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view src/core/ngx_inet.h @ 6351:497d0cff8ace

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Resolver: fixed use-after-free memory accesses with CNAME. When several requests were waiting for a response, then after getting a CNAME response only the last request's context had the name updated. Contexts of other requests had the wrong name. This name was used by ngx_resolve_name_done() to find the node to remove the request context from. When the name was wrong, the request could not be properly cancelled, its context was freed but stayed linked to the node's waiting list. This happened e.g. when the first request was aborted or timed out before the resolving completed. When it completed, this triggered a use-after-free memory access by calling ctx->handler of already freed request context. The bug manifests itself by "could not cancel <name> resolving" alerts in error_log. When a request was responded with a CNAME, the request context kept the pointer to the original node's rn->u.cname. If the original node expired before the resolving timed out or completed with an error, this would trigger a use-after-free memory access via ctx->name in ctx->handler(). The fix is to keep ctx->name unmodified. The name from context is no longer used by ngx_resolve_name_done(). Instead, we now keep the pointer to resolver node to which this request is linked. Keeping the original name intact also improves logging.
author Roman Arutyunyan <arut@nginx.com>
date Tue, 26 Jan 2016 16:46:59 +0300
parents d39ef821d03e
children 6d3a60a909c8
line wrap: on
line source


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


#ifndef _NGX_INET_H_INCLUDED_
#define _NGX_INET_H_INCLUDED_


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


/*
 * TODO: autoconfigure NGX_SOCKADDRLEN and NGX_SOCKADDR_STRLEN as
 *       sizeof(struct sockaddr_storage)
 *       sizeof(struct sockaddr_un)
 *       sizeof(struct sockaddr_in6)
 *       sizeof(struct sockaddr_in)
 */

#define NGX_INET_ADDRSTRLEN   (sizeof("255.255.255.255") - 1)
#define NGX_INET6_ADDRSTRLEN                                                 \
    (sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255") - 1)
#define NGX_UNIX_ADDRSTRLEN                                                  \
    (sizeof(struct sockaddr_un) - offsetof(struct sockaddr_un, sun_path))

#if (NGX_HAVE_UNIX_DOMAIN)
#define NGX_SOCKADDR_STRLEN   (sizeof("unix:") - 1 + NGX_UNIX_ADDRSTRLEN)
#else
#define NGX_SOCKADDR_STRLEN   (NGX_INET6_ADDRSTRLEN + sizeof("[]:65535") - 1)
#endif

#if (NGX_HAVE_UNIX_DOMAIN)
#define NGX_SOCKADDRLEN       sizeof(struct sockaddr_un)
#else
#define NGX_SOCKADDRLEN       512
#endif


typedef struct {
    in_addr_t                 addr;
    in_addr_t                 mask;
} ngx_in_cidr_t;


#if (NGX_HAVE_INET6)

typedef struct {
    struct in6_addr           addr;
    struct in6_addr           mask;
} ngx_in6_cidr_t;

#endif


typedef struct {
    ngx_uint_t                family;
    union {
        ngx_in_cidr_t         in;
#if (NGX_HAVE_INET6)
        ngx_in6_cidr_t        in6;
#endif
    } u;
} ngx_cidr_t;


typedef struct {
    struct sockaddr          *sockaddr;
    socklen_t                 socklen;
    ngx_str_t                 name;
} ngx_addr_t;


typedef struct {
    ngx_str_t                 url;
    ngx_str_t                 host;
    ngx_str_t                 port_text;
    ngx_str_t                 uri;

    in_port_t                 port;
    in_port_t                 default_port;
    int                       family;

    unsigned                  listen:1;
    unsigned                  uri_part:1;
    unsigned                  no_resolve:1;
    unsigned                  one_addr:1;  /* compatibility */

    unsigned                  no_port:1;
    unsigned                  wildcard:1;

    socklen_t                 socklen;
    u_char                    sockaddr[NGX_SOCKADDRLEN];

    ngx_addr_t               *addrs;
    ngx_uint_t                naddrs;

    char                     *err;
} ngx_url_t;


in_addr_t ngx_inet_addr(u_char *text, size_t len);
#if (NGX_HAVE_INET6)
ngx_int_t ngx_inet6_addr(u_char *p, size_t len, u_char *addr);
size_t ngx_inet6_ntop(u_char *p, u_char *text, size_t len);
#endif
size_t ngx_sock_ntop(struct sockaddr *sa, socklen_t socklen, u_char *text,
    size_t len, ngx_uint_t port);
size_t ngx_inet_ntop(int family, void *addr, u_char *text, size_t len);
ngx_int_t ngx_ptocidr(ngx_str_t *text, ngx_cidr_t *cidr);
ngx_int_t ngx_parse_addr(ngx_pool_t *pool, ngx_addr_t *addr, u_char *text,
    size_t len);
ngx_int_t ngx_parse_url(ngx_pool_t *pool, ngx_url_t *u);
ngx_int_t ngx_inet_resolve_host(ngx_pool_t *pool, ngx_url_t *u);
ngx_int_t ngx_cmp_sockaddr(struct sockaddr *sa1, socklen_t slen1,
    struct sockaddr *sa2, socklen_t slen2, ngx_uint_t cmp_port);


#endif /* _NGX_INET_H_INCLUDED_ */