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view src/http/ngx_http_upstream_round_robin.h @ 8164:b71e69247483

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Variables: avoid possible buffer overrun with some "$sent_http_*". The existing logic to evaluate multi header "$sent_http_*" variables, such as $sent_http_cache_control, as previously introduced in 1.23.0, doesn't take into account that one or more elements can be cleared, yet still present in a linked list, pointed to by the next field. Such elements don't contribute to the resulting variable length, an attempt to append a separator for them ends up in out of bounds write. This is not possible with standard modules, though at least one third party module is known to override multi header values this way, so it makes sense to harden the logic. The fix restores a generic boundary check.
author Sergey Kandaurov <pluknet@nginx.com>
date Mon, 01 May 2023 19:16:05 +0400
parents 90cc7194e993
children
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_HTTP_UPSTREAM_ROUND_ROBIN_H_INCLUDED_
#define _NGX_HTTP_UPSTREAM_ROUND_ROBIN_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>


typedef struct ngx_http_upstream_rr_peer_s   ngx_http_upstream_rr_peer_t;

struct ngx_http_upstream_rr_peer_s {
    struct sockaddr                *sockaddr;
    socklen_t                       socklen;
    ngx_str_t                       name;
    ngx_str_t                       server;

    ngx_int_t                       current_weight;
    ngx_int_t                       effective_weight;
    ngx_int_t                       weight;

    ngx_uint_t                      conns;
    ngx_uint_t                      max_conns;

    ngx_uint_t                      fails;
    time_t                          accessed;
    time_t                          checked;

    ngx_uint_t                      max_fails;
    time_t                          fail_timeout;
    ngx_msec_t                      slow_start;
    ngx_msec_t                      start_time;

    ngx_uint_t                      down;

#if (NGX_HTTP_SSL || NGX_COMPAT)
    void                           *ssl_session;
    int                             ssl_session_len;
#endif

#if (NGX_HTTP_UPSTREAM_ZONE)
    ngx_atomic_t                    lock;
#endif

    ngx_http_upstream_rr_peer_t    *next;

    NGX_COMPAT_BEGIN(32)
    NGX_COMPAT_END
};


typedef struct ngx_http_upstream_rr_peers_s  ngx_http_upstream_rr_peers_t;

struct ngx_http_upstream_rr_peers_s {
    ngx_uint_t                      number;

#if (NGX_HTTP_UPSTREAM_ZONE)
    ngx_slab_pool_t                *shpool;
    ngx_atomic_t                    rwlock;
    ngx_http_upstream_rr_peers_t   *zone_next;
#endif

    ngx_uint_t                      total_weight;
    ngx_uint_t                      tries;

    unsigned                        single:1;
    unsigned                        weighted:1;

    ngx_str_t                      *name;

    ngx_http_upstream_rr_peers_t   *next;

    ngx_http_upstream_rr_peer_t    *peer;
};


#if (NGX_HTTP_UPSTREAM_ZONE)

#define ngx_http_upstream_rr_peers_rlock(peers)                               \
                                                                              \
    if (peers->shpool) {                                                      \
        ngx_rwlock_rlock(&peers->rwlock);                                     \
    }

#define ngx_http_upstream_rr_peers_wlock(peers)                               \
                                                                              \
    if (peers->shpool) {                                                      \
        ngx_rwlock_wlock(&peers->rwlock);                                     \
    }

#define ngx_http_upstream_rr_peers_unlock(peers)                              \
                                                                              \
    if (peers->shpool) {                                                      \
        ngx_rwlock_unlock(&peers->rwlock);                                    \
    }


#define ngx_http_upstream_rr_peer_lock(peers, peer)                           \
                                                                              \
    if (peers->shpool) {                                                      \
        ngx_rwlock_wlock(&peer->lock);                                        \
    }

#define ngx_http_upstream_rr_peer_unlock(peers, peer)                         \
                                                                              \
    if (peers->shpool) {                                                      \
        ngx_rwlock_unlock(&peer->lock);                                       \
    }

#else

#define ngx_http_upstream_rr_peers_rlock(peers)
#define ngx_http_upstream_rr_peers_wlock(peers)
#define ngx_http_upstream_rr_peers_unlock(peers)
#define ngx_http_upstream_rr_peer_lock(peers, peer)
#define ngx_http_upstream_rr_peer_unlock(peers, peer)

#endif


typedef struct {
    ngx_uint_t                      config;
    ngx_http_upstream_rr_peers_t   *peers;
    ngx_http_upstream_rr_peer_t    *current;
    uintptr_t                      *tried;
    uintptr_t                       data;
} ngx_http_upstream_rr_peer_data_t;


ngx_int_t ngx_http_upstream_init_round_robin(ngx_conf_t *cf,
    ngx_http_upstream_srv_conf_t *us);
ngx_int_t ngx_http_upstream_init_round_robin_peer(ngx_http_request_t *r,
    ngx_http_upstream_srv_conf_t *us);
ngx_int_t ngx_http_upstream_create_round_robin_peer(ngx_http_request_t *r,
    ngx_http_upstream_resolved_t *ur);
ngx_int_t ngx_http_upstream_get_round_robin_peer(ngx_peer_connection_t *pc,
    void *data);
void ngx_http_upstream_free_round_robin_peer(ngx_peer_connection_t *pc,
    void *data, ngx_uint_t state);

#if (NGX_HTTP_SSL)
ngx_int_t
    ngx_http_upstream_set_round_robin_peer_session(ngx_peer_connection_t *pc,
    void *data);
void ngx_http_upstream_save_round_robin_peer_session(ngx_peer_connection_t *pc,
    void *data);
#endif


#endif /* _NGX_HTTP_UPSTREAM_ROUND_ROBIN_H_INCLUDED_ */