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-rw-r--r--lib/ssh/doc/src/Makefile3
-rw-r--r--lib/ssh/doc/src/ref_man.xml1
-rw-r--r--lib/ssh/doc/src/specs.xml1
-rw-r--r--lib/ssh/doc/src/ssh.xml72
-rw-r--r--lib/ssh/doc/src/ssh_app.xml7
-rw-r--r--lib/ssh/doc/src/ssh_file.xml275
-rw-r--r--lib/ssh/doc/src/terminology.xml185
-rw-r--r--lib/ssh/doc/src/usersguide.xml1
-rw-r--r--lib/ssh/doc/src/using_ssh.xml11
-rw-r--r--lib/ssh/src/ssh.hrl14
-rw-r--r--lib/ssh/src/ssh_file.erl17
11 files changed, 520 insertions, 67 deletions
diff --git a/lib/ssh/doc/src/Makefile b/lib/ssh/doc/src/Makefile
index 77fa356092..4e32dd9976 100644
--- a/lib/ssh/doc/src/Makefile
+++ b/lib/ssh/doc/src/Makefile
@@ -45,6 +45,7 @@ XML_REF3_FILES = \
ssh_connection.xml \
ssh_server_channel.xml \
ssh_server_key_api.xml \
+ ssh_file.xml \
ssh_sftp.xml \
ssh_sftpd.xml \
@@ -56,8 +57,8 @@ XML_CHAPTER_FILES = \
notes.xml \
introduction.xml \
using_ssh.xml \
+ terminology.xml \
configure_algos.xml
-# ssh_protocol.xml \
BOOK_FILES = book.xml
diff --git a/lib/ssh/doc/src/ref_man.xml b/lib/ssh/doc/src/ref_man.xml
index df37b0244f..60572b985b 100644
--- a/lib/ssh/doc/src/ref_man.xml
+++ b/lib/ssh/doc/src/ref_man.xml
@@ -40,6 +40,7 @@
<xi:include href="ssh_connection.xml"/>
<xi:include href="ssh_client_key_api.xml"/>
<xi:include href="ssh_server_key_api.xml"/>
+ <xi:include href="ssh_file.xml"/>
<xi:include href="ssh_sftp.xml"/>
<xi:include href="ssh_sftpd.xml"/>
</application>
diff --git a/lib/ssh/doc/src/specs.xml b/lib/ssh/doc/src/specs.xml
index acdbe2ddfd..a6517f3660 100644
--- a/lib/ssh/doc/src/specs.xml
+++ b/lib/ssh/doc/src/specs.xml
@@ -6,6 +6,7 @@
<xi:include href="../specs/specs_ssh_connection.xml"/>
<xi:include href="../specs/specs_ssh_server_channel.xml"/>
<xi:include href="../specs/specs_ssh_server_key_api.xml"/>
+ <xi:include href="../specs/specs_ssh_file.xml"/>
<xi:include href="../specs/specs_ssh_sftp.xml"/>
<xi:include href="../specs/specs_ssh_sftpd.xml"/>
</specs>
diff --git a/lib/ssh/doc/src/ssh.xml b/lib/ssh/doc/src/ssh.xml
index 3bc62073a2..93e52ce023 100644
--- a/lib/ssh/doc/src/ssh.xml
+++ b/lib/ssh/doc/src/ssh.xml
@@ -99,8 +99,8 @@
</p>
<p>The paths could easily be changed by options:
- <seealso marker="#type-user_dir_common_option"><c>user_dir</c></seealso> and
- <seealso marker="#type-system_dir_daemon_option"><c>system_dir</c></seealso>.
+ <seealso marker="ssh_file#type-user_dir_common_option"><c>user_dir</c></seealso> and
+ <seealso marker="ssh_file#type-system_dir_daemon_option"><c>system_dir</c></seealso>.
</p>
<p>A completly different storage could be interfaced by writing call-back modules
using the behaviours
@@ -123,12 +123,12 @@
<item><c>ssh_host_ecdsa_key</c> and <c>ssh_host_ecdsa_key.pub</c></item>
</list>
<p>The host keys directory could be changed with the option
- <seealso marker="#type-system_dir_daemon_option"><c>system_dir</c></seealso>.</p>
+ <seealso marker="ssh_file#type-system_dir_daemon_option"><c>system_dir</c></seealso>.</p>
</item>
<item>Optional: one or more <i>User's public key</i> in case of <c>publickey</c> authorization.
Default is to store them concatenated in the file <c>.ssh/authorized_keys</c> in the user's home directory.
<p>The user keys directory could be changed with the option
- <seealso marker="#type-user_dir_common_option"><c>user_dir</c></seealso>.</p>
+ <seealso marker="ssh_file#type-user_dir_common_option"><c>user_dir</c></seealso>.</p>
</item>
</list>
</section>
@@ -138,7 +138,7 @@
<p>The keys and some other data are by default stored in files in the directory <c>.ssh</c>
in the user's home directory.</p>
<p>The directory could be changed with the option
- <seealso marker="#type-user_dir_common_option"><c>user_dir</c></seealso>.
