From 95924615ab42529e4dc7b95da1115346bf607fc6 Mon Sep 17 00:00:00 2001

From: Jeremy Lin <jjlin@cs.stanford.edu>

Date: Mon, 15 Sep 2014 21:16:46 -0700

Subject: [PATCH 1/2] ssh: improve key file search

For private keys, use the first match from: user-specified key file

(if provided), ~/.ssh/id_rsa, ~/.ssh/id_dsa, ./id_rsa, ./id_dsa

Note that the previous code only looked for id_dsa files. id_rsa is

now generally preferred, as it supports larger key sizes.

For public keys, use the user-specified key file, if provided.

Otherwise, try to extract the public key from the private key file.

This means that passing --pubkey is typically no longer required,

and makes the key-handling behavior more like OpenSSH.

Upstream-commit: fa7d04fed4d4578fe29bdff0b5465f6e4a7da81a

Signed-off-by: Kamil Dudka <kdudka@redhat.com>

---

 docs/MANUAL | 26 ++++++++++++++-------

 docs/curl.1 |  8 ++++++-

 lib/ssh.c   | 75 +++++++++++++++++++++++++++++++++++++++----------------------

 3 files changed, 73 insertions(+), 36 deletions(-)

diff --git a/docs/MANUAL b/docs/MANUAL

index 4ad2e13..3f8d9b8 100644

--- a/docs/MANUAL

+++ b/docs/MANUAL

@@ -41,12 +41,19 @@ SIMPLE USAGE

   Get a file from an SSH server using SFTP:

-        curl -u username sftp://shell.example.com/etc/issue

+        curl -u username sftp://example.com/etc/issue

-  Get a file from an SSH server using SCP using a private key to authenticate:

+  Get a file from an SSH server using SCP using a private key

+  (not password-protected) to authenticate:

-        curl -u username: --key ~/.ssh/id_dsa --pubkey ~/.ssh/id_dsa.pub \

-            scp://shell.example.com/~/personal.txt

+        curl -u username: --key ~/.ssh/id_rsa \

+             scp://example.com/~/file.txt

+

+  Get a file from an SSH server using SCP using a private key

+  (password-protected) to authenticate:

+

+        curl -u username: --key ~/.ssh/id_rsa --pass private_key_password \

+             scp://example.com/~/file.txt

   Get the main page from an IPv6 web server:

@@ -91,10 +98,13 @@ USING PASSWORDS

  SFTP / SCP

-   This is similar to FTP, but you can specify a private key to use instead of

-   a password. Note that the private key may itself be protected by a password

-   that is unrelated to the login password of the remote system.  If you

-   provide a private key file you must also provide a public key file.

+   This is similar to FTP, but you can use the --key option to specify a

+   private key to use instead of a password. Note that the private key may

+   itself be protected by a password that is unrelated to the login password

+   of the remote system; this password is specified using the --pass option.

+   Typically, curl will automatically extract the public key from the private

+   key file, but in cases where curl does not have the proper library support,

+   a matching public key file must be specified using the --pubkey option.

  HTTP

diff --git a/docs/curl.1 b/docs/curl.1

index 38fa084..d1675a0 100644

--- a/docs/curl.1

+++ b/docs/curl.1

@@ -724,7 +724,8 @@ If this option is used several times, the last one will be used. If

 unspecified, the option defaults to 60 seconds.

 .IP "--key <key>"

 (SSL/SSH) Private key file name. Allows you to provide your private key in this

-separate file.

+separate file. For SSH, if not specified, curl tries the following candidates

+in order: '~/.ssh/id_rsa', '~/.ssh/id_dsa', './id_rsa', './id_dsa'.

 If this option is used several times, the last one will be used.

 .IP "--key-type <type>"

@@ -1124,6 +1125,11 @@ protocol instead of the default HTTP 1.1.

 separate file.

 If this option is used several times, the last one will be used.

+

+(As of 7.39.0, curl attempts to automatically extract the public key from the

+private key file, so passing this option is generally not required. Note that

+this public key extraction requires libcurl to be linked against a copy of

+libssh2 1.2.8 or higher that is itself linked against OpenSSL.)

