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view src/core/ngx_conf_file.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 18428f775b2c
children 0f203a2af17c
line wrap: on
line source


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


#ifndef _NGX_CONF_FILE_H_INCLUDED_
#define _NGX_CONF_FILE_H_INCLUDED_


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


/*
 *        AAAA  number of arguments
 *      FF      command flags
 *    TT        command type, i.e. HTTP "location" or "server" command
 */

#define NGX_CONF_NOARGS      0x00000001
#define NGX_CONF_TAKE1       0x00000002
#define NGX_CONF_TAKE2       0x00000004
#define NGX_CONF_TAKE3       0x00000008
#define NGX_CONF_TAKE4       0x00000010
#define NGX_CONF_TAKE5       0x00000020
#define NGX_CONF_TAKE6       0x00000040
#define NGX_CONF_TAKE7       0x00000080

#define NGX_CONF_MAX_ARGS    8

#define NGX_CONF_TAKE12      (NGX_CONF_TAKE1|NGX_CONF_TAKE2)
#define NGX_CONF_TAKE13      (NGX_CONF_TAKE1|NGX_CONF_TAKE3)

#define NGX_CONF_TAKE23      (NGX_CONF_TAKE2|NGX_CONF_TAKE3)

#define NGX_CONF_TAKE123     (NGX_CONF_TAKE1|NGX_CONF_TAKE2|NGX_CONF_TAKE3)
#define NGX_CONF_TAKE1234    (NGX_CONF_TAKE1|NGX_CONF_TAKE2|NGX_CONF_TAKE3   \
                              |NGX_CONF_TAKE4)

#define NGX_CONF_ARGS_NUMBER 0x000000ff
#define NGX_CONF_BLOCK       0x00000100
#define NGX_CONF_FLAG        0x00000200
#define NGX_CONF_ANY         0x00000400
#define NGX_CONF_1MORE       0x00000800
#define NGX_CONF_2MORE       0x00001000
#define NGX_CONF_MULTI       0x00000000  /* compatibility */

#define NGX_DIRECT_CONF      0x00010000

#define NGX_MAIN_CONF        0x01000000
#define NGX_ANY_CONF         0x1F000000



#define NGX_CONF_UNSET       -1
#define NGX_CONF_UNSET_UINT  (ngx_uint_t) -1
#define NGX_CONF_UNSET_PTR   (void *) -1
#define NGX_CONF_UNSET_SIZE  (size_t) -1
#define NGX_CONF_UNSET_MSEC  (ngx_msec_t) -1


#define NGX_CONF_OK          NULL
#define NGX_CONF_ERROR       (void *) -1

#define NGX_CONF_BLOCK_START 1
#define NGX_CONF_BLOCK_DONE  2
#define NGX_CONF_FILE_DONE   3

#define NGX_CORE_MODULE      0x45524F43  /* "CORE" */
#define NGX_CONF_MODULE      0x464E4F43  /* "CONF" */


#define NGX_MAX_CONF_ERRSTR  1024


struct ngx_command_s {
    ngx_str_t             name;
    ngx_uint_t            type;
    char               *(*set)(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
    ngx_uint_t            conf;
    ngx_uint_t            offset;
    void                 *post;
};

#define ngx_null_command  { ngx_null_string, 0, NULL, 0, 0, NULL }


struct ngx_open_file_s {
    ngx_fd_t              fd;
    ngx_str_t             name;

    void                (*flush)(ngx_open_file_t *file, ngx_log_t *log);
    void                 *data;
};