+ <seealso marker="ssh_file#type-user_dir_common_option"><c>user_dir</c></seealso>.
</p>
<list>
<item>Optional: a list of <i>Host public key(s)</i> for previously connected hosts. This list
@@ -192,22 +192,13 @@
<p>If there is no public key of a specified type available, the corresponding entry is ignored.
Note that the available set is dependent on the underlying cryptolib and current user's public keys.
</p>
- <p>See also the option <seealso marker="#type-user_dir_common_option"><c>user_dir</c></seealso>
+ <p>See also the option <seealso marker="ssh_file#type-user_dir_common_option"><c>user_dir</c></seealso>
for specifying the path to the user's keys.
</p>
</desc>
</datatype>
<datatype>
- <name name="pubkey_passphrase_client_options"/>
- <desc>
- <p>If the user's DSA, RSA or ECDSA key is protected by a passphrase, it can be
- supplied with thoose options.
- </p>
- </desc>
- </datatype>
-
- <datatype>
<name name="host_accepting_client_options"/>
<name name="accept_hosts"/>
<name name="fp_digest_alg"/>
@@ -220,7 +211,7 @@
<p>This option guides the <c>connect</c> function on how to act when the connected server presents a Host
Key that the client has not seen before. The default is to ask the user with a question on stdio of whether to
accept or reject the new Host Key.
- See the option <seealso marker="#type-user_dir_common_option"><c>user_dir</c></seealso>
+ See the option <seealso marker="ssh_file#type-user_dir_common_option"><c>user_dir</c></seealso>
for specifying the path to the file <c>known_hosts</c> where previously accepted Host Keys are recorded.
See also the option
<seealso marker="#type-key_cb_common_option">key_cb</seealso>
@@ -276,7 +267,7 @@
accept question the next time the same host is connected. If the option
<seealso marker="#type-key_cb_common_option"><c>key_cb</c></seealso>
is not present, the key is saved in the file "known_hosts". See option
- <seealso marker="#type-user_dir_common_option"><c>user_dir</c></seealso> for
+ <seealso marker="ssh_file#type-user_dir_common_option"><c>user_dir</c></seealso> for
the location of that file.
</p>
<p>If <c>false</c>, the key is not saved and the key will still be unknown
@@ -478,18 +469,6 @@
<name name="pwdfun_4"/>
<desc>
<taglist>
- <tag><marker id="type-system_dir_daemon_option"/><c>system_dir</c></tag>
- <item>
- <p>Sets the system directory, containing the host key files
- that identify the host keys for <c>ssh</c>. Defaults to
- <c>/etc/ssh</c>.</p>
- <p>For security reasons, this directory is normally accessible only to the root user.</p>
- <p>See also the option
- <seealso marker="#type-key_cb_common_option">key_cb</seealso>
- for the general way to handle keys.
- </p>
- </item>
-
<tag><c>auth_method_kb_interactive_data</c></tag>
<item>
<p>Sets the text strings that the daemon sends to the client for presentation to the user when
@@ -502,7 +481,7 @@
</p>
</item>
- <tag><c>user_passwords</c></tag>
+ <tag><marker id="option-user_passwords"/><c>user_passwords</c></tag>
<item>
<p>Provides passwords for password authentication. The passwords are used when someone tries
to connect to the server and public key user-authentication fails. The option provides
@@ -510,7 +489,7 @@
</p>
</item>
- <tag><c>password</c></tag>
+ <tag><marker id="option-password"/><c>password</c></tag>
<item>
<p>Provides a global password that authenticates any user.</p>
<warning>
@@ -519,7 +498,9 @@
</warning>
</item>
- <tag><c>pwdfun</c> with <c>pwdfun_4()</c></tag>
+ <tag><marker id="option-pwdfun"/><c>pwdfun</c> with
+ <seealso marker="#type-pwdfun_4"><c>pwdfun_4()</c></seealso>
+ </tag>
<item>
<p>Provides a function for password validation. This could used for calling an external system or handeling
passwords stored as hash values.
@@ -546,7 +527,9 @@
can be used for this. The return value <c>disconnect</c> is useful for this.</p>
</item>
- <tag><c>pwdfun</c> with <c>pwdfun_2()</c></tag>
+ <tag><c>pwdfun</c> with
+ <seealso marker="#type-pwdfun_2"><c>pwdfun_2()</c></seealso>
+ </tag>
<item>
<p>Provides a function for password validation. This function is called with user and password
as strings, and returns:</p>
@@ -725,21 +708,6 @@
</datatype>
<datatype>
- <name name="user_dir_common_option"/>
- <desc>
- <p>Sets the user directory. That is, the directory containing <c>ssh</c> configuration
- files for the user, such as
- <c>known_hosts</c>, <c>id_rsa</c>, <c>id_dsa</c>>, <c>id_ecdsa</c> and <c>authorized_key</c>.