 .IP "-q"

 If used as the first parameter on the command line, the \fIcurlrc\fP config

 file will not be read and used. See the \fI-K, --config\fP for details on the

diff --git a/lib/ssh.c b/lib/ssh.c

index 43e3342..4ea7d9b 100644

--- a/lib/ssh.c

+++ b/lib/ssh.c

@@ -780,7 +780,7 @@ static CURLcode ssh_statemach_act(struct connectdata *conn, bool *block)

       if((data->set.ssh_auth_types & CURLSSH_AUTH_PUBLICKEY) &&

          (strstr(sshc->authlist, "publickey") != NULL)) {

         char *home = NULL;

-        bool rsa_pub_empty_but_ok = FALSE;

+        bool out_of_memory = FALSE;

         sshc->rsa_pub = sshc->rsa = NULL;

@@ -788,34 +788,55 @@ static CURLcode ssh_statemach_act(struct connectdata *conn, bool *block)

            HOME environment variable etc? */

         home = curl_getenv("HOME");

-        if(data->set.str[STRING_SSH_PUBLIC_KEY] &&

-           !*data->set.str[STRING_SSH_PUBLIC_KEY])

-           rsa_pub_empty_but_ok = true;

-        else if(data->set.str[STRING_SSH_PUBLIC_KEY])

-          sshc->rsa_pub = aprintf("%s", data->set.str[STRING_SSH_PUBLIC_KEY]);

-        else if(home)

-          sshc->rsa_pub = aprintf("%s/.ssh/id_dsa.pub", home);

-        else

-          /* as a final resort, try current dir! */

-          sshc->rsa_pub = strdup("id_dsa.pub");

-

-        if(!rsa_pub_empty_but_ok && (sshc->rsa_pub == NULL)) {

-          Curl_safefree(home);

-          state(conn, SSH_SESSION_FREE);

-          sshc->actualcode = CURLE_OUT_OF_MEMORY;

-          break;

+        if(data->set.str[STRING_SSH_PRIVATE_KEY])

+          sshc->rsa = strdup(data->set.str[STRING_SSH_PRIVATE_KEY]);

+        else {

+          /* If no private key file is specified, try some common paths. */

+          if(home) {

+            /* Try ~/.ssh first. */

+            sshc->rsa = aprintf("%s/.ssh/id_rsa", home);

+            if(!sshc->rsa)

+              out_of_memory = TRUE;

+            else if(access(sshc->rsa, R_OK) != 0) {

+              Curl_safefree(sshc->rsa);

+              sshc->rsa = aprintf("%s/.ssh/id_dsa", home);

+              if(!sshc->rsa)

+                out_of_memory = TRUE;

+              else if(access(sshc->rsa, R_OK) != 0) {

+                Curl_safefree(sshc->rsa);

+              }

+            }

+          }

+          if(!out_of_memory && !sshc->rsa) {

+            /* Nothing found; try the current dir. */

+            sshc->rsa = strdup("id_rsa");

+            if(sshc->rsa && access(sshc->rsa, R_OK) != 0) {

+              Curl_safefree(sshc->rsa);

+              sshc->rsa = strdup("id_dsa");

+              if(sshc->rsa && access(sshc->rsa, R_OK) != 0) {

+                Curl_safefree(sshc->rsa);

+                /* Out of guesses. Set to the empty string to avoid

+                 * surprising info messages. */

+                sshc->rsa = strdup("");

+              }

+            }

+          }

         }

-        if(data->set.str[STRING_SSH_PRIVATE_KEY])

-          sshc->rsa = aprintf("%s", data->set.str[STRING_SSH_PRIVATE_KEY]);

-        else if(home)

-          sshc->rsa = aprintf("%s/.ssh/id_dsa", home);

-        else

-          /* as a final resort, try current dir! */

-          sshc->rsa = strdup("id_dsa");

+        /*

+         * Unless the user explicitly specifies a public key file, let

+         * libssh2 extract the public key from the private key file.

+         * This is done by simply passing sshc->rsa_pub = NULL.

