Implements the $arg_encode_<name> variables for get url encode value of <name> argument from request

Kirill_ASKorinskiy · March 25, 2009, 6:27pm

Raw value of arguments from request string can help for XSS.

src/http/ngx_http_variables.c | 54
+++++++++++++++++++++++++++++++++++++++++
1 files changed, 54 insertions(+), 0 deletions(-)

diff --git a/src/http/ngx_http_variables.c
b/src/http/ngx_http_variables.c
index
22f213cf6157ab5b99e481835acf9a394ef21919…d5a7923343797c268cd70cdd2e87a70887a41419
100644
— a/src/http/ngx_http_variables.c
+++ b/src/http/ngx_http_variables.c
@@ -31,6 +31,8 @@ static ngx_int_t
ngx_http_variable_cookie(ngx_http_request_t *r,
static ngx_int_t ngx_http_variable_ssi(ngx_http_request_t *r,
ngx_http_variable_value_t *v, uintptr_t data);
#endif
+static ngx_int_t ngx_http_variable_encode_argument(ngx_http_request_t
*r,

ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_argument(ngx_http_request_t *r,
ngx_http_variable_value_t *v, uintptr_t data);

@@ -530,6 +532,15 @@ ngx_http_get_variable(ngx_http_request_t *r,
ngx_str_t *name, ngx_uint_t key,
}
#endif

if (ngx_strncmp(name->data, “arg_encode_”, 11) == 0) {

   if (ngx_http_variable_encode_argument(r, vv, (uintptr_t) name)

== NGX_OK) {

```
       return vv;
```
```
   }
```
```
   return NULL;
```
}

if (ngx_strncmp(name->data, “arg_”, 4) == 0) {

   if (ngx_http_variable_argument(r, vv, (uintptr_t) name) ==

NGX_OK) {
@@ -831,6 +842,42 @@ ngx_http_variable_ssi(ngx_http_request_t *r,
ngx_http_variable_value_t *v,

static ngx_int_t
+ngx_http_variable_encode_argument(ngx_http_request_t *r,
ngx_http_variable_value_t *v,

uintptr_t data)
+{
ngx_str_t *name = (ngx_str_t *) data;
u_char *arg;
size_t len;
ngx_str_t value;
len = name->len - (sizeof(“arg_encode_”) - 1);
arg = name->data + sizeof(“arg_encode_”) - 1;
if (ngx_http_arg(r, arg, len, &value) != NGX_OK) {
```
   v->not_found = 1;
```
```
   return NGX_OK;
```
}
v->len = value.len +
2 * ngx_escape_uri(NULL, value.data, value.len, NGX_ESCAPE_ARGS);
v->data = ngx_palloc(r->pool, v->len);
if (v->data == NULL) {
```
   v->not_found = 1;
```
```
   return NGX_OK;
```
}
(void) ngx_escape_uri(v->data, value.data, value.len,
NGX_ESCAPE_ARGS);
v->valid = 1;
v->no_cacheable = 0;
v->not_found = 0;
return NGX_OK;
+}

+static ngx_int_t
ngx_http_variable_argument(ngx_http_request_t *r,
ngx_http_variable_value_t *v,
uintptr_t data)
{
@@ -1789,6 +1836,13 @@ ngx_http_variables_init_vars(ngx_conf_t *cf)
}
#endif

   if (ngx_strncmp(v[i].name.data, "arg_encode_", 11) == 0) {

       v[i].get_handler = ngx_http_variable_encode_argument;

       v[i].data = (uintptr_t) &v[i].name;

```
       continue;
```
```
   }
```

   if (ngx_strncmp(v[i].name.data, "arg_", 4) == 0) {
       v[i].get_handler = ngx_http_variable_argument;
       v[i].data = (uintptr_t) &v[i].name;

Kirill_ASKorinskiy · March 25, 2009, 6:30pm

On Wed, Mar 25, 2009 at 08:15:33PM +0300, Kirill A. Korinskiy wrote:

Raw value of arguments from request string can help for XSS.

Probably, $encoded_arg_… will be better name ?

Kirill_ASKorinskiy · March 25, 2009, 7:35pm

At Wed, 25 Mar 2009 20:19:11 +0300,
Igor S. [email protected] wrote:

On Wed, Mar 25, 2009 at 08:15:33PM +0300, Kirill A. Korinskiy wrote:

Raw value of arguments from request string can help for XSS.