- Defaults to the directory normally referred to as <c>~/.ssh</c>.
- </p>
- <p>See also the option
- <seealso marker="#type-key_cb_common_option">key_cb</seealso>
- for the general way to handle keys.
- </p>
- </desc>
- </datatype>
-
- <datatype>
<name name="profile_common_option"/>
<desc>
<p>Used together with <c>ip-address</c> and <c>port</c> to
@@ -795,7 +763,8 @@
</p>
<p>The <c>Opts</c> defaults to <c>[]</c> when only the <c>Module</c> is specified.
</p>
- <p>The default value of this option is <c>{ssh_file, []}</c>.
+ <p>The default value of this option is <c>{ssh_file, []}</c>. See also the manpage of
+ <seealso marker="ssh:ssh_file">ssh_file</seealso>.
</p>
<p>A call to the call-back function <c>F</c> will be</p>
<code>
@@ -804,7 +773,10 @@
<p>where <c>...</c> are arguments to <c>F</c> as in
<seealso marker="ssh_client_key_api">ssh_client_key_api</seealso> and/or
<seealso marker="ssh_server_key_api">ssh_server_key_api</seealso>.
- The <c>UserOptions</c> are the options given to <c>ssh:connect</c>, <c>ssh:shell</c> or <c>ssh:daemon</c>.
+ The <c>UserOptions</c> are the options given to
+ <seealso marker="ssh:ssh#connect-3">ssh:connect</seealso>,
+ <seealso marker="ssh:ssh#shell-1">ssh:shell</seealso> or
+ <seealso marker="ssh:ssh#daemon-2">ssh:daemon</seealso>.
</p>
</desc>
diff --git a/lib/ssh/doc/src/ssh_app.xml b/lib/ssh/doc/src/ssh_app.xml
index e80bb1853d..eb804e67dc 100644
--- a/lib/ssh/doc/src/ssh_app.xml
+++ b/lib/ssh/doc/src/ssh_app.xml
@@ -74,13 +74,18 @@
<c>id_ecdsa_key</c>,
<c>known_hosts</c>, and <c>authorized_keys</c> in ~/.ssh,
and for the host key files in <c>/etc/ssh</c>. These locations can be changed
- by the options <c>user_dir</c> and <c>system_dir</c>.
+ by the options
+ <seealso marker="ssh_file#type-user_dir_common_option"><c>user_dir</c></seealso> and
+ <seealso marker="ssh_file#type-system_dir_daemon_option"><c>system_dir</c></seealso>.
</p>
<p>Public key handling can also be customized through a callback module that
implements the behaviors
<seealso marker="ssh_client_key_api">ssh_client_key_api</seealso> and
<seealso marker="ssh_server_key_api">ssh_server_key_api</seealso>.
</p>
+ <p>See also the default callback module documentation in
+ <seealso marker="ssh_file">ssh_file</seealso>.
+ </p>
</section>
<section>
diff --git a/lib/ssh/doc/src/ssh_file.xml b/lib/ssh/doc/src/ssh_file.xml
new file mode 100644
index 0000000000..ae6ba2e1d9
--- /dev/null
+++ b/lib/ssh/doc/src/ssh_file.xml
@@ -0,0 +1,275 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<!DOCTYPE erlref SYSTEM "erlref.dtd">
+
+<erlref>
+ <header>
+ <copyright>
+ <year>2018</year><year>2018</year>
+ <holder>Ericsson AB. All Rights Reserved.</holder>
+ </copyright>
+ <legalnotice>
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+
+ </legalnotice>
+
+ <title>ssh_file</title>
+ <prepared></prepared>
+ <docno></docno>
+ <date></date>
+ <rev></rev>
+ </header>
+ <module>ssh_file</module>
+ <modulesummary>Default callback module for the client's and server's database operations in the ssh application</modulesummary>
+ <description>
+ <p>This module is the default callback handler for the client's and the server's user and host "database" operations.
+ All data, for instance key pairs, are stored in files in the normal file system. This page documents the files, where they
+ are stored and configuration options for this callback module.
+ </p>
+ <p>The intention is to be compatible with the
+ <url href="http://www.openssh.com">OpenSSH</url>
+ storage in files. Therefore it mimics directories and filenames of
+ <url href="http://www.openssh.com">OpenSSH</url>.
+ </p>
+
+ <p>Ssh_file implements the <seealso marker="ssh:ssh_server_key_api">ssh_server_key_api</seealso> and
+ the <seealso marker="ssh:ssh_client_key_api">ssh_client_key_api</seealso>.
