Re: [PATCH] i2c: core-smbus: prevent stack corruption on read I2C_BLOCK_DATA

[Greg KH <greg@kroah.com>]

On Mon, Apr 01, 2019 at 01:54:41PM -0700, Connor O'Brien wrote:
> From: Jeremy Compostella <jeremy.compostella@intel.com>
> 
> commit 89c6efa61f5709327ecfa24bff18e57a4e80c7fa upstream.
> 
> On a I2C_SMBUS_I2C_BLOCK_DATA read request, if data->block[0] is
> greater than I2C_SMBUS_BLOCK_MAX + 1, the underlying I2C driver writes
> data out of the msgbuf1 array boundary.
> 
> It is possible from a user application to run into that issue by
> calling the I2C_SMBUS ioctl with data.block[0] greater than
> I2C_SMBUS_BLOCK_MAX + 1.
> 
> This patch makes the code compliant with
> Documentation/i2c/dev-interface by raising an error when the requested
> size is larger than 32 bytes.
> 
> Call Trace:
>  [<ffffffff8139f695>] dump_stack+0x67/0x92
>  [<ffffffff811802a4>] panic+0xc5/0x1eb
>  [<ffffffff810ecb5f>] ? vprintk_default+0x1f/0x30
>  [<ffffffff817456d3>] ? i2cdev_ioctl_smbus+0x303/0x320
>  [<ffffffff8109a68b>] __stack_chk_fail+0x1b/0x20
>  [<ffffffff817456d3>] i2cdev_ioctl_smbus+0x303/0x320
>  [<ffffffff81745aed>] i2cdev_ioctl+0x4d/0x1e0
>  [<ffffffff811f761a>] do_vfs_ioctl+0x2ba/0x490
>  [<ffffffff81336e43>] ? security_file_ioctl+0x43/0x60
>  [<ffffffff811f7869>] SyS_ioctl+0x79/0x90
>  [<ffffffff81a22e97>] entry_SYSCALL_64_fastpath+0x12/0x6a
> 
> Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
> Cc: stable@kernel.org
> [connoro@google.com: 4.9 backport: adjust filename]
> Signed-off-by: Connor O'Brien <connoro@google.com>
> ---
>  drivers/i2c/i2c-core.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)

Thanks for these, now applied.

greg k-h