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[52.52.7.82]) by smtp.gmail.com with ESMTPSA id x22-20020a05622a001600b0033d1ac2517esm1260993qtw.64.2022.08.02.22.03.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Aug 2022 22:03:02 -0700 (PDT) From: Peilin Ye To: Jens Axboe , Pavel Begunkov , Paul Moore , Eric Paris Cc: Peilin Ye , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, linux-audit@redhat.com, Peilin Ye Subject: [PATCH] audit, io_uring, io-wq: Fix memory leak in io_sq_thread() and io_wqe_worker() Date: Tue, 2 Aug 2022 22:02:30 -0700 Message-Id: <20220803050230.30152-1-yepeilin.cs@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org From: Peilin Ye Currently @audit_context is allocated twice for io_uring workers: 1. copy_process() calls audit_alloc(); 2. io_sq_thread() or io_wqe_worker() calls audit_alloc_kernel() (which is effectively audit_alloc()) and overwrites @audit_context, causing: BUG: memory leak unreferenced object 0xffff888144547400 (size 1024): <...> hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [] audit_alloc+0x133/0x210 [] copy_process+0xcd3/0x2340 [] create_io_thread+0x63/0x90 [] create_io_worker+0xb4/0x230 [] io_wqe_enqueue+0x248/0x3b0 [] io_queue_iowq+0xba/0x200 [] io_queue_async+0x113/0x180 [] io_req_task_submit+0x18f/0x1a0 [] io_apoll_task_func+0xdd/0x120 [] tctx_task_work+0x11f/0x570 [] task_work_run+0x7e/0xc0 [] get_signal+0xc18/0xf10 [] arch_do_signal_or_restart+0x2b/0x730 [] exit_to_user_mode_prepare+0x5e/0x180 [] syscall_exit_to_user_mode+0x12/0x20 [] do_syscall_64+0x40/0x80 Then, 3. io_sq_thread() or io_wqe_worker() frees @audit_context using audit_free(); 4. do_exit() eventually calls audit_free() again, which is okay because audit_free() does a NULL check. Free the old @audit_context first in audit_alloc_kernel(), and delete the redundant calls to audit_free() for less confusion. Fixes: 5bd2182d58e9 ("audit,io_uring,io-wq: add some basic audit support to io_uring") Cc: stable@vger.kernel.org Signed-off-by: Peilin Ye --- Hi all, A better way to fix this memleak would probably be checking @args->io_thread in copy_process()? Something like: if (args->io_thread) retval = audit_alloc_kernel(); else retval = audit_alloc(); But I didn't want to add another if to copy_process() for this bugfix. Please suggest, thanks! Peilin Ye fs/io-wq.c | 1 - fs/io_uring.c | 2 -- kernel/auditsc.c | 1 + 3 files changed, 1 insertion(+), 3 deletions(-) diff --git a/fs/io-wq.c b/fs/io-wq.c index 824623bcf1a5..0f4804a5e873 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -670,7 +670,6 @@ static int io_wqe_worker(void *data) if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) io_worker_handle_work(worker); - audit_free(current); io_worker_exit(worker); return 0; } diff --git a/fs/io_uring.c b/fs/io_uring.c index e8e769be9ed0..0f27914f37f2 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -9283,8 +9283,6 @@ static int io_sq_thread(void *data) io_run_task_work(); mutex_unlock(&sqd->lock); - audit_free(current); - complete(&sqd->exited); do_exit(0); } diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 3a8c9d744800..7948090fd12f 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -1095,6 +1095,7 @@ int audit_alloc_kernel(struct task_struct *tsk) * 2. The {set,clear}_task_syscall_work() ops likely have zero effect * on these internal kernel tasks, but they probably don't hurt either. */ + __audit_free(current); return audit_alloc(tsk); } -- 2.20.