Mercurial > hg > nginx
view src/http/modules/ngx_http_slice_filter_module.c @ 9300:5be23505292b
SSI: fixed incorrect or duplicate stub output.
Following 3518:eb3aaf8bd2a9 (0.8.37), r->request_output is only set
if there are data in the first buffer sent in the subrequest. As a
result, following the change mentioned this flag cannot be used to
prevent duplicate ngx_http_ssi_stub_output() calls, since it is not
set if there was already some output, but the first buffer was empty.
Still, when there are multiple subrequests, even an empty subrequest
response might be delayed by the postpone filter, leading to a second
call of ngx_http_ssi_stub_output() during finalization from
ngx_http_writer() the subreqest buffers are released by the postpone
filter. Since r->request_output is not set after the first call, this
resulted in duplicate stub output.
Additionally, checking only the first buffer might be wrong in some
unusual cases. For example, the first buffer might be empty if
$r->flush() is called before printing any data in the embedded Perl
module.
Depending on the postpone_output value and corresponding sizes, this
issue can result in either duplicate or unexpected stub output, or
"zero size buf in writer" alerts.
Following 8124:f5515e727656 (1.23.4), it became slightly easier to
reproduce the issue, as empty static files and empty cache items now
result in a response with an empty buffer. Before the change, an empty
proxied response can be used to reproduce the issue.
Fix is check all buffers and set r->request_output if any non-empty
buffers are sent. This ensures that all unusual cases of non-empty
responses are covered, and also that r->request_output will be set
after the first stub output, preventing duplicate output.
Reported by Jan Gassen.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 04 Jul 2024 17:41:28 +0300 |
parents | 32a343635b50 |
children |
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/* * Copyright (C) Roman Arutyunyan * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct { size_t size; } ngx_http_slice_loc_conf_t; typedef struct { off_t start; off_t end; ngx_str_t range; ngx_str_t etag; unsigned last:1; unsigned active:1; ngx_http_request_t *sr; } ngx_http_slice_ctx_t; typedef struct { off_t start; off_t end; off_t complete_length; } ngx_http_slice_content_range_t; static ngx_int_t ngx_http_slice_header_filter(ngx_http_request_t *r); static ngx_int_t ngx_http_slice_body_filter(ngx_http_request_t *r, ngx_chain_t *in); static ngx_int_t ngx_http_slice_parse_content_range(ngx_http_request_t *r, ngx_http_slice_content_range_t *cr); static ngx_int_t ngx_http_slice_range_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data); static off_t ngx_http_slice_get_start(ngx_http_request_t *r); static void *ngx_http_slice_create_loc_conf(ngx_conf_t *cf); static char *ngx_http_slice_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child); static ngx_int_t ngx_http_slice_add_variables(ngx_conf_t *cf); static ngx_int_t ngx_http_slice_init(ngx_conf_t *cf); static ngx_command_t ngx_http_slice_filter_commands[] = { { ngx_string("slice"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_size_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_slice_loc_conf_t, size), NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_slice_filter_module_ctx = { ngx_http_slice_add_variables, /* preconfiguration */ ngx_http_slice_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_slice_create_loc_conf, /* create location configuration */ ngx_http_slice_merge_loc_conf /* merge location configuration */ }; ngx_module_t ngx_http_slice_filter_module = { NGX_MODULE_V1, &ngx_http_slice_filter_module_ctx, /* module context */ ngx_http_slice_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_str_t ngx_http_slice_range_name = ngx_string("slice_range"); 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_slice_header_filter(ngx_http_request_t *r) { off_t end; ngx_int_t rc; ngx_table_elt_t *h; ngx_http_slice_ctx_t *ctx; ngx_http_slice_loc_conf_t *slcf; ngx_http_slice_content_range_t