+ This enables the user to make an own interface using for example a database handler.
+ </p>
+ <p>Such another callback module could be used by setting the option
+ <seealso marker="ssh:ssh#type-key_cb_common_option"><c>key_cb</c></seealso>
+ when starting a client or a server (with for example
+ <seealso marker="ssh:ssh#connect-3">ssh:connect</seealso>,
+ <seealso marker="ssh:ssh#daemon-2">ssh:daemon</seealso> of
+ <seealso marker="ssh:ssh#shell-1">ssh:shell</seealso>
+ ).
+ </p>
+
+ <note>
+ <p>The functions are <i>Callbacks</i> for the SSH app. They are not intended to be called from the user's code!
+ </p>
+ </note>
+ </description>
+
+ <section>
+ <title>Files, directories and who uses them</title>
+ <section>
+ <title>Daemons</title>
+ <p>Daemons uses all files stored in the <seealso marker="#SYSDIR">SYSDIR</seealso> directory.
+ </p>
+ <p>Optionaly, in case of <c>publickey</c> authorization, one or more of the remote user's public keys
+ in the <seealso marker="#USERDIR">USERDIR</seealso> directory are used.
+ See the files
+ <seealso marker="#USERDIR-authorized_keys"><c>USERDIR/authorized_keys</c></seealso> and
+ <seealso marker="#USERDIR-authorized_keys2"><c>USERDIR/authorized_keys2</c></seealso>.
+ </p>
+ </section>
+
+ <section>
+ <title>Clients</title>
+ <p>Clients uses all files stored in the <seealso marker="#USERDIR">USERDIR</seealso> directory.
+ </p>
+ </section>
+
+ <section>
+ <title>Directory contents</title>
+ <taglist>
+ <tag><marker id="LOCALUSER"/>LOCALUSER</tag>
+ <item><p>The user name of the OS process running the Erlang virtual machine (emulator).</p>
+ </item>
+
+ <tag><marker id="SYSDIR"/>SYSDIR</tag>
+ <item><p>This is the directory holding the server's files:</p>
+ <list>
+ <item><marker id="SYSDIR-ssh_host_dsa_key"/><c>ssh_host_dsa_key</c> - private dss host key (optional)</item>
+ <item><marker id="SYSDIR-ssh_host_rsa_key"/><c>ssh_host_rsa_key</c> - private rsa host key (optional)</item>
+ <item><marker id="SYSDIR-ssh_host_ecdsa_key"/><c>ssh_host_ecdsa_key</c> - private ecdsa host key (optional)</item>
+ </list>
+ <p>At least one host key must be defined. The default value of SYSDIR is <marker id="#/etc/ssh"/><c>/etc/ssh</c>.
+ </p>
+ <p>For security reasons, this directory is normally accessible only to the root user.
+ </p>
+ <p>To change the SYSDIR, see the <seealso marker="#type-system_dir_daemon_option">system_dir</seealso> option.
+ </p>
+ </item>
+
+ <tag><marker id="USERDIR"/>USERDIR</tag>
+ <item><p>This is the directory holding the files:</p>
+ <list>
+ <item><marker id="USERDIR-authorized_keys"/><c>authorized_keys</c>
+ and, as second alternative
+ <marker id="USERDIR-authorized_keys2"/><c>authorized_keys2</c> -
+ the user's public keys are stored concatenated in one of those files.
+ </item>
+ <item><marker id="USERDIR-known_hosts"/><c>known_hosts</c> - host keys from hosts visited
+ concatenated. The file is created and used by the client.</item>
+ <item><marker id="USERDIR-id_dsa"/><c>id_dsa</c> - private dss user key (optional)</item>
+ <item><marker id="USERDIR-id_rsa"/><c>id_rsa</c> - private rsa user key (optional)</item>
+ <item><marker id="USERDIR-id_ecdsa"/><c>id_ecdsa</c> - private ecdsa user key (optional)</item>
+ </list>
+ <p>The default value of USERDIR is <c>/home/</c><seealso marker="#LOCALUSER"><c>LOCALUSER</c></seealso><c>/.ssh</c>.
+ </p>
+ <p>To change the USERDIR, see the <seealso marker="#type-user_dir_common_option">user_dir</seealso> option
+ </p>
+ </item>
+ </taglist>
+ </section>
+ </section>
+
+ <datatypes>
+ <datatype_title>Options for the default ssh_file callback module</datatype_title>
+ <datatype>
+ <name name="user_dir_common_option"/>
+ <desc>
+ <p>Sets the <seealso marker="#USERDIR">user directory</seealso>.</p>
+ </desc>
+ </datatype>
+
+ <datatype>
+ <name name="user_dir_fun_common_option"/>
+ <name name="user2dir"/>
+ <desc>
+ <p>Sets the <seealso marker="#USERDIR">user directory</seealso> dynamically
+ by evaluating the <c>user2dir</c> function.
