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view src/http/modules/ngx_http_upstream_random_module.c @ 7629:f47f7d3d1bfa

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Mp4: fixed possible chunk offset overflow. In "co64" atom chunk start offset is a 64-bit unsigned integer. When trimming the "mdat" atom, chunk offsets are casted to off_t values which are typically 64-bit signed integers. A specially crafted mp4 file with huge chunk offsets may lead to off_t overflow and result in negative trim boundaries. The consequences of the overflow are: - Incorrect Content-Length header value in the response. - Negative left boundary of the response file buffer holding the trimmed "mdat". This leads to pread()/sendfile() errors followed by closing the client connection. On rare systems where off_t is a 32-bit integer, this scenario is also feasible with the "stco" atom. The fix is to add checks which make sure data chunks referenced by each track are within the mp4 file boundaries. Additionally a few more checks are added to ensure mp4 file consistency and log errors.
author Roman Arutyunyan <arut@nginx.com>
date Wed, 26 Feb 2020 15:10:46 +0300
parents f2396ecf608b
children
line wrap: on
line source


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


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


typedef struct {
    ngx_http_upstream_rr_peer_t          *peer;
    ngx_uint_t                            range;
} ngx_http_upstream_random_range_t;


typedef struct {
    ngx_uint_t                            two;
    ngx_http_upstream_random_range_t     *ranges;
} ngx_http_upstream_random_srv_conf_t;


typedef struct {
    /* the round robin data must be first */
    ngx_http_upstream_rr_peer_data_t      rrp;

    ngx_http_upstream_random_srv_conf_t  *conf;
    u_char                                tries;
} ngx_http_upstream_random_peer_data_t;


static ngx_int_t ngx_http_upstream_init_random(ngx_conf_t *cf,
    ngx_http_upstream_srv_conf_t *us);
static ngx_int_t ngx_http_upstream_update_random(ngx_pool_t *pool,
    ngx_http_upstream_srv_conf_t *us);

static ngx_int_t ngx_http_upstream_init_random_peer(ngx_http_request_t *r,
    ngx_http_upstream_srv_conf_t *us);
static ngx_int_t ngx_http_upstream_get_random_peer(ngx_peer_connection_t *pc,
    void *data);
static ngx_int_t ngx_http_upstream_get_random2_peer(ngx_peer_connection_t *pc,
    void *data);
static ngx_uint_t ngx_http_upstream_peek_random_peer(
    ngx_http_upstream_rr_peers_t *peers,
    ngx_http_upstream_random_peer_data_t *rp);
static void *ngx_http_upstream_random_create_conf(ngx_conf_t *cf);
static char *ngx_http_upstream_random(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);


static ngx_command_t  ngx_http_upstream_random_commands[] = {

    { ngx_string("random"),
      NGX_HTTP_UPS_CONF|NGX_CONF_NOARGS|NGX_CONF_TAKE12,
      ngx_http_upstream_random,
      NGX_HTTP_SRV_CONF_OFFSET,
      0,
      NULL },

      ngx_null_command
};


static ngx_http_module_t  ngx_http_upstream_random_module_ctx = {
    NULL,                                  /* preconfiguration */
    NULL,                                  /* postconfiguration */

    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

    ngx_http_upstream_random_create_conf,  /* create server configuration */
    NULL,                                  /* merge server configuration */

    NULL,                                  /* create location configuration */
    NULL                                   /* merge location configuration */
};


ngx_module_t  ngx_http_upstream_random_module = {
    NGX_MODULE_V1,
    &ngx_http_upstream_random_module_ctx,  /* module context */
    ngx_http_upstream_random_commands,     /* module directives */
    NGX_HTTP_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


static ngx_int_t
ngx_http_upstream_init_random(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us)
{
    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, cf->log, 0, "init random");

    if (ngx_http_upstream_init_round_robin(cf, us) != NGX_OK) {
        return NGX_ERROR;
    }

    us->peer.init = ngx_http_upstream_init_random_peer;

#if (NGX_HTTP_UPSTREAM_ZONE)
    if (us->shm_zone) {
        return NGX_OK;
    }
#endif

    return ngx_http_upstream_update_random(cf->pool, us);
}


static ngx_int_t
ngx_http_upstream_update_random(ngx_pool_t *pool,
    ngx_http_upstream_srv_conf_t *us)
{
    size_t                                size;
    ngx_uint_t                            i, total_weight;
    ngx_http_upstream_rr_peer_t          *peer;
    ngx_http_upstream_rr_peers_t         *peers;
    ngx_http_upstream_random_range_t     *ranges;
    ngx_http_upstream_random_srv_conf_t  *rcf;

    rcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_random_module);

