Mercurial > hg > nginx
view src/mail/ngx_mail_imap_handler.c @ 7710:097f578a4a8f
HTTP/2: fixed segfault on DATA frames after 400 errors.
If 400 errors were redirected to an upstream server using the error_page
directive, DATA frames from the client might cause segmentation fault
due to null pointer dereference. The bug had appeared in 6989:2c4dbcd6f2e4
(1.13.0).
Fix is to skip such frames in ngx_http_v2_state_read_data() (similarly
to 7561:9f1f9d6e056a). With the fix, behaviour of 400 errors in HTTP/2
is now similar to one in HTTP/1.x, that is, nginx doesn't try to read the
request body.
Note that proxying 400 errors, as well as other early stage errors, to
upstream servers might not be a good idea anyway. These errors imply
that reading and processing of the request (and the request headers)
wasn't complete, and proxying of such incomplete request might lead to
various errors.
Reported by Chenglong Zhang.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 23 Sep 2020 19:50:49 +0300 |
parents | b2915d99ee8d |
children | ab6257dac2a8 |
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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_imap_module.h> static ngx_int_t ngx_mail_imap_login(ngx_mail_session_t *s, ngx_connection_t *c); static ngx_int_t ngx_mail_imap_authenticate(ngx_mail_session_t *s, ngx_connection_t *c); static ngx_int_t ngx_mail_imap_capability(ngx_mail_session_t *s, ngx_connection_t *c); static ngx_int_t ngx_mail_imap_starttls(ngx_mail_session_t *s, ngx_connection_t *c); static u_char imap_greeting[] = "* OK IMAP4 ready" CRLF; static u_char imap_star[] = "* "; static u_char imap_ok[] = "OK completed" CRLF; static u_char imap_next[] = "+ OK" CRLF; static u_char imap_plain_next[] = "+ " CRLF; static u_char imap_username[] = "+ VXNlcm5hbWU6" CRLF; static u_char imap_password[] = "+ UGFzc3dvcmQ6" CRLF; static u_char imap_bye[] = "* BYE" CRLF; static u_char imap_invalid_command[] = "BAD invalid command" CRLF; void ngx_mail_imap_init_session(ngx_mail_session_t *s, ngx_connection_t *c) { ngx_mail_core_srv_conf_t *cscf; cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module); ngx_str_set(&s->out, imap_greeting); c->read->handler = ngx_mail_imap_init_protocol; ngx_add_timer(c->read, cscf->timeout); if (ngx_handle_read_event(c->read, 0) != NGX_OK) { ngx_mail_close_connection(c); } ngx_mail_send(c->write); } void ngx_mail_imap_init_protocol(ngx_event_t *rev) { ngx_connection_t *c; ngx_mail_session_t *s; ngx_mail_imap_srv_conf_t *iscf; c = rev->data; c->log->action = "in auth state"; if (rev->timedout) { ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out"); c->timedout = 1; ngx_mail_close_connection(c); return; } s = c->data; if (s->buffer == NULL) { if (ngx_array_init(&s->args, c->pool, 2, sizeof(ngx_str_t)) == NGX_ERROR) { ngx_mail_session_internal_server_error(s); return; } iscf = ngx_mail_get_module_srv_conf(s, ngx_mail_imap_module); s->buffer = ngx_create_temp_buf(c->pool, iscf->client_buffer_size); if (s->buffer == NULL) { ngx_mail_session_internal_server_error(s); return; } } s->mail_state = ngx_imap_start; c->read->handler = ngx_mail_imap_auth_state; ngx_mail_imap_auth_state(rev); } void ngx_mail_imap_auth_state(ngx_event_t *rev) { u_char *p, *dst, *src, *end; ngx_str_t *arg; ngx_int_t