user/sven/linux.git/drivers/i2c/i2c-dev.c, branch v4.9.296

i2c: dev: zero out array used for i2c reads from userspace

2021-08-26T12:37:22Z

commit 86ff25ed6cd8240d18df58930bd8848b19fce308 upstream. If an i2c driver happens to not provide the full amount of data that a user asks for, it is possible that some uninitialized data could be sent to userspace. While all in-kernel drivers look to be safe, just be sure by initializing the buffer to zero before it is passed to the i2c driver so that any future drivers will not have this issue. Also properly copy the amount of data recvieved to the userspace buffer, as pointed out by Dan Carpenter. Reported-by: Eric Dumazet Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Wolfram Sang Signed-off-by: Greg Kroah-Hartman

i2c: dev: Fix the race between the release of i2c_dev and cdev

2020-05-27T14:41:51Z

[ Upstream commit 1413ef638abae4ab5621901cf4d8ef08a4a48ba6 ] The struct cdev is embedded in the struct i2c_dev. In the current code, we would free the i2c_dev struct directly in put_i2c_dev(), but the cdev is manged by a kobject, and the release of it is not predictable. So it is very possible that the i2c_dev is freed before the cdev is entirely released. We can easily get the following call trace with CONFIG_DEBUG_KOBJECT_RELEASE and CONFIG_DEBUG_OBJECTS_TIMERS enabled. ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x38 WARNING: CPU: 19 PID: 1 at lib/debugobjects.c:325 debug_print_object+0xb0/0xf0 Modules linked in: CPU: 19 PID: 1 Comm: swapper/0 Tainted: G W 5.2.20-yocto-standard+ #120 Hardware name: Marvell OcteonTX CN96XX board (DT) pstate: 80c00089 (Nzcv daIf +PAN +UAO) pc : debug_print_object+0xb0/0xf0 lr : debug_print_object+0xb0/0xf0 sp : ffff00001292f7d0 x29: ffff00001292f7d0 x28: ffff800b82151788 x27: 0000000000000001 x26: ffff800b892c0000 x25: ffff0000124a2558 x24: 0000000000000000 x23: ffff00001107a1d8 x22: ffff0000116b5088 x21: ffff800bdc6afca8 x20: ffff000012471ae8 x19: ffff00001168f2c8 x18: 0000000000000010 x17: 00000000fd6f304b x16: 00000000ee79de43 x15: ffff800bc0e80568 x14: 79616c6564203a74 x13: 6e6968207473696c x12: 5f72656d6974203a x11: ffff0000113f0018 x10: 0000000000000000 x9 : 000000000000001f x8 : 0000000000000000 x7 : ffff0000101294cc x6 : 0000000000000000 x5 : 0000000000000000 x4 : 0000000000000001 x3 : 00000000ffffffff x2 : 0000000000000000 x1 : 387fc15c8ec0f200 x0 : 0000000000000000 Call trace: debug_print_object+0xb0/0xf0 __debug_check_no_obj_freed+0x19c/0x228 debug_check_no_obj_freed+0x1c/0x28 kfree+0x250/0x440 put_i2c_dev+0x68/0x78 i2cdev_detach_adapter+0x60/0xc8 i2cdev_notifier_call+0x3c/0x70 notifier_call_chain+0x8c/0xe8 blocking_notifier_call_chain+0x64/0x88 device_del+0x74/0x380 device_unregister+0x54/0x78 i2c_del_adapter+0x278/0x2d0 unittest_i2c_bus_remove+0x3c/0x80 platform_drv_remove+0x30/0x50 device_release_driver_internal+0xf4/0x1c0 driver_detach+0x58/0xa0 bus_remove_driver+0x84/0xd8 driver_unregister+0x34/0x60 platform_driver_unregister+0x20/0x30 of_unittest_overlay+0x8d4/0xbe0 of_unittest+0xae8/0xb3c do_one_initcall+0xac/0x450 do_initcall_level+0x208/0x224 kernel_init_freeable+0x2d8/0x36c kernel_init+0x18/0x108 ret_from_fork+0x10/0x1c irq event stamp: 3934661 hardirqs last enabled at (3934661): [] debug_exception_exit+0x4c/0x58 hardirqs last disabled at (3934660): [] debug_exception_enter+0xa4/0xe0 softirqs last enabled at (3934654): [] __do_softirq+0x46c/0x628 softirqs last disabled at (3934649): [] irq_exit+0x104/0x118 This is a common issue when using cdev embedded in a struct. Fortunately, we already have a mechanism to solve this kind of issue. Please see commit 233ed09d7fda ("chardev: add helper function to register char devs with a struct device") for more detail. In this patch, we choose to embed the struct device into the i2c_dev, and use the API provided by the commit 233ed09d7fda to make sure that the release of i2c_dev and cdev are in sequence. Signed-off-by: Kevin Hao Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin

