Mercurial > hg > nginx
view src/http/v2/ngx_http_v2_table.c @ 7674:7731c710796f
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 | 87e9e4aabf1b |
children |
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/* * Copyright (C) Nginx, Inc. * Copyright (C) Valentin V. Bartenev */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> #define NGX_HTTP_V2_TABLE_SIZE 4096 static ngx_int_t ngx_http_v2_table_account(ngx_http_v2_connection_t *h2c, size_t size); static ngx_http_v2_header_t ngx_http_v2_static_table[] = { { ngx_string(":authority"), ngx_string("") }, { ngx_string(":method"), ngx_string("GET") }, { ngx_string(":method"), ngx_string("POST") }, { ngx_string(":path"), ngx_string("/") }, { ngx_string(":path"), ngx_string("/index.html") }, { ngx_string(":scheme"), ngx_string("http") }, { ngx_string(":scheme"), ngx_string("https") }, { ngx_string(":status"), ngx_string("200") }, { ngx_string(":status"), ngx_string("204") }, { ngx_string(":status"), ngx_string("206") }, { ngx_string(":status"), ngx_string("304") }, { ngx_string(":status"), ngx_string("400") }, { ngx_string(":status"), ngx_string("404") }, { ngx_string(":status"), ngx_string("500") }, { ngx_string("accept-charset"), ngx_string("") }, { ngx_string("accept-encoding"), ngx_string("gzip, deflate") }, { ngx_string("accept-language"), ngx_string("") }, { ngx_string("accept-ranges"), ngx_string("") }, { ngx_string("accept"), ngx_string("") }, { ngx_string("access-control-allow-origin"), ngx_string("") }, { ngx_string("age"), ngx_string("") }, { ngx_string("allow"), ngx_string("") }, { ngx_string("authorization"), ngx_string("") }, { ngx_string("cache-control"), ngx_string("") }, { ngx_string("content-disposition"), ngx_string("") }, { ngx_string("content-encoding"), ngx_string("") }, { ngx_string("content-language"), ngx_string("") }, { ngx_string("content-length"), ngx_string("") }, { ngx_string("content-location"), ngx_string("") }, { ngx_string("content-range"), ngx_string("") }, { ngx_string("content-type"), ngx_string("") }, { ngx_string("cookie"), ngx_string("") }, { ngx_string("date"), ngx_string("") }, { ngx_string("etag"), ngx_string("") }, { ngx_string("expect"), ngx_string("") }, { ngx_string("expires"), ngx_string("") }, { ngx_string("from"), ngx_string("") }, { ngx_string("host"), ngx_string("") }, { ngx_string("if-match"), ngx_string("") }, { ngx_string("if-modified-since"), ngx_string("") }, { ngx_string("if-none-match"), ngx_string("") }, { ngx_string("if-range"), ngx_string("") }, { ngx_string("if-unmodified-since"), ngx_string("") }, { ngx_string("last-modified"), ngx_string("") }, { ngx_string("link"), ngx_string("") }, { ngx_string("location"), ngx_string("") }, { ngx_string("max-forwards"), ngx_string("") }, { ngx_string("proxy-authenticate"), ngx_string("") }, { ngx_string("proxy-authorization"), ngx_string("") }, { ngx_string("range"), ngx_string("") }, { ngx_string("referer"), ngx_string("") }, { ngx_string("refresh"), ngx_string("") }, { ngx_string("retry-after"), ngx_string("") }, { ngx_string("server"), ngx_string("") }, { ngx_string("set-cookie"), ngx_string("") }, { ngx_string("strict-transport-security"), ngx_string("") }, { ngx_string("transfer-encoding"), ngx_string("") }, { ngx_string("user-agent"), ngx_string("") }, { ngx_string("vary"), ngx_string("") }, { ngx_string("via"), ngx_string("") }, { ngx_string("www-authenticate"), ngx_string("") }, }; #define