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ngx_http_auth_digest_module.h
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ngx_http_auth_digest_module.h
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#ifndef _NGX_HTTP_AUTH_DIGEST_H_INCLUDED_
#define _NGX_HTTP_AUTH_DIGEST_H_INCLUDED_
#define NGX_HTTP_AUTH_DIGEST_USERNOTFOUND 1000
// the module conf
typedef struct {
ngx_http_complex_value_t realm;
time_t timeout;
time_t expires;
time_t drop_time;
time_t evasion_time;
ngx_int_t replays;
ngx_int_t maxtries;
ngx_http_complex_value_t user_file;
ngx_str_t cache_dir;
} ngx_http_auth_digest_loc_conf_t;
// contents of the request's authorization header
typedef struct {
ngx_str_t auth_scheme;
ngx_str_t username;
ngx_str_t realm;
ngx_str_t nonce;
ngx_str_t nc;
ngx_str_t uri;
ngx_str_t qop;
ngx_str_t cnonce;
ngx_str_t response;
ngx_str_t opaque;
ngx_int_t stale;
} ngx_http_auth_digest_cred_t;
// the nonce as an issue-time/random-num pair
typedef struct {
ngx_uint_t rnd;
time_t t;
} ngx_http_auth_digest_nonce_t;
// nonce entries in the rbtree
typedef struct {
ngx_rbtree_node_t node; // the node's .key is derived from the nonce val
time_t expires; // time at which the node should be evicted
time_t drop_time;
char nc[0]; // bitvector of used nc values to prevent replays
} ngx_http_auth_digest_node_t;
// evasion entries in the rbtree
typedef struct {
ngx_rbtree_node_t node; // the node's .key is derived from the source address
time_t drop_time;
ngx_int_t failcount;
struct sockaddr src_addr;
socklen_t src_addrlen;
} ngx_http_auth_digest_ev_node_t;
// the main event
static ngx_int_t ngx_http_auth_digest_handler(ngx_http_request_t *r);
// realm handling
static char *ngx_http_auth_digest_set_realm(ngx_conf_t *cf, ngx_command_t *cmd,
void *conf);
// passwd file handling
static void ngx_http_auth_digest_close(ngx_file_t *file);
static char *ngx_http_auth_digest_set_user_file(ngx_conf_t *cf,
ngx_command_t *cmd, void *conf);
#define NGX_HTTP_AUTH_DIGEST_BUF_SIZE 4096
// digest challenge generation
static ngx_int_t ngx_http_auth_digest_send_challenge(ngx_http_request_t *r,
ngx_str_t *realm,
ngx_uint_t is_stale);
// digest response validators
static ngx_int_t
ngx_http_auth_digest_check_credentials(ngx_http_request_t *r,
ngx_http_auth_digest_cred_t *ctx);
static ngx_int_t
ngx_http_auth_digest_verify_user(ngx_http_request_t *r,
ngx_http_auth_digest_cred_t *fields,
ngx_str_t *line);
static ngx_int_t
ngx_http_auth_digest_verify_hash(ngx_http_request_t *r,
ngx_http_auth_digest_cred_t *fields,
u_char *hashed_pw);
// the shm segment that houses the used-nonces tree and evasion rbtree
static ngx_uint_t ngx_http_auth_digest_shm_size;
static ngx_shm_zone_t *ngx_http_auth_digest_shm_zone;
static ngx_rbtree_t *ngx_http_auth_digest_rbtree;
static ngx_rbtree_t *ngx_http_auth_digest_ev_rbtree;
static char *ngx_http_auth_digest_set_shm_size(ngx_conf_t *cf,
ngx_command_t *cmd, void *conf);
static ngx_int_t ngx_http_auth_digest_init_shm_zone(ngx_shm_zone_t *shm_zone,
void *data);
// nonce bookkeeping
static ngx_http_auth_digest_nonce_t
