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fix: memory leaks in gssapi.c

Browse Source 
fix: implement gssapi logging according to docs

fix: remove redundant setting of session->gssapi to NULL

feat: add gssapi struct and functions to header file

refactor: initialize gssapi context once

fix: remove redundant ssh_gssapi_free

Signed-off-by: Gauravsingh Sisodia <xaerru@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Sahana Prasad <sahana@redhat.com>
This commit is contained in:
Gauravsingh Sisodia
2024-05-14 10:37:48 +00:00
committed by Sahana Prasad
parent 74d42ca38b
commit 965a94b515
6 changed files with 116 additions and 113 deletions
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33
include/libssh/gssapi.h
View File

@ -22,7 +22,9 @@
#define GSSAPI_H_
#include "config.h"
#ifdef WITH_GSSAPI
#include "session.h"
#include <gssapi/gssapi.h>
/* all OID begin with the tag identifier + length */
#define SSH_OID_TAG 06
@ -33,6 +35,32 @@ typedef struct ssh_gssapi_struct *ssh_gssapi;
extern "C" {
#endif
/** current state of an GSSAPI authentication */
enum ssh_gssapi_state_e {
SSH_GSSAPI_STATE_NONE, /* no status */
SSH_GSSAPI_STATE_RCV_TOKEN, /* Expecting a token */
SSH_GSSAPI_STATE_RCV_MIC, /* Expecting a MIC */
};
struct ssh_gssapi_struct{
enum ssh_gssapi_state_e state; /* current state */
struct gss_OID_desc_struct mech; /* mechanism being elected for auth */
gss_cred_id_t server_creds; /* credentials of server */
gss_cred_id_t client_creds; /* creds delegated by the client */
gss_ctx_id_t ctx; /* the authentication context */
gss_name_t client_name; /* Identity of the client */
char *user; /* username of client */
char *canonic_user; /* canonic form of the client's username */
char *service; /* name of the service */
struct {
gss_name_t server_name; /* identity of server */
OM_uint32 flags; /* flags used for init context */
gss_OID oid; /* mech being used for authentication */
gss_cred_id_t creds; /* creds used to initialize context */
gss_cred_id_t client_deleg_creds; /* delegated creds (const, not freeable) */
} client;
};
#ifdef WITH_SERVER
int ssh_gssapi_handle_userauth(ssh_session session, const char *user, uint32_t n_oid, ssh_string *oids);
SSH_PACKET_CALLBACK(ssh_packet_userauth_gssapi_token_server);
@ -44,10 +72,15 @@ SSH_PACKET_CALLBACK(ssh_packet_userauth_gssapi_token_client);
SSH_PACKET_CALLBACK(ssh_packet_userauth_gssapi_response);
int ssh_gssapi_init(ssh_session session);
void ssh_gssapi_log_error(int verb, const char *msg_a, int maj_stat, int min_stat);
int ssh_gssapi_auth_mic(ssh_session session);
void ssh_gssapi_free(ssh_session session);
char *ssh_gssapi_name_to_char(gss_name_t name);
#ifdef __cplusplus
}
#endif
#endif /* WITH_GSSAPI */
#endif /* GSSAPI_H */

