From patchwork Wed May 22 11:59:07 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baokun Li X-Patchwork-Id: 13670393 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4F9A3537E9; Wed, 22 May 2024 04:06:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716350762; cv=none; b=Rzryq4IZj4wXY3Q7S0DODCbpQPz93ydX8tP8qC8ZVsS6yYuc1lMZhHjf5UP7rWkcasvVZ+jEfBbaBWtXNaOsOeejf1H4zsZip0KBR3Vsu/0anRNtJ5FKK6/4rRaiUxPFkd9By0moeMh9emO61BLYXMx/wSgjreQ27bKmH8jJIW8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716350762; c=relaxed/simple; bh=6XI1XN34NW4rt/zFdE8AebS1urwUF5nF67y/z3rb7U8=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=WX+ngq8I5RRRWVZJvQTdogDgHFAoM2mJouw5P7Eacvt3WyeoYYrckwJGBPUceZE19QMxIbUJJhiF7eYlwf1C1aOEix3YUNS3ZAOwl5x26LgQwftHdbXtQ3yOeoRXqNss/E0D8HgxpS5hvZHi5b4j2AYSVWJ5Gr8irhh3gFW5hQ4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.216]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4Vkd5650dFz4f3m76; Wed, 22 May 2024 12:05:46 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.112]) by mail.maildlp.com (Postfix) with ESMTP id 2DA7D1A0199; Wed, 22 May 2024 12:05:57 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP1 (Coremail) with SMTP id cCh0CgBHZQ4ib01ms1VYNQ--.24441S5; Wed, 22 May 2024 12:05:56 +0800 (CST) From: libaokun@huaweicloud.com To: netfs@lists.linux.dev, dhowells@redhat.com, jlayton@kernel.org Cc: hsiangkao@linux.alibaba.com, jefflexu@linux.alibaba.com, zhujia.zj@bytedance.com, linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, libaokun@huaweicloud.com, yangerkun@huawei.com, houtao1@huawei.com, yukuai3@huawei.com, wozizhi@huawei.com, Baokun Li Subject: [PATCH RESEND 1/5] netfs, fscache: export fscache_put_volume() and add fscache_try_get_volume() Date: Wed, 22 May 2024 19:59:07 +0800 Message-Id: <20240522115911.2403021-2-libaokun@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240522115911.2403021-1-libaokun@huaweicloud.com> References: <20240522115911.2403021-1-libaokun@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: cCh0CgBHZQ4ib01ms1VYNQ--.24441S5 X-Coremail-Antispam: 1UD129KBjvJXoWxGw17ur1rJw1kWw1rCr1rWFg_yoW5Cr1Dp3 srCrn7KF48Xw1xGw45Xw47Zrn3Z3yDKan7G3y8Gw15Cw4xJr15XF12yw15AF13A34UJrWI yF1Utryjgw1UZr7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUQmb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M280x2IEY4vEnII2IxkI6r1a6r45M2 8IrcIa0xkI8VA2jI8067AKxVWUGwA2048vs2IY020Ec7CjxVAFwI0_Gr0_Xr1l8cAvFVAK 0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4 x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l 84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I 8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AK xVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zV CS5cI20VAGYxC7M4IIrI8v6xkF7I0E8cxan2IY04v7M4kE6xkIj40Ew7xC0wCF04k20xvY 0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I 0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAI cVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcV CF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r4j6F4UMIIF0xvEx4A2jsIE c7CjxVAFwI0_Gr1j6F4UJbIYCTnIWIevJa73UjIFyTuYvjTRPfQMDUUUU X-CM-SenderInfo: 5olet0hnxqqx5xdzvxpfor3voofrz/ From: Baokun Li Export fscache_put_volume() and add fscache_try_get_volume() helper function to allow cachefiles to get/put fscache_volume via linux/fscache-cache.h. Signed-off-by: Baokun Li --- fs/netfs/fscache_volume.c | 14 ++++++++++++++ fs/netfs/internal.h | 2 -- include/linux/fscache-cache.h | 6 ++++++ 3 files changed, 20 insertions(+), 2 deletions(-) diff --git a/fs/netfs/fscache_volume.c b/fs/netfs/fscache_volume.c index cdf991bdd9de..cb75c07b5281 100644 --- a/fs/netfs/fscache_volume.c +++ b/fs/netfs/fscache_volume.c @@ -27,6 +27,19 @@ struct fscache_volume *fscache_get_volume(struct fscache_volume *volume, return volume; } +struct fscache_volume *fscache_try_get_volume(struct fscache_volume *volume, + enum fscache_volume_trace where) +{ + int ref; + + if (!