ngx_http_auth_digest_next_nonce(ngx_http_request_t *r);
static ngx_rbtree_node_t *
ngx_http_auth_digest_rbtree_find(ngx_rbtree_key_t key, ngx_rbtree_node_t *node,
ngx_rbtree_node_t *sentinel);
// nonce cleanup
#define NGX_HTTP_AUTH_DIGEST_CLEANUP_INTERVAL 3000
#define NGX_HTTP_AUTH_DIGEST_CLEANUP_BATCH_SIZE 2048
ngx_event_t *ngx_http_auth_digest_cleanup_timer;
static ngx_array_t *ngx_http_auth_digest_cleanup_list;
static ngx_atomic_t *ngx_http_auth_digest_cleanup_lock;
void ngx_http_auth_digest_cleanup(ngx_event_t *e);
static void ngx_http_auth_digest_rbtree_prune(ngx_log_t *log);
static void ngx_http_auth_digest_rbtree_prune_walk(ngx_rbtree_node_t *node,
ngx_rbtree_node_t *sentinel,
time_t now, ngx_log_t *log);
static void ngx_http_auth_digest_ev_rbtree_prune(ngx_log_t *log);
static void
ngx_http_auth_digest_ev_rbtree_prune_walk(ngx_rbtree_node_t *node,
ngx_rbtree_node_t *sentinel,
time_t now, ngx_log_t *log);
// evasive tactics functions
static int ngx_http_auth_digest_srcaddr_key(struct sockaddr *sa, socklen_t len,
ngx_uint_t *key);
static int ngx_http_auth_digest_srcaddr_cmp(struct sockaddr *sa1,
socklen_t len1,
struct sockaddr *sa2,
socklen_t len2);
static ngx_http_auth_digest_ev_node_t *
ngx_http_auth_digest_ev_rbtree_find(ngx_http_auth_digest_ev_node_t *this,
ngx_rbtree_node_t *node,
ngx_rbtree_node_t *sentinel);
#define NGX_HTTP_AUTH_DIGEST_STATUS_SUCCESS 1
#define NGX_HTTP_AUTH_DIGEST_STATUS_FAILURE 0
static void
ngx_http_auth_digest_evasion_tracking(ngx_http_request_t *r,
ngx_http_auth_digest_loc_conf_t *alcf,
ngx_int_t status);
static int ngx_http_auth_digest_evading(ngx_http_request_t *r,
ngx_http_auth_digest_loc_conf_t *alcf);
// rbtree primitives
static void ngx_http_auth_digest_rbtree_insert(ngx_rbtree_node_t *temp,
ngx_rbtree_node_t *node,
ngx_rbtree_node_t *sentinel);
static void ngx_http_auth_digest_ev_rbtree_insert(ngx_rbtree_node_t *temp,
ngx_rbtree_node_t *node,
ngx_rbtree_node_t *sentinel);
static void
ngx_rbtree_generic_insert(ngx_rbtree_node_t *temp, ngx_rbtree_node_t *node,
ngx_rbtree_node_t *sentinel,
int (*compare)(const ngx_rbtree_node_t *left,
const ngx_rbtree_node_t *right));
static int ngx_http_auth_digest_rbtree_cmp(const ngx_rbtree_node_t *v_left,
const ngx_rbtree_node_t *v_right);
// quick & dirty bitvectors (for marking used nc values)
static ngx_inline ngx_uint_t ngx_bitvector_size(ngx_uint_t nbits) {
return ((nbits + CHAR_BIT - 1) / CHAR_BIT);
}
static ngx_inline ngx_uint_t ngx_bitvector_test(char *bv, ngx_uint_t bit) {
return ((bv)[((bit) / CHAR_BIT)] & (1 << ((bit) % CHAR_BIT)));
}
static ngx_inline void ngx_bitvector_set(char *bv, ngx_uint_t bit) {
((bv)[((bit) / CHAR_BIT)] &= ~(1 << ((bit) % CHAR_BIT)));
}
// module plumbing
static void *ngx_http_auth_digest_create_loc_conf(ngx_conf_t *cf);
static char *ngx_http_auth_digest_merge_loc_conf(ngx_conf_t *cf, void *parent,
void *child);
static ngx_int_t ngx_http_auth_digest_init(ngx_conf_t *cf);
static ngx_int_t ngx_http_auth_digest_worker_init(ngx_cycle_t *cycle);
// module datastructures