i2c: dev: fix potential memory leak in i2cdev_ioctl_rdwr

2019-06-22T06:17:23Z

[ Upstream commit a0692f0eef91354b62c2b4c94954536536be5425 ] If I2C_M_RECV_LEN check failed, msgs[i].buf allocated by memdup_user will not be freed. Pump index up so it will be freed. Fixes: 838bfa6049fb ("i2c-dev: Add support for I2C_M_RECV_LEN") Signed-off-by: Yingjoe Chen Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin

i2c: dev: prevent adapter retries and timeout being set as minus value

2019-01-16T21:12:32Z

commit 6ebec961d59bccf65d08b13fc1ad4e6272a89338 upstream. If adapter->retries is set to a minus value from user space via ioctl, it will make __i2c_transfer and __i2c_smbus_xfer skip the calling to adapter->algo->master_xfer and adapter->algo->smbus_xfer that is registered by the underlying bus drivers, and return value 0 to all the callers. The bus driver will never be accessed anymore by all users, besides, the users may still get successful return value without any error or information log print out. If adapter->timeout is set to minus value from user space via ioctl, it will make the retrying loop in __i2c_transfer and __i2c_smbus_xfer always break after the the first try, due to the time_after always returns true. Signed-off-by: Yi Zeng [wsa: minor grammar updates to commit message] Signed-off-by: Wolfram Sang Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman

i2c: fix kernel memory disclosure in dev interface

2017-01-19T19:18:02Z

commit 30f939feaeee23e21391cfc7b484f012eb189c3c upstream. i2c_smbus_xfer() does not always fill an entire block, allowing kernel stack memory disclosure through the temp variable. Clear it before it's read to. Signed-off-by: Vlad Tsyrklevich Signed-off-by: Wolfram Sang Signed-off-by: Greg Kroah-Hartman

i2c-dev: don't get i2c adapter via i2c_dev

2016-07-08T01:29:31Z

There is no code protecting i2c_dev to be freed after it is returned from i2c_dev_get_by_minor() and using it to access the value which we already have (minor) isn't safe really. Avoid using it and get the adapter directly from 'minor'. Signed-off-by: Viresh Kumar Reviewed-by: Jean Delvare Tested-by: Jean Delvare Signed-off-by: Wolfram Sang

i2c: dev: use after free in detach

2016-05-28T15:37:42Z

The call to put_i2c_dev() frees "i2c_dev" so there is a use after free when we call cdev_del(&i2c_dev->cdev). Fixes: d6760b14d4a1 ('i2c: dev: switch from register_chrdev to cdev API') Signed-off-by: Dan Carpenter Signed-off-by: Wolfram Sang

i2c: dev: don't start function name with 'return'

2016-05-27T11:13:01Z

I stumbled multiple times over 'return_i2c_dev', especially before the actual 'return res'. It makes the code hard to read, so reanme the function to 'put_i2c_dev' which also better matches 'get_free_i2c_dev'. Signed-off-by: Wolfram Sang

i2c: dev: switch from register_chrdev to cdev API

2016-05-26T19:18:57Z

i2c-dev had never moved away from the older register_chrdev interface to implement its char device registration. The register_chrdev API has the limitation of enabling only up to 256 i2c-dev busses to exist. Large platforms with lots of i2c devices (i.e. pluggable transceivers) with dedicated busses may have to exceed that limit. In particular, there are also platforms making use of the i2c bus multiplexing API, which instantiates a virtual bus for each possible multiplexed selection. This patch removes the register_chrdev usage and replaces it with the less old cdev API, which takes away the 256 i2c-dev bus limitation. It should not have any other impact for i2c bus drivers or user space. This patch has been tested on qemu x86 and qemu powerpc platforms with the aid of a module which adds and removes 5000 virtual i2c busses, as well as validated on an existing powerpc hardware platform which makes use of the i2c bus multiplexing API. i2c-dev busses with device minor numbers larger than 256 have also been validated to work with the existing i2c-tools. Signed-off-by: Erico Nunes [wsa: kept includes sorted] Signed-off-by: Wolfram Sang

i2c: i2c-dev: sort includes

2016-02-20T22:33:38Z

I request this for drivers, so the core should adhere to sorted includes as well. Signed-off-by: Wolfram Sang