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view src/stream/ngx_stream_access_module.c @ 9112:d59277dd3d8c

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QUIC: fixed post-close use-after-free. Previously, ngx_quic_close_connection() could be called in a way that QUIC connection was accessed after the call. In most cases the connection is not closed right away, but close timeout is scheduled. However, it's not always the case. Also, if the close process started earlier for a different reason, calling ngx_quic_close_connection() may actually close the connection. The connection object should not be accessed after that. Now, when possible, return statement is added to eliminate post-close connection object access. In other places ngx_quic_close_connection() is substituted with posting close event. Also, the new way of closing connection in ngx_quic_stream_cleanup_handler() fixes another problem in this function. Previously it passed stream connection instead of QUIC connection to ngx_quic_close_connection(). This could result in incomplete connection shutdown. One consequence of that could be that QUIC streams were freed without shutting down their application contexts. This could result in another use-after-free. Found by Coverity (CID 1530402).
author Roman Arutyunyan <arut@nginx.com>
date Mon, 22 May 2023 15:59:42 +0400
parents 72188d1bcab5
children
line wrap: on
line source


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


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


typedef struct {
    in_addr_t         mask;
    in_addr_t         addr;
    ngx_uint_t        deny;      /* unsigned  deny:1; */
} ngx_stream_access_rule_t;

#if (NGX_HAVE_INET6)

typedef struct {
    struct in6_addr   addr;
    struct in6_addr   mask;
    ngx_uint_t        deny;      /* unsigned  deny:1; */
} ngx_stream_access_rule6_t;

#endif

#if (NGX_HAVE_UNIX_DOMAIN)

typedef struct {
    ngx_uint_t        deny;      /* unsigned  deny:1; */
} ngx_stream_access_rule_un_t;

#endif

typedef struct {
    ngx_array_t      *rules;     /* array of ngx_stream_access_rule_t */
#if (NGX_HAVE_INET6)
    ngx_array_t      *rules6;    /* array of ngx_stream_access_rule6_t */
#endif
#if (NGX_HAVE_UNIX_DOMAIN)
    ngx_array_t      *rules_un;  /* array of ngx_stream_access_rule_un_t */
#endif
} ngx_stream_access_srv_conf_t;


static ngx_int_t ngx_stream_access_handler(ngx_stream_session_t *s);
static ngx_int_t ngx_stream_access_inet(ngx_stream_session_t *s,
    ngx_stream_access_srv_conf_t *ascf, in_addr_t addr);
#if (NGX_HAVE_INET6)
static ngx_int_t ngx_stream_access_inet6(ngx_stream_session_t *s,
    ngx_stream_access_srv_conf_t *ascf, u_char *p);
#endif
#if (NGX_HAVE_UNIX_DOMAIN)
static ngx_int_t ngx_stream_access_unix(ngx_stream_session_t *s,
    ngx_stream_access_srv_conf_t *ascf);
#endif
static ngx_int_t ngx_stream_access_found(ngx_stream_session_t *s,
    ngx_uint_t deny);
static char *ngx_stream_access_rule(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static void *ngx_stream_access_create_srv_conf(ngx_conf_t *cf);
static char *ngx_stream_access_merge_srv_conf(ngx_conf_t *cf,
    void *parent, void *child);
static ngx_int_t ngx_stream_access_init(ngx_conf_t *cf);


static ngx_command_t  ngx_stream_access_commands[] = {

    { ngx_string("allow"),
      NGX_STREAM_MAIN_CONF|NGX_STREAM_SRV_CONF|NGX_CONF_TAKE1,
      ngx_stream_access_rule,
      NGX_STREAM_SRV_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("deny"),
      NGX_STREAM_MAIN_CONF|NGX_STREAM_SRV_CONF|NGX_CONF_TAKE1,
      ngx_stream_access_rule,
      NGX_STREAM_SRV_CONF_OFFSET,
      0,
      NULL },

      ngx_null_command
};



static ngx_stream_module_t  ngx_stream_access_module_ctx = {
    NULL,                                  /* preconfiguration */
    ngx_stream_access_init,                /* postconfiguration */

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

    ngx_stream_access_create_srv_conf,     /* create server configuration */
    ngx_stream_access_merge_srv_conf       /* merge server configuration */
};


ngx_module_t  ngx_stream_access_module = {
    NGX_MODULE_V1,
    &ngx_stream_access_module_ctx,         /* module context */
    ngx_stream_access_commands,            /* module directives */
    NGX_STREAM_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_stream_access_handler(ngx_stream_session_t *s)
{
    struct sockaddr_in            *sin;
    ngx_stream_access_srv_conf_t  *ascf;
#if (NGX_HAVE_INET6)
    u_char                        *p;
    in_addr_t                      addr;
    struct sockaddr_in6           *sin6;
#endif

    ascf = ngx_stream_get_module_srv_conf(s, ngx_stream_access_module);

    switch (s->connection->sockaddr->sa_family) {

    case AF_INET:
        if (ascf->rules) {
            sin = (struct sockaddr_in *) s->connection->sockaddr;
            return ngx_stream_access_inet(s, ascf, sin->sin_addr.s_addr);
        }
        break;