__refcount_inc_not_zero(&volume->ref, &ref)) + return NULL; + + trace_fscache_volume(volume->debug_id, ref + 1, where); + return volume; +} +EXPORT_SYMBOL(fscache_try_get_volume); + static void fscache_see_volume(struct fscache_volume *volume, enum fscache_volume_trace where) { @@ -420,6 +433,7 @@ void fscache_put_volume(struct fscache_volume *volume, fscache_free_volume(volume); } } +EXPORT_SYMBOL(fscache_put_volume); /* * Relinquish a volume representation cookie. diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h index 95e281a8af78..2a071b8010fa 100644 --- a/fs/netfs/internal.h +++ b/fs/netfs/internal.h @@ -353,8 +353,6 @@ extern const struct seq_operations fscache_volumes_seq_ops; struct fscache_volume *fscache_get_volume(struct fscache_volume *volume, enum fscache_volume_trace where); -void fscache_put_volume(struct fscache_volume *volume, - enum fscache_volume_trace where); bool fscache_begin_volume_access(struct fscache_volume *volume, struct fscache_cookie *cookie, enum fscache_access_trace why); diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h index bdf7f3eddf0a..4c91a019972b 100644 --- a/include/linux/fscache-cache.h +++ b/include/linux/fscache-cache.h @@ -19,6 +19,7 @@ enum fscache_cache_trace; enum fscache_cookie_trace; enum fscache_access_trace; +enum fscache_volume_trace; enum fscache_cache_state { FSCACHE_CACHE_IS_NOT_PRESENT, /* No cache is present for this name */ @@ -97,6 +98,11 @@ extern void fscache_withdraw_cookie(struct fscache_cookie *cookie); extern void fscache_io_error(struct fscache_cache *cache); +extern struct fscache_volume * +fscache_try_get_volume(struct fscache_volume *volume, + enum fscache_volume_trace where); +extern void fscache_put_volume(struct fscache_volume *volume, + enum fscache_volume_trace where); extern void fscache_end_volume_access(struct fscache_volume *volume, struct fscache_cookie *cookie, enum fscache_access_trace why); From patchwork Wed May 22 11:59:08 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baokun Li X-Patchwork-Id: 13670394 Received: from dggsgout12.his.huawei.com (unknown [45.249.212.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C74D357CA2; Wed, 22 May 2024 04:06:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.56 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; 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Wed, 22 May 2024 12:05:48 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.112]) by mail.maildlp.com (Postfix) with ESMTP id C1BAE1A1537; Wed, 22 May 2024 12:05:57 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP1 (Coremail) with SMTP id cCh0CgBHZQ4ib01ms1VYNQ--.24441S6; Wed, 22 May 2024 12:05:57 +0800 (CST) From: libaokun@huaweicloud.com To: netfs@lists.linux.dev, dhowells@redhat.com, jlayton@kernel.org Cc: hsiangkao@linux.alibaba.com, jefflexu@linux.alibaba.com, zhujia.zj@bytedance.com, linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, libaokun@huaweicloud.com, yangerkun@huawei.com, houtao1@huawei.com, yukuai3@huawei.com, wozizhi@huawei.com, Baokun Li Subject: [PATCH RESEND 2/5] cachefiles: fix slab-use-after-free in fscache_withdraw_volume() Date: Wed, 22 May 2024 19:59:08 +0800 Message-Id: <20240522115911.2403021-3-libaokun@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240522115911.2403021-1-libaokun@huaweicloud.com> References: <20240522115911.2403021-1-libaokun@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: cCh0CgBHZQ4ib01ms1VYNQ--.24441S6 X-Coremail-Antispam: 1UD129KBjvJXoW3Wr1UXrW3Aw1DZr13ZF4Utwb_yoW7tFyxpa 9IvryxtrW8u3yUGw45Xw47Xr93X3s8Ja1kWw18Gr18Cw4rZr1YqF1jkw1rZFy3C3ykArZ2 k3WUKryUWw1jyr7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUQY14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2jI8I6cxK62vIxIIY0VWUZVW8XwA2048vs2IY02 0E87I2jVAFwI0_Jryl82xGYIkIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2 F7IY1VAKz4vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjx v20xvEc7CjxVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2 z280aVCY1x0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0V AKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1l Ox8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErc IFxwACI402YVCY1x02628vn2kIc2xKxwAKzVCY07xG64k0F24l42xK82IYc2Ij64vIr41l 4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67 AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8I cVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42xK8VAvwI 8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVW8JVWxJwCI42IY6I8E87Iv6xkF7I0E14v2 6r4UJVWxJrUvcSsGvfC2KfnxnUUI43ZEXa7sRiUDGUUUUUU== X-CM-SenderInfo: 5olet0hnxqqx5xdzvxpfor3voofrz/ From: Baokun Li We got the following issue in our fault injection stress test: ================================================================== BUG: KASAN: slab-use-after-free in fscache_withdraw_volume+0x2e1/0x370 Read of size 4 at addr ffff88810680be08 by task ondemand-04-dae/5798 CPU: 0 PID: 5798 Comm: ondemand-04-dae Not tainted 6.8.0-dirty #565 Call Trace: kasan_check_range+0xf6/0x1b0 fscache_withdraw_volume+0x2e1/0x370 cachefiles_withdraw_volume+0x31/0x50 cachefiles_withdraw_cache+0x3ad/0x900 cachefiles_put_unbind_pincount+0x1f6/0x250 cachefiles_daemon_release+0x13b/0x290 __fput+0x204/0xa00 task_work_run+0x139/0x230 Allocated by task 5820: __kmalloc+0x1df/0x4b0 fscache_alloc_volume+0x70/0x600 __fscache_acquire_volume+0x1c/0x610 erofs_fscache_register_volume+0x96/0x1a0 erofs_fscache_register_fs+0x49a/0x690 erofs_fc_fill_super+0x6c0/0xcc0 vfs_get_super+0xa9/0x140 vfs_get_tree+0x8e/0x300 do_new_mount+0x28c/0x580 [...] Freed by task 5820: kfree+0xf1/0x2c0 fscache_put_volume.part.0+0x5cb/0x9e0 erofs_fscache_unregister_fs+0x157/0x1b0 erofs_kill_sb+0xd9/0x1c0 deactivate_locked_super+0xa3/0x100 vfs_get_super+0x105/0x140 vfs_get_tree+0x8e/0x300 do_new_mount+0x28c/0x580 [...] ================================================================== Following is the process that triggers the issue: mount failed | daemon exit ------------------------------------------------------------ deactivate_locked_super cachefiles_daemon_release erofs_kill_sb erofs_fscache_unregister_fs fscache_relinquish_volume __fscache_relinquish_volume fscache_put_volume(fscache_volume, fscache_volume_put_relinquish) zero = __refcount_dec_and_test(&fscache_volume->ref, &ref); cachefiles_put_unbind_pincount cachefiles_daemon_unbind cachefiles_withdraw_cache cachefiles_withdraw_volumes list_del_init(&volume->cache_link) fscache_free_volume(fscache_volume) cache->ops->free_volume cachefiles_free_volume list_del_init(&cachefiles_volume->cache_link); kfree(fscache_volume) cachefiles_withdraw_volume fscache_withdraw_volume fscache_volume->n_accesses // fscache_volume UAF !!! The fscache_volume in cache->volumes must not have been freed yet, but its reference count may be 0. So use the new fscache_try_get_volume() helper function try to get its reference count. If the reference count of fscache_volume is 0, fscache_put_volume() is