#define NGX_MODULE_V1          0, 0, 0, 0, 0, 0, 1
#define NGX_MODULE_V1_PADDING  0, 0, 0, 0, 0, 0, 0, 0

struct ngx_module_s {
    ngx_uint_t            ctx_index;
    ngx_uint_t            index;

    ngx_uint_t            spare0;
    ngx_uint_t            spare1;
    ngx_uint_t            spare2;
    ngx_uint_t            spare3;

    ngx_uint_t            version;

    void                 *ctx;
    ngx_command_t        *commands;
    ngx_uint_t            type;

    ngx_int_t           (*init_master)(ngx_log_t *log);

    ngx_int_t           (*init_module)(ngx_cycle_t *cycle);

    ngx_int_t           (*init_process)(ngx_cycle_t *cycle);
    ngx_int_t           (*init_thread)(ngx_cycle_t *cycle);
    void                (*exit_thread)(ngx_cycle_t *cycle);
    void                (*exit_process)(ngx_cycle_t *cycle);

    void                (*exit_master)(ngx_cycle_t *cycle);

    uintptr_t             spare_hook0;
    uintptr_t             spare_hook1;
    uintptr_t             spare_hook2;
    uintptr_t             spare_hook3;
    uintptr_t             spare_hook4;
    uintptr_t             spare_hook5;
    uintptr_t             spare_hook6;
    uintptr_t             spare_hook7;
};


typedef struct {
    ngx_str_t             name;
    void               *(*create_conf)(ngx_cycle_t *cycle);
    char               *(*init_conf)(ngx_cycle_t *cycle, void *conf);
} ngx_core_module_t;


typedef struct {
    ngx_file_t            file;
    ngx_buf_t            *buffer;
    ngx_buf_t            *dump;
    ngx_uint_t            line;
} ngx_conf_file_t;


typedef struct {
    ngx_str_t             name;
    ngx_buf_t            *buffer;
} ngx_conf_dump_t;


typedef char *(*ngx_conf_handler_pt)(ngx_conf_t *cf,
    ngx_command_t *dummy, void *conf);


struct ngx_conf_s {
    char                 *name;
    ngx_array_t          *args;

    ngx_cycle_t          *cycle;
    ngx_pool_t           *pool;
    ngx_pool_t           *temp_pool;
    ngx_conf_file_t      *conf_file;
    ngx_log_t            *log;

    void                 *ctx;
    ngx_uint_t            module_type;
    ngx_uint_t            cmd_type;

    ngx_conf_handler_pt   handler;
    char                 *handler_conf;
};


typedef char *(*ngx_conf_post_handler_pt) (ngx_conf_t *cf,
    void *data, void *conf);

typedef struct {
    ngx_conf_post_handler_pt  post_handler;
} ngx_conf_post_t;


typedef struct {
    ngx_conf_post_handler_pt  post_handler;
    char                     *old_name;
    char                     *new_name;
} ngx_conf_deprecated_t;


typedef struct {
    ngx_conf_post_handler_pt  post_handler;
    ngx_int_t                 low;
    ngx_int_t                 high;
} ngx_conf_num_bounds_t;


typedef struct {
    ngx_str_t                 name;
    ngx_uint_t                value;
} ngx_conf_enum_t;


#define NGX_CONF_BITMASK_SET  1

typedef struct {
    ngx_str_t                 name;
    ngx_uint_t                mask;
} ngx_conf_bitmask_t;



char * ngx_conf_deprecated(ngx_conf_t *cf, void *post, void *data);
char *ngx_conf_check_num_bounds(ngx_conf_t *cf, void *post, void *data);


#define ngx_get_conf(conf_ctx, module)  conf_ctx[module.index]



#define ngx_conf_init_value(conf, default)                                   \
    if (conf == NGX_CONF_UNSET) {                                            \
        conf = default;                                                      \
    }

#define ngx_conf_init_ptr_value(conf, default)                               \
    if (conf == NGX_CONF_UNSET_PTR) {                                        \
        conf = default;                                                      \
    }

#define ngx_conf_init_uint_value(conf, default)                              \
    if (conf == NGX_CONF_UNSET_UINT) {                                       \
        conf = default;                                                      \
    }

#define ngx_conf_init_size_value(conf, default)                              \
    if (conf == NGX_CONF_UNSET_SIZE) {                                       \
        conf = default;                                                      \
    }

