Nikita Zhandarovich 1d6de21f00 media: dvb-frontends: dib3000mb: fix uninit-value in dib3000_write_reg
[ Upstream commit 2dd59fe0e19e1ab955259978082b62e5751924c7 ]

Syzbot reports [1] an uninitialized value issue found by KMSAN in
dib3000_read_reg().

Local u8 rb[2] is used in i2c_transfer() as a read buffer; in case
that call fails, the buffer may end up with some undefined values.

Since no elaborate error handling is expected in dib3000_write_reg(),
simply zero out rb buffer to mitigate the problem.

[1] Syzkaller report
dvb-usb: bulk message failed: -22 (6/0)
=====================================================
BUG: KMSAN: uninit-value in dib3000mb_attach+0x2d8/0x3c0 drivers/media/dvb-frontends/dib3000mb.c:758
 dib3000mb_attach+0x2d8/0x3c0 drivers/media/dvb-frontends/dib3000mb.c:758
 dibusb_dib3000mb_frontend_attach+0x155/0x2f0 drivers/media/usb/dvb-usb/dibusb-mb.c:31
 dvb_usb_adapter_frontend_init+0xed/0x9a0 drivers/media/usb/dvb-usb/dvb-usb-dvb.c:290
 dvb_usb_adapter_init drivers/media/usb/dvb-usb/dvb-usb-init.c:90 [inline]
 dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:186 [inline]
 dvb_usb_device_init+0x25a8/0x3760 drivers/media/usb/dvb-usb/dvb-usb-init.c:310
 dibusb_probe+0x46/0x250 drivers/media/usb/dvb-usb/dibusb-mb.c:110
...
Local variable rb created at:
 dib3000_read_reg+0x86/0x4e0 drivers/media/dvb-frontends/dib3000mb.c:54
 dib3000mb_attach+0x123/0x3c0 drivers/media/dvb-frontends/dib3000mb.c:758
...

Fixes: 74340b0a8b ("V4L/DVB (4457): Remove dib3000-common-module")
Reported-by: syzbot+c88fc0ebe0d5935c70da@syzkaller.appspotmail.com
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Link: https://lore.kernel.org/r/20240517155800.9881-1-n.zhandarovich@fintech.ru
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-01-02 10:31:59 +01:00
2024-12-27 13:58:53 +01:00
2024-12-14 20:00:03 +01:00
2024-12-27 13:58:58 +01:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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