NGX_HTTP_V2_STATIC_TABLE_ENTRIES \ (sizeof(ngx_http_v2_static_table) \ / sizeof(ngx_http_v2_header_t)) ngx_str_t * ngx_http_v2_get_static_name(ngx_uint_t index) { return &ngx_http_v2_static_table[index - 1].name; } ngx_str_t * ngx_http_v2_get_static_value(ngx_uint_t index) { return &ngx_http_v2_static_table[index - 1].value; } ngx_int_t ngx_http_v2_get_indexed_header(ngx_http_v2_connection_t *h2c, ngx_uint_t index, ngx_uint_t name_only) { u_char *p; size_t rest; ngx_http_v2_header_t *entry; if (index == 0) { ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0, "client sent invalid hpack table index 0"); return NGX_ERROR; } ngx_log_debug2(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, "http2 get indexed %s: %ui", name_only ? "name" : "header", index); index--; if (index < NGX_HTTP_V2_STATIC_TABLE_ENTRIES) { h2c->state.header = ngx_http_v2_static_table[index]; return NGX_OK; } index -= NGX_HTTP_V2_STATIC_TABLE_ENTRIES; if (index < h2c->hpack.added - h2c->hpack.deleted) { index = (h2c->hpack.added - index - 1) % h2c->hpack.allocated; entry = h2c->hpack.entries[index]; p = ngx_pnalloc(h2c->state.pool, entry->name.len + 1); if (p == NULL) { return NGX_ERROR; } h2c->state.header.name.len = entry->name.len; h2c->state.header.name.data = p; rest = h2c->hpack.storage + NGX_HTTP_V2_TABLE_SIZE - entry->name.data; if (entry->name.len > rest) { p = ngx_cpymem(p, entry->name.data, rest); p = ngx_cpymem(p, h2c->hpack.storage, entry->name.len - rest); } else { p = ngx_cpymem(p, entry->name.data, entry->name.len); } *p = '\0'; if (name_only) { return NGX_OK; } p = ngx_pnalloc(h2c->state.pool, entry->value.len + 1); if (p == NULL) { return NGX_ERROR; } h2c->state.header.value.len = entry->value.len; h2c->state.header.value.data = p; rest = h2c->hpack.storage + NGX_HTTP_V2_TABLE_SIZE - entry->value.data; if (entry->value.len > rest) { p = ngx_cpymem(p, entry->value.data, rest); p = ngx_cpymem(p, h2c->hpack.storage, entry->value.len - rest); } else { p = ngx_cpymem(p, entry->value.data, entry->value.len); } *p = '\0'; return NGX_OK; } ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0, "client sent out of bound hpack table index: %ui", index); return NGX_ERROR; } ngx_int_t ngx_http_v2_add_header(ngx_http_v2_connection_t *h2c, ngx_http_v2_header_t *header) { size_t avail; ngx_uint_t index; ngx_http_v2_header_t *entry, **entries; ngx_log_debug2(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, "http2 table add: \"%V: %V\"", &header->name, &header->value); if (h2c->hpack.entries == NULL) { h2c->hpack.allocated = 64; h2c->hpack.size = NGX_HTTP_V2_TABLE_SIZE; h2c->hpack.free = NGX_HTTP_V2_TABLE_SIZE; h2c->hpack.entries = ngx_palloc(h2c->connection->pool, sizeof(ngx_http_v2_header_t *) * h2c->hpack.allocated); if (h2c->hpack.entries == NULL) { return NGX_ERROR; } h2c->hpack.storage = ngx_palloc(h2c->connection->pool, h2c->hpack.free); if (h2c->hpack.storage == NULL) { return NGX_ERROR; } h2c->hpack.pos = h2c->hpack.storage; } if (ngx_http_v2_table_account(h2c, header->name.len + header->value.len) != NGX_OK) { return NGX_OK; } if (h2c->hpack.reused == h2c->hpack.deleted) { entry = ngx_palloc(h2c->connection->pool, sizeof(ngx_http_v2_header_t)); if (entry == NULL) { return NGX_ERROR; } } else { entry = h2c->hpack.entries[h2c->hpack.reused++ % h2c->hpack.allocated]; } avail = h2c->hpack.storage + NGX_HTTP_V2_TABLE_SIZE - h2c->hpack.pos; entry->name.len = header->name.len; entry->name.data = h2c->hpack.pos; if (avail >= header->name.len) { h2c->hpack.pos = ngx_cpymem(h2c->hpack.pos, header->name.data, header->name.len); } else { ngx_memcpy(h2c->hpack.pos, header->name.data, avail); h2c->hpack.pos = ngx_cpymem(h2c->hpack.storage, header->name.data + avail, header->name.len - avail); avail = NGX_HTTP_V2_TABLE_SIZE; } avail -= header->name.len; entry->value.len = header->value.len; entry->value.data = h2c->hpack.pos; if (avail >= header->value.len) { h2c->hpack.pos = ngx_cpymem(h2c->hpack.pos, header->value.data, header->value.len); } else { ngx_memcpy(h2c->hpack.pos, header->value.data, avail); h2c->hpack.pos = ngx_cpymem(h2c->hpack.storage, header->value.data + avail, header->value.len - avail); } if (h2c->hpack.allocated == h2c->hpack.added - h2c->hpack.deleted) { entries = ngx_palloc(h2c->connection->pool, sizeof(ngx_http_v2_header_t *) * (h2c->hpack.allocated + 64)); if (entries == NULL) { return NGX_ERROR; } index = h2c->hpack.deleted % h2c->hpack.allocated; ngx_memcpy(entries, &h2c->hpack.entries[index], (h2c->hpack.allocated - index) * sizeof(ngx_http_v2_header_t *)); ngx_memcpy(&entries[h2c->hpack.allocated - index], h2c->hpack.entries, index * sizeof(ngx_http_v2_header_t *)); (void) ngx_pfree(h2c->connection->pool, h2c->hpack.entries); h2c->hpack.entries = entries; h2c->hpack.added = h2c->hpack.allocated; h2c->hpack.deleted = 0; h2c->hpack.reused = 0; h2c->hpack.allocated += 64; } h2c->hpack.entries[h2c->hpack.added++ % h2c->hpack.allocated] = entry; return NGX_OK; } static ngx_int_t ngx_http_v2_table_account(ngx_http_v2_connection_t *h2c, size_t size) { ngx_http_v2_header_t *entry; size += 32; ngx_log_debug2(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, "http2 table account: %uz free:%uz", size, h2c->hpack.free); if (size <= h2c->hpack.free) { h2c->hpack.free -= size; return NGX_OK; } if (size > h2c->hpack.size) { h2c->hpack.deleted = h2c->hpack.added; h2c->hpack.free = h2c->hpack.size; return NGX_DECLINED; } do { entry = h2c->hpack.entries[h2c->hpack.deleted++ % h2c->hpack.allocated]; h2c->hpack.free += 32 + entry->name.len + entry->value.len; } while (size > h2c->hpack.free); h2c->hpack.free -= size; return NGX_OK; } ngx_int_t ngx_http_v2_table_size(ngx_http_v2_connection_t *h2c, size_t size) { ssize_t needed; ngx_http_v2_header_t *entry; if (size > NGX_HTTP_V2_TABLE_SIZE) { ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0, "client sent invalid table size update: %uz", size); return NGX_ERROR; } ngx_log_debug2(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, "http2 new hpack table size: %uz was:%uz", size, h2c->hpack.size); needed = h2c->hpack.size - size; while (needed > (ssize_t) h2c->hpack.free) { entry = h2c->hpack.entries[h2c->hpack.deleted++ % h2c->hpack.allocated]; h2c->hpack.free += 32 + entry->name.len + entry->value.len; } h2c->hpack.size = size; h2c->hpack.free -= needed; return NGX_OK; }