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view src/stream/ngx_stream_write_filter_module.c @ 7690:8253424d1aff

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Added size check to ngx_http_alloc_large_header_buffer(). This ensures that copying won't write more than the buffer size even if the buffer comes from hc->free and it is smaller than the large client header buffer size in the virtual host configuration. This might happen if size of large client header buffers is different in name-based virtual hosts, similarly to the problem with number of buffers fixed in 6926:e662cbf1b932.
author Maxim Dounin <mdounin@mdounin.ru>
date Thu, 06 Aug 2020 05:02:22 +0300
parents d127837c714f
children 32b0ba4855a6
line wrap: on
line source


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


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


typedef struct {
    ngx_chain_t  *from_upstream;
    ngx_chain_t  *from_downstream;
} ngx_stream_write_filter_ctx_t;


static ngx_int_t ngx_stream_write_filter(ngx_stream_session_t *s,
    ngx_chain_t *in, ngx_uint_t from_upstream);
static ngx_int_t ngx_stream_write_filter_init(ngx_conf_t *cf);


static ngx_stream_module_t  ngx_stream_write_filter_module_ctx = {
    NULL,                                  /* preconfiguration */
    ngx_stream_write_filter_init,          /* postconfiguration */

    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

    NULL,                                  /* create server configuration */
    NULL                                   /* merge server configuration */
};


ngx_module_t  ngx_stream_write_filter_module = {
    NGX_MODULE_V1,
    &ngx_stream_write_filter_module_ctx,   /* module context */
    NULL,                                  /* module directives */
    NGX_STREAM_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_int_t
ngx_stream_write_filter(ngx_stream_session_t *s, ngx_chain_t *in,
    ngx_uint_t from_upstream)
{
    off_t                           size;
    ngx_uint_t                      last, flush, sync;
    ngx_chain_t                    *cl, *ln, **ll, **out, *chain;
    ngx_connection_t               *c;
    ngx_stream_write_filter_ctx_t  *ctx;

    ctx = ngx_stream_get_module_ctx(s, ngx_stream_write_filter_module);

    if (ctx == NULL) {
        ctx = ngx_pcalloc(s->connection->pool,
                          sizeof(ngx_stream_write_filter_ctx_t));
        if (ctx == NULL) {
            return NGX_ERROR;
        }

        ngx_stream_set_ctx(s, ctx, ngx_stream_write_filter_module);
    }

    if (from_upstream) {
        c = s->connection;
        out = &ctx->from_upstream;

    } else {
        c = s->upstream->peer.connection;
        out = &ctx->from_downstream;
    }

    if (c->error) {
        return NGX_ERROR;
    }

    size = 0;
    flush = 0;
    sync = 0;
    last = 0;
    ll = out;

    /* find the size, the flush point and the last link of the saved chain */

    for (cl = *out; cl; cl = cl->next) {
        ll = &cl->next;

        ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0,
                       "write old buf t:%d f:%d %p, pos %p, size: %z "
                       "file: %O, size: %O",
                       cl->buf->temporary, cl->buf->in_file,
                       cl->buf->start, cl->buf->pos,
                       cl->buf->last - cl->buf->pos,
                       cl->buf->file_pos,
                       cl->buf->file_last - cl->buf->file_pos);

        if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) {
            ngx_log_error(NGX_LOG_ALERT, c->log, 0,
                          "zero size buf in writer "
                          "t:%d r:%d f:%d %p %p-%p %p %O-%O",
                          cl->buf->temporary,
                          cl->buf->recycled,
                          cl->buf->in_file,
                          cl->buf->start,
                          cl->buf->pos,
                          cl->buf->last,
                          cl->buf->file,
                          cl->buf->file_pos,
                          cl->buf->file_last);

            ngx_debug_point();
            return NGX_ERROR;
        }

        if (ngx_buf_size(cl->buf) < 0) {
            ngx_log_error(NGX_LOG_ALERT, c->log, 0,
                          "negative size buf in writer "
                          "t:%d r:%d f:%d %p %p-%p %p %O-%O",
                          cl->buf->temporary,
                          cl->buf->recycled,
                          cl->buf->in_file,
                          cl->buf->start,
                          cl->buf->pos,
                          cl->buf->last,
                          cl->buf->file,
                          cl->buf->file_pos,
                          cl->buf->file_last);

            ngx_debug_point();
            return NGX_ERROR;
        }

        size += ngx_buf_size(cl->buf);

        if (cl->buf->flush || cl->buf->recycled) {
            flush = 1;
        }

        if (cl->buf->sync) {
            sync = 1;
        }

        if (cl->buf->last_buf) {
            last = 1;
        }
    }

    /* add the new chain to the existent one */

    for (ln = in; ln; ln = ln->next) {
        cl = ngx_alloc_chain_link(c->pool);
        if (cl == NULL) {
            return NGX_ERROR;
        }

        cl->buf = ln->buf;
        *ll = cl;
        ll = &cl->next;

        ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0,
                       "write new buf t:%d f:%d %p, pos %p, size: %z "
                       "file: %O, size: %O",
                       cl->buf->temporary, cl->buf->in_file,
                       cl->buf->start, cl->buf->pos,
                       cl->buf->last - cl->buf->pos,
                       cl->buf->file_pos,
                       cl->buf->file_last - cl->buf->file_pos);

        if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) {
            ngx_log_error(NGX_LOG_ALERT, c->log, 0,
                          "zero size buf in writer "
                          "t:%d r:%d f:%d %p %p-%p %p %O-%O",
                          cl->buf->temporary,
                          cl->buf->recycled,
                          cl->buf->in_file,
                          cl->buf->start,
                          cl->buf->pos,
                          cl->buf->last,
                          cl->buf->file,
                          cl->buf->file_pos,
                          cl->buf->file_last);

            ngx_debug_point();
            return NGX_ERROR;
        }

        if (ngx_buf_size(cl->buf) < 0) {
            ngx_log_error(NGX_LOG_ALERT, c->log, 0,
                          "negative size buf in writer "
                          "t:%d r:%d f:%d %p %p-%p %p %O-%O",
                          cl->buf->temporary,
                          cl->buf->recycled,
                          cl->buf->in_file,
                          cl->buf->start,
                          cl->buf->pos,
                          cl->buf->last,
                          cl->buf->file,
                          cl->buf->file_pos,
                          cl->buf->file_last);

            ngx_debug_point();
            return NGX_ERROR;
        }

        size += ngx_buf_size(cl->buf);

        if (cl->buf->flush || cl->buf->recycled) {
            flush = 1;
        }

        if (cl->buf->sync) {
            sync = 1;
        }

        if (cl->buf->last_buf) {
            last = 1;
        }
    }

    *ll = NULL;

    ngx_log_debug3(NGX_LOG_DEBUG_STREAM, c->log, 0,
                   "stream write filter: l:%ui f:%ui s:%O", last, flush, size);

    if (size == 0
        && !(c->buffered & NGX_LOWLEVEL_BUFFERED)
        && !(last && c->need_last_buf)
        && !(c->type == SOCK_DGRAM && flush))
    {
        if (last || flush || sync) {
            for (cl = *out; cl; /* void */) {
                ln = cl;
                cl = cl->next;
                ngx_free_chain(c->pool, ln);
            }

            *out = NULL;
            c->buffered &= ~NGX_STREAM_WRITE_BUFFERED;

            return NGX_OK;
        }

        ngx_log_error(NGX_LOG_ALERT, c->log, 0,
                      "the stream output chain is empty");

        ngx_debug_point();

        return NGX_ERROR;
    }

    chain = c->send_chain(c, *out, 0);

    ngx_log_debug1(NGX_LOG_DEBUG_STREAM, c->log, 0,
                   "stream write filter %p", chain);

    if (chain == NGX_CHAIN_ERROR) {
        c->error = 1;
        return NGX_ERROR;
    }

    for (cl = *out; cl && cl != chain; /* void */) {
        ln = cl;
        cl = cl->next;
        ngx_free_chain(c->pool, ln);
    }

    *out = chain;

    if (chain) {
        if (c->shared) {
            ngx_log_error(NGX_LOG_ALERT, c->log, 0,
                          "shared connection is busy");
            return NGX_ERROR;
        }

        c->buffered |= NGX_STREAM_WRITE_BUFFERED;
        return NGX_AGAIN;
    }

    c->buffered &= ~NGX_STREAM_WRITE_BUFFERED;

    if (c->buffered & NGX_LOWLEVEL_BUFFERED) {
        return NGX_AGAIN;
    }

    return NGX_OK;
}


static ngx_int_t
ngx_stream_write_filter_init(ngx_conf_t *cf)
{
    ngx_stream_top_filter = ngx_stream_write_filter;

    return NGX_OK;
}