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[146.115.88.66]) by smtp.gmail.com with ESMTPSA id l189sm17094407qke.67.2020.08.02.09.55.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 02 Aug 2020 09:55:38 -0700 (PDT) Date: Sun, 2 Aug 2020 12:55:35 -0400 From: Peilin Ye To: Dan Carpenter Cc: Arnd Bergmann , Greg Kroah-Hartman , linux-kernel-mentees@lists.linuxfoundation.org, "linux-kernel@vger.kernel.org" Subject: Re: [Linux-kernel-mentees] [PATCH v3] media/v4l2-core: Fix kernel-infoleak in video_put_user() Message-ID: <20200802165535.GA270694@PWN> References: <20200726220557.102300-1-yepeilin.cs@gmail.com> <20200726222703.102701-1-yepeilin.cs@gmail.com> <20200727131608.GD1913@kadam> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200727131608.GD1913@kadam> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 27, 2020 at 04:16:08PM +0300, Dan Carpenter wrote: > kernel/signal.c:3524 __do_sys_rt_sigtimedwait() warn: check that 'info' doesn't leak information (struct has a hole after 'si_code') > kernel/signal.c:3524 __do_sys_rt_sigtimedwait() warn: check that 'info' doesn't leak information (struct has a hole after 'si_code') > kernel/signal.c:3556 __do_sys_rt_sigtimedwait_time32() warn: check that 'info' doesn't leak information (struct has a hole after 'si_code') > kernel/signal.c:3556 __do_sys_rt_sigtimedwait_time32() warn: check that 'info' doesn't leak information (struct has a hole after 'si_code') I think these are safe. Before getting to copy_siginfo_to_user(), all `info` run through: do_sigtimedwait() V dequeue_signal() V __dequeue_signal() V collect_signal() Where it either gets memcpy()'d by copy_siginfo(), or memset()'d by clear_siginfo(). The only exception is when next_signal() fails in __dequeue_signal(), but that will cause do_sigtimedwait() to return an error, and we never reach copy_siginfo_to_user() in such a case. Thank you, Peilin Ye