_STATUS)) != 0 ||
+            (r = sshbuf_put_u32(msg, id)) != 0 ||
+            (r = sshbuf_put_u32(msg, status)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
         if (version >= 3) {
-                buffer_put_cstring(&msg, status_to_message(status));
-                buffer_put_cstring(&msg, "");
+                if ((r = sshbuf_put_cstring(msg,
+                    status_to_message(status))) != 0 ||
+                    (r = sshbuf_put_cstring(msg, "")) != 0)
+                        fatal("%s: buffer error: %s", __func__, ssh_err(r));
         }
-        send_msg(&msg);
-        buffer_free(&msg);
+        send_msg(msg);
+        sshbuf_free(msg);
 }
 static void
-send_data_or_handle(char type, u_int32_t id, const char *data, int dlen)
+send_data_or_handle(char type, u_int32_t id, const u_char *data, int dlen)
 {
-        Buffer msg;
-
-        buffer_init(&msg);
-        buffer_put_char(&msg, type);
-        buffer_put_int(&msg, id);
-        buffer_put_string(&msg, data, dlen);
-        send_msg(&msg);
-        buffer_free(&msg);
+        struct sshbuf *msg;
+        int r;
+
+        if ((msg = sshbuf_new()) == NULL)
+                fatal("%s: sshbuf_new failed", __func__);
+        if ((r = sshbuf_put_u8(msg, type)) != 0 ||
+            (r = sshbuf_put_u32(msg, id)) != 0 ||
+            (r = sshbuf_put_string(msg, data, dlen)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
+        send_msg(msg);
+        sshbuf_free(msg);
 }
 
 static void
-send_data(u_int32_t id, const char *data, int dlen)
+send_data(u_int32_t id, const u_char *data, int dlen)
 {
         debug("request %u: sent data len %d", id, dlen);
         send_data_or_handle(SSH2_FXP_DATA, id, data, dlen);
@@ -563,7 +563,7 @@ send_data(u_int32_t id, const char *data, int dlen)
 static void
 send_handle(u_int32_t id, int handle)
 {
-        char *string;
+        u_char *string;
         int hlen;
 
         handle_to_string(handle, &string, &hlen);
@@ -575,62 +575,71 @@ send_handle(u_int32_t id, int handle)
 static void
 send_names(u_int32_t id, int count, const Stat *stats)
 {
-        Buffer msg;
-        int i;
-
-        buffer_init(&msg);
-        buffer_put_char(&msg, SSH2_FXP_NAME);
-        buffer_put_int(&msg, id);
-        buffer_put_int(&msg, count);
+        struct sshbuf *msg;
+        int i, r;
+
+        if ((msg = sshbuf_new()) == NULL)
+                fatal("%s: sshbuf_new failed", __func__);
+        if ((r = sshbuf_put_u8(msg, SSH2_FXP_NAME)) != 0 ||
+            (r = sshbuf_put_u32(msg, id)) != 0 ||
+            (r = sshbuf_put_u32(msg, count)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
         debug("request %u: sent names count %d", id, count);
         for (i = 0; i < count; i++) {
-                buffer_put_cstring(&msg, stats[i].name);
-                buffer_put_cstring(&msg, stats[i].long_name);
-                encode_attrib(&msg, &stats[i].attrib);
+                if ((r = sshbuf_put_cstring(msg, stats[i].name)) != 0 ||
+                    (r = sshbuf_put_cstring(msg, stats[i].long_name)) != 0 ||
+                    (r = encode_attrib(msg, &stats[i].attrib)) != 0)
+                        fatal("%s: buffer error: %s", __func__, ssh_err(r));
         }
-        send_msg(&msg);
-        buffer_free(&msg);
+        send_msg(msg);
+        sshbuf_free(msg);
 }
 
 static void
 send_attrib(u_int32_t id, const Attrib *a)
 {
-        Buffer msg;
+        struct sshbuf *msg;
+        int r;
 
         debug("request %u: sent attrib have 0x%x", id, a->flags);
-        buffer_init(&msg);
-        buffer_put_char(&msg, SSH2_FXP_ATTRS);
-        buffer_put_int(&msg, id);
-        encode_attrib(&msg, a);
-        send_msg(&msg);
-        buffer_free(&msg);
+        if ((msg = sshbuf_new()) == NULL)
+                fatal("%s: sshbuf_new failed", __func__);
+        if ((r = sshbuf_put_u8(msg, SSH2_FXP_ATTRS)) != 0 ||
+            (r = sshbuf_put_u32(msg, id)) != 0 ||
+            (r = encode_attrib(msg, a)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
+        send_msg(msg);
+        sshbuf_free(msg);
 }
 
 static void
 send_statvfs(u_int32_t id, struct statvfs *st)
 {
-        Buffer msg;
+        struct sshbuf *msg;
         u_int64_t flag;
+        int r;
 
         flag = (st->f_flag & ST_RDONLY) ? SSH2_FXE_STATVFS_ST_RDONLY : 0;
         flag |= (st->f_flag & ST_NOSUID) ? SSH2_FXE_STATVFS_ST_NOSUID : 0;
 
