Mercurial > hg > nginx
view src/mail/ngx_mail_pop3_module.c @ 8913:40445fc7c403 quic
QUIC: fixed migration during NAT rebinding.
The RFC 9000 allows a packet from known CID arrive from unknown path:
These requirements regarding connection ID reuse apply only to the
sending of packets, as unintentional changes in path without a change
in connection ID are possible. For example, after a period of
network inactivity, NAT rebinding might cause packets to be sent on a
new path when the client resumes sending.
Before the patch, such packets were rejected with an error in the
ngx_quic_check_migration() function. Removing the check makes the
separate function excessive - remaining checks are early migration
check and "disable_active_migration" check. The latter is a transport
parameter sent to client and it should not be used by server.
The server should send "disable_active_migration" "if the endpoint does
not support active connection migration" (18.2). The support status depends
on nginx configuration: to have migration working with multiple workers,
you need bpf helper, available on recent Linux systems. The patch does
not set "disable_active_migration" automatically and leaves it for the
administrator. By default, active migration is enabled.
RFC 900 says that it is ok to migrate if the peer violates
"disable_active_migration" flag requirements:
If the peer violates this requirement,
the endpoint MUST either drop the incoming packets on that path without
generating a Stateless Reset
OR
proceed with path validation and allow the peer to migrate. Generating a
Stateless Reset or closing the connection would allow third parties in the
network to cause connections to close by spoofing or otherwise manipulating
observed traffic.
So, nginx adheres to the second option and proceeds to path validation.
Note:
The ngtcp2 may be used for testing both active migration and NAT rebinding:
ngtcp2/client --change-local-addr=200ms --delay-stream=500ms <ip> <port> <url>
ngtcp2/client --change-local-addr=200ms --delay-stream=500ms --nat-rebinding \
<ip> <port> <url>
author | Vladimir Homutov <vl@nginx.com> |
---|---|
date | Mon, 29 Nov 2021 11:51:14 +0300 |
parents | dc955d274130 |
children | 4538c1ffb0f8 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> #include <ngx_mail.h> #include <ngx_mail_pop3_module.h> static void *ngx_mail_pop3_create_srv_conf(ngx_conf_t *cf); static char *ngx_mail_pop3_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child); static ngx_str_t ngx_mail_pop3_default_capabilities[] = { ngx_string("TOP"), ngx_string("USER"), ngx_string("UIDL"), ngx_null_string }; static ngx_conf_bitmask_t ngx_mail_pop3_auth_methods[] = { { ngx_string("plain"), NGX_MAIL_AUTH_PLAIN_ENABLED }, { ngx_string("apop"), NGX_MAIL_AUTH_APOP_ENABLED }, { ngx_string("cram-md5"), NGX_MAIL_AUTH_CRAM_MD5_ENABLED }, { ngx_string("external"), NGX_MAIL_AUTH_EXTERNAL_ENABLED }, { ngx_null_string, 0 } }; static ngx_str_t ngx_mail_pop3_auth_methods_names[] = { ngx_string("PLAIN"), ngx_string("LOGIN"), ngx_null_string, /* APOP */ ngx_string("CRAM-MD5"), ngx_string("EXTERNAL"), ngx_null_string /* NONE */ }; static ngx_mail_protocol_t ngx_mail_pop3_protocol = { ngx_string("pop3"), ngx_string("\x04pop3"), { 110, 995, 0, 0 }, NGX_MAIL_POP3_PROTOCOL, ngx_mail_pop3_init_session, ngx_mail_pop3_init_protocol, ngx_mail_pop3_parse_command, ngx_mail_pop3_auth_state, ngx_string("-ERR internal server error" CRLF), ngx_string("-ERR SSL certificate error" CRLF), ngx_string("-ERR No required SSL certificate" CRLF) }; static ngx_command_t ngx_mail_pop3_commands[] = { { ngx_string("pop3_capabilities"), NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_1MORE, ngx_mail_capabilities, NGX_MAIL_SRV_CONF_OFFSET, offsetof(ngx_mail_pop3_srv_conf_t, capabilities), NULL }, { ngx_string("pop3_auth"), NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_1MORE, ngx_conf_set_bitmask_slot, NGX_MAIL_SRV_CONF_OFFSET, offsetof(ngx_mail_pop3_srv_conf_t, auth_methods), &ngx_mail_pop3_auth_methods }, ngx_null_command }; static ngx_mail_module_t ngx_mail_pop3_module_ctx = { &ngx_mail_pop3_protocol, /* protocol */ NULL, /* create main configuration */ NULL, /* init main configuration */ ngx_mail_pop3_create_srv_conf, /* create server configuration */ ngx_mail_pop3_merge_srv_conf /* merge server configuration */ }; ngx_module_t ngx_mail_pop3_module = { NGX_MODULE_V1, &ngx_mail_pop3_module_ctx, /* module context */ ngx_mail_pop3_commands, /* module directives */ NGX_MAIL_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 void * ngx_mail_pop3_create_srv_conf(ngx_conf_t *cf) { ngx_mail_pop3_srv_conf_t *pscf; pscf = ngx_pcalloc(cf->pool, sizeof(ngx_mail_pop3_srv_conf_t)); if (pscf == NULL) { return NULL; } if (ngx_array_init(&pscf->capabilities, cf->pool, 4, sizeof(ngx_str_t)) != NGX_OK) { return NULL; } return pscf; } static char * ngx_mail_pop3_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_mail_pop3_srv_conf_t *prev = parent; ngx_mail_pop3_srv_conf_t *conf = child; u_char *p; size_t size, stls_only_size; ngx_str_t *c, *d; ngx_uint_t i, m; ngx_conf_merge_bitmask_value(conf->auth_methods, prev->auth_methods, (NGX_CONF_BITMASK_SET |NGX_MAIL_AUTH_PLAIN_ENABLED)); if (conf->auth_methods & NGX_MAIL_AUTH_PLAIN_ENABLED) { conf->auth_methods |= NGX_MAIL_AUTH_LOGIN_ENABLED; } if (conf->capabilities.nelts == 0) { conf->capabilities = prev->capabilities; } if (conf->capabilities.nelts == 0) { for (d = ngx_mail_pop3_default_capabilities; d->len; d++) { c = ngx_array_push(&conf->capabilities); if (c == NULL) { return NGX_CONF_ERROR; } *c = *d; } } size = sizeof("+OK Capability list follows" CRLF) - 1 + sizeof("." CRLF) - 1; stls_only_size = size + sizeof("STLS" CRLF) - 1; c = conf->capabilities.elts; for (i = 0; i < conf->capabilities.nelts; i++) { size += c[i].len + sizeof(CRLF) - 1; if (ngx_strcasecmp(c[i].data, (u_char *) "USER") == 0) { continue; } stls_only_size += c[i].len + sizeof(CRLF) - 1; } size += sizeof("SASL") - 1 + sizeof(CRLF) - 1; for (m = NGX_MAIL_AUTH_PLAIN_ENABLED, i = 0; m <= NGX_MAIL_AUTH_EXTERNAL_ENABLED; m <<= 1, i++) { if (ngx_mail_pop3_auth_methods_names[i].len == 0) { continue; } if (m & conf->auth_methods) { size += 1 + ngx_mail_pop3_auth_methods_names[i].len; } } p = ngx_pnalloc(cf->pool, size); if (p == NULL) { return NGX_CONF_ERROR; } conf->capability.len = size; conf->capability.data = p; p = ngx_cpymem(p, "+OK Capability list follows" CRLF, sizeof("+OK Capability list follows" CRLF) - 1); for (i = 0; i < conf->capabilities.nelts; i++) { p = ngx_cpymem(p, c[i].data, c[i].len); *p++ = CR; *p++ = LF; } p = ngx_cpymem(p, "SASL", sizeof("SASL") - 1); for (m = NGX_MAIL_AUTH_PLAIN_ENABLED, i = 0; m <= NGX_MAIL_AUTH_EXTERNAL_ENABLED; m <<= 1, i++) { if (ngx_mail_pop3_auth_methods_names[i].len == 0) { continue; } if (m & conf->auth_methods) { *p++ = ' '; p = ngx_cpymem(p, ngx_mail_pop3_auth_methods_names[i].data, ngx_mail_pop3_auth_methods_names[i].len); } } *p++ = CR; *p++ = LF; *p++ = '.'; *p++ = CR; *p = LF; size += sizeof("STLS" CRLF) - 1; p = ngx_pnalloc(cf->pool, size); if (p == NULL) { return NGX_CONF_ERROR; } conf->starttls_capability.len = size; conf->starttls_capability.data = p; p = ngx_cpymem(p, conf->capability.data, conf->capability.len - (sizeof("." CRLF) - 1)); p = ngx_cpymem(p, "STLS" CRLF, sizeof("STLS" CRLF) - 1); *p++ = '.'; *p++ = CR; *p = LF; size = sizeof("+OK methods supported:" CRLF) - 1 + sizeof("." CRLF) - 1; for (m = NGX_MAIL_AUTH_PLAIN_ENABLED, i = 0; m <= NGX_MAIL_AUTH_EXTERNAL_ENABLED; m <<= 1, i++) { if (ngx_mail_pop3_auth_methods_names[i].len == 0) { continue; } if (m & conf->auth_methods) { size += ngx_mail_pop3_auth_methods_names[i].len + sizeof(CRLF) - 1; } } p = ngx_pnalloc(cf->pool, size); if (p == NULL) { return NGX_CONF_ERROR; } conf->auth_capability.data = p; conf->auth_capability.len = size; p = ngx_cpymem(p, "+OK methods supported:" CRLF, sizeof("+OK methods supported:" CRLF) - 1); for (m = NGX_MAIL_AUTH_PLAIN_ENABLED, i = 0; m <= NGX_MAIL_AUTH_EXTERNAL_ENABLED; m <<= 1, i++) { if (ngx_mail_pop3_auth_methods_names[i].len == 0) { continue; } if (m & conf->auth_methods) { p = ngx_cpymem(p, ngx_mail_pop3_auth_methods_names[i].data, ngx_mail_pop3_auth_methods_names[i].len); *p++ = CR; *p++ = LF; } } *p++ = '.'; *p++ = CR; *p = LF; p = ngx_pnalloc(cf->pool, stls_only_size); if (p == NULL) { return NGX_CONF_ERROR; } conf->starttls_only_capability.len = stls_only_size; conf->starttls_only_capability.data = p; p = ngx_cpymem(p, "+OK Capability list follows" CRLF, sizeof("+OK Capability list follows" CRLF) - 1); for (i = 0; i < conf->capabilities.nelts; i++) { if (ngx_strcasecmp(c[i].data, (u_char *) "USER") == 0) { continue; } p = ngx_cpymem(p, c[i].data, c[i].len); *p++ = CR; *p++ = LF; } p = ngx_cpymem(p, "STLS" CRLF, sizeof("STLS" CRLF) - 1); *p++ = '.'; *p++ = CR; *p = LF; return NGX_CONF_OK; }