+ </p>
+ </desc>
+ </datatype>
+
+ <datatype>
+ <name name="system_dir_daemon_option"/>
+ <desc>
+ <p>Sets the <seealso marker="#SYSDIR">system directory</seealso>.</p>
+ </desc>
+ </datatype>
+
+ <datatype>
+ <name name="pubkey_passphrase_client_options"/>
+ <desc>
+ <p>If the user's DSA, RSA or ECDSA key is protected by a passphrase, it can be
+ supplied with thoose options.
+ </p>
+ </desc>
+ </datatype>
+
+ </datatypes>
+
+ <funcs>
+ <func>
+ <name>host_key(Algorithm, DaemonOptions) -> {ok, Key} | {error, Reason}</name>
+ <fsummary></fsummary>
+ <desc>
+ <p><strong>Types and description</strong></p>
+ <p>See the api description in
+ <seealso marker="ssh:ssh_server_key_api#Module:host_key-2">ssh_server_key_api, Module:host_key/2</seealso>.
+ </p>
+ <p><strong>Options</strong></p>
+ <list>
+ <item><seealso marker="#type-system_dir_daemon_option">system_dir</seealso></item>
+ <!-- item>dsa_pass_phrase</item -->
+ <!-- item>rsa_pass_phrase</item -->
+ <!-- item>ecdsa_pass_phrase</item -->
+ </list>
+ <p><strong>Files</strong></p>
+ <list>
+ <item><seealso marker="#SYSDIR-ssh_host_rsa_key"><c>SYSDIR/ssh_host_rsa_key</c></seealso></item>
+ <item><seealso marker="#SYSDIR-ssh_host_dsa_key"><c>SYSDIR/ssh_host_dsa_key</c></seealso></item>
+ <item><seealso marker="#SYSDIR-ssh_host_ecdsa_key"><c>SYSDIR/ssh_host_ecdsa_key</c></seealso></item>
+ </list>
+ </desc>
+ </func>
+
+ <func>
+ <name>is_auth_key(PublicUserKey, User, DaemonOptions) -> Result</name>
+ <fsummary></fsummary>
+ <desc>
+ <p><strong>Types and description</strong></p>
+ <p>See the api description in
+ <seealso marker="ssh:ssh_server_key_api#Module:is_auth_key-3">ssh_server_key_api: Module:is_auth_key/3</seealso>.
+ </p>
+ <p><strong>Options</strong></p>
+ <list>
+ <item><seealso marker="#type-user_dir_fun_common_option">user_dir_fun</seealso></item>
+ <item><seealso marker="#type-user_dir_common_option">user_dir</seealso></item>
+ </list>
+ <p><strong>Files</strong></p>
+ <list>
+ <item><seealso marker="#USERDIR-authorized_keys"><c>USERDIR/authorized_keys</c></seealso></item>
+ <item><seealso marker="#USERDIR-authorized_keys2"><c>USERDIR/authorized_keys2</c></seealso></item>
+ </list>
+ </desc>
+ </func>
+
+ <func>
+ <name>add_host_key(HostNames, PublicHostKey, ConnectOptions) -> ok | {error, Reason}</name>
+ <fsummary></fsummary>
+ <desc>
+ <p><strong>Types and description</strong></p>
+ <p>See the api description in
+ <seealso marker="ssh:ssh_client_key_api#Module:add_host_key-3">ssh_client_key_api, Module:add_host_key/3</seealso>.
+ </p>
+ <p><strong>Option</strong></p>
+ <list>
+ <item><seealso marker="#type-user_dir_common_option">user_dir</seealso></item>
+ </list>
+ <p><strong>File</strong></p>
+ <list>
+ <item><seealso marker="#USERDIR-known_hosts"><c>USERDIR/known_hosts</c></seealso></item>
+ </list>
+ </desc>
+ </func>
+
+ <func>
+ <name>is_host_key(Key, Host, Algorithm, ConnectOptions) -> Result</name>
+ <fsummary></fsummary>
+ <desc>
+ <p><strong>Types and description</strong></p>
+ <p>See the api description in
+ <seealso marker="ssh:ssh_client_key_api#Module:is_host_key-4">ssh_client_key_api, Module:is_host_key/4</seealso>.
+ </p>
+ <p><strong>Option</strong></p>
+ <list>
+ <item><seealso marker="#type-user_dir_common_option">user_dir</seealso></item>
+ </list>
+ <p><strong>File</strong></p>
+ <list>
+ <item><seealso marker="#USERDIR-known_hosts"><c>USERDIR/known_hosts</c></seealso></item>
+ </list>
+ </desc>
+ </func>
+
+ <func>
+ <name>user_key(Algorithm, ConnectOptions) -> {ok, PrivateKey} | {error, Reason}</name>
+ <fsummary></fsummary>
+ <desc>
+ <p><strong>Types and description</strong></p>
+ <p>See the api description in
+ <seealso marker="ssh:ssh_client_key_api#Module:user_key-2">ssh_client_key_api, Module:user_key/2</seealso>.
