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Bug #2216 ยป mod_userdir.c

DanielRichman, 2010-05-31 20:56

 
#include "base.h"
#include "log.h"
#include "buffer.h"

#include "response.h"

#include "plugin.h"

#include <sys/types.h>

#include <stdlib.h>
#include <string.h>

#ifdef HAVE_PWD_H
# include <pwd.h>
#endif

/* plugin config for all request/connections */
typedef struct {
array *exclude_user;
array *include_user;
buffer *path;
buffer *basepath;
unsigned short letterhomes;
} plugin_config;

typedef struct {
PLUGIN_DATA;

buffer *username;
buffer *temp_path;

plugin_config **config_storage;

plugin_config conf;
} plugin_data;

/* init the plugin data */
INIT_FUNC(mod_userdir_init) {
plugin_data *p;

p = calloc(1, sizeof(*p));

p->username = buffer_init();
p->temp_path = buffer_init();

return p;
}

/* detroy the plugin data */
FREE_FUNC(mod_userdir_free) {
plugin_data *p = p_d;

if (!p) return HANDLER_GO_ON;

if (p->config_storage) {
size_t i;

for (i = 0; i < srv->config_context->used; i++) {
plugin_config *s = p->config_storage[i];

array_free(s->include_user);
array_free(s->exclude_user);
buffer_free(s->path);
buffer_free(s->basepath);

free(s);
}
free(p->config_storage);
}

buffer_free(p->username);
buffer_free(p->temp_path);

free(p);

return HANDLER_GO_ON;
}

/* handle plugin config and check values */

SETDEFAULTS_FUNC(mod_userdir_set_defaults) {
plugin_data *p = p_d;
size_t i;

config_values_t cv[] = {
{ "userdir.path", NULL, T_CONFIG_STRING, T_CONFIG_SCOPE_CONNECTION }, /* 0 */
{ "userdir.exclude-user", NULL, T_CONFIG_ARRAY, T_CONFIG_SCOPE_CONNECTION }, /* 1 */
{ "userdir.include-user", NULL, T_CONFIG_ARRAY, T_CONFIG_SCOPE_CONNECTION }, /* 2 */
{ "userdir.basepath", NULL, T_CONFIG_STRING, T_CONFIG_SCOPE_CONNECTION }, /* 3 */
{ "userdir.letterhomes", NULL, T_CONFIG_BOOLEAN,T_CONFIG_SCOPE_CONNECTION }, /* 4 */
{ NULL, NULL, T_CONFIG_UNSET, T_CONFIG_SCOPE_UNSET }
};

if (!p) return HANDLER_ERROR;

p->config_storage = calloc(1, srv->config_context->used * sizeof(specific_config *));

for (i = 0; i < srv->config_context->used; i++) {
plugin_config *s;

s = calloc(1, sizeof(plugin_config));
s->exclude_user = array_init();
s->include_user = array_init();
s->path = buffer_init();
s->basepath = buffer_init();
s->letterhomes = 0;

cv[0].destination = s->path;
cv[1].destination = s->exclude_user;
cv[2].destination = s->include_user;
cv[3].destination = s->basepath;
cv[4].destination = &(s->letterhomes);

p->config_storage[i] = s;

if (0 != config_insert_values_global(srv, ((data_config *)srv->config_context->data[i])->value, cv)) {
return HANDLER_ERROR;
}
}

return HANDLER_GO_ON;
}

#define PATCH(x) \
p->conf.x = s->x;
static int mod_userdir_patch_connection(server *srv, connection *con, plugin_data *p) {
size_t i, j;
plugin_config *s = p->config_storage[0];

PATCH(path);
PATCH(exclude_user);
PATCH(include_user);
PATCH(basepath);
PATCH(letterhomes);

/* skip the first, the global context */
for (i = 1; i < srv->config_context->used; i++) {
data_config *dc = (data_config *)srv->config_context->data[i];
s = p->config_storage[i];

/* condition didn't match */
if (!config_check_cond(srv, con, dc)) continue;

/* merge config */
for (j = 0; j < dc->value->used; j++) {
data_unset *du = dc->value->data[j];

if (buffer_is_equal_string(du->key, CONST_STR_LEN("userdir.path"))) {
PATCH(path);
} else if (buffer_is_equal_string(du->key, CONST_STR_LEN("userdir.exclude-user"))) {
PATCH(exclude_user);
} else if (buffer_is_equal_string(du->key, CONST_STR_LEN("userdir.include-user"))) {
PATCH(include_user);
} else if (buffer_is_equal_string(du->key, CONST_STR_LEN("userdir.basepath"))) {
PATCH(basepath);
} else if (buffer_is_equal_string(du->key, CONST_STR_LEN("userdir.letterhomes"))) {
PATCH(letterhomes);
}
}
}

return 0;
}
#undef PATCH

URIHANDLER_FUNC(mod_userdir_docroot_handler) {
plugin_data *p = p_d;
int uri_len;
size_t k;
char *rel_url;
#ifdef HAVE_PWD_H
struct passwd *pwd = NULL;
#endif

if (con->uri.path->used == 0) return HANDLER_GO_ON;

mod_userdir_patch_connection(srv, con, p);

