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#include "first.h"
#include "base.h"
#include "array.h"
#include "buffer.h"
#include "log.h"
#include "plugin.h"
#include <stdlib.h>
#include <string.h>
typedef struct {
const array *alias;
} plugin_config;
typedef struct {
PLUGIN_DATA;
plugin_config defaults;
plugin_config conf;
} plugin_data;
INIT_FUNC(mod_alias_init) {
return calloc(1, sizeof(plugin_data));
}
static void mod_alias_merge_config_cpv(plugin_config * const pconf, const config_plugin_value_t * const cpv) {
switch (cpv->k_id) { /* index into static config_plugin_keys_t cpk[] */
case 0: /* alias.url */
pconf->alias = cpv->v.a;
break;
default:/* should not happen */
return;
}
}
static void mod_alias_merge_config(plugin_config * const pconf, const config_plugin_value_t *cpv) {
do {
mod_alias_merge_config_cpv(pconf, cpv);
} while ((++cpv)->k_id != -1);
}
static void mod_alias_patch_config(request_st * const r, plugin_data * const p) {
p->conf = p->defaults; /* copy small struct instead of memcpy() */
/*memcpy(&p->conf, &p->defaults, sizeof(plugin_config));*/
for (int i = 1, used = p->nconfig; i < used; ++i) {
if (config_check_cond(r, (uint32_t)p->cvlist[i].k_id))
mod_alias_merge_config(&p->conf, p->cvlist + p->cvlist[i].v.u2[0]);
}
}
static int mod_alias_check_order(server * const srv, const array * const a) {
for (uint32_t j = 0; j < a->used; ++j) {
const buffer * const prefix = &a->data[j]->key;
const size_t plen = buffer_string_length(prefix);
for (uint32_t k = j + 1; k < a->used; ++k) {
const buffer * const key = &a->data[k]->key;
if (buffer_string_length(key) < plen) {
break;
}
if (memcmp(key->ptr, prefix->ptr, plen) != 0) {
break;
}
/* ok, they have same prefix. check position */
const data_unset *dj = a->data[j];
const data_unset *dk = a->data[k];
const data_unset **data = (const data_unset **)a->data;
while (*data != dj && *data != dk) ++data;
if (*data == dj) {
log_error(srv->errh, __FILE__, __LINE__,
"url.alias: `%s' will never match as `%s' matched first",
key->ptr, prefix->ptr);
return 0;
}
}
}
return 1;
}
SETDEFAULTS_FUNC(mod_alias_set_defaults) {
static const config_plugin_keys_t cpk[] = {
{ CONST_STR_LEN("alias.url"),
T_CONFIG_ARRAY_KVSTRING,
T_CONFIG_SCOPE_CONNECTION }
,{ NULL, 0,
T_CONFIG_UNSET,
T_CONFIG_SCOPE_UNSET }
};
plugin_data * const p = p_d;
if (!config_plugin_values_init(srv, p, cpk, "mod_alias"))
return HANDLER_ERROR;
/* process and validate config directives
* (init i to 0 if global context; to 1 to skip empty global context) */
for (int i = !p->cvlist[0].v.u2[1]; i < p->nconfig; ++i) {
const config_plugin_value_t *cpv = p->cvlist + p->cvlist[i].v.u2[0];
for (; -1 != cpv->k_id; ++cpv) {
switch (cpv->k_id) {
case 0: /* alias.url */
if (cpv->v.a->used >= 2 && !mod_alias_check_order(srv,cpv->v.a))
return HANDLER_ERROR;
break;
default:/* should not happen */
break;
}
}
}
/* initialize p->defaults from global config context */
if (p->nconfig > 0 && p->cvlist->v.u2[1]) {
const config_plugin_value_t *cpv = p->cvlist + p->cvlist->v.u2[0];
if (-1 != cpv->k_id)
mod_alias_merge_config(&p->defaults, cpv);
}
return HANDLER_GO_ON;
}
static handler_t
mod_alias_remap (request_st * const r, const array * const aliases)
{
/* do not include trailing slash on basedir */
uint32_t basedir_len = buffer_string_length(&r->physical.basedir);
if ('/' == r->physical.basedir.ptr[basedir_len-1]) --basedir_len;
const uint32_t path_len = buffer_string_length(&r->physical.path);
if (0 == path_len || path_len < basedir_len) return HANDLER_GO_ON;
const uint32_t uri_len = path_len - basedir_len;
const char * const uri_ptr = r->physical.path.ptr + basedir_len;
data_string * const ds = (data_string *)
(!r->conf.force_lowercase_filenames
? array_match_key_prefix_klen(aliases, uri_ptr, uri_len)
: array_match_key_prefix_nc_klen(aliases, uri_ptr, uri_len));
if (NULL == ds) return HANDLER_GO_ON;
/* matched */
const uint32_t alias_len = buffer_string_length(&ds->key);
const uint32_t vlen = buffer_string_length(&ds->value);
/* check for path traversal in url-path following alias if key
* does not end in slash, but replacement value ends in slash */
if (uri_ptr[alias_len] == '.') {
const char *s = uri_ptr + alias_len + 1;
if (*s == '.') ++s;
if (*s == '/' || *s == '\0') {
if (0 != alias_len && ds->key.ptr[alias_len-1] != '/'
&& 0 != vlen && ds->value.ptr[vlen-1] == '/') {
r->http_status = 403;
return HANDLER_FINISHED;
}
}
}
/*(not buffer_append_path_len();
* alias could be prefix instead of complete path segment,
* (though resulting r->physical.basedir would not be a dir))*/
if (vlen != basedir_len + alias_len) {
const uint32_t nlen = vlen + uri_len - alias_len;
if (path_len + buffer_string_space(&r->physical.path) < nlen)
buffer_string_prepare_append(&r->physical.path, nlen - path_len);
memmove(r->physical.path.ptr + vlen,
uri_ptr + alias_len, uri_len - alias_len);
buffer_string_set_length(&r->physical.path, nlen);
}
memcpy(r->physical.path.ptr, ds->value.ptr, vlen);
buffer_copy_string_len(&r->physical.basedir, ds->value.ptr, vlen);
return HANDLER_GO_ON;
}
PHYSICALPATH_FUNC(mod_alias_physical_handler) {
plugin_data * const p = p_d;
mod_alias_patch_config(r, p);
return p->conf.alias ? mod_alias_remap(r, p->conf.alias) : HANDLER_GO_ON;
}
int mod_alias_plugin_init(plugin *p);
int mod_alias_plugin_init(plugin *p) {
p->version = LIGHTTPD_VERSION_ID;
p->name = "alias";
p->init = mod_alias_init;
p->handle_physical= mod_alias_physical_handler;
p->set_defaults = mod_alias_set_defaults;
return 0;
}
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