+ </p>
+ <p><strong>Options</strong></p>
+ <list>
+ <item><seealso marker="#type-user_dir_common_option">user_dir</seealso></item>
+ <item><seealso marker="#type-pubkey_passphrase_client_options">dsa_pass_phrase</seealso></item>
+ <item><seealso marker="#type-pubkey_passphrase_client_options">rsa_pass_phrase</seealso></item>
+ <item><seealso marker="#type-pubkey_passphrase_client_options">ecdsa_pass_phrase</seealso></item>
+ </list>
+ <p><strong>Files</strong></p>
+ <list>
+ <item><seealso marker="#USERDIR-id_dsa"><c>USERDIR/id_dsa</c></seealso></item>
+ <item><seealso marker="#USERDIR-id_rsa"><c>USERDIR/id_rsa</c></seealso></item>
+ <item><seealso marker="#USERDIR-id_ecdsa"><c>USERDIR/id_ecdsa</c></seealso></item>
+ </list>
+ </desc>
+ </func>
+
+ </funcs>
+
+</erlref>
diff --git a/lib/ssh/doc/src/terminology.xml b/lib/ssh/doc/src/terminology.xml
new file mode 100644
index 0000000000..db1e08970d
--- /dev/null
+++ b/lib/ssh/doc/src/terminology.xml
@@ -0,0 +1,185 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<!DOCTYPE chapter SYSTEM "chapter.dtd">
+
+<chapter>
+ <header>
+ <copyright>
+ <year>2018</year>
+ <year>2018</year>
+ <holder>Ericsson AB. All Rights Reserved.</holder>
+ </copyright>
+ <legalnotice>
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+
+ </legalnotice>
+
+ <title>Terminology</title>
+ <prepared></prepared>
+ <docno></docno>
+ <approved></approved>
+ <date></date>
+ <rev></rev>
+ <file>terminology.xml</file>
+ </header>
+
+ <section>
+ <title>General Information</title>
+ <p>In the following terms that may cause confusion are explained.
+ </p>
+ </section>
+
+ <section>
+ <title>The term "user"</title>
+ <p>A "user" is a term that everyone understands intuitively. However, the understandings may differ which can
+ cause confusion.
+ </p>
+ <p>The term is used differently in <url href="http://www.openssh.com">OpenSSH</url> and SSH in Erlang/OTP.
+ The reason is the different environments and use cases that are not immediatly obvious.
+ </p>
+ <p>This chapter aims at explaining the differences and giving a rationale for why Erlang/OTP handles "user" as
+ it does.
+ </p>
+
+ <section>
+ <title>In OpenSSH</title>
+ <p>Many have been in contact with the command 'ssh' on a Linux machine (or similar) to remotly log in on
+ another machine. One types
+ </p>
+ <code>ssh host</code>
+ <p>to log in on the machine named <c>host</c>. The command prompts for your password on the remote <c>host</c> and
+ then you can read, write and execute as your <i>user name</i> has rights on the remote <c>host</c>. There are
+ stronger variants with pre-distributed keys or certificates, but that are for now just details in the
+ authentication process.
+ </p>
+ <p>You could log in as the user <c>anotheruser</c> with
+ </p>
+ <code>ssh anotheruser@host</code>
+ <p>and you will then be enabled to act as <c>anotheruser</c> on the <c>host</c> if authorized correctly.
+ </p>
+ <p>So what does <i>"your user name has rights"</i> mean? In a UNIX/Linux/etc context it is exactly as that context:
+ The <i>user</i> could read, write and execute programs according to the OS rules.
+ In addition, the user has a home directory (<c>$HOME</c>) and there is a <c>$HOME/.ssh/</c> directory
+ with ssh-specific files.
+ </p>
+ <section>
+ <title>SSH password authentication</title>
+ <p>When SSH tries to log in to a host, the ssh protocol communicates the user name (as a string) and a password.
+ The remote ssh server checks that there is such a user defined and that the provided password is acceptable.
+ </p>
+ <p>If so, the user is authorized.
+ </p>
+ </section>
+ <section>
+ <title>SSH public key authentication</title>
+ <p>This is a stronger method where the ssh protocol brings the user name, the user's public key and some
+ cryptographic information which we could ignore here.
+ </p>
+ <p>The ssh server on the remote host checks:
+ </p>
+ <list>
+ <item>That the <i>user</i> has a home directory,</item>
+ <item>that home directory contains a .ssh/ directory and</item>
+ <item>the .ssh/ directory contains the public key just received in the <c>authorized_keys</c> file</item>
+ </list>
+ <p>if so, the user is authorized.
