Mercurial > hg > nginx-quic
view src/mail/ngx_mail_imap_module.h @ 6359:dac6eda40475 stable-1.8
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 | d620f497c50f |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_MAIL_IMAP_MODULE_H_INCLUDED_ #define _NGX_MAIL_IMAP_MODULE_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_mail.h> typedef struct { size_t client_buffer_size; ngx_str_t capability; ngx_str_t starttls_capability; ngx_str_t starttls_only_capability; ngx_uint_t auth_methods; ngx_array_t capabilities; } ngx_mail_imap_srv_conf_t; void ngx_mail_imap_init_session(ngx_mail_session_t *s, ngx_connection_t *c); void ngx_mail_imap_init_protocol(ngx_event_t *rev); void ngx_mail_imap_auth_state(ngx_event_t *rev); ngx_int_t ngx_mail_imap_parse_command(ngx_mail_session_t *s); extern ngx_module_t ngx_mail_imap_module; #endif /* _NGX_MAIL_IMAP_MODULE_H_INCLUDED_ */