Merge pull request #2273 from jacquesg/ssh-interactive Add support for SSH keyboard-interactive authentication
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diff --git a/include/git2/transport.h b/include/git2/transport.h
index 1f4d03e..1665f97 100644
--- a/include/git2/transport.h
+++ b/include/git2/transport.h
@@ -41,6 +41,9 @@ typedef enum {
/* git_cred_default */
GIT_CREDTYPE_DEFAULT = (1u << 3),
+
+ /* git_cred_ssh_interactive */
+ GIT_CREDTYPE_SSH_INTERACTIVE = (1u << 4),
} git_credtype_t;
/* The base structure for all credential types */
@@ -60,8 +63,10 @@ typedef struct {
#ifdef GIT_SSH
typedef LIBSSH2_USERAUTH_PUBLICKEY_SIGN_FUNC((*git_cred_sign_callback));
+typedef LIBSSH2_USERAUTH_KBDINT_RESPONSE_FUNC((*git_cred_ssh_interactive_callback));
#else
typedef int (*git_cred_sign_callback)(void *, ...);
+typedef int (*git_cred_ssh_interactive_callback)(void *, ...);
#endif
/**
@@ -76,6 +81,16 @@ typedef struct git_cred_ssh_key {
} git_cred_ssh_key;
/**
+ * Keyboard-interactive based ssh authentication
+ */
+typedef struct git_cred_ssh_interactive {
+ git_cred parent;
+ char *username;
+ git_cred_ssh_interactive_callback prompt_callback;
+ void *payload;
+} git_cred_ssh_interactive;
+
+/**
* A key with a custom signature function
*/
typedef struct git_cred_ssh_custom {
@@ -83,8 +98,8 @@ typedef struct git_cred_ssh_custom {
char *username;
char *publickey;
size_t publickey_len;
- void *sign_callback;
- void *sign_data;
+ git_cred_sign_callback sign_callback;
+ void *payload;
} git_cred_ssh_custom;
/** A key for NTLM/Kerberos "default" credentials */
@@ -131,6 +146,21 @@ GIT_EXTERN(int) git_cred_ssh_key_new(
const char *passphrase);
/**
+ * Create a new ssh keyboard-interactive based credential object.
+ * The supplied credential parameter will be internally duplicated.
+ *
+ * @param username Username to use to authenticate.
+ * @param prompt_callback The callback method used for prompts.
+ * @param payload Additional data to pass to the callback.
+ * @return 0 for success or an error code for failure.
+ */
+GIT_EXTERN(int) git_cred_ssh_interactive_new(
+ git_cred **out,
+ const char *username,
+ git_cred_ssh_interactive_callback prompt_callback,
+ void *payload);
+
+/**
* Create a new ssh key credential object used for querying an ssh-agent.
* The supplied credential parameter will be internally duplicated.
*
@@ -156,8 +186,8 @@ GIT_EXTERN(int) git_cred_ssh_key_from_agent(
* @param username username to use to authenticate
* @param publickey The bytes of the public key.
* @param publickey_len The length of the public key in bytes.
- * @param sign_fn The callback method to sign the data during the challenge.
- * @param sign_data The data to pass to the sign function.
+ * @param sign_callback The callback method to sign the data during the challenge.
+ * @param payload Additional data to pass to the callback.
