Mercurial > hg > nginx
view src/core/ngx_core.h @ 6351:497d0cff8ace
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 | 8b6fa4842133 |
| children | 0f203a2af17c |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_CORE_H_INCLUDED_ #define _NGX_CORE_H_INCLUDED_ #include <ngx_config.h> typedef struct ngx_module_s ngx_module_t; typedef struct ngx_conf_s ngx_conf_t; typedef struct ngx_cycle_s ngx_cycle_t; typedef struct ngx_pool_s ngx_pool_t; typedef struct ngx_chain_s ngx_chain_t; typedef struct ngx_log_s ngx_log_t; typedef struct ngx_open_file_s ngx_open_file_t; typedef struct ngx_command_s ngx_command_t; typedef struct ngx_file_s ngx_file_t; typedef struct ngx_event_s ngx_event_t; typedef struct ngx_event_aio_s ngx_event_aio_t; typedef struct ngx_connection_s ngx_connection_t; #if (NGX_THREADS) typedef struct ngx_thread_task_s ngx_thread_task_t; #endif typedef void (*ngx_event_handler_pt)(ngx_event_t *ev); typedef void (*ngx_connection_handler_pt)(ngx_connection_t *c); #define NGX_OK 0 #define NGX_ERROR -1 #define NGX_AGAIN -2 #define NGX_BUSY -3 #define NGX_DONE -4 #define NGX_DECLINED -5 #define NGX_ABORT -6 #include <ngx_errno.h> #include <ngx_atomic.h> #include <ngx_thread.h> #include <ngx_rbtree.h> #include <ngx_time.h> #include <ngx_socket.h> #include <ngx_string.h> #include <ngx_files.h> #include <ngx_shmem.h> #include <ngx_process.h> #include <ngx_user.h> #include <ngx_parse.h> #include <ngx_parse_time.h> #include <ngx_log.h> #include <ngx_alloc.h> #include <ngx_palloc.h> #include <ngx_buf.h> #include <ngx_queue.h> #include <ngx_array.h> #include <ngx_list.h> #include <ngx_hash.h> #include <ngx_file.h> #include <ngx_crc.h> #include <ngx_crc32.h> #include <ngx_murmurhash.h> #if (NGX_PCRE) #include <ngx_regex.h> #endif #include <ngx_radix_tree.h> #include <ngx_times.h> #include <ngx_rwlock.h> #include <ngx_shmtx.h> #include <ngx_slab.h> #include <ngx_inet.h> #include <ngx_cycle.h> #include <ngx_resolver.h> #if (NGX_OPENSSL) #include <ngx_event_openssl.h> #endif #include <ngx_process_cycle.h> #include <ngx_conf_file.h> #include <ngx_open_file_cache.h> #include <ngx_os.h> #include <ngx_connection.h> #include <ngx_syslog.h> #include <ngx_proxy_protocol.h> #define LF (u_char) '\n' #define CR (u_char) '\r' #define CRLF "\r\n" #define ngx_abs(value) (((value) >= 0) ? (value) : - (value)) #define ngx_max(val1, val2) ((val1 < val2) ? (val2) : (val1)) #define ngx_min(val1, val2) ((val1 > val2) ? (val2) : (val1)) void ngx_cpuinfo(void); #if (NGX_HAVE_OPENAT) #define NGX_DISABLE_SYMLINKS_OFF 0 #define NGX_DISABLE_SYMLINKS_ON 1 #define NGX_DISABLE_SYMLINKS_NOTOWNER 2 #endif #endif /* _NGX_CORE_H_INCLUDED_ */