static ngx_command_t ngx_http_auth_digest_commands[] = {
{ngx_string("auth_digest"),
NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF | NGX_HTTP_LOC_CONF |
NGX_HTTP_LMT_CONF | NGX_CONF_TAKE1,
ngx_http_auth_digest_set_realm, NGX_HTTP_LOC_CONF_OFFSET,
offsetof(ngx_http_auth_digest_loc_conf_t, realm), NULL},
{ngx_string("auth_digest_user_file"),
NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF | NGX_HTTP_LOC_CONF |
NGX_HTTP_LMT_CONF | NGX_CONF_TAKE1,
ngx_http_auth_digest_set_user_file, NGX_HTTP_LOC_CONF_OFFSET,
offsetof(ngx_http_auth_digest_loc_conf_t, user_file), NULL},
{ngx_string("auth_digest_timeout"), NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF |
NGX_HTTP_LOC_CONF | NGX_CONF_TAKE1,
ngx_conf_set_sec_slot, NGX_HTTP_LOC_CONF_OFFSET,
offsetof(ngx_http_auth_digest_loc_conf_t, timeout), NULL},
{ngx_string("auth_digest_expires"), NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF |
NGX_HTTP_LOC_CONF | NGX_CONF_TAKE1,
ngx_conf_set_sec_slot, NGX_HTTP_LOC_CONF_OFFSET,
offsetof(ngx_http_auth_digest_loc_conf_t, expires), NULL},
{ngx_string("auth_digest_drop_time"),
NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF | NGX_HTTP_LOC_CONF |
NGX_CONF_TAKE1,
ngx_conf_set_sec_slot, NGX_HTTP_LOC_CONF_OFFSET,
offsetof(ngx_http_auth_digest_loc_conf_t, drop_time), NULL},
{ngx_string("auth_digest_evasion_time"),
NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF | NGX_HTTP_LOC_CONF |
NGX_CONF_TAKE1,
ngx_conf_set_sec_slot, NGX_HTTP_LOC_CONF_OFFSET,
offsetof(ngx_http_auth_digest_loc_conf_t, evasion_time), NULL},
{ngx_string("auth_digest_replays"), NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF |
NGX_HTTP_LOC_CONF | NGX_CONF_TAKE1,
ngx_conf_set_num_slot, NGX_HTTP_LOC_CONF_OFFSET,
offsetof(ngx_http_auth_digest_loc_conf_t, replays), NULL},
{ngx_string("auth_digest_maxtries"),
NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF | NGX_HTTP_LOC_CONF |
NGX_CONF_TAKE1,
ngx_conf_set_num_slot, NGX_HTTP_LOC_CONF_OFFSET,
offsetof(ngx_http_auth_digest_loc_conf_t, maxtries), NULL},
{ngx_string("auth_digest_shm_size"),
NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF | NGX_CONF_TAKE1,
ngx_http_auth_digest_set_shm_size, 0, 0, NULL},
ngx_null_command};
static ngx_http_module_t ngx_http_auth_digest_module_ctx = {
NULL, /* preconfiguration */
ngx_http_auth_digest_init, /* postconfiguration */
NULL, /* create main configuration */
NULL, /* init main configuration */
NULL, /* create server configuration */
NULL, /* merge server configuration */
ngx_http_auth_digest_create_loc_conf, /* create location configuration */
ngx_http_auth_digest_merge_loc_conf /* merge location configuration */
};
ngx_module_t ngx_http_auth_digest_module = {
NGX_MODULE_V1,
&ngx_http_auth_digest_module_ctx, /* module context */
ngx_http_auth_digest_commands, /* module directives */
NGX_HTTP_MODULE, /* module type */
NULL, /* init master */
NULL, /* init module */
ngx_http_auth_digest_worker_init, /* init process */
NULL, /* init thread */
NULL, /* exit thread */
NULL, /* exit process */
NULL, /* exit master */
NGX_MODULE_V1_PADDING};
#endif