Probably, $encoded_arg_… will be better name ?

I’m not sure. If you sure – i can change patch

Kirill_ASKorinskiy · March 25, 2009, 7:43pm

Hello!

On Wed, Mar 25, 2009 at 09:26:09PM +0300, Kirill A. Korinskiy wrote:

I’m not sure. If you sure – i can change patch
I am. By using $arg_encode_* you basically disable encode_*
arguments.

Maxim D.

Kirill_ASKorinskiy · March 25, 2009, 8:08pm

Raw value of arguments from request string can help for XSS.

src/http/ngx_http_variables.c | 54
+++++++++++++++++++++++++++++++++++++++++
1 files changed, 54 insertions(+), 0 deletions(-)

diff --git a/src/http/ngx_http_variables.c
b/src/http/ngx_http_variables.c
index
22f213cf6157ab5b99e481835acf9a394ef21919…c8990ac7d283020835547be71f05b55a940152f3
100644
— a/src/http/ngx_http_variables.c
+++ b/src/http/ngx_http_variables.c
@@ -31,6 +31,8 @@ static ngx_int_t
ngx_http_variable_cookie(ngx_http_request_t *r,
static ngx_int_t ngx_http_variable_ssi(ngx_http_request_t *r,
ngx_http_variable_value_t *v, uintptr_t data);
#endif
+static ngx_int_t ngx_http_variable_encoded_argument(ngx_http_request_t
*r,

ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_argument(ngx_http_request_t *r,
ngx_http_variable_value_t *v, uintptr_t data);

@@ -530,6 +532,15 @@ ngx_http_get_variable(ngx_http_request_t *r,
ngx_str_t *name, ngx_uint_t key,
}
#endif

if (ngx_strncmp(name->data, “encoded_arg_”, 12) == 0) {

   if (ngx_http_variable_encoded_argument(r, vv, (uintptr_t) name)

== NGX_OK) {

```
       return vv;
```
```
   }
```
```
   return NULL;
```
}

if (ngx_strncmp(name->data, “arg_”, 4) == 0) {

   if (ngx_http_variable_argument(r, vv, (uintptr_t) name) ==

NGX_OK) {
@@ -831,6 +842,42 @@ ngx_http_variable_ssi(ngx_http_request_t *r,
ngx_http_variable_value_t *v,

static ngx_int_t
+ngx_http_variable_encoded_argument(ngx_http_request_t *r,
ngx_http_variable_value_t *v,

uintptr_t data)
+{
ngx_str_t *name = (ngx_str_t *) data;
u_char *arg;
size_t len;
ngx_str_t value;
len = name->len - (sizeof(“encoded_arg_”) - 1);
arg = name->data + sizeof(“encoded_arg_”) - 1;
if (ngx_http_arg(r, arg, len, &value) != NGX_OK) {
```
   v->not_found = 1;
```
```
   return NGX_OK;
```
}
v->len = value.len +
2 * ngx_escape_uri(NULL, value.data, value.len, NGX_ESCAPE_ARGS);
v->data = ngx_palloc(r->pool, v->len);
if (v->data == NULL) {
```
   v->not_found = 1;
```
```
   return NGX_OK;
```
}
(void) ngx_escape_uri(v->data, value.data, value.len,
NGX_ESCAPE_ARGS);
v->valid = 1;
v->no_cacheable = 0;
v->not_found = 0;
return NGX_OK;
+}

+static ngx_int_t
ngx_http_variable_argument(ngx_http_request_t *r,
ngx_http_variable_value_t *v,
uintptr_t data)
{
@@ -1789,6 +1836,13 @@ ngx_http_variables_init_vars(ngx_conf_t *cf)
}
#endif

   if (ngx_strncmp(v[i].name.data, "encoded_arg_", 12) == 0) {

       v[i].get_handler = ngx_http_variable_encoded_argument;

       v[i].data = (uintptr_t) &v[i].name;

```
       continue;
```
```
   }
```

   if (ngx_strncmp(v[i].name.data, "arg_", 4) == 0) {
       v[i].get_handler = ngx_http_variable_argument;
       v[i].data = (uintptr_t) &v[i].name;