    peers = us->peer.data;

    size = peers->number * sizeof(ngx_http_upstream_random_range_t);

    ranges = pool ? ngx_palloc(pool, size) : ngx_alloc(size, ngx_cycle->log);
    if (ranges == NULL) {
        return NGX_ERROR;
    }

    total_weight = 0;

    for (peer = peers->peer, i = 0; peer; peer = peer->next, i++) {
        ranges[i].peer = peer;
        ranges[i].range = total_weight;
        total_weight += peer->weight;
    }

    rcf->ranges = ranges;

    return NGX_OK;
}


static ngx_int_t
ngx_http_upstream_init_random_peer(ngx_http_request_t *r,
    ngx_http_upstream_srv_conf_t *us)
{
    ngx_http_upstream_random_srv_conf_t   *rcf;
    ngx_http_upstream_random_peer_data_t  *rp;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "init random peer");

    rcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_random_module);

    rp = ngx_palloc(r->pool, sizeof(ngx_http_upstream_random_peer_data_t));
    if (rp == NULL) {
        return NGX_ERROR;
    }

    r->upstream->peer.data = &rp->rrp;

    if (ngx_http_upstream_init_round_robin_peer(r, us) != NGX_OK) {
        return NGX_ERROR;
    }

    if (rcf->two) {
        r->upstream->peer.get = ngx_http_upstream_get_random2_peer;

    } else {
        r->upstream->peer.get = ngx_http_upstream_get_random_peer;
    }

    rp->conf = rcf;
    rp->tries = 0;

    ngx_http_upstream_rr_peers_rlock(rp->rrp.peers);

#if (NGX_HTTP_UPSTREAM_ZONE)
    if (rp->rrp.peers->shpool && rcf->ranges == NULL) {
        if (ngx_http_upstream_update_random(NULL, us) != NGX_OK) {
            ngx_http_upstream_rr_peers_unlock(rp->rrp.peers);
            return NGX_ERROR;
        }
    }
#endif

    ngx_http_upstream_rr_peers_unlock(rp->rrp.peers);

    return NGX_OK;
}


static ngx_int_t
ngx_http_upstream_get_random_peer(ngx_peer_connection_t *pc, void *data)
{
    ngx_http_upstream_random_peer_data_t  *rp = data;

    time_t                             now;
    uintptr_t                          m;
    ngx_uint_t                         i, n;
    ngx_http_upstream_rr_peer_t       *peer;
    ngx_http_upstream_rr_peers_t      *peers;
    ngx_http_upstream_rr_peer_data_t  *rrp;

    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0,
                   "get random peer, try: %ui", pc->tries);

    rrp = &rp->rrp;
    peers = rrp->peers;

    ngx_http_upstream_rr_peers_rlock(peers);

    if (rp->tries > 20 || peers->single) {
        ngx_http_upstream_rr_peers_unlock(peers);
        return ngx_http_upstream_get_round_robin_peer(pc, rrp);
    }

    pc->cached = 0;
    pc->connection = NULL;

    now = ngx_time();

    for ( ;; ) {

        i = ngx_http_upstream_peek_random_peer(peers, rp);

        peer = rp->conf->ranges[i].peer;

        n = i / (8 * sizeof(uintptr_t));
        m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t));

        if (rrp->tried[n] & m) {
            goto next;
        }

        ngx_http_upstream_rr_peer_lock(peers, peer);

        if (peer->down) {
            ngx_http_upstream_rr_peer_unlock(peers, peer);
            goto next;
        }

        if (peer->max_fails
            && peer->fails >= peer->max_fails
            && now - peer->checked <= peer->fail_timeout)
        {
            ngx_http_upstream_rr_peer_unlock(peers, peer);
            goto next;
        }

        if (peer->max_conns && peer->conns >= peer->max_conns) {
            ngx_http_upstream_rr_peer_unlock(peers, peer);
            goto next;
        }

        break;

    next:

        if (++rp->tries > 20) {
            ngx_http_upstream_rr_peers_unlock(peers);
            return ngx_http_upstream_get_round_robin_peer(pc, rrp);
        }
    }

    rrp->current = peer;

    if (now - peer->checked > peer->fail_timeout) {
        peer->checked = now;
    }

    pc->sockaddr = peer->sockaddr;
    pc->socklen = peer->socklen;
    pc->name = &peer->name;

    peer->conns++;

    ngx_http_upstream_rr_peer_unlock(peers, peer);
    ngx_http_upstream_rr_peers_unlock(peers);

    rrp->tried[n] |= m;

    return NGX_OK;
}


static ngx_int_t
ngx_http_upstream_get_random2_peer(ngx_peer_connection_t *pc, void *data)
{
    ngx_http_upstream_random_peer_data_t  *rp = data;

    time_t                             now;
    uintptr_t                          m;
    ngx_uint_t                         i, n, p;
    ngx_http_upstream_rr_peer_t       *peer, *prev;
    ngx_http_upstream_rr_peers_t      *peers;
    ngx_http_upstream_rr_peer_data_t  *rrp;