#if (NGX_HAVE_INET6)

    case AF_INET6:
        sin6 = (struct sockaddr_in6 *) s->connection->sockaddr;
        p = sin6->sin6_addr.s6_addr;

        if (ascf->rules && IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
            addr = p[12] << 24;
            addr += p[13] << 16;
            addr += p[14] << 8;
            addr += p[15];
            return ngx_stream_access_inet(s, ascf, htonl(addr));
        }

        if (ascf->rules6) {
            return ngx_stream_access_inet6(s, ascf, p);
        }

        break;

#endif

#if (NGX_HAVE_UNIX_DOMAIN)

    case AF_UNIX:
        if (ascf->rules_un) {
            return ngx_stream_access_unix(s, ascf);
        }

        break;

#endif
    }

    return NGX_DECLINED;
}


static ngx_int_t
ngx_stream_access_inet(ngx_stream_session_t *s,
    ngx_stream_access_srv_conf_t *ascf, in_addr_t addr)
{
    ngx_uint_t                 i;
    ngx_stream_access_rule_t  *rule;

    rule = ascf->rules->elts;
    for (i = 0; i < ascf->rules->nelts; i++) {

        ngx_log_debug3(NGX_LOG_DEBUG_STREAM, s->connection->log, 0,
                       "access: %08XD %08XD %08XD",
                       addr, rule[i].mask, rule[i].addr);

        if ((addr & rule[i].mask) == rule[i].addr) {
            return ngx_stream_access_found(s, rule[i].deny);
        }
    }

    return NGX_DECLINED;
}


#if (NGX_HAVE_INET6)

static ngx_int_t
ngx_stream_access_inet6(ngx_stream_session_t *s,
    ngx_stream_access_srv_conf_t *ascf, u_char *p)
{
    ngx_uint_t                  n;
    ngx_uint_t                  i;
    ngx_stream_access_rule6_t  *rule6;

    rule6 = ascf->rules6->elts;
    for (i = 0; i < ascf->rules6->nelts; i++) {

#if (NGX_DEBUG)
        {
        size_t  cl, ml, al;
        u_char  ct[NGX_INET6_ADDRSTRLEN];
        u_char  mt[NGX_INET6_ADDRSTRLEN];
        u_char  at[NGX_INET6_ADDRSTRLEN];

        cl = ngx_inet6_ntop(p, ct, NGX_INET6_ADDRSTRLEN);
        ml = ngx_inet6_ntop(rule6[i].mask.s6_addr, mt, NGX_INET6_ADDRSTRLEN);
        al = ngx_inet6_ntop(rule6[i].addr.s6_addr, at, NGX_INET6_ADDRSTRLEN);

        ngx_log_debug6(NGX_LOG_DEBUG_STREAM, s->connection->log, 0,
                       "access: %*s %*s %*s", cl, ct, ml, mt, al, at);
        }
#endif

        for (n = 0; n < 16; n++) {
            if ((p[n] & rule6[i].mask.s6_addr[n]) != rule6[i].addr.s6_addr[n]) {
                goto next;
            }
        }

        return ngx_stream_access_found(s, rule6[i].deny);

    next:
        continue;
    }

    return NGX_DECLINED;
}

#endif


#if (NGX_HAVE_UNIX_DOMAIN)

static ngx_int_t
ngx_stream_access_unix(ngx_stream_session_t *s,
    ngx_stream_access_srv_conf_t *ascf)
{
    ngx_uint_t                    i;
    ngx_stream_access_rule_un_t  *rule_un;

    rule_un = ascf->rules_un->elts;
    for (i = 0; i < ascf->rules_un->nelts; i++) {