-        buffer_init(&msg);
-        buffer_put_char(&msg, SSH2_FXP_EXTENDED_REPLY);
-        buffer_put_int(&msg, id);
-        buffer_put_int64(&msg, st->f_bsize);
-        buffer_put_int64(&msg, st->f_frsize);
-        buffer_put_int64(&msg, st->f_blocks);
-        buffer_put_int64(&msg, st->f_bfree);
-        buffer_put_int64(&msg, st->f_bavail);
-        buffer_put_int64(&msg, st->f_files);
-        buffer_put_int64(&msg, st->f_ffree);
-        buffer_put_int64(&msg, st->f_favail);
-        buffer_put_int64(&msg, FSID_TO_ULONG(st->f_fsid));
-        buffer_put_int64(&msg, flag);
-        buffer_put_int64(&msg, st->f_namemax);
-        send_msg(&msg);
-        buffer_free(&msg);
+        if ((msg = sshbuf_new()) == NULL)
+                fatal("%s: sshbuf_new failed", __func__);
+        if ((r = sshbuf_put_u8(msg, SSH2_FXP_EXTENDED_REPLY)) != 0 ||
+            (r = sshbuf_put_u32(msg, id)) != 0 ||
+            (r = sshbuf_put_u64(msg, st->f_bsize)) != 0 ||
+            (r = sshbuf_put_u64(msg, st->f_frsize)) != 0 ||
+            (r = sshbuf_put_u64(msg, st->f_blocks)) != 0 ||
+            (r = sshbuf_put_u64(msg, st->f_bfree)) != 0 ||
+            (r = sshbuf_put_u64(msg, st->f_bavail)) != 0 ||
+            (r = sshbuf_put_u64(msg, st->f_files)) != 0 ||
+            (r = sshbuf_put_u64(msg, st->f_ffree)) != 0 ||
+            (r = sshbuf_put_u64(msg, st->f_favail)) != 0 ||
+            (r = sshbuf_put_u64(msg, FSID_TO_ULONG(st->f_fsid))) != 0 ||
+            (r = sshbuf_put_u64(msg, flag)) != 0 ||
+            (r = sshbuf_put_u64(msg, st->f_namemax)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
+        send_msg(msg);
+        sshbuf_free(msg);
 }
 
 /* parse incoming */
@@ -638,53 +647,59 @@ send_statvfs(u_int32_t id, struct statvfs *st)
 static void
 process_init(void)
 {
-        Buffer msg;
+        struct sshbuf *msg;
+        int r;
 
-        version = get_int();
+        if ((r = sshbuf_get_u32(iqueue, &version)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
         verbose("received client version %u", version);
-        buffer_init(&msg);
-        buffer_put_char(&msg, SSH2_FXP_VERSION);
-        buffer_put_int(&msg, SSH2_FILEXFER_VERSION);
-        /* POSIX rename extension */
-        buffer_put_cstring(&msg, "posix-rename@openssh.com");
-        buffer_put_cstring(&msg, "1"); /* version */
-        /* statvfs extension */
-        buffer_put_cstring(&msg, "statvfs@openssh.com");
-        buffer_put_cstring(&msg, "2"); /* version */
-        /* fstatvfs extension */
-        buffer_put_cstring(&msg, "fstatvfs@openssh.com");
-        buffer_put_cstring(&msg, "2"); /* version */
-        /* hardlink extension */
-        buffer_put_cstring(&msg, "hardlink@openssh.com");
-        buffer_put_cstring(&msg, "1"); /* version */
-        /* fsync extension */
-        buffer_put_cstring(&msg, "fsync@openssh.com");
-        buffer_put_cstring(&msg, "1"); /* version */
-        send_msg(&msg);
-        buffer_free(&msg);
+        if ((msg = sshbuf_new()) == NULL)
+                fatal("%s: sshbuf_new failed", __func__);
+        if ((r = sshbuf_put_u8(msg, SSH2_FXP_VERSION)) != 0 ||
+            (r = sshbuf_put_u32(msg, SSH2_FILEXFER_VERSION)) != 0 ||
+            /* POSIX rename extension */
+            (r = sshbuf_put_cstring(msg, "posix-rename@openssh.com")) != 0 ||
+            (r = sshbuf_put_cstring(msg, "1")) != 0 || /* version */
+            /* statvfs extension */
+            (r = sshbuf_put_cstring(msg, "statvfs@openssh.com")) != 0 ||
+            (r = sshbuf_put_cstring(msg, "2")) != 0 || /* version */
+            /* fstatvfs extension */
+            (r = sshbuf_put_cstring(msg, "fstatvfs@openssh.com")) != 0 ||
+            (r = sshbuf_put_cstring(msg, "2")) != 0 || /* version */
+            /* hardlink extension */
+            (r = sshbuf_put_cstring(msg, "hardlink@openssh.com")) != 0 ||
+            (r = sshbuf_put_cstring(msg, "1")) != 0 || /* version */
+            /* fsync extension */
+            (r = sshbuf_put_cstring(msg, "fsync@openssh.com")) != 0 ||
+            (r = sshbuf_put_cstring(msg, "1")) != 0) /* version */
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
+        send_msg(msg);
+        sshbuf_free(msg);
 }
 
