From patchwork Thu Sep 17 15:28:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 11782825 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EC9016CA for ; Thu, 17 Sep 2020 15:49:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D5D7D20838 for ; Thu, 17 Sep 2020 15:49:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728231AbgIQPsI (ORCPT ); Thu, 17 Sep 2020 11:48:08 -0400 Received: from mout.kundenserver.de ([212.227.126.187]:60775 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728182AbgIQPr2 (ORCPT ); Thu, 17 Sep 2020 11:47:28 -0400 Received: from threadripper.lan ([149.172.98.151]) by mrelayeu.kundenserver.de (mreue011 [212.227.15.129]) with ESMTPA (Nemesis) id 1MUGuZ-1jrobq3GTr-00REDu; Thu, 17 Sep 2020 17:28:25 +0200 From: Arnd Bergmann To: linux-media@vger.kernel.org, mchehab@kernel.org, hverkuil@xs4all.nl Cc: hch@lst.de, linux-kernel@vger.kernel.org, Arnd Bergmann Subject: [PATCH 1/8] media: v4l2: prepare compat-ioctl rework Date: Thu, 17 Sep 2020 17:28:16 +0200 Message-Id: <20200917152823.1241599-2-arnd@arndb.de> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200917152823.1241599-1-arnd@arndb.de> References: <20200917152823.1241599-1-arnd@arndb.de> MIME-Version: 1.0 X-Provags-ID: V03:K1:jLtivs9oR8yT4Amv6wUYDZEGU94xByx2XLV3rL1lfaEk9Rp9+Y+ WK3WkMVSuoxZ4WqzGptxXOYUsHq/yU0Ir+Eb+eb5Irthl2pfOAJ1BsroP4TxgXQ1zDE38dN m5MPdrfXJa5WltPdIWNLsYFjoVdA0lZE5lJ2jOTEPKz23UeauqCc9m4s5zJ0pBcOY7Cj1yL +sHUaUJkEhAXioDNGQfaw== X-Spam-Flag: NO X-UI-Out-Filterresults: notjunk:1;V03:K0:YI0J0n/IYhs=:Gp7a2T2SN9riD8XPq3IFFb nawAq1JW3IPOCyOjrmW53ukdOaYG4m4ONpp6PzLIdIFDzRsyNsHANSxxha5Nb7sDg8YwZHhDo L6+c26QUicAGug4l2hNmVyt3xUF7xV6IKey5q0mZsLsKMlHgs5qheO8td1eIEa+JLi6ILk0S8 8WUiFZex7BvNhQxCPFHpnCDcyLSDEnVz7SMycgV3L0b0AjDX6EKb/FwZdz01yzZXN/WoQYbEd GEtnm+DO1jfp/c1RN6HzDCHSePEVwWMbaXMyAttxiyGJS66o9+KnB6v6If8/rKZXG+mZbUjOq 1w0CpAwJbV6YvwtVPErsOX8iFY3JgFP8w1zz6h/9NVS5sjmes62Kzfmv5c9OQTUpiuAuXZ9Wy v2Y2ZoDYobyLP0LzSg9IyyEvuN7aM6GScELlY+fAoFhLp6gVbtP1WIsZiywE4tl4jU5eG+1JM Cua/fTkDZ/bSxkPu+zL76reFUoGbnDwGJCWhnfHms89BJtdCb4buIazrtPUJxf3yQ+yh1uUPP whz3bM5yxiXlkCtFYoalZA5vSw6PJWFv93lpw/DFWO2tT0GYPrfPPx0eoMhHgTeKHtIZ/wab+ j0kLoJZjCgiodu7BVYvW57sajLiOI+9gFSH02YM4Afwp2smJmY/4Nk9zMp8ZEE+6IfzgMuj0i 47B1fbWNkfqw9xa0u7R1zActOI+Dci+vsbqdGihSu5ZLPThnLC5Y9buEcPgws/0FelgK3k6dX rERvBtw+7ySAwa6g3cUdPVURfESyrfRiYHhm+AgwLjY9qkw3ex911dBqucd+vfN68nNkXuudR njltFKh86q0w0HL/PrcVVHq2aR2mwuhatWEfiNlqJMPDZctrgSoXDSKJ+GPDu1bIUdHREod Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org The v4l2-compat-ioctl32() currently takes an extra round trip through user space pointers when converting the data structure formats. In particular, this involves using the compat_alloc_user_space() and copy_in_user() helpers that often lead to worse compat handlers compared to using in_compat_syscall() checks when copying the data. The native implementation already gained a simpler method to deal with the conversion for the time32 conversion. Hook into the same places to provide a location for reading and writing user space data from inside of the generic video_usercopy() helper. Signed-off-by: Arnd Bergmann --- drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 53 ++++++++++ drivers/media/v4l2-core/v4l2-ioctl.c | 97 ++++++++++++------- include/media/v4l2-ioctl.h | 11 +++ 3 files changed, 125 insertions(+), 36 deletions(-) diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c index 