179
src/gssapi.c
View File

@ -38,37 +38,11 @@
#include <libssh/string.h>
#include <libssh/server.h>
/** current state of an GSSAPI authentication */
enum ssh_gssapi_state_e {
SSH_GSSAPI_STATE_NONE, /* no status */
SSH_GSSAPI_STATE_RCV_TOKEN, /* Expecting a token */
SSH_GSSAPI_STATE_RCV_MIC, /* Expecting a MIC */
};
struct ssh_gssapi_struct{
enum ssh_gssapi_state_e state; /* current state */
struct gss_OID_desc_struct mech; /* mechanism being elected for auth */
gss_cred_id_t server_creds; /* credentials of server */
gss_cred_id_t client_creds; /* creds delegated by the client */
gss_ctx_id_t ctx; /* the authentication context */
gss_name_t client_name; /* Identity of the client */
char *user; /* username of client */
char *canonic_user; /* canonic form of the client's username */
char *service; /* name of the service */
struct {
gss_name_t server_name; /* identity of server */
OM_uint32 flags; /* flags used for init context */
gss_OID oid; /* mech being used for authentication */
gss_cred_id_t creds; /* creds used to initialize context */
gss_cred_id_t client_deleg_creds; /* delegated creds (const, not freeable) */
} client;
};
/** @internal
* @initializes a gssapi context for authentication
*/
static int ssh_gssapi_init(ssh_session session)
int
ssh_gssapi_init(ssh_session session)
{
if (session->gssapi != NULL)
return SSH_OK;
@ -84,21 +58,60 @@ static int ssh_gssapi_init(ssh_session session)
return SSH_OK;
}
void
ssh_gssapi_log_error(int verb, const char *msg_a, int maj_stat, int min_stat)
{
gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
OM_uint32 dummy_min;
OM_uint32 message_context = 0;
do {
gss_display_status(&dummy_min,
maj_stat,
GSS_C_GSS_CODE,
GSS_C_NO_OID,
&message_context,
&msg);
SSH_LOG(verb, "GSSAPI(%s): %s", msg_a, (const char *)msg.value);
gss_release_buffer(&dummy_min, &msg);
} while (message_context != 0);
do {
gss_display_status(&dummy_min,
min_stat,
GSS_C_MECH_CODE,
GSS_C_NO_OID,
&message_context,
&msg);
SSH_LOG(verb, "GSSAPI(%s): %s", msg_a, (const char *)msg.value);
gss_release_buffer(&dummy_min, &msg);
} while (message_context != 0);
}
/** @internal
* @frees a gssapi context
*/
static void ssh_gssapi_free(ssh_session session)
void
ssh_gssapi_free(ssh_session session)
{
OM_uint32 min;
if (session->gssapi == NULL)
return;
SAFE_FREE(session->gssapi->user);
SAFE_FREE(session->gssapi->mech.elements);
gss_release_name(&min, &session->gssapi->client.server_name);
gss_release_cred(&min,&session->gssapi->server_creds);
if (session->gssapi->client.creds !=
session->gssapi->client.client_deleg_creds) {
gss_release_cred(&min, &session->gssapi->client.creds);
}
gss_release_oid(&min, &session->gssapi->client.oid);
gss_delete_sec_context(&min, &session->gssapi->ctx, GSS_C_NO_BUFFER);
SAFE_FREE(session->gssapi->mech.elements);
SAFE_FREE(session->gssapi->canonic_user);
SAFE_FREE(session->gssapi);
}
@ -132,55 +145,6 @@ static int ssh_gssapi_send_response(ssh_session session, ssh_string oid)
#endif /* WITH_SERVER */
static void ssh_gssapi_log_error(int verb,
const char *msg,
int maj_stat,
int min_stat)
{
gss_buffer_desc msg_maj = {
.length = 0,
};
gss_buffer_desc msg_min = {
.length = 0,
};
OM_uint32 dummy_maj, dummy_min;
OM_uint32 message_context = 0;
dummy_maj = gss_display_status(&dummy_min,
maj_stat,
GSS_C_GSS_CODE,
GSS_C_NO_OID,
&message_context,
&msg_maj);
if (dummy_maj != 0) {
goto out;
}
dummy_maj = gss_display_status(&dummy_min,
min_stat,
GSS_C_MECH_CODE,
GSS_C_NO_OID,
&message_context,
&msg_min);
if (dummy_maj != 0) {
goto out;
}
SSH_LOG(verb,
"GSSAPI(%s): %s - %s",
msg,
(const char *)msg_maj.value,
(const char *)msg_min.value);
out:
if (msg_maj.value) {
gss_release_buffer(&dummy_min, &msg_maj);
}
if (msg_min.value) {
gss_release_buffer(&dummy_min, &msg_min);
}
}
#ifdef WITH_SERVER
/** @internal
@ -204,16 +168,27 @@ ssh_gssapi_handle_userauth(ssh_session session, const char *user,
struct gss_OID_desc_struct oid;
int rc;
if (ssh_callbacks_exists(session->server_callbacks, gssapi_select_oid_function)){
ssh_string oid_s = session->server_callbacks->gssapi_select_oid_function(session,
user, n_oid, oids,
/* Destroy earlier GSSAPI context if any */
ssh_gssapi_free(session);
rc = ssh_gssapi_init(session);
if (rc == SSH_ERROR)
return rc;
/* Callback should select oid and acquire credential */
if (ssh_callbacks_exists(session->server_callbacks,
gssapi_select_oid_function)) {
ssh_string oid_s = NULL;
session->gssapi->state = SSH_GSSAPI_STATE_RCV_TOKEN;
SAFE_FREE(session->gssapi->user);
session->gssapi->user = strdup(user);
oid_s = session->server_callbacks->gssapi_select_oid_function(
session,
user,
n_oid,
oids,
session->server_callbacks->userdata);
if (oid_s != NULL) {
if (ssh_gssapi_init(session) == SSH_ERROR)
return SSH_ERROR;
session->gssapi->state = SSH_GSSAPI_STATE_RCV_TOKEN;
rc = ssh_gssapi_send_response(session, oid_s);
SSH_STRING_FREE(oid_s);
return rc;
} else {
return ssh_auth_reply_default(session, 0);
@ -264,11 +239,6 @@ ssh_gssapi_handle_userauth(ssh_session session, const char *user,
gss_release_oid_set(&min_stat, &both_supported);
return SSH_OK;
}
/* from now we have room for context */
if (ssh_gssapi_init(session) == SSH_ERROR) {
gss_release_oid_set(&min_stat, &both_supported);
return SSH_ERROR;
}
name_buf.value = service_name;
name_buf.length = strlen(name_buf.value) + 1;
@ -337,7 +307,8 @@ ssh_gssapi_handle_userauth(ssh_session session, const char *user,
return ssh_gssapi_send_response(session, oids[i]);
}
static char *ssh_gssapi_name_to_char(gss_name_t name)
char *
ssh_gssapi_name_to_char(gss_name_t name)
{
gss_buffer_desc buffer;
OM_uint32 maj_stat, min_stat;
@ -390,8 +361,6 @@ SSH_PACKET_CALLBACK(ssh_packet_userauth_gssapi_token_server){
token, &out_token, session->server_callbacks->userdata);
if (rc == SSH_ERROR){
ssh_auth_reply_default(session, 0);
ssh_gssapi_free(session);
session->gssapi=NULL;
return SSH_PACKET_USED;
}
if (ssh_string_len(out_token) != 0){
@ -405,9 +374,8 @@ SSH_PACKET_CALLBACK(ssh_packet_userauth_gssapi_token_server){
}
ssh_packet_send(session);
SSH_STRING_FREE(out_token);
} else {
session->gssapi->state = SSH_GSSAPI_STATE_RCV_MIC;
}
session->gssapi->state = SSH_GSSAPI_STATE_RCV_MIC;
return SSH_PACKET_USED;
}
hexa = ssh_get_hexa(ssh_string_data(token),ssh_string_len(token));
@ -435,8 +403,6 @@ SSH_PACKET_CALLBACK(ssh_packet_userauth_gssapi_token_server){
min_stat);
gss_release_buffer(&min_stat, &output_token);
ssh_auth_reply_default(session,0);
ssh_gssapi_free(session);
session->gssapi=NULL;
return SSH_PACKET_USED;
}
@ -452,14 +418,13 @@ SSH_PACKET_CALLBACK(ssh_packet_userauth_gssapi_token_server){
if (rc != SSH_OK) {
ssh_set_error_oom(session);
ssh_auth_reply_default(session, 0);
ssh_gssapi_free(session);
session->gssapi = NULL;
return SSH_PACKET_USED;
}
ssh_packet_send(session);
}
gss_release_buffer(&min_stat, &output_token);
gss_release_name(&min_stat, &client_name);
if(maj_stat == GSS_S_COMPLETE){
session->gssapi->state = SSH_GSSAPI_STATE_RCV_MIC;
@ -578,7 +543,6 @@ error:
ssh_auth_reply_default(session,0);
end:
ssh_gssapi_free(session);
if (mic_buffer != NULL) {
SSH_BUFFER_FREE(mic_buffer);
}
@ -691,6 +655,10 @@ static int ssh_gssapi_match(ssh_session session, gss_OID_set *valid_oids)
&session->gssapi->client.creds,
&actual_mechs, NULL);
if (GSS_ERROR(maj_stat)) {
ssh_gssapi_log_error(SSH_LOG_DEBUG,
"acquiring credential",
maj_stat,
min_stat);
ret = SSH_ERROR;
goto end;
}
@ -751,6 +719,8 @@ int ssh_gssapi_auth_mic(ssh_session session)
gss_buffer_desc hostname;
const char *gss_host = session->opts.host;
/* Destroy earlier GSSAPI context if any */
ssh_gssapi_free(session);
rc = ssh_gssapi_init(session);
if (rc == SSH_ERROR) {
return SSH_AUTH_ERROR;
@ -935,8 +905,6 @@ SSH_PACKET_CALLBACK(ssh_packet_userauth_gssapi_response){
error:
session->auth.state = SSH_AUTH_STATE_ERROR;
ssh_gssapi_free(session);
session->gssapi = NULL;
return SSH_PACKET_USED;
}
@ -1060,14 +1028,9 @@ SSH_PACKET_CALLBACK(ssh_packet_userauth_gssapi_token_client){
session->auth.state = SSH_AUTH_STATE_GSSAPI_MIC_SENT;
}
ssh_gssapi_free(session);
session->gssapi = NULL;
return SSH_PACKET_USED;
error:
session->auth.state = SSH_AUTH_STATE_ERROR;
ssh_gssapi_free(session);
session->gssapi = NULL;
return SSH_PACKET_USED;
}