 static void
 process_open(u_int32_t id)
 {
         u_int32_t pflags;
-        Attrib *a;
+        Attrib a;
         char *name;
-        int handle, fd, flags, mode, status = SSH2_FX_FAILURE;
+        int r, handle, fd, flags, mode, status = SSH2_FX_FAILURE;
+
+        if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
+            (r = sshbuf_get_u32(iqueue, &pflags)) != 0 || /* portable flags */
+            (r = decode_attrib(iqueue, &a)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-        name = get_string(NULL);
-        pflags = get_int();             /* portable flags */
         debug3("request %u: open flags %d", id, pflags);
-        a = get_attrib();
         flags = flags_from_portable(pflags);
-        mode = (a->flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ? a->perm : 0666;
+        mode = (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ? a.perm : 0666;
         logit("open \"%s\" flags %s mode 0%o",
             name, string_from_portable(pflags), mode);
         if (readonly &&
             ((flags & O_ACCMODE) == O_WRONLY ||
             (flags & O_ACCMODE) == O_RDWR)) {
                 verbose("Refusing open request in read-only mode");
-                status = SSH2_FX_PERMISSION_DENIED;
+                status = SSH2_FX_PERMISSION_DENIED;
         } else {
                 fd = open(name, flags, mode);
                 if (fd < 0) {
@@ -707,9 +722,11 @@ process_open(u_int32_t id)
 static void
 process_close(u_int32_t id)
 {
-        int handle, ret, status = SSH2_FX_FAILURE;
+        int r, handle, ret, status = SSH2_FX_FAILURE;
+
+        if ((r = get_handle(iqueue, &handle)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-        handle = get_handle();
         debug3("request %u: close handle %u", id, handle);
         handle_log_close(handle, NULL);
         ret = handle_close(handle);
@@ -720,14 +737,15 @@ process_close(u_int32_t id)
 static void
 process_read(u_int32_t id)
 {
-        char buf[64*1024];
+        u_char buf[64*1024];
         u_int32_t len;
-        int handle, fd, ret, status = SSH2_FX_FAILURE;
+        int r, handle, fd, ret, status = SSH2_FX_FAILURE;
         u_int64_t off;
 
-        handle = get_handle();
-        off = get_int64();
-        len = get_int();
+        if ((r = get_handle(iqueue, &handle)) != 0 ||
+            (r = sshbuf_get_u64(iqueue, &off)) != 0 ||
+            (r = sshbuf_get_u32(iqueue, &len)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
         debug("request %u: read \"%s\" (handle %d) off %llu len %d",
             id, handle_to_name(handle), handle, (unsigned long long)off, len);
@@ -761,18 +779,19 @@ static void
 process_write(u_int32_t id)
 {
         u_int64_t off;
-        u_int len;
-        int handle, fd, ret, status;
-        char *data;
+        size_t len;
+        int r, handle, fd, ret, status;
+        u_char *data;
 