freeing it, so wait for it to be removed from cache->volumes. If its reference count is not 0, call cachefiles_withdraw_volume() with reference count protection to avoid the above issue. Fixes: fe2140e2f57f ("cachefiles: Implement volume support") Signed-off-by: Baokun Li --- fs/cachefiles/cache.c | 10 ++++++++++ include/trace/events/fscache.h | 4 ++++ 2 files changed, 14 insertions(+) diff --git a/fs/cachefiles/cache.c b/fs/cachefiles/cache.c index f449f7340aad..56ef519a36a0 100644 --- a/fs/cachefiles/cache.c +++ b/fs/cachefiles/cache.c @@ -8,6 +8,7 @@ #include #include #include +#include #include "internal.h" /* @@ -319,12 +320,20 @@ static void cachefiles_withdraw_volumes(struct cachefiles_cache *cache) _enter(""); for (;;) { + struct fscache_volume *vcookie = NULL; struct cachefiles_volume *volume = NULL; spin_lock(&cache->object_list_lock); if (!list_empty(&cache->volumes)) { volume = list_first_entry(&cache->volumes, struct cachefiles_volume, cache_link); + vcookie = fscache_try_get_volume(volume->vcookie, + fscache_volume_get_withdraw); + if (!vcookie) { + spin_unlock(&cache->object_list_lock); + cpu_relax(); + continue; + } list_del_init(&volume->cache_link); } spin_unlock(&cache->object_list_lock); @@ -332,6 +341,7 @@ static void cachefiles_withdraw_volumes(struct cachefiles_cache *cache) break; cachefiles_withdraw_volume(volume); + fscache_put_volume(vcookie, fscache_volume_put_withdraw); } _leave(""); diff --git a/include/trace/events/fscache.h b/include/trace/events/fscache.h index a6190aa1b406..f1a73aa83fbb 100644 --- a/include/trace/events/fscache.h +++ b/include/trace/events/fscache.h @@ -35,12 +35,14 @@ enum fscache_volume_trace { fscache_volume_get_cookie, fscache_volume_get_create_work, fscache_volume_get_hash_collision, + fscache_volume_get_withdraw, fscache_volume_free, fscache_volume_new_acquire, fscache_volume_put_cookie, fscache_volume_put_create_work, fscache_volume_put_hash_collision, fscache_volume_put_relinquish, + fscache_volume_put_withdraw, fscache_volume_see_create_work, fscache_volume_see_hash_wake, fscache_volume_wait_create_work, @@ -120,12 +122,14 @@ enum fscache_access_trace { EM(fscache_volume_get_cookie, "GET cook ") \ EM(fscache_volume_get_create_work, "GET creat") \ EM(fscache_volume_get_hash_collision, "GET hcoll") \ + EM(fscache_volume_get_withdraw, "GET withd") \ EM(fscache_volume_free, "FREE ") \ EM(fscache_volume_new_acquire, "NEW acq ") \ EM(fscache_volume_put_cookie, "PUT cook ") \ EM(fscache_volume_put_create_work, "PUT creat") \ EM(fscache_volume_put_hash_collision, "PUT hcoll") \ EM(fscache_volume_put_relinquish, "PUT relnq") \ + EM(fscache_volume_put_withdraw, "PUT withd") \ EM(fscache_volume_see_create_work, "SEE creat") \ EM(fscache_volume_see_hash_wake, "SEE hwake") \ E_(fscache_volume_wait_create_work, "WAIT crea") From patchwork Wed May 22 11:59:09 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baokun Li X-Patchwork-Id: 13670396 Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7C0306026A; Wed, 22 May 2024 04:06:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716350763; cv=none; b=SFcKe6lydJq28e/BS+Mv1T60GB4wjFFTVWfuanFuHGSnP6W5rf8eUr+B5sc95N1wV6/SyaPXUt+kUGKirBdfY6mX+c5LdrqLCan6C5wjlppKFFawd70hMRlpJD8l4oLgNbuwZVvKq2pPh/OlCEC0xc6aYLFItkn5xuCnglfRNRw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716350763; c=relaxed/simple; bh=EeUTOXX+ikXI0gUddRBFhNlS1L6H+hG/JmTeVZ9ra6M=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=PdMr4/CkXTKl970WM4H1rHqllLeRGPd3ZuJiKs2IlS7Xrukz+1mESCAGAFu5UT3a1D+2ZrMdSab/flI3j0iPvO9FxH+TW48G0xkVsK6EgvtVSNNCBJ5Fvn05BjhDd/eUqvPb1wSGYhSp688nwSTIeyvdYwzUZhQBjmUQhEGNvho= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.235]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4Vkd5D48D3z4f3k5s; Wed, 