        /* TODO: check path */
        if (1) {
            return ngx_stream_access_found(s, rule_un[i].deny);
        }
    }

    return NGX_DECLINED;
}

#endif


static ngx_int_t
ngx_stream_access_found(ngx_stream_session_t *s, ngx_uint_t deny)
{
    if (deny) {
        ngx_log_error(NGX_LOG_ERR, s->connection->log, 0,
                      "access forbidden by rule");
        return NGX_STREAM_FORBIDDEN;
    }

    return NGX_OK;
}


static char *
ngx_stream_access_rule(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_stream_access_srv_conf_t *ascf = conf;

    ngx_int_t                     rc;
    ngx_uint_t                    all;
    ngx_str_t                    *value;
    ngx_cidr_t                    cidr;
    ngx_stream_access_rule_t     *rule;
#if (NGX_HAVE_INET6)
    ngx_stream_access_rule6_t    *rule6;
#endif
#if (NGX_HAVE_UNIX_DOMAIN)
    ngx_stream_access_rule_un_t  *rule_un;
#endif

    all = 0;
    ngx_memzero(&cidr, sizeof(ngx_cidr_t));

    value = cf->args->elts;

    if (value[1].len == 3 && ngx_strcmp(value[1].data, "all") == 0) {
        all = 1;

#if (NGX_HAVE_UNIX_DOMAIN)
    } else if (value[1].len == 5 && ngx_strcmp(value[1].data, "unix:") == 0) {
        cidr.family = AF_UNIX;
#endif

    } else {
        rc = ngx_ptocidr(&value[1], &cidr);

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

        if (rc == NGX_DONE) {
            ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
                         "low address bits of %V are meaningless", &value[1]);
        }
    }

    if (cidr.family == AF_INET || all) {

        if (ascf->rules == NULL) {
            ascf->rules = ngx_array_create(cf->pool, 4,
                                           sizeof(ngx_stream_access_rule_t));
            if (ascf->rules == NULL) {
                return NGX_CONF_ERROR;
            }
        }

        rule = ngx_array_push(ascf->rules);
        if (rule == NULL) {
            return NGX_CONF_ERROR;
        }

        rule->mask = cidr.u.in.mask;
        rule->addr = cidr.u.in.addr;
        rule->deny = (value[0].data[0] == 'd') ? 1 : 0;
    }

#if (NGX_HAVE_INET6)
    if (cidr.family == AF_INET6 || all) {

        if (ascf->rules6 == NULL) {
            ascf->rules6 = ngx_array_create(cf->pool, 4,
                                            sizeof(ngx_stream_access_rule6_t));
            if (ascf->rules6 == NULL) {
                return NGX_CONF_ERROR;
            }
        }

        rule6 = ngx_array_push(ascf->rules6);
        if (rule6 == NULL) {
            return NGX_CONF_ERROR;
        }

        rule6->mask = cidr.u.in6.mask;
        rule6->addr = cidr.u.in6.addr;
        rule6->deny = (value[0].data[0] == 'd') ? 1 : 0;
    }
#endif

#if (NGX_HAVE_UNIX_DOMAIN)
    if (cidr.family == AF_UNIX || all) {

        if (ascf->rules_un == NULL) {
            ascf->rules_un = ngx_array_create(cf->pool, 1,
                                          sizeof(ngx_stream_access_rule_un_t));
            if (ascf->rules_un == NULL) {
                return NGX_CONF_ERROR;
            }
        }

        rule_un = ngx_array_push(ascf->rules_un);
        if (rule_un == NULL) {
            return NGX_CONF_ERROR;
        }

        rule_un->deny = (value[0].data[0] == 'd') ? 1 : 0;
    }
#endif

    return NGX_CONF_OK;
}


static void *
ngx_stream_access_create_srv_conf(ngx_conf_t *cf)
{
    ngx_stream_access_srv_conf_t  *conf;

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

    return conf;
}


static char *
ngx_stream_access_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
{
    ngx_stream_access_srv_conf_t  *prev = parent;
    ngx_stream_access_srv_conf_t  *conf = child;

    if (conf->rules == NULL
#if (NGX_HAVE_INET6)
        && conf->rules6 == NULL
#endif
#if (NGX_HAVE_UNIX_DOMAIN)
        && conf->rules_un == NULL
#endif
    ) {
        conf->rules = prev->rules;
#if (NGX_HAVE_INET6)
        conf->rules6 = prev->rules6;
#endif
#if (NGX_HAVE_UNIX_DOMAIN)
        conf->rules_un = prev->rules_un;
#endif
    }

    return NGX_CONF_OK;
}


static ngx_int_t
ngx_stream_access_init(ngx_conf_t *cf)
{
    ngx_stream_handler_pt        *h;
    ngx_stream_core_main_conf_t  *cmcf;

    cmcf = ngx_stream_conf_get_module_main_conf(cf, ngx_stream_core_module);

    h = ngx_array_push(&cmcf->phases[NGX_STREAM_ACCESS_PHASE].handlers);
    if (h == NULL) {
        return NGX_ERROR;
    }

    *h = ngx_stream_access_handler;

    return NGX_OK;
}