From: <frederic.chen@mediatek.com>
To: <hans.verkuil@cisco.com>,
<laurent.pinchart+renesas@ideasonboard.com>, <tfiga@chromium.org>,
<matthias.bgg@gmail.com>, <mchehab@kernel.org>
Cc: Sean.Cheng@mediatek.com, srv_heupstream@mediatek.com,
sj.huang@mediatek.com, yuzhao@chromium.org,
linux-mediatek@lists.infradead.org, zwisler@chromium.org,
christie.yu@mediatek.com, frederic.chen@mediatek.com,
linux-arm-kernel@lists.infradead.org,
linux-media@vger.kernel.org
Subject: [PATCH V2, 0/1] media: change media_device_request_alloc to match media_ioctl_info
Date: Thu, 6 Aug 2020 23:58:21 +0800 [thread overview]
Message-ID: <20200806155822.3772-1-frederic.chen@mediatek.com> (raw)
Hello,
This patch is to modify media_device_request_alloc() so that it can pass
CFI(Control Flow Integrity) check. I would like some review comments.
media_device_request_alloc() is saved in fn of media_ioctl_info struct,
which is defined as long (*fn)(struct media_device *dev, void *arg). The
type of the second parameter of media_device_request_alloc() is int* now,
but it is void* in fn of media_ioctl_info. We got some ABI violation here.
Therefore, we would like to use void* instead of int* for the second
parameter of media_device_request_alloc().
static long media_device_request_alloc(struct media_device *mdev,
int *alloc_fd);
struct media_ioctl_info {
unsigned int cmd;
unsigned short flags;
long (*fn)(struct media_device *dev, void *arg);
long (*arg_from_user)(void *karg, void __user *uarg, unsigned int cmd);
long (*arg_to_user)(void __user *uarg, void *karg, unsigned int cmd);
};
Here is an example. With Android’s CFI checking, we got the following error
without this change.
[ 23.502477] mtk-cam soc:camisp: sd:mtk-cam raw-0 pad:2 set format w/h/code 2328/1748/0x3007
[ 23.518690] Kernel panic - not syncing: CFI failure (target: media_device_request_alloc+0x0/0x4)
[ 23.519804] CPU: 7 PID: 818 Comm: mtkv4l2_ut Tainted: G S O 5.4.39-g02c0a4858bed-dirty #45
[ 23.521553] Call trace:
[ 23.521868] dump_backtrace.cfi_jt+0x0/0x4
[ 23.522389] dump_stack+0xb8/0x114
[ 23.522824] panic+0x170/0x3e0
[ 23.523215] __ubsan_handle_cfi_check_fail_abort+0x0/0x14
[ 23.523896] perf_proc_update_handler+0x0/0xcc
[ 23.524460] __cfi_check+0x610cc/0x68ef0
[ 23.524959] media_device_ioctl+0x218/0x238
[ 23.525488] media_device_compat_ioctl+0x60/0x7c
[ 23.526072] media_compat_ioctl+0x58/0x9c
[ 23.526581] __arm64_compat_sys_ioctl+0x10c/0x434
[ 23.527176] el0_svc_common+0xb4/0x18c
[ 23.527651] el0_svc_compat_handler+0x1c/0x28
[ 23.528202] el0_svc_compat+0x8/0x24
[ 23.528659] SMP: stopping secondary CPUs
[ 23.529161] Kernel Offset: 0x24b8c00000 from 0xffffffc010000000
[ 23.529906] PHYS_OFFSET: 0xffffffdd00000000
[ 23.530434] CPU features: 0x00000006,2a80a238
[ 23.530983] Memory Limit: none
PPL_LOG_STORE: check once, sig value 0x27, addr 0x116000.
==================
Changes in v2
==================
We also removed the type cast in the MEDIA_IOC_ARG define .
Frederic Chen (1):
media: mc-device.c: change media_device_request_alloc to match
media_ioctl_info
drivers/media/mc/mc-device.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
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next reply other threads:[~2020-08-06 16:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-06 15:58 frederic.chen [this message]
2020-08-06 15:58 ` [PATCH V2, 1/1] media: mc-device.c: change media_device_request_alloc to match media_ioctl_info frederic.chen
2020-08-08 22:04 ` [PATCH V2,1/1] " Laurent Pinchart
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