593bcf6c3735..8f2cb03be48b 100644 --- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c @@ -1420,6 +1420,59 @@ static int put_v4l2_edid32(struct v4l2_edid __user *p64, #define VIDIOC_G_OUTPUT32 _IOR ('V', 46, s32) #define VIDIOC_S_OUTPUT32 _IOWR('V', 47, s32) +unsigned int v4l2_compat_translate_cmd(unsigned int cmd) +{ + switch (cmd) { + } + return cmd; +} + +int v4l2_compat_get_user(void __user *arg, void *parg, unsigned int cmd) +{ + switch (cmd) { + } + return 0; +} + +int v4l2_compat_put_user(void __user *arg, void *parg, unsigned int cmd) +{ + switch (cmd) { + } + return 0; +} + +int v4l2_compat_get_array_args(struct file *file, void *mbuf, + void __user *user_ptr, size_t array_size, + unsigned int cmd, void *arg) +{ + int err = 0; + + switch (cmd) { + default: + if (copy_from_user(mbuf, user_ptr, array_size)) + err = -EFAULT; + break; + } + + return err; +} + +int v4l2_compat_put_array_args(struct file *file, void __user *user_ptr, + void *mbuf, size_t array_size, + unsigned int cmd, void *arg) +{ + int err = 0; + + switch (cmd) { + default: + if (copy_to_user(user_ptr, mbuf, array_size)) + err = -EFAULT; + break; + } + + return err; +} + /** * alloc_userspace() - Allocates a 64-bits userspace pointer compatible * for calling the native 64-bits version of an ioctl. diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c index a556880f225a..4e79cdac9a5f 100644 --- a/drivers/media/v4l2-core/v4l2-ioctl.c +++ b/drivers/media/v4l2-core/v4l2-ioctl.c @@ -8,6 +8,7 @@ * Mauro Carvalho Chehab (version 2) */ +#include #include #include #include @@ -3103,11 +3104,14 @@ static unsigned int video_translate_cmd(unsigned int cmd) return VIDIOC_PREPARE_BUF; #endif } + if (in_compat_syscall()) + return v4l2_compat_translate_cmd(cmd); return cmd; } -static int video_get_user(void __user *arg, void *parg, unsigned int cmd, +static int video_get_user(void __user *arg, void *parg, + unsigned int real_cmd, unsigned int cmd, bool *always_copy) { unsigned int n = _IOC_SIZE(cmd); @@ -3118,6 +3122,34 @@ static int video_get_user(void __user *arg, void *parg, unsigned int cmd, return 0; } + if (cmd == real_cmd) { + /* + * In some cases, only a few fields are used as input, + * i.e. when the app sets "index" and then the driver + * fills in the rest of the structure for the thing + * with that index. We only need to copy up the first + * non-input field. + */ + if (v4l2_is_known_ioctl(cmd)) { + u32 flags = v4l2_ioctls[_IOC_NR(cmd)].flags; + + if (flags & INFO_FL_CLEAR_MASK) + n = (flags & INFO_FL_CLEAR_MASK) >> 16; + *always_copy = flags & INFO_FL_ALWAYS_COPY; + } + + if (copy_from_user(parg, (void __user *)arg, n)) + return -EFAULT; + + /* zero out anything we don't copy from userspace */ + if (n < _IOC_SIZE(cmd)) + memset((u8 *)parg + n, 0, _IOC_SIZE(cmd) - n); + return 0; + } + + if (in_compat_syscall()) + return v4l2_compat_get_user(arg, parg, cmd); + switch (cmd) { #ifdef CONFIG_COMPAT_32BIT_TIME case VIDIOC_QUERYBUF_TIME32: @@ -3152,39 +3184,26 @@ static int video_get_user(void __user *arg, void *parg, unsigned int cmd, break; } #endif - default: - /* - * In some cases, only a few fields are used as input, - * i.e. when the app sets "index" and then the driver - * fills in the rest of the structure for the thing - * with that index. We only need to copy up the first - * non-input field. - */ - if (v4l2_is_known_ioctl(cmd)) { - u32 flags = v4l2_ioctls[_IOC_NR(cmd)].flags; - - if (flags & INFO_FL_CLEAR_MASK) - n = (flags & INFO_FL_CLEAR_MASK) >> 16; - *always_copy = flags & INFO_FL_ALWAYS_COPY; - } - - if (copy_from_user(parg, (void __user *)arg, n)) - return -EFAULT; - - /* zero out anything we don't copy from userspace */ - if (n < _IOC_SIZE(cmd)) - memset((u8 *)parg + n, 0, _IOC_SIZE(cmd) - n); - break; } - return 0; } -static int video_put_user(void __user *arg, void *parg, unsigned int cmd) +static int video_put_user(void __user *arg, void *parg, + unsigned int real_cmd, unsigned int cmd) { if (!(_IOC_DIR(cmd) & _IOC_READ)) return 0; + if (cmd == real_cmd) { + /* Copy results into user buffer */ + if (copy_to_user(arg, parg, _IOC_SIZE(cmd))) + return -EFAULT; + return 0; + } + + if (in_compat_syscall()) + return v4l2_compat_put_user(arg, parg, cmd); + switch (cmd) { #ifdef CONFIG_COMPAT_32BIT_TIME case VIDIOC_DQEVENT_TIME32: { @@ -3231,11 +3250,6 @@ static int video_put_user(void __user *arg, void *parg, unsigned int cmd) break; } #endif - default: - /* Copy results into user buffer */ - if (copy_to_user(arg, parg, _IOC_SIZE(cmd))) - return -EFAULT; - break; } return 0; @@ -3269,8 +3283,8 @@ video_usercopy(struct file *file, unsigned int orig_cmd, unsigned long arg, parg = mbuf; } - err = video_get_user((void __user *)arg, parg, orig_cmd, - &always_copy); + err = video_get_user((void __user *)arg, parg, cmd, + orig_cmd, &always_copy); if (err) goto out; } @@ -3292,7 +3306,14 @@ video_usercopy(struct file *file, unsigned int orig_cmd, unsigned long arg, if (NULL == mbuf) goto out_array_args; err = -EFAULT; - if (copy_from_user(mbuf, user_ptr, array_size)) + if (in_compat_syscall()) + err = v4l2_compat_get_array_args(file, mbuf, user_ptr, + array_size, orig_cmd, + parg); + else + err = copy_from_user(mbuf, user_ptr, array_size) ? + -EFAULT : 0; + if (err) goto out_array_args; *kernel_ptr = mbuf; } @@ -3313,7 +3334,11 @@ video_usercopy(struct file *file, unsigned int orig_cmd, unsigned long arg, if (has_array_args) { *kernel_ptr = (void __force *)user_ptr; - if (copy_to_user(user_ptr, mbuf, array_size)) + if (in_compat_syscall()) + err = v4l2_compat_put_array_args(file, user_ptr, mbuf, + array_size, orig_cmd, + parg); + else if (copy_to_user(user_ptr, mbuf, array_size)) err = -EFAULT; goto out_array_args; } @@ -3325,7 +3350,7 @@ video_usercopy(struct file *file, unsigned int orig_cmd, unsigned long arg, goto out; out_array_args: - if (video_put_user((void __user *)arg, parg, orig_cmd)) + if (video_put_user((void __user *)arg, parg, cmd, orig_cmd)) err = -EFAULT; out: kvfree(mbuf); diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h index 86878fba332b..0db79f36c496 100644 --- a/include/media/v4l2-ioctl.h +++ b/include/media/v4l2-ioctl.h @@ -686,6 +686,17 @@ long int v4l2_compat_ioctl32(struct file *file, unsigned int cmd, unsigned long arg); #endif +unsigned int v4l2_compat_translate_cmd(unsigned int cmd); +int v4l2_compat_get_user(void __user *arg, void *parg, unsigned int cmd); +int v4l2_compat_put_user(void __user *arg, void *parg, unsigned int cmd); +int v4l2_compat_get_array_args(struct file *file, void *mbuf, + void __user *user_ptr, size_t array_size, + unsigned int cmd, void *arg); +int v4l2_compat_put_array_args(struct file *file, void __user *user_ptr, + void *mbuf, size_t array_size, + unsigned int cmd, void *arg); + + /** * typedef v4l2_kioctl - Typedef used to pass an ioctl handler. *