rc; ngx_uint_t tag, i; ngx_connection_t *c; ngx_mail_session_t *s; c = rev->data; s = c->data; ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "imap auth state"); if (rev->timedout) { ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out"); c->timedout = 1; ngx_mail_close_connection(c); return; } if (s->out.len) { ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "imap send handler busy"); s->blocked = 1; return; } s->blocked = 0; rc = ngx_mail_read_command(s, c); if (rc == NGX_AGAIN || rc == NGX_ERROR) { return; } tag = 1; s->text.len = 0; ngx_str_set(&s->out, imap_ok); if (rc == NGX_OK) { ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0, "imap auth command: %i", s->command); if (s->backslash) { arg = s->args.elts; for (i = 0; i < s->args.nelts; i++) { dst = arg[i].data; end = dst + arg[i].len; for (src = dst; src < end; dst++) { *dst = *src; if (*src++ == '\\') { *dst = *src++; } } arg[i].len = dst - arg[i].data; } s->backslash = 0; } switch (s->mail_state) { case ngx_imap_start: switch (s->command) { case NGX_IMAP_LOGIN: rc = ngx_mail_imap_login(s, c); break; case NGX_IMAP_AUTHENTICATE: rc = ngx_mail_imap_authenticate(s, c); tag = (rc != NGX_OK); break; case NGX_IMAP_CAPABILITY: rc = ngx_mail_imap_capability(s, c); break; case NGX_IMAP_LOGOUT: s->quit = 1; ngx_str_set(&s->text, imap_bye); break; case NGX_IMAP_NOOP: break; case NGX_IMAP_STARTTLS: rc = ngx_mail_imap_starttls(s, c); break; default: rc = NGX_MAIL_PARSE_INVALID_COMMAND; break; } break; case ngx_imap_auth_login_username: rc = ngx_mail_auth_login_username(s, c, 0); tag = 0; ngx_str_set(&s->out, imap_password); s->mail_state = ngx_imap_auth_login_password; break; case ngx_imap_auth_login_password: rc = ngx_mail_auth_login_password(s, c); break; case ngx_imap_auth_plain: rc = ngx_mail_auth_plain(s, c, 0); break; case ngx_imap_auth_cram_md5: rc = ngx_mail_auth_cram_md5(s, c); break; case ngx_imap_auth_external: rc = ngx_mail_auth_external(s, c, 0); break; } } else if (rc == NGX_IMAP_NEXT) { tag = 0; ngx_str_set(&s->out, imap_next); } switch (rc) { case NGX_DONE: ngx_mail_auth(s, c); return; case NGX_ERROR: ngx_mail_session_internal_server_error(s); return; case NGX_MAIL_PARSE_INVALID_COMMAND: s->state = 0; ngx_str_set(&s->out, imap_invalid_command); s->mail_state = ngx_imap_start; break; } if (tag) { if (s->tag.len == 0) { ngx_str_set(&s->tag, imap_star); } if (s->tagged_line.len < s->tag.len + s->text.len + s->out.len) { s->tagged_line.len = s->tag.len + s->text.len + s->out.len; s->tagged_line.data = ngx_pnalloc(c->pool, s->tagged_line.len); if (s->tagged_line.data == NULL) { ngx_mail_close_connection(c); return; } } p = s->tagged_line.data; if (s->text.len) { p = ngx_cpymem(p, s->text.data, s->text.len); } p = ngx_cpymem(p, s->tag.data, s->tag.len); ngx_memcpy(p, s->out.data, s->out.len); s->out.len = s->text.len + s->tag.len + s->out.len; s->out.data = s->tagged_line.data; } if (rc != NGX_IMAP_NEXT) { s->args.nelts = 0; if (s->state) { /* preserve tag */ s->arg_start = s->buffer->start + s->tag.len; s->buffer->pos = s->arg_start; s->buffer->last = s->arg_start; } else { s->buffer->pos = s->buffer->start; s->buffer->last = s->buffer->start; s->tag.len = 0; } } ngx_mail_send(c->write); } static ngx_int_t ngx_mail_imap_login(ngx_mail_session_t *s, ngx_connection_t *c) { ngx_str_t *arg; #if (NGX_MAIL_SSL) if (ngx_mail_starttls_only(s, c)) { return NGX_MAIL_PARSE_INVALID_COMMAND; } #endif arg = s->args.elts; if (s->args.nelts != 2 || arg[0].len == 0) { return NGX_MAIL_PARSE_INVALID_COMMAND; } s->login.len = arg[0].len; s->login.data = ngx_pnalloc(c->pool, s->login.len); if (s->login.data == NULL) { return NGX_ERROR; } ngx_memcpy(s->login.data, arg[0].data, s->login.len); s->passwd.len = arg[1].len; s->passwd.data = ngx_pnalloc(c->pool, s->passwd.len); if (s->passwd.data == NULL) { return NGX_ERROR; } ngx_memcpy(s->passwd.data, arg[1].data, s->passwd.len); #if (NGX_DEBUG_MAIL_PASSWD) ngx_log_debug2(NGX_LOG_DEBUG_MAIL, c->log, 0, "imap login:\"%V\" passwd:\"%V\"", &s->login, &s->passwd); #else ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0, "imap login:\"%V\"", &s->login); #endif return NGX_DONE; } static ngx_int_t ngx_mail_imap_authenticate(ngx_mail_session_t *s, ngx_connection_t *c) { ngx_int_t rc; ngx_mail_core_srv_conf_t *cscf; ngx_mail_imap_srv_conf_t *iscf; #if (NGX_MAIL_SSL) if (ngx_mail_starttls_only(s, c)) { return NGX_MAIL_PARSE_INVALID_COMMAND; } #endif iscf = ngx_mail_get_module_srv_conf(s, ngx_mail_imap_module); rc = ngx_mail_auth_parse(s, c); switch (rc) { case NGX_MAIL_AUTH_LOGIN: ngx_str_set(&s->out, imap_username); s->mail_state = ngx_imap_auth_login_username; return NGX_OK; case NGX_MAIL_AUTH_LOGIN_USERNAME: ngx_str_set(&s->out, imap_password); s->mail_state = ngx_imap_auth_login_password; return ngx_mail_auth_login_username(s, c, 1); case NGX_MAIL_AUTH_PLAIN: ngx_str_set(&s->out, imap_plain_next); s->mail_state = ngx_imap_auth_plain; return NGX_OK; case NGX_MAIL_AUTH_CRAM_MD5: if (!(iscf->auth_methods & NGX_MAIL_AUTH_CRAM_MD5_ENABLED)) { return NGX_MAIL_PARSE_INVALID_COMMAND; } if (s->salt.data == NULL) { cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module); if (ngx_mail_salt(s, c, cscf) != NGX_OK) { return NGX_ERROR; } } if (ngx_mail_auth_cram_md5_salt(s, c, "+ ", 2) == NGX_OK) { s->mail_state = ngx_imap_auth_cram_md5; return NGX_OK; } return NGX_ERROR; case NGX_MAIL_AUTH_EXTERNAL: if (!(iscf->auth_methods & NGX_MAIL_AUTH_EXTERNAL_ENABLED)) { return NGX_MAIL_PARSE_INVALID_COMMAND; } ngx_str_set(&s->out, imap_username); s->mail_state = ngx_imap_auth_external; return NGX_OK; } return rc; } static ngx_int_t ngx_mail_imap_capability(ngx_mail_session_t *s, ngx_connection_t *c) { ngx_mail_imap_srv_conf_t *iscf; iscf = ngx_mail_get_module_srv_conf(s, ngx_mail_imap_module); #if (NGX_MAIL_SSL) if (c->ssl == NULL) { ngx_mail_ssl_conf_t *sslcf; sslcf = ngx_mail_get_module_srv_conf(s, ngx_mail_ssl_module); if (sslcf->starttls == NGX_MAIL_STARTTLS_ON) { s->text = iscf->starttls_capability; return NGX_OK; } if (sslcf->starttls == NGX_MAIL_STARTTLS_ONLY) { s->text = iscf->starttls_only_capability; return NGX_OK; } } #endif s->text = iscf->capability; return NGX_OK; } static ngx_int_t ngx_mail_imap_starttls(ngx_mail_session_t *s, ngx_connection_t *c) { #if (NGX_MAIL_SSL) ngx_mail_ssl_conf_t *sslcf; if (c->ssl == NULL) { sslcf = ngx_mail_get_module_srv_conf(s, ngx_mail_ssl_module); if (sslcf->starttls) { c->read->handler = ngx_mail_starttls_handler; return NGX_OK; } } #endif return NGX_MAIL_PARSE_INVALID_COMMAND; }