    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0,
                   "get random2 peer, try: %ui", pc->tries);

    rrp = &rp->rrp;
    peers = rrp->peers;

    ngx_http_upstream_rr_peers_wlock(peers);

    if (rp->tries > 20 || peers->single) {
        ngx_http_upstream_rr_peers_unlock(peers);
        return ngx_http_upstream_get_round_robin_peer(pc, rrp);
    }

    pc->cached = 0;
    pc->connection = NULL;

    now = ngx_time();

    prev = NULL;

#if (NGX_SUPPRESS_WARN)
    p = 0;
#endif

    for ( ;; ) {

        i = ngx_http_upstream_peek_random_peer(peers, rp);

        peer = rp->conf->ranges[i].peer;

        if (peer == prev) {
            goto next;
        }

        n = i / (8 * sizeof(uintptr_t));
        m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t));

        if (rrp->tried[n] & m) {
            goto next;
        }

        if (peer->down) {
            goto next;
        }

        if (peer->max_fails
            && peer->fails >= peer->max_fails
            && now - peer->checked <= peer->fail_timeout)
        {
            goto next;
        }

        if (peer->max_conns && peer->conns >= peer->max_conns) {
            goto next;
        }

        if (prev) {
            if (peer->conns * prev->weight > prev->conns * peer->weight) {
                peer = prev;
                n = p / (8 * sizeof(uintptr_t));
                m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t));
            }

            break;
        }

        prev = peer;
        p = i;

    next:

        if (++rp->tries > 20) {
            ngx_http_upstream_rr_peers_unlock(peers);
            return ngx_http_upstream_get_round_robin_peer(pc, rrp);
        }
    }

    rrp->current = peer;

    if (now - peer->checked > peer->fail_timeout) {
        peer->checked = now;
    }

    pc->sockaddr = peer->sockaddr;
    pc->socklen = peer->socklen;
    pc->name = &peer->name;

    peer->conns++;

    ngx_http_upstream_rr_peers_unlock(peers);

    rrp->tried[n] |= m;

    return NGX_OK;
}


static ngx_uint_t
ngx_http_upstream_peek_random_peer(ngx_http_upstream_rr_peers_t *peers,
    ngx_http_upstream_random_peer_data_t *rp)
{
    ngx_uint_t  i, j, k, x;

    x = ngx_random() % peers->total_weight;

    i = 0;
    j = peers->number;

    while (j - i > 1) {
        k = (i + j) / 2;

        if (x < rp->conf->ranges[k].range) {
            j = k;

        } else {
            i = k;
        }
    }

    return i;
}


static void *
ngx_http_upstream_random_create_conf(ngx_conf_t *cf)
{
    ngx_http_upstream_random_srv_conf_t  *conf;

    conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_upstream_random_srv_conf_t));
    if (conf == NULL) {
        return NULL;
    }

    /*
     * set by ngx_pcalloc():
     *
     *     conf->two = 0;
     */

    return conf;
}


static char *
ngx_http_upstream_random(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_upstream_random_srv_conf_t  *rcf = conf;

    ngx_str_t                     *value;
    ngx_http_upstream_srv_conf_t  *uscf;

    uscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_upstream_module);

    if (uscf->peer.init_upstream) {
        ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
                           "load balancing method redefined");
    }

    uscf->peer.init_upstream = ngx_http_upstream_init_random;

    uscf->flags = NGX_HTTP_UPSTREAM_CREATE
                  |NGX_HTTP_UPSTREAM_WEIGHT
                  |NGX_HTTP_UPSTREAM_MAX_CONNS
                  |NGX_HTTP_UPSTREAM_MAX_FAILS
                  |NGX_HTTP_UPSTREAM_FAIL_TIMEOUT
                  |NGX_HTTP_UPSTREAM_DOWN;

    if (cf->args->nelts == 1) {
        return NGX_CONF_OK;
    }

    value = cf->args->elts;

    if (ngx_strcmp(value[1].data, "two") == 0) {
        rcf->two = 1;

    } else {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "invalid parameter \"%V\"", &value[1]);
        return NGX_CONF_ERROR;
    }

    if (cf->args->nelts == 2) {
        return NGX_CONF_OK;
    }

    if (ngx_strcmp(value[2].data, "least_conn") != 0) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "invalid parameter \"%V\"", &value[2]);
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}