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4F6BBC19F28 for ; Wed, 3 Aug 2022 13:14:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1659532452; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding:list-id:list-help: list-unsubscribe:list-subscribe:list-post; bh=y4/c1Cqq6StZA0WUbHE4jSupXB1bLFR8GTEKfAc5Id0=; b=O7U8oiL3a1N4tkqD03Ah/Q9SBQM5UtwU68QTUCiwqxwJF9gIvD2evK4s3slmIJl6Nvf+PZ KKm6NnQf8wBzGsV03llmCM+8KgQidjRZE/lenBP8AJqu628XQ4MqbDoPgbLdw+MX0JGhen dxgs98VaZzSbYJh1Nx/riQXxVPCgaX8= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-612-wEXdyFnFNpi4GPDHpTn_gQ-1; Wed, 03 Aug 2022 09:14:09 -0400 X-MC-Unique: wEXdyFnFNpi4GPDHpTn_gQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D53991C1F1E2; Wed, 3 Aug 2022 13:14:07 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (unknown [10.30.29.100]) by smtp.corp.redhat.com (Postfix) with ESMTP id 595052026D4C; Wed, 3 Aug 2022 13:14:06 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (localhost [IPv6:::1]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 363241946A52; Wed, 3 Aug 2022 13:14:06 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 507F71946A77 for ; Wed, 3 Aug 2022 05:03:05 +0000 (UTC) Received: by smtp.corp.redhat.com (Postfix) id 1E17AC28100; Wed, 3 Aug 2022 05:03:05 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast07.extmail.prod.ext.rdu2.redhat.com [10.11.55.23]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1A732C27DB3 for ; Wed, 3 Aug 2022 05:03:05 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-1.mimecast.com [207.211.31.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 024543C11E6C for ; Wed, 3 Aug 2022 05:03:05 +0000 (UTC) Received: from mail-qk1-f180.google.com (mail-qk1-f180.google.com [209.85.222.180]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-675-fdne5PhUO0ObhkjkBxuC7w-1; Wed, 03 Aug 2022 01:03:03 -0400 X-MC-Unique: fdne5PhUO0ObhkjkBxuC7w-1 Received: by mail-qk1-f180.google.com with SMTP id o1so12098504qkg.9; Tue, 02 Aug 2022 22:03:03 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=uVXW0Uy4uUbhDpgN7+ORPCX7CU++KL6atoUXVVGMX04=; b=e4G/DCjr9EmYsvlyFs++BPdcCLjhkcGkxWhFSkgm98/Ls6NWnLHQ0fOFTLOP2L5mic KnUdbQqVshOi8lYM+ocDpbDaYeNmM8sJluG/nuzMmFEAldxwzs0wh2EKk6PXBA2zbk+/ CxHniFIEVNn+LBOGqk2KMDJ89Gl6OmHoO8VUfvDn2+OWR1bBtPrSzF4C/VKM+iMX7cL5 0n85uui0tn8j/s3CxkDKDjb+pVFdkoaWkikJJsjq7m8qVc7TK/gNdioTCn8xIxMsVykm Z/h3ssytP40E20Eso/2cdm2GlzIx+d8MvfaEwVIQpYrXL/WwLpi77kMT/Fi1D5R1/pxd jZzg== X-Gm-Message-State: AJIora+ZZTYTq2g49aqmfDAg2yDSYL2sfovW8r0/YUZUvvyi+ZDtz45W BP0HLZk9SkVLta7aRpvgtw== X-Google-Smtp-Source: AGRyM1v8I+fKQMI8kklagMtT2p4ecs0kmq7Ny6EvoPp7eDjY/UgwGMfIhAg4BcHt6sb1s8CEB/8jTQ== X-Received: by 2002:a05:620a:138b:b0:6b5:d5eb:aabf with SMTP id k11-20020a05620a138b00b006b5d5ebaabfmr17334494qki.393.1659502982588; Tue, 02 Aug 2022 22:03:02 -0700 (PDT) Received: from bytedance.attlocal.net (ec2-52-52-7-82.us-west-1.compute.amazonaws.com. [52.52.7.82]) by smtp.gmail.com with ESMTPSA id x22-20020a05622a001600b0033d1ac2517esm1260993qtw.64.2022.08.02.22.03.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Aug 2022 22:03:02 -0700 (PDT) From: Peilin Ye To: Jens Axboe , Pavel Begunkov , Paul Moore , Eric Paris Subject: [PATCH] audit, io_uring, io-wq: Fix memory leak in io_sq_thread() and io_wqe_worker() Date: Tue, 2 Aug 2022 22:02:30 -0700 Message-Id: <20220803050230.30152-1-yepeilin.cs@gmail.com> MIME-Version: 1.0 X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.85 on 10.11.54.8 X-Mailman-Approved-At: Wed, 03 Aug 2022 13:14:05 +0000 X-BeenThere: linux-audit@redhat.