5
src/session.c
View File

@ -39,6 +39,7 @@
#include "libssh/buffer.h"
#include "libssh/poll.h"
#include "libssh/pki.h"
#include "libssh/gssapi.h"
#define FIRST_CHANNEL 42 // why not ? it helps to find bugs.
@ -287,6 +288,10 @@ void ssh_free(ssh_session session)
ssh_list_free(session->packet_callbacks);
}
#ifdef WITH_GSSAPI
ssh_gssapi_free(session);
#endif
/* options */
if (session->opts.identity) {
char *id;

2
tests/server/test_server/default_cb.c
View File

@ -923,7 +923,7 @@ void default_handle_session_cb(ssh_event event,
if (ssh_event_dopoll(event, 100) == SSH_ERROR) {
fprintf(stderr, "do_poll error: %s\n", ssh_get_error(session));
return;
goto end;
}
n++;
}

2
tests/server/test_server/test_server.c
View File

@ -56,6 +56,8 @@ void free_server_state(struct server_state_st *state)
SAFE_FREE(state->expected_password);
SAFE_FREE(state->config_file);
SAFE_FREE(state->log_file);
SAFE_FREE(state->server_cb);
SAFE_FREE(state->channel_cb);
}
/* SIGCHLD handler for cleaning up dead children. */