22 May 2024 12:05:52 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.112]) by mail.maildlp.com (Postfix) with ESMTP id 5C7321A094F; Wed, 22 May 2024 12:05:58 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP1 (Coremail) with SMTP id cCh0CgBHZQ4ib01ms1VYNQ--.24441S7; Wed, 22 May 2024 12:05:58 +0800 (CST) From: libaokun@huaweicloud.com To: netfs@lists.linux.dev, dhowells@redhat.com, jlayton@kernel.org Cc: hsiangkao@linux.alibaba.com, jefflexu@linux.alibaba.com, zhujia.zj@bytedance.com, linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, libaokun@huaweicloud.com, yangerkun@huawei.com, houtao1@huawei.com, yukuai3@huawei.com, wozizhi@huawei.com, Baokun Li Subject: [PATCH RESEND 3/5] cachefiles: fix slab-use-after-free in cachefiles_withdraw_cookie() Date: Wed, 22 May 2024 19:59:09 +0800 Message-Id: <20240522115911.2403021-4-libaokun@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240522115911.2403021-1-libaokun@huaweicloud.com> References: <20240522115911.2403021-1-libaokun@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: cCh0CgBHZQ4ib01ms1VYNQ--.24441S7 X-Coremail-Antispam: 1UD129KBjvJXoWxtr1DXw1fuFWfXw13Zr45Awb_yoW7Ary3pF ZIvrWxtrW8W3y7Grs8Jw1UJrn3J3s8JanrXw18Xr1rAws5Zr1YqF1jyr1YvFy5CrWkArs2 y3WUKFy7WryUArJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUQF14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2jI8I6cxK62vIxIIY0VWUZVW8XwA2048vs2IY02 0E87I2jVAFwI0_JrWl82xGYIkIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2 F7IY1VAKz4vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjx v20xvEc7CjxVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2 z280aVCY1x0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0V AKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1l Ox8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErc IFxwACI402YVCY1x02628vn2kIc2xKxwAKzVCY07xG64k0F24l42xK82IYc2Ij64vIr41l 4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67 AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8I cVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26F4j6r4UJwCI42IY6xAIw20EY4 v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z280aVCY1x0267AK xVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x0pRgo7tUUUUU= X-CM-SenderInfo: 5olet0hnxqqx5xdzvxpfor3voofrz/ From: Baokun Li We got the following issue in our fault injection stress test: ================================================================== BUG: KASAN: slab-use-after-free in cachefiles_withdraw_cookie+0x4d9/0x600 Read of size 8 at addr ffff888118efc000 by task kworker/u78:0/109 CPU: 13 PID: 109 Comm: kworker/u78:0 Not tainted 6.8.0-dirty #566 Call Trace: kasan_report+0x93/0xc0 cachefiles_withdraw_cookie+0x4d9/0x600 fscache_cookie_state_machine+0x5c8/0x1230 fscache_cookie_worker+0x91/0x1c0 process_one_work+0x7fa/0x1800 [...] Allocated by task 117: kmalloc_trace+0x1b3/0x3c0 cachefiles_acquire_volume+0xf3/0x9c0 fscache_create_volume_work+0x97/0x150 process_one_work+0x7fa/0x1800 [...] Freed by task 120301: kfree+0xf1/0x2c0 cachefiles_withdraw_cache+0x3fa/0x920 cachefiles_put_unbind_pincount+0x1f6/0x250 cachefiles_daemon_release+0x13b/0x290 __fput+0x204/0xa00 task_work_run+0x139/0x230 do_exit+0x87a/0x29b0 [...] ================================================================== Following is the process that triggers the issue: p1 | p2 ------------------------------------------------------------ fscache_begin_lookup fscache_begin_volume_access fscache_cache_is_live(fscache_cache) cachefiles_daemon_release