+ </p>
+ </section>
+ <section>
+ <title>The SSH server on UNIX/Linux/etc after a succesful authentication</title>
+ <p>After a succesful incoming authentication, a new process runs as the just authenticated user.</p>
+ <p>Next step is to start a service according to the ssh request. In case of a request of a shell,
+ a new one is started which handles the OS-commands that arrives from the client (that's "you").
+ </p>
+ <p>In case of a sftp request, an sftp server is started in with the user's rights. So it could read, write or delete
+ files if allowed for that user.
+ </p>
+ </section>
+ </section>
+
+ <section>
+ <title>In Erlang/OTP SSH</title>
+ <p>For the Erlang/OTP SSH server the situation is different. The server executes in an Erlang process
+ in the Erlang emulator which in turn executes in an OS process. The emulator does not try to change its
+ user when authenticated over the SSH protocol.
+ So the remote user name is only for authentication purposes in the Erlang/OTP SSH application.
+ </p>
+ <section>
+ <title>Password authentication in Erlang SSH</title>
+ <p>The Erlang/OTP SSH server checks the user name and password in the following order:
+ </p>
+ <list type="ordered">
+ <item>If a
+ <seealso marker="ssh:ssh#option-pwdfun"><c>pwdfun</c></seealso>
+ is defined, that one is called and the returned boolean is the authentication result.
+ </item>
+ <item>Else, if the
+ <seealso marker="ssh:ssh#option-user_passwords"><c>user_passwords</c></seealso>
+ option is defined and the username and the password matches, the authentication is a success.
+ </item>
+ <item>Else, if the option
+ <seealso marker="ssh:ssh#option-password"><c>password</c></seealso>
+ is defined and matches the password the authentication is a success.
+ Note that the use of this option is not recommended in non-test code.
+ </item>
+ </list>
+ </section>
+ <section>
+ <title>Public key authentication in Erlang SSH</title>
+ <p>The user name, public key and cryptographic data (a signature) that is sent by the client, are used as follows
+ (some steps left out for clearity):
+ </p>
+ <list type="ordered">
+ <item>A callback module is selected using the options
+ <seealso marker="ssh:ssh#type-key_cb_common_option"><c>key_cb</c></seealso>.
+ </item>
+ <item>The callback module is used to check that the provided public key is one of the user's pre-stored.
+ In case of the default callback module, the files <c>authorized_keys</c> and <c>authorized_keys2</c>
+ are searched in a directory found in the following order:
+ <list>
+ <item>If the option
+ <seealso marker="ssh:ssh_file#type-user_dir_fun_common_option"><c>user_dir_fun</c></seealso>
+ is defined, that fun is called and the returned directory is used,
+ </item>
+ <item>Else, If the option
+ <seealso marker="ssh:ssh_file#type-user_dir_common_option"><c>user_dir</c></seealso>
+ is defined, that directory is used,
+ </item>
+ <item>Else the subdirectory <c>.ssh</c> in the home directory of the user executing
+ the OS process of the Erlang emulator is used.
+ </item>
+ </list>
+ If the provided public key is not found, the authentication fails.
+ </item>
+ <item>Finally, if the provided public key is found, the signature provided by the client is checked with
+ the public key.
+ </item>
+ </list>
+ </section>
+ <section>
+ <title>The Erlang/OTP SSH server after a succesful authentication</title>
+ <p>After a successful authentication an <i>Erlang process</i> is handling the service request from the remote
+ ssh client. The rights of that process are those of the user of the OS process running the Erlang emulator.
+ </p>
+ <p>If a shell service request arrives to the server, an <i>Erlang shell</i> is opened in the server's emulator.
+ The rights in that shell is independent of the just authenticated user.
+ </p>
+ <p>In case of an sftp request, an sftp server is started with the rights of the user of the Erlang emulator's OS
+ process. So with sftp the authenticated user does not influence the rights.
+ </p>
+ <p>So after an authentication, the user name is not used anymore and has no influence.
+ </p>
+ </section>
+ </section>
+ </section>
+</chapter>
+
diff --git a/lib/ssh/doc/src/usersguide.xml b/lib/ssh/doc/src/usersguide.xml
index 38ffa48cde..8a4df208d8 100644
--- a/lib/ssh/doc/src/usersguide.xml
+++ b/lib/ssh/doc/src/usersguide.xml
@@ -36,5 +36,6 @@
</description>
<xi:include href="introduction.xml"/>
<xi:include href="using_ssh.xml"/>
+ <xi:include href="terminology.xml"/>
<xi:include href="configure_algos.xml"/>
</part>
diff --git a/lib/ssh/doc/src/using_ssh.xml b/lib/ssh/doc/src/using_ssh.xml
index 80662e9a70..4455d5ecc5 100644
--- a/lib/ssh/doc/src/using_ssh.xml
+++ b/lib/ssh/doc/src/using_ssh.xml
@@ -74,16 +74,17 @@
<marker id="Running an Erlang ssh Daemon"></marker>
<title>Running an Erlang ssh Daemon</title>
- <p>The <c>system_dir</c> option must be a directory containing a host
- key file and it defaults to <c>/etc/ssh</c>. For details, see Section
- Configuration Files in <seealso
- marker="SSH_app">ssh(6)</seealso>.