-        handle = get_handle();
-        off = get_int64();
-        data = get_string(&len);
+        if ((r = get_handle(iqueue, &handle)) != 0 ||
+            (r = sshbuf_get_u64(iqueue, &off)) != 0 ||
+            (r = sshbuf_get_string(iqueue, &data, &len)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-        debug("request %u: write \"%s\" (handle %d) off %llu len %d",
+        debug("request %u: write \"%s\" (handle %d) off %llu len %zu",
             id, handle_to_name(handle), handle, (unsigned long long)off, len);
         fd = handle_to_fd(handle);
-        
+
         if (fd < 0)
                 status = SSH2_FX_FAILURE;
         else {
@@ -805,13 +824,15 @@ process_do_stat(u_int32_t id, int do_lstat)
         Attrib a;
         struct stat st;
         char *name;
-        int ret, status = SSH2_FX_FAILURE;
+        int r, status = SSH2_FX_FAILURE;
+
+        if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-        name = get_string(NULL);
         debug3("request %u: %sstat", id, do_lstat ? "l" : "");
         verbose("%sstat name \"%s\"", do_lstat ? "l" : "", name);
-        ret = do_lstat ? lstat(name, &st) : stat(name, &st);
-        if (ret < 0) {
+        r = do_lstat ? lstat(name, &st) : stat(name, &st);
+        if (r < 0) {
                 status = errno_to_portable(errno);
         } else {
                 stat_to_attrib(&st, &a);
@@ -840,15 +861,16 @@ process_fstat(u_int32_t id)
 {
         Attrib a;
         struct stat st;
-        int fd, ret, handle, status = SSH2_FX_FAILURE;
+        int fd, r, handle, status = SSH2_FX_FAILURE;
 
-        handle = get_handle();
+        if ((r = get_handle(iqueue, &handle)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
         debug("request %u: fstat \"%s\" (handle %u)",
             id, handle_to_name(handle), handle);
         fd = handle_to_fd(handle);
         if (fd >= 0) {
-                ret = fstat(fd, &st);
-                if (ret < 0) {
+                r = fstat(fd, &st);
+                if (r < 0) {
                         status = errno_to_portable(errno);
                 } else {
                         stat_to_attrib(&st, &a);
@@ -875,42 +897,44 @@ attrib_to_tv(const Attrib *a)
 static void
 process_setstat(u_int32_t id)
 {
-        Attrib *a;
+        Attrib a;
         char *name;
-        int status = SSH2_FX_OK, ret;
+        int r, status = SSH2_FX_OK;
+
+        if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
+            (r = decode_attrib(iqueue, &a)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-        name = get_string(NULL);
-        a = get_attrib();
         debug("request %u: setstat name \"%s\"", id, name);
-        if (a->flags & SSH2_FILEXFER_ATTR_SIZE) {
+        if (a.flags & SSH2_FILEXFER_ATTR_SIZE) {
                 logit("set \"%s\" size %llu",
-                    name, (unsigned long long)a->size);
-                ret = truncate(name, a->size);
-                if (ret == -1)
+                    name, (unsigned long long)a.size);
+                r = truncate(name, a.size);
+                if (r == -1)
                         status = errno_to_portable(errno);
         }
-        if (a->flags & SSH2_FILEXFER_ATTR_PERMISSIONS) {
-                logit("set \"%s\" mode %04o", name, a->perm);
-                ret = chmod(name, a->perm & 07777);
-                if (ret == -1)
+        if (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) {
+                logit("set \"%s\" mode %04o", name, a.perm);
+                r = chmod(name, a.perm & 07777);
+                if (r == -1)
                         status = errno_to_portable(errno);
         }
-        if (a->flags & SSH2_FILEXFER_ATTR_ACMODTIME) {
+        if (a.flags & SSH2_FILEXFER_ATTR_ACMODTIME) {
                 char buf[64];
-                time_t t = a->mtime;
+                time_t t = a.mtime;
 
                 strftime(buf, sizeof(buf), "%Y%m%d-%H:%M:%S",
                     localtime(&t));
                 logit("set \"%s\" modtime %s", name, buf);
-                ret = utimes(name, attrib_to_tv(a));
-                if (ret == -1)
+                r = utimes(name, attrib_to_tv(&a));
+                if (r == -1)
                         status = errno_to_portable(errno);
         }
-        if (a->flags & SSH2_FILEXFER_ATTR_UIDGID) {
+        if (a.flags & SSH2_FILEXFER_ATTR_UIDGID) {
                 logit("set \"%s\" owner %lu group %lu", name,
-                    (u_long)a->uid, (u_long)a->gid);
-                ret = chown(name, a->uid, a->gid);
-                if (ret == -1)
+                    (u_long)a.uid, (u_long)a.gid);
+                r = chown(name, a.uid, a.gid);
+                if (r == -1)
                         status = errno_to_portable(errno);
         }
         send_status(id, status);
@@ -920,12 +944,14 @@ process_setstat(u_int32_t id)
 static void
 process_fsetstat(u_int32_t id)
 {
-        Attrib *a;
-        int handle, fd, ret;
+        Attrib a;
+        int handle, fd, r;
         int status = SSH2_FX_OK;
 