cachefiles_put_unbind_pincount cachefiles_daemon_unbind cachefiles_withdraw_cache fscache_withdraw_cache fscache_set_cache_state(cache, FSCACHE_CACHE_IS_WITHDRAWN); cachefiles_withdraw_objects(cache) fscache_wait_for_objects(fscache) atomic_read(&fscache_cache->object_count) == 0 fscache_perform_lookup cachefiles_lookup_cookie cachefiles_alloc_object refcount_set(&object->ref, 1); object->volume = volume fscache_count_object(vcookie->cache); atomic_inc(&fscache_cache->object_count) cachefiles_withdraw_volumes cachefiles_withdraw_volume fscache_withdraw_volume __cachefiles_free_volume kfree(cachefiles_volume) fscache_cookie_state_machine cachefiles_withdraw_cookie cache = object->volume->cache; // cachefiles_volume UAF !!! After setting FSCACHE_CACHE_IS_WITHDRAWN, wait for all the cookie lookups to complete first, and then wait for fscache_cache->object_count == 0 to avoid the cookie exiting after the volume has been freed and triggering the above issue. Therefore call fscache_withdraw_volume() before calling cachefiles_withdraw_objects(). This way, after setting FSCACHE_CACHE_IS_WITHDRAWN, only the following two cases will occur: 1) fscache_begin_lookup fails in fscache_begin_volume_access(). 2) fscache_withdraw_volume() will ensure that fscache_count_object() has been executed before calling fscache_wait_for_objects(). Fixes: fe2140e2f57f ("cachefiles: Implement volume support") Suggested-by: Hou Tao Signed-off-by: Baokun Li --- fs/cachefiles/cache.c | 35 ++++++++++++++++++++++++++++++++++- fs/cachefiles/volume.c | 1 - 2 files changed, 34 insertions(+), 2 deletions(-) diff --git a/fs/cachefiles/cache.c b/fs/cachefiles/cache.c index 56ef519a36a0..9fb06dc16520 100644 --- a/fs/cachefiles/cache.c +++ b/fs/cachefiles/cache.c @@ -313,7 +313,39 @@ static void cachefiles_withdraw_objects(struct cachefiles_cache *cache) } /* - * Withdraw volumes. + * Withdraw fscache volumes. + */ +static void cachefiles_withdraw_fscache_volumes(struct cachefiles_cache *cache) +{ + struct list_head *cur; + struct cachefiles_volume *volume; + struct fscache_volume *vcookie; + + _enter(""); +retry: + spin_lock(&cache->object_list_lock); + list_for_each(cur, &cache->volumes) { + volume = list_entry(cur, struct cachefiles_volume, cache_link); + + if (atomic_read(&volume->vcookie->n_accesses) == 0) + continue; + + vcookie = fscache_try_get_volume(volume->vcookie, + fscache_volume_get_withdraw); + if (vcookie) { + spin_unlock(&cache->object_list_lock); + fscache_withdraw_volume(vcookie); + fscache_put_volume(vcookie, fscache_volume_put_withdraw); + goto retry; + } + } + spin_unlock(&cache->object_list_lock); + + _leave(""); +} + +/* + * Withdraw cachefiles volumes. */ static void cachefiles_withdraw_volumes(struct cachefiles_cache *cache) { @@ -381,6 +413,7 @@ void cachefiles_withdraw_cache(struct cachefiles_cache *cache) pr_info("File cache on %s unregistering\n", fscache->name); fscache_withdraw_cache(fscache); + cachefiles_withdraw_fscache_volumes(cache); /* we now have to destroy all the active objects pertaining to this * cache - which we do by passing them off to thread pool to be diff --git a/fs/cachefiles/volume.c b/fs/cachefiles/volume.c index 89df0ba8ba5e..781aac4ef274 100644 --- a/fs/cachefiles/volume.c +++ b/fs/cachefiles/volume.c @@ -133,7 +133,6 @@ void cachefiles_free_volume(struct fscache_volume *vcookie) void cachefiles_withdraw_volume(struct cachefiles_volume *volume) { - fscache_withdraw_volume(volume->vcookie); 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Wed, 22 May 2024 12:05:58 +0800 (CST) From: libaokun@huaweicloud.com