+ <p>The
+ <seealso marker="ssh_file#type-system_dir_daemon_option"><c>system_dir</c></seealso>
+ option must be a directory containing a host key file and it defaults to <c>/etc/ssh</c>.
+ For details, see Section Configuration Files in <seealso marker="SSH_app">ssh(6)</seealso>.
</p>
<note><p>Normally, the <c>/etc/ssh</c> directory is only readable by root.</p>
</note>
- <p>The option <c>user_dir</c> defaults to directory <c>users ~/.ssh</c>.</p>
+ <p>The option <seealso marker="ssh_file#type-user_dir_common_option"><c>user_dir</c></seealso>
+ defaults to directory <c>users ~/.ssh</c>.</p>
<p><em>Step 1.</em> To run the example without root privileges,
generate new keys and host keys:</p>
diff --git a/lib/ssh/src/ssh.hrl b/lib/ssh/src/ssh.hrl
index 94b9f3a196..3ac74c4925 100644
--- a/lib/ssh/src/ssh.hrl
+++ b/lib/ssh/src/ssh.hrl
@@ -173,7 +173,7 @@
-type common_options() :: [ common_option() ].
-type common_option() ::
- user_dir_common_option()
+ ssh_file:user_dir_common_option()
| profile_common_option()
| max_idle_time_common_option()
| key_cb_common_option()
@@ -191,8 +191,6 @@
-define(COMMON_OPTION, common_option()).
-
--type user_dir_common_option() :: {user_dir, false | string()}.
-type profile_common_option() :: {profile, atom() }.
-type max_idle_time_common_option() :: {idle_time, timeout()}.
-type rekey_limit_common_option() :: {rekey_limit, Bytes::limit_bytes() |
@@ -223,14 +221,14 @@
{transport, {atom(),atom(),atom()} }
| {vsn, {non_neg_integer(),non_neg_integer()} }
| {tstflg, list(term())}
- | {user_dir_fun, fun()}
+ | ssh_file:user_dir_fun_common_option()
| {max_random_length_padding, non_neg_integer()} .
-type client_option() ::
pref_public_key_algs_client_option()
- | pubkey_passphrase_client_options()
+ | ssh_file:pubkey_passphrase_client_options()
| host_accepting_client_options()
| authentication_client_options()
| diffie_hellman_group_exchange_client_option()
@@ -246,10 +244,6 @@
-type pref_public_key_algs_client_option() :: {pref_public_key_algs, [pubkey_alg()] } .
--type pubkey_passphrase_client_options() :: {dsa_pass_phrase, string()}
- | {rsa_pass_phrase, string()}
- | {ecdsa_pass_phrase, string()} .
-
-type host_accepting_client_options() ::
{silently_accept_hosts, accept_hosts()}
| {user_interaction, boolean()}
@@ -311,7 +305,7 @@
-type send_ext_info_daemon_option() :: {send_ext_info, boolean()} .
-type authentication_daemon_options() ::
- {system_dir, string()}
+ ssh_file:system_dir_daemon_option()
| {auth_method_kb_interactive_data, prompt_texts() }
| {user_passwords, [{UserName::string(),Pwd::string()}]}
| {password, string()}
diff --git a/lib/ssh/src/ssh_file.erl b/lib/ssh/src/ssh_file.erl
index 832952ed52..669b0f9be2 100644
--- a/lib/ssh/src/ssh_file.erl
+++ b/lib/ssh/src/ssh_file.erl
@@ -39,6 +39,23 @@
is_auth_key/3]).
+-export_type([system_dir_daemon_option/0,
+ user_dir_common_option/0,
+ user_dir_fun_common_option/0,
+ pubkey_passphrase_client_options/0
+ ]).
+
+-type system_dir_daemon_option() :: {system_dir, string()}.
+-type user_dir_common_option() :: {user_dir, string()}.
+-type user_dir_fun_common_option() :: {user_dir_fun, user2dir()}.
+-type user2dir() :: fun((RemoteUserName::string()) -> UserDir :: string()) .
+
+-type pubkey_passphrase_client_options() :: {dsa_pass_phrase, string()}
+ | {rsa_pass_phrase, string()}
+ | {ecdsa_pass_phrase, string()} .
+
+
+
-define(PERM_700, 8#700).
-define(PERM_644, 8#644).