-        handle = get_handle();
-        a = get_attrib();
+        if ((r = get_handle(iqueue, &handle)) != 0 ||
+            (r = decode_attrib(iqueue, &a)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
         debug("request %u: fsetstat handle %d", id, handle);
         fd = handle_to_fd(handle);
         if (fd < 0)
@@ -933,47 +959,47 @@ process_fsetstat(u_int32_t id)
         else {
                 char *name = handle_to_name(handle);
 
-                if (a->flags & SSH2_FILEXFER_ATTR_SIZE) {
+                if (a.flags & SSH2_FILEXFER_ATTR_SIZE) {
                         logit("set \"%s\" size %llu",
-                            name, (unsigned long long)a->size);
-                        ret = ftruncate(fd, a->size);
-                        if (ret == -1)
+                            name, (unsigned long long)a.size);
+                        r = ftruncate(fd, a.size);
+                        if (r == -1)
                                 status = errno_to_portable(errno);
                 }
-                if (a->flags & SSH2_FILEXFER_ATTR_PERMISSIONS) {
-                        logit("set \"%s\" mode %04o", name, a->perm);
+                if (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) {
+                        logit("set \"%s\" mode %04o", name, a.perm);
 #ifdef HAVE_FCHMOD
-                        ret = fchmod(fd, a->perm & 07777);
+                        r = fchmod(fd, a.perm & 07777);
 #else
-                        ret = chmod(name, a->perm & 07777);
+                        r = chmod(name, a.perm & 07777);
 #endif
-                        if (ret == -1)
+                        if (r == -1)
                                 status = errno_to_portable(errno);
                 }
-                if (a->flags & SSH2_FILEXFER_ATTR_ACMODTIME) {
+                if (a.flags & SSH2_FILEXFER_ATTR_ACMODTIME) {
                         char buf[64];
-                        time_t t = a->mtime;
+                        time_t t = a.mtime;
 
                         strftime(buf, sizeof(buf), "%Y%m%d-%H:%M:%S",
                             localtime(&t));
                         logit("set \"%s\" modtime %s", name, buf);
 #ifdef HAVE_FUTIMES
-                        ret = futimes(fd, attrib_to_tv(a));
+                        r = futimes(fd, attrib_to_tv(&a));
 #else
-                        ret = utimes(name, attrib_to_tv(a));
+                        r = utimes(name, attrib_to_tv(&a));
 #endif
-                        if (ret == -1)
+                        if (r == -1)
                                 status = errno_to_portable(errno);
                 }
-                if (a->flags & SSH2_FILEXFER_ATTR_UIDGID) {
+                if (a.flags & SSH2_FILEXFER_ATTR_UIDGID) {
                         logit("set \"%s\" owner %lu group %lu", name,
-                            (u_long)a->uid, (u_long)a->gid);
+                            (u_long)a.uid, (u_long)a.gid);
 #ifdef HAVE_FCHOWN
-                        ret = fchown(fd, a->uid, a->gid);
+                        r = fchown(fd, a.uid, a.gid);
 #else
-                        ret = chown(name, a->uid, a->gid);
+                        r = chown(name, a.uid, a.gid);
 #endif
-                        if (ret == -1)
+                        if (r == -1)
                                 status = errno_to_portable(errno);
                 }
         }
@@ -985,9 +1011,11 @@ process_opendir(u_int32_t id)
 {
         DIR *dirp = NULL;
         char *path;
-        int handle, status = SSH2_FX_FAILURE;
+        int r, handle, status = SSH2_FX_FAILURE;
+
+        if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-        path = get_string(NULL);
         debug3("request %u: opendir", id);
         logit("opendir \"%s\"", path);
         dirp = opendir(path);
@@ -1014,9 +1042,11 @@ process_readdir(u_int32_t id)
         DIR *dirp;
         struct dirent *dp;
         char *path;
-        int handle;
+        int r, handle;
+
+        if ((r = get_handle(iqueue, &handle)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-        handle = get_handle();
         debug("request %u: readdir \"%s\" (handle %d)", id,
             handle_to_name(handle), handle);
         dirp = handle_to_dir(handle);
@@ -1025,7 +1055,7 @@ process_readdir(u_int32_t id)
                 send_status(id, SSH2_FX_FAILURE);
         } else {
                 struct stat st;
-                char pathname[MAXPATHLEN];
+                char pathname[PATH_MAX];
                 Stat *stats;
                 int nstats = 10, count = 0, i;
 