To: netfs@lists.linux.dev, dhowells@redhat.com, jlayton@kernel.org Cc: hsiangkao@linux.alibaba.com, jefflexu@linux.alibaba.com, zhujia.zj@bytedance.com, linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, libaokun@huaweicloud.com, yangerkun@huawei.com, houtao1@huawei.com, yukuai3@huawei.com, wozizhi@huawei.com, Baokun Li Subject: [PATCH RESEND 4/5] cachefiles: correct the return value of cachefiles_check_volume_xattr() Date: Wed, 22 May 2024 19:59:10 +0800 Message-Id: <20240522115911.2403021-5-libaokun@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240522115911.2403021-1-libaokun@huaweicloud.com> References: <20240522115911.2403021-1-libaokun@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: cCh0CgBHZQ4ib01ms1VYNQ--.24441S8 X-Coremail-Antispam: 1UD129KBjvdXoWrZFyrAFW5Cw4xuw4kZF13urg_yoWkZwc_uF 9xAF4UZrs3Gr48JrsrAa42qrWSqr1UCwn8Jr1Yva13tws8KrW5XFWDtr9xAr17Wr4DK3Wq kryxZF13Xr9FgjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbmkFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k26cxKx2IYs7xG 6rWj6s0DM7CIcVAFz4kK6r1j6r18M280x2IEY4vEnII2IxkI6r1a6r45M28IrcIa0xkI8V A2jI8067AKxVWUAVCq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJ M28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4x0Y4vE2I x0cI8IcVCY1x0267AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK 6I8E87Iv6xkF7I0E14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4 xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8 JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20V AGYxC7M4IIrI8v6xkF7I0E8cxan2IY04v7M4kE6xkIj40Ew7xC0wCF04k20xvY0x0EwIxG rwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4 vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAIcVC0I7IY x2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Cr0_Gr1UMIIF0xvE42xK8V AvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVW8JVWxJwCI42IY6I8E87Iv6xkF7I0E 14v26r4UJVWxJrUvcSsGvfC2KfnxnUUI43ZEXa7sREMKZDUUUUU== X-CM-SenderInfo: 5olet0hnxqqx5xdzvxpfor3voofrz/ From: Baokun Li In cachefiles_check_volume_xattr(), the error returned by vfs_getxattr is not passed to ret, so it ends up returning -ESTALE, which leads to an endless loop as follows: cachefiles_acquire_volume retry: cachefiles_check_volume_xattr // return -ESTALE cachefiles_bury_object // EIO causes rename failure goto retry; So pass the error code to ret when xlen < 0 to avoid the above problem. Fixes: 32e150037dce ("fscache, cachefiles: Store the volume coherency data") Signed-off-by: Baokun Li --- fs/cachefiles/xattr.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/cachefiles/xattr.c b/fs/cachefiles/xattr.c index bcb6173943ee..20e4a4391090 100644 --- a/fs/cachefiles/xattr.c +++ b/fs/cachefiles/xattr.c @@ -252,6 +252,7 @@ int cachefiles_check_volume_xattr(struct cachefiles_volume *volume) xlen = vfs_getxattr(&nop_mnt_idmap, dentry, cachefiles_xattr_cache, buf, len); if (xlen != len) { if (xlen < 0) { + ret = xlen; trace_cachefiles_vfs_error(NULL, d_inode(dentry), xlen, cachefiles_trace_getxattr_error); if (xlen == -EIO) From patchwork Wed May 22 11:59:11 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baokun Li X-Patchwork-Id: 13670398 Received: from dggsgout12.his.huawei.com (unknown [45.249.212.