cr; ctx = ngx_http_get_module_ctx(r, ngx_http_slice_filter_module); if (ctx == NULL) { return ngx_http_next_header_filter(r); } if (r->headers_out.status != NGX_HTTP_PARTIAL_CONTENT) { if (r == r->main) { ngx_http_set_ctx(r, NULL, ngx_http_slice_filter_module); return ngx_http_next_header_filter(r); } ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "unexpected status code %ui in slice response", r->headers_out.status); return NGX_ERROR; } h = r->headers_out.etag; if (ctx->etag.len) { if (h == NULL || h->value.len != ctx->etag.len || ngx_strncmp(h->value.data, ctx->etag.data, ctx->etag.len) != 0) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "etag mismatch in slice response"); return NGX_ERROR; } } if (h) { ctx->etag = h->value; } if (ngx_http_slice_parse_content_range(r, &cr) != NGX_OK) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "invalid range in slice response"); return NGX_ERROR; } if (cr.complete_length == -1) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "no complete length in slice response"); return NGX_ERROR; } ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http slice response range: %O-%O/%O", cr.start, cr.end, cr.complete_length); slcf = ngx_http_get_module_loc_conf(r, ngx_http_slice_filter_module); end = ngx_min(cr.start + (off_t) slcf->size, cr.complete_length); if (cr.start != ctx->start || cr.end != end) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "unexpected range in slice response: %O-%O", cr.start, cr.end); return NGX_ERROR; } ctx->start = end; ctx->active = 1; r->headers_out.status = NGX_HTTP_OK; r->headers_out.status_line.len = 0; r->headers_out.content_length_n = cr.complete_length; r->headers_out.content_offset = cr.start; r->headers_out.content_range->hash = 0; r->headers_out.content_range = NULL; if (r->headers_out.accept_ranges) { r->headers_out.accept_ranges->hash = 0; r->headers_out.accept_ranges = NULL; } r->allow_ranges = 1; r->subrequest_ranges = 1; r->single_range = 1; rc = ngx_http_next_header_filter(r); if (r != r->main) { return rc; } r->preserve_body = 1; if (r->headers_out.status == NGX_HTTP_PARTIAL_CONTENT) { if (ctx->start + (off_t) slcf->size <= r->headers_out.content_offset) { ctx->start = slcf->size * (r->headers_out.content_offset / slcf->size); } ctx->end = r->headers_out.content_offset + r->headers_out.content_length_n; } else { ctx->end = cr.complete_length; } return rc; } static ngx_int_t ngx_http_slice_body_filter(ngx_http_request_t *r, ngx_chain_t *in) { ngx_int_t rc; ngx_chain_t *cl; ngx_http_slice_ctx_t *ctx; ngx_http_slice_loc_conf_t *slcf; ctx = ngx_http_get_module_ctx(r, ngx_http_slice_filter_module); if (ctx == NULL || r != r->main) { return ngx_http_next_body_filter(r, in); } for (cl = in; cl; cl = cl->next) { if (cl->buf->last_buf) { cl->buf->last_buf = 0; cl->buf->last_in_chain = 1; cl->buf->sync = 1; ctx->last = 1; } } rc = ngx_http_next_body_filter(r, in); if (rc == NGX_ERROR || !ctx->last) { return rc; } if (ctx->sr && !ctx->sr->done) { return rc; } if (!ctx->active) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "missing slice response"); return NGX_ERROR; } if (ctx->start >= ctx->end) { ngx_http_set_ctx(r, NULL, ngx_http_slice_filter_module); ngx_http_send_special(r, NGX_HTTP_LAST); return rc; } if (r->buffered) { return rc; } if (ngx_http_subrequest(r, &r->uri, &r->args, &ctx->sr, NULL, NGX_HTTP_SUBREQUEST_CLONE) != NGX_OK) { return NGX_ERROR; } ngx_http_set_ctx(ctx->sr, ctx, ngx_http_slice_filter_module); slcf = ngx_http_get_module_loc_conf(r, ngx_http_slice_filter_module); ctx->range.len = ngx_sprintf(ctx->range.data, "bytes=%O-%O", ctx->start, ctx->start + (off_t) slcf->size - 1) - ctx->range.data; ctx->active = 0; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http slice subrequest: \"%V\"", &ctx->range); return rc; } static ngx_int_t ngx_http_slice_parse_content_range(ngx_http_request_t *r, ngx_http_slice_content_range_t *cr) { off_t start, end, complete_length, cutoff, cutlim; u_char *p; ngx_table_elt_t *h; h = r->headers_out.content_range; if (h == NULL || h->value.len < 7 || ngx_strncmp(h->value.data, "bytes ", 6) != 0) { return NGX_ERROR; } p = h->value.data + 6; cutoff = NGX_MAX_OFF_T_VALUE / 10; cutlim = NGX_MAX_OFF_T_VALUE % 10; start = 0; end = 0; complete_length = 0; while (*p == ' ') { p++; } if (*p < '0' || *p > '9') { return NGX_ERROR; } while (*p >= '0' && *p <= '9') { if (start >= cutoff && (start > cutoff || *p - '0' > cutlim)) { return NGX_ERROR; } start = start * 10 + (*p++ - '0'); } while (*p == ' ') { p++; } if (*p++ != '-') { return NGX_ERROR; } while (*p == ' ') { p++; } if (*p < '0' || *p > '9') { return NGX_ERROR; } while (*p >= '0' && *p <= '9') { if (end >= cutoff && (end > cutoff || *p - '0' > cutlim)) { return NGX_ERROR; } end = end * 10 + (*p++ - '0'); } end++; while (*p == ' ') { p++; } if (*p++ != '/') { return NGX_ERROR; } while (*p == ' ') { p++; } if (*p != '*') { if (*p < '0' || *p > '9') { return NGX_ERROR; } while (*p >= '0' && *p <= '9') { if (complete_length >= cutoff && (complete_length > cutoff || *p - '0' > cutlim)) { return NGX_ERROR; } complete_length = complete_length * 10 + (*p++ - '0'); } } else { complete_length = -1; p++; } while (*p == ' ') { p++; } if (*p != '\0') { return NGX_ERROR; } cr->start = start; cr->end = end; cr->complete_length = complete_length; return NGX_OK; } static ngx_int_t ngx_http_slice_range_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data) { u_char *p; ngx_http_slice_ctx_t *ctx; ngx_http_slice_loc_conf_t *slcf; ctx = ngx_http_get_module_ctx(r, ngx_http_slice_filter_module); if (ctx == NULL) { if (r != r->main || r->headers_out.status) { v->not_found = 1; return NGX_OK; } slcf = ngx_http_get_module_loc_conf(r, ngx_http_slice_filter_module); if (slcf->size == 0) { v->not_found = 1; return NGX_OK; } ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_slice_ctx_t)); if (ctx == NULL) { return NGX_ERROR; } ngx_http_set_ctx(r, ctx, ngx_http_slice_filter_module); p = ngx_pnalloc(r->pool, sizeof("bytes=-") - 1 + 2 * NGX_OFF_T_LEN); if (p == NULL) { return NGX_ERROR; } ctx->start = slcf->size * (ngx_http_slice_get_start(r) / slcf->size); ctx->range.data = p; ctx->range.len = ngx_sprintf(p, "bytes=%O-%O", ctx->start, ctx->start + (off_t) slcf->size - 1) - p; } v->data = ctx->range.data; v->valid = 1; v->not_found = 0; v->no_cacheable = 1; v->len = ctx->range.len; return NGX_OK; } static off_t ngx_http_slice_get_start(ngx_http_request_t *r) { off_t start, cutoff, cutlim; u_char *p; ngx_table_elt_t *h; if (r->headers_in.if_range) { return 0; } h = r->headers_in.range; if (h == NULL || h->value.len < 7 || ngx_strncasecmp(h->value.data, (u_char *) "bytes=", 6) != 0) { return 0; } p = h->value.data + 6; if (ngx_strchr(p, ',')) { return 0; } while (*p == ' ') { p++; } if (*p == '-') { return 0; } cutoff = NGX_MAX_OFF_T_VALUE / 10; cutlim = NGX_MAX_OFF_T_VALUE % 10; start = 0; while (*p >= '0' && *p <= '9') { if (start >= cutoff && (start > cutoff || *p - '0' > cutlim)) { return 0; } start = start * 10 + (*p++ - '0'); } return start; } static void * ngx_http_slice_create_loc_conf(ngx_conf_t *cf) { ngx_http_slice_loc_conf_t *slcf; slcf = ngx_palloc(cf->pool, sizeof(ngx_http_slice_loc_conf_t)); if (slcf == NULL) { return NULL; } slcf->size = NGX_CONF_UNSET_SIZE; return slcf; } static char * ngx_http_slice_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_slice_loc_conf_t *prev = parent; ngx_http_slice_loc_conf_t *conf = child; ngx_conf_merge_size_value(conf->size, prev->size, 0); return NGX_CONF_OK; } static ngx_int_t ngx_http_slice_add_variables(ngx_conf_t *cf) { ngx_http_variable_t *var; var = ngx_http_add_variable(cf, &ngx_http_slice_range_name, 0); if (var == NULL) { return NGX_ERROR; } var->get_handler = ngx_http_slice_range_variable; return NGX_OK; } static ngx_int_t ngx_http_slice_init(ngx_conf_t *cf) { ngx_http_next_header_filter = ngx_http_top_header_filter; ngx_http_top_header_filter = ngx_http_slice_header_filter; ngx_http_next_body_filter = ngx_http_top_body_filter; ngx_http_top_body_filter = ngx_http_slice_body_filter; return NGX_OK; }