@@ -1066,14 +1096,15 @@ static void
 process_remove(u_int32_t id)
 {
         char *name;
-        int status = SSH2_FX_FAILURE;
-        int ret;
+        int r, status = SSH2_FX_FAILURE;
+
+        if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-        name = get_string(NULL);
         debug3("request %u: remove", id);
         logit("remove name \"%s\"", name);
-        ret = unlink(name);
-        status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
+        r = unlink(name);
+        status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
         send_status(id, status);
         free(name);
 }
@@ -1081,18 +1112,20 @@ process_remove(u_int32_t id)
 static void
 process_mkdir(u_int32_t id)
 {
-        Attrib *a;
+        Attrib a;
         char *name;
-        int ret, mode, status = SSH2_FX_FAILURE;
+        int r, mode, status = SSH2_FX_FAILURE;
+
+        if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
+            (r = decode_attrib(iqueue, &a)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-        name = get_string(NULL);
-        a = get_attrib();
-        mode = (a->flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ?
-            a->perm & 07777 : 0777;
+        mode = (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ?
+            a.perm & 07777 : 0777;
         debug3("request %u: mkdir", id);
         logit("mkdir name \"%s\" mode 0%o", name, mode);
-        ret = mkdir(name, mode);
-        status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
+        r = mkdir(name, mode);
+        status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
         send_status(id, status);
         free(name);
 }
@@ -1101,13 +1134,15 @@ static void
 process_rmdir(u_int32_t id)
 {
         char *name;
-        int ret, status;
+        int r, status;
+
+        if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-        name = get_string(NULL);
         debug3("request %u: rmdir", id);
         logit("rmdir name \"%s\"", name);
-        ret = rmdir(name);
-        status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
+        r = rmdir(name);
+        status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
         send_status(id, status);
         free(name);
 }
@@ -1115,10 +1150,13 @@ process_rmdir(u_int32_t id)
 static void
 process_realpath(u_int32_t id)
 {
-        char resolvedname[MAXPATHLEN];
+        char resolvedname[PATH_MAX];
         char *path;
+        int r;
+
+        if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-        path = get_string(NULL);
         if (path[0] == '\0') {
                 free(path);
                 path = xstrdup(".");
@@ -1140,11 +1178,13 @@ static void
 process_rename(u_int32_t id)
 {
         char *oldpath, *newpath;
-        int status;
+        int r, status;
         struct stat sb;
 
-        oldpath = get_string(NULL);
-        newpath = get_string(NULL);
+        if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 ||
+            (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
         debug3("request %u: rename", id);
         logit("rename old \"%s\" new \"%s\"", oldpath, newpath);
         status = SSH2_FX_FAILURE;
@@ -1197,11 +1237,13 @@ process_rename(u_int32_t id)
 static void
 process_readlink(u_int32_t id)
 {
-        int len;
-        char buf[MAXPATHLEN];
+        int r, len;
+        char buf[PATH_MAX];
         char *path;
 
-        path = get_string(NULL);
+        if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
         debug3("request %u: readlink", id);
         verbose("readlink \"%s\"", path);
         if ((len = readlink(path, buf, sizeof(buf) - 1)) == -1)
@@ -1221,15 +1263,17 @@ static void
 process_symlink(u_int32_t id)
 {
         char *oldpath, *newpath;
-        int ret, status;
+        int r, status;
+
+        if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 ||
+            (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-        oldpath = get_string(NULL);
-        newpath = get_string(NULL);
         debug3("request %u: symlink", id);
         logit("symlink old \"%s\" new \"%s\"", oldpath, newpath);
         /* this will fail if 'newpath' exists */
-        ret = symlink(oldpath, newpath);
-        status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
+        r = symlink(oldpath, newpath);
+        status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
         send_status(id, status);
         free(oldpath);
         free(newpath);
@@ -1239,14 +1283,16 @@ static void
 process_extended_posix_rename(u_int32_t id)
 {
         char *oldpath, *newpath;
-        int ret, status;
+        int r, status;
+
+        if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 ||
+            (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-        oldpath = get_string(NULL);
-        newpath = get_string(NULL);
         debug3("request %u: posix-rename", id);
         logit("posix-rename old \"%s\" new \"%s\"", oldpath, newpath);
-        ret = rename(oldpath, newpath);
-        status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
+        r = rename(oldpath, newpath);
+        status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
         send_status(id, status);
         free(oldpath);
         free(newpath);
@@ -1257,8 +1303,10 @@ process_extended_statvfs(u_int32_t id)
 {
         char *path;
         struct statvfs st;
+        int r;
 
-        path = get_string(NULL);
+        if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
         debug3("request %u: statvfs", id);
         logit("statvfs \"%s\"", path);
 