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux Audit Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peilin Ye , linux-audit@redhat.com, Peilin Ye , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Errors-To: linux-audit-bounces@redhat.com Sender: "Linux-audit" X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit From: Peilin Ye Currently @audit_context is allocated twice for io_uring workers: 1. copy_process() calls audit_alloc(); 2. io_sq_thread() or io_wqe_worker() calls audit_alloc_kernel() (which is effectively audit_alloc()) and overwrites @audit_context, causing: BUG: memory leak unreferenced object 0xffff888144547400 (size 1024): <...> hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [] audit_alloc+0x133/0x210 [] copy_process+0xcd3/0x2340 [] create_io_thread+0x63/0x90 [] create_io_worker+0xb4/0x230 [] io_wqe_enqueue+0x248/0x3b0 [] io_queue_iowq+0xba/0x200 [] io_queue_async+0x113/0x180 [] io_req_task_submit+0x18f/0x1a0 [] io_apoll_task_func+0xdd/0x120 [] tctx_task_work+0x11f/0x570 [] task_work_run+0x7e/0xc0 [] get_signal+0xc18/0xf10 [] arch_do_signal_or_restart+0x2b/0x730 [] exit_to_user_mode_prepare+0x5e/0x180 [] syscall_exit_to_user_mode+0x12/0x20 [] do_syscall_64+0x40/0x80 Then, 3. io_sq_thread() or io_wqe_worker() frees @audit_context using audit_free(); 4. do_exit() eventually calls audit_free() again, which is okay because audit_free() does a NULL check. Free the old @audit_context first in audit_alloc_kernel(), and delete the redundant calls to audit_free() for less confusion. Fixes: 5bd2182d58e9 ("audit,io_uring,io-wq: add some basic audit support to io_uring") Cc: stable@vger.kernel.org Signed-off-by: Peilin Ye --- Hi all, A better way to fix this memleak would probably be checking @args->io_thread in copy_process()? Something like: if (args->io_thread) retval = audit_alloc_kernel(); else retval = audit_alloc(); But I didn't want to add another if to copy_process() for this bugfix. Please suggest, thanks! Peilin Ye fs/io-wq.c | 1 - fs/io_uring.c | 2 -- kernel/auditsc.c | 1 + 3 files changed, 1 insertion(+), 3 deletions(-) diff --git a/fs/io-wq.c b/fs/io-wq.c index 824623bcf1a5..0f4804a5e873 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -670,7 +670,6 @@ static int io_wqe_worker(void *data) if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) io_worker_handle_work(worker); - audit_free(current); io_worker_exit(worker); return 0; } diff --git a/fs/io_uring.c b/fs/io_uring.c index e8e769be9ed0..0f27914f37f2 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -9283,8 +9283,6 @@ static int io_sq_thread(void *data) io_run_task_work(); mutex_unlock(&sqd->lock); - audit_free(current); - complete(&sqd->exited); do_exit(0); } diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 3a8c9d744800..7948090fd12f 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -1095,6 +1095,7 @@ int audit_alloc_kernel(struct task_struct *tsk) * 2. The {set,clear}_task_syscall_work() ops likely have zero effect * on these internal kernel tasks, but they probably don't hurt either. */ + __audit_free(current); return audit_alloc(tsk); } -- 2.20.1 -- Linux-audit mailing list Linux-audit@redhat.com https://listman.redhat.com/mailman/listinfo/linux-audit