Mercurial > hg > nginx-quic
view src/http/modules/ngx_http_gunzip_filter_module.c @ 7977:7731c710796f
Memcached: protect from too long responses.
If a memcached response was followed by a correct trailer, and then
the NUL character followed by some extra data - this was accepted by
the trailer checking code. This in turn resulted in ctx->rest underflow
and caused negative size buffer on the next reading from the upstream,
followed by the "negative size buf in writer" alert.
Fix is to always check for too long responses, so a correct trailer cannot
be followed by extra data.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 06 Jul 2020 18:36:17 +0300 |
parents | 973fded4f461 |
children |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Maxim Dounin * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> #include <zlib.h> typedef struct { ngx_flag_t enable; ngx_bufs_t bufs; } ngx_http_gunzip_conf_t; typedef struct { ngx_chain_t *in; ngx_chain_t *free; ngx_chain_t *busy; ngx_chain_t *out; ngx_chain_t **last_out; ngx_buf_t *in_buf; ngx_buf_t *out_buf; ngx_int_t bufs; unsigned started:1; unsigned flush:4; unsigned redo:1; unsigned done:1; unsigned nomem:1; z_stream zstream; ngx_http_request_t *request; } ngx_http_gunzip_ctx_t; static ngx_int_t ngx_http_gunzip_filter_inflate_start(ngx_http_request_t *r, ngx_http_gunzip_ctx_t *ctx); static ngx_int_t ngx_http_gunzip_filter_add_data(ngx_http_request_t *r, ngx_http_gunzip_ctx_t *ctx); static ngx_int_t ngx_http_gunzip_filter_get_buf(ngx_http_request_t *r, ngx_http_gunzip_ctx_t *ctx); static ngx_int_t ngx_http_gunzip_filter_inflate(ngx_http_request_t *r, ngx_http_gunzip_ctx_t *ctx); static ngx_int_t ngx_http_gunzip_filter_inflate_end(ngx_http_request_t *r, ngx_http_gunzip_ctx_t *ctx); static void *ngx_http_gunzip_filter_alloc(void *opaque, u_int items, u_int size); static void ngx_http_gunzip_filter_free(void *opaque, void *address); static ngx_int_t ngx_http_gunzip_filter_init(ngx_conf_t *cf); static void *ngx_http_gunzip_create_conf(ngx_conf_t *cf); static char *ngx_http_gunzip_merge_conf(ngx_conf_t *cf, void *parent, void *child); static ngx_command_t ngx_http_gunzip_filter_commands[] = { { ngx_string("gunzip"), 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_gunzip_conf_t, enable), NULL }, { ngx_string("gunzip_buffers"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2, ngx_conf_set_bufs_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_gunzip_conf_t, bufs), NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_gunzip_filter_module_ctx = { NULL, /* preconfiguration */ ngx_http_gunzip_filter_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_gunzip_create_conf, /* create location configuration */ ngx_http_gunzip_merge_conf /* merge location configuration */ }; ngx_module_t ngx_http_gunzip_filter_module = { NGX_MODULE_V1, &ngx_http_gunzip_filter_module_ctx, /* module context */ ngx_http_gunzip_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_gunzip_header_filter(ngx_http_request_t *r) { ngx_http_gunzip_ctx_t *ctx; ngx_http_gunzip_conf_t *conf; conf = ngx_http_get_module_loc_conf(r, ngx_http_gunzip_filter_module); /* TODO support multiple content-codings */ /* TODO always gunzip - due to configuration or module request */ /* TODO ignore content encoding? */ if (!conf->enable || r->headers_out.content_encoding == NULL || r->headers_out.content_encoding->value.len != 4 || ngx_strncasecmp(r->headers_out.content_encoding->value.data, (u_char *) "gzip", 4) != 0) { return ngx_http_next_header_filter(r); } r->gzip_vary = 1; if (!r->gzip_tested) { if (ngx_http_gzip_ok(r) == NGX_OK) { return ngx_http_next_header_filter(r); } } else if (r->gzip_ok) { return ngx_http_next_header_filter(r); } ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_gunzip_ctx_t)); if (ctx == NULL) { return NGX_ERROR; } ngx_http_set_ctx(r, ctx, ngx_http_gunzip_filter_module); ctx->request = r; r->filter_need_in_memory = 1; r->headers_out.content_encoding->hash = 0; r->headers_out.content_encoding = NULL; ngx_http_clear_content_length(r); ngx_http_clear_accept_ranges(r); ngx_http_weak_etag(r); return ngx_http_next_header_filter(r); } static ngx_int_t ngx_http_gunzip_body_filter(ngx_http_request_t *r, ngx_chain_t *in) { int rc; ngx_uint_t flush; ngx_chain_t *cl; ngx_http_gunzip_ctx_t *ctx; ctx = ngx_http_get_module_ctx(r, ngx_http_gunzip_filter_module); if (ctx == NULL || ctx->done) { return ngx_http_next_body_filter(r, in); } ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http gunzip filter"); if (!ctx->started) { if (ngx_http_gunzip_filter_inflate_start(r, ctx) != NGX_OK) { goto failed; } } if (in) { if (ngx_chain_add_copy(r->pool, &ctx->in, in) != NGX_OK) { goto failed; } } if (ctx->nomem) { /* flush busy buffers */ if (ngx_http_next_body_filter(r, NULL) == NGX_ERROR) { goto failed; } cl = NULL; ngx_chain_update_chains(r->pool, &ctx->free, &ctx->busy, &cl, (ngx_buf_tag_t) &ngx_http_gunzip_filter_module); ctx->nomem = 0; flush = 0; } else { flush = ctx->busy ? 1 : 0; } for ( ;; ) { /* cycle while we can write to a client */ for ( ;; ) { /* cycle while there is data to feed zlib and ... */ rc = ngx_http_gunzip_filter_add_data(r, ctx); if (rc == NGX_DECLINED) { break; } if (rc == NGX_AGAIN) { continue; } /* ... there are buffers to write zlib output */ rc = ngx_http_gunzip_filter_get_buf(r, ctx); if (rc == NGX_DECLINED) { break; } if (rc == NGX_ERROR) { goto failed; } rc = ngx_http_gunzip_filter_inflate(r, ctx); if (rc == NGX_OK) { break; } if (rc == NGX_ERROR) { goto failed; } /* rc == NGX_AGAIN */ } if (ctx->out == NULL && !flush) { return ctx->busy ? NGX_AGAIN : NGX_OK; } rc = ngx_http_next_body_filter(r, ctx->out); if (rc == NGX_ERROR) { goto failed; } ngx_chain_update_chains(r->pool, &ctx->free, &ctx->busy, &ctx->out, (ngx_buf_tag_t) &ngx_http_gunzip_filter_module); ctx->last_out = &ctx->out; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "gunzip out: %p", ctx->out); ctx->nomem = 0; flush = 0; if (ctx->done) { return rc; } } /* unreachable */ failed: ctx->done = 1; return NGX_ERROR; } static ngx_int_t ngx_http_gunzip_filter_inflate_start(ngx_http_request_t *r, ngx_http_gunzip_ctx_t *ctx) { int rc; ctx->zstream.next_in = Z_NULL; ctx->zstream.avail_in = 0; ctx->zstream.zalloc = ngx_http_gunzip_filter_alloc; ctx->zstream.zfree = ngx_http_gunzip_filter_free; ctx->zstream.opaque = ctx; /* windowBits +16 to decode gzip, zlib 1.2.0.4+ */ rc = inflateInit2(&ctx->zstream, MAX_WBITS + 16); if (rc != Z_OK) { ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0, "inflateInit2() failed: %d", rc); return NGX_ERROR; } ctx->started = 1; ctx->last_out = &ctx->out; ctx->flush = Z_NO_FLUSH; return NGX_OK; } static ngx_int_t ngx_http_gunzip_filter_add_data(ngx_http_request_t *r, ngx_http_gunzip_ctx_t *ctx) { if (ctx->zstream.avail_in || ctx->flush != Z_NO_FLUSH || ctx->redo) { return NGX_OK; } ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "gunzip in: %p", ctx->in); if (ctx->in == NULL) { return NGX_DECLINED; } ctx->in_buf = ctx->in->buf; ctx->in = ctx->in->next; ctx->zstream.next_in = ctx->in_buf->pos; ctx->zstream.avail_in = ctx->in_buf->last - ctx->in_buf->pos; ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "gunzip in_buf:%p ni:%p ai:%ud", ctx->in_buf, ctx->zstream.next_in, ctx->zstream.avail_in); if (ctx->in_buf->last_buf || ctx->in_buf->last_in_chain) { ctx->flush = Z_FINISH; } else if (ctx->in_buf->flush) { ctx->flush = Z_SYNC_FLUSH; } else if (ctx->zstream.avail_in == 0) { /* ctx->flush == Z_NO_FLUSH */ return NGX_AGAIN; } return NGX_OK; } static ngx_int_t ngx_http_gunzip_filter_get_buf(ngx_http_request_t *r, ngx_http_gunzip_ctx_t *ctx) { ngx_http_gunzip_conf_t *conf; if (ctx->zstream.avail_out) { return NGX_OK; } conf = ngx_http_get_module_loc_conf(r, ngx_http_gunzip_filter_module); if (ctx->free) { ctx->out_buf = ctx->free->buf; ctx->free = ctx->free->next; ctx->out_buf->flush = 0; } else if (ctx->bufs < conf->bufs.num) { ctx->out_buf = ngx_create_temp_buf(r->pool, conf->bufs.size); if (ctx->out_buf == NULL) { return NGX_ERROR; } ctx->out_buf->tag = (ngx_buf_tag_t) &ngx_http_gunzip_filter_module; ctx->out_buf->recycled = 1; ctx->bufs++; } else { ctx->nomem = 1; return NGX_DECLINED; } ctx->zstream.next_out = ctx->out_buf->pos; ctx->zstream.avail_out = conf->bufs.size; return NGX_OK; } static ngx_int_t ngx_http_gunzip_filter_inflate(ngx_http_request_t *r, ngx_http_gunzip_ctx_t *ctx) { int rc; ngx_buf_t *b; ngx_chain_t *cl; ngx_log_debug6(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "inflate in: ni:%p no:%p ai:%ud ao:%ud fl:%d redo:%d", ctx->zstream.next_in, ctx->zstream.next_out, ctx->zstream.avail_in, ctx->zstream.avail_out, ctx->flush, ctx->redo); rc = inflate(&ctx->zstream, ctx->flush); if (rc != Z_OK && rc != Z_STREAM_END && rc != Z_BUF_ERROR) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "inflate() failed: %d, %d", ctx->flush, rc); return NGX_ERROR; } ngx_log_debug5(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "inflate out: ni:%p no:%p ai:%ud ao:%ud rc:%d", ctx->zstream.next_in, ctx->zstream.next_out, ctx->zstream.avail_in, ctx->zstream.avail_out, rc); ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "gunzip in_buf:%p pos:%p", ctx->in_buf, ctx->in_buf->pos); if (ctx->zstream.next_in) { ctx->in_buf->pos = ctx->zstream.next_in; if (ctx->zstream.avail_in == 0) { ctx->zstream.next_in = NULL; } } ctx->out_buf->last = ctx->zstream.next_out; if (ctx->zstream.avail_out == 0) { /* zlib wants to output some more data */ cl = ngx_alloc_chain_link(r->pool); if (cl == NULL) { return NGX_ERROR; } cl->buf = ctx->out_buf; cl->next = NULL; *ctx->last_out = cl; ctx->last_out = &cl->next; ctx->redo = 1; return NGX_AGAIN; } ctx->redo = 0; if (ctx->flush == Z_SYNC_FLUSH) { ctx->flush = Z_NO_FLUSH; cl = ngx_alloc_chain_link(r->pool); if (cl == NULL) { return NGX_ERROR; } b = ctx->out_buf; if (ngx_buf_size(b) == 0) { b = ngx_calloc_buf(ctx->request->pool); if (b == NULL) { return NGX_ERROR; } } else { ctx->zstream.avail_out = 0; } b->flush = 1; cl->buf = b; cl->next = NULL; *ctx->last_out = cl; ctx->last_out = &cl->next; return NGX_OK; } if (ctx->flush == Z_FINISH && ctx->zstream.avail_in == 0) { if (rc != Z_STREAM_END) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "inflate() returned %d on response end", rc); return NGX_ERROR; } if (ngx_http_gunzip_filter_inflate_end(r, ctx) != NGX_OK) { return NGX_ERROR; } return NGX_OK; } if (rc == Z_STREAM_END && ctx->zstream.avail_in > 0) { rc = inflateReset(&ctx->zstream); if (rc != Z_OK) { ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0, "inflateReset() failed: %d", rc); return NGX_ERROR; } ctx->redo = 1; return NGX_AGAIN; } if (ctx->in == NULL) { b = ctx->out_buf; if (ngx_buf_size(b) == 0) { return NGX_OK; } cl = ngx_alloc_chain_link(r->pool); if (cl == NULL) { return NGX_ERROR; } ctx->zstream.avail_out = 0; cl->buf = b; cl->next = NULL; *ctx->last_out = cl; ctx->last_out = &cl->next; return NGX_OK; } return NGX_AGAIN; } static ngx_int_t ngx_http_gunzip_filter_inflate_end(ngx_http_request_t *r, ngx_http_gunzip_ctx_t *ctx) { int rc; ngx_buf_t *b; ngx_chain_t *cl; ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "gunzip inflate end"); rc = inflateEnd(&ctx->zstream); if (rc != Z_OK) { ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0, "inflateEnd() failed: %d", rc); return NGX_ERROR; } b = ctx->out_buf; if (ngx_buf_size(b) == 0) { b = ngx_calloc_buf(ctx->request->pool); if (b == NULL) { return NGX_ERROR; } } cl = ngx_alloc_chain_link(r->pool); if (cl == NULL) { return NGX_ERROR; } cl->buf = b; cl->next = NULL; *ctx->last_out = cl; ctx->last_out = &cl->next; b->last_buf = (r == r->main) ? 1 : 0; b->last_in_chain = 1; b->sync = 1; ctx->done = 1; return NGX_OK; } static void * ngx_http_gunzip_filter_alloc(void *opaque, u_int items, u_int size) { ngx_http_gunzip_ctx_t *ctx = opaque; ngx_log_debug2(NGX_LOG_DEBUG_HTTP, ctx->request->connection->log, 0, "gunzip alloc: n:%ud s:%ud", items, size); return ngx_palloc(ctx->request->pool, items * size); } static void ngx_http_gunzip_filter_free(void *opaque, void *address) { #if 0 ngx_http_gunzip_ctx_t *ctx = opaque; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, ctx->request->connection->log, 0, "gunzip free: %p", address); #endif } static void * ngx_http_gunzip_create_conf(ngx_conf_t *cf) { ngx_http_gunzip_conf_t *conf; conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_gunzip_conf_t)); if (conf == NULL) { return NULL; } /* * set by ngx_pcalloc(): * * conf->bufs.num = 0; */ conf->enable = NGX_CONF_UNSET; return conf; } static char * ngx_http_gunzip_merge_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_gunzip_conf_t *prev = parent; ngx_http_gunzip_conf_t *conf = child; ngx_conf_merge_value(conf->enable, prev->enable, 0); ngx_conf_merge_bufs_value(conf->bufs, prev->bufs, (128 * 1024) / ngx_pagesize, ngx_pagesize); return NGX_CONF_OK; } static ngx_int_t ngx_http_gunzip_filter_init(ngx_conf_t *cf) { ngx_http_next_header_filter = ngx_http_top_header_filter; ngx_http_top_header_filter = ngx_http_gunzip_header_filter; ngx_http_next_body_filter = ngx_http_top_body_filter; ngx_http_top_body_filter = ngx_http_gunzip_body_filter; return NGX_OK; }