Mercurial > hg > nginx
view src/http/modules/ngx_http_sub_filter_module.c @ 7629:f47f7d3d1bfa
Mp4: fixed possible chunk offset overflow.
In "co64" atom chunk start offset is a 64-bit unsigned integer. When trimming
the "mdat" atom, chunk offsets are casted to off_t values which are typically
64-bit signed integers. A specially crafted mp4 file with huge chunk offsets
may lead to off_t overflow and result in negative trim boundaries.
The consequences of the overflow are:
- Incorrect Content-Length header value in the response.
- Negative left boundary of the response file buffer holding the trimmed "mdat".
This leads to pread()/sendfile() errors followed by closing the client
connection.
On rare systems where off_t is a 32-bit integer, this scenario is also feasible
with the "stco" atom.
The fix is to add checks which make sure data chunks referenced by each track
are within the mp4 file boundaries. Additionally a few more checks are added to
ensure mp4 file consistency and log errors.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Wed, 26 Feb 2020 15:10:46 +0300 |
parents | 201038680680 |
children |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct { ngx_http_complex_value_t match; ngx_http_complex_value_t value; } ngx_http_sub_pair_t; typedef struct { ngx_str_t match; ngx_http_complex_value_t *value; } ngx_http_sub_match_t; typedef struct { ngx_uint_t min_match_len; ngx_uint_t max_match_len; u_char index[257]; u_char shift[256]; } ngx_http_sub_tables_t; typedef struct { ngx_uint_t dynamic; /* unsigned dynamic:1; */ ngx_array_t *pairs; ngx_http_sub_tables_t *tables; ngx_hash_t types; ngx_flag_t once; ngx_flag_t last_modified; ngx_array_t *types_keys; ngx_array_t *matches; } ngx_http_sub_loc_conf_t; typedef struct { ngx_str_t saved; ngx_str_t looked; ngx_uint_t once; /* unsigned once:1 */ ngx_buf_t *buf; u_char *pos; u_char *copy_start; u_char *copy_end; ngx_chain_t *in; ngx_chain_t *out; ngx_chain_t **last_out; ngx_chain_t *busy; ngx_chain_t *free; ngx_str_t *sub; ngx_uint_t applied; ngx_int_t offset; ngx_uint_t index; ngx_http_sub_tables_t *tables; ngx_array_t *matches; } ngx_http_sub_ctx_t; static ngx_uint_t ngx_http_sub_cmp_index; static ngx_int_t ngx_http_sub_output(ngx_http_request_t *r, ngx_http_sub_ctx_t *ctx); static ngx_int_t ngx_http_sub_parse(ngx_http_request_t *r, ngx_http_sub_ctx_t *ctx, ngx_uint_t flush); static ngx_int_t ngx_http_sub_match(ngx_http_sub_ctx_t *ctx, ngx_int_t start, ngx_str_t *m); static char * ngx_http_sub_filter(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static void *ngx_http_sub_create_conf(ngx_conf_t *cf); static char *ngx_http_sub_merge_conf(ngx_conf_t *cf, void *parent, void *child); static void ngx_http_sub_init_tables(ngx_http_sub_tables_t *tables, ngx_http_sub_match_t *match, ngx_uint_t n); static ngx_int_t ngx_http_sub_cmp_matches(const void *one, const void *two); static ngx_int_t ngx_http_sub_filter_init(ngx_conf_t *cf); static ngx_command_t ngx_http_sub_filter_commands[] = { { ngx_string("sub_filter"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2, ngx_http_sub_filter, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL }, { ngx_string("sub_filter_types"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE, ngx_http_types_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_sub_loc_conf_t, types_keys), &ngx_http_html_default_types[0] }, { ngx_string("sub_filter_once"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG, ngx_conf_set_flag_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_sub_loc_conf_t, once), NULL }, { ngx_string("sub_filter_last_modified"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG, ngx_conf_set_flag_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_sub_loc_conf_t, last_modified), NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_sub_filter_module_ctx = { NULL, /* preconfiguration */ ngx_http_sub_filter_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_sub_create_conf, /* create location configuration */ ngx_http_sub_merge_conf /* merge location configuration */ }; ngx_module_t ngx_http_sub_filter_module = { NGX_MODULE_V1, &ngx_http_sub_filter_module_ctx, /* module context */ ngx_http_sub_filter_commands, /* module directives */ NGX_HTTP_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 ngx_http_output_header_filter_pt ngx_http_next_header_filter; static ngx_http_output_body_filter_pt ngx_http_next_body_filter; static ngx_int_t ngx_http_sub_header_filter(ngx_http_request_t *r) { ngx_str_t *m; ngx_uint_t i, j, n; ngx_http_sub_ctx_t *ctx; ngx_http_sub_pair_t *pairs; ngx_http_sub_match_t *matches; ngx_http_sub_loc_conf_t *slcf; slcf = ngx_http_get_module_loc_conf(r, ngx_http_sub_filter_module); if (slcf->pairs == NULL || r->headers_out.content_length_n == 0 || ngx_http_test_content_type(r, &slcf->types) == NULL) { return ngx_http_next_header_filter(r); } ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_sub_ctx_t)); if (ctx == NULL) { return NGX_ERROR; } if (slcf->dynamic == 0) { ctx->tables = slcf->tables; ctx->matches = slcf->matches; } else { pairs = slcf->pairs->elts; n = slcf->pairs->nelts; matches = ngx_pcalloc(r->pool, sizeof(ngx_http_sub_match_t) * n); if (matches == NULL) { return NGX_ERROR; } j = 0; for (i = 0; i < n; i++) { matches[j].value = &pairs[i].value; if (pairs[i].match.lengths == NULL) { matches[j].match = pairs[i].match.value; j++; continue; } m = &matches[j].match; if (ngx_http_complex_value(r, &pairs[i].match, m) != NGX_OK) { return NGX_ERROR; } if (m->len == 0) { continue; } ngx_strlow(m->data, m->data, m->len); j++; } if (j == 0) { return ngx_http_next_header_filter(r); } ctx->matches = ngx_palloc(r->pool, sizeof(ngx_array_t)); if (ctx->matches == NULL) { return NGX_ERROR; } ctx->matches->elts = matches; ctx->matches->nelts = j; ctx->tables = ngx_palloc(r->pool, sizeof(ngx_http_sub_tables_t)); if (ctx->tables == NULL) { return NGX_ERROR; } ngx_http_sub_init_tables(ctx->tables, ctx->matches->elts, ctx->matches->nelts); } ctx->saved.data = ngx_pnalloc(r->pool, ctx->tables->max_match_len - 1); if (ctx->saved.data == NULL) { return NGX_ERROR; } ctx->looked.data = ngx_pnalloc(r->pool, ctx->tables->max_match_len - 1); if (ctx->looked.data == NULL) { return NGX_ERROR; } ngx_http_set_ctx(r, ctx, ngx_http_sub_filter_module); ctx->offset = ctx->tables->min_match_len - 1; ctx->last_out = &ctx->out; r->filter_need_in_memory = 1; if (r == r->main) { ngx_http_clear_content_length(r); if (!slcf->last_modified) { ngx_http_clear_last_modified(r); ngx_http_clear_etag(r); } else { ngx_http_weak_etag(r); } } return ngx_http_next_header_filter(r); } static ngx_int_t ngx_http_sub_body_filter(ngx_http_request_t *r, ngx_chain_t *in) { ngx_int_t rc; ngx_buf_t *b; ngx_str_t *sub; ngx_uint_t flush, last; ngx_chain_t *cl; ngx_http_sub_ctx_t *ctx; ngx_http_sub_match_t *match; ngx_http_sub_loc_conf_t *slcf; ctx = ngx_http_get_module_ctx(r, ngx_http_sub_filter_module); if (ctx == NULL) { return ngx_http_next_body_filter(r, in); } if ((in == NULL && ctx->buf == NULL && ctx->in == NULL && ctx->busy == NULL)) { return ngx_http_next_body_filter(r, in); } if (ctx->once && (ctx->buf == NULL || ctx->in == NULL)) { if (ctx->busy) { if (ngx_http_sub_output(r, ctx) == NGX_ERROR) { return NGX_ERROR; } } return ngx_http_next_body_filter(r, in); } /* add the incoming chain to the chain ctx->in */ if (in) { if (ngx_chain_add_copy(r->pool, &ctx->in, in) != NGX_OK) { return NGX_ERROR; } } ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http sub filter \"%V\"", &r->uri); flush = 0; last = 0; while (ctx->in || ctx->buf) { if (ctx->buf == NULL) { ctx->buf = ctx->in->buf; ctx->in = ctx->in->next; ctx->pos = ctx->buf->pos; } if (ctx->buf->flush || ctx->buf->recycled) { flush = 1; } if (ctx->in == NULL) { last = flush; } b = NULL; while (ctx->pos < ctx->buf->last) { rc = ngx_http_sub_parse(r, ctx, last); ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "parse: %i, looked: \"%V\" %p-%p", rc, &ctx->looked, ctx->copy_start, ctx->copy_end); if (rc == NGX_ERROR) { return rc; } if (ctx->saved.len) { ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "saved: \"%V\"", &ctx->saved); cl = ngx_chain_get_free_buf(r->pool, &ctx->free); if (cl == NULL) { return NGX_ERROR; } b = cl->buf; ngx_memzero(b, sizeof(ngx_buf_t)); b->pos = ngx_pnalloc(r->pool, ctx->saved.len); if (b->pos == NULL) { return NGX_ERROR; } ngx_memcpy(b->pos, ctx->saved.data, ctx->saved.len); b->last = b->pos + ctx->saved.len; b->memory = 1; *ctx->last_out = cl; ctx->last_out = &cl->next; ctx->saved.len = 0; } if (ctx->copy_start != ctx->copy_end) { cl = ngx_chain_get_free_buf(r->pool, &ctx->free); if (cl == NULL) { return NGX_ERROR; } b = cl->buf; ngx_memcpy(b, ctx->buf, sizeof(ngx_buf_t)); b->pos = ctx->copy_start; b->last = ctx->copy_end; b->shadow = NULL; b->last_buf = 0; b->last_in_chain = 0; b->recycled = 0; if (b->in_file) { b->file_last = b->file_pos + (b->last - ctx->buf->pos); b->file_pos += b->pos - ctx->buf->pos; } *ctx->last_out = cl; ctx->last_out = &cl->next; } if (rc == NGX_AGAIN) { continue; } /* rc == NGX_OK */ cl = ngx_chain_get_free_buf(r->pool, &ctx->free); if (cl == NULL) { return NGX_ERROR; } b = cl->buf; ngx_memzero(b, sizeof(ngx_buf_t)); slcf = ngx_http_get_module_loc_conf(r, ngx_http_sub_filter_module); if (ctx->sub == NULL) { ctx->sub = ngx_pcalloc(r->pool, sizeof(ngx_str_t) * ctx->matches->nelts); if (ctx->sub == NULL) { return NGX_ERROR; } } sub = &ctx->sub[ctx->index]; if (sub->data == NULL) { match = ctx->matches->elts; if (ngx_http_complex_value(r, match[ctx->index].value, sub) != NGX_OK) { return NGX_ERROR; } } if (sub->len) { b->memory = 1; b->pos = sub->data; b->last = sub->data + sub->len; } else { b->sync = 1; } *ctx->last_out = cl; ctx->last_out = &cl->next; ctx->index = 0; ctx->once = slcf->once && (++ctx->applied == ctx->matches->nelts); continue; } if (ctx->looked.len && (ctx->buf->last_buf || ctx->buf->last_in_chain)) { cl = ngx_chain_get_free_buf(r->pool, &ctx->free); if (cl == NULL) { return NGX_ERROR; } b = cl->buf; ngx_memzero(b, sizeof(ngx_buf_t)); b->pos = ctx->looked.data; b->last = b->pos + ctx->looked.len; b->memory = 1; *ctx->last_out = cl; ctx->last_out = &cl->next; ctx->looked.len = 0; } if (ctx->buf->last_buf || ctx->buf->flush || ctx->buf->sync || ngx_buf_in_memory(ctx->buf)) { if (b == NULL) { cl = ngx_chain_get_free_buf(r->pool, &ctx->free); if (cl == NULL) { return NGX_ERROR; } b = cl->buf; ngx_memzero(b, sizeof(ngx_buf_t)); b->sync = 1; *ctx->last_out = cl; ctx->last_out = &cl->next; } b->last_buf = ctx->buf->last_buf; b->last_in_chain = ctx->buf->last_in_chain; b->flush = ctx->buf->flush; b->shadow = ctx->buf; b->recycled = ctx->buf->recycled; } ctx->buf = NULL; } if (ctx->out == NULL && ctx->busy == NULL) { return NGX_OK; } return ngx_http_sub_output(r, ctx); } static ngx_int_t ngx_http_sub_output(ngx_http_request_t *r, ngx_http_sub_ctx_t *ctx) { ngx_int_t rc; ngx_buf_t *b; ngx_chain_t *cl; #if 1 b = NULL; for (cl = ctx->out; cl; cl = cl->next) { ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "sub out: %p %p", cl->buf, cl->buf->pos); if (cl->buf == b) { ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0, "the same buf was used in sub"); ngx_debug_point(); return NGX_ERROR; } b = cl->buf; } #endif rc = ngx_http_next_body_filter(r, ctx->out); if (ctx->busy == NULL) { ctx->busy = ctx->out; } else { for (cl = ctx->busy; cl->next; cl = cl->next) { /* void */ } cl->next = ctx->out; } ctx->out = NULL; ctx->last_out = &ctx->out; while (ctx->busy) { cl = ctx->busy; b = cl->buf; if (ngx_buf_size(b) != 0) { break; } if (b->shadow) { b->shadow->pos = b->shadow->last; } ctx->busy = cl->next; if (ngx_buf_in_memory(b) || b->in_file) { /* add data bufs only to the free buf chain */ cl->next = ctx->free; ctx->free = cl; } } if (ctx->in || ctx->buf) { r->buffered |= NGX_HTTP_SUB_BUFFERED; } else { r->buffered &= ~NGX_HTTP_SUB_BUFFERED; } return rc; } static ngx_int_t ngx_http_sub_parse(ngx_http_request_t *r, ngx_http_sub_ctx_t *ctx, ngx_uint_t flush) { u_char *p, c; ngx_str_t *m; ngx_int_t offset, start, next, end, len, rc; ngx_uint_t shift, i, j; ngx_http_sub_match_t *match; ngx_http_sub_tables_t *tables; ngx_http_sub_loc_conf_t *slcf; slcf = ngx_http_get_module_loc_conf(r, ngx_http_sub_filter_module); tables = ctx->tables; match = ctx->matches->elts; offset = ctx->offset; end = ctx->buf->last - ctx->pos; if (ctx->once) { /* sets start and next to end */ offset = end + (ngx_int_t) tables->min_match_len - 1; goto again; } while (offset < end) { c = offset < 0 ? ctx->looked.data[ctx->looked.len + offset] : ctx->pos[offset]; c = ngx_tolower(c); shift = tables->shift[c]; if (shift > 0) { offset += shift; continue; } /* a potential match */ start = offset - (ngx_int_t) tables->min_match_len + 1; i = ngx_max((ngx_uint_t) tables->index[c], ctx->index); j = tables->index[c + 1]; while (i != j) { if (slcf->once && ctx->sub && ctx->sub[i].data) { goto next; } m = &match[i].match; rc = ngx_http_sub_match(ctx, start, m); if (rc == NGX_DECLINED) { goto next; } ctx->index = i; if (rc == NGX_AGAIN) { goto again; } ctx->offset = offset + (ngx_int_t) m->len; next = start + (ngx_int_t) m->len; end = ngx_max(next, 0); rc = NGX_OK; goto done; next: i++; } offset++; ctx->index = 0; } if (flush) { for ( ;; ) { start = offset - (ngx_int_t) tables->min_match_len + 1; if (start >= end) { break; } for (i = 0; i < ctx->matches->nelts; i++) { m = &match[i].match; if (ngx_http_sub_match(ctx, start, m) == NGX_AGAIN) { goto again; } } offset++; } } again: ctx->offset = offset; start = offset - (ngx_int_t) tables->min_match_len + 1; next = start; rc = NGX_AGAIN; done: /* send [ - looked.len, start ] to client */ ctx->saved.len = ctx->looked.len + ngx_min(start, 0); ngx_memcpy(ctx->saved.data, ctx->looked.data, ctx->saved.len); ctx->copy_start = ctx->pos; ctx->copy_end = ctx->pos + ngx_max(start, 0); /* save [ next, end ] in looked */ len = ngx_min(next, 0); p = ctx->looked.data; p = ngx_movemem(p, p + ctx->looked.len + len, - len); len = ngx_max(next, 0); p = ngx_cpymem(p, ctx->pos + len, end - len); ctx->looked.len = p - ctx->looked.data; /* update position */ ctx->pos += end; ctx->offset -= end; return rc; } static ngx_int_t ngx_http_sub_match(ngx_http_sub_ctx_t *ctx, ngx_int_t start, ngx_str_t *m) { u_char *p, *last, *pat, *pat_end; pat = m->data; pat_end = m->data + m->len; if (start >= 0) { p = ctx->pos + start; } else { last = ctx->looked.data + ctx->looked.len; p = last + start; while (p < last && pat < pat_end) { if (ngx_tolower(*p) != *pat) { return NGX_DECLINED; } p++; pat++; } p = ctx->pos; } while (p < ctx->buf->last && pat < pat_end) { if (ngx_tolower(*p) != *pat) { return NGX_DECLINED; } p++; pat++; } if (pat != pat_end) { /* partial match */ return NGX_AGAIN; } return NGX_OK; } static char * ngx_http_sub_filter(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_sub_loc_conf_t *slcf = conf; ngx_str_t *value; ngx_http_sub_pair_t *pair; ngx_http_compile_complex_value_t ccv; value = cf->args->elts; if (value[1].len == 0) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "empty search pattern"); return NGX_CONF_ERROR; } if (slcf->pairs == NULL) { slcf->pairs = ngx_array_create(cf->pool, 1, sizeof(ngx_http_sub_pair_t)); if (slcf->pairs == NULL) { return NGX_CONF_ERROR; } } if (slcf->pairs->nelts == 255) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "number of search patterns exceeds 255"); return NGX_CONF_ERROR; } ngx_strlow(value[1].data, value[1].data, value[1].len); pair = ngx_array_push(slcf->pairs); if (pair == NULL) { return NGX_CONF_ERROR; } ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t)); ccv.cf = cf; ccv.value = &value[1]; ccv.complex_value = &pair->match; if (ngx_http_compile_complex_value(&ccv) != NGX_OK) { return NGX_CONF_ERROR; } if (ccv.complex_value->lengths != NULL) { slcf->dynamic = 1; } else { ngx_strlow(pair->match.value.data, pair->match.value.data, pair->match.value.len); } ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t)); ccv.cf = cf; ccv.value = &value[2]; ccv.complex_value = &pair->value; if (ngx_http_compile_complex_value(&ccv) != NGX_OK) { return NGX_CONF_ERROR; } return NGX_CONF_OK; } static void * ngx_http_sub_create_conf(ngx_conf_t *cf) { ngx_http_sub_loc_conf_t *slcf; slcf = ngx_pcalloc(cf->pool, sizeof(ngx_http_sub_loc_conf_t)); if (slcf == NULL) { return NULL; } /* * set by ngx_pcalloc(): * * conf->dynamic = 0; * conf->pairs = NULL; * conf->tables = NULL; * conf->types = { NULL }; * conf->types_keys = NULL; * conf->matches = NULL; */ slcf->once = NGX_CONF_UNSET; slcf->last_modified = NGX_CONF_UNSET; return slcf; } static char * ngx_http_sub_merge_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_uint_t i, n; ngx_http_sub_pair_t *pairs; ngx_http_sub_match_t *matches; ngx_http_sub_loc_conf_t *prev = parent; ngx_http_sub_loc_conf_t *conf = child; ngx_conf_merge_value(conf->once, prev->once, 1); ngx_conf_merge_value(conf->last_modified, prev->last_modified, 0); if (ngx_http_merge_types(cf, &conf->types_keys, &conf->types, &prev->types_keys, &prev->types, ngx_http_html_default_types) != NGX_OK) { return NGX_CONF_ERROR; } if (conf->pairs == NULL) { conf->dynamic = prev->dynamic; conf->pairs = prev->pairs; conf->matches = prev->matches; conf->tables = prev->tables; } if (conf->pairs && conf->dynamic == 0 && conf->tables == NULL) { pairs = conf->pairs->elts; n = conf->pairs->nelts; matches = ngx_palloc(cf->pool, sizeof(ngx_http_sub_match_t) * n); if (matches == NULL) { return NGX_CONF_ERROR; } for (i = 0; i < n; i++) { matches[i].match = pairs[i].match.value; matches[i].value = &pairs[i].value; } conf->matches = ngx_palloc(cf->pool, sizeof(ngx_array_t)); if (conf->matches == NULL) { return NGX_CONF_ERROR; } conf->matches->elts = matches; conf->matches->nelts = n; conf->tables = ngx_palloc(cf->pool, sizeof(ngx_http_sub_tables_t)); if (conf->tables == NULL) { return NGX_CONF_ERROR; } ngx_http_sub_init_tables(conf->tables, conf->matches->elts, conf->matches->nelts); } return NGX_CONF_OK; } static void ngx_http_sub_init_tables(ngx_http_sub_tables_t *tables, ngx_http_sub_match_t *match, ngx_uint_t n) { u_char c; ngx_uint_t i, j, min, max, ch; min = match[0].match.len; max = match[0].match.len; for (i = 1; i < n; i++) { min = ngx_min(min, match[i].match.len); max = ngx_max(max, match[i].match.len); } tables->min_match_len = min; tables->max_match_len = max; ngx_http_sub_cmp_index = tables->min_match_len - 1; ngx_sort(match, n, sizeof(ngx_http_sub_match_t), ngx_http_sub_cmp_matches); min = ngx_min(min, 255); ngx_memset(tables->shift, min, 256); ch = 0; for (i = 0; i < n; i++) { for (j = 0; j < min; j++) { c = match[i].match.data[tables->min_match_len - 1 - j]; tables->shift[c] = ngx_min(tables->shift[c], (u_char) j); } c = match[i].match.data[tables->min_match_len - 1]; while (ch <= (ngx_uint_t) c) { tables->index[ch++] = (u_char) i; } } while (ch < 257) { tables->index[ch++] = (u_char) n; } } static ngx_int_t ngx_http_sub_cmp_matches(const void *one, const void *two) { ngx_int_t c1, c2; ngx_http_sub_match_t *first, *second; first = (ngx_http_sub_match_t *) one; second = (ngx_http_sub_match_t *) two; c1 = first->match.data[ngx_http_sub_cmp_index]; c2 = second->match.data[ngx_http_sub_cmp_index]; return c1 - c2; } static ngx_int_t ngx_http_sub_filter_init(ngx_conf_t *cf) { ngx_http_next_header_filter = ngx_http_top_header_filter; ngx_http_top_header_filter = ngx_http_sub_header_filter; ngx_http_next_body_filter = ngx_http_top_body_filter; ngx_http_top_body_filter = ngx_http_sub_body_filter; return NGX_OK; }