#define ngx_conf_init_msec_value(conf, default)                              \
    if (conf == NGX_CONF_UNSET_MSEC) {                                       \
        conf = default;                                                      \
    }

#define ngx_conf_merge_value(conf, prev, default)                            \
    if (conf == NGX_CONF_UNSET) {                                            \
        conf = (prev == NGX_CONF_UNSET) ? default : prev;                    \
    }

#define ngx_conf_merge_ptr_value(conf, prev, default)                        \
    if (conf == NGX_CONF_UNSET_PTR) {                                        \
        conf = (prev == NGX_CONF_UNSET_PTR) ? default : prev;                \
    }

#define ngx_conf_merge_uint_value(conf, prev, default)                       \
    if (conf == NGX_CONF_UNSET_UINT) {                                       \
        conf = (prev == NGX_CONF_UNSET_UINT) ? default : prev;               \
    }

#define ngx_conf_merge_msec_value(conf, prev, default)                       \
    if (conf == NGX_CONF_UNSET_MSEC) {                                       \
        conf = (prev == NGX_CONF_UNSET_MSEC) ? default : prev;               \
    }

#define ngx_conf_merge_sec_value(conf, prev, default)                        \
    if (conf == NGX_CONF_UNSET) {                                            \
        conf = (prev == NGX_CONF_UNSET) ? default : prev;                    \
    }

#define ngx_conf_merge_size_value(conf, prev, default)                       \
    if (conf == NGX_CONF_UNSET_SIZE) {                                       \
        conf = (prev == NGX_CONF_UNSET_SIZE) ? default : prev;               \
    }

#define ngx_conf_merge_off_value(conf, prev, default)                        \
    if (conf == NGX_CONF_UNSET) {                                            \
        conf = (prev == NGX_CONF_UNSET) ? default : prev;                    \
    }

#define ngx_conf_merge_str_value(conf, prev, default)                        \
    if (conf.data == NULL) {                                                 \
        if (prev.data) {                                                     \
            conf.len = prev.len;                                             \
            conf.data = prev.data;                                           \
        } else {                                                             \
            conf.len = sizeof(default) - 1;                                  \
            conf.data = (u_char *) default;                                  \
        }                                                                    \
    }

#define ngx_conf_merge_bufs_value(conf, prev, default_num, default_size)     \
    if (conf.num == 0) {                                                     \
        if (prev.num) {                                                      \
            conf.num = prev.num;                                             \
            conf.size = prev.size;                                           \
        } else {                                                             \
            conf.num = default_num;                                          \
            conf.size = default_size;                                        \
        }                                                                    \
    }

#define ngx_conf_merge_bitmask_value(conf, prev, default)                    \
    if (conf == 0) {                                                         \
        conf = (prev == 0) ? default : prev;                                 \
    }


char *ngx_conf_param(ngx_conf_t *cf);
char *ngx_conf_parse(ngx_conf_t *cf, ngx_str_t *filename);
char *ngx_conf_include(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);


ngx_int_t ngx_conf_full_name(ngx_cycle_t *cycle, ngx_str_t *name,
    ngx_uint_t conf_prefix);
ngx_open_file_t *ngx_conf_open_file(ngx_cycle_t *cycle, ngx_str_t *name);
void ngx_cdecl ngx_conf_log_error(ngx_uint_t level, ngx_conf_t *cf,
    ngx_err_t err, const char *fmt, ...);


char *ngx_conf_set_flag_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
char *ngx_conf_set_str_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
char *ngx_conf_set_str_array_slot(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
char *ngx_conf_set_keyval_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
char *ngx_conf_set_num_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
char *ngx_conf_set_size_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
char *ngx_conf_set_off_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
char *ngx_conf_set_msec_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
char *ngx_conf_set_sec_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
char *ngx_conf_set_bufs_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
char *ngx_conf_set_enum_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
char *ngx_conf_set_bitmask_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);


extern ngx_uint_t     ngx_max_module;
extern ngx_module_t  *ngx_modules[];


#endif /* _NGX_CONF_FILE_H_INCLUDED_ */