@@ -1272,10 +1320,11 @@ process_extended_statvfs(u_int32_t id)
 static void
 process_extended_fstatvfs(u_int32_t id)
 {
-        int handle, fd;
+        int r, handle, fd;
         struct statvfs st;
 
-        handle = get_handle();
+        if ((r = get_handle(iqueue, &handle)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
         debug("request %u: fstatvfs \"%s\" (handle %u)",
             id, handle_to_name(handle), handle);
         if ((fd = handle_to_fd(handle)) < 0) {
@@ -1292,14 +1341,16 @@ static void
 process_extended_hardlink(u_int32_t id)
 {
         char *oldpath, *newpath;
-        int ret, status;
+        int r, status;
+
+        if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 ||
+            (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-        oldpath = get_string(NULL);
-        newpath = get_string(NULL);
         debug3("request %u: hardlink", id);
         logit("hardlink old \"%s\" new \"%s\"", oldpath, newpath);
-        ret = link(oldpath, newpath);
-        status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
+        r = link(oldpath, newpath);
+        status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
         send_status(id, status);
         free(oldpath);
         free(newpath);
@@ -1308,16 +1359,17 @@ process_extended_hardlink(u_int32_t id)
 static void
 process_extended_fsync(u_int32_t id)
 {
-        int handle, fd, ret, status = SSH2_FX_OP_UNSUPPORTED;
+        int handle, fd, r, status = SSH2_FX_OP_UNSUPPORTED;
 
-        handle = get_handle();
+        if ((r = get_handle(iqueue, &handle)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
         debug3("request %u: fsync (handle %u)", id, handle);
         verbose("fsync \"%s\"", handle_to_name(handle));
         if ((fd = handle_to_fd(handle)) < 0)
                 status = SSH2_FX_NO_SUCH_FILE;
         else if (handle_is_ok(handle, HANDLE_FILE)) {
-                ret = fsync(fd);
-                status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
+                r = fsync(fd);
+                status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
         }
         send_status(id, status);
 }
@@ -1326,9 +1378,10 @@ static void
 process_extended(u_int32_t id)
 {
         char *request;
-        u_int i;
+        int i, r;
 
-        request = get_string(NULL);
+        if ((r = sshbuf_get_cstring(iqueue, &request, NULL)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
         for (i = 0; extended_handlers[i].handler != NULL; i++) {
                 if (strcmp(request, extended_handlers[i].ext_name) == 0) {
                         if (!request_permitted(&extended_handlers[i]))
@@ -1350,14 +1403,18 @@ process_extended(u_int32_t id)
 static void
 process(void)
 {
-        u_int msg_len, buf_len, consumed, type, i;
-        u_char *cp;
+        u_int msg_len;
+        u_int buf_len;
+        u_int consumed;
+        u_char type;
+        const u_char *cp;
+        int i, r;
         u_int32_t id;
 
-        buf_len = buffer_len(&iqueue);
+        buf_len = sshbuf_len(iqueue);
         if (buf_len < 5)
                 return;         /* Incomplete message. */
-        cp = buffer_ptr(&iqueue);
+        cp = sshbuf_ptr(iqueue);
         msg_len = get_u32(cp);
         if (msg_len > SFTP_MAX_MSG_LENGTH) {
                 error("bad message from %s local user %s",
@@ -1366,9 +1423,11 @@ process(void)
         }
         if (buf_len < msg_len + 4)
                 return;
-        buffer_consume(&iqueue, 4);
+        if ((r = sshbuf_consume(iqueue, 4)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
         buf_len -= 4;
-        type = buffer_get_char(&iqueue);
+        if ((r = sshbuf_get_u8(iqueue, &type)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
         switch (type) {
         case SSH2_FXP_INIT:
@@ -1378,13 +1437,15 @@ process(void)
         case SSH2_FXP_EXTENDED:
                 if (!init_done)
                         fatal("Received extended request before init");
-                id = get_int();
+                if ((r = sshbuf_get_u32(iqueue, &id)) != 0)
+                        fatal("%s: buffer error: %s", __func__, ssh_err(r));
                 process_extended(id);
                 break;
         default:
                 if (!init_done)
                         fatal("Received %u request before init", type);
-                id = get_int();
+                if ((r = sshbuf_get_u32(iqueue, &id)) != 0)
+                        fatal("%s: buffer error: %s", __func__, ssh_err(r));
                 for (i = 0; handlers[i].handler != NULL; i++) {
                         if (type == handlers[i].type) {
                                 if (!request_permitted(&handlers[i])) {
@@ -1400,17 +1461,18 @@ process(void)
                         error("Unknown message %u", type);
         }
         /* discard the remaining bytes from the current packet */
-        if (buf_len < buffer_len(&iqueue)) {
+        if (buf_len < sshbuf_len(iqueue)) {
                 error("iqueue grew unexpectedly");
                 sftp_server_cleanup_exit(255);
         }
-        consumed = buf_len - buffer_len(&iqueue);
+        consumed = buf_len - sshbuf_len(iqueue);
         if (msg_len < consumed) {
                 error("msg_len %u < consumed %u", msg_len, consumed);
                 sftp_server_cleanup_exit(255);
         }
-        if (msg_len > consumed)
-                buffer_consume(&iqueue, msg_len - consumed);
+        if (msg_len > consumed &&
+            (r = sshbuf_consume(iqueue, msg_len - consumed)) != 0)
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
 }
 