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 713D637144; Wed, 22 May 2024 04:06:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.56 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716350763; cv=none; b=tyZBvUmfGrdmnnb9hAYMZNY6agzJT6fq4cnNC+Nty0DIFiHBMZ33sDcHxtU+uJ7MbGCXjPqnee8KlGnabIdEv3BnrPSJJ/Dmq8fsKjrDS55i0MrUmmLFQdx8kMeHNp1pwwcOT0TfTItpo4FfFpwLrF+3JflYsW0CZhq1gYmro3s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716350763; c=relaxed/simple; bh=eYmI2UoND9NW9g+AeXxMK4ItoLkzH/5fFHbVVsjmXDU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=thmga0iNjnzVyxi1WF3Eb/YEQD1dc4dGnh/IWiI5g/To+pLDeiTp1MmxXgLXXyi2B+Ni9FwFZphD7KMAwqjIJ1aMX+Ri8RJrviWjkc1ChK4PK2WM9lR7kPybw/PNb9Gs8erZKjg9m4xHCOTt57DEI41tqoUMuvVM/2Dp1OUuNHU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.216]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4Vkd5B4Ggqz4f3jdN; Wed, 22 May 2024 12:05:50 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.112]) by mail.maildlp.com (Postfix) with ESMTP id 877851A04C2; Wed, 22 May 2024 12:05:59 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP1 (Coremail) with SMTP id cCh0CgBHZQ4ib01ms1VYNQ--.24441S9; Wed, 22 May 2024 12:05:59 +0800 (CST) From: libaokun@huaweicloud.com To: netfs@lists.linux.dev, dhowells@redhat.com, jlayton@kernel.org Cc: hsiangkao@linux.alibaba.com, jefflexu@linux.alibaba.com, zhujia.zj@bytedance.com, linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, libaokun@huaweicloud.com, yangerkun@huawei.com, houtao1@huawei.com, yukuai3@huawei.com, wozizhi@huawei.com, Baokun Li Subject: [PATCH RESEND 5/5] cachefiles: correct the return value of cachefiles_check_auxdata() Date: Wed, 22 May 2024 19:59:11 +0800 Message-Id: <20240522115911.2403021-6-libaokun@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240522115911.2403021-1-libaokun@huaweicloud.com> References: <20240522115911.2403021-1-libaokun@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: cCh0CgBHZQ4ib01ms1VYNQ--.24441S9 X-Coremail-Antispam: 1UD129KBjvdXoW7JFykurWUAF4kCF4DAr4xWFg_yoWfKFX_uF Z7Ar4xXr4fGr4kJwsrA3y2qrWvqr1xAwn8Kr1Fgry2yw1aqFZ8XFWDtr98Ar1UWr4UK3WD trZ7ZF13WF9FgjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbmkFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k26cxKx2IYs7xG 6rWj6s0DM7CIcVAFz4kK6r1j6r18M280x2IEY4vEnII2IxkI6r1a6r45M28IrcIa0xkI8V A2jI8067AKxVWUAVCq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJ M28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4x0Y4vE2I x0cI8IcVCY1x0267AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK 6I8E87Iv6xkF7I0E14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4 xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8 JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20V AGYxC7M4IIrI8v6xkF7I0E8cxan2IY04v7M4kE6xkIj40Ew7xC0wCF04k20xvY0x0EwIxG rwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4 vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAIcVC0I7IY x2IY67AKxVWUCVW8JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Cr0_Gr1UMIIF0xvE42xK8V AvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVW8JVWxJwCI42IY6I8E87Iv6xkF7I0E 14v26r4UJVWxJrUvcSsGvfC2KfnxnUUI43ZEXa7sREMKZDUUUUU== X-CM-SenderInfo: 5olet0hnxqqx5xdzvxpfor3voofrz/ From: Baokun Li Pass the error code to ret when xlen < 0 to avoid misleading the caller. Fixes: 72b957856b0c ("cachefiles: Implement metadata/coherency data storage in xattrs") Signed-off-by: Baokun Li --- fs/cachefiles/xattr.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/cachefiles/xattr.c b/fs/cachefiles/xattr.c index 20e4a4391090..4dd8a993c60a 100644 --- a/fs/cachefiles/xattr.c +++ b/fs/cachefiles/xattr.c @@ -110,9 +110,11 @@ int cachefiles_check_auxdata(struct cachefiles_object *object, struct file *file if (xlen == 0) xlen = vfs_getxattr(&nop_mnt_idmap, dentry, cachefiles_xattr_cache, buf, tlen); if (xlen != tlen) { - if (xlen < 0) + if (xlen < 0) { + ret = xlen; trace_cachefiles_vfs_error(object, file_inode(file), xlen, cachefiles_trace_getxattr_error); + } if (xlen == -EIO) cachefiles_io_error_obj( object,