/* enforce the userdir.path to be set in the config, ugly fix for #1587;
* should be replaced with a clean .enabled option in 1.5
*/
if (p->conf.path->used == 0) return HANDLER_GO_ON;

uri_len = con->uri.path->used - 1;

/* /~user/foo.html -> /home/user/public_html/foo.html */

if (con->uri.path->ptr[0] != '/' ||
con->uri.path->ptr[1] != '~') return HANDLER_GO_ON;

if (NULL == (rel_url = strchr(con->uri.path->ptr + 2, '/'))) {
/* / is missing -> redirect to .../ as we are a user - DIRECTORY ! :) */
http_response_redirect_to_directory(srv, con);

return HANDLER_FINISHED;
}

/* /~/ is a empty username, catch it directly */
if (0 == rel_url - (con->uri.path->ptr + 2)) {
return HANDLER_GO_ON;
}

buffer_copy_string_len(p->username, con->uri.path->ptr + 2, rel_url - (con->uri.path->ptr + 2));

if (buffer_is_empty(p->conf.basepath)
#ifdef HAVE_PWD_H
&& NULL == (pwd = getpwnam(p->username->ptr))
#endif
) {
/* user not found */
return HANDLER_GO_ON;
}


for (k = 0; k < p->conf.exclude_user->used; k++) {
data_string *ds = (data_string *)p->conf.exclude_user->data[k];

if (buffer_is_equal(ds->value, p->username)) {
/* user in exclude list */
return HANDLER_GO_ON;
}
}

if (p->conf.include_user->used) {
int found_user = 0;
for (k = 0; k < p->conf.include_user->used; k++) {
data_string *ds = (data_string *)p->conf.include_user->data[k];

if (buffer_is_equal(ds->value, p->username)) {
/* user in include list */
found_user = 1;
break;
}
}

if (!found_user) return HANDLER_GO_ON;
}

/* we build the physical path */

if (buffer_is_empty(p->conf.basepath)) {
#ifdef HAVE_PWD_H
buffer_copy_string(p->temp_path, pwd->pw_dir);
#endif
} else {
char *cp;
/* check if the username is valid
* a request for /~../ should lead to a directory traversal
* limiting to [-_a-z0-9.] should fix it */

for (cp = p->username->ptr; *cp; cp++) {
char c = *cp;

if (!(c == '-' ||
c == '_' ||
c == '.' ||
(c >= 'a' && c <= 'z') ||
(c >= 'A' && c <= 'Z') ||
(c >= '0' && c <= '9'))) {

return HANDLER_GO_ON;
}
}
if (con->conf.force_lowercase_filenames) {
buffer_to_lower(p->username);
}

buffer_copy_string_buffer(p->temp_path, p->conf.basepath);
BUFFER_APPEND_SLASH(p->temp_path);
if (p->conf.letterhomes) {
buffer_append_string_len(p->temp_path, p->username->ptr, 1);
BUFFER_APPEND_SLASH(p->temp_path);
}
buffer_append_string_buffer(p->temp_path, p->username);
}
BUFFER_APPEND_SLASH(p->temp_path);
buffer_append_string_buffer(p->temp_path, p->conf.path);

if (buffer_is_empty(p->conf.basepath)) {
struct stat st;
int ret;

ret = stat(p->temp_path->ptr, &st);
if (ret < 0 || S_ISDIR(st.st_mode) != 1) {
return HANDLER_GO_ON;
}
}

/* the physical rel_path is basically the same as uri.path;
* but it is converted to lowercase in case of force_lowercase_filenames and some special handling
* for trailing '.', ' ' and '/' on windows
* we assume that no docroot/physical handler changed this
* (docroot should only set the docroot/server name, phyiscal should only change the phyiscal.path;
* the exception mod_secure_download doesn't work with userdir anyway)
*/
BUFFER_APPEND_SLASH(p->temp_path);
/* if no second '/' is found, we assume that it was stripped from the uri.path for the special handling
* on windows.
* we do not care about the trailing slash here on windows, as we already ensured it is a directory
*
* TODO: what to do with trailing dots in usernames on windows? they may result in the same directory
* as a username without them.
*/
buffer_copy_string_buffer(con->physical.doc_root, p->temp_path);
if (NULL != (rel_url = strchr(con->physical.rel_path->ptr + 2, '/'))) {
buffer_append_string(p->temp_path, rel_url + 1); /* skip the / */
}
buffer_copy_string_buffer(con->physical.path, p->temp_path);

buffer_reset(p->temp_path);

return HANDLER_GO_ON;
}

/* this function is called at dlopen() time and inits the callbacks */

int mod_userdir_plugin_init(plugin *p);
int mod_userdir_plugin_init(plugin *p) {
p->version = LIGHTTPD_VERSION_ID;
p->name = buffer_init_string("userdir");

p->init = mod_userdir_init;
p->handle_physical = mod_userdir_docroot_handler;
p->set_defaults = mod_userdir_set_defaults;
p->cleanup = mod_userdir_free;

p->data = NULL;

return 0;
}
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