 /* Cleanup handler that logs active handles upon normal exit */
@@ -1443,7 +1505,7 @@ int
 sftp_server_main(int argc, char **argv, struct passwd *user_pw)
 {
         fd_set *rset, *wset;
-        int i, in, out, max, ch, skipargs = 0, log_stderr = 0;
+        int i, r, in, out, max, ch, skipargs = 0, log_stderr = 0;
         ssize_t len, olen, set_size;
         SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
         char *cp, *homedir = NULL, buf[4*4096];
@@ -1565,8 +1627,10 @@ sftp_server_main(int argc, char **argv, struct passwd *user_pw)
         if (out > max)
                 max = out;
 
-        buffer_init(&iqueue);
-        buffer_init(&oqueue);
+        if ((iqueue = sshbuf_new()) == NULL)
+                fatal("%s: sshbuf_new failed", __func__);
+        if ((oqueue = sshbuf_new()) == NULL)
+                fatal("%s: sshbuf_new failed", __func__);
 
         set_size = howmany(max + 1, NFDBITS) * sizeof(fd_mask);
         rset = (fd_set *)xmalloc(set_size);
@@ -1588,11 +1652,15 @@ sftp_server_main(int argc, char **argv, struct passwd *user_pw)
                  * the worst-case length packet it can generate,
                  * otherwise apply backpressure by stopping reads.
                  */
-                if (buffer_check_alloc(&iqueue, sizeof(buf)) &&
-                    buffer_check_alloc(&oqueue, SFTP_MAX_MSG_LENGTH))
+                if ((r = sshbuf_check_reserve(iqueue, sizeof(buf))) == 0 &&
+                    (r = sshbuf_check_reserve(oqueue,
+                    SFTP_MAX_MSG_LENGTH)) == 0)
                         FD_SET(in, rset);
+                else if (r != SSH_ERR_NO_BUFFER_SPACE)
+                        fatal("%s: sshbuf_check_reserve failed: %s",
+                            __func__, ssh_err(r));
 
-                olen = buffer_len(&oqueue);
+                olen = sshbuf_len(oqueue);
                 if (olen > 0)
                         FD_SET(out, wset);
 
@@ -1612,18 +1680,20 @@ sftp_server_main(int argc, char **argv, struct passwd *user_pw)
                         } else if (len < 0) {
                                 error("read: %s", strerror(errno));
                                 sftp_server_cleanup_exit(1);
-                        } else {
-                                buffer_append(&iqueue, buf, len);
+                        } else if ((r = sshbuf_put(iqueue, buf, len)) != 0) {
+                                fatal("%s: buffer error: %s",
+                                    __func__, ssh_err(r));
                         }
                 }
                 /* send oqueue to stdout */
                 if (FD_ISSET(out, wset)) {
-                        len = write(out, buffer_ptr(&oqueue), olen);
+                        len = write(out, sshbuf_ptr(oqueue), olen);
                         if (len < 0) {
                                 error("write: %s", strerror(errno));
                                 sftp_server_cleanup_exit(1);
-                        } else {
-                                buffer_consume(&oqueue, len);
+                        } else if ((r = sshbuf_consume(oqueue, len)) != 0) {
+                                fatal("%s: buffer error: %s",
+                                    __func__, ssh_err(r));
                         }
                 }
 
@@ -1632,7 +1702,11 @@ sftp_server_main(int argc, char **argv, struct passwd *user_pw)
                  * into the output buffer, otherwise stop processing input
                  * and let the output queue drain.
                  */
-                if (buffer_check_alloc(&oqueue, SFTP_MAX_MSG_LENGTH))
+                r = sshbuf_check_reserve(oqueue, SFTP_MAX_MSG_LENGTH);
+                if (r == 0)
                         process();
+                else if (r != SSH_ERR_NO_BUFFER_SPACE)
+                        fatal("%s: sshbuf_check_reserve: %s",
+                            __func__, ssh_err(r));
         }
 }