e0b378d22b
## Issue When we use GCC-12 later or clang 9.0 later to build with `-D_FORTIFY_SOURCE=3`, we can see the following buffer overflow: ``` === REDIS BUG REPORT START: Cut & paste starting from here === 6263:M 06 Apr 2023 08:59:12.915 # Redis 255.255.255 crashed by signal: 6, si_code: -6 6263:M 06 Apr 2023 08:59:12.915 # Crashed running the instruction at: 0x7f03d59efa7c ------ STACK TRACE ------ EIP: /lib/x86_64-linux-gnu/libc.so.6(pthread_kill+0x12c)[0x7f03d59efa7c] Backtrace: /lib/x86_64-linux-gnu/libc.so.6(+0x42520)[0x7f03d599b520] /lib/x86_64-linux-gnu/libc.so.6(pthread_kill+0x12c)[0x7f03d59efa7c] /lib/x86_64-linux-gnu/libc.so.6(raise+0x16)[0x7f03d599b476] /lib/x86_64-linux-gnu/libc.so.6(abort+0xd3)[0x7f03d59817f3] /lib/x86_64-linux-gnu/libc.so.6(+0x896f6)[0x7f03d59e26f6] /lib/x86_64-linux-gnu/libc.so.6(__fortify_fail+0x2a)[0x7f03d5a8f76a] /lib/x86_64-linux-gnu/libc.so.6(+0x1350c6)[0x7f03d5a8e0c6] src/redis-server 127.0.0.1:25111(+0xd5e80)[0x557cddd3be80] src/redis-server 127.0.0.1:25111(feedReplicationBufferWithObject+0x78)[0x557cddd3c768] src/redis-server 127.0.0.1:25111(replicationFeedSlaves+0x1a4)[0x557cddd3cbc4] src/redis-server 127.0.0.1:25111(+0x8721a)[0x557cddced21a] src/redis-server 127.0.0.1:25111(call+0x47a)[0x557cddcf38ea] src/redis-server 127.0.0.1:25111(processCommand+0xbf4)[0x557cddcf4aa4] src/redis-server 127.0.0.1:25111(processInputBuffer+0xe6)[0x557cddd22216] src/redis-server 127.0.0.1:25111(readQueryFromClient+0x3a8)[0x557cddd22898] src/redis-server 127.0.0.1:25111(+0x1b9134)[0x557cdde1f134] src/redis-server 127.0.0.1:25111(aeMain+0x119)[0x557cddce5349] src/redis-server 127.0.0.1:25111(main+0x466)[0x557cddcd6716] /lib/x86_64-linux-gnu/libc.so.6(+0x29d90)[0x7f03d5982d90] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80)[0x7f03d5982e40] src/redis-server 127.0.0.1:25111(_start+0x25)[0x557cddcd7025] ``` The main reason is that when FORTIFY_SOURCE is enabled, GCC or clang will enhance some common functions, such as `strcpy`, `memcpy`, `fgets`, etc, so that they can detect buffer overflow errors and stop program execution, thus improving the safety of the program. We use `zmalloc_usable_size()` everywhere to use memory blocks, but that is an abuse since the malloc_usable_size() isn't meant for this kind of use, it is for diagnostics only. That is also why the behavior is flaky when built with _FORTIFY_SOURCE, the compiler can sense that we reach outside the allocated block and SIGABRT. ### Solution If we need to use the additional memory we got, we need to use a dummy realloc with `alloc_size` attribute and no inlining, (see `extend_to_usable`) to let the compiler see the large of memory we need to use. This can either be an implicit call inside `z*usable` that returns the size, so that the caller doesn't have any other worry, or it can be a normal zmalloc call which means that if the caller wants to use zmalloc_usable_size it must also use extend_to_usable. ### Changes This PR does the following: 1) rename the current z[try]malloc_usable family to z[try]malloc_internal and don't expose them to users outside zmalloc.c, 2) expose a new set of `z[*]_usable` family that use z[*]_internal and `extend_to_usable()` implicitly, the caller gets the size of the allocation and it is safe to use. 3) go over all the users of `zmalloc_usable_size` and convert them to use the `z[*]_usable` family if possible. 4) in the places where the caller can't use `z[*]_usable` and store the real size, and must still rely on zmalloc_usable_size, we still make sure that the allocation used `z[*]_usable` (which has a call to `extend_to_usable()`) and ignores the returning size, this way a later call to `zmalloc_usable_size` is still safe. [4] was done for module.c and listpack.c, all the others places (sds, reply proto list, replication backlog, client->buf) are using [3]. Co-authored-by: Oran Agra <oran@redislabs.com>
50 lines
2.4 KiB
C
50 lines
2.4 KiB
C
/* Listpack -- A lists of strings serialization format
|
|
* https://github.com/antirez/listpack
|
|
*
|
|
* Copyright (c) 2017, Salvatore Sanfilippo <antirez at gmail dot com>
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions are met:
|
|
*
|
|
* * Redistributions of source code must retain the above copyright notice,
|
|
* this list of conditions and the following disclaimer.
|
|
* * Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* * Neither the name of Redis nor the names of its contributors may be used
|
|
* to endorse or promote products derived from this software without
|
|
* specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
|
|
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
|
|
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
* POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
/* Allocator selection.
|
|
*
|
|
* This file is used in order to change the Rax allocator at compile time.
|
|
* Just define the following defines to what you want to use. Also add
|
|
* the include of your alternate allocator if needed (not needed in order
|
|
* to use the default libc allocator). */
|
|
|
|
#ifndef LISTPACK_ALLOC_H
|
|
#define LISTPACK_ALLOC_H
|
|
#include "zmalloc.h"
|
|
/* We use zmalloc_usable/zrealloc_usable instead of zmalloc/zrealloc
|
|
* to ensure the safe invocation of 'zmalloc_usable_size().
|
|
* See comment in zmalloc_usable_size(). */
|
|
#define lp_malloc(sz) zmalloc_usable(sz,NULL)
|
|
#define lp_realloc(ptr,sz) zrealloc_usable(ptr,sz,NULL)
|
|
#define lp_free zfree
|
|
#define lp_malloc_size zmalloc_usable_size
|
|
#endif
|