+         */

+        if(data->set.str[STRING_SSH_PUBLIC_KEY]) {

+          sshc->rsa_pub = strdup(data->set.str[STRING_SSH_PUBLIC_KEY]);

+          if(!sshc->rsa_pub)

+            out_of_memory = TRUE;

+        }

-        if(sshc->rsa == NULL) {

+        if(out_of_memory || sshc->rsa == NULL) {

           Curl_safefree(home);

+          Curl_safefree(sshc->rsa);

           Curl_safefree(sshc->rsa_pub);

           state(conn, SSH_SESSION_FREE);

           sshc->actualcode = CURLE_OUT_OF_MEMORY;

@@ -828,8 +849,8 @@ static CURLcode ssh_statemach_act(struct connectdata *conn, bool *block)

         Curl_safefree(home);

-        infof(data, "Using ssh public key file %s\n", sshc->rsa_pub);

-        infof(data, "Using ssh private key file %s\n", sshc->rsa);

+        infof(data, "Using SSH public key file '%s'\n", sshc->rsa_pub);

+        infof(data, "Using SSH private key file '%s'\n", sshc->rsa);

         state(conn, SSH_AUTH_PKEY);

       }

-- 

2.5.2

From 2e18c6a12fc5dbab278670f22e58fcce51d32cac Mon Sep 17 00:00:00 2001

From: Kamil Dudka <kdudka@redhat.com>

Date: Fri, 15 Jan 2016 10:27:33 +0100

Subject: [PATCH 2/2] ssh: make CURLOPT_SSH_PUBLIC_KEYFILE treat "" as NULL

The CURLOPT_SSH_PUBLIC_KEYFILE option has been documented to handle

empty strings specially since curl-7_25_0-31-g05a443a but the behavior

was unintentionally removed in curl-7_38_0-47-gfa7d04f.

This commit restores the original behavior and clarifies it in the

documentation that NULL and "" have both the same meaning when passed

to CURLOPT_SSH_PUBLIC_KEYFILE.

Bug: http://curl.haxx.se/mail/lib-2016-01/0072.html

Upstream-commit: be538e07667e1ba880b7201014be706851428d40

Signed-off-by: Kamil Dudka <kdudka@redhat.com>

---

 docs/libcurl/curl_easy_setopt.3 | 6 +++---

 lib/ssh.c                       | 7 +++++--

 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/docs/libcurl/curl_easy_setopt.3 b/docs/libcurl/curl_easy_setopt.3

index ad739e1..0a9375e 100644

--- a/docs/libcurl/curl_easy_setopt.3

+++ b/docs/libcurl/curl_easy_setopt.3

@@ -2446,9 +2446,9 @@ Pass a char * pointing to a file name for your public key. If not used,

 libcurl defaults to \fB$HOME/.ssh/id_dsa.pub\fP if the HOME environment

 variable is set, and just "id_dsa.pub" in the current directory if HOME is not

 set.  (Added in 7.16.1)

-If an empty string is passed, libcurl will pass no public key to libssh2

-which then tries to compute it from the private key, this is known to work

-when libssh2 1.4.0+ is linked against OpenSSL. (Added in 7.26.0)

+If NULL (or an empty string) is passed, libcurl will pass no public key to

+libssh2, which then tries to compute it from the private key.  This is known

+to work with libssh2 1.4.0+ linked against OpenSSL. (Added in 7.26.0)

 .IP CURLOPT_SSH_PRIVATE_KEYFILE

 Pass a char * pointing to a file name for your private key. If not used,

 libcurl defaults to \fB$HOME/.ssh/id_dsa\fP if the HOME environment variable

diff --git a/lib/ssh.c b/lib/ssh.c

index 4ea7d9b..589d4a3 100644

--- a/lib/ssh.c

+++ b/lib/ssh.c

@@ -828,7 +828,9 @@ static CURLcode ssh_statemach_act(struct connectdata *conn, bool *block)

          * libssh2 extract the public key from the private key file.

          * This is done by simply passing sshc->rsa_pub = NULL.

          */

-        if(data->set.str[STRING_SSH_PUBLIC_KEY]) {

+        if(data->set.str[STRING_SSH_PUBLIC_KEY]

+            /* treat empty string the same way as NULL */

+            && data->set.str[STRING_SSH_PUBLIC_KEY][0]) {

           sshc->rsa_pub = strdup(data->set.str[STRING_SSH_PUBLIC_KEY]);

           if(!sshc->rsa_pub)

             out_of_memory = TRUE;

@@ -849,7 +851,8 @@ static CURLcode ssh_statemach_act(struct connectdata *conn, bool *block)

         Curl_safefree(home);

-        infof(data, "Using SSH public key file '%s'\n", sshc->rsa_pub);

+        if(sshc->rsa_pub)

+          infof(data, "Using SSH public key file '%s'\n", sshc->rsa_pub);

         infof(data, "Using SSH private key file '%s'\n", sshc->rsa);

         state(conn, SSH_AUTH_PKEY);

-- 

2.5.0