* @return 0 for success or an error code for failure
*/
GIT_EXTERN(int) git_cred_ssh_custom_new(
@@ -165,8 +195,8 @@ GIT_EXTERN(int) git_cred_ssh_custom_new(
const char *username,
const char *publickey,
size_t publickey_len,
- git_cred_sign_callback sign_fn,
- void *sign_data);
+ git_cred_sign_callback sign_callback,
+ void *payload);
/**
* Create a "default" credential usable for Negotiate mechanisms like NTLM
diff --git a/src/transports/cred.c b/src/transports/cred.c
index 460ed04..913ec36 100644
--- a/src/transports/cred.c
+++ b/src/transports/cred.c
@@ -30,7 +30,6 @@ static void plaintext_free(struct git_cred *cred)
git__free(c->password);
}
- git__memzero(c, sizeof(*c));
git__free(c);
}
@@ -73,8 +72,13 @@ static void ssh_key_free(struct git_cred *cred)
(git_cred_ssh_key *)cred;
git__free(c->username);
- git__free(c->publickey);
- git__free(c->privatekey);
+
+ if (c->privatekey) {
+ /* Zero the memory which previously held the private key */
+ size_t key_len = strlen(c->privatekey);
+ git__memzero(c->privatekey, key_len);
+ git__free(c->privatekey);
+ }
if (c->passphrase) {
/* Zero the memory which previously held the passphrase */
@@ -83,7 +87,22 @@ static void ssh_key_free(struct git_cred *cred)
git__free(c->passphrase);
}
- git__memzero(c, sizeof(*c));
+ if (c->publickey) {
+ /* Zero the memory which previously held the public key */
+ size_t key_len = strlen(c->publickey);
+ git__memzero(c->publickey, key_len);
+ git__free(c->publickey);
+ }
+
+ git__free(c);
+}
+
+static void ssh_interactive_free(struct git_cred *cred)
+{
+ git_cred_ssh_interactive *c = (git_cred_ssh_interactive *)cred;
+
+ git__free(c->username);
+
git__free(c);
}
@@ -92,9 +111,14 @@ static void ssh_custom_free(struct git_cred *cred)
git_cred_ssh_custom *c = (git_cred_ssh_custom *)cred;
git__free(c->username);
- git__free(c->publickey);
- git__memzero(c, sizeof(*c));
+ if (c->publickey) {
+ /* Zero the memory which previously held the publickey */
+ size_t key_len = strlen(c->publickey);
+ git__memzero(c->publickey, key_len);
+ git__free(c->publickey);
+ }
+
git__free(c);
}
@@ -142,6 +166,32 @@ int git_cred_ssh_key_new(
return 0;
}
+int git_cred_ssh_interactive_new(
+ git_cred **out,
+ const char *username,
+ git_cred_ssh_interactive_callback prompt_callback,
+ void *payload)
+{
+ git_cred_ssh_interactive *c;
+
+ assert(out && username && prompt_callback);
+
+ c = git__calloc(1, sizeof(git_cred_ssh_interactive));
+ GITERR_CHECK_ALLOC(c);
+
+ c->parent.credtype = GIT_CREDTYPE_SSH_INTERACTIVE;
+ c->parent.free = ssh_interactive_free;
+
+ c->username = git__strdup(username);
+ GITERR_CHECK_ALLOC(c->username);
+
+ c->prompt_callback = prompt_callback;
+ c->payload = payload;
+
+ *out = &c->parent;
+ return 0;
+}
+
int git_cred_ssh_key_from_agent(git_cred **cred, const char *username) {
git_cred_ssh_key *c;
@@ -168,7 +218,7 @@ int git_cred_ssh_custom_new(
const char *publickey,
size_t publickey_len,
git_cred_sign_callback sign_callback,
- void *sign_data)
+ void *payload)
{
git_cred_ssh_custom *c;
@@ -192,7 +242,7 @@ int git_cred_ssh_custom_new(
c->publickey_len = publickey_len;
c->sign_callback = sign_callback;
- c->sign_data = sign_data;
+ c->payload = payload;
*cred = &c->parent;
return 0;
diff --git a/src/transports/ssh.c b/src/transports/ssh.c
index 879af90..dea9902 100644
--- a/src/transports/ssh.c
+++ b/src/transports/ssh.c
@@ -310,7 +310,28 @@ static int _git_ssh_authenticate_session(
rc = libssh2_userauth_publickey(
session, c->username, (const unsigned char *)c->publickey,
- c->publickey_len, c->sign_callback, &c->sign_data);
+ c->publickey_len, c->sign_callback, &c->payload);
+ break;
+ }
+ case GIT_CREDTYPE_SSH_INTERACTIVE: {
+ void **abstract = libssh2_session_abstract(session);
+ git_cred_ssh_interactive *c = (git_cred_ssh_interactive *)cred;
+
+ /* ideally, we should be able to set this by calling
+ * libssh2_session_init_ex() instead of libssh2_session_init().
+ * libssh2's API is inconsistent here i.e. libssh2_userauth_publickey()
+ * allows you to pass the `abstract` as part of the call, whereas
+ * libssh2_userauth_keyboard_interactive() does not!
+ *
+ * The only way to set the `abstract` pointer is by calling
+ * libssh2_session_abstract(), which will replace the existing
+ * pointer as is done below. This is safe for now (at time of writing),
+ * but may not be valid in future.
+ */
+ *abstract = c->payload;
+
+ rc = libssh2_userauth_keyboard_interactive(
+ session, c->username, c->prompt_callback);
break;
}
default:
@@ -397,6 +418,7 @@ static int _git_ssh_setup_conn(
&t->cred, t->owner->url, user,
GIT_CREDTYPE_USERPASS_PLAINTEXT |
GIT_CREDTYPE_SSH_KEY |
+ GIT_CREDTYPE_SSH_INTERACTIVE |
GIT_CREDTYPE_SSH_CUSTOM,
t->owner->cred_acquire_payload) < 0)
goto on_error;